Compressive Testing of Stitched Frame and Stringer Alternate Configurations

NASA Technical Reports Server (NTRS)

Leone, Frank A., Jr.; Jegley, Dawn C.

2016-01-01

A series of single-frame and single-stringer compression tests were conducted at NASA Langley Research Center on specimens harvested from a large panel built using the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept. Different frame and stringer designs were used in fabrication of the PRSEUS panel. In this report, the details of the experimental testing of single-frame and single-stringer compression specimens are presented, as well as discussions on the performance of the various structural configurations included in the panel.

Pultruded Rod/Overwrap Testing for Various Stitched Stringer Configurations

NASA Technical Reports Server (NTRS)

Leone, Frank A., Jr.

2016-01-01

The unidirectional carbon pultruded rod running through the tops of the stringers is a key design feature of the Pultruded Rod Efficient Unitized Structure (PRSEUS) concept as applied to aircraft fuselage structure. Reported herein are the test methods and results from a test campaign in which the strength of the rod/overwrap interface of various PRSEUS stringer configurations were characterized. The different stringer configurations included different materials and stacking sequences for the stringer overwrap and whether or not an additional layer of adhesive was included between the rod and the overwrap.

Influence of Impact Damage on Carbon-Epoxy Stiffener Crippling

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.

2010-01-01

NASA, the Air Force Research Laboratory and The Boeing Company have worked to develop new low-cost, light-weight composite structures for aircraft. A Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept has been developed which offers advantages over traditional metallic structure. In this concept a stitched carbon-epoxy material system has been developed with the potential for reducing the weight and cost of transport aircraft structure by eliminating fasteners, thereby reducing part count and labor. By adding unidirectional carbon rods to the top of stiffeners, the panel becomes more structurally efficient. This combination produces a more damage tolerant design. This document describes the results of experimentation on PRSEUS specimens loaded in unidirectional compression subjected to impact damage and loaded in fatigue and to failure. A comparison with analytical predictions for pristine and damaged specimens is included.

Compressive Loading and Modeling of Stitched Composite Stiffeners

NASA Technical Reports Server (NTRS)

Leone, Frank A., Jr.; Jegley, Dawn C.; Linton, Kim A.

2016-01-01

A series of single-frame and single-stringer compression tests were conducted at NASA Langley Research Center on specimens harvested from a large panel built using the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept. Different frame and stringer designs were used in fabrication of the PRSEUS panel. In this paper, the details of the experimental testing of single-frame and single-stringer compression specimens are presented, as well as discussions on the performance of the various structural configurations included in the panel. Nonlinear finite element models were developed to further understand the failure processes observed during the experimental campaign.

Assessment of Damage Containment Features of a Full-Scale PRSEUS Fuselage Panel Through Test and Teardown

NASA Technical Reports Server (NTRS)

Bergan, Andrew C.; Bakuckas, John G., Jr.; Lovejoy, Andrew E.; Jegley, Dawn C.; Awerbuch, Jonathan; Tan, Tein-Min

2012-01-01

An area that shows promise in enhancing structural integrity of aircraft and aerospace structures is the integrally stitched composite technology. The most recent generation of this technology is the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept developed by Boeing Research and Technology and the National Aeronautics and Space Administration. A joint test program on the assessment of damage containment capabilities of the PRSEUS concept for curved fuselage structures was conducted recently at the Federal Aviation Administration William J. Hughes Technical Center. The panel was subjected to axial tension, internal pressure, and combined axial tension and internal pressure load conditions up to fracture, with a through-the-thickness, two-bay notch severing the central stiffener. For the purpose of future progressive failure analysis development and verification, extensive post failure nondestructive and teardown inspections were conducted. Detailed inspections were performed directly ahead of the notch tip where stable damage progression was observed. These examinations showed: 1) extensive delaminations developed ahead of the notch tip, 2) the extent and location of damage, 3) the typical damage mechanisms observed in composites, and 4) the role of stitching and warp-knitting in the failure mechanisms. The objective of this paper is to provide a summary of results from these posttest inspections.

Structural Integrity Testing Method for PRSEUS Rod-Wrap Stringer Design

NASA Technical Reports Server (NTRS)

Wang, John T.; Grenoble, Ray W.; Pickell, Robert D.

2012-01-01

NASA Langley Research Center and The Boeing Company are developing an innovative composite structural concept, called PRSEUS, for the flat center section of a future environmentally friendly hybrid wing body (HWB) aircraft. The PRSEUS (Pultruded Rod Stitched Efficient Unitized Structure) concept uses dry textile preforms for the skins, frames, and stiffener webs. The highly loaded stiffeners are made from precured unidirectional carbon/epoxy rods and dry fiber preforms. The rods are wrapped with the dry fiber preforms and a resin infusion process is used to form the rod-wrap stiffeners. The structural integrity of the rod-wrap interface is critical for maintaining the panel s high strength and bending rigidity. No standard testing method exists for testing the strength of the rod-wrap bondline. Recently, Boeing proposed a rod push-out testing method and conducted some preliminary tests using this method. This paper details an analytical study of the rod-wrap bondline. The rod-wrap interface is modeled as a cohesive zone for studying the initiation and growth of interfacial debonding during push-out testing. Based on the correlations of analysis results and Boeing s test data, the adequacy of the rod-wrap testing method is evaluated, and potential approaches for improvement of the test method are proposed.

Compressive Behavior of Frame-Stiffened Composite Panels

NASA Technical Reports Server (NTRS)

Yovanof, Nicolette P.; Jegley, Dawn C.

2011-01-01

New technologies are being developed under NASA's Environmentally Responsible Aviation (ERA) Program aimed at reducing fuel burn and emissions in large commercial aircraft. A Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept is being developed which offers advantages over traditional metallic structure. In this concept a stitched carbon-epoxy material system is employed with the potential for reducing the weight and cost of transport aircraft structure by eliminating fasteners and producing a more damage tolerant design. In addition, by adding unidirectional carbon rods to the top of stiffeners and minimizing the interference between the sandwich frames and the rod-stiffened stringers, the panel becomes more structurally efficient. This document describes the results of experimentation on a PRSEUS panel in which the frames are loaded in unidirectional compression beyond the local buckling of the skin of a Hybrid Wing Body (HWB) aircraft. A comparison with analytical predictions and the relationship between these test results and the global aircraft design is presented.

Status of Advanced Stitched Unitized Composite Aircraft Structures

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.; Velicki, Alex

2013-01-01

NASA has created the Environmentally Responsible Aviation (ERA) Project to explore and document the feasibility, benefits and technical risk of advanced vehicle configurations and enabling technologies that will reduce the impact of aviation on the environment. A critical aspect of this pursuit is the development of a lighter, more robust airframe that will enable the introduction of unconventional aircraft configurations that have higher lift-to-drag ratios, reduced drag, and lower community noise levels. The primary structural concept being developed under the ERA project in the Airframe Technology element is the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept. This paper describes how researchers at NASA and The Boeing Company are working together to develop fundamental PRSEUS technologies that could someday be implemented on a transport size aircraft with high aspect ratio wings or unconventional shapes such as a hybrid wing body airplane design.

Behavior of Frame-Stiffened Composite Panels with Damage

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.

2013-01-01

NASA, the Air Force Research Laboratory and The Boeing Company have worked to develop new low-cost, light-weight composite structures for aircraft. A Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept has been developed which offers advantages over traditional metallic structures. In this concept, a stitched carbon-epoxy material system has been developed with the potential for reducing the weight and cost of transport aircraft structure by eliminating fasteners, thereby reducing part count and labor. Stitching and the use of thin skins with rod-stiffeners to move loading away from the morevulnerable outer surface produces a structurally efficient, damage tolerant design. This study focuses on the behavior of PRSEUS panels loaded in the frame direction and subjected to severe damage in the form of a severed central frame in a three-frame panel. Experimental results for a pristine two-frame panel and analytical predictions for pristine two-frame and three-frame panels as well as damaged three-frame panels are described.

Applying a Stiffened Stitched Concept to Shear-Loaded Structure

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.

2014-01-01

NASA and The Boeing Company have worked to develop new low-cost, lightweight composite structures for aircraft. A stitched carbon-epoxy material system was developed to reduce the weight and cost of transport aircraft structure, first in the NASA Advanced Composites Technology (ACT) Program in the 1990's and now in the Environmentally Responsible Aviation (ERA) Project. By stitching through the thickness of a dry carbon fiber material prior to cure, the need for mechanical fasteners is almost eliminated. Stitching also provides the benefit of reducing or eliminating delaminations, including those between stiffener flanges and skin. The stitched panel concept used in the ACT program used simple blade-stiffeners as stringers, caps, and clips. Today, the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept is being developed for application to advanced vehicle configurations. PRSEUS provides additional weight savings through the use of a stiffener with a thin web and a unidirectional carbon rod at the top of the web which provides structurally efficient stiffening. Comparisons between stitched and unstitched structure and between blade-stiffened and rod-stiffened structure are presented focusing on a panel loaded in shear. Shear loading is representative of spar loading in wing structures.

PRSEUS Structural Concept Development

NASA Technical Reports Server (NTRS)

Velicki, Alex; Jegley, Dawn

2014-01-01

A lighter, more robust airframe is one of the key technological advancements necessary for the successful launch of any large next-generation transport aircraft. Such a premise dictates that considerable improvements beyond current state-of-the-art aluminum structures is needed, and that improvements of this magnitude will require an extensive use of composite materials that are not only lightweight, but also economical to produce. To address this challenge, researchers at NASA and The Boeing Company are developing a novel structural concept called the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) under the Environmentally Responsible Aviation (ERA) Project. It is an integrally stiffened panel concept that is stitched together and designed to maintain residual load-carrying capabilities under a variety of damage scenarios. In addition to improved structural performance, an important facet of this unique arrangement of stitched carbon fibers is its innovative manufacturing method that has the potential to lower fabrication costs by eliminating fasteners and autoclave cures. The rationale and development status for this new approach forms the basis of the work described in this paper. The test specimens described herein were fabricated, or are currently being fabricated, by The Boeing Company, while the structural analyses and testing tasks are being performed by NASA and Boeing personnel.

The Behavior of a Stitched Composite Large-Scale Multi-Bay Pressure Box

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.; Rouse, Marshall; Przekop, Adam; Lovejoy, Andrew E.

2016-01-01

NASA has created the Environmentally Responsible Aviation (ERA) Project to develop technologies to reduce impact of aviation on the environment. A critical aspect of this pursuit is the development of a lighter, more robust airframe to enable the introduction of unconventional aircraft configurations. NASA and The Boeing Company have worked together to develop a structural concept that is lightweight and an advancement beyond state-of-the-art composite structures. The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) is an integrally stiffened panel design where elements are stitched together and designed to maintain residual load-carrying capabilities under a variety of damage scenarios. With the PRSEUS concept, through-the-thickness stitches are applied through dry fabric prior to resin infusion, and replace fasteners throughout each integral panel. Through-the-thickness reinforcement at discontinuities, such as along flange edges, has been shown to suppress delamination and turn cracks, which expands the design space and leads to lighter designs. The pultruded rod provides stiffening away from the more vulnerable skin surface and improves bending stiffness. A series of building block tests were evaluated to explore the fundamental assumptions related to the capability and advantages of PRSEUS panels. The final step in the building block series of tests is an 80%-scale pressure box representing a portion of the center section of a Hybrid Wing Body (HWB) transport aircraft. The testing of this test article under maneuver and internal pressure loading conditions is the subject of this paper. The experimental evaluation of this article, along with the other building block tests and the accompanying analyses, has demonstrated the viability of a PRSEUS center body for the HWB vehicle. Additionally, much of the development effort is also applicable to traditional tube-and-wing aircraft, advanced aircraft configurations, and other structures where weight and through-the-thickness strength are design considerations.

Damage Arresting Composites for Shaped Vehicles - Phase II Final Report

NASA Technical Reports Server (NTRS)

Velicki, Alex; Yovanof, Nicolette; Baraja, Jaime; Linton, Kim; Li, Victor; Hawley, Arthur; Thrash, Patrick; DeCoux, Steve; Pickell, Robert

2011-01-01

This report describes the development of a novel structural concept, Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS), that addresses the demanding fuselage loading requirements for the Hybrid Wing or Blended Wing Body (BWB) airplane configuration. In addition to the analytical studies, a three specimen test program was also completed to assess the concept under axial tension loading, axial compression loading, and internal pressure loading.

Full-Scale Test and Analysis of a PRSEUS Fuselage Panel to Assess Damage-Containment Features

NASA Technical Reports Server (NTRS)

Bergan, Andrew; Bakuckas, John G.; Lovejoy, Andrew E.; Jegley, Dawn C.; Linton, Kim A.; Korkosz, Gregory; Awerbuch, Jonathan; Tan, Tein-Min

2011-01-01

Stitched composite technology has the potential to substantially decrease structural weight through enhanced damage containment capabilities. The most recent generation of stitched composite technology, the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept, has been shown to successfully arrest damage at the sub-component level through tension testing of a three stringer panel with damage in the form of a two-bay notch. In a joint effort undertaken by the National Aeronautics and Space Administration (NASA), the Federal Aviation Administration (FAA), and the Boeing Company, further studies are being conducted to characterize the damage containment features of the PRSEUS concept. A full-scale residual strength test will be performed on a fuselage panel to determine if the load capacity will meet strength, deformation, and damage tolerance requirements. A curved panel was designed, fabricated, and prepared for residual strength testing. A pre-test Finite Element Model (FEM) was developed using design allowables from previous test programs to predict test panel deformation characteristics and margins of safety. Three phases of testing with increasing damage severity include: (1) as manufactured; (2) barely visible impact damage (BVID) and visible impact damage (VID); and (3) discrete source damage (DSD) where the panel will be loaded to catastrophic failure. This paper presents the background information, test plan, and experimental procedure. This paper is the first of several future articles reporting the test preparations, results, and analysis conducted in the test program.

Acoustic Emission of Large PRSEUS Structures (Pultruded Rod Stitched Efficient Unitized Structure)

NASA Technical Reports Server (NTRS)

Horne, Michael R.; Juarez, Peter D.

2016-01-01

In the role of structural health monitoring (SHM), Acoustic Emission (AE) analysis is being investigated as an effective method for tracking damage development in large composite structures under load. Structures made using Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) for damage tolerant, light, and economical airframe construction are being pursued by The Boeing Company and NASA under the Environmentally Responsible Aircraft initiative (ERA). The failure tests of two PRSEUS substructures based on the Boeing Hybrid Wing Body fuselage concept were conducted during third quarter 2011 and second quarter 2015. One fundamental concern of these tests was determining the effectiveness of the stitched integral stiffeners to inhibit damage progression. By design, severe degradation of load carrying capability should not occur prior to Design Ultimate Load (DUL). While minor damage prior to DUL was anticipated, the integral stitching should not fail since this would allow a stiffener-skin delamination to progress rapidly and alter the transfer of load into the stiffeners. In addition, the stiffeners should not fracture because they are fundamental to structural integrity. Getting the best information from each AE sensor is a primary consideration because a sparse network of sensors is implemented. Sensitivity to stiffener-contiguous degradation is supported by sensors near the stiffeners, which increases the coverage per sensor via AE waveguide actions. Some sensors are located near potentially critical areas or "critical zones" as identified by numerical analyses. The approach is compared with the damage progression monitored by other techniques (e.g. ultrasonic C-scan).

Development of the PRSEUS Multi-Bay Pressure Box for a Hybrid Wing Body Vehicle

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.; Velicki, Alexander

2015-01-01

NASA has created the Environmentally Responsible Aviation Project to explore and document the feasibility, benefits, and technical risk of advanced vehicle configurations and enabling technologies that will reduce the impact of aviation on the environment. A critical aspect of this pursuit is the development of a lighter, more robust airframe that will enable the introduction of unconventional aircraft configurations that have higher lift-to-drag ratios, reduced drag, and lower community noise. Although such novel configurations like the Hybrid Wing Body (HWB) offer better aerodynamic performance as compared to traditional tube-and-wing aircraft, their blended wing shapes also pose significant new design challenges. Developing an improved structural concept that is capable of meeting the structural weight fraction allocated for these non-circular pressurized cabins is the primary obstacle in implementing large lifting-body designs. To address this challenge, researchers at NASA and The Boeing Company are working together to advance new structural concepts like the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS), which is an integrally stiffened panel design that is stitched together and designed to maintain residual load-carrying capabilities under a variety of damage scenarios. The large-scale multi-bay fuselage test article described in this paper is the final specimen in a building-block test program that was conceived to demonstrate the feasibility of meeting the structural weight goals established for the HWB pressure cabin.

Analysis of a Hybrid Wing Body Center Section Test Article

NASA Technical Reports Server (NTRS)

Wu, Hsi-Yung T.; Shaw, Peter; Przekop, Adam

2013-01-01

The hybrid wing body center section test article is an all-composite structure made of crown, floor, keel, bulkhead, and rib panels utilizing the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) design concept. The primary goal of this test article is to prove that PRSEUS components are capable of carrying combined loads that are representative of a hybrid wing body pressure cabin design regime. This paper summarizes the analytical approach, analysis results, and failure predictions of the test article. A global finite element model of composite panels, metallic fittings, mechanical fasteners, and the Combined Loads Test System (COLTS) test fixture was used to conduct linear structural strength and stability analyses to validate the specimen under the most critical combination of bending and pressure loading conditions found in the hybrid wing body pressure cabin. Local detail analyses were also performed at locations with high stress concentrations, at Tee-cap noodle interfaces with surrounding laminates, and at fastener locations with high bearing/bypass loads. Failure predictions for different composite and metallic failure modes were made, and nonlinear analyses were also performed to study the structural response of the test article under combined bending and pressure loading. This large-scale specimen test will be conducted at the COLTS facility at the NASA Langley Research Center.

Initial Evaluation of Acoustic Emission SHM of PRSEUS Multi-bay Box Tests

NASA Technical Reports Server (NTRS)

Horne, Michael R.; Madaras, Eric I.

2016-01-01

A series of tests of the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) HWB Multi-Bay Test Article were conducted during the second quarter of 2015 at NASA Langley Research Center (LaRC) in the Combined Loads Test facility (COLTS). This report documents the Acoustic Emission (AE) data collected during those tests along with an initial analysis of the data. A more detailed analysis will be presented in future publications.

Damage Arresting Composites for Shaped Vehicles

NASA Technical Reports Server (NTRS)

Velicki, Alex

2009-01-01

This report describes the development of a novel structural solution that addresses the demanding fuselage loading requirements for the Hybrid Wing or Blended Wing Body configurations that are described in NASA NRA subtopic A2A.3, "Materials and Structures for Wing Components and Non-Circular Fuselage." The phase I portion of this task includes a comprehensive finite element model-based structural sizing exercise performed using the BWB airplane configuration to generate internal loads and fuselage panel weights for an advanced Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) structural concept. An accompanying element-level test program is also described which substantiates the analytical results and calculation methods used in the trade study. The phase II plan for the continuation of this research is also included herein.

Pulse-Echo Phased Array Ultrasonic Inspection of Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS)

NASA Technical Reports Server (NTRS)

Johnston, Pat H.

2010-01-01

A PRSEUS test article was subjected to controlled impact on the skin face followed by static and cyclic axial compressions. Phased array ultrasonic inspection was conducted before impact, and after each of the test conditions. A linear phased array probe with a manual X-Y scanner was used for interrogation. Ultrasound showed a delamination between the skin and stringer flange adjacent to the impact. As designed, the stitching in the flange arrested the lateral flaw formation. Subsequent ultrasonic data showed no delamination growth due to continued loading. Keywords: Phased Array, Ultrasonics, Composites, Out-of-Autoclave

Evaluation of Acoustic Emission SHM of PRSEUS Composite Pressure Cube Tests

NASA Technical Reports Server (NTRS)

Horne, Michael R.; Madaras, Eric I.

2013-01-01

A series of tests of the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) pressure cube were conducted during third quarter 2011 at NASA Langley Research Center (LaRC) in the Combined Loads Test facility (COLTS). This is a report of the analysis of the Acoustic Emission (AE) data collected during those tests. The AE signals of the later tests are consistent with the final failure progression through two of the pressure cube panels. Calibration tests and damage precursor AE indications, from preliminary checkout pressurizations, indicated areas of concern that eventually failed. Hence those tests have potential for vehicle health monitoring.

Ultrasonic Nondestructive Evaluation of PRSEUS Pressure Cube Article in Support of Load Test to Failure

NASA Technical Reports Server (NTRS)

Johnston, Patrick H.

2013-01-01

The PRSEUS Pressure Cube Test was a joint development effort between the Boeing Company and NASA Langley Research Center, sponsored in part by the Environmentally Responsible Aviation Project and Boeing internal R&D. This Technical Memorandum presents the results of ultrasonic inspections in support of the PRSEUS Pressure Cube Test, and is a companion document with the NASA test report and a report on the acoustic emission measurements made during the test.

Hybrid-Wing-Body Vehicle Composite Fuselage Analysis and Case Study

NASA Technical Reports Server (NTRS)

Mukhopadhyay, Vivek

2014-01-01

Recent progress in the structural analysis of a Hybrid Wing-Body (HWB) fuselage concept is presented with the objective of structural weight reduction under a set of critical design loads. This pressurized efficient HWB fuselage design is presently being investigated by the NASA Environmentally Responsible Aviation (ERA) project in collaboration with the Boeing Company, Huntington Beach. The Pultruded Rod-Stiffened Efficient Unitized Structure (PRSEUS) composite concept, developed at the Boeing Company, is approximately modeled for an analytical study and finite element analysis. Stiffened plate linear theories are employed for a parametric case study. Maximum deflection and stress levels are obtained with appropriate assumptions for a set of feasible stiffened panel configurations. An analytical parametric case study is presented to examine the effects of discrete stiffener spacing and skin thickness on structural weight, deflection and stress. A finite-element model (FEM) of an integrated fuselage section with bulkhead is developed for an independent assessment. Stress analysis and scenario based case studies are conducted for design improvement. The FEM model specific weight of the improved fuselage concept is computed and compared to previous studies, in order to assess the relative weight/strength advantages of this advanced composite airframe technology

PRSEUS Pressure Cube Test Data and Response

NASA Technical Reports Server (NTRS)

Lovejoy, Andrew E.

2013-01-01

NASA s Environmentally Responsible Aviation (ERA) Program is examining the hybrid wing body (HWB) aircraft, among others, in an effort to increase the fuel efficiency of commercial aircraft. The HWB design combines features of a flying wing with features of conventional transport aircraft, and has the advantage of simultaneously increasing both fuel efficiency and payload. Recent years have seen an increased focus on the structural performance of the HWB. The key structural challenge of a HWB airframe is the ability to create a cost and weight efficient, non-circular, pressurized shell. Conventional round fuselage sections react cabin pressure by hoop tension. However, the structural configuration of the HWB subjects the majority of the structural panels to bi-axial, in-plane loads in addition to the internal cabin pressure, which requires more thorough examination and analysis than conventional transport aircraft components having traditional and less complex load paths. To address this issue, while keeping structural weights low, extensive use of advanced composite materials is made. This report presents the test data and preliminary conclusions for a pressurized cube test article that utilizes Boeing's Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS), and which is part of the building block approach used for HWB development.

Notched Strength Allowables and Inplane Shear Strength of AS4/VRM-34 Textile Laminates

NASA Technical Reports Server (NTRS)

Grenoble, Ray W.; Johnston, William M.

2013-01-01

Notched and unnotched strength allowables were developed for a textile composite to provide input data to analytical structural models based on the Pultruded Rod Stiffened Efficient Unitized Structure (PRSEUS) concept. Filled-hole tensile strength, filled-hole compressive strength, and inplane shear strength along stitch lines have been measured. The material system evaluated in this study is based on warp-knitted preforms of AS4 carbon fibers and VRM-34 epoxy resin, which have been processed via resin infusion and oven curing. All specimens were tested in as-fabricated (dry) condition. Filled-hole strengths were evaluated with and without through-thickness stitching. The effects of scaling on filled-hole tensile strength were evaluated by testing specimens in two widths, but with identical width / hole-diameter ratios. Inplane shear specimens were stitched in two configurations, and two specimen thicknesses were tested for each stitch configuration.

Repair Concepts as Design Constraints of a Stiffened Composite PRSEUS Panel

NASA Technical Reports Server (NTRS)

Przekop, Adam

2012-01-01

A design and analysis of a repair concept applicable to a stiffened thin-skin composite panel based on the Pultruded Rod Stitched Efficient Unitized Structure is presented. The concept is a bolted repair using metal components, so that it can easily be applied in the operational environment. The damage scenario considered is a midbay-to-midbay saw-cut with a severed stiffener, flange and skin. In a previous study several repair configurations were explored and their feasibility confirmed but refinement was needed. The present study revisits the problem under recently revised design requirements and broadens the suite of loading conditions considered. The repair assembly design is based on the critical tension loading condition and subsequently its robustness is verified for a pressure loading case. High fidelity modeling techniques such as mesh-independent definition of compliant fasteners, elastic-plastic material properties for metal parts and geometrically nonlinear solutions are utilized in the finite element analysis. The best repair design is introduced, its analysis results are presented and factors influencing the design are assessed and discussed.

Testing and Analysis Validation of a Metallic Repair Applied to a PRSEUS Tension Panel

NASA Technical Reports Server (NTRS)

Przekop, Adam; Jegley, Dawn C.

2013-01-01

A design and analysis of a repair concept applicable to a stiffened composite panel based on the Pultruded Rod Stitched Efficient Unitized Structure was recently completed. The damage scenario considered was a midbay-to-midbay saw-cut with a severed stiffener, flange and skin. Advanced modeling techniques such as mesh-independent definition of compliant fasteners and elastic-plastic material properties for metal parts were utilized in the finite element analysis supporting the design effort. A bolted metallic repair was selected so that it could be easily applied in the operational environment. The present work describes results obtained from a tension panel test conducted to validate both the repair concept and finite element analysis techniques used in the design effort. The test proved that the proposed repair concept is capable of sustaining load levels that are higher than those resulting from the current working stress allowables. This conclusion enables upward revision of the stress allowables that had been kept at an overly-conservative level due to concerns associated with repairability of the panels. Correlation of test data with finite element analysis results is also presented and assessed.

Imparting Barely Visible Impact Damage to a Stitched Composite Large-Scale Pressure Box

NASA Technical Reports Server (NTRS)

Lovejoy, Andrew E.; Przekop, Adam

2016-01-01

The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) is a concept that was developed by The Boeing Company to address the complex structural design aspects associated with a pressurized hybrid wing body (HWB) aircraft configuration, which has been a focus of the NASA Environmentally Responsible Aviation Project. The NASA-Boeing structural development for the HWB aircraft culminated in testing of the multi-bay box, which is an 80%-scale representation of the pressurized center-body section. This structure was tested in the NASA Langley Research Center Combined Loads Test System facility. As part of this testing, barely visible impact damage was imparted to the interior and exterior of the test article to demonstrate compliance with a condition representative of the requirements for Category 1 damaged composite structure as defined by the Federal Aviation Regulations. Interior impacts were imparted using an existing spring-loaded impactor, while the exterior impacts were imparted using a newly designed, gravity-driven impactor. This paper describes the impacts to the test article, and the design of the gravitydriven guided-weight impactor. The guided-weight impactor proved to be a very reliable method to impart barely visible impact damage in locations which are not easily accessible for a traditional drop-weight impactor, while at the same time having the capability to be highly configurable for use on other aircraft structures.

Material Property Characterization of AS4/VRM-34 Textile Laminates

NASA Technical Reports Server (NTRS)

Grenoble, Ray W.; Johnston, William M

2013-01-01

Several material properties (modulus, strengths, and fracture toughness) of a textile composite have been evaluated to provide input data to analytical models of Pultruded Rod Stiffened Efficient Unitized Structure (PRSEUS). The material system is based on warp-knitted preforms of AS4 carbon fibers and VRM-34 epoxy resin, which have been processed via resin infusion and oven curing. Tensile, compressive, shear, and fracture toughness properties have been measured at ambient and elevated temperatures. All specimens were tested in as-fabricated (dry) condition. Specimens were tested with and without through-thickness stitching.

T-Cap Pull-Off and Bending Behavior for Stitched Structure

NASA Technical Reports Server (NTRS)

Lovejoy, Andrew E.; Leone, Frank A., Jr.

2016-01-01

The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) is a structural concept that was developed by The Boeing Company to address the complex structural design aspects associated with a pressurized hybrid wing body aircraft configuration. An important design feature required for assembly is the integrally stitched T-cap, which provides connectivity of the corner (orthogonal) joint between adjacent panels. A series of tests were conducted on T-cap test articles, with and without a rod stiffener penetrating the T-cap web, under tension (pull-off) and bending loads. Three designs were tested, including the baseline design used in largescale test articles. The baseline had only the manufacturing stitch row adjacent to the fillet at the base of the T-cap web. Two new designs added stitching rows to the T-cap web at either 0.5- or 1.0-inch spacing along the height of the web. Testing was conducted at NASA Langley Research Center to determine the behavior of the T-cap region resulting from the applied loading. Results show that stitching arrests the initial delamination failures so that the maximum strength capability exceeds the load at which the initial delaminations develop. However, it was seen that the added web stitching had very little effect on the initial delamination failure load, but actually decreased the initial delamination failure load for tension loading of test articles without a stiffener passing through the web. Additionally, the added web stitching only increased the maximum load capability by between 1% and 12.5%. The presence of the stiffener, however, did increase the initial and maximum loads for both tension and bending loading as compared to the stringerless baseline design. Based on the results of the few samples tested, the additional stitching in the T-cap web showed little advantage over the baseline design in terms of structural failure at the T-cap web/skin junction for the current test articles.

Tension and Bending Testing of an Integral T-Cap for Stitched Composite Airframe Joints

NASA Technical Reports Server (NTRS)

Lovejoy, Andrew E.; Leone, Frank A., Jr.

2016-01-01

The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) is a structural concept that was developed by The Boeing Company to address the complex structural design aspects associated with a pressurized hybrid wing body aircraft configuration. An important design feature required for assembly is the integrally stitched T-cap, which provides connectivity of the corner (orthogonal) joint between adjacent panels. A series of tests were conducted on T-cap test articles, with and without a rod stiffener penetrating the T-cap web, under tension (pull-off) and bending loads. Three designs were tested, including the baseline design used in large-scale test articles. The baseline had only the manufacturing stitch row adjacent to the fillet at the base of the T-cap web. Two new designs added stitching rows to the T-cap web at either 0.5- or 1.0-inch spacing along the height of the web. Testing was conducted at NASA Langley Research Center to determine the behavior of the T-cap region resulting from the applied loading. Results show that stitching arrests the initial delamination failures so that the maximum strength capability exceeds the load at which the initial delaminations develop. However, it was seen that the added web stitching had very little effect on the initial delamination failure load, but actually decreased the initial delamination failure load for tension loading of test articles without a stiffener passing through the web. Additionally, the added web stitching only increased the maximum load capability by between 1% and 12.5%. The presence of the stiffener, however, did increase the initial and maximum loads for both tension and bending loading as compared to the stringerless baseline design. Based on the results of the few samples tested, the additional stitching in the T-cap web showed little advantage over the baseline design in terms of structural failure at the T-cap web/skin junction for the current test articles.

Diagnosing Students’ conception on atomic structure using open ended questions

NASA Astrophysics Data System (ADS)

Fitriza, Z.; Gazali, F.

2018-05-01

This study aims to diagnose students’ conception on atomic structure concepts using open ended questions. For this reason, a 7 items of assay test was administered to 135 senior high school students from different schools in West Sumatera. The data were collected using a an open ended test which is covering the concept used in the topic Atomic Structure. The open ended test of students’ conceptual was developed to identify the alternative conceptions that student might have regarding the concepts in Atomic Structure, to measure the level of students’ conceptions, and the way of students’ thinking concerning the concepts. The results showed that students find difficulties about some concepts of Atomic structure such as atom, atomic model, electron configuration, period and group.The result of this study illuminated the concepts to be underlined in developing teaching and learning approach concerning the topic of Atomic Structure.

The Analytical Pragmatic Structure of Procedural Due Process: A Framework for Inquiry in Administrative Decision Making.

ERIC Educational Resources Information Center

Fisher, James E.; Sealey, Ronald W.

The study describes the analytical pragmatic structure of concepts and applies this structure to the legal concept of procedural due process. This structure consists of form, purpose, content, and function. The study conclusions indicate that the structure of the concept of procedural due process, or any legal concept, is not the same as the…

Evolution of Structural Empowerment: Moving From Shared to Professional Governance.

PubMed

Clavelle, Joanne T; Porter O'Grady, Tim; Weston, Marla J; Verran, Joyce A

2016-06-01

The aim of this study is to describe the maturation of the concept of shared governance to professional governance as a framework for structural empowerment. An analysis of the literature and concept clarification of structural empowerment and shared governance demonstrate that the concept and attributes of shared governance have evolved toward professional governance. A comprehensive, deductive literature review and concept clarification of structural empowerment, shared governance, and related constructs was completed. The concept and practice of shared governance has matured to a concept of professional governance with the attributes of accountability, professional obligation, collateral relationships, and effective decision-making.

Design and evaluation of a foam-filled hat-stiffened panel concept for aircraft primary structural applications

NASA Technical Reports Server (NTRS)

Ambur, Damodar R.

1995-01-01

A structurally efficient hat-stiffened panel concept that utilizes a structural foam as stiffener core has been designed for aircraft primary structural applications. This stiffener concept utilizes a manufacturing process that can be adapted readily to grid-stiffened structural configurations which possess inherent damage tolerance characteristics due to their multiplicity of load paths. The foam-filled hat-stiffener concept in a prismatically stiffened panel configuration is more efficient than most other stiffened panel configurations in a load range that is typical for both fuselage and wing structures. The prismatically stiffened panel concept investigated here has been designed using AS4/3502 preimpregnated tape and Rohacell foam core and evaluated for its buckling and postbuckling behavior with and without low-speed impact damage. The results from single-stiffener and multi-stiffener specimens suggest that this structural concept responds to loading as anticipated and has good damage tolerance characteristics.

Elastomeric Structural Attachment Concepts for Aircraft Flap Noise Reduction - Challenges and Approaches to Hyperelastic Structural Modeling and Analysis

NASA Technical Reports Server (NTRS)

Sreekantamurthy, Thammaiah; Turner, Travis L.; Moore, James B.; Su, Ji

2014-01-01

Airframe noise is a significant part of the overall noise of transport aircraft during the approach and landing phases of flight. Airframe noise reduction is currently emphasized under the Environmentally Responsible Aviation (ERA) and Fixed Wing (FW) Project goals of NASA. A promising concept for trailing-edge-flap noise reduction is a flexible structural element or link that connects the side edges of the deployable flap to the adjacent main-wing structure. The proposed solution is distinguished by minimization of the span-wise extent of the structural link, thereby minimizing the aerodynamic load on the link structure at the expense of increased deformation requirement. Development of such a flexible structural link necessitated application of hyperelastic materials, atypical structural configurations and novel interface hardware. The resulting highly-deformable structural concept was termed the FLEXible Side Edge Link (FLEXSEL) concept. Prediction of atypical elastomeric deformation responses from detailed structural analysis was essential for evaluating feasible concepts that met the design constraints. The focus of this paper is to describe the many challenges encountered with hyperelastic finite element modeling and the nonlinear structural analysis of evolving FLEXSEL concepts. Detailed herein is the nonlinear analysis of FLEXSEL concepts that emerged during the project which include solid-section, foamcore, hollow, extended-span and pre-stressed concepts. Coupon-level analysis performed on elastomeric interface joints, which form a part of the FLEXSEL topology development, are also presented.

Using Concept Maps to Monitor Knowledge Structure Changes in a Science Classroom

NASA Astrophysics Data System (ADS)

Cook, Leah J.

The aim of this research is to determine what differences may exist in students' structural knowledge while using a variety of concept mapping assessments. A concept map can be used as an assessment which connects concepts in a knowledge domain. A single assessment may not be powerful enough to establish how students' new knowledge relates to prior knowledge. More research is needed to establish how various aspects of the concept mapping task influence the output of map creation by students. Using multiple concept maps and pre-instruction and post-instruction VNOS instruments during a 16-week semester, this study was designed to investigate the impact of concept map training and the impact of assessment design on the created maps. Also, this study was designed to determine what differences can be observed between expert and novice maps and if similarities and differences exist between concept maps and an open-ended assessment. Participants created individual maps and the maps were analyzed for structural complexity, overall structure, and content. The concept maps were then compared by their timing, design, and scores. The results indicate that concept mapping training does significantly impact the shape and structure complexity of the map created by students. Additionally, these data support that students should be frequently reminded of appropriate concept mapping skills and opportunities so that good mapping skills will be utilized. Changing the assessment design does appear to be able to impact the overall structure and complexity of created maps, while narrowing the content focus of the map does not necessarily restrict the overall structure or the complexity. Furthermore, significant differences in structural complexity were observed between novice and expert mappers. The fluctuations of NOS concepts identified in student created maps may suggest why some students were still confused or had incorrect conceptions of NOS, despite explicit and reflective instruction throughout the semester.

Integrated Composite Stiffener Structure (ICoSS) Concept for Planetary Entry Vehicles

NASA Technical Reports Server (NTRS)

Kellas, Sotiris

2016-01-01

Results from the design, manufacturing, and testing of a lightweight Integrated Composite Stiffened Structure (ICoSS) concept, intended for multi-mission planetary entry vehicles are presented. Tests from both component and full-scale tests for a typical Earth Entry Vehicle forward shell manufactured using the ICoSS concept are presented and advantages of the concept for the particular application of passive Earth Entry Vehicles over other structural concepts are discussed.

Concept Map Structure, Gender and Teaching Methods: An Investigation of Students' Science Learning

ERIC Educational Resources Information Center

Gerstner, Sabine; Bogner, Franz X.

2009-01-01

Background: This study deals with the application of concept mapping to the teaching and learning of a science topic with secondary school students in Germany. Purpose: The main research questions were: (1) Do different teaching approaches affect concept map structure or students' learning success? (2) Is the structure of concept maps influenced…

Approximation concepts for efficient structural synthesis

NASA Technical Reports Server (NTRS)

Schmit, L. A., Jr.; Miura, H.

1976-01-01

It is shown that efficient structural synthesis capabilities can be created by using approximation concepts to mesh finite element structural analysis methods with nonlinear mathematical programming techniques. The history of the application of mathematical programming techniques to structural design optimization problems is reviewed. Several rather general approximation concepts are described along with the technical foundations of the ACCESS 1 computer program, which implements several approximation concepts. A substantial collection of structural design problems involving truss and idealized wing structures is presented. It is concluded that since the basic ideas employed in creating the ACCESS 1 program are rather general, its successful development supports the contention that the introduction of approximation concepts will lead to the emergence of a new generation of practical and efficient, large scale, structural synthesis capabilities in which finite element analysis methods and mathematical programming algorithms will play a central role.

Structural efficiency studies of corrugated compression panels with curved caps and beaded webs

NASA Technical Reports Server (NTRS)

Davis, R. C.; Mills, C. T.; Prabhakaran, R.; Jackson, L. R.

1984-01-01

Curved cross-sectional elements are employed in structural concepts for minimum-mass compression panels. Corrugated panel concepts with curved caps and beaded webs are optimized by using a nonlinear mathematical programming procedure and a rigorous buckling analysis. These panel geometries are shown to have superior structural efficiencies compared with known concepts published in the literature. Fabrication of these efficient corrugation concepts became possible by advances made in the art of superplastically forming of metals. Results of the mass optimization studies of the concepts are presented as structural efficiency charts for axial compression.

Locating relevant patient information in electronic health record data using representations of clinical concepts and database structures.

PubMed

Pan, Xuequn; Cimino, James J

2014-01-01

Clinicians and clinical researchers often seek information in electronic health records (EHRs) that are relevant to some concept of interest, such as a disease or finding. The heterogeneous nature of EHRs can complicate retrieval, risking incomplete results. We frame this problem as the presence of two gaps: 1) a gap between clinical concepts and their representations in EHR data and 2) a gap between data representations and their locations within EHR data structures. We bridge these gaps with a knowledge structure that comprises relationships among clinical concepts (including concepts of interest and concepts that may be instantiated in EHR data) and relationships between clinical concepts and the database structures. We make use of available knowledge resources to develop a reproducible, scalable process for creating a knowledge base that can support automated query expansion from a clinical concept to all relevant EHR data.

Using concept mapping to evaluate knowledge structure in problem-based learning.

PubMed

Hung, Chia-Hui; Lin, Chen-Yung

2015-11-27

Many educational programs incorporate problem-based learning (PBL) to promote students' learning; however, the knowledge structure developed in PBL remains unclear. The aim of this study was to use concept mapping to generate an understanding of the use of PBL in the development of knowledge structures. Using a quasi-experimental study design, we employed concept mapping to illustrate the effects of PBL by examining the patterns of concepts and differences in the knowledge structures of students taught with and without a PBL approach. Fifty-two occupational therapy undergraduates were involved in the study and were randomly divided into PBL and control groups. The PBL group was given two case scenarios for small group discussion, while the control group continued with ordinary teaching and learning. Students were asked to make concept maps after being taught about knowledge structure. A descriptive analysis of the morphology of concept maps was conducted in order to compare the integration of the students' knowledge structures, and statistical analyses were done to understand the differences between groups. Three categories of concept maps were identified as follows: isolated, departmental, and integrated. The students in the control group constructed more isolated maps, while the students in the PBL group tended toward integrated mapping. Concept Relationships, Hierarchy Levels, and Cross Linkages in the concept maps were significantly greater in the PBL group; however, examples of concept maps did not differ significantly between the two groups. The data indicated that PBL had a strong effect on the acquisition and integration of knowledge. The important properties of PBL, including situational learning, problem spaces, and small group interactions, can help students to acquire more concepts, achieve an integrated knowledge structure, and enhance clinical reasoning.

Novel large deployable antenna backing structure concepts for foldable reflectors

NASA Astrophysics Data System (ADS)

Fraux, V.; Lawton, M.; Reveles, J. R.; You, Z.

2013-12-01

This paper describes a number of large deployable antenna (LDA) reflector structure concepts developed at EnerSys-ABSL. Furthermore, EnerSys-ABSL has confirmed the desire to build a breadboard demonstrator of a backing deployable structure for a foldable reflector in the diameter range of 4-9 m. As part of this project EnerSys-ABSL has explored five novel deployable structure concepts. This paper presents the top level definition of these concepts together with the requirements considered in the design and selection of the preferred candidate. These new concepts are described and then compared through a trade-off analysis to identify the most suitable concept that EnerSys-ABSL would like to consider for the breadboard demonstrator. Finally, the kinematics of the chosen concept is described in more detail and future steps in the development process are highlighted.

Advanced composites structural concepts and materials technologies for primary aircraft structures: Design/manufacturing concept assessment

NASA Technical Reports Server (NTRS)

Chu, Robert L.; Bayha, Tom D.; Davis, HU; Ingram, J. ED; Shukla, Jay G.

1992-01-01

Composite Wing and Fuselage Structural Design/Manufacturing Concepts have been developed and evaluated. Trade studies were performed to determine how well the concepts satisfy the program goals of 25 percent cost savings, 40 percent weight savings with aircraft resizing, and 50 percent part count reduction as compared to the aluminum Lockheed L-1011 baseline. The concepts developed using emerging technologies such as large scale resin transfer molding (RTM), automatic tow placed (ATP), braiding, out-of-autoclave and automated manufacturing processes for both thermoset and thermoplastic materials were evaluated for possible application in the design concepts. Trade studies were used to determine which concepts carry into the detailed design development subtask.

Advanced composite structural concepts and material technologies for primary aircraft structures

NASA Technical Reports Server (NTRS)

Jackson, Anthony

1991-01-01

Structural weight savings using advanced composites have been demonstrated for many years. Most military aircraft today use these materials extensively and Europe has taken the lead in their use in commercial aircraft primary structures. A major inhibiter to the use of advanced composites in the United States is cost. Material costs are high and will remain high relative to aluminum. The key therefore lies in the significant reduction in fabrication and assembly costs. The largest cost in most structures today is assembly. As part of the NASA Advanced Composite Technology Program, Lockheed Aeronautical Systems Company has a contract to explore and develop advanced structural and manufacturing concepts using advanced composites for transport aircraft. Wing and fuselage concepts and related trade studies are discussed. These concepts are intended to lower cost and weight through the use of innovative material forms, processes, structural configurations and minimization of parts. The approach to the trade studies and the downselect to the primary wing and fuselage concepts is detailed. The expectations for the development of these concepts is reviewed.

Coming To Know: The Role of the Concept Map--Mirror, Assistant, Master?

ERIC Educational Resources Information Center

McAleese, Ray

This paper explains the process of creating and managing concept maps, using reflection as a focus for its argument. Section 1, What is a Concept Map?, highlights the background and definition of concept mapping, explains how maps signify virtual conceptual structures, looks at structural knowledge, provides an example of a concept map, and…

A Multifunctional Hot Structure Heatshield Concept for Planetary Entry

NASA Technical Reports Server (NTRS)

Walker, Sandra P.; Daryabeigi, Kamran; Samareh, Jamshid A.; Wagner, Robert; Waters, Allen

2015-01-01

A multifunctional hot structure heatshield concept is being developed to provide technology enhancements with significant benefits compared to the current state-of-the-art heatshield technology. These benefits can potentially enable future planetary missions. The concept is unique in integrating the function of the thermal protection system with the primary load carrying structural component. An advanced carbon-carbon material system has been evaluated for the load carrying structure, which will be utilized on the outer surface of the heatshield, and thus will operate as a hot structure exposed to the severe aerodynamic heating associated with planetary entry. Flexible, highly efficient blanket insulation is sized for use underneath the hot structure to maintain required operational internal temperatures. The approach followed includes developing preliminary designs to demonstrate feasibility of the concept and benefits over a traditional, baseline design. Where prior work focused on a concept for an Earth entry vehicle, the current efforts presented here are focused on developing a generic heatshield model and performing a trade study for a Mars entry application. This trade study includes both structural and thermal evaluation. The results indicate that a hot structure concept is a feasible alternative to traditional heatshields and may offer advantages that can enable future entry missions.

Children's Self-Concepts as Related to Family Structure and Family Concept.

ERIC Educational Resources Information Center

Parish, Joycelyn G.; Parish, Thomas S.

1983-01-01

Surveyed 426 children from intact, divorced, and reconstituted families, who responded to the Personal Attribute Inventory for Children to evaluate their families and themselves. Results showed a significant association between children's self-concepts and both their family structure and family concepts. (JAC)

New concept of critical infrastructure strengthening

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

Gazizov, Talgat R.; Orlov, Pavel E.; Zabolotsky, Alexander M.

2016-06-08

Strengthening of critical infrastructure is considered. Modal reservation of electronics is proposed as a new concept of the strengthening. The concept combines a widely used cold backup and a recently proposed modal filtration. It makes electronics reliable as well as protected against electromagnetic interference, especially the ultra-wide band pulses. New printed circuit board structure is suggested for implementation of the proposed concept. Results of simulation in time and frequency domains are presented for the suggested structures. Considerable attenuation of dangerous excitations shows that the new concept and structure are promising.

Enrollment Management: An Introduction to Concepts and Structures

ERIC Educational Resources Information Center

Bontrager, Bob

2004-01-01

In the increasingly complex world of managing enrollments, success or failure hinges on building a solid foundation of concepts, structures, and strategies. This first of a two-part series reviews the core concepts and structural considerations that underlie successful enrollment management organizations. The purpose of this article is to…

Connecting Structure-Property and Structure-Function Relationships across the Disciplines of Chemistry and Biology: Exploring Student Perceptions.

PubMed

Kohn, Kathryn P; Underwood, Sonia M; Cooper, Melanie M

2018-06-01

While many university students take science courses in multiple disciplines, little is known about how they perceive common concepts from different disciplinary perspectives. Structure-property and structure-function relationships have long been considered important explanatory concepts in the disciplines of chemistry and biology, respectively. Fourteen university students concurrently enrolled in introductory chemistry and biology courses were interviewed to explore their perceptions regarding 1) the meaning of structure, properties, and function; 2) the presentation of these concepts in their courses; and 3) how these concepts might be related. Findings suggest that the concepts of structure and properties were interpreted similarly between chemistry and biology, but students more closely associated the discussion of structure-property relationships with their chemistry courses and structure-function with biology. Despite receiving little in the way of instructional support, nine students proposed a coherent conceptual relationship, indicating that structure determines properties, which determine function. Furthermore, students described ways in which they connected and benefited from their understanding. Though many students are prepared to make these connections, we would encourage instructors to engage in cross-disciplinary conversations to understand the shared goals and disciplinary distinctions regarding these important concepts in an effort to better support students unable to construct these connections for themselves.

Concept Mapping: A Graphical System for Understanding the Relationship between Concepts. ERIC Digest.

ERIC Educational Resources Information Center

Plotnick, Eric

This ERIC Digest discusses concept mapping, a technique for representing the structure of information visually. Concept mapping can be used to brainstorm, design complex structures, communicate complex ideas, aid learning by explicitly integrating new and old knowledge, and assess understanding or diagnose misunderstanding. Visual representation…

Structural Design of Ares V Interstage Composite Structure

NASA Technical Reports Server (NTRS)

Sleigh, David W.; Sreekantamurthy, Thammaiah; Kosareo, Daniel N.; Martin, Robert A.; Johnson, Theodore F.

2011-01-01

Preliminary and detailed design studies were performed to mature composite structural design concepts for the Ares V Interstage structure as a part of NASA s Advanced Composite Technologies Project. Aluminum honeycomb sandwich and hat-stiffened composite panel structural concepts were considered. The structural design and analysis studies were performed using HyperSizer design sizing software and MSC Nastran finite element analysis software. System-level design trade studies were carried out to predict weight and margins of safety for composite honeycomb-core sandwich and composite hat-stiffened skin design concepts. Details of both preliminary and detailed design studies are presented in the paper. For the range of loads and geometry considered in this work, the hat-stiffened designs were found to be approximately 11-16 percent lighter than the sandwich designs. A down-select process was used to choose the most favorable structural concept based on a set of figures of merit, and the honeycomb sandwich design was selected as the best concept based on advantages in manufacturing cost.

On the Concept of "Respiration": Biology Student Teachers' Cognitive Structures and Alternative Conceptions

ERIC Educational Resources Information Center

Kurt, Hakan; Ekici, Gulay; Aktas, Murat; Aksu, Ozlem

2013-01-01

In researches, the subject of respiration has been determined to be among subjects about whom participants from all educational levels struggle to form their cognitive structures and have many alternative conceptions. This research was carried out in order to determine biology student teachers' cognitive structures and alternative conceptions…

Study of metallic structural design concepts for an arrow wing supersonic cruise configuration

NASA Technical Reports Server (NTRS)

Turner, M. J.; Grande, D. L.

1977-01-01

A structural design study was made, to assess the relative merits of various metallic structural concepts and materials for an advanced supersonic aircraft cruising at Mach 2.7. Preliminary studies were made to ensure compliance of the configuration with general design criteria, integrate the propulsion system with the airframe, select structural concepts and materials, and define an efficient structural arrangement. An advanced computerized structural design system was used, in conjunction with a relatively large, complex finite element model, for detailed analysis and sizing of structural members to satisfy strength and flutter criteria. A baseline aircraft design was developed for assessment of current technology. Criteria, analysis methods, and results are presented. The effect on design methods of using the computerized structural design system was appraised, and recommendations are presented concerning further development of design tools, development of materials and structural concepts, and research on basic technology.

Evaluating the Factor Structure of "Self-Concept" in Children: A Cautionary Note

ERIC Educational Resources Information Center

Drummond, Robert J.; McIntire, Walter G.

1977-01-01

This article examines the factor structure of two measures of self-concept routinely used with elementary school children: the Coopersmith Self-Esteem Inventory and the Self-Concept and Motivation Inventory. (Author)

Magnetohydrodynamic (MHD) Magnet Modeling

DTIC Science & Technology

1979-06-01

Relationship /4 to Structural Teeth and Cold Bore Tube 56 Force Cý.mponents on Saddlc Winding 84 57 Quarter Section of Magnet nesign at Midplane 85 58...Graphite/Epoxy Filament Wound 184 A-2 Concept B - Boron /Aluminum Structure 186 A-3 Concept i - Graphite/Epoxy Structure 187 A-4 Initial Stress Analysis...Wound A-15 MHD Magnet Modeling Manufacturing Sequence 205 Concept B - Boron /Aluminum Structure A-16 MHD Magnet Modeling Manufacturing Sequence 206

Recent advances in convectively cooled engine and airframe structures for hypersonic flight

NASA Technical Reports Server (NTRS)

Kelly, H. N.; Wieting, A. R.; Shore, C. P.; Nowak, R. J.

1978-01-01

A hydrogen-cooled structure for a fixed-geometry, airframe-integrated scramjet is described. The thermal/structural problems, concepts, design features, and technological advances are applicable to a broad range of engines. Convectively cooled airframe structural concepts that have evolved from an extensive series of investigations, the technology developments that have led to these concepts, and the benefits that accrue from their use are discussed.

Research on the comparison of performance-based concept and force-based concept

NASA Astrophysics Data System (ADS)

Wu, Zeyu; Wang, Dongwei

2011-03-01

There are two ideologies about structure design: force-based concept and performance-based concept. Generally, if the structure operates during elastic stage, the two philosophies usually attain the same results. But beyond that stage, the shortage of force-based method is exposed, and the merit of performance-based is displayed. Pros and cons of each strategy are listed herein, and then which structure is best suitable to each method analyzed. At last, a real structure is evaluated by adaptive pushover method to verify that performance-based method is better than force-based method.

Structural Configuration Systems Analysis for Advanced Aircraft Fuselage Concepts

NASA Technical Reports Server (NTRS)

Mukhopadhyay, Vivek; Welstead, Jason R.; Quinlan, Jesse R.; Guynn, Mark D.

2016-01-01

Structural configuration analysis of an advanced aircraft fuselage concept is investigated. This concept is characterized by a double-bubble section fuselage with rear mounted engines. Based on lessons learned from structural systems analysis of unconventional aircraft, high-fidelity finite-element models (FEM) are developed for evaluating structural performance of three double-bubble section configurations. Structural sizing and stress analysis are applied for design improvement and weight reduction. Among the three double-bubble configurations, the double-D cross-section fuselage design was found to have a relatively lower structural weight. The structural FEM weights of these three double-bubble fuselage section concepts are also compared with several cylindrical fuselage models. Since these fuselage concepts are different in size, shape and material, the fuselage structural FEM weights are normalized by the corresponding passenger floor area for a relative comparison. This structural systems analysis indicates that an advanced composite double-D section fuselage may have a relative structural weight ratio advantage over a conventional aluminum fuselage. Ten commercial and conceptual aircraft fuselage structural weight estimates, which are empirically derived from the corresponding maximum takeoff gross weight, are also presented and compared with the FEM- based estimates for possible correlation. A conceptual full vehicle FEM model with a double-D fuselage is also developed for preliminary structural analysis and weight estimation.

Self-Concepts in Reading, Writing, Listening, and Speaking: A Multidimensional and Hierarchical Structure and Its Generalizability across Native and Foreign Languages

ERIC Educational Resources Information Center

Arens, A. Katrin; Jansen, Malte

2016-01-01

Academic self-concept has been conceptualized as a multidimensional and hierarchical construct. Previous research has mostly focused on its multidimensionality, distinguishing between verbal and mathematical self-concept domains, and only a few studies have examined the factorial structure within specific self-concept domains. The present study…

Development of a metal-clad advanced composite shear web design concept

NASA Technical Reports Server (NTRS)

Laakso, J. H.

1974-01-01

An advanced composite web concept was developed for potential application to the Space Shuttle Orbiter main engine thrust structure. The program consisted of design synthesis, analysis, detail design, element testing, and large scale component testing. A concept was sought that offered significant weight saving by the use of Boron/Epoxy (B/E) reinforced titanium plate structure. The desired concept was one that was practical and that utilized metal to efficiently improve structural reliability. The resulting development of a unique titanium-clad B/E shear web design concept is described. Three large scale components were fabricated and tested to demonstrate the performance of the concept: a titanium-clad plus or minus 45 deg B/E web laminate stiffened with vertical B/E reinforced aluminum stiffeners.

Arrow-wing supersonic cruise aircraft structural design concepts evaluation. Volume 3: Sections 12 through 14

NASA Technical Reports Server (NTRS)

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

1975-01-01

The design of an economically viable supersonic cruise aircraft requires the lowest attainable structural-mass fraction commensurate with the selected near-term structural material technology. To achieve this goal of minimum structural-mass fraction, various combinations of promising wing and fuselage primary structure were analyzed for the load-temperature environment applicable to the arrow wing configuration. This analysis was conducted in accordance with the design criteria specified and included extensive use of computer-aided analytical methods to screen the candidate concepts and select the most promising concepts for the in-depth structural analysis.

From isosuperatoms to isosupermolecules: new concepts in cluster science

NASA Astrophysics Data System (ADS)

Liu, Liren; Li, Pai; Yuan, Lan-Feng; Cheng, Longjiu; Yang, Jinlong

2016-06-01

As an extension of the superatom concept, a new concept ``isosuperatom'' is proposed, reflecting the physical phenomenon that a superatom cluster can take multiple geometrical structures with their electronic structures topologically invariant. The icosahedral and cuboctahedral Au135+ units in the Au25(SCH2CH2Ph)18-, Au23(SC6H11)16- and Au24(SAdm)16 nanoclusters are found to be examples of this concept. Furthermore, two isosuperatoms can combine to form a supermolecule. For example, the structure of the {Ag32(DPPE)5(SC6H4CF3)24}2- nanocluster can be understood well in terms of a Ag2212+ supermolecule formed by two Ag138+ isosuperatoms. On the next level of complexity, various combinations of isosuperatoms can lead to supermolecules with different geometrical structures but similar electronic structures, i.e., ``isosupermolecules''. We take two synthesized nanoclusters Au20(PPhpy2)10Cl42+ and Au30S(StBu)18 to illustrate two Au206+ isosupermolecules. The proposed concepts of isosuperatom and isosupermolecule significantly enrich the superatom concept, give a new framework for understanding a wide range of nanoclusters, and open a new door for designing assembled materials.As an extension of the superatom concept, a new concept ``isosuperatom'' is proposed, reflecting the physical phenomenon that a superatom cluster can take multiple geometrical structures with their electronic structures topologically invariant. The icosahedral and cuboctahedral Au135+ units in the Au25(SCH2CH2Ph)18-, Au23(SC6H11)16- and Au24(SAdm)16 nanoclusters are found to be examples of this concept. Furthermore, two isosuperatoms can combine to form a supermolecule. For example, the structure of the {Ag32(DPPE)5(SC6H4CF3)24}2- nanocluster can be understood well in terms of a Ag2212+ supermolecule formed by two Ag138+ isosuperatoms. On the next level of complexity, various combinations of isosuperatoms can lead to supermolecules with different geometrical structures but similar electronic structures, i.e., ``isosupermolecules''. We take two synthesized nanoclusters Au20(PPhpy2)10Cl42+ and Au30S(StBu)18 to illustrate two Au206+ isosupermolecules. The proposed concepts of isosuperatom and isosupermolecule significantly enrich the superatom concept, give a new framework for understanding a wide range of nanoclusters, and open a new door for designing assembled materials. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01998f

Using Concept Maps to Monitor Knowledge Structure Changes in a Science Classroom

ERIC Educational Resources Information Center

Cook, Leah J.

2017-01-01

The aim of this research is to determine what differences may exist in students' structural knowledge while using a variety of concept mapping assessments. A concept map can be used as an assessment which connects concepts in a knowledge domain. A single assessment may not be powerful enough to establish how students' new knowledge relates to…

Application of an ecological framework to examine barriers to the adoption of safer conception strategies by HIV-affected couples.

PubMed

Saleem, Haneefa T; Surkan, Pamela J; Kerrigan, Deanna; Kennedy, Caitlin E

2016-01-01

Safer conception interventions can significantly reduce the risk of horizontal HIV transmission between HIV-serodiscordant partners. However, prior to implementing safer conception interventions, it is essential to understand potential barriers to their adoption so that strategies can be developed to overcome these barriers. This paper examines potential barriers to the adoption of safer conception strategies by HIV-affected couples in Iringa, Tanzania using an ecological framework. We interviewed 30 HIV-positive women, 30 HIV-positive men and 30 health providers engaged in delivering HIV-related services. We also conducted direct observations at five health facilities. Findings suggest that there are multiple barriers to safer conception that operate at the individual, relational, environmental, structural, and super-structural levels. The barriers to safer conception identified are complex and interact across these levels. Barriers at the individual level included antiretroviral adherence, knowledge of HIV status, knowledge and acceptability of safer conception strategies, and poor nutrition. At the relational level, unplanned pregnancies, non-disclosure of status, gendered power dynamics within relationships, and patient-provider interactions posed a threat to safer conception. HIV stigma and distance to health facilities were environmental barriers to safer conception. At the structural level there were multiple barriers to safer conception, including limited safer conception policy guidelines for people living with HIV (PLHIV), lack of health provider training in safer conception strategies and preconception counseling for PLHIV, limited resources, and lack of integration of HIV and sexual and reproductive health services. Poverty and gender norms were super-structural factors that influenced and reinforced barriers to safer conception, which influenced and operated across different levels of the framework. Multi-level interventions are needed to ensure adoption of safer conception strategies and reduce the risk of HIV transmission between partners within HIV-serodiscordant couples.

Investigating the high school students' cognitive structures about the work concept

NASA Astrophysics Data System (ADS)

Tavukçuoǧlu, Erdem; Özcan, Özgür

2018-02-01

The purpose of this study is to determine the high school students' cognitive structures related to the concepts of work. The participants of the study were composed of the students enrolled in 11. and 12. class of an Anatolian high school in Turkey. The data were collected via word association test related to the key concept to determine the students' cognitive structures. The collected data were analyzed according to the content analysis method. In the data analysis process, we determined firstly the number of words, the number of answers and the semantic relations between the words written by students. The words having semantic connections were grouped under the same category. Thus, at the end of the study, high school students' cognitive structures and some alternative conceptions were determined related to concepts of work.

Using Self-Organizing Neural Network Map Combined with Ward's Clustering Algorithm for Visualization of Students' Cognitive Structural Models about Aliveness Concept

PubMed Central

Ugulu, Ilker; Aydin, Halil

2016-01-01

We propose an approach to clustering and visualization of students' cognitive structural models. We use the self-organizing map (SOM) combined with Ward's clustering to conduct cluster analysis. In the study carried out on 100 subjects, a conceptual understanding test consisting of open-ended questions was used as a data collection tool. The results of analyses indicated that students constructed the aliveness concept by associating it predominantly with human. Motion appeared as the most frequently associated term with the aliveness concept. The results suggest that the aliveness concept has been constructed using anthropocentric and animistic cognitive structures. In the next step, we used the data obtained from the conceptual understanding test for training the SOM. Consequently, we propose a visualization method about cognitive structure of the aliveness concept. PMID:26819579

Structural Performance of a Compressively Loaded Foam-Core Hat-Stiffened Textile Composite Panel

NASA Technical Reports Server (NTRS)

Ambur, Damodar R.; Dexter, Benson H.

1996-01-01

A structurally efficient hat-stiffened panel concept that utilizes a structural foam as a stiffener core material has been designed and developed for aircraft primary structural applications. This stiffener concept is fabricated from textile composite material forms with a resin transfer molding process. This foam-filled hat-stiffener concept is structurally more efficient than most other prismatically stiffened panel configurations in a load range that is typical for both fuselage and wing structures. The panel design is based on woven/stitched and braided graphite-fiber textile preforms, an epoxy resin system, and Rohacell foam core. The structural response of this panel design was evaluated for its buckling and postbuckling behavior with and without low-speed impact damage. The results from single-stiffener and multi-stiffener specimen tests suggest that this structural concept responds to loading as anticipated and has excellent damage tolerance characteristics compared to a similar panel design made from preimpregnated graphite-epoxy tape material.

Validation of a unique concept for a low-cost, lightweight space-deployable antenna structure

NASA Technical Reports Server (NTRS)

Freeland, R. E.; Bilyeu, G. D.; Veal, G. R.

1993-01-01

An experiment conducted in the framework of a NASA In-Space Technology Experiments Program based on a concept of inflatable deployable structures is described. The concept utilizes very low inflation pressure to maintain the required geometry on orbit and gravity-induced deflection of the structure precludes any meaningful ground-based demonstrations of functions performance. The experiment is aimed at validating and characterizing the mechanical functional performance of a 14-m-diameter inflatable deployable reflector antenna structure in the orbital operational environment. Results of the experiment are expected to significantly reduce the user risk associated with using large space-deployable antennas by demonstrating the functional performance of a concept that meets the criteria for low-cost, lightweight, and highly reliable space-deployable structures.

Crashworthy airframe design concepts: Fabrication and testing

NASA Technical Reports Server (NTRS)

Cronkhite, J. D.; Berry, V. L.

1982-01-01

Crashworthy floor concepts applicable to general aviation aircraft metal airframe structures were investigated. Initially several energy absorbing lower fuselage structure concepts were evaluated. Full scale floor sections representative of a twin engine, general aviation airplane lower fuselage structure were designed and fabricated. The floors featured an upper high strength platform with an energy absorbing, crushable structure underneath. Eighteen floors were fabricated that incorporated five different crushable subfloor concepts. The floors were then evaluated through static and dynamic testing. Computer programs NASTRAN and KRASH were used for the static and dynamic analysis of the floor section designs. Two twin engine airplane fuselages were modified to incorporate the most promising crashworthy floor sections for test evaluation.

An Analysis of Perceptions and Attitudes Toward the Concepts "Disabled" and "Handicapped" and the Effects of Pre-Structured Definition Upon the Concepts.

ERIC Educational Resources Information Center

Ianacone, Robert N.; Stodden, Robert A.

The semantic differential technique was used in a study involving 40 undergraduate trainees in the area of special education to analyze the concepts "disabled" and "handicapped" and the effects of structured knowledge or definition on the participants' perceptions of and attitudes toward the concepts. The Semantic differential consisted of bipolar…

Outer planet probe engineering model structural tests

NASA Technical Reports Server (NTRS)

Smittkamp, J. A.; Gustin, W. H.; Griffin, M. W.

1977-01-01

A series of proof of concept structural tests was performed on an engineering model of the Outer Planets Atmospheric Entry Probe. The tests consisted of pyrotechnic shock, dynamic and static loadings. The tests partially verified the structural concept.

Using Concept Mapping to Uncover Students' Knowledge Structures of Chemical Bonding Concepts

ERIC Educational Resources Information Center

Burrows, Nikita L.; Mooring, Suazette Reid

2015-01-01

General chemistry is the first undergraduate course in which students further develop their understanding of fundamental chemical concepts. Many of these fundamental topics highlight the numerous conceptual interconnections present in chemistry. However, many students possess incoherent knowledge structures regarding these topics. Therefore,…

Industrial approach to piezoelectric damping of large fighter aircraft components

NASA Astrophysics Data System (ADS)

Simpson, John; Schweiger, Johannes

1998-06-01

Different concepts to damp structural vibrations of the vertical tail of fighter aircraft are reported. The various requirements for a vertical tail bias an integrated approach for the design. Several active vibrations suppression concepts had been investigated during the preparatory phase of a research program shared by Daimler-Benz Aerospace Military Aircraft (Dasa), Daimler-Benz Forschung (DBF) and Deutsche Forschungsandstalt fuer Luftund Raumfahrt (DLR). Now in the main phase of the programme, four concepts were finally chosen: two concepts with aerodynamic control surfaces and two concepts with piezoelectric components. One piezo concept approach will be described rigorously, the other concepts are briefly addressed. In the Dasa concept, thin surface piezo actuators are set out carefully to flatten the dynamic portion of the combined static and dynamic maximum bending moment loading case directly in the shell structure. The second piezo concept by DLR involves pre-loaded lead zirconate titanate (PZT)-block actuators at host structure fixtures. To this end a research apparatus was designed and built as a full scale simplified fin box with carbon fiber reinformed plastic skins and an aluminium stringer-rib substructure restrained by relevant aircraft fixtures. It constitutes a benchmark 3D-structural impedance. The engineering design incorporates 7kg of PZT surface actuators. The structural system then should be excited to more than 15mm tip displacement amplitude. This prepares the final step to total A/C integration. Typical analysis methods using cyclic thermal analogies adapted to induced load levels are compared. Commercial approaches leading onto basic state space model interpretation wrt. actuator sizing and positioning, structural integrity constraints, FE-validation and testing are described. Both piezoelectric strategies are aimed at straight open-loop performance related to concept weight penalty and input electric power. The required actuators, power and integration are then enhanced to specification standards. An adapted qualification program plan is used to improve analytical read across, specifications, manufacturing decisions, handling requirements. The next research goals are outlined.

Structures, performance, benefit, cost study. [gas turbine engines

NASA Technical Reports Server (NTRS)

Feder, E.

1981-01-01

Aircraft engine structures were studied to identify the advanced structural technologies that would provide the most benefits to future aircraft operations. A series of studies identified engine systems with the greatest potential for improvements. Based on these studies, six advanced generic structural concepts were selected and conceptually designed. The benefits of each concept were quantitatively assessed in terms of thrust specific fuel consumption, weight, cost, maintenance cost, fuel burned and direct operating cost plus interest. The probability of success of each concept was also determined. The concepts were ranked and the three most promising were selected for further study which consisted of identifying and comprehensively outlining the advanced technologies required to develop these concepts for aircraft engine application. Analytic, fabrication, and test technology developments are required. The technology programs outlined emphasize the need to provide basic, fundamental understanding of technology to obtain the benefit goals.

Aggregating concept map data to investigate the knowledge of beginning CS students

NASA Astrophysics Data System (ADS)

Mühling, Andreas

2016-07-01

Concept maps have a long history in educational settings as a tool for teaching, learning, and assessing. As an assessment tool, they are predominantly used to extract the structural configuration of learners' knowledge. This article presents an investigation of the knowledge structures of a large group of beginning CS students. The investigation is based on a method that collects, aggregates, and automatically analyzes the concept maps of a group of learners as a whole, to identify common structural configurations and differences in the learners' knowledge. It shows that those students who have attended CS education in their secondary school life have, on average, configured their knowledge about typical core CS/OOP concepts differently. Also, artifacts of their particular CS curriculum are visible in their externalized knowledge. The data structures and analysis methods necessary for working with concept landscapes have been implemented as a GNU R package that is freely available.

Information-System Structure by Communication-Technology Concepts: A Cybernetic Model Approach.

ERIC Educational Resources Information Center

Reisig, Gerhard H. R.

1978-01-01

Presents the "Evidence-of-Existence" information system in which the structure is developed, with application of cybernetic concepts, as an isomorphic model in analogy to the system structure of communication technology. Three criteria of structuring are postulated: (1) source-channel-sink, with input-output characteristics, (2) filter-type…

Personal Constructions of Biological Concepts--The Repertory Grid Approach

ERIC Educational Resources Information Center

McCloughlin, Thomas J. J.; Matthews, Philip S. C.

2017-01-01

This work discusses repertory grid analysis as a tool for investigating the structures of students' representations of biological concepts. Repertory grid analysis provides the researcher with a variety of techniques that are not associated with standard methods of concept mapping for investigating conceptual structures. It can provide valuable…

Assessing Students' Accounting Knowledge: A Structural Approach.

ERIC Educational Resources Information Center

Boldt, Margaret N.

2001-01-01

Comparisons of students' representations of financial accounting concepts with the knowledge structures of experts were depicted using Pathfinder networks. This structural approach identified the level of students' understanding of concepts and knowledge gaps that need to be addressed. (SK)

Rough Evaluation Structure: Application of Rough Set Theory to Generate Simple Rules for Inconsistent Preference Relation

NASA Astrophysics Data System (ADS)

Gehrmann, Andreas; Nagai, Yoshimitsu; Yoshida, Osamu; Ishizu, Syohei

Since management decision-making becomes complex and preferences of the decision-maker frequently becomes inconsistent, multi-attribute decision-making problems were studied. To represent inconsistent preference relation, the concept of evaluation structure was introduced. We can generate simple rules to represent inconsistent preference relation by the evaluation structures. Further rough set theory for the preference relation was studied and the concept of approximation was introduced. One of our main aims of this paper is to introduce a concept of rough evaluation structure for representing inconsistent preference relation. We apply rough set theory to the evaluation structure, and develop a method for generating simple rules for inconsistent preference relations. In this paper, we introduce concepts of totally ordered information system, similarity class of preference relation, upper and lower approximation of preference relations. We also show the properties of rough evaluation structure and provide a simple example. As an application of rough evaluation structure, we analyze questionnaire survey of customer preferences about audio players.

Minimum accommodation for aerobrake assembly. Phase 2: Structural concepts for a lunar transfer vehicle aerobrake which can be assembled on orbit

NASA Technical Reports Server (NTRS)

Dorsey, John T.; Watson, Judith J.; Tutterow, Robin D.

1993-01-01

A multidisciplinary conceptual study was conducted to define a reusable lunar transfer vehicle (LTV) aerobrake which could be launched on a Space Shuttle of Titan 4 and assembled on orbit at Space Station Freedom. A major objective was to design an aerobrake, with integrated structure and thermal protection systems, which has a mass less than 20 percent (9040 lb) of the LTV lunar return mass. The aerobrake segmentation concepts, the structural concepts, a joint concept for assembly, and a structural design with analysis of the aerobrake are described. Results show that a 50-foot diameter LTV aerobrake can be designed for on-orbit assembly which will achieve the 20 percent mass budget.

An Efficient Analysis Methodology for Fluted-Core Composite Structures

NASA Technical Reports Server (NTRS)

Oremont, Leonard; Schultz, Marc R.

2012-01-01

The primary loading condition in launch-vehicle barrel sections is axial compression, and it is therefore important to understand the compression behavior of any structures, structural concepts, and materials considered in launch-vehicle designs. This understanding will necessarily come from a combination of test and analysis. However, certain potentially beneficial structures and structural concepts do not lend themselves to commonly used simplified analysis methods, and therefore innovative analysis methodologies must be developed if these structures and structural concepts are to be considered. This paper discusses such an analysis technique for the fluted-core sandwich composite structural concept. The presented technique is based on commercially available finite-element codes, and uses shell elements to capture behavior that would normally require solid elements to capture the detailed mechanical response of the structure. The shell thicknesses and offsets using this analysis technique are parameterized, and the parameters are adjusted through a heuristic procedure until this model matches the mechanical behavior of a more detailed shell-and-solid model. Additionally, the detailed shell-and-solid model can be strategically placed in a larger, global shell-only model to capture important local behavior. Comparisons between shell-only models, experiments, and more detailed shell-and-solid models show excellent agreement. The discussed analysis methodology, though only discussed in the context of fluted-core composites, is widely applicable to other concepts.

Connecting Structure-Property and Structure-Function Relationships across the Disciplines of Chemistry and Biology: Exploring Student Perceptions

ERIC Educational Resources Information Center

Kohn, Kathryn P.; Underwood, Sonia M.; Cooper, Melanie M.

2018-01-01

While many university students take science courses in multiple disciplines, little is known about how they perceive common concepts from different disciplinary perspectives. Structure-property and structure-function relationships have long been considered important explanatory concepts in the disciplines of chemistry and biology, respectively.…

Conceptual Hierarchies in a Flat Attractor Network

PubMed Central

O’Connor, Christopher M.; Cree, George S.; McRae, Ken

2009-01-01

The structure of people’s conceptual knowledge of concrete nouns has traditionally been viewed as hierarchical (Collins & Quillian, 1969). For example, superordinate concepts (vegetable) are assumed to reside at a higher level than basic-level concepts (carrot). A feature-based attractor network with a single layer of semantic features developed representations of both basic-level and superordinate concepts. No hierarchical structure was built into the network. In Experiment and Simulation 1, the graded structure of categories (typicality ratings) is accounted for by the flat attractor-network. Experiment and Simulation 2 show that, as with basic-level concepts, such a network predicts feature verification latencies for superordinate concepts (vegetable ). In Experiment and Simulation 3, counterintuitive results regarding the temporal dynamics of similarity in semantic priming are explained by the model. By treating both types of concepts the same in terms of representation, learning, and computations, the model provides new insights into semantic memory. PMID:19543434

The development of structural complexity in the child's concept of family: the effect of cognitive stage, sex, and intactness of family.

PubMed

Wedemeyer, N V; Bickhard, M H; Cooper, R G

1989-12-01

Twenty-eight boys and 28 girls at each of the Piagetian preoperational, concrete operational, and formal operational cognitive stages were given an interview focusing on their concepts of family. Half of each group were from intact families, and half were from divorced families. Interviews were scored for two structural aspects of the concept of family: conceptual level, and use of dimensions that structure the concept. The complexity of children's concepts was strongly related to cognitive stage and, to a lesser degree, to sex. Frequency of use of concept dimensions was strongly affected by general developmental level, though not specifically cognitive stage, and by intactness of family, but to a lesser degree by sex. Specific information is provided on the effect of these factors on perceptions of family composition, parental roles, and breadth of family activities.

Psychometric and Edumetric Validity of Dimensions of Geomorphological Knowledge Which Are Tapped by Concept Mapping.

ERIC Educational Resources Information Center

Hoz, Ron; Bowman, Dan; Chacham, Tova

1997-01-01

Students (N=14) in a geomorphology course took an objective geomorphology test, the tree construction task, and the Standardized Concept Structuring Analysis Technique (SConSAT) version of concept mapping. Results suggest that the SConSAT knowledge structure dimensions have moderate to good construct validity. Contains 82 references. (DDR)

A Structural Equation Modelling of the Academic Self-Concept Scale

ERIC Educational Resources Information Center

Matovu, Musa

2014-01-01

The study aimed at validating the academic self-concept scale by Liu and Wang (2005) in measuring academic self-concept among university students. Structural equation modelling was used to validate the scale which was composed of two subscales; academic confidence and academic effort. The study was conducted on university students; males and…

Physics Structure Analysis of Parallel Waves Concept of Physics Teacher Candidate

NASA Astrophysics Data System (ADS)

Sarwi, S.; Supardi, K. I.; Linuwih, S.

2017-04-01

The aim of this research was to find a parallel structure concept of wave physics and the factors that influence on the formation of parallel conceptions of physics teacher candidates. The method used qualitative research which types of cross-sectional design. These subjects were five of the third semester of basic physics and six of the fifth semester of wave course students. Data collection techniques used think aloud and written tests. Quantitative data were analysed with descriptive technique-percentage. The data analysis technique for belief and be aware of answers uses an explanatory analysis. Results of the research include: 1) the structure of the concept can be displayed through the illustration of a map containing the theoretical core, supplements the theory and phenomena that occur daily; 2) the trend of parallel conception of wave physics have been identified on the stationary waves, resonance of the sound and the propagation of transverse electromagnetic waves; 3) the influence on the parallel conception that reading textbooks less comprehensive and knowledge is partial understanding as forming the structure of the theory.

Space construction system analysis. Part 2: Space construction experiments concepts

NASA Technical Reports Server (NTRS)

Boddy, J. A.; Wiley, L. F.; Gimlich, G. W.; Greenberg, H. S.; Hart, R. J.; Lefever, A. E.; Lillenas, A. N.; Totah, R. S.

1980-01-01

Technology areas in the orbital assembly of large space structures are addressed. The areas included structures, remotely operated assembly techniques, and control and stabilization. Various large space structure design concepts are reviewed and their construction procedures and requirements are identified.

Concept-based query language approach to enterprise information systems

NASA Astrophysics Data System (ADS)

Niemi, Timo; Junkkari, Marko; Järvelin, Kalervo

2014-01-01

In enterprise information systems (EISs) it is necessary to model, integrate and compute very diverse data. In advanced EISs the stored data often are based both on structured (e.g. relational) and semi-structured (e.g. XML) data models. In addition, the ad hoc information needs of end-users may require the manipulation of data-oriented (structural), behavioural and deductive aspects of data. Contemporary languages capable of treating this kind of diversity suit only persons with good programming skills. In this paper we present a concept-oriented query language approach to manipulate this diversity so that the programming skill requirements are considerably reduced. In our query language, the features which need technical knowledge are hidden in application-specific concepts and structures. Therefore, users need not be aware of the underlying technology. Application-specific concepts and structures are represented by the modelling primitives of the extended RDOOM (relational deductive object-oriented modelling) which contains primitives for all crucial real world relationships (is-a relationship, part-of relationship, association), XML documents and views. Our query language also supports intensional and extensional-intensional queries, in addition to conventional extensional queries. In its query formulation, the end-user combines available application-specific concepts and structures through shared variables.

On the universal structure of human lexical semantics

PubMed Central

Sutton, Logan; Smith, Eric; Moore, Cristopher; Wilkins, Jon F.; Maddieson, Ian; Croft, William

2016-01-01

How universal is human conceptual structure? The way concepts are organized in the human brain may reflect distinct features of cultural, historical, and environmental background in addition to properties universal to human cognition. Semantics, or meaning expressed through language, provides indirect access to the underlying conceptual structure, but meaning is notoriously difficult to measure, let alone parameterize. Here, we provide an empirical measure of semantic proximity between concepts using cross-linguistic dictionaries to translate words to and from languages carefully selected to be representative of worldwide diversity. These translations reveal cases where a particular language uses a single “polysemous” word to express multiple concepts that another language represents using distinct words. We use the frequency of such polysemies linking two concepts as a measure of their semantic proximity and represent the pattern of these linkages by a weighted network. This network is highly structured: Certain concepts are far more prone to polysemy than others, and naturally interpretable clusters of closely related concepts emerge. Statistical analysis of the polysemies observed in a subset of the basic vocabulary shows that these structural properties are consistent across different language groups, and largely independent of geography, environment, and the presence or absence of a literary tradition. The methods developed here can be applied to any semantic domain to reveal the extent to which its conceptual structure is, similarly, a universal attribute of human cognition and language use. PMID:26831113

Structural Concepts Study of Non-circular Fuselage Configurations

NASA Technical Reports Server (NTRS)

Mukhopadhyay, Vivel

1996-01-01

A preliminary study of structural concepts for noncircular fuselage configurations is presented. For an unconventional flying-wing type aircraft, in which the fuselage is inside the wing, multiple fuselage bays with non-circular sections need to be considered. In a conventional circular fuselage section, internal pressure is carried efficiently by a thin skin via hoop tension. If the section is non-circular, internal pressure loads also induce large bending stresses. The structure must also withstand additional bending and compression loads from aerodynamic and gravitational forces. Flat and vaulted shell structural configurations for such an unconventional, non-circular pressurized fuselage of a large flying-wing were studied. A deep honeycomb sandwich-shell and a ribbed double-wall shell construction were considered. Combinations of these structural concepts were analyzed using both analytical and simple finite element models of isolated sections for a comparative conceptual study. Weight, stress, and deflection results were compared to identify a suitable configuration for detailed analyses. The flat sandwich-shell concept was found preferable to the vaulted shell concept due to its superior buckling stiffness. Vaulted double-skin ribbed shell configurations were found to be superior due to their weight savings, load diffusion, and fail-safe features. The vaulted double-skin ribbed shell structure concept was also analyzed for an integrated wing-fuselage finite element model. Additional problem areas such as wing-fuselage junction and pressure-bearing spar were identified.

Validation and structural analysis of the kinematics concept test

NASA Astrophysics Data System (ADS)

Lichtenberger, A.; Wagner, C.; Hofer, S. I.; Stern, E.; Vaterlaus, A.

2017-06-01

The kinematics concept test (KCT) is a multiple-choice test designed to evaluate students' conceptual understanding of kinematics at the high school level. The test comprises 49 multiple-choice items about velocity and acceleration, which are based on seven kinematic concepts and which make use of three different representations. In the first part of this article we describe the development and the validation process of the KCT. We applied the KCT to 338 Swiss high school students who attended traditional teaching in kinematics. We analyzed the response data to provide the psychometric properties of the test. In the second part we present the results of a structural analysis of the test. An exploratory factor analysis of 664 student answers finally uncovered the seven kinematics concepts as factors. However, the analysis revealed a hierarchical structure of concepts. At the higher level, mathematical concepts group together, and then split up into physics concepts at the lower level. Furthermore, students who seem to understand a concept in one representation have difficulties transferring the concept to similar problems in another representation. Both results have implications for teaching kinematics. First, teaching mathematical concepts beforehand might be beneficial for learning kinematics. Second, instructions have to be designed to teach students the change between different representations.

Preliminary Development of a Multifunctional Hot Structure Heat Shield

NASA Technical Reports Server (NTRS)

Walker, Sandra P.; Daryabeigi, Kamran; Samareh, Jamshid A.; Armand, Sasan C.; Perino, Scott V

2014-01-01

Development of a Multifunctional Hot Structure Heat Shield concept has initiated with the goal to provide advanced technology with significant benefits compared to the current state of the art heat shield technology. The concept is unique in integrating the function of the thermal protection system with the primary load carrying structural component. An advanced carbon-carbon material system has been evaluated for the load carrying structure, which will be utilized on the outer surface of the heat shield, and thus will operate as a hot structure exposed to the severe aerodynamic heating associated with planetary entry. Flexible, highly efficient blanket insulation has been sized for use underneath the hot structure to maintain desired internal temperatures. The approach was to develop a preliminary design to demonstrate feasibility of the concept. The preliminary results indicate that the concept has the potential to save both mass and volume with significantly less recession compared to traditional heat shield designs, and thus provide potential to enable new planetary missions.

Concepts and Objectives for Learning the Structure of English in Grades 7, 8, and 9. Report from the Project on Individually Guided Instruction in English Language, Composition, and Literature.

ERIC Educational Resources Information Center

Pooley, Robert C.; Golub, Lester S.

Emphasizing the behavioral and social aspects of language as a foundation for instruction, 16 concepts for learning the structure of English in grades 7-9 are outlined in an attempt to set down in logical order the basic concepts involved in the understanding of the English language. The concepts begin with a recognition of the social purposes of…

A Conceptual Aerospace Vehicle Structural System Modeling, Analysis and Design Process

NASA Technical Reports Server (NTRS)

Mukhopadhyay, Vivek

2007-01-01

A process for aerospace structural concept analysis and design is presented, with examples of a blended-wing-body fuselage, a multi-bubble fuselage concept, a notional crew exploration vehicle, and a high altitude long endurance aircraft. Aerospace vehicle structures must withstand all anticipated mission loads, yet must be designed to have optimal structural weight with the required safety margins. For a viable systems study of advanced concepts, these conflicting requirements must be imposed and analyzed early in the conceptual design cycle, preferably with a high degree of fidelity. In this design process, integrated multidisciplinary analysis tools are used in a collaborative engineering environment. First, parametric solid and surface models including the internal structural layout are developed for detailed finite element analyses. Multiple design scenarios are generated for analyzing several structural configurations and material alternatives. The structural stress, deflection, strain, and margins of safety distributions are visualized and the design is improved. Over several design cycles, the refined vehicle parts and assembly models are generated. The accumulated design data is used for the structural mass comparison and concept ranking. The present application focus on the blended-wing-body vehicle structure and advanced composite material are also discussed.

Identifying Atomic Structure as a Threshold Concept: Student Mental Models and Troublesomeness

ERIC Educational Resources Information Center

Park, Eun Jung; Light, Gregory

2009-01-01

Atomic theory or the nature of matter is a principal concept in science and science education. This has, however, been complicated by the difficulty students have in learning the concept and the subsequent construction of many alternative models. To understand better the conceptual barriers to learning atomic structure, this study explores the…

Using a Simulation to Illustrate Crosscutting Concepts through a Disease Model

ERIC Educational Resources Information Center

Bokor, Julie; Darwiche, Houda; Joseph, Drew

2015-01-01

Using Pompe disease as a context affords the opportunity for students to consider multiple biological concepts and embraces the Next Generation Science Standards Disciplinary Core Ideas Structure and Function (LS1.A) and Inheritance of Traits (LS3.A) as well as Crosscutting Concepts Structure and Function and Cause and Effect. These crosscutting…

"Adult" as a Concept for Young People Building Their Life Course

ERIC Educational Resources Information Center

Pavlenko, Ekaterina Sergeevna

2016-01-01

The structure of Russians' life course has never been studied in depth; the only exception is demographic studies regarding marital status and age at childbirth. Principles that define life trajectories should also be examined. The "adult" concept is one of a number of important concepts in the general structure of life planning. This…

The Self-Concept and Conjugal Loss: Evidence for Structural Change

ERIC Educational Resources Information Center

Montpetit, Mignon A.; Bergeman, C. S.; Bisconti, Toni L.

2010-01-01

The self-concept is often considered to be a personal resource that individuals may use to cope with life stressors, but little is known about how this entity might itself change in response to profound stress. The present study examines structural change in self-concept following conjugal loss in later life. Analyses were conducted on data…

Determination of Secondary School Students' Cognitive Structure, and Misconception in Ecological Concepts through Word Association Test

ERIC Educational Resources Information Center

Yücel, Elif Özata; Özkan, Mulis

2015-01-01

In this study, we determined cognitive structures and misconceptions about basic ecological concepts by using "word association" tests on secondary school students, age between 12-14 years. Eighty-nine students participated in this study. Before WAT was generated, basic ecological concepts that take place in the secondary science…

The microwave radiometer spacecraft: A design study

NASA Technical Reports Server (NTRS)

Wright, R. L. (Editor)

1981-01-01

A large passive microwave radiometer spacecraft with near all weather capability of monitoring soil moisture for global crop forecasting was designed. The design, emphasizing large space structures technology, characterized the mission hardware at the conceptual level in sufficient detail to identify enabling and pacing technologies. Mission and spacecraft requirements, design and structural concepts, electromagnetic concepts, and control concepts are addressed.

Morphing wing structure with controllable twist based on adaptive bending-twist coupling

NASA Astrophysics Data System (ADS)

Raither, Wolfram; Heymanns, Matthias; Bergamini, Andrea; Ermanni, Paolo

2013-06-01

A novel semi-passive morphing airfoil concept based on variable bending-twist coupling induced by adaptive shear center location and torsional stiffness is presented. Numerical parametric studies and upscaling show that the concept relying on smart materials permits effective twist control while offering the potential of being lightweight and energy efficient. By means of an experimental characterization of an adaptive beam and a scaled adaptive wing structure, effectiveness and producibility of the structural concept are demonstrated.

Structural Definition and Mass Estimation of Lunar Surface Habitats for the Lunar Architecture Team Phase 2 (LAT-2) Study

NASA Technical Reports Server (NTRS)

Dorsey, John T.; Wu, K, Chauncey; Smith, Russell W.

2008-01-01

The Lunar Architecture Team Phase 2 study defined and assessed architecture options for a Lunar Outpost at the Moon's South Pole. The Habitation Focus Element Team was responsible for developing concepts for all of the Habitats and pressurized logistics modules particular to each of the architectures, and defined the shapes, volumes and internal layouts considering human factors, surface operations and safety requirements, as well as Lander mass and volume constraints. The Structures Subsystem Team developed structural concepts, sizing estimates and mass estimates for the primary Habitat structure. In these studies, the primary structure was decomposed into a more detailed list of components to be sized to gain greater insight into concept mass contributors. Structural mass estimates were developed that captured the effect of major design parameters such as internal pressure load. Analytical and empirical equations were developed for each structural component identified. Over 20 different hard-shell, hybrid expandable and inflatable soft-shell Habitat and pressurized logistics module concepts were sized and compared to assess structural performance and efficiency during the study. Habitats were developed in three categories; Mini Habs that are removed from the Lander and placed on the Lunar surface, Monolithic habitats that remain on the Lander, and Habitats that are part of the Mobile Lander system. Each category of Habitat resulted in structural concepts with advantages and disadvantages. The same modular shell components could be used for the Mini Hab concept, maximizing commonality and minimizing development costs. Larger Habitats had higher volumetric mass efficiency and floor area than smaller Habitats (whose mass was dominated by fixed items such as domes and frames). Hybrid and pure expandable Habitat structures were very mass-efficient, but the structures technology is less mature, and the ability to efficiently package and deploy internal subsystems remains an open issue.

Relational, Structural, and Semantic Analysis of Graphical Representations and Concept Maps

ERIC Educational Resources Information Center

Ifenthaler, Dirk

2010-01-01

The demand for good instructional environments presupposes valid and reliable analytical instruments for educational research. This paper introduces the "SMD Technology" (Surface, Matching, Deep Structure), which measures relational, structural, and semantic levels of graphical representations and concept maps. The reliability and validity of the…

Low Cost Large Core Vehicle Structures Assessment

NASA Technical Reports Server (NTRS)

Hahn, Steven E.

1998-01-01

Boeing Information, Space, and Defense Systems executed a Low Cost Large Core Vehicle Structures Assessment (LCLCVSA) under contract to NASA Marshall Space Flight Center (MSFC) between November 1997 and March 1998. NASA is interested in a low-cost launch vehicle, code named Magnum, to place heavy payloads into low earth orbit for missions such as a manned mission to Mars, a Next Generation Space Telescope, a lunar-based telescope, the Air Force's proposed space based laser, and large commercial satellites. In this study, structural concepts with the potential to reduce fabrication costs were evaluated in application to the Magnum Launch Vehicle (MLV) and the Liquid Fly Back Booster (LFBB) shuttle upgrade program. Seventeen concepts were qualitatively evaluated to select four concepts for more in-depth study. The four structural concepts selected were: an aluminum-lithium monocoque structure, an aluminum-lithium machined isogrid structure, a unitized composite sandwich structure, and a unitized composite grid structure. These were compared against a baseline concept based on the Space Shuttle External Tank (ET) construction. It was found that unitized composite structures offer significant cost and weight benefits to MLV structures. The limited study of application to LFBB structures indicated lower, but still significant benefits. Technology and facilities development roadmaps to prepare the approaches studied for application to MLV and LFBB were constructed. It was found that the cost and schedule to develop these approaches were in line with both MLV and LFBB development schedules. Current Government and Boeing programs which address elements of the development of the technologies identified are underway. It is recommended that NASA devote resources in a timely fashion to address the specific elements related to MLV and LFBB structures.

Advanced Concepts in Structuring and Utilizing Local Advisory Councils and Craft Committees.

ERIC Educational Resources Information Center

Carroll, Richard E.

Adoption and implementation of advanced concepts in structuring and using a local advisory council and craft committees can result in significantly improved vocational education programs. The organizational structure of a vocational-technical school advisory council should be a vehicle that facilitates accomplishment of its prime function--to…

A Structured Model for Software Documentation.

ERIC Educational Resources Information Center

Swigger, Keith

The concept of "structured programming" was developed to facilitate software production, but it has not carried over to documentation design. Two concepts of structure are relevant to user documentation for computer programs. The first is based on programming techniques that emphasize decomposition of tasks into discrete modules, while the second…

Structures performance, benefit, cost-study

NASA Technical Reports Server (NTRS)

Woike, O. G.; Salemme, C.; Stearns, E.; Oritz, P.; Roberts, M. L.; Baughman, J. L.; Johnston, R. P.; Demel, H. F.; Stabrylla, R. G.; Coffinberry, G. A.

1981-01-01

New technology concepts and structural analysis development needs which could lead to improved life cycle cost for future high-bypass turbofans were studied. The NASA-GE energy efficient engine technology is used as a base to assess the concept benefits. Recommended programs are identified for attaining these generic structural and other beneficial technologies.

Evaluating the effect of tillage on soil structural properties using the pedostructure concept

USDA-ARS?s Scientific Manuscript database

The pedostructure (PS) concept is a physically-based method of soil characterization that defines a soil based on its structure and the relationship between structure and soil water behavior. There are fifteen unique pedostructure parameters that define the macropore and micropore soil water behavio...

Connections between Concepts Revealed by the Electronic Structure of Carbon Monoxide

ERIC Educational Resources Information Center

Liu, Ying; Liu, Bihui; Liu, Yue; Drew, Michael G. B.

2012-01-01

Different models for the electronic structure of carbon monoxide are suggested in influential textbooks. Therefore, this electronic structure offers an interesting subject in teaching because it can be used as an example to relate seemingly conflicting concepts. Understanding the connections between ostensibly different methods and between…

Moving And Working On Space Structures

NASA Technical Reports Server (NTRS)

Mclaughlin, Pat B.

1992-01-01

Clawlike device attaches boots to rails. Memorandum presents, in sketches and brief text, concept for boot-toe clip helping astronaut move about outside on structures being built at Space Station. Clip also helps astronaut maintain stable position at worksite. Concept adaptable to underwater work on such structures as offshore oil rigs.

Concept-Development of a Structure Supported Membrane for Deployable Space Applications - From Nature to Manufacture and Testing

NASA Technical Reports Server (NTRS)

Zander, Martin; Belvin, W. K.

2012-01-01

Current space applications of membrane structures include large area solar power arrays, solar sails, antennas, and numerous other large aperture devices like the solar shades of the new James Webb Space Telescope. These expandable structural systems, deployed in-orbit to achieve the desired geometry, are used to collect, reflect and/or transmit electromagnetic radiation. This work, a feasibility study supporting a diploma thesis, describes the systematic process for developing a biologically inspired concept for a structure supported (integrated) membrane, that features a rip stop principle, makes self-deployment possible and is part of an ultra-light weight space application. Novel manufacturing of membrane prototypes and test results are presented for the rip-stop concepts. Test data showed that the new membrane concept has a higher tear resistance than neat film of equivalent mass.

Lunar habitat concept employing the space shuttle external tank.

PubMed

King, C B; Butterfield, A J; Hypes, W D; Nealy, J E; Simonsen, L C

1990-01-01

The space shuttle external tank, which consists of a liquid oxygen tank, an intertank structure, and a liquid hydrogen tank, is an expendable structure used for approximately 8.5 min during each launch. A concept for outfitting the liquid oxygen tank-intertank unit for a 12-person lunar habitat is described. The concept utilizes existing structures and openings for both man and equipment access without compromising the structural integrity of the tank. Living quarters, instrumentation, environmental control and life support, thermal control, and propulsion systems are installed at Space Station Freedom. The unmanned habitat is then transported to low lunar orbit and autonomously soft landed on the lunar surface. Design studies indicate that this concept is feasible by the year 2000 with concurrent development of a space transfer vehicle and manned cargo lander for crew changeover and resupply.

On the universal structure of human lexical semantics

DOE PAGES

Youn, Hyejin; Sutton, Logan; Smith, Eric; ...

2016-02-01

How universal is human conceptual structure? The way concepts are organized in the human brain may reflect distinct features of cultural, historical, and environmental background in addition to properties universal to human cognition. Semantics, or meaning expressed through language, provides indirect access to the underlying conceptual structure, but meaning is notoriously difficult to measure, let alone parameterize. Here, we provide an empirical measure of semantic proximity between concepts using cross-linguistic dictionaries to translate words to and from languages carefully selected to be representative of worldwide diversity. These translations reveal cases where a particular language uses a single “polysemous” word tomore » express multiple concepts that another language represents using distinct words. We use the frequency of such polysemies linking two concepts as a measure of their semantic proximity and represent the pattern of these linkages by a weighted network. This network is highly structured: Certain concepts are far more prone to polysemy than others, and naturally interpretable clusters of closely related concepts emerge. Statistical analysis of the polysemies observed in a subset of the basic vocabulary shows that these structural properties are consistent across different language groups, and largely independent of geography, environment, and the presence or absence of a literary tradition. As a result, the methods developed here can be applied to any semantic domain to reveal the extent to which its conceptual structure is, similarly, a universal attribute of human cognition and language use.« less

On the universal structure of human lexical semantics

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

Youn, Hyejin; Sutton, Logan; Smith, Eric

How universal is human conceptual structure? The way concepts are organized in the human brain may reflect distinct features of cultural, historical, and environmental background in addition to properties universal to human cognition. Semantics, or meaning expressed through language, provides indirect access to the underlying conceptual structure, but meaning is notoriously difficult to measure, let alone parameterize. Here, we provide an empirical measure of semantic proximity between concepts using cross-linguistic dictionaries to translate words to and from languages carefully selected to be representative of worldwide diversity. These translations reveal cases where a particular language uses a single “polysemous” word tomore » express multiple concepts that another language represents using distinct words. We use the frequency of such polysemies linking two concepts as a measure of their semantic proximity and represent the pattern of these linkages by a weighted network. This network is highly structured: Certain concepts are far more prone to polysemy than others, and naturally interpretable clusters of closely related concepts emerge. Statistical analysis of the polysemies observed in a subset of the basic vocabulary shows that these structural properties are consistent across different language groups, and largely independent of geography, environment, and the presence or absence of a literary tradition. As a result, the methods developed here can be applied to any semantic domain to reveal the extent to which its conceptual structure is, similarly, a universal attribute of human cognition and language use.« less

The Cognitive Structures of Turkish Pre-Service Teachers in Relation to the Concept of Light

ERIC Educational Resources Information Center

Sadoglu, Gunay Palic

2016-01-01

As learning is a product of the interaction between certain concepts which are already present within an individual's mind, it is becoming increasingly important to determine the cognitive structures in relation to these concepts which are present within the minds of students. It has been said that the word association test, which is a technique…

What Happens to the Food We Eat? Children's Conceptions of the Structure and Function of the Digestive System.

ERIC Educational Resources Information Center

Teixeira, Francimar Martins

2000-01-01

Describes children's conceptions of the structure and function of the human digestive system based on an investigation carried out with children aged 4-10 (n=45). Finds that children possess biological knowledge as an independent knowledge domain from the age of four. Discusses acquisition of and barriers to scientific concepts related to human…

Universals and Specifics of Math Self-Concept, Math Self-Efficacy, and Math Anxiety across 41 PISA 2003 Participating Countries

ERIC Educational Resources Information Center

Lee, Jihyun

2009-01-01

The overarching goal of the present study is to investigate the factorial structure of three closely related constructs: math self-concept, math self-efficacy, and math anxiety. The factorial structure consisting of three factors, each representing math self-concept, math self-efficacy, and math anxiety, is supported in all 41 countries employed…

Examining Teaching of Professional Concepts in Teacher Training and Investigating Students' Cognitive Structures Regarding Professional Concepts

ERIC Educational Resources Information Center

Karakus, Memet; Karakus, Fatma

2017-01-01

The study aims to determine education faculty students' cognitive structures regarding professional concepts, and to reveal the views of the students and faculty members about conceptual teaching. The participants of the study, which was designed as a case study, were determined using the criterion sampling method. In the study, which was carried…

Non-Traditional Organizational Design Concepts

DTIC Science & Technology

1982-05-01

specialists benefit, for recognition ave. to ave. have associatelon with project; resembles job enrichment. 9 12 . Structure/concept Yes Synonym for program...provisions Little Wall (1980): Form of recognition is per- for recognition ceived by functional specialists ; resem- bles job enrichment. 12 ...Indirect reward to functional recognition specialists ; resembles job enrichment. 12 . Structure/concept No • S applied in the pub- lic sector 108 U

Undergraduate Students' Conceptions of and Approaches to Learning in Biology: A Study of Their Structural Models and Gender Differences

ERIC Educational Resources Information Center

Chiou, Guo-Li; Liang, Jyh-Chong; Tsai, Chin-Chung

2012-01-01

This study reports the findings of a study which examined the relationship between conceptions of learning and approaches to learning in biology. This study, which used structural equation modelling, also sorted to identify gender differences in the relationship. Two questionnaires, the Conceptions of Learning Biology (COLB) and the Approaches to…

High School Students' Epistemological Beliefs, Conceptions of Learning, and Self-Efficacy for Learning Biology: A Study of Their Structural Models

ERIC Educational Resources Information Center

Sadi, Özlem; Dagyar, Miray

2015-01-01

The current work reveals the data of the study which examines the relationships among epistemological beliefs, conceptions of learning, and self-efficacy for biology learning with the help of the Structural Equation Modeling. Three questionnaires, the Epistemological Beliefs, the Conceptions of Learning Biology and the Self-efficacy for Learning…

Study of structural design concepts for an arrow wing supersonic transport configuration, volume 1. Tasks 1 and 2

NASA Technical Reports Server (NTRS)

1976-01-01

A structural design study was made, based on a 1975 level of technology, to assess the relative merits of structural concepts and materials for an advanced supersonic transport cruising at Mach 2.7. Preliminary studies were made to insure compliance of the configuration with general design criteria, to integrate the propulsion system with the airframe, to select structural concepts and materials, and to define an efficient structural arrangement. An advanced computerized structural design system was used, in conjunction with a relatively large, complex finite element model, for detailed analysis and sizing of structural members to satisfy strength and flutter criteria. A baseline aircraft design was developed for assessment of current technology and for use in future studies of aerostructural trades, and application of advanced technology. Criteria, analysis methods, and results are presented.

Simplified bipartite concepts of functioning and disability recommended for interdisciplinary use of the ICF.

PubMed

Thyberg, Mikael; Arvidsson, Patrik; Thyberg, Ingrid; Nordenfelt, Lennart

2015-01-01

To argue for and propose bipartite concepts of functioning and disability, to tally with the structure of the ICF classification list, concepts of social models and clinical needs. The ICF concepts are discussed in relation to the history of ideas regarding disability concepts and the needs for such concepts in interdisciplinary rehabilitation. Bipartite concepts are presented; they refer to actual functioning, simply body functions/structures and participation, including functioning in standardized environments. Participation refers to actually performed "activities", with "activities" simply denoting things that people may do. Bipartite concepts are congruent with the ICF classification and the structure of social models of disability, suitable for clinical and interdisciplinary use and easy to understand. The issue of standardized environments represents a methodological issue rather than the conceptual issue of defining functioning and disability. An individual perspective on activity and activity limitations, i.e. the middle part of the tripartite ICF concept, is somewhat similar to concepts of traditional language that were regarded as too generalizing already in 1912, when the interactional concept of "disability in a social sense" was introduced in rehabilitation practices. Bipartite concepts of functioning and disability are recommended for interdisciplinary use of the ICF. The ICF classification is useful, but the ICF concept of activities in an individual perspective is confusing. We suggest a use of the term "activities" simply to denote things that people may do and "participation" to denote actually performed activities. Estimations of ability should be explicit about how they are related to environmental factors.

New virtual sonar and wireless sensor system concepts

NASA Astrophysics Data System (ADS)

Houston, B. H.; Bucaro, J. A.; Romano, A. J.

2004-05-01

Recently, exciting new sensor array concepts have been proposed which, if realized, could revolutionize how we approach surface mounted acoustic sensor systems for underwater vehicles. Two such schemes are so-called ``virtual sonar'' which is formulated around Helmholtz integral processing and ``wireless'' systems which transfer sensor information through radiated RF signals. The ``virtual sonar'' concept provides an interesting framework through which to combat the dilatory effects of the structure on surface mounted sensor systems including structure-borne vibration and variations in structure-backing impedance. The ``wireless'' concept would eliminate the necessity of a complex wiring or fiber-optic external network while minimizing vehicle penetrations. Such systems, however, would require a number of advances in sensor and RF waveguide technologies. In this presentation, we will discuss those sensor and sensor-related developments which are desired or required in order to make practical such new sensor system concepts, and we will present several underwater applications from the perspective of exploiting these new sonar concepts. [Work supported by ONR.

Survey of Key Concepts in Enactivist Theory and Methodology

ERIC Educational Resources Information Center

Reid, David A.; Mgombelo, Joyce

2015-01-01

This article discusses key concepts within enactivist writing, focussing especially on concepts involved in the enactivist description of cognition as embodied action: perceptually guided action, embodiment, and structural coupling through recurrent sensorimotor patterns. Other concepts on which these concepts depend are also discussed, including…

Pressure-actuated cellular structures.

PubMed

Pagitz, M; Lamacchia, E; Hol, J M A M

2012-03-01

Shape changing structures will play an important role in future engineering designs since rigid structures are usually only optimal for a small range of service conditions. Hence, a concept for reliable and energy-efficient morphing structures that possess a large strength to self-weight ratio would be widely applicable. We propose a novel concept for morphing structures that is inspired by the nastic movement of plants. The idea is to connect prismatic cells with tailored pentagonal and/or hexagonal cross sections such that the resulting cellular structure morphs into given target shapes for certain cell pressures. An efficient algorithm for computing equilibrium shapes as well as cross-sectional geometries is presented. The potential of this novel concept is demonstrated by several examples that range from a flagellum like propulsion device to a morphing aircraft wing.

Thermostructural analysis of three structural concepts for reusable space vehicles

NASA Technical Reports Server (NTRS)

Taylor, A. H.; Jackson, L. R.

1979-01-01

Three structural concepts are studied: (1) a state-of-the-art insulated aluminum skin-stringer structure; (2) a near-art insulated evacuated aluminum-alloy honeycomb structure; and (3) an advanced evacuated Rene 41 honeycomb hot structure. Each is evaluated for its thermostructural performance for each of the flight profiles (ascent, entry, and a recall or abort). Results indicate that (1) the state-of-the-art structure encounters negligible thermal stress; (2) the near-art structure has acceptable thermal stresses; and (3) the advanced structure will have thermal stress levels above the material allowables.

In-space research, technology and engineering experiments and Space Station

NASA Technical Reports Server (NTRS)

Tyson, Richard; Gartrell, Charles F.

1988-01-01

The NASA Space Station will serve as a technology research laboratory, a payload-servicing facility, and a large structure fabrication and assembly facility. Space structures research will encompass advanced structural concepts and their dynamics, advanced control concepts, sensors, and actuators. Experiments dealing with fluid management will gather data on such fundamentals as multiphase flow phenomena. As requirements for power systems and thermal management grow, experiments quantifying the performance of energy systems and thermal management concepts will be undertaken, together with expanded efforts in the fields of information systems, automation, and robotics.

Concept analysis of mentoring.

PubMed

2013-10-01

The purpose of a concept analysis is to examine the structure and function of a concept by defining its attributes and internal structure. Concept analysis can clarify an overused or vague concept and promote mutual understanding by providing a precise operational definition. Mentoring is a concept more fully used by other fields, such as business, than in nursing and may not always translate well for use in nursing. Therefore, clarifying the meaning of the existing concept of mentoring and developing an operational definition for use in nursing are aims of this concept analysis. Mentoring is broadly based and concentrates on developing areas such as career progression, scholarly achievements, and personal development. Mentoring relationships are based around developing reciprocity and accountability between each partner. Mentoring is seen related to transition in practice, role acquisition, and socialization, as a way to support new colleagues. Mentorship is related to nurses' success in nursing practice linked to professionalism, nursing quality improvement, and self-confidence.

Comparison of Knowledge Structures with the Pathfinder Scaling Algorithm.

ERIC Educational Resources Information Center

McGaghie, William C.

The cognitive structure of 13 concepts in pulmonary physiology was explored among 112 first-year medical students and among 32 faculty members in three different expertise groups in a knowledge representation study. Purposes were to assess the degree of agreement among faculty members, map students' concept structures, and compare the similarity…

Determining Science Student Teachers' Cognitive Structure on the Concept of "Food Chain"

ERIC Educational Resources Information Center

Çinar, Derya

2015-01-01

The current study aims to determine science student teachers' cognitive structure on the concept of food chain. Qualitative research method was applied in this study. Fallacies detected in the pre-service teachers' conceptual structures are believed to result in students' developing misconceptions in their future classes and will adversely affect…

Science Student Teachers' Cognitive Structure on the Concept of "Food Pyramid"

ERIC Educational Resources Information Center

Çinar, Derya

2016-01-01

The current study aims to determine science student teachers' cognitive structure on the concept of food pyramid. Qualitative research method was applied in this study. Fallacies detected in the pre-service teachers' conceptual structures are believed to result in students' developing misconceptions in their future classes and will adversely…

Physical Models Have Gender-Specific Effects on Student Understanding of Protein Structure-Function Relationships

ERIC Educational Resources Information Center

Forbes-Lorman, Robin M.; Harris, Michelle A.; Chang, Wesley S.; Dent, Erik W.; Nordheim, Erik V.; Franzen, Margaret A.

2016-01-01

Understanding how basic structural units influence function is identified as a foundational/core concept for undergraduate biological and biochemical literacy. It is essential for students to understand this concept at all size scales, but it is often more difficult for students to understand structure-function relationships at the molecular…

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…

Gender Fairness within the Force Concept Inventory

ERIC Educational Resources Information Center

Traxler, Adrienne; Henderson, Rachel; Stewart, John; Stewart, Gay; Papak, Alexis; Lindell, Rebecca

2018-01-01

Research on the test structure of the Force Concept Inventory (FCI) has largely ignored gender, and research on FCI gender effects (often reported as "gender gaps") has seldom interrogated the structure of the test. These rarely crossed streams of research leave open the possibility that the FCI may not be structurally valid across…

Description of New Inflatable/Rigidizable Hexapod Structure Testbed for Shape and Vibration Control

NASA Technical Reports Server (NTRS)

Adetona, O.; Keel, L. H.; Horta, L. G.; Cadogan, D. P.; Sapna, G. H.; Scarborough, S. E.

2002-01-01

Larger and more powerful space based instruments are needed to meet increasingly sophisticated scientific demand. To support this need, concepts for telescopes with apertures of 100 meters are being investigated, but the required technologies are not in hand today. Due to the capacity limits of launch vehicles, the idea of deploying, erecting, or inflating large structures in space is being considered. Recently, rigidization concepts of large inflatable structures have demonstrated the capability of weight reductions of up to 50% from current concepts with packaging efficiencies near 80%. One of the important aspects of inflatable structures is vibration mitigation and line-of-sight control. Such control tasks are possible only after actuators/sensors are properly integrated into a rigidizable concept. To study these issues, we have developed an inflatable/rigidizable hexapod structure testbed. The testbed integrates state of the art piezo-electric self-sensing actuators into an inflatable/rigidizable structure and a flat membrane reflector. Using this testbed, we plan to experimentally demonstrate achievable vibration and line-of-sight control. This paper contains a description of the testbed and an outline of the test plan.

Overview of an Advanced Hypersonic Structural Concept Test Program

NASA Technical Reports Server (NTRS)

Stephens, Craig A.; Hudson, Larry D.; Piazza, Anthony

2007-01-01

This viewgraph presentation provides an overview of hypersonics M&S advanced structural concepts development and experimental methods. The discussion on concepts development includes the background, task objectives, test plan, and current status of the C/SiC Ruddervator Subcomponent Test Article (RSTA). The discussion of experimental methods examines instrumentation needs, sensors of interest, and examples of ongoing efforts in the development of extreme environment sensors.

The self-concept and conjugal loss: evidence for structural change.

PubMed

Montpetit, Mignon A; Bergeman, C S; Bisconti, Toni L

2010-08-01

The self-concept is often considered to be a personal resource that individuals may use to cope with life stressors, but little is known about how this entity might itself change in response to profound stress. The present study examines structural change in self-concept following conjugal loss in later life. Analyses were conducted on data collected from 57 widows every 4 months over the first 2 years post-loss. The first objective was to explore the adequacy of an operational definition of the self-concept as a latent construct lying at the confluence of self-esteem, perceived environmental mastery, and optimism. Because confirmatory factor analysis (CFA) supported this theoretically based conceptualization, the second objective of the study was to model stability and change in the structure of the self-concept over the 2-year study period. Results suggested that there is both stability and change in the self-system during the adjustment to major life stress.

Mining Concept Maps to Understand University Students' Learning

ERIC Educational Resources Information Center

Yoo, Jin Soung; Cho, Moon-Heum

2012-01-01

Concept maps, visual representations of knowledge, are used in an educational context as a way to represent students' knowledge, and identify mental models of students; however there is a limitation of using concept mapping due to its difficulty to evaluate the concept maps. A concept map has a complex structure which is composed of concepts and…

Concept Mapping: A Critical Thinking Technique

ERIC Educational Resources Information Center

Harris, Charles M.; Zha, Shenghua

2013-01-01

Concept mapping, graphically depicting the structure of abstract concepts, is based on the observation that pictures and line drawings are often more easily comprehended than the words that represent an abstract concept. The efficacy of concept mapping for facilitating critical thinking was assessed in four sections of an introductory psychology…

On the monitoring and implications of growing damages caused by manufacturing defects in composite structures

NASA Astrophysics Data System (ADS)

Schagerl, M.; Viechtbauer, C.; Hörrmann, S.

2015-07-01

Damage tolerance is a classical safety concept for the design of aircraft structures. Basically, this approach considers possible damages in the structure, predicts the damage growth under applied loading conditions and predicts the following decrease of the structural strength. As a fundamental result the damage tolerance approach yields the maximum inspection interval, which is the time a damage grows from a detectable to a critical level. The above formulation of the damage tolerance safety concept targets on metallic structures where the damage is typically a simple fatigue crack. Fiber-reinforced polymers show a much more complex damage behavior, such as delaminationsin laminated composites. Moreover, progressive damage in composites is often initiated by manufacturing defects. The complex manufacturing processes for composite structures almost certainly yield parts with defects, e.g. pores in the matrix or undulations of fibers. From such defects growing damages may start after a certain time of operation. The demand to simplify or even avoid the inspection of composite structures has therefore led to a comeback of the traditional safe-life safety concept. The aim of the so-called safe-life flaw tolerance concept is a structure that is capable of carrying the static loads during operation, despite significant damages and after a representative fatigue load spectrum. A structure with this property does not need to be inspected, respectively monitored at all during its service life. However, its load carrying capability is thereby not fully utilized. This article presents the possible refinement of the state-of-the-art safe-life flaw tolerance concept for composite structures towards a damage tolerance approach considering also the influence of manufacturing defects on damage initiation and growth. Based on fundamental physical relations and experimental observations the challenges when developing damage growth and residual strength curves are discussed.

Exploring physics concepts among novice teachers through CMAP tools

NASA Astrophysics Data System (ADS)

Suprapto, N.; Suliyanah; Prahani, B. K.; Jauhariyah, M. N. R.; Admoko, S.

2018-03-01

Concept maps are graphical tools for organising, elaborating and representing knowledge. Through Cmap tools software, it can be explored the understanding and the hierarchical structuring of physics concepts among novice teachers. The software helps physics teachers indicated a physics context, focus questions, parking lots, cross-links, branching, hierarchy, and propositions. By using an exploratory quantitative study, a total 13-concept maps with different physics topics created by novice physics teachers were analysed. The main differences of scoring between lecturer and peer-teachers’ scoring were also illustrated. The study offered some implications, especially for physics educators to determine the hierarchical structure of the physics concepts, to construct a physics focus question, and to see how a concept in one domain of knowledge represented on the map is related to a concept in another domain shown on the map.

Development of rotorcraft interior noise control concepts. Phase 3: Development of noise control concepts

NASA Technical Reports Server (NTRS)

Yoerkie, Charles A.; Gintoli, P. J.; Ingraham, S. T.; Moore, J. A.

1986-01-01

The goal of this research is the understanding of helicopter internal noise mechanisms and the development, design, and testing of noise control concepts which will produce significant reductions in the acoustic environment to which passengers are exposed. The Phase 3 effort involved the identification and evaluation of current and advanced treatment concepts, including isolation of structure-borne paths. In addition, a plan was devised for the full-scale evaluation of an isolation concept. Specific objectives were as follows: (1) identification and characterization of various noise control concepts; (2) implementation of noise control concepts within the S-76 SEA (statistical energy analysis) model; (3) definition and evaluation of a preliminary acoustic isolation design to reduce structure-borne transmission of acoustic frequency main gearbox gear clash vibrations into the airframe; (4) formulation of a plan for the full-scale validation of the isolation concept; and (5) prediction of the cabin noise environment with various noise control concepts installed.

Autonomous Assembly of Modular Structures in Space and on Extraterrestrial Locations

NASA Astrophysics Data System (ADS)

Alhorn, Dean C.

2005-02-01

The new U.S. National Vision for Space Exploration requires many new enabling technologies to accomplish the goals of space commercialization and returning humans to the moon and extraterrestrial environments. Traditionally, flight elements are complete sub-systems requiring humans to complete the integration and assembly. These bulky structures also require the use of heavy launch vehicles to send the units to a desired location. This philosophy necessitates a high degree of safety, numerous space walks at a significant cost. Future space mission costs must be reduced and safety increased to reasonably achieve exploration goals. One proposed concept is the autonomous assembly of space structures. This concept is an affordable, reliable solution to in-space and extraterrestrial assembly. Assembly is autonomously performed when two components join after determining that specifications are correct. Local sensors continue monitor joint integrity post assembly, which is critical for safety and structural reliability. Achieving this concept requires a change in space structure design philosophy and the development of innovative technologies to perform autonomous assembly. Assembly of large space structures will require significant numbers of integrity sensors. Thus simple, low-cost sensors are integral to the success of this concept. This paper addresses these issues and proposes a novel concept for assembling space structures autonomously. Core technologies required to achieve in space assembly are presented. These core technologies are critical to the goal of utilizing space in a cost efficient and safe manner. Additionally, these novel technologies can be applied to other systems both on earth and extraterrestrial environments.

Autonomous Assembly of Modular Structures in Space and on Extraterrestrial Locations

NASA Technical Reports Server (NTRS)

Alhorn, Dean C.

2005-01-01

The new U.S. National Vision for Space Exploration requires many new enabling technologies to accomplish the goals of space commercialization and returning humans to the moon and extraterrestrial environments. Traditionally, flight elements are complete subsystems requiring humans to complete the integration and assembly. These bulky structures also require the use of heavy launch vehicles to send the units to a desired location. This philosophy necessitates a high degree of safety, numerous space walks at a significant cost. Future space mission costs must be reduced and safety increased to reasonably achieve exploration goals. One proposed concept is the autonomous assembly of space structures. This concept is an affordable, reliable solution to in-space and extraterrestrial assembly. Assembly is autonomously performed when two components join after determining that specifications are correct. Local sensors continue monitor joint integrity post assembly, which is critical for safety and structural reliability. Achieving this concept requires a change in space structure design philosophy and the development of innovative technologies to perform autonomous assembly. Assembly of large space structures will require significant numbers of integrity sensors. Thus simple, low-cost sensors are integral to the success of this concept. This paper addresses these issues and proposes a novel concept for assembling space structures autonomously. Core technologies required to achieve in space assembly are presented. These core technologies are critical to the goal of utilizing space in a cost efficient and safe manner. Additionally, these novel technologies can be applied to other systems both on earth and extraterrestrial environments.

A Logico-Structural, Worldview Analysis of the Interrelationship between Science Interest, Gender, and Concept of Nature.

ERIC Educational Resources Information Center

Cobern, William W.; And Others

The purpose of this research was to provide information about gender-related worldview structures, among college students, that can inform the instructional decision making process. Information was generated in a logico-structural investigation of the interrelationship of gender, interest in science, and concept of nature. The strength of the…

Development of Teaching Material Oxidation-Reduction Reactions through Four Steps Teaching Material Development (4S TMD)

NASA Astrophysics Data System (ADS)

Syamsuri, B. S.; Anwar, S.; Sumarna, O.

2017-09-01

This research aims to develop oxidation-reduction reactions (redox) teaching material used the Four Steps Teaching Material Development (4S TMD) method consists of four steps: selection, structuring, characterization and didactical reduction. This paper is the first part of the development of teaching material that includes selection and structuring steps. At the selection step, the development of teaching material begins with the development concept of redox based on curriculum demands, then the development of fundamental concepts sourced from the international textbook, and last is the development of values or skills can be integrated with redox concepts. The results of this selection step are the subject matter of the redox concept and values can be integrated with it. In the structuring step was developed concept map that provide on the relationship between redox concepts; Macro structure that guide systematic on the writing of teaching material; And multiple representations which are the development of teaching material that connection between macroscopic, submicroscopic, and symbolic level representations. The result of the two steps in this first part of the study produced a draft of teaching material. Evaluation of the draft of teaching material is done by an expert lecturer in the field of chemical education to assess the feasibility of teaching material.

Identification and Assessment of Taiwanese Children's Conceptions of Learning Mathematics

ERIC Educational Resources Information Center

Chiu, Mei-Shiu

2012-01-01

The aim of the present study was to identify children's conceptions of learning mathematics and to assess the identified conceptions. Children's conceptions are identified by interviewing 73 grade 5 students in Taiwan. The interviews are analyzed using qualitative data analysis methods, which results in a structure of 5 major conceptions, each…

Constructing Concept Maps to Encourage Meaningful Learning in Science Classroom

ERIC Educational Resources Information Center

Akcay, Hakan

2017-01-01

The purpose of this activity is to demonstrate science teaching and assessing what is learned via using concept maps. Concept mapping is a technique for visually representing the structure of information. Concept mapping allows students to understand the relationships between concepts of science by creating a visual map of the connections. Concept…

Analysis and Test of Repair Concepts for a Carbon-Rod Reinforced Laminate

NASA Technical Reports Server (NTRS)

Baker, Donald J.; Rousseau, Carl Q.

2000-01-01

The use of pultruded carbon-epoxy rods for the reinforcement of composite laminates in some structures results in an efficient structural concept. The results of an analytical and experimental investigation of repair concepts of completely severed carbon-epoxy rods is presented. Three repair concepts are considered: (a) bonded repair with outside moldline and inside moldline doublers; (b) bonded repair with fasteners, and (c) bonded repair with outside moldline doubler only. The stiffness of the repairs was matched with the stiffness of the baseline specimen. The failure strains for the bonded repair with fasteners and the bonded repair with an outside moldline doubler exceeded a target design strain set for the repair concepts.

A new concept in telescope design SIC as the only material for mirrors and structure

NASA Astrophysics Data System (ADS)

Fruit, Michel; Antoine, Pascal; Bougoin, Michel

2018-04-01

This paper, "A new concept in telescope design SIC as the only material for mirrors and structure," was presented as part of International Conference on Space Optics—ICSO 1997, held in Toulouse, France.

Structured feedback on students' concept maps: the proverbial path to learning?

PubMed

Joseph, Conran; Conradsson, David; Nilsson Wikmar, Lena; Rowe, Michael

2017-05-25

Good conceptual knowledge is an essential requirement for health professions students, in that they are required to apply concepts learned in the classroom to a variety of different contexts. However, the use of traditional methods of assessment limits the educator's ability to correct students' conceptual knowledge prior to altering the educational context. Concept mapping (CM) is an educational tool for evaluating conceptual knowledge, but little is known about its use in facilitating the development of richer knowledge frameworks. In addition, structured feedback has the potential to develop good conceptual knowledge. The purpose of this study was to use Kinchin's criteria to assess the impact of structured feedback on the graphical complexity of CM's by observing the development of richer knowledge frameworks. Fifty-eight physiotherapy students created CM's targeting the integration of two knowledge domains within a case-based teaching paradigm. Each student received one round of structured feedback that addressed correction, reinforcement, forensic diagnosis, benchmarking, and longitudinal development on their CM's prior to the final submission. The concept maps were categorized according to Kinchin's criteria as either Spoke, Chain or Net representations, and then evaluated against defined traits of meaningful learning. The inter-rater reliability of categorizing CM's was good. Pre-feedback CM's were predominantly Chain structures (57%), with Net structures appearing least often. There was a significant reduction of the basic Spoke- structured CMs (P = 0.002) and a significant increase of Net-structured maps (P < 0.001) at the final evaluation (post-feedback). Changes in structural complexity of CMs appeared to be indicative of broader knowledge frameworks as assessed against the meaningful learning traits. Feedback on CM's seemed to have contributed towards improving conceptual knowledge and correcting naive conceptions of related knowledge. Educators in medical education could therefore consider using CM's to target individual student development.

Modelling students' knowledge organisation: Genealogical conceptual networks

NASA Astrophysics Data System (ADS)

Koponen, Ismo T.; Nousiainen, Maija

2018-04-01

Learning scientific knowledge is largely based on understanding what are its key concepts and how they are related. The relational structure of concepts also affects how concepts are introduced in teaching scientific knowledge. We model here how students organise their knowledge when they represent their understanding of how physics concepts are related. The model is based on assumptions that students use simple basic linking-motifs in introducing new concepts and mostly relate them to concepts that were introduced a few steps earlier, i.e. following a genealogical ordering. The resulting genealogical networks have relatively high local clustering coefficients of nodes but otherwise resemble networks obtained with an identical degree distribution of nodes but with random linking between them (i.e. the configuration-model). However, a few key nodes having a special structural role emerge and these nodes have a higher than average communicability betweenness centralities. These features agree with the empirically found properties of students' concept networks.

Dual methods and approximation concepts in structural synthesis

NASA Technical Reports Server (NTRS)

Fleury, C.; Schmit, L. A., Jr.

1980-01-01

Approximation concepts and dual method algorithms are combined to create a method for minimum weight design of structural systems. Approximation concepts convert the basic mathematical programming statement of the structural synthesis problem into a sequence of explicit primal problems of separable form. These problems are solved by constructing explicit dual functions, which are maximized subject to nonnegativity constraints on the dual variables. It is shown that the joining together of approximation concepts and dual methods can be viewed as a generalized optimality criteria approach. The dual method is successfully extended to deal with pure discrete and mixed continuous-discrete design variable problems. The power of the method presented is illustrated with numerical results for example problems, including a metallic swept wing and a thin delta wing with fiber composite skins.

Structural Design and Sizing of a Metallic Cryotank Concept

NASA Technical Reports Server (NTRS)

Sleight, David W.; Martin, Robert A.; Johnson, Theodore F.

2013-01-01

This paper presents the structural design and sizing details of a 33-foot (10 m) metallic cryotank concept used as the reference design to compare with the composite cryotank concepts developed by industry as part of NASA s Composite Cryotank Technology Development (CCTD) Project. The structural design methodology and analysis results for the metallic cryotank concept are reported in the paper. The paper describes the details of the metallic cryotank sizing assumptions for the baseline and reference tank designs. In particular, the paper discusses the details of the cryotank weld land design and analyses performed to obtain a reduced weight metallic cryotank design using current materials and manufacturing techniques. The paper also discusses advanced manufacturing techniques to spin-form the cryotank domes and compares the potential mass savings to current friction stir-welded technology.

University Students' Knowledge Structures and Informal Reasoning on the Use of Genetically Modified Foods: Multidimensional Analyses

NASA Astrophysics Data System (ADS)

Wu, Ying-Tien

2013-10-01

This study aims to provide insights into the role of learners' knowledge structures about a socio-scientific issue (SSI) in their informal reasoning on the issue. A total of 42 non-science major university students' knowledge structures and informal reasoning were assessed with multidimensional analyses. With both qualitative and quantitative analyses, this study revealed that those students with more extended and better-organized knowledge structures, as well as those who more frequently used higher-order information processing modes, were more oriented towards achieving a higher-level informal reasoning quality. The regression analyses further showed that the "richness" of the students' knowledge structures explained 25 % of the variation in their rebuttal construction, an important indicator of reasoning quality, indicating the significance of the role of students' sophisticated knowledge structure in SSI reasoning. Besides, this study also provides some initial evidence for the significant role of the "core" concept within one's knowledge structure in one's SSI reasoning. The findings in this study suggest that, in SSI-based instruction, science instructors should try to identify students' core concepts within their prior knowledge regarding the SSI, and then they should try to guide students to construct and structure relevant concepts or ideas regarding the SSI based on their core concepts. Thus, students could obtain extended and well-organized knowledge structures, which would then help them achieve better learning transfer in dealing with SSIs.

LTA structures and materials technology

NASA Technical Reports Server (NTRS)

Mayer, N. J.

1975-01-01

The state-of-the-art concerning structures and materials technology is reviewed. It is shown that many present materials developments resulting from balloon and aircraft research programs can be applied to new concepts in LTA vehicles. Both buoyant and semi-buoyant vehicles utilize similar approaches to solving structural problems and could involve pressurized non-rigid and unpressurized rigid structures. System designs common to both and vital to structural integrity include much of the past technology as well. Further research is needed in determination of structural loads, especially in future design concepts.

Large space erectable structures - building block structures study

NASA Technical Reports Server (NTRS)

Armstrong, W. H.; Skoumal, D. E.; Straayer, J. W.

1977-01-01

A modular planar truss structure and a long slender boom concept identified as building block approaches to construction of large spacecraft configurations are described. The concepts are compatible in weight and volume goals with the Space Transportation System, use standard structural units, and represent high on-orbit productivity in terms of structural area or beam length. Results of structural trade studies involving static and dynamic analyses of a single module and rigid body deployment analyses to assess kinetics and kinematics of automatic deployment of the building block modules are presented.

Conceptual Design and Structural Optimization of NASA Environmentally Responsible Aviation (ERA) Hybrid Wing Body Aircraft

NASA Technical Reports Server (NTRS)

Quinlan, Jesse R.; Gern, Frank H.

2016-01-01

Simultaneously achieving the fuel consumption and noise reduction goals set forth by NASA's Environmentally Responsible Aviation (ERA) project requires innovative and unconventional aircraft concepts. In response, advanced hybrid wing body (HWB) aircraft concepts have been proposed and analyzed as a means of meeting these objectives. For the current study, several HWB concepts were analyzed using the Hybrid wing body Conceptual Design and structural optimization (HCDstruct) analysis code. HCDstruct is a medium-fidelity finite element based conceptual design and structural optimization tool developed to fill the critical analysis gap existing between lower order structural sizing approaches and detailed, often finite element based sizing methods for HWB aircraft concepts. Whereas prior versions of the tool used a half-model approach in building the representative finite element model, a full wing-tip-to-wing-tip modeling capability was recently added to HCDstruct, which alleviated the symmetry constraints at the model centerline in place of a free-flying model and allowed for more realistic center body, aft body, and wing loading and trim response. The latest version of HCDstruct was applied to two ERA reference cases, including the Boeing Open Rotor Engine Integration On an HWB (OREIO) concept and the Boeing ERA-0009H1 concept, and results agreed favorably with detailed Boeing design data and related Flight Optimization System (FLOPS) analyses. Following these benchmark cases, HCDstruct was used to size NASA's ERA HWB concepts and to perform a related scaling study.

Satellite power systems (SPS) concept definition study. Volume 2, part 1: System engineering

NASA Technical Reports Server (NTRS)

Hanley, G. M.

1980-01-01

Top level trade studies are presented, including comparison of solid state and klystron concepts, higher concentration on the solar cells, composite and aluminum structure, and several variations to the reference concept. Detailed trade studies are presented in each of the subsystem areas (solar array, power distribution, structures, thermal control, attitude control and stationkeeping, microwave transmission, and ground receiving station). A description of the selected point design is also presented.

From surprise to cognition: Some effects of the structure of C.A.L. simulation programs on the cognitive and scientific activities of young adults

NASA Astrophysics Data System (ADS)

Dicker, R. J.

The main objective of this thesis is to describe the effect on cognition of the structure of CAL simulation programs used, in science teaching. Four programs simulating a pond ecosystem were written so as to present a simulation model and to assist in cognition in different ways. Various clinically detailed methods of describing learning were developed and tried including concept maps which were found to be sammative rather than formative descriptions of learning, and to be ambiguous) and hierarchical structures (which were found to be difficult to produce). Fran these concept maps and hierarchical structures I developed my Interaction Model of Learning which can be used to describe the chronological events concerned with cognition. Using the Interaction Model, the nature of cognition and the effect that CAL program structure has on this process is described. Various scenarios are presented as a means of showing the possible effects of program structure on learning. Four forms of concept learning activity and their relationship to learning valid and alternative conceptions are described. The findings from the study are particularly related to the work of Driver (1983), Marton (1976) and Entwistle (1981).

Business Management Concept Areas for Two-Year Postsecondary Institutions

ERIC Educational Resources Information Center

Gentry, Lee; Gentry, Eileen

1978-01-01

A core of educational concepts in business ownership and management for two-year postsecondary institutions is outlined: economic systems, economic decisionmaking, organizational structure, management principles, marketing factors, accounting, legal obligations, financial structure, risk-taking and insurance, taxes, data processing, and social…

Chicano Alternative Education.

ERIC Educational Resources Information Center

Galicia, H. Homero; Almaguer, Clementina

Alternative schooling is challenging some basic notions of curriculum, operation, and structure of traditional schools; it is not challenging the basic concept of schooling. Chicano alternative education, an elusive concept, lacks a precise definition. Chicano alternative schools reflect a vast diversity in structure, focus, and goals. The Chicano…

The method of abstraction in the design of databases and the interoperability

NASA Astrophysics Data System (ADS)

Yakovlev, Nikolay

2018-03-01

When designing the database structure oriented to the contents of indicators presented in the documents and communications subject area. First, the method of abstraction is applied by expansion of the indices of new, artificially constructed abstract concepts. The use of abstract concepts allows to avoid registration of relations many-to-many. For this reason, when built using abstract concepts, demonstrate greater stability in the processes. The example abstract concepts to address structure - a unique house number. Second, the method of abstraction can be used in the transformation of concepts by omitting some attributes that are unnecessary for solving certain classes of problems. Data processing associated with the amended concepts is more simple without losing the possibility of solving the considered classes of problems. For example, the concept "street" loses the binding to the land. The content of the modified concept of "street" are only the relations of the houses to the declared name. For most accounting tasks and ensure communication is enough.

Structures for the 3rd Generation Reusable Concept Vehicle

NASA Technical Reports Server (NTRS)

Hrinda, Glenn A.

2001-01-01

A major goal of NASA is to create an advance space transportation system that provides a safe, affordable highway through the air and into space. The long-term plans are to reduce the risk of crew loss to 1 in 1,000,000 missions and reduce the cost of Low-Earth Orbit by a factor of 100 from today's costs. A third generation reusable concept vehicle (RCV) was developed to assess technologies required to meet NASA's space access goals. The vehicle will launch from Cape Kennedy carrying a 25,000 lb. payload to the International Space Station (ISS). The system is an air breathing launch vehicle (ABLV) hypersonic lifting body with rockets and uses triple point hydrogen and liquid oxygen propellant. The focus of this paper is on the structural concepts and analysis methods used in developing the third generation reusable launch vehicle (RLV). Member sizes, concepts and material selections will be discussed as well as analysis methods used in optimizing the structure. Analysis based on the HyperSizer structural sizing software will be discussed. Design trades required to optimize structural weight will be presented.

Virtual reality training improves students' knowledge structures of medical concepts.

PubMed

Stevens, Susan M; Goldsmith, Timothy E; Summers, Kenneth L; Sherstyuk, Andrei; Kihmm, Kathleen; Holten, James R; Davis, Christopher; Speitel, Daniel; Maris, Christina; Stewart, Randall; Wilks, David; Saland, Linda; Wax, Diane; Panaiotis; Saiki, Stanley; Alverson, Dale; Caudell, Thomas P

2005-01-01

Virtual environments can provide training that is difficult to achieve under normal circumstances. Medical students can work on high-risk cases in a realistic, time-critical environment, where students practice skills in a cognitively demanding and emotionally compelling situation. Research from cognitive science has shown that as students acquire domain expertise, their semantic organization of core domain concepts become more similar to those of an expert's. In the current study, we hypothesized that students' knowledge structures would become more expert-like as a result of their diagnosing and treating a patient experiencing a hematoma within a virtual environment. Forty-eight medical students diagnosed and treated a hematoma case within a fully immersed virtual environment. Student's semantic organization of 25 case-related concepts was assessed prior to and after training. Students' knowledge structures became more integrated and similar to an expert knowledge structure of the concepts as a result of the learning experience. The methods used here for eliciting, representing, and evaluating knowledge structures offer a sensitive and objective means for evaluating student learning in virtual environments and medical simulations.

Concepts and Relations in Neurally Inspired In Situ Concept-Based Computing

PubMed Central

van der Velde, Frank

2016-01-01

In situ concept-based computing is based on the notion that conceptual representations in the human brain are “in situ.” In this way, they are grounded in perception and action. Examples are neuronal assemblies, whose connection structures develop over time and are distributed over different brain areas. In situ concepts representations cannot be copied or duplicated because that will disrupt their connection structure, and thus the meaning of these concepts. Higher-level cognitive processes, as found in language and reasoning, can be performed with in situ concepts by embedding them in specialized neurally inspired “blackboards.” The interactions between the in situ concepts and the blackboards form the basis for in situ concept computing architectures. In these architectures, memory (concepts) and processing are interwoven, in contrast with the separation between memory and processing found in Von Neumann architectures. Because the further development of Von Neumann computing (more, faster, yet power limited) is questionable, in situ concept computing might be an alternative for concept-based computing. In situ concept computing will be illustrated with a recently developed BABI reasoning task. Neurorobotics can play an important role in the development of in situ concept computing because of the development of in situ concept representations derived in scenarios as needed for reasoning tasks. Neurorobotics would also benefit from power limited and in situ concept computing. PMID:27242504

Concepts and Relations in Neurally Inspired In Situ Concept-Based Computing.

PubMed

van der Velde, Frank

2016-01-01

In situ concept-based computing is based on the notion that conceptual representations in the human brain are "in situ." In this way, they are grounded in perception and action. Examples are neuronal assemblies, whose connection structures develop over time and are distributed over different brain areas. In situ concepts representations cannot be copied or duplicated because that will disrupt their connection structure, and thus the meaning of these concepts. Higher-level cognitive processes, as found in language and reasoning, can be performed with in situ concepts by embedding them in specialized neurally inspired "blackboards." The interactions between the in situ concepts and the blackboards form the basis for in situ concept computing architectures. In these architectures, memory (concepts) and processing are interwoven, in contrast with the separation between memory and processing found in Von Neumann architectures. Because the further development of Von Neumann computing (more, faster, yet power limited) is questionable, in situ concept computing might be an alternative for concept-based computing. In situ concept computing will be illustrated with a recently developed BABI reasoning task. Neurorobotics can play an important role in the development of in situ concept computing because of the development of in situ concept representations derived in scenarios as needed for reasoning tasks. Neurorobotics would also benefit from power limited and in situ concept computing.

Family Conflict and Children's Self-Concepts: A Comparison of Intact and Single-Parent Families.

ERIC Educational Resources Information Center

Raschke, Helen J.; Raschke, Vernon J.

1979-01-01

Using the Piers-Harris Children's Self-Concept Scale to measure self-concept, and self-reports for family structure and family conflict, no significant differences in self-concept scores of children from intact, single-parent, reconstituted, or other types of families were found. Self-concept scores were significantly lower for children reporting…

Study on utilization of advanced composites in fuselage structures of large transports

NASA Technical Reports Server (NTRS)

Johnson, R. W.; Thomson, L. W.; Wilson, R. D.

1985-01-01

The potential for utilizing advanced composites in fuselage structures of large transports was assessed. Six fuselage design concepts were selected and evaluated in terms of structural performance, weight, and manufacturing development and costs. Two concepts were selected that merit further consideration for composite fuselage application. These concepts are: (1) a full depth honeycomb design with no stringers, and (2) an I section stringer stiffened laminate skin design. Weight reductions due to applying composites to the fuselages of commercial and military transports were calculated. The benefits of applying composites to a fleet of military transports were determined. Significant technology issues pertinent to composite fuselage structures were identified and evaluated. Program plans for resolving the technology issues were developed.

A structurally adaptive space crane concept for assembling space systems on orbit

NASA Technical Reports Server (NTRS)

Dorsey, John T.; Sutter, Thomas R.; Wu, K. C.

1992-01-01

A space crane concept is presented which is based on erectable truss hardware to achieve high stiffness and low mass booms and articulating-truss joints which can be assembled on orbit. The hardware is characterized by linear load-deflection response and is structurally predictable. The crane can be reconfigured into different geometries to meet future assembly requirements. Articulating-truss joint concepts with significantly different geometries are analyzed and found to have similar static and dynamic performance, which indicates that criteria other than structural and kinematic performance can be used to select a joint. Passive damping and an open-loop preshaped command input technique greatly enhance the structural damping in the space crane and may preclude the need for an active vibrations suppression system.

Data structures and apparatuses for representing knowledge

DOEpatents

Hohimer, Ryan E; Thomson, Judi R; Harvey, William J; Paulson, Patrick R; Whiting, Mark A; Tratz, Stephen C; Chappell, Alan R; Butner, Robert S

2014-02-18

Data structures and apparatuses to represent knowledge are disclosed. The processes can comprise labeling elements in a knowledge signature according to concepts in an ontology and populating the elements with confidence values. The data structures can comprise knowledge signatures stored on computer-readable media. The knowledge signatures comprise a matrix structure having elements labeled according to concepts in an ontology, wherein the value of the element represents a confidence that the concept is present in an information space. The apparatus can comprise a knowledge representation unit having at least one ontology stored on a computer-readable medium, at least one data-receiving device, and a processor configured to generate knowledge signatures by comparing datasets obtained by the data-receiving devices to the ontologies.

Processes, data structures, and apparatuses for representing knowledge

DOEpatents

Hohimer, Ryan E [West Richland, WA; Thomson, Judi R [Guelph, CA; Harvey, William J [Richland, WA; Paulson, Patrick R [Pasco, WA; Whiting, Mark A [Richland, WA; Tratz, Stephen C [Richland, WA; Chappell, Alan R [Seattle, WA; Butner, R Scott [Richland, WA

2011-09-20

Processes, data structures, and apparatuses to represent knowledge are disclosed. The processes can comprise labeling elements in a knowledge signature according to concepts in an ontology and populating the elements with confidence values. The data structures can comprise knowledge signatures stored on computer-readable media. The knowledge signatures comprise a matrix structure having elements labeled according to concepts in an ontology, wherein the value of the element represents a confidence that the concept is present in an information space. The apparatus can comprise a knowledge representation unit having at least one ontology stored on a computer-readable medium, at least one data-receiving device, and a processor configured to generate knowledge signatures by comparing datasets obtained by the data-receiving devices to the ontologies.

Integration of nursing assessment concepts into the medical entities dictionary using the LOINC semantic structure as a terminology model.

PubMed

Cieslowski, B J; Wajngurt, D; Cimino, J J; Bakken, S

2001-01-01

Recent investigations have tested the applicability of various terminology models for the representing nursing concepts including those related to nursing diagnoses, nursing interventions, and standardized nursing assessments as a prerequisite for building a reference terminology that supports the nursing domain. We used the semantic structure of Clinical LOINC (Logical Observations, Identifiers, Names, and Codes) as a reference terminology model to support the integration of standardized assessment terms from two nursing terminologies into the Medical Entities Dictionary (MED), the concept-oriented, metadata dictionary at New York Presbyterian Hospital. Although the LOINC semantic structure was used previously to represent laboratory terms in the MED, selected hierarchies and semantic slots required revisions in order to incorporate the nursing assessment concepts. This project was an initial step in integrating nursing assessment concepts into the MED in a manner consistent with evolving standards for reference terminology models. Moreover, the revisions provide the foundation for adding other types of standardized assessments to the MED.

Integration of nursing assessment concepts into the medical entities dictionary using the LOINC semantic structure as a terminology model.

PubMed Central

Cieslowski, B. J.; Wajngurt, D.; Cimino, J. J.; Bakken, S.

2001-01-01

Recent investigations have tested the applicability of various terminology models for the representing nursing concepts including those related to nursing diagnoses, nursing interventions, and standardized nursing assessments as a prerequisite for building a reference terminology that supports the nursing domain. We used the semantic structure of Clinical LOINC (Logical Observations, Identifiers, Names, and Codes) as a reference terminology model to support the integration of standardized assessment terms from two nursing terminologies into the Medical Entities Dictionary (MED), the concept-oriented, metadata dictionary at New York Presbyterian Hospital. Although the LOINC semantic structure was used previously to represent laboratory terms in the MED, selected hierarchies and semantic slots required revisions in order to incorporate the nursing assessment concepts. This project was an initial step in integrating nursing assessment concepts into the MED in a manner consistent with evolving standards for reference terminology models. Moreover, the revisions provide the foundation for adding other types of standardized assessments to the MED. PMID:11825165

Space Spider - A concept for fabrication of large structures

NASA Technical Reports Server (NTRS)

Britton, W. R.; Johnston, J. D.

1978-01-01

The Space Spider concept for the automated fabrication of large space structures involves a specialized machine which roll-forms thin gauge material such as aluminum and develops continuous spiral structures with radial struts to sizes of 600-1,000 feet in diameter by 15 feet deep. This concept allows the machine and raw material to be integrated using the Orbiter capabilities, then boosting the rigid system to geosynchronous equatorial orbit (GEO) without high sensitivity to acceleration forces. As a teleoperator controlled device having repetitive operations, the fabrication process can be monitored and verified from a ground-based station without astronaut involvement in GEO. The resultant structure will be useful as an intermediate size platform or as a structural element to be used with other elements such as the space-fabricated beams or composite nested tubes.

Content Structure as a Design Strategy Variable in Concept Acquisition.

ERIC Educational Resources Information Center

Tennyson, Robert D.; Tennyson, Carol L.

Three methods of sequencing coordinate concepts (simultaneous, collective, and successive) were investigated with a Bayesian, computer-based, adaptive control system. The data analysis showed that when coordinate concepts are taught simultaneously (contextually similar concepts presented at the same time), student performance is superior to either…

Brain and Language.

ERIC Educational Resources Information Center

Damasio, Antonio R., Damasio, Hanna

1992-01-01

Discusses the advances made in understanding the brain structures responsible for language. Presents findings made using magnetic resonance imaging (MRI) and positron emission tomographic (PET) scans to study brain activity. These findings map the structures in the brain that manipulate concepts and those that turn concepts into words. (MCO)

Thermal design of composite materials high temperature attachments

NASA Technical Reports Server (NTRS)

1972-01-01

The thermal aspects of using filamentary composite materials as primary airframe structures on advanced atmospheric entry spacecraft such as the space shuttle vehicle were investigated to identify and evaluate potential design approaches for maintaining composite structures within allowable temperature limits at thermal protection system (TPS) attachments and/or penetrations. The investigation included: (1) definition of thermophysical data for composite material structures; (2) parametric characterization and identification of the influence of the aerodynamic heating and attachment design parameters on composite material temperatures; (3) conceptual design, evaluation, and detailed thermal analyses of temperature limiting design concepts; and (4) the development of experimental data for assessment of the thermal design methodologies and data used for evaluation of the temperature-limiting design concepts. Temperature suppression attachment concepts were examined for relative merit. The simple isolator was identified as the most weight-effective concept and was selected for detail design, thermal analysis, and testing. Tests were performed on TPS standoff attachments to boron/aluminum, boron/polyimide and graphite/epoxy composite structures.

Development of thermoplastic composite aircraft structures

NASA Technical Reports Server (NTRS)

Renieri, Michael P.; Burpo, Steven J.; Roundy, Lance M.; Todd, Stephanie A.; Kim, H. J.

1992-01-01

Efforts focused on the use of thermoplastic composite materials in the development of structural details associated with an advanced fighter fuselage section with applicability to transport design. In support of these designs, mechanics developments were conducted in two areas. First, a dissipative strain energy approach to material characterization and failure prediction, developed at the Naval Research Laboratory, was evaluated as a design/analysis tool. Second, a finite element formulation for thick composites was developed and incorporated into a lug analysis method which incorporates pin bending effects. Manufacturing concepts were developed for an upper fuel cell cover. A detailed trade study produced two promising concepts: fiber placement and single-step diaphragm forming. Based on the innovative design/manufacturing concepts for the fuselage section primary structure, elements were designed, fabricated, and structurally tested. These elements focused on key issues such as thick composite lugs and low cost forming of fastenerless, stiffener/moldine concepts. Manufacturing techniques included autoclave consolidation, single diaphragm consolidation (SDCC) and roll-forming.

A manned-machine space station construction concept

NASA Technical Reports Server (NTRS)

Mikulas, M. M., Jr.; Bush, H. G.; Wallsom, R. E.; Dorsey, J. T.; Rhodes, M. D.

1984-01-01

A design concept for the construction of a permanent manned space station is developed and discussed. The main considerations examined in developing the design concept are: (1) the support structure of the station be stiff enough to preclude the need for an elaborate on-orbit system to control structural response, (2) the station support structure and solar power system be compatible with existing technology, and (3) the station be capable of growing in a systematic modular fashion. The concept is developed around the assembly of truss platforms by pressure-suited astronauts operating in extravehicular activity (EVA), assisted by a machine (Assembly and Transport Vehicle, ATV) to position the astronauts at joint locations where they latch truss members in place. The ATV is a mobile platform that is attached to and moves on the station support structure using pegs attached to each truss joint. The operation of the ATV is described and a number of conceptual configurations for potential space stations are developed.

Structures of feeling and sociocultural formations: the significance of literature and experience to Raymond Williams's sociology of culture.

PubMed

Filmer, Paul

2003-06-01

Williams elaborates the concept of structures of feeling in different ways at important points in his writings. This gives it a particular methodological significance in relating the extraordinariness of imaginative literature to the ordinariness of cultural process. It is employed particularly to show the significance of literature for the articulation of alternatives to dominant world views, and thus to the politics of social change. Williams's different formulations of the concept are discussed in terms of their ways of relating reflexive experience to institutional structures and in relation to the genetic structuralism of Goldmann and Bourdieu's concepts of habitus and cultural field. Three types of criticisms are considered, which have in common the contention that the concept is unclear. Operationalized in analysing literature and its symbols, it can contribute towards clarification of the complexity of the processes of reflexive communication of experience which are at the root of social order and change.

Complex overlapping concepts: An effective auditing methodology for families of similarly structured BioPortal ontologies.

PubMed

Zheng, Ling; Chen, Yan; Elhanan, Gai; Perl, Yehoshua; Geller, James; Ochs, Christopher

2018-05-28

In previous research, we have demonstrated for a number of ontologies that structurally complex concepts (for different definitions of "complex") in an ontology are more likely to exhibit errors than other concepts. Thus, such complex concepts often become fertile ground for quality assurance (QA) in ontologies. They should be audited first. One example of complex concepts is given by "overlapping concepts" (to be defined below.) Historically, a different auditing methodology had to be developed for every single ontology. For better scalability and efficiency, it is desirable to identify family-wide QA methodologies. Each such methodology would be applicable to a whole family of similar ontologies. In past research, we had divided the 685 ontologies of BioPortal into families of structurally similar ontologies. We showed for four ontologies of the same large family in BioPortal that "overlapping concepts" are indeed statistically significantly more likely to exhibit errors. In order to make an authoritative statement concerning the success of "overlapping concepts" as a methodology for a whole family of similar ontologies (or of large subhierarchies of ontologies), it is necessary to show that "overlapping concepts" have a higher likelihood of errors for six out of six ontologies of the family. In this paper, we are demonstrating for two more ontologies that "overlapping concepts" can successfully predict groups of concepts with a higher error rate than concepts from a control group. The fifth ontology is the Neoplasm subhierarchy of the National Cancer Institute thesaurus (NCIt). The sixth ontology is the Infectious Disease subhierarchy of SNOMED CT. We demonstrate quality assurance results for both of them. Furthermore, in this paper we observe two novel, important, and useful phenomena during quality assurance of "overlapping concepts." First, an erroneous "overlapping concept" can help with discovering other erroneous "non-overlapping concepts" in its vicinity. Secondly, correcting erroneous "overlapping concepts" may turn them into "non-overlapping concepts." We demonstrate that this may reduce the complexity of parts of the ontology, which in turn makes the ontology more comprehensible, simplifying maintenance and use of the ontology. Copyright © 2018. Published by Elsevier Inc.

Arrow-wing supersonic cruise aircraft structural design concepts evaluation. Volume 4: Sections 15 through 21

NASA Technical Reports Server (NTRS)

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

1975-01-01

The analyses performed to provide structural mass estimates for the arrow wing supersonic cruise aircraft are presented. To realize the full potential for structural mass reduction, a spectrum of approaches for the wing and fuselage primary structure design were investigated. The objective was: (1) to assess the relative merits of various structural arrangements, concepts, and materials; (2) to select the structural approach best suited for the Mach 2.7 environment; and (3) to provide construction details and structural mass estimates based on in-depth structural design studies. Production costs, propulsion-airframe integration, and advanced technology assessment are included.

Evaluation of laminar flow control system concepts for subsonic commercial transport aircraft

NASA Technical Reports Server (NTRS)

1978-01-01

A two-year study conducted to establish a basis for industry decisions on the application of laminar flow control (LFC) to future commercial transports was presented. Areas of investigation included: (1) mission definition and baseline selection; (2) concepts evaluations; and (3) LFC transport configuration selection and component design. The development and evaluation of competing design concepts was conducted in the areas of aerodynamics, structures and materials, and systems. The results of supporting wind tunnel and laboratory testing on a full-scale LFC wing panel, suction surface opening concepts and structural samples were included. A final LFC transport was configured in incorporating the results of concept evaluation studies and potential performance improvements were assessed. Remaining problems together with recommendations for future research are discussed.

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.

Definition of a 5MW/61.5m wind turbine blade reference model.

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

Resor, Brian Ray

2013-04-01

A basic structural concept of the blade design that is associated with the frequently utilized %E2%80%9CNREL offshore 5-MW baseline wind turbine%E2%80%9D is needed for studies involving blade structural design and blade structural design tools. The blade structural design documented in this report represents a concept that meets basic design criteria set forth by IEC standards for the onshore turbine. The design documented in this report is not a fully vetted blade design which is ready for manufacture. The intent of the structural concept described by this report is to provide a good starting point for more detailed and targeted investigationsmore » such as blade design optimization, blade design tool verification, blade materials and structures investigations, and blade design standards evaluation. This report documents the information used to create the current model as well as the analyses used to verify that the blade structural performance meets reasonable blade design criteria.« less

Hybrid deployable support truss designs for LDR

NASA Technical Reports Server (NTRS)

Hedgepeth, J.

1988-01-01

Concepts for a 20-meter diameter Large Deployable Reflector (LDR) deployable truss backup structure, and analytical predictions of its structural characteristics are discussed. The concept shown is referred to as the SIXPAC; It is a combination of the PACTRUSS concept and a single-fold beam, which would make up the desired backup structure. One advantage of retaining the PACTRUSS concept is its packaging density and its capability for synchronous deployment. Various 2-meter hexagonal panel arrangements are possible for this Hybrid PACTRUSS structure depending on the panel-to-structure attachment strategies used. Static analyses of the SIXPAC using various assumptions for truss designs and panel masses of 10 kg sq meters were performed to predict the tip displacement of the structure when supported at the center. The tip displacement ranged from 0.20 to 0.44 mm without the panel mass, and from 0.9 to 3.9 mm with the panel mass (in a 1-g field). The data indicate that the structure can be adequately ground tested to validate its required performance in space, assuming the required performance in space is approximately 100 microns. The static displacement at the tip of the structure when subjected to an angular acceleration of 0.001 rad/sec squared were estimated to range from 0.8 to 7.5 microns, depending on the type of truss elements.

Erectable/deployable concepts for large space system technology

NASA Technical Reports Server (NTRS)

Agan, W. E.

1980-01-01

Erectable/deployable space structure concepts particularly relating to the development of a science and applications space platform are presented. Design and operating features for an automatic coupler clevis joint, a side latching detent joint, and a module-to-module auto lock coupler are given. An analysis of the packaging characteristics of stacked subassembly, single fold, hybrid, and double fold concepts is given for various platform structure configurations. Payload carrier systems and assembly techniques are also discussed.

The Development of a Technical Conceptual Structure for the Concepts Possessed by Selected Quality Control Specialists. Report of a Research Project.

ERIC Educational Resources Information Center

Nee, John G.

This project had as its specific objective the development and field testing of a procedure for identifying the structure of technical concepts possessed by a group of selected quality control specialists. The associative theory of verbal behavior served as the rationale by which conceptual structures depicted by graphical maps of technical…

Design and evaluation of active cooling systems for Mach 6 cruise vehicle wings

NASA Technical Reports Server (NTRS)

Mcconarty, W. A.; Anthony, F. M.

1971-01-01

Active cooling systems, which included transpiration, film, and convective cooling concepts, are examined. Coolants included hydrogen, helium, air, and water. Heat shields, radiation barriers, and thermal insulation are considered to reduce heat flow to the cooling systems. Wing sweep angles are varied from 0 deg to 75 deg and wing leading edge radii of 0.05 inch and 2.0 inches are examined. Structural temperatures are varied to allow comparison of aluminum alloy, titanium alloy, and superalloy structural materials. Cooled wing concepts are compared among themselves, and with the uncooled concept on the basis of structural weight, cooling system weight, and coolant weight.

A Rational Analysis of Rule-Based Concept Learning

ERIC Educational Resources Information Center

Goodman, Noah D.; Tenenbaum, Joshua B.; Feldman, Jacob; Griffiths, Thomas L.

2008-01-01

This article proposes a new model of human concept learning that provides a rational analysis of learning feature-based concepts. This model is built upon Bayesian inference for a grammatically structured hypothesis space--a concept language of logical rules. This article compares the model predictions to human generalization judgments in several…

Concept Mapping for Critical Thinking: Efficacy, Timing, & Type

ERIC Educational Resources Information Center

Harris, Charles M.; Zha, Shenghua

2017-01-01

Many college students are not progressing in the development of their critical thinking skills. Concept mapping is a technique for facilitating validation of one's critical thinking by graphically depicting the structure of complex concepts. Each of our three studies of concept mapping involved approximately 240 students enrolled in four sections…

Setting the Scope of Concept Inventories for Introductory Computing Subjects

ERIC Educational Resources Information Center

Goldman, Ken; Gross, Paul; Heeren, Cinda; Herman, Geoffrey L.; Kaczmarczyk, Lisa; Loui, Michael C.; Zilles, Craig

2010-01-01

A concept inventory is a standardized assessment tool intended to evaluate a student's understanding of the core concepts of a topic. In order to create a concept inventory it is necessary to accurately identify these core concepts. A Delphi process is a structured multi-step process that uses a group of experts to achieve a consensus opinion. We…

Measuring Social Studies Concept Attainment: Boys and Girls. Report from the Project on A Structure of Concept Attainment Abilities.

ERIC Educational Resources Information Center

Harris, Margaret L.; Tabachnick, B. Robert

This paper describes test development efforts for measuring achievement of selected concepts in social studies. It includes descriptive item and test statistics for the tests developed. Twelve items were developed for each of 30 concepts. Subject specialists categorized the concepts into three major areas: Geographic Region, Man and Society, and…

Universal first-order reliability concept applied to semistatic structures

NASA Technical Reports Server (NTRS)

Verderaime, V.

1994-01-01

A reliability design concept was developed for semistatic structures which combines the prevailing deterministic method with the first-order reliability method. The proposed method surmounts deterministic deficiencies in providing uniformly reliable structures and improved safety audits. It supports risk analyses and reliability selection criterion. The method provides a reliability design factor derived from the reliability criterion which is analogous to the current safety factor for sizing structures and verifying reliability response. The universal first-order reliability method should also be applicable for air and surface vehicles semistatic structures.

Universal first-order reliability concept applied to semistatic structures

NASA Astrophysics Data System (ADS)

Verderaime, V.

1994-07-01

A reliability design concept was developed for semistatic structures which combines the prevailing deterministic method with the first-order reliability method. The proposed method surmounts deterministic deficiencies in providing uniformly reliable structures and improved safety audits. It supports risk analyses and reliability selection criterion. The method provides a reliability design factor derived from the reliability criterion which is analogous to the current safety factor for sizing structures and verifying reliability response. The universal first-order reliability method should also be applicable for air and surface vehicles semistatic structures.

Constructing a self: the role of self-structure and self-certainty in social anxiety.

PubMed

Stopa, Lusia; Brown, Mike A; Luke, Michelle A; Hirsch, Colette R

2010-10-01

Current cognitive models stress the importance of negative self-perceptions in maintaining social anxiety, but focus predominantly on content rather than structure. Two studies examine the role of self-structure (self-organisation, self-complexity, and self-concept clarity) in social anxiety. In study one, self-organisation and self-concept clarity were correlated with social anxiety, and a step-wise multiple regression showed that after controlling for depression and self-esteem, which explained 35% of the variance in social anxiety scores, self-concept clarity uniquely predicted social anxiety and accounted for an additional 7% of the variance in social anxiety scores in an undergraduate sample (N=95) and the interaction between self-concept clarity and compartmentalisation (an aspect of evaluative self-organisation) at step 3 of the multiple regression accounted for a further 3% of the variance in social anxiety scores. In study two, high (n=26) socially anxious participants demonstrated less self-concept clarity than low socially anxious participants (n=26) on both self-report (used in study one) and on computerised measures of self-consistency and confidence in self-related judgments. The high socially anxious group had more compartmentalised self-organisation than the low anxious group, but there were no differences between the two groups on any of the other measures of self-organisation. Self-complexity did not contribute to social anxiety in either study, although this may have been due to the absence of a stressor. Overall, the results suggest that self-structure has a potentially important role in understanding social anxiety and that self-concept clarity and other aspects of self-structure such as compartmentalisation interact with each other and could be potential maintaining factors in social anxiety. Cognitive therapy for social phobia might influence self-structure, and understanding the role of structural variables in maintenance and treatment could eventually help to improve treatment outcome. Copyright 2010 Elsevier Ltd. All rights reserved.

Constructing a self: The role of self-structure and self-certainty in social anxiety

PubMed Central

Stopa, Lusia; Brown, Mike A.; Luke, Michelle A.; Hirsch, Colette R.

2010-01-01

Current cognitive models stress the importance of negative self-perceptions in maintaining social anxiety, but focus predominantly on content rather than structure. Two studies examine the role of self-structure (self-organisation, self-complexity, and self-concept clarity) in social anxiety. In study one, self-organisation and self-concept clarity were correlated with social anxiety, and a step-wise multiple regression showed that after controlling for depression and self-esteem, which explained 35% of the variance in social anxiety scores, self-concept clarity uniquely predicted social anxiety and accounted for an additional 7% of the variance in social anxiety scores in an undergraduate sample (N = 95) and the interaction between self-concept clarity and compartmentalisation (an aspect of evaluative self-organisation) at step 3 of the multiple regression accounted for a further 3% of the variance in social anxiety scores. In study two, high (n = 26) socially anxious participants demonstrated less self-concept clarity than low socially anxious participants (n = 26) on both self-report (used in study one) and on computerised measures of self-consistency and confidence in self-related judgments. The high socially anxious group had more compartmentalised self-organisation than the low anxious group, but there were no differences between the two groups on any of the other measures of self-organisation. Self-complexity did not contribute to social anxiety in either study, although this may have been due to the absence of a stressor. Overall, the results suggest that self-structure has a potentially important role in understanding social anxiety and that self-concept clarity and other aspects of self-structure such as compartmentalisation interact with each other and could be potential maintaining factors in social anxiety. Cognitive therapy for social phobia might influence self-structure, and understanding the role of structural variables in maintenance and treatment could eventually help to improve treatment outcome. PMID:20800751

Inflatable Space Structures Technology Development for Large Radar Antennas

NASA Technical Reports Server (NTRS)

Freeland, R. E.; Helms, Richard G.; Willis, Paul B.; Mikulas, M. M.; Stuckey, Wayne; Steckel, Gary; Watson, Judith

2004-01-01

There has been recent interest in inflatable space-structures technology for possible applications on U.S. Department of Defense (DOD) missions because of the technology's potential for high mechanical-packaging efficiency, variable stowed geometry, and deployment reliability. In recent years, the DOD sponsored Large Radar Antenna (LRA) Program applied this new technology to a baseline concept: a rigidizable/inflatable (RI) perimeter-truss structure supporting a mesh/net parabolic reflector antenna. The program addressed: (a) truss concept development, (b) regidizable materials concepts assessment, (c) mesh/net concept selection and integration, and (d) developed potential mechanical-system performance estimates. Critical and enabling technologies were validated, most notably the orbital radiation durable regidized materials and the high modulus, inflatable-deployable truss members. These results in conjunction with conclusions from previous mechanical-packaging studies by the U.S. Defense Advanced Research Projects Agency (DARPA) Special Program Office (SPO) were the impetus for the initiation of the DARPA/SPO Innovative Space-based Antenna Technology (ISAT) Program. The sponsor's baseline concept consisted of an inflatable-deployable truss structure for support of a large number of rigid, active radar panels. The program's goal was to determine the risk associated with the application of these new RI structures to the latest in radar technologies. The approach used to define the technology maturity level of critical structural elements was to: (a) develop truss concept baseline configurations (s), (b) assess specific inflatable-rigidizable materials technologies, and (c) estimate potential mechanical performance. The results of the structures portion of the program indicated there was high risk without the essential materials technology flight experiments, but only moderate risk if the appropriate on-orbit demonstrations were performed. This paper covers both programs (LRA and ISAT) in two sections, Parts 1 and 2 respectively. Please note that the terms strut, tube, and column are all used interchangeably and refer to the basic strut element of a truss. Also, the paper contains a mix of English and metric dimensional descriptions that reflect prevailing technical discipline conventions and common usage.

Novel In-Space Manufacturing Concepts for the Development of Large Space Telescopes

NASA Technical Reports Server (NTRS)

Mooney, James T.; Reardon, Patrick; Gregory Don; Manning, Andrew; Blackmon, Jim; Howsman, Tom; Williams, Philip; Brantley, Whitt; Rakoczy, John; Herren, Kenneth

2006-01-01

There is a continuous demand for larger, lighter, and higher quality telescopes. Over the past several decades, we have seen the evolution from launchable 2 meter-class telescopes (such as Hubble), to today s demand for deployable 6 meter-class telescopes (such as JWST), to tomorrow s need for up to 150 meter-class telescopes. As the apertures continue to grow, it will become much more difficult and expensive to launch assembled telescope structures. To address this issue, we are seeing the emergence of new novel structural concepts, such as inflatable structures and membrane optics. While these structural concepts do show promise, it is very difficult to achieve and maintain high surface figure quality. Another potential solution to develop large space telescopes is to move the fabrication facility into space and launch the raw materials. In this paper we present initial in-space manufacturing concepts to enable the development of large telescopes. This includes novel approaches for the fabrication of both the optical elements and the telescope support structure. We will also discuss potential optical designs for large space telescopes and describe their relation to the fabrication methods. These concepts are being developed to meet the demanding requirements of DARPA s LASSO (Large Aperture Space Surveillance Optic) program which currently requires a 150 meter optical aperture with a 17 degree field of view.

ACCESS 1: Approximation Concepts Code for Efficient Structural Synthesis program documentation and user's guide

NASA Technical Reports Server (NTRS)

Miura, H.; Schmit, L. A., Jr.

1976-01-01

The program documentation and user's guide for the ACCESS-1 computer program is presented. ACCESS-1 is a research oriented program which implements a collection of approximation concepts to achieve excellent efficiency in structural synthesis. The finite element method is used for structural analysis and general mathematical programming algorithms are applied in the design optimization procedure. Implementation of the computer program, preparation of input data and basic program structure are described, and three illustrative examples are given.

General aviation crash safety program at Langley Research Center

NASA Technical Reports Server (NTRS)

Thomson, R. G.

1976-01-01

The purpose of the crash safety program is to support development of the technology to define and demonstrate new structural concepts for improved crash safety and occupant survivability in general aviation aircraft. The program involves three basic areas of research: full-scale crash simulation testing, nonlinear structural analyses necessary to predict failure modes and collapse mechanisms of the vehicle, and evaluation of energy absorption concepts for specific component design. Both analytical and experimental methods are being used to develop expertise in these areas. Analyses include both simplified procedures for estimating energy absorption capabilities and more complex computer programs for analysis of general airframe response. Full-scale tests of typical structures as well as tests on structural components are being used to verify the analyses and to demonstrate improved design concepts.

A study of structural concepts for ultralightweight spacecraft

NASA Technical Reports Server (NTRS)

Miller, R. K.; Knapp, K.; Hedgepeth, J. M.

1984-01-01

Structural concepts for ultralightweight spacecraft were studied. Concepts for ultralightweight space structures were identified and the validity of heir potential application in advanced spacecraft was assessed. The following topics were investigated: (1) membrane wrinkling under pretensioning; (2) load-carrying capability of pressurized tubes; (3) equilibrium of a precompressed rim; (4) design of an inflated reflector spacecraft; (5) general instability of a rim; and (6) structural analysis of a pressurized isotensoid column. The design approaches for a paraboloidal reflector spacecraft included a spin-stiffened design, both inflated and truss central columns, and to include both deep truss and rim-stiffened geodesic designs. The spinning spacecraft analysis is included, and the two truss designs are covered. The performances of four different approaches to the structural design of a paraboloidal reflector spacecraft are compared. The spinning and inflated configurations result in very low total masses and some concerns about their performance due to unresolved questions about dynamic stability and lifetimes, respectively.

Study of advanced composite structural design concepts for an arrow wing supersonic cruise configuration

NASA Technical Reports Server (NTRS)

Turner, M. J.; Grande, D. L.

1978-01-01

Based on estimated graphite and boron fiber properties, allowable stresses and strains were established for advanced composite materials. Stiffened panel and conventional sandwich panel concepts were designed and analyzed, using graphite/polyimide and boron/polyimide materials. The conventional sandwich panel was elected as the structural concept for the modified wing structure. Upper and lower surface panels of the arrow wing structure were then redesigned, using high strength graphite/polyimide sandwich panels, retaining the titanium spars and ribs from the prior study. The ATLAS integrated analysis and design system was used for stress analysis and automated resizing of surface panels. Flutter analysis of the hybrid structure showed a significant decrease in flutter speed relative to the titanium wing design. The flutter speed was increased to that of the titanium design by selective increase in laminate thickness and by using graphite fibers with properties intermediate between high strength and high modulus values.

Perspective: Structural fluctuation of protein and Anfinsen's thermodynamic hypothesis

NASA Astrophysics Data System (ADS)

Hirata, Fumio; Sugita, Masatake; Yoshida, Masasuke; Akasaka, Kazuyuki

2018-01-01

The thermodynamics hypothesis, casually referred to as "Anfinsen's dogma," is described theoretically in terms of a concept of the structural fluctuation of protein or the first moment (average structure) and the second moment (variance and covariance) of the structural distribution. The new theoretical concept views the unfolding and refolding processes of protein as a shift of the structural distribution induced by a thermodynamic perturbation, with the variance-covariance matrix varying. Based on the theoretical concept, a method to characterize the mechanism of folding (or unfolding) is proposed. The transition state, if any, between two stable states is interpreted as a gap in the distribution, which is created due to an extensive reorganization of hydrogen bonds among back-bone atoms of protein and with water molecules in the course of conformational change. Further perspective to applying the theory to the computer-aided drug design, and to the material science, is briefly discussed.

Structurally Integrated Antenna Concepts for HALE UAVs

NASA Technical Reports Server (NTRS)

Cravey, Robin L.; Vedeler, Erik; Goins, Larry; Young, W. Robert; Lawrence, Roland W.

2006-01-01

This technical memorandum describes work done in support of the Multifunctional Structures and Materials Team under the Vehicle Systems Program's ITAS (Integrated Tailored Aero Structures) Project during FY 2005. The Electromagnetics and Sensors Branch (ESB) developed three ultra lightweight antenna concepts compatible with HALE UAVs (High Altitude Long Endurance Unmanned Aerial Vehicles). ESB also developed antenna elements that minimize the interaction between elements and the vehicle to minimize the impact of wing flexure on the EM (electromagnetic) performance of the integrated array. In addition, computer models were developed to perform phase correction for antenna arrays whose elements are moving relative to each other due to wing deformations expected in HALE vehicle concepts. Development of lightweight, conformal or structurally integrated antenna elements and compensating for the impact of a lightweight, flexible structure on a large antenna array are important steps in the realization of HALE UAVs for microwave applications such as passive remote sensing and communications.

Children's Conceptions of Air Pressure: Exploring the Nature of Conceptual Change.

ERIC Educational Resources Information Center

Tytler, Russell

1998-01-01

Constructs case studies of individuals to explore the way conceptions change over time, and the difficulties presented by the concept of atmospheric pressure. Evaluates different structural theories of conceptual change. Contains 62 references. (DDR)

Discovering More Chemical Concepts from 3D Chemical Information Searches of Crystal Structure Databases

ERIC Educational Resources Information Center

Rzepa, Henry S.

2016-01-01

Three new examples are presented illustrating three-dimensional chemical information searches of the Cambridge structure database (CSD) from which basic core concepts in organic and inorganic chemistry emerge. These include connecting the regiochemistry of aromatic electrophilic substitution with the geometrical properties of hydrogen bonding…

Fan Size and Foil Type in Recognition Memory.

ERIC Educational Resources Information Center

Walls, Richard T.; And Others

An experiment involving 20 graduate and undergraduate students (7 males and 13 females) at West Virginia University (Morgantown) assessed "fan network structures" of recognition memory. A fan in network memory structure occurs when several facts are connected into a single node (concept). The more links from that concept to various…

Concepts as Semantic Pointers: A Framework and Computational Model

ERIC Educational Resources Information Center

Blouw, Peter; Solodkin, Eugene; Thagard, Paul; Eliasmith, Chris

2016-01-01

The reconciliation of theories of concepts based on prototypes, exemplars, and theory-like structures is a longstanding problem in cognitive science. In response to this problem, researchers have recently tended to adopt either hybrid theories that combine various kinds of representational structure, or eliminative theories that replace concepts…

In defense of the Desiderata.

PubMed

Cimino, James J

2006-06-01

A 1998 paper that delineated desirable characteristics, or desiderata for controlled medical terminologies attempted to summarize emerging consensus regarding structural issues of such terminologies. Among the Desiderata was a call for terminologies to be "concept oriented." Since then, research has trended toward the extension of terminologies into ontologies. A paper by Smith, entitled "From Concepts to Clinical Reality: An Essay on the Benchmarking of Biomedical Terminologies" urges a realist approach that seeks terminologies composed of universals, rather than concepts. The current paper addresses issues raised by Smith and attempts to extend the Desiderata, not away from concepts, but towards recognition that concepts and universals must both be embraced and can coexist peaceably in controlled terminologies. To that end, additional Desiderata are defined that deal with the purpose, rather than the structure, of controlled medical terminologies.

Computer-Based Tutoring of Visual Concepts: From Novice to Experts.

ERIC Educational Resources Information Center

Sharples, Mike

1991-01-01

Description of ways in which computers might be used to teach visual concepts discusses hypermedia systems; describes computer-generated tutorials; explains the use of computers to create learning aids such as concept maps, feature spaces, and structural models; and gives examples of visual concept teaching in medical education. (10 references)…

"Structural Transformation" as a Threshold Concept in University Teaching

ERIC Educational Resources Information Center

Kinchin, Ian M.; Miller, Norma L.

2012-01-01

In an attempt to reveal potential threshold concepts in the field of higher education pedagogy, groups of university teachers (in the UK and in Panama) were encouraged to develop personal reflection upon their conceptions of teaching. This was initiated through concept mapping activities. It was hoped that this would help participants to address…

Concept Landscapes: Aggregating Concept Maps for Analysis

ERIC Educational Resources Information Center

Mühling, Andreas

2017-01-01

This article presents "concept landscapes"--a novel way of investigating the state and development of knowledge structures in groups of persons using concept maps. Instead of focusing on the assessment and evaluation of single maps, the data of many persons is aggregated and data mining approaches are used in analysis. New insights into…

Hybrid Wing-Body (HWB) Pressurized Fuselage Modeling, Analysis, and Design for Weight Reduction

NASA Technical Reports Server (NTRS)

Mukhopadhyay, Vivek

2012-01-01

This paper describes the interim progress for an in-house study that is directed toward innovative structural analysis and design of next-generation advanced aircraft concepts, such as the Hybrid Wing-Body (HWB) and the Advanced Mobility Concept-X flight vehicles, for structural weight reduction and associated performance enhancement. Unlike the conventional, skin-stringer-frame construction for a cylindrical fuselage, the box-type pressurized fuselage panels in the HWB undergo significant deformation of the outer aerodynamic surfaces, which must be minimized without significant structural weight penalty. Simple beam and orthotropic plate theory is first considered for sizing, analytical verification, and possible equivalent-plate analysis with appropriate simplification. By designing advanced composite stiffened-shell configurations, significant weight reduction may be possible compared with the sandwich and ribbed-shell structural concepts that have been studied previously. The study involves independent analysis of the advanced composite structural concepts that are presently being developed by The Boeing Company for pressurized HWB flight vehicles. High-fidelity parametric finite-element models of test coupons, panels, and multibay fuselage sections, were developed for conducting design studies and identifying critical areas of potential failure. Interim results are discussed to assess the overall weight/strength advantages.

Study of advanced composite structural design concepts for an arrow wing supersonic cruise configuration, task 3

NASA Technical Reports Server (NTRS)

1978-01-01

A structural design study was conducted to assess the relative merits of structural concepts using advanced composite materials for an advanced supersonic aircraft cruising at Mach 2.7. The configuration and structural arrangement developed during Task I and II of the study, was used as the baseline configuration. Allowable stresses and strains were established for boron and advanced graphite fibers based on projected fiber properties available in the next decade. Structural concepts were designed and analyzed using graphite polyimide and boron polyimide, applied to stiffened panels and conventional sandwich panels. The conventional sandwich panels were selected as the structural concept to be used on the wing structure. The upper and lower surface panels of the Task I arrow wing were redesigned using high-strength graphite polyimide sandwich panels over the titanium spars and ribs. The ATLAS computer system was used as the basis for stress analysis and resizing the surface panels using the loads from the Task II study, without adjustment for change in aeroelastic deformation. The flutter analysis indicated a decrease in the flutter speed compared to the baseline titanium wing design. The flutter analysis indicated a decrease in the flutter speed compared to the baseline titanium wing design. The flutter speed was increased to that of the titanium wing, with a weight penalty less than that of the metallic airplane.

Composite Payload Fairing Structural Architecture Assessment and Selection

NASA Technical Reports Server (NTRS)

Krivanek, Thomas M.; Yount, Bryan C.

2012-01-01

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 for specific Ares V components: the Payload Shroud, the Interstage, and the Core Stage Intertank. Team studies strived to address the structural challenges, risks and needs for each of these vehicle components. Leveraging off of this work, the subsequent Composites for Exploration (CoEx) effort is focused on providing a composite structural concept to support the Payload Fairing for SLS. This paper documents the evaluation and down selection of composite construction technologies and evolution to the SLS Payload Fairing. Development of the evaluation criteria (also referred to as Figures of Merit or FOMs), their relative importance, and association to vehicle requirements are presented. A summary of the evaluation results, and a recommendation of the composite concept to baseline in the Composites for Exploration (CoEx) project is presented. The recommendation for the SLS Fairing is a Honeycomb Sandwich architecture based primarily on affordability and performance with two promising alternatives, Hat stiffened and Fiber Reinforced Foam (FRF) identified for eventual program block upgrade.

Optimization of a Hot Structure Aeroshell and Nose Cap for Mars Atmospheric Entry

NASA Technical Reports Server (NTRS)

Langston, Sarah L.; Lang, Christapher G.; Samareh, Jamshid A.; Daryabeigi, Kamran

2016-01-01

The National Aeronautics and Space Administration (NASA) is preparing to send humans beyond Low Earth Orbit and eventually to the surface of Mars. As part of the Evolvable Mars Campaign, different vehicle configurations are being designed and considered for delivering large payloads to the surface of Mars. Weight and packing volume are driving factors in the vehicle design, and the thermal protection system (TPS) for planetary entry is a technology area which can offer potential weight and volume savings. The feasibility and potential benefits of a ceramic matrix composite hot structure concept for different vehicle configurations are explored in this paper, including the nose cap for a Hypersonic Inflatable Aerodynamic Decelerator (HIAD) and an aeroshell for a mid lift-to-drag (Mid L/D) concept. The TPS of a planetary entry vehicle is a critical component required to survive the severe aerodynamic heating environment during atmospheric en- try. The current state-of-the-art is an ablative material to protect the vehicle from the heat load. The ablator is bonded to an underlying structure, which carries the mechanical loads associated with entry. The alternative hot structure design utilizes an advanced carbon-carbon material system on the outer surface of the vehicle, which is exposed to the severe heating and acts as a load carrying structure. The preliminary design using the hot structure concept and the ablative concept is determined for the spherical nose cap of the HIAD entry vehicle and the aeroshell of the Mid L/D entry vehicle. The results of the study indicate that the use of hot structures for both vehicle concepts leads to a feasible design with potential weight and volume savings benefits over current state-of-the-art TPS technology that could enable future missions.

Effect of space structures against development of transport infrastructure in Banda Aceh by using the concept of transit oriented development

NASA Astrophysics Data System (ADS)

Noer, Fadhly; Matondang, A. Rahim; Sirojuzilam, Saleh, Sofyan M.

2017-11-01

Due to the shifting of city urban development causing the shift of city services center, so there is a change in space pattern and space structure in Banda Aceh, then resulting urban sprawl which can lead to congestion problem occurs on the arterial road in Banda Aceh, it can be seen from the increasing number of vehicles per year by 6%. Another issue occurs by urban sprawl is not well organized of settlement due to the uncontrolled use of space so that caused grouping or the differences in socioeconomic strata that can impact to the complexity of population mobility problem. From this background problem considered to be solved by a concept that is Transit Oriented Development (TOD), that is a concept of transportation development in co-operation with spatial. This research will get the model of transportation infrastructure development with TOD concept that can handle transportation problem in Banda Aceh, due to change of spatial structure, and to find whether TOD concept can use for the area that has a population in medium density range. The result that is obtained equation so the space structure is: Space Structure = 0.520 + 0.206X3 + 0.264X6 + 0.100X7 and Transportation Infrastructure Development = -1.457 + 0.652X1 + 0.388X5 + 0.235X6 + 0.222X7 + 0.327X8, So results obtained with path analysis method obtained variable influences, node ratio, network connectivity, travel frequency, travel destination, travel cost, and travel time, it has a lower value when direct effect with transportation infrastructure development, but if the indirect effect through the structure of space has a greater influence, can be seen from spatial structure path scheme - transportation infrastructure development.

Design of a radiator shade for testing in a simulated lunar environment

NASA Technical Reports Server (NTRS)

Huff, Jaimi; Remington, Randy; Tang, Toan

1992-01-01

The National Aeronautics and Space Administration (NASA) and The Universities Space Research Association (USRA) have chosen the parabolic/catenary concept from their sponsored Fall 1991 lunar radiation shade project for further testing and development. NASA asked the design team to build a shading device and support structure for testing in a vacuum chamber. Besides the support structure for the catenary shading device, the design team was asked to develop a system for varying the shade shape so that the device can be tested at different focal lengths. The design team developed concept variants and combined the concept variants to form overall designs. Using a decision matrix, an overall design was selected by the team from several overall design alternatives. Concept variants were developed for three primary functions. The three functions were structural support, shape adjustments, and end shielding. The shade adjustment function was divided into two sub-functions, arc length adjustment, and width adjustment.

Mechanization and Control Concepts for Biologically Inspired Micro Aerial Vehicles

NASA Technical Reports Server (NTRS)

Raney, David L.; Slominski, Eric C.

2003-01-01

It is possible that MAV designs of the future will exploit flapping flight in order to perform missions that require extreme agility, such as rapid flight beneath a forest canopy or within the confines of a building. Many of nature's most agile flyers generate flapping motions through resonant excitation of an aeroelastically tailored structure: muscle tissue is used to excite a vibratory mode of their flexible wing structure that creates propulsion and lift. A number of MAV concepts have been proposed that would operate in a similar fashion. This paper describes an ongoing research activity in which mechanization and control concepts with application to resonant flapping MAVs are being explored. Structural approaches, mechanical design, sensing and wingbeat control concepts inspired by hummingbirds, bats and insects are examined. Experimental results from a testbed capable of generating vibratory wingbeat patterns that approximately match those exhibited by hummingbirds in hover, cruise, and reverse flight are presented.

Mobile work station concept for assembly of large space structures (zero gravity simulation tests)

NASA Astrophysics Data System (ADS)

Heard, W. L., Jr.; Bush, H. G.; Wallsom, R. E.; Jensen, J. K.

1982-03-01

The concept presented is intended to enhance astronaut assembly of truss structure that is either too large or complex to fold for efficient Shuttle delivery to orbit. The potential of augmented astronaut assembly is illustrated by applying the result of the tests to a barebones assembly of a truss structure. If this structure were assembled from the same nestable struts that were used in the Mobile Work Station assembly tests, the spacecraft would be 55 meters in diameter and consist of about 500 struts. The struts could be packaged in less than 1/2% of the Shuttle cargo bay volume and would take up approximately 3% of the mass lift capability. They could be assembled in approximately four hours. This assembly concept for erectable structures is not only feasible, but could be used to significant economic advantage by permitting the superior packaging feature of erectable structures to be exploited and thereby reduce expensive Shuttle delivery flights.

Mobile work station concept for assembly of large space structures (zero gravity simulation tests)

NASA Technical Reports Server (NTRS)

Heard, W. L., Jr.; Bush, H. G.; Wallsom, R. E.; Jensen, J. K.

1982-01-01

The concept presented is intended to enhance astronaut assembly of truss structure that is either too large or complex to fold for efficient Shuttle delivery to orbit. The potential of augmented astronaut assembly is illustrated by applying the result of the tests to a barebones assembly of a truss structure. If this structure were assembled from the same nestable struts that were used in the Mobile Work Station assembly tests, the spacecraft would be 55 meters in diameter and consist of about 500 struts. The struts could be packaged in less than 1/2% of the Shuttle cargo bay volume and would take up approximately 3% of the mass lift capability. They could be assembled in approximately four hours. This assembly concept for erectable structures is not only feasible, but could be used to significant economic advantage by permitting the superior packaging feature of erectable structures to be exploited and thereby reduce expensive Shuttle delivery flights.

Importance of Kier-Hall topological indices in the QSAR of anticancer drug design.

PubMed

Nandi, Sisir; Bagchi, Manish C

2012-06-01

An important area of theoretical drug design research is quantitative structure activity relationship (QSAR) using structural invariants. The impetus for this research trend comes from various directions. Researchers in chemical documentation have searched for a set of invariants which will be more convenient than the adjacency matrix (or connection table) for the storage and comparison of chemical structures. Molecular structure can be looked upon as the representation of the relationship among its various constituents. The term molecular structure represents a set of nonequivalent and probably disjoint concepts. There is no reason to believe that when we discuss diverse topics (e.g. chemical synthesis, reaction rates, spectroscopic transitions, reaction mechanisms, and ab initio calculations) using the notion of molecular structure, the different meanings we attach to the single term molecular structure originate from the same fundamental concept. On the contrary, there is a theoretical and philosophical basis for the non-homogeneity of concepts covered by the term molecular structure. In the context of molecular science, the various concepts of molecular structure (e.g. classical valence bond representations, various chemical graph-theoretic representations, ball and spoke model of a molecule, representation of a molecule by minimum energy conformation, semi symbolic contour map of a molecule, or symbolic representation of chemical species by Hamiltonian operators) are model objects derived through different abstractions of the same chemical reality. In each instance, the equivalence class (concept or model of molecular structure) is generated by selecting certain aspects while ignoring some unique properties of those actual events. This explains the plurality of the concept of molecular structure and their autonomous nature, the word autonomous being used in the same sense that one concept is not logically derived from the other. At the most fundamental level, the structural model of an assembled entity (e.g. a molecule consisting of atoms) may be defined as the pattern of relationship among its parts as distinct from the values associated with them. Constitutional formulae of molecules are graphs where vertices represent the set of atoms and edges represent chemical bonds. The pattern of connectedness of atoms in a molecule is preserved by constitutional graphs. A graph (more correctly a non-directed graph) G = [V, E] consists of a finite non-empty set V of points together with a prescribed set E of unordered pairs of distinct points of V. Thus the mathematical characterization of structures represents structural invariants having successful applications in chemical documentation, characterization of molecular branching, enumeration of molecular constitutional associated with a particular empirical formula, calculation of quantum chemical parameters for the generation of quantitative structure-property-activity correlations. Kier developed a number of structural invariants which are now-a-days called as topological indices with wide range of practical applications for QSAR and drug design. The present paper is restricted to the review of Kier-Hall topological indices for QSAR and anticancer drug design for 2,5-bis(1-aziridinyl) 1,4-benzoquinone (BABQ), pyridopyrimidine, 4-anilinoquinazoline and 2-Phenylindoles compounds utilizing various statistical multivariate regression analyses.

Nursing intellectual capital theory: operationalization and empirical validation of concepts.

PubMed

Covell, Christine L; Sidani, Souraya

2013-08-01

To present the operationalization of concepts in the nursing intellectual capital theory and the results of a methodological study aimed at empirically validating the concepts. The nursing intellectual capital theory proposes that the stocks of nursing knowledge in an organization are embedded in two concepts, nursing human capital and nursing structural capital. The theory also proposes that two concepts in the work environment, nurse staffing and employer support for nursing continuing professional development, influence nursing human capital. A cross-sectional design. A systematic three-step process was used to operationalize the concepts of the theory. In 2008, data were collected for 147 inpatient units from administrative departments and unit managers in 6 Canadian hospitals. Exploratory factor analyses were conducted to determine if the indicator variables accurately reflect their respective concepts. The proposed indicator variables collectively measured the nurse staffing concept. Three indicators were retained to construct nursing human capital: clinical expertise and experience concept. The nursing structural capital and employer support for nursing continuing professional development concepts were not validated empirically. The nurse staffing and the nursing human capital: clinical expertise and experience concepts will be brought forward for further model testing. Refinement for some of the indicator variables of the concepts is indicated. Additional research is required with different sources of data to confirm the findings. © 2012 Blackwell Publishing Ltd.

Physical Concepts and Mathematical Symbols

NASA Astrophysics Data System (ADS)

Grelland, Hans Herlof

2007-12-01

According to traditional empiricist philosophy of science, concepts and meaning grow out of sense experience, and the mathematical structure of a physical theory is nothing but a formalisation of a given meaning-content. This view seems to work well in classical mechanics. But it breaks down in quantum physics, where we have a self-supported mathematical structure which resists any conceptual or pictorial interpretation in the traditional sense. Thus, traditional empiricism is flawed. Quantum physics teaches us that mathematics is a language in itself which extends beyond ordinary language. To understand the meaning of this extended language, we have to explore how new concepts and intuitions grow out of mathematics, not the other way around. The symbolic structure is prior to its meaning. This point of view is called linguistic empiricism, to stress that the connection with experience is still crucial. As cases, I compare the concept of stiffness in classical mechanics and the concept of electron density in quantum mechanics. The last case demonstrates that the wave function has a richer interpretation than the probabilistic one concerning measurement of position.

Discussion meeting on Gossamer spacecraft (ultralightweight spacecraft)

NASA Technical Reports Server (NTRS)

Brereton, R. G. (Editor)

1980-01-01

Concepts, technology, and application of ultralightweight structures in space are examined. Gossamer spacecraft represented a generic class of space vehicles or structures characterized by a low mass per unit area (approximately 50g/m2). Gossamer concepts include the solar sail, the space tether, and various two and three dimensional large lightweight structures that were deployed or assembled in space. The Gossamer Spacecraft had a high potential for use as a transportation device (solar sail), as a science instrument (reflecting or occulting antenna), or as a large structural component for an enclosure, manned platform, or other human habitats. Inflatable structures were one possible building element for large ultralightweight structures in space.

A Structural Model of Prospective Science Teachers' Nature of Science Views

ERIC Educational Resources Information Center

Mugaloglu, Ebru Z.; Bayram, Hale

2010-01-01

This study aims to establish a viable structural model of prospective science teachers' nature of science (NOS) views, which could be used as an analytical tool for understanding the complex relationships between prospective teachers' conceptions of NOS and factors possibly affecting their conceptions. In order to construct such a model, likely…

Bearing-Mounting Concept Accommodates Thermal Expansion

NASA Technical Reports Server (NTRS)

Nespodzany, Robert; Davis, Toren S.

1995-01-01

Pins or splines allow radial expansion without slippage. Design concept for mounting rotary bearing accommodates differential thermal expansion between bearing and any structure(s) to which bearing connected. Prevents buildup of thermal stresses by allowing thermal expansion to occur freely but accommodating expansion in such way not to introduce looseness. Pin-in-slot configuration also maintains concentricity.

Structuring Cooperative Learning for Motivation and Conceptual Change in the Concepts of Mixtures

ERIC Educational Resources Information Center

Belge Can, Hatice; Boz, Yezdan

2016-01-01

This study investigates the effect of structuring cooperative learning based on conceptual change approach on grade 9 students' understanding the concepts of mixtures and their motivation, compared with traditional instruction. Among six classes of a high school, two of them were randomly assigned to cooperative learning group where students were…

Cognitive Structures of University Students about Environmental Education, Climate Change and Consumption Concepts

ERIC Educational Resources Information Center

Keles, Özgül; Gilbertson, Kenneth L.; Uzun, Naim

2016-01-01

The purpose of this study was to determine cognitive structures and the retention of knowledge about environmental education, climate change and consumption concepts. The field of Environmental Education is increasingly including both climate change and consumption in the context of sustainability. Thus, this research is investigating the…

On the Concept "Microscope": Biology Student Teachers' Cognitive Structure

ERIC Educational Resources Information Center

Kurt, Hakan; Ekici, Gulay; Aktas, Murat; Aksu, Ozlem

2013-01-01

The purpose of the current study is to determine biology student teachers' cognitive structures on the concept of microscope. Qualitative research methodology has been applied in the study. The data were collected from biology student teachers. Free word association test and drawing-writing test were used to collect data. The data collected were…

Young Children's Psychological Selves: Convergence with Maternal Reports of Child Personality

ERIC Educational Resources Information Center

Brown, Geoffrey L.; Mangelsdorf, Sarah C.; Agathen, Jean M.; Ho, Moon-Ho

2008-01-01

The present research examined five-year-old children's psychological self-concepts. Non-linear factor analysis was used to model the latent structure of the children's self-view questionnaire (CSVQ; Eder, 1990), a measure of children's self-concepts. The coherence and reliability of the emerging factor structure indicated that young children are…

The "Schema" Concept: Bartlett Till Now. No. 21.

ERIC Educational Resources Information Center

Caramelli, Nicoletta

In 1932, F. C. Bartlett first used the concept of "schema" borrowing it from Head, to suggest a unitary structure whose elements interacted in a complex way. This structure, which aimed to insure the continuity of the cognizing organism, was at the same time the expression of the functional principle responsible for the mutual…

A study on design and development of enterprise-wide concepts for clinical documentation templates.

PubMed

Zhou, Li; Gurjar, Rupali; Regier, Rachel; Morgan, Stephen; Meyer, Theresa; Aroy, Teal; Goldman, Debora Scavone; Hongsermeier, Tonya; Middleton, Blackford

2008-11-06

Structured clinical documents are associated with many potential benefits. Underlying terminologies and structure of information are keys to their successful implementation and use. This paper presents a methodology for design and development of enterprise-wide concepts for clinical documentation templates for an ambulatory Electronic Medical Record (EMR) system.

Assessing the Structure of a Concept Map

ERIC Educational Resources Information Center

Giouvanakis, Thanasis; Samaras, Haido; Kehris, Evangelos; Mpakavos, Asterios

2013-01-01

This paper presents a framework for the evaluation of concept maps. We focus on supporting the student in dealing with ill-structured and complex problems. We argue that these problems require the application of "the modularity approach." In view of this, the paper describes ways of providing student support for the implementation of…

Psychological Separation, Attachment Security, Vocational Self-Concept Crystallization, and Career Indecision: A Structural Equation Analysis.

ERIC Educational Resources Information Center

Tokar, David M.; Withrow, Jason R.; Hall, Rosalie J.; Moradi, Bonnie

2003-01-01

Structural equation modeling was used to test theoretically based models in which psychological separation and attachment security variables were related to career indecision and those relations were mediated through vocational self-concept crystallization. Results indicated that some components of separation and attachment security did relate to…

Using Creative Problem Solving to Promote Students' Performance of Concept Mapping

ERIC Educational Resources Information Center

Tseng, Kuo-Hung; Chang, Chi-Cheng; Lou, Shi-Jer; Hsu, Pi-Shan

2013-01-01

The purpose of the study was to explore that using creative problem solving can promote students' performance of concept mapping (CMPING). Students were encouraged to use creative problem solving (CPS) in constructing nanometer knowledge structure, and then to promote the performance of CMPING. The knowledge structure was visualized through…

Language and Its Structure: Some Fundamental Linguistic Concepts.

ERIC Educational Resources Information Center

Langacker, Ronald W.

Intended for people with little or no training in linguistics, this book initially deals with such basic concepts as the definition of linguistics, the nature of language, and the linguistic variations within a society. The discussion then moves to a more detailed, non-historical analysis of language structure, focusing on lexical items,…

Refurbishment cost study of the thermal protection system of a space shuttle vehicle. Phase 2: Supplement

NASA Technical Reports Server (NTRS)

Haas, D. W.; Gerler, V. M.

1972-01-01

The labor costs and techniques associated with the maintenance of a bonded-on ablator thermal protection system (TPS) concept, suitable for Space Shuttle application are examined. The baseline approach to TPS attachment involves bonding reusable surface insulation (RSI) and/or ablators to the structural skin of the vehicle. The RSI and/or ablators in the form of either flat or contoured panels can be bonded to the skin of the primary structure directly or by way of an intermediate silicone foam rubber pad. The use of foam rubber pads permits the use of buckling skins and protruding heat rivets on the primary structure, minimizing structural weight and fabrication costs. In the case of the RSI, the foam rubber pad serves as a required strain isolator. For purpose of comparison, test data were obtained for an installation with and without the use of a strain isolator. The refurbishment aspects of a bonded-on RSI concept (without a strain isolator) were examined experimentally along with several externally removable panel concepts employing both ablator and RSI TPS. The various concepts are compared.

Development of moving spars for active aeroelastic structures

NASA Astrophysics Data System (ADS)

Amprikidis, Michael; Cooper, Jonathan E.

2003-08-01

This paper describes a research program investigating the development of "moving spars" to enable active aeroelastic control of aerospace structures. A number of different concepts have been considered as part of the EU funded Active Aeroelastic Aircraft Structures (3AS) project that enable the control of the bending and torsional stiffness of aircraft wings through changes in the internal aircraft structure. The aeroelastic behaviour, in particular static deflections, can be controlled as desired through changes in the position, orientation and stiffness of the spars. The concept described in this paper is based upon translational movement of the spars. This will result in changes in the torsional stiffness and shear centre position whilst leaving the bending stiffness unaffected. An analytical study of the aeroelastic behaviour demonstrates the benefits of using such an approach. An experimental investigation involving construction and bench testing of the concepts was undertaken to demonstrate its feasibility. Finally, a wind tunnel test of simple wing models constructed using these concepts was performed. The simulated and experimental results show that it is possible to control the wind twist in practice.

Large space structures and systems in the space station era: A bibliography with indexes (supplement 05)

NASA Technical Reports Server (NTRS)

1993-01-01

Bibliographies and abstracts are listed for 1363 reports, articles, and other documents introduced into the NASA scientific and technical information system between January 1, 1991 and July 31, 1992. Topics covered include technology development and mission design according to system, interactive analysis and design, structural and thermal analysis and design, structural concepts and control systems, electronics, advanced materials, assembly concepts, propulsion and solar power satellite systems.

Large space structures and systems in the space station era: A bibliography with indexes (supplement 05)

NASA Astrophysics Data System (ADS)

1993-03-01

Bibliographies and abstracts are listed for 1363 reports, articles, and other documents introduced into the NASA scientific and technical information system between January 1, 1991 and July 31, 1992. Topics covered include technology development and mission design according to system, interactive analysis and design, structural and thermal analysis and design, structural concepts and control systems, electronics, advanced materials, assembly concepts, propulsion and solar power satellite systems.

Redesign of solid rocket booster/external tank attachment ring for the space transportation system

NASA Technical Reports Server (NTRS)

Mccomb, Harvey G., Jr. (Compiler)

1987-01-01

An improved design concept is presented for the Space Shuttle solid rocket booster (SRB)/external tank (ET) attachment ring structural component. This component picks up three struts which attach the aft end of each SRB to the ET. The concept is a partial ring with carefully tapered ends to distribute fastener loads safely into the SRB. Extensive design studies and analyses were performed to arrive at the concept. Experiments on structural elements were performed to determine material strength and stiffness characteristics. Materials and fabrication studies were conducted to determine acceptable tolerances for the design concept. An overview is provided of the work along with conclusions and major recommendations.

Wide Field X-Ray Telescope Mission Concept Study Results

NASA Technical Reports Server (NTRS)

Hopkins, R. C.; Thomas, H. D.; Fabisinski, L. L.; Baysinger, M.; Hornsby, L. S.; Maples, C. D.; Purlee, T. E.; Capizzo, P. D.; Percy, T. K.

2014-01-01

The Wide Field X-Ray Telescope (WFXT) is an astrophysics mission concept for detecting and studying extra-galactic x-ray sources, including active galactic nuclei and clusters of galaxies, in an effort to further understand cosmic evolution and structure. This Technical Memorandum details the results of a mission concept study completed by the Advanced Concepts Office at NASA Marshall Space Flight Center in 2012. The design team analyzed the mission and instrument requirements, and designed a spacecraft that enables the WFXT mission while using high heritage components. Design work included selecting components and sizing subsystems for power, avionics, guidance, navigation and control, propulsion, structures, command and data handling, communications, and thermal control.

Approximation methods for combined thermal/structural design

NASA Technical Reports Server (NTRS)

Haftka, R. T.; Shore, C. P.

1979-01-01

Two approximation concepts for combined thermal/structural design are evaluated. The first concept is an approximate thermal analysis based on the first derivatives of structural temperatures with respect to design variables. Two commonly used first-order Taylor series expansions are examined. The direct and reciprocal expansions are special members of a general family of approximations, and for some conditions other members of that family of approximations are more accurate. Several examples are used to compare the accuracy of the different expansions. The second approximation concept is the use of critical time points for combined thermal and stress analyses of structures with transient loading conditions. Significant time savings are realized by identifying critical time points and performing the stress analysis for those points only. The design of an insulated panel which is exposed to transient heating conditions is discussed.

Finite element predictions of active buckling control of stiffened panels

NASA Astrophysics Data System (ADS)

Thompson, Danniella M.; Griffin, O. H., Jr.

1993-04-01

Materials systems and structures that can respond 'intelligently' to their environment are currently being proposed and investigated. A series of finite element analyses was performed to investigate the potential for active buckling control of two different stiffened panels by embedded shape memory alloy (SMA) rods. Changes in the predicted buckling load increased with the magnitude of the actuation level for a given structural concept. Increasing the number of actuators for a given concept yielded greater predicted increases in buckling load. Considerable control authority was generated with a small number of actuators, with greater authority demonstrated for those structural concepts where the activated SMA rods could develop greater forces and moments on the structure. Relatively simple and inexpensive analyses were performed with standard finite elements to determine such information, indicating the viability of these types of models for design purposes.

Evaluation of active cooling systems for a Mach 6 hypersonic transport airframe, part 2

NASA Technical Reports Server (NTRS)

Helenbrook, R. G.; Mcconarty, W. A.; Anthony, F. M.

1971-01-01

Transpiration and convective cooling concepts are examined for the fuselage and tail surface of a Mach 6 hypersonic transport aircraft. Hydrogen, helium, and water are considered as coolants. Heat shields and radiation barriers are examined to reduce heat flow to the cooled structures. The weight and insulation requirements for the cryogenic fuel tanks are examined so that realistic totals can be estimated for the complete fuselage and tail. Structural temperatures are varied to allow comparison of aluminum alloy, titanium alloy, and superalloy contruction materials. The results of the study are combined with results obtained on the wing structure, obtained in a previous study, to estimate weights for the complete airframe. The concepts are compared among themselves, and with the uncooled concept on the basis of structural weight, cooling system weight, and coolant weight.

Novel Composites for Wing and Fuselage Applications. Task 1; Novel Wing Design Concepts

NASA Technical Reports Server (NTRS)

Suarez, J. A.; Buttitta, C.; Flanagan, G.; DeSilva, T.; Egensteiner, W.; Bruno, J.; Mahon, J.; Rutkowski, C.; Collins, R.; Fidnarick, R.;

Computational Infrastructure for Engine Structural Performance Simulation

NASA Technical Reports Server (NTRS)

Chamis, Christos C.

1997-01-01

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

Concept for a 3D-printed soft rotary actuator driven by a shape-memory alloy

NASA Astrophysics Data System (ADS)

Yuan, Han; Chapelle, Frédéric; Fauroux, Jean-Christophe; Balandraud, Xavier

2018-05-01

In line with the recent development of soft actuators involving shape-memory alloys (SMAs) embedded in compliant structures, this paper proposes a concept for a rotary actuator driven by a SMA wire placed inside a 3D-printed helical structure. The concept consists of using the one-way memory effect of the SMA (activated by Joule heating) to create the rotation of a material point of the structure, while the inverse rotation is obtained during the return to ambient temperature thanks to the structure’s elasticity. The study was performed in three steps. First, a prototype was designed from a chain of design rules, and tested to validate the feasibility of the concept. Thermal and geometrical measurements were performed using infrared and visible-range stereo cameras. A clockwise rotation (250°) followed by an anti-clockwise rotation (‑200°) were obtained, enabling us to validate the concept despite the partial reversibility of the movement. Second, finite element simulations were performed to improve rotation reversibility. The high compliance of the mechanical system required a framework of large displacements for the calculations (in the strength of materials sense), due to the high structural flexibility. Finally, a second prototype was constructed and tested. Attention was paid to the rotation (fully reversible rotation of 150° reached) as well as to parasitic movements due to overall structural deformation. This study opens new prospects for the design and analysis of 3D-printed soft actuators activated by smart materials.

Analysis and Testing of a Metallic Repair Applicable to Pressurized Composite Aircraft Structure

NASA Technical Reports Server (NTRS)

Przekop, Adam; Jegley, Dawn C.; Rouse, Marshall; Lovejoy, Andrew E.

2014-01-01

Development of repair technology is vital to the long-term application of new structural concepts on aircraft structure. The design, analysis, and testing of a repair concept applicable to a stiffened composite panel based on the Pultruded Rod Stitched Efficient Unitized Structure was recently completed. The damage scenario considered was a mid-bay to mid-bay saw-cut with a severed stiffener, flange, and skin. A bolted metallic repair was selected so that it could be easily applied in the operational environment. The present work describes results obtained from tension and pressure panel tests conducted to validate both the repair concept and finite element analysis techniques used in the design effort. Simulation and experimental strain and displacement results show good correlation, indicating that the finite element modeling techniques applied in the effort are an appropriate compromise between required fidelity and computational effort. Static tests under tension and pressure loadings proved that the proposed repair concept is capable of sustaining load levels that are higher than those resulting from the current working stress allowables. Furthermore, the pressure repair panel was subjected to 55,000 pressure load cycles to verify that the design can withstand a life cycle representative for a transport category aircraft. These findings enable upward revision of the stress allowables that had been kept at an overly-conservative level due to concerns associated with repairability of the panels. This conclusion enables more weight efficient structural designs utilizing the composite concept under investigation.

Interactive Cohort Identification of Sleep Disorder Patients Using Natural Language Processing and i2b2.

PubMed

Chen, W; Kowatch, R; Lin, S; Splaingard, M; Huang, Y

2015-01-01

Nationwide Children's Hospital established an i2b2 (Informatics for Integrating Biology & the Bedside) application for sleep disorder cohort identification. Discrete data were gleaned from semistructured sleep study reports. The system showed to work more efficiently than the traditional manual chart review method, and it also enabled searching capabilities that were previously not possible. We report on the development and implementation of the sleep disorder i2b2 cohort identification system using natural language processing of semi-structured documents. We developed a natural language processing approach to automatically parse concepts and their values from semi-structured sleep study documents. Two parsers were developed: a regular expression parser for extracting numeric concepts and a NLP based tree parser for extracting textual concepts. Concepts were further organized into i2b2 ontologies based on document structures and in-domain knowledge. 26,550 concepts were extracted with 99% being textual concepts. 1.01 million facts were extracted from sleep study documents such as demographic information, sleep study lab results, medications, procedures, diagnoses, among others. The average accuracy of terminology parsing was over 83% when comparing against those by experts. The system is capable of capturing both standard and non-standard terminologies. The time for cohort identification has been reduced significantly from a few weeks to a few seconds. Natural language processing was shown to be powerful for quickly converting large amount of semi-structured or unstructured clinical data into discrete concepts, which in combination of intuitive domain specific ontologies, allows fast and effective interactive cohort identification through the i2b2 platform for research and clinical use.

Change in emotional self-concept following socio-cognitive training relates to structural plasticity of the prefrontal cortex.

PubMed

Lumma, Anna-Lena; Valk, Sofie L; Böckler, Anne; Vrtička, Pascal; Singer, Tania

2018-04-01

Self-referential processing is a key component of the emotional self-concept. Previous studies have shown that emotional self-referential processing is related to structure and function of cortical midline areas such as medial prefrontal cortex (mPFC), and that it can be altered on a behavioral level by specific mental training practices. However, it remains unknown how behavioral training-related change in emotional self-concept content relates to structural plasticity. To address this issue, we examined the relationship between training-induced change in participant's emotional self-concept measured through emotional word use in the Twenty Statement Test and change in cortical thickness in the context of a large-scale longitudinal mental training study called the ReSource Project . Based on prior behavioral findings showing increased emotional word use particularly after socio-cognitive training targeting perspective-taking capacities, this study extended these results by revealing that individual differences in the degree to which participants changed their emotional self-concept after training was positively related to cortical thickness change in right mPFC extending to dorsolateral PFC (dlPFC). Furthermore, increased self-related negative emotional word use after training was positively associated with cortical thickness change in left pars orbitalis and bilateral dlPFC. Our findings reveal training-related structural brain change in regions known to be involved in self-referential processing and cognitive control, and could indicate a relationship between restructuring of the emotional self-concept content as well as reappraisal of negative aspects and cortical thickness change. As such, our findings can guide the development of psychological interventions targeted to alter specific facets of the self-concept.

Interactive Cohort Identification of Sleep Disorder Patients Using Natural Language Processing and i2b2

PubMed Central

Chen, W.; Kowatch, R.; Lin, S.; Splaingard, M.

2015-01-01

Summary Nationwide Children’s Hospital established an i2b2 (Informatics for Integrating Biology & the Bedside) application for sleep disorder cohort identification. Discrete data were gleaned from semistructured sleep study reports. The system showed to work more efficiently than the traditional manual chart review method, and it also enabled searching capabilities that were previously not possible. Objective We report on the development and implementation of the sleep disorder i2b2 cohort identification system using natural language processing of semi-structured documents. Methods We developed a natural language processing approach to automatically parse concepts and their values from semi-structured sleep study documents. Two parsers were developed: a regular expression parser for extracting numeric concepts and a NLP based tree parser for extracting textual concepts. Concepts were further organized into i2b2 ontologies based on document structures and in-domain knowledge. Results 26,550 concepts were extracted with 99% being textual concepts. 1.01 million facts were extracted from sleep study documents such as demographic information, sleep study lab results, medications, procedures, diagnoses, among others. The average accuracy of terminology parsing was over 83% when comparing against those by experts. The system is capable of capturing both standard and non-standard terminologies. The time for cohort identification has been reduced significantly from a few weeks to a few seconds. Conclusion Natural language processing was shown to be powerful for quickly converting large amount of semi-structured or unstructured clinical data into discrete concepts, which in combination of intuitive domain specific ontologies, allows fast and effective interactive cohort identification through the i2b2 platform for research and clinical use. PMID:26171080

Feasibility of a 30-meter space based laser transmitter

NASA Technical Reports Server (NTRS)

Berggren, R. R.; Lenertz, G. E.

1975-01-01

A study was made of the application of large expandable mirror structures in future space missions to establish the feasibility and define the potential of high power laser systems for such applications as propulsion and power transmission. Application of these concepts requires a 30-meter diameter, diffraction limited mirror for transmission of the laser energy. Three concepts for the transmitter are presented. These concepts include consideration of continuous as well as segmented mirror surfaces and the major stow-deployment categories of inflatable, variable geometry and assembled-in-space structures. The mirror surface for each concept would be actively monitored and controlled to maintain diffraction limited performance at 10.6 microns during operation. The proposed mirror configurations are based on existing aerospace state-of-the-art technology. The assembled-in-space concept appears to be the most feasible, at this time.

Integrated Requirements Analysis and Technology Roadmaps

NASA Technical Reports Server (NTRS)

1997-01-01

In fiscal year 1997, Strategic Insight performed analytical studies for NASA's Highly Reusable Space Transportation (HRST) program, creating program documents which illuminated technical requirements and critical research opportunities. Studies were performed to structure and confirm HRST's evolving technical requirements, building on Marshall's Phase 1 work, which defined HRST system concepts, analytical tools and high-level issues for assessment in Phase 2. Specifically, Strategic Insight: (1) Performed a requirements analysis to update HRST: An Advanced Concepts Study, Study Guidelines, Version 2.0 of January 22, 1996; only minor changes were recommended for the given parameters of interest to concept designers; (2) Conducted mini-workshops during HRST Working Group meetings on April 14-15, 1997 and July 22-24, 1997; and (3) Created structures for technology road maps of candidate HRST concepts, both subsystem and end-to-end concepts, emerging from the 13 cooperative agreement projects.

The application of thermally induced multistable composites to morphing aircraft structures

NASA Astrophysics Data System (ADS)

Mattioni, Filippo; Weaver, Paul M.; Potter, Kevin D.; Friswell, Michael I.

2008-03-01

One approach to morphing aircraft is to use bistable or multistable structures that have two or more stable equilibrium configurations to define a discrete set of shapes for the morphing structure. Moving between these stable states may be achieved using an actuation system or by aerodynamic loads. This paper considers three concepts for morphing aircraft based on multistable structures, namely a variable sweep wing, bistable blended winglets and a variable camber trailing edge. The philosophy behind these concepts is outlined, and simulated and experimental results are given.

Dynamic and structural control utilizing smart materials and structures

NASA Technical Reports Server (NTRS)

Rogers, C. A.; Robertshaw, H. H.

1989-01-01

An account is given of several novel 'smart material' structural control concepts that are currently under development. The thrust of these investigations is the evolution of intelligent materials and structures superceding the recently defined variable-geometry trusses and shape memory alloy-reinforced composites; the substances envisioned will be able to autonomously evaluate emergent environmental conditions and adapt to them, and even change their operational objectives. While until now the primary objective of the developmental efforts presently discussed has been materials that mimic biological functions, entirely novel concepts may be formulated in due course.

Self-organized minimum-energy structures for dielectric elastomer actuators

NASA Astrophysics Data System (ADS)

Kofod, G.; Paajanen, M.; Bauer, S.

2006-11-01

When a stretched elastomer is laminated to a flat plastic frame, a complex shape is formed, which is termed a minimum-energy structure. It is shown how self-organized structures can be applied in the development of actuators with complex, out-of-plane actuationmodes. This unusual concept is then demonstrated in the case of dielectric elastomer actuators. Among advantages of this approach are the simplicity in manufacturing, the potential complexity and sophistication of the manufactured structures, and the general benefits of the concept when applied to other electro-mechanically active materials.

Textile technology development

NASA Technical Reports Server (NTRS)

Shah, Bharat M.

1995-01-01

The objectives of this report were to evaluate and select resin systems for Resin Transfer Molding (RTM) and Powder Towpreg Material, to develop and evaluate advanced textile processes by comparing 2-D and 3-D braiding for fuselage frame applications and develop window belt and side panel structural design concepts, to evaluate textile material properties, and to develop low cost manufacturing and tooling processes for the automated manufacturing of fuselage primary structures. This research was in support of the NASA and Langley Research Center (LaRc) Advanced Composite Structural Concepts and Materials Technologies for Primary Aircraft Structures program.

Structural load control during construction

NASA Technical Reports Server (NTRS)

Mikulas, Martin M., Jr.

1991-01-01

In the absence of gravitational pull, the major design considerations for large space structures are stiffness for controllability, and transient dynamic loadings (as opposed to the traditional static load associated with earth-based structures). Because of the absence of gravitational loading, space structures can be designed to be significantly lighter than their counterparts on Earth. For example, the Space Shuttle manipulator arm is capable of moving and positioning a 60,000 lb payload, yet weighs less than 1,000 lbs. A recent design for the Space Station which had a total weight of about 500,000 lbs. used a primary loadcarrying keel beam which weighed less than 10,000 lbs. For many large space structures designs it is quite common for the load-carrying structure to have a mass fraction on the order of one or two percent of the total spacecraft mass. This significant weight reduction for large space structures is commonly accompanied by very low natural frequencies. These low frequencies cause an unprecedented level of operational complexity for mission applications which require a high level of positioning and control accuracy. This control problem is currently the subject of considerable research directed towards reducing the flexibility problem. In addition, however, the small mass fraction typically results in structures which are quite unforgiving to inadvertent high loadings. In other words, the structures are 'fragile.' In order to deal with the fragility issue CSC developed a load-limiting concept for space truss structures. This concept is aimed at limiting the levels of load which can occur in a large space structure during the construction process as well as during subsequent operations. Currently, the approach for dealing with large loadings is to make the structure larger. The impact this has on construction is significant. The larger structures are more difficult to package in the launch vehicle, and in fact in some instances the concept must be changed from a deployable truss to an erectable truss to permit packaging. The new load-limiting concept is aimed at permitting the use in large space structures of smaller trusses with a high level of strength robustness, in order to simplify the construction process. To date several analyses conducted on the concept have demonstrated its feasibility, and an experiment is currently being designed to demonstrate its operation.

Infrastructure Retrofit Design via Composite Mechanics

NASA Technical Reports Server (NTRS)

Chamis, Christos, C.; Gotsis,Pascal K.

1998-01-01

Select applications are described to illustrate the concept for retrofitting reinforced concrete infrastructure with fiber reinforced plastic laminates. The concept is first illustrated by using an axially loaded reinforced concrete column. A reinforced concrete arch and a dome are then used to illustrate the versatility of the concept. Advanced methods such as finite element structural analysis and progressive structural fracture are then used to evaluate the retrofitting laminate adequacy. Results obtains show that retrofits can be designed to double and even triple the as-designed load of the select reinforced concrete infrastructures.

Production process stability - core assumption of INDUSTRY 4.0 concept

NASA Astrophysics Data System (ADS)

Chromjakova, F.; Bobak, R.; Hrusecka, D.

2017-06-01

Today’s industrial enterprises are confronted by implementation of INDUSTRY 4.0 concept with basic problem - stabilised manufacturing and supporting processes. Through this phenomenon of stabilisation, they will achieve positive digital management of both processes and continuously throughput. There is required structural stability of horizontal (business) and vertical (digitized) manufacturing processes, supported through digitalised technologies of INDUSTRY 4.0 concept. Results presented in this paper based on the research results and survey realised in more industrial companies. Following will described basic model for structural process stabilisation in manufacturing environment.

Technology for large space systems: A bibliography with indexes (supplement 11)

NASA Technical Reports Server (NTRS)

1985-01-01

This bibliography contains 539 abstracts of reports, articles and other documents introduced into the NASA scientific and technical information system between January 1, 1984 and December 31, 1984. Abstracts are arranged in the following categories: systems; analysis and design techniques; structural concepts; structural and thermal analysis; structural dynamics and control; electronics; advanced materials; assembly concepts; propulsion; and miscellaneous. Subject, personal author, corporate source, contract number, report number, and accession number indexes are listed.

Near Identifiability of Dynamical Systems

NASA Technical Reports Server (NTRS)

Hadaegh, F. Y.; Bekey, G. A.

1987-01-01

Concepts regarding approximate mathematical models treated rigorously. Paper presents new results in analysis of structural identifiability, equivalence, and near equivalence between mathematical models and physical processes they represent. Helps establish rigorous mathematical basis for concepts related to structural identifiability and equivalence revealing fundamental requirements, tacit assumptions, and sources of error. "Structural identifiability," as used by workers in this field, loosely translates as meaning ability to specify unique mathematical model and set of model parameters that accurately predict behavior of corresponding physical system.

A Longitudinal Study of Junior High School Students' Conceptions of the Structure of Materials

ERIC Educational Resources Information Center

Margel, Hannah; Eylon, Bat-Sheva; Scherz, Zahava

2008-01-01

This longitudinal study investigated the progression in junior high school (JHS) students' conceptions of the structure of matter while studying a new instructional approach dealing with "Materials." In particular, we studied the progression of students' learning along two dimensions: (a) the conceptual model; and (b) the context of application.…

Conceptual Representations of Flu and Microbial Illness Held by Students, Teachers, and Medical Professionals

ERIC Educational Resources Information Center

Jones, M. Gail; Rua, Melissa J.

2008-01-01

This study describes 5th, 8th, and 11th-grade students', teachers', and medical professionals' conceptions of flu and microbial illness. Participants constructed a concept map on "flu" and participated in a semi-structured interview. The results showed that these groups of students, teachers and medical professionals held and structured their…

Self-Constructs and Anxiety Across Cultures. Research Report. ETS RR-09-12

ERIC Educational Resources Information Center

Lee, Jihyun

2009-01-01

This study examined the factorial structure of three related constructs, math self-concept, math self-efficacy, and math anxiety, across 41 countries. One factorial structure was achieved at both between- and within-country levels. Within-country variations of the self-constructs were also noted in relation to math performance: Self-concept showed…

Cognitive Flexibility and Undergraduate Physiology Students: Increasing Advanced Knowledge Acquisition within an Ill-Structured Domain

ERIC Educational Resources Information Center

Rhodes, Ashley E.; Rozell, Timothy G.

2017-01-01

Cognitive flexibility is defined as the ability to assimilate previously learned information and concepts to generate novel solutions to new problems. This skill is crucial for success within ill-structured domains such as biology, physiology, and medicine, where many concepts are simultaneously required for understanding a complex problem, yet…

Physical Self-Concept in Adolescence: Generalizability of a Multidimensional, Hierarchical Model Across Gender and Grade

ERIC Educational Resources Information Center

Hagger, Martin S.; Biddle, Stuart J. H.; John Wang, C. K.

2005-01-01

This study tests the generalizability of the factor pattern, structural parameters, and latent mean structure of a multidimensional, hierarchical model of physical self-concept in adolescents across gender and grade. A children's version of the Physical Self-Perception Profile (C-PSPP) was administered to seventh-, eighth- and ninth-grade high…

Development of deployable structures for large space platforms. Volume 2: Design development

NASA Technical Reports Server (NTRS)

Greenberg, H. S.

1983-01-01

Design evolution, test article design, test article mass properties, and structural analysis of deployable platform systems are discussed. Orbit transfer vehicle (OTV) hangar development, OTV hangar concept selection, and manned module development are discussed. Deployable platform systems requirements, material data base, technology development needs, concept selection and deployable volume enclosures are also discussed.

Learning in Structured Connectionist Networks

DTIC Science & Technology

1988-04-01

the structure is too rigid and learning too difficult for cognitive modeling. Two algorithms for learning simple, feature-based concept descriptions...and learning too difficult for cognitive model- ing. Two algorithms for learning simple, feature-based concept descriptions were also implemented. The...Term Goals Recent progress in connectionist research has been encouraging; networks have success- fully modeled human performance for various cognitive

Using Structural Equation Modeling to Validate Online Game Players' Motivations Relative to Self-Concept and Life Adaptation

ERIC Educational Resources Information Center

Yang, Shu Ching; Huang, Chiao Ling

2013-01-01

This study aimed to validate a systematic instrument to measure online players' motivations for playing online games (MPOG) and examine how the interplay of differential motivations impacts young gamers' self-concept and life adaptation. Confirmatory factor analysis determined that a hierarchical model with a two-factor structure of…

Aggregating Concept Map Data to Investigate the Knowledge of Beginning CS Students

ERIC Educational Resources Information Center

Mühling, Andreas

2016-01-01

Concept maps have a long history in educational settings as a tool for teaching, learning, and assessing. As an assessment tool, they are predominantly used to extract the structural configuration of learners' knowledge. This article presents an investigation of the knowledge structures of a large group of beginning CS students. The investigation…

Genetic Epistemology and the Structure of Belief Systems: An Introduction to Piaget for Political Scientists.

ERIC Educational Resources Information Center

Ward, Dana

Suggesting that the concept of structure employed by political scientists in the analysis of belief systems is inadequate and misleading, the paper discusses Jean Piaget's concept of egocentrism as a theoretical alternative to belief systems analysis. The purpose of the paper is to provide political scientists with a short but comprehensive…

A Structural Model Related to the Understanding of the Concept of Function: Definition and Problem Solving

ERIC Educational Resources Information Center

Panaoura, Areti; Michael-Chrysanthou, Paraskevi; Gagatsis, Athanasios; Elia, Iliada; Philippou, Andreas

2017-01-01

This article focuses on exploring students' understanding of the concept of function concerning three main aspects: secondary students' ability to (1) define the concept of function and present examples of functions, (2) solve tasks which asked them to recognize and interpret the concept of function presented in different forms of representation,…

Concept "Medical Museum" as a Sociocultural Phenomenon

ERIC Educational Resources Information Center

Chizh, Nina V.; Slyshkin, Gennady G.; Zheltukhina, Marina R.; Privalova, Irina V.; Kravchenko, Olga A.

2016-01-01

The article examines the concept "medical museum" as a sociocultural phenomenon. The register of medical museums in Russia makes the material of research. The complex methods of analysis of the concept "medical museum" are used. The philosophical, historical, cultural, structural, communicative and semantic analysis is carried…

Toward a Post-Modern Agenda in Instructional Technology.

ERIC Educational Resources Information Center

Solomon, David L.

2000-01-01

Discusses the concept of post-modernism and relates it to the field of instructional technology. Topics include structuralism; semiotics; poststructuralism; deconstruction; knowledge and power; critical theory; self-concept; post-modern assumptions; and potential contributions of post-modern concepts in instructional technology. (Contains 80…

Brain Research and Learning.

ERIC Educational Resources Information Center

Claycomb, Mary

Current research on brain activity has many implications for educators. The triune brain concept and the left and right hemisphere concepts are among the many complex theories evolving from experimentation and observation. The triune brain concept suggests that the human forebrain has expanded while retaining three structurally unique formations…

Toward Semantic Interoperability in Home Health Care: Formally Representing OASIS Items for Integration into a Concept-oriented Terminology

PubMed Central

Choi, Jeungok; Jenkins, Melinda L.; Cimino, James J.; White, Thomas M.; Bakken, Suzanne

2005-01-01

Objective: The authors aimed to (1) formally represent OASIS-B1 concepts using the Logical Observation Identifiers, Names, and Codes (LOINC) semantic structure; (2) demonstrate integration of OASIS-B1 concepts into a concept-oriented terminology, the Medical Entities Dictionary (MED); (3) examine potential hierarchical structures within LOINC among OASIS-B1 and other nursing terms; and (4) illustrate a Web-based implementation for OASIS-B1 data entry using Dialogix, a software tool with a set of functions that supports complex data entry. Design and Measurements: Two hundred nine OASIS-B1 items were dissected into the six elements of the LOINC semantic structure and then integrated into the MED hierarchy. Each OASIS-B1 term was matched to LOINC-coded nursing terms, Home Health Care Classification, the Omaha System, and the Sign and Symptom Check-List for Persons with HIV, and the extent of the match was judged based on a scale of 0 (no match) to 4 (exact match). OASIS-B1 terms were implemented as a Web-based survey using Dialogix. Results: Of 209 terms, 204 were successfully dissected into the elements of the LOINC semantics structure and integrated into the MED with minor revisions of MED semantics. One hundred fifty-one OASIS-B1 terms were mapped to one or more of the LOINC-coded nursing terms. Conclusion: The LOINC semantic structure offers a standard way to add home health care data to a comprehensive patient record to facilitate data sharing for monitoring outcomes across sites and to further terminology management, decision support, and accurate information retrieval for evidence-based practice. The cross-mapping results support the possibility of a hierarchical structure of the OASIS-B1 concepts within nursing terminologies in the LOINC database. PMID:15802480

Toward semantic interoperability in home health care: formally representing OASIS items for integration into a concept-oriented terminology.

PubMed

Choi, Jeungok; Jenkins, Melinda L; Cimino, James J; White, Thomas M; Bakken, Suzanne

2005-01-01

The authors aimed to (1) formally represent OASIS-B1 concepts using the Logical Observation Identifiers, Names, and Codes (LOINC) semantic structure; (2) demonstrate integration of OASIS-B1 concepts into a concept-oriented terminology, the Medical Entities Dictionary (MED); (3) examine potential hierarchical structures within LOINC among OASIS-B1 and other nursing terms; and (4) illustrate a Web-based implementation for OASIS-B1 data entry using Dialogix, a software tool with a set of functions that supports complex data entry. Two hundred nine OASIS-B1 items were dissected into the six elements of the LOINC semantic structure and then integrated into the MED hierarchy. Each OASIS-B1 term was matched to LOINC-coded nursing terms, Home Health Care Classification, the Omaha System, and the Sign and Symptom Check-List for Persons with HIV, and the extent of the match was judged based on a scale of 0 (no match) to 4 (exact match). OASIS-B1 terms were implemented as a Web-based survey using Dialogix. Of 209 terms, 204 were successfully dissected into the elements of the LOINC semantics structure and integrated into the MED with minor revisions of MED semantics. One hundred fifty-one OASIS-B1 terms were mapped to one or more of the LOINC-coded nursing terms. The LOINC semantic structure offers a standard way to add home health care data to a comprehensive patient record to facilitate data sharing for monitoring outcomes across sites and to further terminology management, decision support, and accurate information retrieval for evidence-based practice. The cross-mapping results support the possibility of a hierarchical structure of the OASIS-B1 concepts within nursing terminologies in the LOINC database.

NeuroNames: an ontology for the BrainInfo portal to neuroscience on the web.

PubMed

Bowden, Douglas M; Song, Evan; Kosheleva, Julia; Dubach, Mark F

2012-01-01

BrainInfo ( http://braininfo.org ) is a growing portal to neuroscientific information on the Web. It is indexed by NeuroNames, an ontology designed to compensate for ambiguities in neuroanatomical nomenclature. The 20-year old ontology continues to evolve toward the ideal of recognizing all names of neuroanatomical entities and accommodating all structural concepts about which neuroscientists communicate, including multiple concepts of entities for which neuroanatomists have yet to determine the best or 'true' conceptualization. To make the definitions of structural concepts unambiguous and terminologically consistent we created a 'default vocabulary' of unique structure names selected from existing terminology. We selected standard names by criteria designed to maximize practicality for use in verbal communication as well as computerized knowledge management. The ontology of NeuroNames accommodates synonyms and homonyms of the standard terms in many languages. It defines complex structures as models composed of primary structures, which are defined in unambiguous operational terms. NeuroNames currently relates more than 16,000 names in eight languages to some 2,500 neuroanatomical concepts. The ontology is maintained in a relational database with three core tables: Names, Concepts and Models. BrainInfo uses NeuroNames to index information by structure, to interpret users' queries and to clarify terminology on remote web pages. NeuroNames is a resource vocabulary of the NLM's Unified Medical Language System (UMLS, 2011) and the basis for the brain regions component of NIFSTD (NeuroLex, 2011). The current version has been downloaded to hundreds of laboratories for indexing data and linking to BrainInfo, which attracts some 400 visitors/day, downloading 2,000 pages/day.

An assessment of high school students' conceptual structures of heat and temperature through concept maps

NASA Astrophysics Data System (ADS)

Aykutlu, Isil; Bezen, Sevim; Bayrak, Celal

2017-02-01

This study is a qualitative one conducted in order to determine 9th, 10th, and 11th grade high school students' conceptual structures of heat and temperature through concept maps. The study was realized with the participation of a total of 80 students. As data gathering tool, a concept map developed by the researchers, which includes such items as heat, temperature, and matter, was used. Students were asked to form a concept map by using the concepts in the form and the concepts they thought were related with these. Data obtained from the research was analyzed via content analysis. As a result of the study, it was determined that students have misconceptions and lack of knowledge of heat and temperature. Lastly, the following can be given as examples of students' misconceptions or lack of knowledge: they think temperature comes into being as a result of heat and that heat is a kind of energy.

Evaluation of structural design concepts for an arrow-wing supersonic cruise aircraft

NASA Technical Reports Server (NTRS)

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

1977-01-01

An analytical study was performed to determine the best structural approach for design of primary wing and fuselage structure of a Mach 2.7 arrow wing supersonic cruise aircraft. Concepts were evaluated considering near term start of design. Emphasis was placed on the complex interactions between thermal stress, static aeroelasticity, flutter, fatigue and fail safe design, static and dynamic loads, and the effects of variations in structural arrangements, concepts and materials on these interactions. Results indicate that a hybrid wing structure incorporating low profile convex beaded and honeycomb sandwich surface panels of titanium alloy 6Al-4V were the most efficient. The substructure includes titanium alloy spar caps reinforced with boron polyimide composites. The fuselage shell consists of hat stiffened skin and frame construction of titanium alloy 6Al-4V. A summary of the study effort is presented, and a discussion of the overall logic, design philosophy and interaction between the analytical methods for supersonic cruise aircraft design are included.

Performance of two load-limiting subfloor concepts in full-scale general aviation airplane crash tests

NASA Technical Reports Server (NTRS)

Carden, H. D.

1984-01-01

Three six-place, low wing, twin-engine general aviation airplane test specimens were crash tested at the langley Impact Dynamics research Facility under controlled free-flight conditions. One structurally unmodified airplane was the baseline airplane specimen for the test series. The other airplanes were structurally modified to incorporate load-limiting (energy-absorbing) subfloor concepts into the structure for full scale crash test evaluation and comparison to the unmodified airplane test results. Typically, the lowest floor accelerations and anthropomorphic dummy occupant responses, and the least seat crushing of standard and load-limiting seats, occurred in the modified load-limiting subfloor airplanes wherein the greatest structural crushing of the subfloor took place. The better performing of the two load-limiting subfloor concepts reduced the peak airplane floor accelerations at the pilot and four seat/occupant locations to -25 to -30 g's as compared to approximately -50 to -55 g's acceleration magnitude for the unmodified airplane structure.

Loading tests of a wing structure for a hypersonic aircraft

NASA Technical Reports Server (NTRS)

Fields, R. A.; Reardon, L. F.; Siegel, W. H.

1980-01-01

Room-temperature loading tests were conducted on a wing structure designed with a beaded panel concept for a Mach 8 hypersonic research airplane. Strain, stress, and deflection data were compared with the results of three finite-element structural analysis computer programs and with design data. The test program data were used to evaluate the structural concept and the methods of analysis used in the design. A force stiffness technique was utilized in conjunction with load conditions which produced various combinations of panel shear and compression loading to determine the failure envelope of the buckling critical beaded panels The force-stiffness data did not result in any predictions of buckling failure. It was, therefore, concluded that the panels were conservatively designed as a result of design constraints and assumptions of panel eccentricities. The analysis programs calculated strains and stresses competently. Comparisons between calculated and measured structural deflections showed good agreement. The test program offered a positive demonstration of the beaded panel concept subjected to room-temperature load conditions.

Structural tests and development of a laminar flow control wing surface composite chordwise joint

NASA Technical Reports Server (NTRS)

Lineberger, L. B.

1984-01-01

The dramatic increases in fuel costs and the potential for periods of limited fuel availability provided the impetus to explore technologies to reduce transport aircraft fuel consumption. NASA sponsored the Aircraft Energy Efficiency (ACEE) program beginning in 1976 to develop technologies to improve fuel efficiency. The Lockheed-Georgia Company accomplished under NAS1-16235 Laminar-Flow-Control (LFC) Wing Panel Structural Design and Development (WSSD); design, manufacturing, and testing activities. An in-depth preliminary design of the baseline 1993 LFC wing was accomplished. A surface panel using the Lockheed graphite/epoxy integrated LFC wing box structural concept was designed. The concept was shown by analysis to be structurally efficient and cost effective. Critical details of the surface and surface joint was demonstrated by fabricating and testing complex, concept selection specimens. The Lockheed-Georgia Company accomplishments, Development of LFC Wind Surface Composite Structures (WSCS), are documented. Tests were conducted on two CV2 panels to verify the static tension and fatigue strength of LFC wing surface chordwise joints.

ACT Payload Shroud Structural Concept Analysis and Optimization

NASA Technical Reports Server (NTRS)

Zalewski, Bart B.; Bednarcyk, Brett A.

2010-01-01

Aerospace structural applications demand a weight efficient design to perform in a cost effective manner. This is particularly true for launch vehicle structures, where weight is the dominant design driver. The design process typically requires many iterations to ensure that a satisfactory minimum weight has been obtained. Although metallic structures can be weight efficient, composite structures can provide additional weight savings due to their lower density and additional design flexibility. This work presents structural analysis and weight optimization of a composite payload shroud for NASA s Ares V heavy lift vehicle. Two concepts, which were previously determined to be efficient for such a structure are evaluated: a hat stiffened/corrugated panel and a fiber reinforced foam sandwich panel. A composite structural optimization code, HyperSizer, is used to optimize the panel geometry, composite material ply orientations, and sandwich core material. HyperSizer enables an efficient evaluation of thousands of potential designs versus multiple strength and stability-based failure criteria across multiple load cases. HyperSizer sizing process uses a global finite element model to obtain element forces, which are statistically processed to arrive at panel-level design-to loads. These loads are then used to analyze each candidate panel design. A near optimum design is selected as the one with the lowest weight that also provides all positive margins of safety. The stiffness of each newly sized panel or beam component is taken into account in the subsequent finite element analysis. Iteration of analysis/optimization is performed to ensure a converged design. Sizing results for the hat stiffened panel concept and the fiber reinforced foam sandwich concept are presented.

Optimization of an Advanced Hybrid Wing Body Concept Using HCDstruct Version 1.2

NASA Technical Reports Server (NTRS)

Quinlan, Jesse R.; Gern, Frank H.

2016-01-01

Hybrid Wing Body (HWB) aircraft concepts continue to be promising candidates for achieving the simultaneous fuel consumption and noise reduction goals set forth by NASA's Environmentally Responsible Aviation (ERA) project. In order to evaluate the projected benefits, improvements in structural analysis at the conceptual design level were necessary; thus, NASA researchers developed the Hybrid wing body Conceptual Design and structural optimization (HCDstruct) tool to perform aeroservoelastic structural optimizations of advanced HWB concepts. In this paper, the authors present substantial updates to the HCDstruct tool and related analysis, including: the addition of four inboard and eight outboard control surfaces and two all-movable tail/rudder assemblies, providing a full aeroservoelastic analysis capability; the implementation of asymmetric load cases for structural sizing applications; and a methodology for minimizing control surface actuation power using NASTRAN SOL 200 and HCDstruct's aeroservoelastic finite-element model (FEM).

A Study of the Development of the Concept of Mechanical Stability in Preschool Children

NASA Astrophysics Data System (ADS)

Hadzigeorgiou, Yannis

2002-06-01

The purpose of this study was to investigate whether preschool children (aged 4.5-6 years) can construct the concept of mechanical stability through structured hands-on activities involving the building of a tower on an inclined plane and through the use of cans of various sizes and weights. The data derived mainly from direct observation and the visual component of video tape recordings of thirty-seven children. These children formed three treatment groups which participated in structured-guided, structured-unguided and unstructured-unguided activities respectively. There is strong evidence that appropriately structured activities involving children's action on objects and the objects immediate reaction, as well as children's opportunity to vary this action, complemented with a scaffolding strategy can help children construct the concept of mechanical stability and apply it in other similar contexts. The paper also presents a theoretical framework for the teaching and learning of physics in the early years.

Concepts and analysis for precision segmented reflector and feed support structures

NASA Technical Reports Server (NTRS)

Miller, Richard K.; Thomson, Mark W.; Hedgepeth, John M.

1990-01-01

Several issues surrounding the design of a large (20-meter diameter) Precision Segmented Reflector are investigated. The concerns include development of a reflector support truss geometry that will permit deployment into the required doubly-curved shape without significant member strains. For deployable and erectable reflector support trusses, the reduction of structural redundancy was analyzed to achieve reduced weight and complexity for the designs. The stiffness and accuracy of such reduced member trusses, however, were found to be affected to a degree that is unexpected. The Precision Segmented Reflector designs were developed with performance requirements that represent the Reflector application. A novel deployable sunshade concept was developed, and a detailed parametric study of various feed support structural concepts was performed. The results of the detailed study reveal what may be the most desirable feed support structure geometry for Precision Segmented Reflector/Large Deployable Reflector applications.

Modeling patient safety incidents knowledge with the Categorial Structure method.

PubMed

Souvignet, Julien; Bousquet, Cédric; Lewalle, Pierre; Trombert-Paviot, Béatrice; Rodrigues, Jean Marie

2011-01-01

Following the WHO initiative named World Alliance for Patient Safety (PS) launched in 2004 a conceptual framework developed by PS national reporting experts has summarized the knowledge available. As a second step, the Department of Public Health of the University of Saint Etienne team elaborated a Categorial Structure (a semi formal structure not related to an upper level ontology) identifying the elements of the semantic structure underpinning the broad concepts contained in the framework for patient safety. This knowledge engineering method has been developed to enable modeling patient safety information as a prerequisite for subsequent full ontology development. The present article describes the semantic dissection of the concepts, the elicitation of the ontology requirements and the domain constraints of the conceptual framework. This ontology includes 134 concepts and 25 distinct relations and will serve as basis for an Information Model for Patient Safety.

Enabling Rapid and Robust Structural Analysis During Conceptual Design

NASA Technical Reports Server (NTRS)

Eldred, Lloyd B.; Padula, Sharon L.; Li, Wu

2015-01-01

This paper describes a multi-year effort to add a structural analysis subprocess to a supersonic aircraft conceptual design process. The desired capabilities include parametric geometry, automatic finite element mesh generation, static and aeroelastic analysis, and structural sizing. The paper discusses implementation details of the new subprocess, captures lessons learned, and suggests future improvements. The subprocess quickly compares concepts and robustly handles large changes in wing or fuselage geometry. The subprocess can rank concepts with regard to their structural feasibility and can identify promising regions of the design space. The automated structural analysis subprocess is deemed robust and rapid enough to be included in multidisciplinary conceptual design and optimization studies.

The structure and formation of natural categories

NASA Technical Reports Server (NTRS)

Fisher, Douglas; Langley, Pat

1990-01-01

Categorization and concept formation are critical activities of intelligence. These processes and the conceptual structures that support them raise important issues at the interface of cognitive psychology and artificial intelligence. The work presumes that advances in these and other areas are best facilitated by research methodologies that reward interdisciplinary interaction. In particular, a computational model is described of concept formation and categorization that exploits a rational analysis of basic level effects by Gluck and Corter. Their work provides a clean prescription of human category preferences that is adapted to the task of concept learning. Also, their analysis was extended to account for typicality and fan effects, and speculate on how the concept formation strategies might be extended to other facets of intelligence, such as problem solving.

Comparative analysis of on-orbit dynamic performance of several large antenna concepts

NASA Technical Reports Server (NTRS)

Andersen, G. C.; Garrett, L. B.; Calleson, R. E.

1985-01-01

A comparative analysis of the on-orbit dynamic performance of four large anetanna concepts is presented. Among the antenna concepts evaluated are: the box truss; tetrahedral truss; warp-radial rib; and the hoop and column antenna designs. The characteristics and magnitudes of the antennas' dynamic response were evaluated in terms of structural displacements and member loads incurred during various slew-rate maneuvers. The results of the dynamic response analysis are compared to the design requirements of the Land Mobile Satellite System (LMSS) with respect to surface accuracy, decenter, defocus, and angular rocking. Comments are made on the effectiveness of structural damping and the application of active controls for vibrational response reduction. Schematic illustrations of the antenna design concepts are provided.

Structural cost optimization of photovoltaic central power station modules and support structure

NASA Technical Reports Server (NTRS)

Sutton, P. D.; Stolte, W. J.; Marsh, R. O.

1979-01-01

The results of a comprehensive study of photovoltaic module structural support concepts for photovoltaic central power stations and their associated costs are presented. The objective of the study has been the identification of structural cost drivers. Parametric structural design and cost analyses of complete array systems consisting of modules, primary support structures, and foundations were performed. Area related module cost was found to be constant with design, size, and loading. A curved glass module concept was evaluated and found to have the potential to significantly reduce panel structural costs. Conclusions of the study are: array costs do not vary greatly among the designs evaluated; panel and array costs are strongly dependent on design loading; and the best support configuration is load dependent

n/a

NASA Image and Video Library

1985-11-01

The crew assigned to the STS-61B mission included (kneeling left to right) Bryan D. O’conner, pilot; and Brewster H. Shaw, commander. On the back row, left to right, are Charles D. Walker, payload specialist; mission specialists Jerry L. Ross, Mary L. Cleave, and Sherwood C. Spring; and Rodolpho Neri Vela, payload specialist. Launched aboard the Space Shuttle Atlantis November 28, 1985 at 7:29:00 pm (EST), the STS-61B mission’s primary payload included three communications satellites: MORELOS-B (Mexico); AUSSAT-2 (Autralia); and SATCOM KU-2 (RCA Americom. Two experiments were conducted to test assembling erectable structures in space: EASE (Experimental Assembly of Structures in Extravehicular Activity), and ACCESS (Assembly Concept for Construction of Erectable Space Structure). In a joint venture between NASA/Langley Research Center in Hampton, VA and Marshall Space Flight Center (MSFC), the Assembly Concept for Construction of Erectable Space Structures (ACCESS) was developed and demonstrated at MSFC's Neutral Buoyancy Simulator (NBS). The primary objective of this experiment was to test the ACCESS structural assembly concept for suitability as the framework for larger space structures and to identify ways to improve the productivity of space construction.

PACS—Realization of an adaptive concept using pressure actuated cellular structures

NASA Astrophysics Data System (ADS)

Gramüller, B.; Boblenz, J.; Hühne, C.

2014-10-01

A biologically inspired concept is investigated which can be utilized to develop energy efficient, lightweight and applicational flexible adaptive structures. Building a real life morphing unit is an ambitious task as the numerous works in the particular field show. Summarizing fundamental demands and barriers regarding shape changing structures, the basic challenges of designing morphing structures are listed. The concept of Pressure Actuated Cellular Structures (PACS) is arranged within the recent morphing activities and it is shown that it complies with the underlying demands. Systematically divided into energy-related and structural subcomponents the working principle is illuminated and relationships between basic design parameters are expressed. The analytical background describing the physical mechanisms of PACS is presented in concentrated manner. This work focuses on the procedure of dimensioning, realizing and experimental testing of a single cell and a single row cantilever made of PACS. The experimental outcomes as well as the results from the FEM computations are used for evaluating the analytical methods. The functionality of the basic principle is thus validated and open issues are determined pointing the way ahead.

STS-61B Crew Portrait

NASA Technical Reports Server (NTRS)

1985-01-01

The crew assigned to the STS-61B mission included (kneeling left to right) Bryan D. O'conner, pilot; and Brewster H. Shaw, commander. On the back row, left to right, are Charles D. Walker, payload specialist; mission specialists Jerry L. Ross, Mary L. Cleave, and Sherwood C. Spring; and Rodolpho Neri Vela, payload specialist. Launched aboard the Space Shuttle Atlantis November 28, 1985 at 7:29:00 pm (EST), the STS-61B mission's primary payload included three communications satellites: MORELOS-B (Mexico); AUSSAT-2 (Autralia); and SATCOM KU-2 (RCA Americom. Two experiments were conducted to test assembling erectable structures in space: EASE (Experimental Assembly of Structures in Extravehicular Activity), and ACCESS (Assembly Concept for Construction of Erectable Space Structure). In a joint venture between NASA/Langley Research Center in Hampton, VA and Marshall Space Flight Center (MSFC), the Assembly Concept for Construction of Erectable Space Structures (ACCESS) was developed and demonstrated at MSFC's Neutral Buoyancy Simulator (NBS). The primary objective of this experiment was to test the ACCESS structural assembly concept for suitability as the framework for larger space structures and to identify ways to improve the productivity of space construction.

Titanium and advanced composite structures for a supersonic cruise arrow wing configuration

NASA Technical Reports Server (NTRS)

Turner, M. J.; Hoy, J. M.

1976-01-01

Structural design studies were made, based on current technology and on an estimate of technology to be available in the mid 1980's, to assess the relative merits of structural concepts and materials for an advanced arrow wing configuration cruising at Mach 2.7. Preliminary studies were made to insure compliance of the configuration with general design criteria, integrate the propulsion system with the airframe, and define an efficient structural arrangement. Material and concept selection, detailed structural analysis, structural design and airplane mass analysis were completed based on current technology. Based on estimated future technology, structural sizing for strength and a preliminary assessment of the flutter of a strength designed composite structure were completed. An advanced computerized structural design system was used, in conjunction with a relatively complex finite element model, for detailed analysis and sizing of structural members.

Numerical modeling analysis of stress transfer modification concepts for deep longwall mines. Report of investigations/1995

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

Vandergrift, T.L.; Jude, C.V.

1995-12-31

This U.S. Bureau of Mines (USBM) report evaluates three stress-transfer-modification concepts for their potential in reducing longwall gate road stresses and closures. In each of the three concepts--packwalling, gob infilling, and entry filling--support structures are constructed on the headgate side of the panel parallel with or inby the face line. When the headgate becomes the tailgate of the adjacent panel, these structures are in place to accept stresses transferred from the mined-out panel. Using the USBM nonlinear boundary-element program MULSIM/NL, baseline models of typical longwall stress transfer behavior were developed for both intermediate depth and deep mining conditions. These modelsmore » were verified by comparing model results with field measurements and observations. The stress-transfer-modification concepts were then incorporated into the deep baseline model to quantify the effects of each concept on tailgate closure.« less

Development and Evaluation of an Adolescents' Depression Ontology for Analyzing Social Data.

PubMed

Jung, Hyesil; Park, Hyeoun-Ae; Song, Tae-Min

2016-01-01

This study aims to develop and evaluate an ontology for adolescents' depression to be used for collecting and analyzing social data. The ontology was developed according to the 'ontology development 101' methodology. Concepts were extracted from clinical practice guidelines and related literatures. The ontology is composed of five sub-ontologies which represent risk factors, sign and symptoms, measurement, diagnostic result and management care. The ontology was evaluated in four different ways: First, we examined the frequency of ontology concept appeared in social data; Second, the content coverage of ontology was evaluated by comparing ontology concepts with concepts extracted from the youth depression counseling records; Third, the structural and representational layer of the ontology were evaluated by 5 ontology and psychiatric nursing experts; Fourth, the scope of the ontology was examined by answering 59 competency questions. The ontology was improved by adding new concepts and synonyms and revising the level of structure.

Using Metaphorical Models for Describing Glaciers

ERIC Educational Resources Information Center

Felzmann, Dirk

2014-01-01

To date, there has only been little conceptual change research regarding conceptions about glaciers. This study used the theoretical background of embodied cognition to reconstruct different metaphorical concepts with respect to the structure of a glacier. Applying the Model of Educational Reconstruction, the conceptions of students and scientists…

Junior Secondary School Students' Conceptions about Plate Tectonics

ERIC Educational Resources Information Center

Mills, Reece; Tomas, Louisa; Lewthwaite, Brian

2017-01-01

There are ongoing calls for research that identifies students' conceptions about geographical phenomena. In response, this study investigates junior secondary school students' (N = 95) conceptions about plate tectonics. Student response data was generated from semi-structured interviews-about-instances and a two-tiered multiple-choice test…

Preservice Teachers' Professional Knowledge and Its Relation to Academic Self-Concept

ERIC Educational Resources Information Center

Paulick, Isabell; Großschedl, Jörg; Harms, Ute; Möller, Jens

2016-01-01

We investigated the factorial structure of preservice teachers' academic self-concept with regard to three domains of professional knowledge (content knowledge [CK], pedagogical content knowledge [PCK], and pedagogical/psychological knowledge [PPK]). We also analyzed the relation between preservice teachers' academic self-concept and their…

Structurally adaptive space crane concept for assembling space systems on orbit

NASA Technical Reports Server (NTRS)

Dorsey, John T.; Sutter, Thomas R.; Wu, K. Chauncey

1992-01-01

Many future human space exploration missions will probably require large vehicles that must be assembled on orbit. Thus, a device that can move, position, and assemble large and massive spacecraft components on orbit becomes essential for these missions. A concept is described for such a device: a space crane concept that uses erectable truss hardware to achieve high-stiffness and low-mass booms and uses articulating truss joints that can be assembled on orbit. The hardware has been tested and shown to have linear load-deflection response and to be structurally predictable. The hardware also permits the crane to be reconfigured into different geometries to satisfy future assembly requirements. A number of articulating and rotary joint concepts have been sized and analyzed, and the results are discussed. Two strategies were proposed to suppress motion-induced vibration: placing viscous dampers in selected truss struts and preshaping motion commands. Preliminary analyses indicate that these techniques have the potential to greatly enhance structural damping.

Double-scattering/reflection in a Single Nanoparticle for Intensified Ultrasound Imaging

PubMed Central

Zhang, Kun; Chen, Hangrong; Guo, Xiasheng; Zhang, Dong; Zheng, Yuanyi; Zheng, Hairong; Shi, Jianlin

2015-01-01

Ultrasound contrast agents (UCAs) designed by the conventional composition-based strategy, often suffer from relatively low ultrasound utilization efficiency. In this report, a structure-based design concept of double-scattering/reflection in a single nanoparticle for enhancing ultrasound imaging has been proposed. To exemplify this concept, a rattle-type mesoporous silica nanostructure (MSN) with two contributing interfaces has been employed as the ideal model. Contributed by double-scattering/reflection interfaces, the rattle-type MSN, as expected, performs much better in in vitro and in vivo ultrasound imaging than the other two nanostructures (solid and hollow) containing only one scattering/reflection interface. More convincingly, related acoustic measurements and simulation calculations also confirm this design concept. Noticeably, the rattle-type MSN has also been demonstrated capable of improving intracellular ultrasound molecular imaging. As a universal method, the structure-design concept can extend to guide the design of new generation UCAs with many other compositions and similar structures (e.g., heterogeneous rattle-type, double-shelled). PMID:25739832

Does the concept of Clar's aromatic sextet work for dicationic forms of polycyclic aromatic hydrocarbons?--testing the model against charged systems in singlet and triplet states.

PubMed

Dominikowska, Justyna; Palusiak, Marcin

2011-07-07

The concept of Clar's π-electron aromatic sextet was tested against a set of polycyclic aromatic hydrocarbons in neutral and doubly charged forms. Systems containing different types of rings (in the context of Clar's concept) were chosen, including benzene, naphthalene, anthracene, phenanthrene and triphenylene. In the case of dicationic structures both singlet and triplet states were considered. It was found that for singlet state dicationic structures the concept of aromatic sextet could be applied and the local aromaticity could be discussed in the context of that model, whereas in the case of triplet state dicationic structures Clar's model rather failed. Different aromaticity indices based on various properties of molecular systems were applied for the purpose of the studies. The discussion about the interdependence between the values of different aromaticity indices applied to neutral and charged systems in singlet and triplet states is also included. This journal is © the Owner Societies 2011

Safer Conception for Couples Affected by HIV: Structural and Cultural Considerations in the Delivery of Safer Conception Care in Uganda.

PubMed

Mindry, Deborah; Wanyenze, Rhoda K; Beyeza-Kashesya, Jolly; Woldetsadik, Mahlet A; Finocchario-Kessler, Sarah; Goggin, Kathy; Wagner, Glenn

2017-08-01

In countries with high HIV prevalence and high fertility desires, the rights of HIV-affected couples to have children are a pressing issue. Conception among people living with HIV carries risks for both horizontal and vertical HIV transmission. In Uganda ~100,000 HIV-infected women become pregnant annually. Providers face a number of challenges to preventing HIV transmission, reducing unplanned pregnancies, and ensuring safer conception. We report findings from interviews with 27 HIV-affected couples (54 individuals) in Uganda. We explored key cultural and structural factors shaping couples' childbearing decisions. Our data reveal a complex intersection of gender norms, familial expectations, relationship dynamics, and HIV stigma influencing their decisions. Participants provided insights regarding provider bias, stigma, and the gendering of reproductive healthcare. To reduce horizontal transmission HIV and family planning clinics must address men's and women's concerns regarding childbearing with specific attention to cultural and structural challenges.

Double-scattering/reflection in a single nanoparticle for intensified ultrasound imaging.

PubMed

Zhang, Kun; Chen, Hangrong; Guo, Xiasheng; Zhang, Dong; Zheng, Yuanyi; Zheng, Hairong; Shi, Jianlin

2015-03-05

Ultrasound contrast agents (UCAs) designed by the conventional composition-based strategy, often suffer from relatively low ultrasound utilization efficiency. In this report, a structure-based design concept of double-scattering/reflection in a single nanoparticle for enhancing ultrasound imaging has been proposed. To exemplify this concept, a rattle-type mesoporous silica nanostructure (MSN) with two contributing interfaces has been employed as the ideal model. Contributed by double-scattering/reflection interfaces, the rattle-type MSN, as expected, performs much better in in vitro and in vivo ultrasound imaging than the other two nanostructures (solid and hollow) containing only one scattering/reflection interface. More convincingly, related acoustic measurements and simulation calculations also confirm this design concept. Noticeably, the rattle-type MSN has also been demonstrated capable of improving intracellular ultrasound molecular imaging. As a universal method, the structure-design concept can extend to guide the design of new generation UCAs with many other compositions and similar structures (e.g., heterogeneous rattle-type, double-shelled).

Analytical and experimental investigation of aircraft metal structures reinforced with filamentary composites. Phase 1: Concept development and feasibility

NASA Technical Reports Server (NTRS)

Oken, S.; June, R. R.

1971-01-01

The analytical and experimental investigations are described in the first phase of a program to establish the feasibility of reinforcing metal aircraft structures with advanced filamentary composites. The interactions resulting from combining the two types of materials into single assemblies as well as their ability to function structurally were studied. The combinations studied were boron-epoxy reinforced aluminum, boron-epoxy reinforced titanium, and boron-polyimide reinforced titanium. The concepts used unidirectional composites as reinforcement in the primary loading direction and metal for carrying the transverse loads as well as its portion of the primary load. The program established that several realistic concepts could be fabricated, that these concepts could perform to a level that would result in significant weight savings, and that there are means for predicting their capability within a reasonable degree of accuracy. This program also encountered problems related to the application of polyimide systems that resulted in their relatively poor and variable performance.

Technical and Economic Assessment of Span-Loaded Cargo Aircraft Concepts

NASA Technical Reports Server (NTRS)

1976-01-01

The benefits are assessed of span distributed loading concepts as applied to future commercial air cargo operations. A two phased program is used to perform this assessment. The first phase consists of selected parametric studies to define significant configuration, performance, and economic trends. The second phase consists of more detailed engineering design, analysis, and economic evaluations to define the technical and economic feasibility of a selected spanloader design. A conventional all-cargo aircraft of comparable technology and size is used as a comparator system. The technical feasibility is demonstrated of the spanloader concept with no new major technology efforts required to implement the system. However, certain high pay-off technologies such as winglets, airfoil design, and advanced structural materials and manufacturing techniques need refinement and definition prior to application. In addition, further structural design analysis could establish the techniques and criteria necessary to fully capitalize upon the high degree of structural commonality and simplicity inherent in the spanloader concept.

Towards new understanding of the heart structure and function.

PubMed

Torrent-Guasp, Francisco; Kocica, Mladen J; Corno, Antonio F; Komeda, Masashi; Carreras-Costa, Francesc; Flotats, A; Cosin-Aguillar, Juan; Wen, Han

2005-02-01

Structure and function in any organ are inseparable categories, both in health and disease. Whether we are ready to accept, or not, many questions in cardiovascular medicine are still pending, due to our insufficient insight in the basic science. Even so, any new concept encounters difficulties, mainly arising from our inert attitude, which may result either in unjustified acceptance or denial. The ventricular myocardial band concept, developed over the last 50 years, has revealed unavoidable coherence and mutual coupling of form and function in the ventricular myocardium. After more than five centuries long debate on macroscopic structure of the ventricular myocardium, this concept has provided a promising ground for its final understanding. Recent validations of the ventricular myocardial band, reviewed here, as well as future research directions that are pointed out, should initiate much wider scientific interest, which would, in turn, lead to reconciliation of some exceeded concepts about developmental, electrical, mechanical and energetical events in human heart. The benefit of this, of course, would be the most evident in the clinical arena.

Crack Detection in Fibre Reinforced Plastic Structures Using Embedded Fibre Bragg Grating Sensors: Theory, Model Development and Experimental Validation

PubMed Central

Pereira, G. F.; Mikkelsen, L. P.; McGugan, M.

2015-01-01

In a fibre-reinforced polymer (FRP) structure designed using the emerging damage tolerance and structural health monitoring philosophy, sensors and models that describe crack propagation will enable a structure to operate despite the presence of damage by fully exploiting the material’s mechanical properties. When applying this concept to different structures, sensor systems and damage types, a combination of damage mechanics, monitoring technology, and modelling is required. The primary objective of this article is to demonstrate such a combination. This article is divided in three main topics: the damage mechanism (delamination of FRP), the structural health monitoring technology (fibre Bragg gratings to detect delamination), and the finite element method model of the structure that incorporates these concepts into a final and integrated damage-monitoring concept. A novel method for assessing a crack growth/damage event in fibre-reinforced polymer or structural adhesive-bonded structures using embedded fibre Bragg grating (FBG) sensors is presented by combining conventional measured parameters, such as wavelength shift, with parameters associated with measurement errors, typically ignored by the end-user. Conjointly, a novel model for sensor output prediction (virtual sensor) was developed using this FBG sensor crack monitoring concept and implemented in a finite element method code. The monitoring method was demonstrated and validated using glass fibre double cantilever beam specimens instrumented with an array of FBG sensors embedded in the material and tested using an experimental fracture procedure. The digital image correlation technique was used to validate the model prediction by correlating the specific sensor response caused by the crack with the developed model. PMID:26513653

A knowledge representation view on biomedical structure and function.

PubMed Central

Schulz, Stefan; Hahn, Udo

2002-01-01

In biomedical ontologies, structural and functional considerations are of outstanding importance, and concepts which belong to these two categories are highly interdependent. At the representational level both axes must be clearly kept separate in order to support disciplined ontology engineering. Furthermore, the biaxial organization of physical structure (both by a taxonomic and partonomic order) entails intricate patterns of inference. We here propose a layered encoding of taxonomic, partonomic and functional aspects of biomedical concepts using description logics. PMID:12463912

Preliminary space station solar array structural design study

NASA Technical Reports Server (NTRS)

Dorsey, J. T.; Bush, H. G.; Mikulas, M. M., Jr.

1984-01-01

Structurally efficient ways to support the large solar arrays (3,716 square meters which are currently considered for space station use) are examined. An erectable truss concept is presented for the on orbit construction of winged solar arrays. The means for future growth, maintenance, and repair are integrally designed into this concept. Results from parametric studies, which highlight the physical and structural differences between various configuration options are presented. Consideration is given to both solar blanket and hard panel arrays.

Large space structures and systems in the space station era: A bibliography with indexes

NASA Technical Reports Server (NTRS)

Ferrainolo, John J. (Compiler); Lawrence, George F. (Compiler)

1991-01-01

Bibliographies and abstracts are listed for 1219 reports, articles, and other documents introduced into the NASA scientific and technical information system between July 1, 1990 and December 31, 1990. The purpose is to provide helpful information to the researcher, manager, and designer in technology development and mission design according to system, interactive analysis and design, structural and thermal analysis and design, structural concepts and control systems, electronics, advanced materials, assembly concepts, propulsion, and solar power satellite systems.

Large space structures and systems in the space station era: A bibliography with indexes

NASA Technical Reports Server (NTRS)

Ferrainolo, John J. (Editor)

1990-01-01

Bibliographies and abstracts are listed for 1372 reports, articles, and other documents introduced into the NASA scientific and technical information system between January 1, 1990 and June 30, 1990. Its purpose is to provide helpful information to the researcher, manager, and designer in technology development and mission design according to system, interactive analysis and design, structural and thermal analysis and design, structural concepts and control systems, electronics, advanced materials, assembly concepts, propulsion, and solar power satellite systems.

Preliminary space station solar array structural design study

NASA Astrophysics Data System (ADS)

Dorsey, J. T.; Bush, H. G.; Mikulas, M. M., Jr.

Structurally efficient ways to support the large solar arrays (3,716 square meters which are currently considered for space station use) are examined. An erectable truss concept is presented for the on orbit construction of winged solar arrays. The means for future growth, maintenance, and repair are integrally designed into this concept. Results from parametric studies, which highlight the physical and structural differences between various configuration options are presented. Consideration is given to both solar blanket and hard panel arrays.

[Organization of clinical emergency units. Mission and environmental factors determine the organizational concept].

PubMed

Genewein, U; Jakob, M; Bingisser, R; Burla, S; Heberer, M

2009-02-01

Mission and organization of emergency units were analysed to understand the underlying principles and concepts. The recent literature (2000-2007) on organizational structures and functional concepts of clinical emergency units was reviewed. An organizational portfolio based on the criteria specialization (presence of medical specialists on the emergency unit) and integration (integration of the emergency unit into the hospital structure) was established. The resulting organizational archetypes were comparatively assessed based on established efficiency criteria (efficiency of resource utilization, process efficiency, market efficiency). Clinical emergency units differ with regard to autonomy (within the hospital structure), range of services and service depth (horizontal and vertical integration). The "specialization"-"integration"-portfolio enabled the definition of typical organizational patterns (so-called archetypes): profit centres primarily driven by economic objectives, service centres operating on the basis of agreements with the hospital board, functional clinical units integrated into medical specialty units (e.g., surgery, gynaecology) and modular organizations characterized by small emergency teams that would call specialists immediately after triage and initial diagnostic. There is no "one fits all" concept for the organization of clinical emergency units. Instead, a number of well characterized organizational concepts are available enabling a rational choice based on a hospital's mission and demand.

A method of searching for related literature on protein structure analysis by considering a user's intention

PubMed Central

2015-01-01

Background In recent years, with advances in techniques for protein structure analysis, the knowledge about protein structure and function has been published in a vast number of articles. A method to search for specific publications from such a large pool of articles is needed. In this paper, we propose a method to search for related articles on protein structure analysis by using an article itself as a query. Results Each article is represented as a set of concepts in the proposed method. Then, by using similarities among concepts formulated from databases such as Gene Ontology, similarities between articles are evaluated. In this framework, the desired search results vary depending on the user's search intention because a variety of information is included in a single article. Therefore, the proposed method provides not only one input article (primary article) but also additional articles related to it as an input query to determine the search intention of the user, based on the relationship between two query articles. In other words, based on the concepts contained in the input article and additional articles, we actualize a relevant literature search that considers user intention by varying the degree of attention given to each concept and modifying the concept hierarchy graph. Conclusions We performed an experiment to retrieve relevant papers from articles on protein structure analysis registered in the Protein Data Bank by using three query datasets. The experimental results yielded search results with better accuracy than when user intention was not considered, confirming the effectiveness of the proposed method. PMID:25952498

Engineering principles to assure compatible docking between future spacecraft of USA and USSR

NASA Technical Reports Server (NTRS)

Johnson, C. C.

1973-01-01

An androgynous peripheral type docking mechanism concept selected by the U.S. and the USSR is described. The rationale supporting the selection of the concept, the mechanical principles inherent to the concept, and the probable nature of future designs stemming from the concept are discussed. Operational situations prior to docking, impact conditions, energy absorption, and structural joining of two spacecraft are examined.

Pre-Service Physics Teachers' Understanding of the Relational Structure of Physics Concepts: Organising Subject Contents for Purposes of Teaching

ERIC Educational Resources Information Center

Koponen, Ismo; Nousiainen, Maija

2013-01-01

Good conceptual understanding of physics is based on understanding what the key concepts are and how they are related. This kind of understanding is especially important for physics teachers in planning how and in what order to introduce concepts in teaching; connections which tie concepts to each other give direction of progress--there is "flux…

Supporting Students in Learning with Multiple Representation to Improve Student Mental Models on Atomic Structure Concepts

ERIC Educational Resources Information Center

Sunyono; Yuanita, L.; Ibrahim, M.

2015-01-01

The aim of this research is identify the effectiveness of a multiple representation-based learning model, which builds a mental model within the concept of atomic structure. The research sample of 108 students in 3 classes is obtained randomly from among students of Mathematics and Science Education Studies using a stratified random sampling…

Building Capacity in Understanding Foundational Biology Concepts: A K-12 Learning Progression in Genetics Informed by Research on Children's Thinking and Learning

ERIC Educational Resources Information Center

Elmesky, Rowhea

2013-01-01

This article describes the substance, structure, and rationale of a learning progression in genetics spanning kindergarten through twelfth grade (K-12). The learning progression is designed to build a foundation towards understanding protein structure and activity and should be viewed as one possible pathway to understanding concepts of genetics…

Investigating High-School Chemical Kinetics: The Greek Chemistry Textbook and Students' Difficulties

ERIC Educational Resources Information Center

Gegios, Theodoros; Salta, Katerina; Koinis, Spyros

2017-01-01

In this study we present an analysis of how the structure and content of the Greek school textbook approaches the concepts of chemical kinetics, and an investigation of the difficulties that 11th grade Greek students face regarding these concepts. Based on the structure and content of the Greek textbook, a tool was developed and applied to…

Effects of a Structured Resource-Based Web Issue-Quest Approach on Students' Learning Performances in Computer Programming Courses

ERIC Educational Resources Information Center

Hsu, Ting-Chia; Hwang, Gwo-Jen

2017-01-01

Programming concepts are important and challenging to novices who are beginning to study computer programming skills. In addition to the textbook content, students usually learn the concepts of programming from the web; however, it could be difficult for novice learners to effectively derive helpful information from such non-structured open…

Teaching Basic Science Environmentally, The Concept: The cell is basic unit of structure of most organisms.

ERIC Educational Resources Information Center

Busch, Phyllis S.

1985-01-01

Suggests simple ways to introduce students to the concept that the cell is the basic unit of structure of most organisms. Mentions materials for microscope study that are readily available and easy to handle, e.g., membranes from between the scales of the onion bulb, thin-leaved plants, pond water, and pollen. (JHZ)

Effects of Prior Knowledge and Concept-Map Structure on Disorientation, Cognitive Load, and Learning

ERIC Educational Resources Information Center

Amadieu, Franck; van Gog, Tamara; Paas, Fred; Tricot, Andre; Marine, Claudette

2009-01-01

This study explored the effects of prior knowledge (high vs. low; HPK and LPK) and concept-map structure (hierarchical vs. network; HS and NS) on disorientation, cognitive load, and learning from non-linear documents on "the infection process of a retrograde virus (HIV)". Participants in the study were 24 adults. Overall subjective ratings of…

Development of Thermally Actuated, High-Temperature Composite Morphing Concepts

DTIC Science & Technology

2016-05-11

Thermally Actuated, High- Temperature Composite Morphing Concepts 5a. CONTRACT NUMBER EOARD 14-0063 5b. GRANT NUMBER FA9550-14-1-0063 5c...mismatched thermal expansion coefficients. However, current bimorphs are generally limited to benign temperatures and linear temperature displacement... temperature morphing structures. Successful application of this work may yield morphing hot structures in extreme environments. A particularly appealing

Development of Thermally Actuated, High Temperature Composite Morphing Concepts

DTIC Science & Technology

2016-03-31

Thermally Actuated, High- Temperature Composite Morphing Concepts 5a. CONTRACT NUMBER EOARD 14-0063 5b. GRANT NUMBER FA9550-14-1-0063 5c...mismatched thermal expansion coefficients. However, current bimorphs are generally limited to benign temperatures and linear temperature displacement... temperature morphing structures. Successful application of this work may yield morphing hot structures in extreme environments. A particularly appealing

Developing Algebra Structure Module and Model of Cooperative Learning Helping Concept Map Media for Improving Proofing Ability

ERIC Educational Resources Information Center

Syafari

2017-01-01

This research was purposed to develop module and learning model and instrument of proofing ability in algebra structure through cooperative learning with helping map concept media for students of mathematic major and mathematics education in State University and Private University in North Sumatra province. The subject of this research was the…

Thermostructural analysis of a scramjet fuel-injection strut

NASA Technical Reports Server (NTRS)

Wieting, A. R.; Thornton, E. A.

1978-01-01

Results of a thermal/structural design analysis study of a fuel injection strut for an airframe integrated hydrogen cooled scramjet are presented. It is indicated that a feasible thermal/structural concept has been identified for the static load conditions and that thermal stresses dominate the response. It is suggested that the response of the concept to dynamic loads be investigated.

Nondestructive Evaluation (NDE) Results on Sikorsky Aircraft Survivable Affordable Reparable Airframe Program (SARAP) Samples

NASA Technical Reports Server (NTRS)

Zalameda, Joseph N.; Anastasi, Robert F.; Madaras, Eric I.

2004-01-01

The Survivable, Affordable, Reparable Airframe Program (SARAP) will develop/produce new structural design concepts with lower structural weight, reduced manufacturing complexity and development time, increased readiness, and improved threat protection. These new structural concepts will require advanced field capable inspection technologies to help meet the SARAP structural objectives. In the area of repair, damage assessment using nondestructive inspection (NDI) is critical to identify repair location and size. The purpose of this work is to conduct an assessment of new and emerging NDI methods that can potentially satisfy the SARAP program goals.

Study for identification of Beneficial Uses of Space (BUS). Volume 2: Technical report. Book 5: Study methods and trade studies

NASA Technical Reports Server (NTRS)

1975-01-01

A glossary of terms, a work breakdown structure, and work element descriptions, resource needs, and costs are introduced. The generic work breakdown structure was utilized to organize specific structures for each product under study; each structure containing both space and ground elements arrived at via mutual interaction. Concept definition and assessment, provided the study team and the participants visibility of the limits, and the organization of the efforts provided by both groups spelling out where such efforts fit into the generation of processing concepts.

The Structure Lacuna

PubMed Central

Boeyens, Jan C.A.; Levendis, Demetrius C.

2012-01-01

Molecular symmetry is intimately connected with the classical concept of three-dimensional molecular structure. In a non-classical theory of wave-like interaction in four-dimensional space-time, both of these concepts and traditional quantum mechanics lose their operational meaning, unless suitably modified. A required reformulation should emphasize the importance of four-dimensional effects like spin and the symmetry effects of space-time curvature that could lead to a fundamentally different understanding of molecular symmetry and structure in terms of elementary number theory. Isolated single molecules have no characteristic shape and macro-biomolecules only develop robust three-dimensional structure in hydrophobic response to aqueous cellular media. PMID:22942753

An interdisciplinary team communication framework and its application to healthcare 'e-teams' systems design

PubMed Central

2009-01-01

Background There are few studies that examine the processes that interdisciplinary teams engage in and how we can design health information systems (HIS) to support those team processes. This was an exploratory study with two purposes: (1) To develop a framework for interdisciplinary team communication based on structures, processes and outcomes that were identified as having occurred during weekly team meetings. (2) To use the framework to guide 'e-teams' HIS design to support interdisciplinary team meeting communication. Methods An ethnographic approach was used to collect data on two interdisciplinary teams. Qualitative content analysis was used to analyze the data according to structures, processes and outcomes. Results We present details for team meta-concepts of structures, processes and outcomes and the concepts and sub concepts within each meta-concept. We also provide an exploratory framework for interdisciplinary team communication and describe how the framework can guide HIS design to support 'e-teams'. Conclusion The structures, processes and outcomes that describe interdisciplinary teams are complex and often occur in a non-linear fashion. Electronic data support, process facilitation and team video conferencing are three HIS tools that can enhance team function. PMID:19754966

An interdisciplinary team communication framework and its application to healthcare 'e-teams' systems design.

PubMed

Kuziemsky, Craig E; Borycki, Elizabeth M; Purkis, Mary Ellen; Black, Fraser; Boyle, Michael; Cloutier-Fisher, Denise; Fox, Lee Ann; MacKenzie, Patricia; Syme, Ann; Tschanz, Coby; Wainwright, Wendy; Wong, Helen

2009-09-15

There are few studies that examine the processes that interdisciplinary teams engage in and how we can design health information systems (HIS) to support those team processes. This was an exploratory study with two purposes: (1) To develop a framework for interdisciplinary team communication based on structures, processes and outcomes that were identified as having occurred during weekly team meetings. (2) To use the framework to guide 'e-teams' HIS design to support interdisciplinary team meeting communication. An ethnographic approach was used to collect data on two interdisciplinary teams. Qualitative content analysis was used to analyze the data according to structures, processes and outcomes. We present details for team meta-concepts of structures, processes and outcomes and the concepts and sub concepts within each meta-concept. We also provide an exploratory framework for interdisciplinary team communication and describe how the framework can guide HIS design to support 'e-teams'. The structures, processes and outcomes that describe interdisciplinary teams are complex and often occur in a non-linear fashion. Electronic data support, process facilitation and team video conferencing are three HIS tools that can enhance team function.

Investigation of Exoskeletal Engine Propulsion System Concept

NASA Technical Reports Server (NTRS)

Roche, Joseph M.; Palac, Donald T.; Hunter, James E.; Myers, David E.; Snyder, Christopher A.; Kosareo, Daniel N.; McCurdy, David R.; Dougherty, Kevin T.

2005-01-01

An innovative approach to gas turbine design involves mounting compressor and turbine blades to an outer rotating shell. Designated the exoskeletal engine, compression (preferable to tension for high-temperature ceramic materials, generally) becomes the dominant blade force. Exoskeletal engine feasibility lies in the structural and mechanical design (as opposed to cycle or aerothermodynamic design), so this study focused on the development and assessment of a structural-mechanical exoskeletal concept using the Rolls-Royce AE3007 regional airliner all-axial turbofan as a baseline. The effort was further limited to the definition of an exoskeletal high-pressure spool concept, where the major structural and thermal challenges are represented. The mass of the high-pressure spool was calculated and compared with the mass of AE3007 engine components. It was found that the exoskeletal engine rotating components can be significantly lighter than the rotating components of a conventional engine. However, bearing technology development is required, since the mass of existing bearing systems would exceed rotating machinery mass savings. It is recommended that once bearing technology is sufficiently advanced, a "clean sheet" preliminary design of an exoskeletal system be accomplished to better quantify the potential for the exoskeletal concept to deliver benefits in mass, structural efficiency, and cycle design flexibility.

Hybrid Piezoelectric/Fiber-Optic Sensor Sheets

NASA Technical Reports Server (NTRS)

Lin, Mark; Qing, Xinlin

2004-01-01

Hybrid piezoelectric/fiber-optic (HyPFO) sensor sheets are undergoing development. They are intended for use in nondestructive evaluation and long-term monitoring of the integrity of diverse structures, including aerospace, aeronautical, automotive, and large stationary ones. It is anticipated that the further development and subsequent commercialization of the HyPFO sensor systems will lead to economic benefits in the form of increased safety, reduction of life-cycle costs through real-time structural monitoring, increased structural reliability, reduction of maintenance costs, and increased readiness for service. The concept of a HyPFO sensor sheet is a generalization of the concept of a SMART Layer(TradeMark), which is a patented device that comprises a thin dielectric film containing an embedded network of distributed piezoelectric actuator/sensors. Such a device can be mounted on the surface of a metallic structure or embedded inside a composite-material structure during fabrication of the structure. There is has been substantial interest in incorporating sensors other than piezoelectric ones into SMART Layer(TradeMark) networks: in particular, because of the popularity of the use of fiber-optic sensors for monitoring the "health" of structures in recent years, it was decided to incorporate fiber-optic sensors, giving rise to the concept of HyPFO devices.

Nonlinear Structural Analysis Methodology and Dynamics Scaling of Inflatable Parabolic Reflector Antenna Concepts

NASA Technical Reports Server (NTRS)

Sreekantamurthy, Tham; Gaspar, James L.; Mann, Troy; Behun, Vaughn; Pearson, James C., Jr.; Scarborough, Stephen

2007-01-01

Ultra-light weight and ultra-thin membrane inflatable antenna concepts are fast evolving to become the state-of-the-art antenna concepts for deep-space applications. NASA Langley Research Center has been involved in the structural dynamics research on antenna structures. One of the goals of the research is to develop structural analysis methodology for prediction of the static and dynamic response characteristics of the inflatable antenna concepts. This research is focused on the computational studies to use nonlinear large deformation finite element analysis to characterize the ultra-thin membrane responses of the antennas. Recently, structural analyses have been performed on a few parabolic reflector antennas of varying size and shape, which are referred in the paper as 0.3 meters subscale, 2 meters half-scale, and 4 meters full-scale antenna. The various aspects studied included nonlinear analysis methodology and solution techniques, ways to speed convergence in iterative methods, the sensitivities of responses with respect to structural loads, such as inflation pressure, gravity, and pretension loads in the ground and in-space conditions, and the ultra-thin membrane wrinkling characteristics. Several such intrinsic aspects studied have provided valuable insight into evaluation of structural characteristics of such antennas. While analyzing these structural characteristics, a quick study was also made to assess the applicability of dynamics scaling of the half-scale antenna. This paper presents the details of the nonlinear structural analysis results, and discusses the insight gained from the studies on the various intrinsic aspects of the analysis methodology. The predicted reflector surface characteristics of the three inflatable ultra-thin membrane parabolic reflector antenna concepts are presented as easily observable displacement fringe patterns with associated maximum values, and normal mode shapes and associated frequencies. Wrinkling patterns are presented to show how surface wrinkle progress with increasing tension loads. Antenna reflector surface accuracies were found to be very much dependent on the type and size of the antenna, the reflector surface curvature, reflector membrane supports in terms of spacing of catenaries, as well as the amount of applied load.

Evaluation of Students' Understanding of Thermal Concepts in Everyday Contexts

ERIC Educational Resources Information Center

Chu, Hye-Eun; Treagust, David F.; Yeo, Shelley; Zadnik, Marjan

2012-01-01

The aims of this study were to determine the underlying conceptual structure of the thermal concept evaluation (TCE) questionnaire, a pencil-and-paper instrument about everyday contexts of heat, temperature, and heat transfer, to investigate students' conceptual understanding of thermal concepts in everyday contexts across several school years and…

Technology for large space systems: A special bibliography with indexes (supplement 03)

NASA Technical Reports Server (NTRS)

1980-01-01

A bibliography containing 217 abstracts addressing the technology for large space systems is presented. State of the art and advanced concepts concerning interactive analysis and design, structural concepts, control systems, electronics, advanced materials, assembly concepts, propulsion, solar power satellite systems, and flight experiments are represented.

Universal Cable Brackets

NASA Technical Reports Server (NTRS)

Vanvalkenburgh, C.

1985-01-01

Concept allows routing easily changed. No custom hardware required in concept. Instead, standard brackets cut to length and installed at selected locations along cable route. If cable route is changed, brackets simply moved to new locations. Concept for "universal" cable brackets make it easy to route electrical cable around and through virtually any structure.

An Empirical Exploration of Metacognitive Assessment Activities in a Third-Year Civil Engineering Hydraulics Course

ERIC Educational Resources Information Center

Meyer, Jan H. F.; Knight, David B.; Callaghan, David P.; Baldock, Tom E.

2015-01-01

Threshold concepts are transformative, integrative, and provocative; understanding these difficult concepts allows students to be capable of solving advanced problems. This investigation and evaluation of a metacognitive curricular approach explore variation in students' and teachers' discernment of structural complexity of concepts and its…

Teachers' Conceptions of Excellent Teaching and Its Relationships to Self-Reported Teaching Practices

ERIC Educational Resources Information Center

Chen, Junjun; Brown, Gavin T. L.; Hattie, John A. C.; Millward, Pam

2012-01-01

This study surveyed Chinese middle school (n = 951) teachers' conceptions of excellent teaching and examined the relationship of those conceptions to their self-reported teaching practices. Responses were analyzed using confirmatory factor analysis and structural equation modeling. These teachers identified one examination-oriented dimension and…

Opening the World of Mathematics: The Daily Math Discussion

ERIC Educational Resources Information Center

Donoahue, Zoe

2016-01-01

During the author's everyday math discussions with her class, young children talk about mathematical ideas, theories, and concepts within a predictable structure. These discussions include many concepts from--and beyond--the first-grade math curriculum, and their depth and complexity build throughout the school year. Concepts and skills include…

Conceptions, Self-Regulation, and Strategies of Learning Science among Chinese High School Students

ERIC Educational Resources Information Center

Li, Mang; Zheng, Chunping; Liang, Jyh-Chong; Zhang, Yun; Tsai, Chin-Chung

2018-01-01

This study explored the structural relationships among secondary school students' conceptions, self-regulation, and strategies of learning science in mainland China. Three questionnaires, namely conceptions of learning science (COLS), self-regulation of learning science (SROLS), and strategies of learning science (SLS) were developed for…

A Vision of Improvement of Learning: South African Teachers' Conceptions of Classroom Assessment

ERIC Educational Resources Information Center

Sethusha, Mantsose Jane

2013-01-01

This article explored conceptions that teachers hold about classroom assessment and how these conceptions influence their classroom assessment practices. The qualitative study employed a case study approach. Semi-structured interviews, observations and document analyses were used. The study utilized Brown's (2004) conceptual framework on…

Arrow-wing supersonic cruise aircraft structural design concepts evaluation. Volume 1: Sections 1 through 6

NASA Technical Reports Server (NTRS)

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

1975-01-01

The structural approach best suited for the design of a Mach 2.7 arrow-wing supersonic cruise aircraft was investigated. Results, procedures, and principal justification of results are presented. Detailed substantiation data are given. In general, each major analysis is presented sequentially in separate sections to provide continuity in the flow of the design concepts analysis effort. In addition to the design concepts evaluation and the detailed engineering design analyses, supporting tasks encompassing: (1) the controls system development; (2) the propulsion-airframe integration study; and (3) the advanced technology assessment are presented.

Structural concepts for large solar concentrators

NASA Technical Reports Server (NTRS)

Hedgepeth, J. M.; Miller, R. K.

1986-01-01

Solar collectors for space use are examined, including both early designs and current concepts. In particular, attention is given to stiff sandwich panels and aluminum dishes as well as inflated and umbrella-type membrane configurations. The Sunflower concentrator is described as an example of a high-efficiency collector. It is concluded that stiff reflector panels are most likely to provide the long-term consistent accuracy necessary for low-orbit operation. A new configuration consisting of a Pactruss backup structure, with identical panels installed after deployment in space, is presented. It is estimated that concentration ratios in excess of 2000 can be achieved with this concept.

Some Lower Valence Vanadium Fluorides: Their Crystal Distortions, Domain Structures, Modulated Structures, Ferrimagnetism, and Composition Dependence.

ERIC Educational Resources Information Center

Hong, Y. S.; And Others

1980-01-01

Describes some contemporary concepts unique to the structure of advanced solids, i.e., their crystal distortions, domain structures, modulated structures, ferrimagnetism, and composition dependence. (Author/CS)

MEMS based ion beams for fusion

NASA Astrophysics Data System (ADS)

Persaud, A.; Seidl, P. A.; Ji, Q.; Waldron, W. L.; Schenkel, T.; Ardanuc, S.; Vinayakumar, K. B.; Schaffer, Z. A.; Lal, A.

2016-10-01

Micro-Electro-Mechanical Systems (MEMS) fabrication provides an exciting opportunity to shrink existing accelerator concepts to smaller sizes and to reduce cost by orders of magnitude. We revisit the concept of a Multiple Electrostatic Quadrupole Array Linear Accelerator (MEQALAC) and show how, with current technologies, the concept can be downsized from gap distances of several cm to distances in the sub-mm regime. The basic concept implements acceleration gaps using radio frequency (RF) fields and electrostatic quadrupoles (ESQ) on silicon wafers. First results from proof-of-concept experiments using printed circuit boards to realize the MEQALAC structures are presented. We show results from accelerating structures that were used in an array of nine (3x3) parallel beamlets with He ions at 15 keV. We will also present results from an ESQ focusing lattice using the same beamlet layout showing beam transport and matching. We also will discuss our progress in fabricating MEMS devices in silicon wafers for both the RF and ESQ structures and integration of necessary RF-circuits on-chip. The concept can be scaled up to thousands of beamlets providing high power beams at low cost and can be used to form and compress a plasma for the development of magnetized target fusion approaches. This work was supported by the Office of Science of the US Department of Energy through the ARPA-e ALPHA program under contracts DE-AC0205CH11231 (LBNL).

A Tangible Approach to Concept Mapping

NASA Astrophysics Data System (ADS)

Tanenbaum, Karen; Antle, Alissa N.

2009-05-01

The Tangible Concept Mapping project investigates using a tangible user interface to engage learners in concept map creation. This paper describes a prototype implementation of the system, presents some preliminary analysis of its ease of use and effectiveness, and discusses how elements of tangible interaction support concept mapping by helping users organize and structure their knowledge about a domain. The role of physical engagement and embodiment in supporting the mental activity of creating the concept map is explored as one of the benefits of a tangible approach to learning.

Development and Evaluation of Sensor Concepts for Ageless Aerospace Vehicles: Report 4 - Phase 1 Implementation of the Concept Demonstrator

NASA Technical Reports Server (NTRS)

Abbott, David; Batten, Adam; Carpenter, David; Dunlop, John; Edwards, Graeme; Farmer, Tony; Gaffney, Bruce; Hedley, Mark; Hoschke, Nigel; Isaacs, Peter;

The concept of hierarchy in general systems theory.

PubMed

Gasparski, W

1994-01-01

The paper reviews main ideas related to the concept of hierarchy as they are discussed in contemporary general systems theory. After presenting a dictionary definition of the concept, the author examines the intuitive idea of hierarchy quoting Mario Bunge's notion of level structure. Then relationship between two other concepts: a system and a hierarchy is characterised on the bases of Bowler's, Bunge's again, Klir's, and the author's studies. Finally, the paper is concluded that hierarchy is not an otological concept but epistemological one.

Analyzing structural changes in SNOMED CT's Bacterial infectious diseases using a visual semantic delta.

PubMed

Ochs, Christopher; Case, James T; Perl, Yehoshua

2017-03-01

Thousands of changes are applied to SNOMED CT's concepts during each release cycle. These changes are the result of efforts to improve or expand the coverage of health domains in the terminology. Understanding which concepts changed, how they changed, and the overall impact of a set of changes is important for editors and end users. Each SNOMED CT release comes with delta files, which identify all of the individual additions and removals of concepts and relationships. These files typically contain tens of thousands of individual entries, overwhelming users. They also do not identify the editorial processes that were applied to individual concepts and they do not capture the overall impact of a set of changes on a subhierarchy of concepts. In this paper we introduce a methodology and accompanying software tool called a SNOMED CT Visual Semantic Delta ("semantic delta" for short) to enable a comprehensive review of changes in SNOMED CT. The semantic delta displays a graphical list of editing operations that provides semantics and context to the additions and removals in the delta files. However, there may still be thousands of editing operations applied to a set of concepts. To address this issue, a semantic delta includes a visual summary of changes that affected sets of structurally and semantically similar concepts. The software tool for creating semantic deltas offers views of various granularities, allowing a user to control how much change information they view. In this tool a user can select a set of structurally and semantically similar concepts and review the editing operations that affected their modeling. The semantic delta methodology is demonstrated on SNOMED CT's Bacterial infectious disease subhierarchy, which has undergone a significant remodeling effort over the last two years. Copyright © 2017 Elsevier Inc. All rights reserved.

Urban e-Mobility - Challenges and potential solutions using the example of the "E3W" concept vehicle

NASA Astrophysics Data System (ADS)

Perterer, M.; Martin, P.; Lochner, H.

2014-05-01

Due to the increasing number of people in urban areas, there is a need for affordable individual transportation. Limited space in cities together with the need for a significant reduction of pollution will lead to new mobility concepts in the near future. The aim of these concepts is not replacing the car itself, but to supply an additional personal transportation solution with local zero emission. Therefore, electrical powered vehicle concepts may be used. Due to the limited energy density and high cost of current Li-ion batteries, a significant weight reduction of the vehicle could lead to acceptable range and cost. In order to develop an affordable urban concept, the requirements for this kind of vehicle also have to be adjusted in comparison to conventional cars. This concept, the so called "E3W", combines the advantages of a two-wheeler with those of a four-wheeler, resulting in a lightweight and compact vehicle. This concept accommodates space for two persons with luggage and guarantees a high level of safety including wind and weather protection. The overall measures of this vehicle are smaller than current compact cars and allow therefore better use in cities. In order to fulfill technical and commercial requirements, a load carrying, short fiber reinforced thermoplastic body structure is chosen, combining good weight specific mechanical properties and low production costs. This highly integrated body structure also provides the body cover all in one. Pultruded glass fiber reinforced plastic (GFRP) beams are used as the backbone for the vehicle by carrying the main loads, the front crash structure and the rear swingarm. Finally, two prototypes are built to investigate the driving behavior, proof the concept and the suitability for daily use.

Analyzing Structural Changes in SNOMED CT’s Bacterial Infectious Diseases Using a Visual Semantic Delta

PubMed Central

Ochs, Christopher; Case, James T.; Perl, Yehoshua

2017-01-01

Thousands of changes are applied to SNOMED CT’s concepts during each release cycle. These changes are the result of efforts to improve or expand the coverage of health domains in the terminology. Understanding which concepts changed, how they changed, and the overall impact of a set of changes is important for editors and end users. Each SNOMED CT release comes with delta files, which identify all of the individual additions and removals of concepts and relationships. These files typically contain tens of thousands of individual entries, overwhelming users. They also do not identify the editorial processes that were applied to individual concepts and they do not capture the overall impact of a set of changes on a subhierarchy of concepts. In this paper we introduce a methodology and accompanying software tool called a SNOMED CT Visual Semantic Delta (“semantic delta” for short) to enable a comprehensive review of changes in SNOMED CT. The semantic delta displays a graphical list of editing operations that provides semantics and context to the additions and removals in the delta files. However, there may still be thousands of editing operations applied to a set of concepts. To address this issue, a semantic delta includes a visual summary of changes that affected sets of structurally and semantically similar concepts. The software tool for creating semantic deltas offers views of various granularities, allowing a user to control how much change information they view. In this tool a user can select a set of structurally and semantically similar concepts and review the editing operations that affected their modeling. The semantic delta methodology is demonstrated on SNOMED CT’s Bacterial infectious disease subhierarchy, which has undergone a significant remodeling effort over the last two years. PMID:28215561

Advanced Technology Composite Fuselage - Repair and Damage Assessment Supporting Maintenance

NASA Technical Reports Server (NTRS)

Flynn, B. W.; Bodine, J. B.; Dopker, B.; Finn, S. R.; Griess, K. H.; Hanson, C. T.; Harris, C. G.; Nelson, K. M.; Walker, T. H.; Kennedy, T. C.;

Abstraction of complex concepts with a refined partial-area taxonomy of SNOMED

PubMed Central

Wang, Yue; Halper, Michael; Wei, Duo; Perl, Yehoshua; Geller, James

2012-01-01

An algorithmically-derived abstraction network, called the partial-area taxonomy, for a SNOMED hierarchy has led to the identification of concepts considered complex. The designation “complex” is arrived at automatically on the basis of structural analyses of overlap among the constituent concept groups of the partial-area taxonomy. Such complex concepts, called overlapping concepts, constitute a tangled portion of a hierarchy and can be obstacles to users trying to gain an understanding of the hierarchy’s content. A new methodology for partitioning the entire collection of overlapping concepts into singly-rooted groups, that are more manageable to work with and comprehend, is presented. Different kinds of overlapping concepts with varying degrees of complexity are identified. This leads to an abstract model of the overlapping concepts called the disjoint partial-area taxonomy, which serves as a vehicle for enhanced, high-level display. The methodology is demonstrated with an application to SNOMED’s Specimen hierarchy. Overall, the resulting disjoint partial-area taxonomy offers a refined view of the hierarchy’s structural organization and conceptual content that can aid users, such as maintenance personnel, working with SNOMED. The utility of the disjoint partial-area taxonomy as the basis for a SNOMED auditing regimen is presented in a companion paper. PMID:21878396

A Concept Analysis of Patient Participation in Intermediate Care.

PubMed

Kvæl, Linda Aimée Hartford; Debesay, Jonas; Langaas, Anne; Bye, Asta; Bergland, Astrid

2018-03-05

Although the concept of patient participation has been discussed for a number of years, there is still no clear definition of what constitutes the multidimensional concept, and the application of the concept in an intermediate care (IC) context lacks clarity. Therefore this paper seeks to identify and explore the attributes of the concept, to elaborate ways of understanding the concept of patient participation for geriatric patients in the context of IC. Walker and Avant's model of Concept analysis [1] based on a literature review. Patient participation in the context of IC can be defined as a dynamic process emphasizing the person as a whole, focusing on the establishment of multiple alliances that facilitate individualized information and knowledge exchange, and ensuring a reciprocal engagement in activities within flexible and interactive/dynamic organizational structures. Patient participation in IC means involving patients and their relatives in holistic interdisciplinary collaborative decision-making. The results highlight the complexity of patient participation and contribute to a greater understanding of the influence of organizational structure and management. The present study may provide a practical framework for researchers, policy makers and health professionals to facilitate patient participation in IC services. Copyright © 2018 Elsevier B.V. All rights reserved.

The Impact of Using Model of Marzano Gain Students the Ability to Configure an Integrated Conceptual Structure in Islamic Concepts

ERIC Educational Resources Information Center

Alkhateeb, Omar

2015-01-01

The study aimed that the impact of using model of Marzano gain students the ability to configure an integrated conceptual structure in Islamic concepts the Sample included studious (120) student students the first year where of college of the educational sciences study in, two branches be organized in their choice was complete random among seven…

Structural Considerations of a 20MW Multi-Rotor Wind Energy System

NASA Astrophysics Data System (ADS)

Jamieson, P.; Branney, M.

2014-12-01

The drive to upscale offshore wind turbines relates especially to possiblereductions in O&M and electrical interconnection costs per MW of installed capacity.Even with best current technologies, designs with rated capacity above about 3 MW are less cost effective exfactory per rated MW(turbine system costs) than smaller machines.Very large offshore wind turbines are thereforejustifiedprimarily by overall offshore project economics. Furthermore, continuing progress in materials and structures has been essential to avoid severe penalties in the power/mass ratio of large multi-MW machines.The multi-rotor concept employs many small rotors to maximise energy capture area withminimum systemvolume. Previous work has indicated that this can enablea very large reduction in the total weight and cost of rotors and drive trains compared to an equivalent large single rotor system.Thus the multi rotor concept may enable rated capacities of 20 MW or more at a single maintenancesite. Establishing the cost benefit of a multi rotor system requires examination of solutions for the support structure and yawing, ensuring aerodynamic losses from rotor interaction are not significant and that overall logistics, with much increased part count (more reliable components) and less consequence of single failuresare favourable. This paper addresses the viability of a support structure in respect of structural concept and likely weight as one necessary step in exploring the potential of the multi rotor concept.

The collaboration of general practitioners and nurses in primary care: a comparative analysis of concepts and practices in Slovenia and Spain.

PubMed

Hämel, Kerstin; Vössing, Carina

2017-09-01

Aim A comparative analysis of concepts and practices of GP-nurse collaborations in primary health centres in Slovenia and Spain. Cross-professional collaboration is considered a key element for providing high-quality comprehensive care by combining the expertise of various professions. In many countries, nurses are also being given new and more extensive responsibilities. Implemented concepts of collaborative care need to be analysed within the context of care concepts, organisational structures, and effective collaboration. Background review of primary care concepts (literature analysis, expert interviews), and evaluation of collaboration in 'best practice' health centres in certain regions of Slovenia and Spain. Qualitative content analysis of expert interviews, presentations, observations, and group discussions with professionals and health centre managers. Findings In Slovenian health centres, the collaboration between GPs and nurses has been strongly shaped by their organisation in separate care units and predominantly case-oriented functions. Conventional power structures between professions hinder effective collaboration. The introduction of a new cross-professional primary care concept has integrated advanced practice nurses into general practice. Conventional hierarchies still exist, but a shared vision of preventive care is gradually strengthening attitudes towards team-oriented care. Formal regulations or incentives for teamwork have yet to be implemented. In Spain, health centres were established along with a team-based care concept that encompasses close physician-nurse collaboration and an autonomous role for nurses in the care process. Nurses collaborate with GPs on more equal terms with conflicts centring on professional disagreements. Team development structures and financial incentives for team achievements have been implemented, encouraging teams to generate their own strategies to improve teamwork. Clearly defined structures, shared visions of care and team development are important for implementing and maintaining a good collaboration. Central prerequisites are advanced nursing education and greater acceptance of advanced nursing practice.

A knowledge-driven approach to biomedical document conceptualization.

PubMed

Zheng, Hai-Tao; Borchert, Charles; Jiang, Yong

2010-06-01

Biomedical document conceptualization is the process of clustering biomedical documents based on ontology-represented domain knowledge. The result of this process is the representation of the biomedical documents by a set of key concepts and their relationships. Most of clustering methods cluster documents based on invariant domain knowledge. The objective of this work is to develop an effective method to cluster biomedical documents based on various user-specified ontologies, so that users can exploit the concept structures of documents more effectively. We develop a flexible framework to allow users to specify the knowledge bases, in the form of ontologies. Based on the user-specified ontologies, we develop a key concept induction algorithm, which uses latent semantic analysis to identify key concepts and cluster documents. A corpus-related ontology generation algorithm is developed to generate the concept structures of documents. Based on two biomedical datasets, we evaluate the proposed method and five other clustering algorithms. The clustering results of the proposed method outperform the five other algorithms, in terms of key concept identification. With respect to the first biomedical dataset, our method has the F-measure values 0.7294 and 0.5294 based on the MeSH ontology and gene ontology (GO), respectively. With respect to the second biomedical dataset, our method has the F-measure values 0.6751 and 0.6746 based on the MeSH ontology and GO, respectively. Both results outperforms the five other algorithms in terms of F-measure. Based on the MeSH ontology and GO, the generated corpus-related ontologies show informative conceptual structures. The proposed method enables users to specify the domain knowledge to exploit the conceptual structures of biomedical document collections. In addition, the proposed method is able to extract the key concepts and cluster the documents with a relatively high precision. Copyright 2010 Elsevier B.V. All rights reserved.

Central Distractors in Force Concept Inventory Data

ERIC Educational Resources Information Center

Scott, Terry F.; Schumayer, Dániel

2018-01-01

The Force Concept Inventory was designed to poll the Newtonian conception of force. While there are many in-depth studies analyzing response data that look at the structure of the correct answers, we believe that the incorrect answers also carry revealing information about the students' worldview. The inventory was originally designed so that the…

Efficient concepts for large erectable space structures

NASA Technical Reports Server (NTRS)

Card, M. F.; Bush, H. G.; Heard, W. L., Jr.; Mikulas, M. M., Jr.

1978-01-01

The status of Langley Research Center development of the nestable column concept is reviewed including results of member and truss component tests, and planned assembly studies. In addition, more recent studies of alternative member concepts are presented. Preliminary results on relative efficiency of several types of truss-type columns are compared and future test plans discussed.

A Structural Analysis of the Determinants of Job Satisfactions in On-Going Organizations.

ERIC Educational Resources Information Center

Vaughn, William J.; Dunn, J. D.

Organizational effectiveness is composed of two concepts: (1) job satisfactions and (2) employee performance. In this paper the concept of job satisfactions is delimited to include five principal areas, viz., work, pay, promotion, people, and supervision. Employee performance is the reciprocal concept. This paper is directed toward the job…

IRM Concepts: Building Blocks for the 1990s.

ERIC Educational Resources Information Center

Owen, Darrell E.

1989-01-01

Presents a conceptual overview of information resources management (IRM) by synthesizing concepts put forward during the 1980s and charts opportunities to move these concepts into practice. It is argued that the reorganization required by IRM is justified by better use of resources, better decision making, and an improved corporate structure. (21…

Astronomy in Early Childhood Education: A Concept-Based Approach

ERIC Educational Resources Information Center

Ampartzaki, Maria; Kalogiannakis, Michail

2016-01-01

In an attempt to understand the natural world's phenomena, young children form their perceptions of different aspects of the macrocosm, which they contrast with new scientific concepts. This process calls for an early intervention that will provide the stimuli and the tools for the development of new concepts, ideas, and cognitive structures. The…

Prospective Mathematics Teachers' Understanding of the Base Concept

ERIC Educational Resources Information Center

Horzum, Tugba; Ertekin, Erhan

2018-01-01

The purpose of this study is to analyze what kind of conceptions prospective mathematics teachers (PMTs) have about the base concept (BC). One-hundred and thirty-nine PMTs participated in the study. In this qualitative research, data were obtained through open-ended questions, the semi-structured interviews and pictures of geometric figures drawn…

Validation and Structural Analysis of the Kinematics Concept Test

ERIC Educational Resources Information Center

Lichtenberger, A.; Wagner, C.; Hofer, S. I.; Stem, E.; Vaterlaus, A.

2017-01-01

The kinematics concept test (KCT) is a multiple-choice test designed to evaluate students' conceptual understanding of kinematics at the high school level. The test comprises 49 multiple-choice items about velocity and acceleration, which are based on seven kinematic concepts and which make use of three different representations. In the first part…

CURRENT VFARS ONGOING RESEARCH AND WHAT NEEDS TO BE DONE TO EVALUATE THE VFARS CONCEPT AND DETERMINE ITS FEASIBILITY

EPA Science Inventory

The VFARs concept predicts that pathogens can be identified using structural similarities among virulence genes from diverse species. This concept is of interest to the EPA for several reasons: the Agency's need to discriminate between virulent and avirulent isolates of pathogen...

Joined up Thinking? Evaluating the Use of Concept-Mapping to Develop Complex System Learning

ERIC Educational Resources Information Center

Stewart, Martyn

2012-01-01

In the physical and natural sciences, the complexity of natural systems and their interactions is becoming better understood. With increased emphasis on learning about complex systems, students will be encountering concepts that are dynamic, ill-structured and interconnected. Concept-mapping is a method considered particularly valuable for…

The Conservation of Energy Concept in Ninth Grade General Science, Final Report.

ERIC Educational Resources Information Center

Shockley, William; And Others

Discussed is an instructional approach, "concept-distillation," which involves experiences, games, and puzzles that have the "distilled essence" of the basic concepts of the physical sciences. This approach is designed to impart a vivid and dramatic meaning and structure of the sciences for transfer in scientific thinking. The…

Turkish Prospective Chemistry Teachers' Alternative Conceptions about Acids and Bases

ERIC Educational Resources Information Center

Boz, Yezdan

2009-01-01

The purpose of this study was to obtain prospective chemistry teachers' conceptions about acids and bases concepts. Thirty-eight prospective chemistry teachers were the participants. Data were collected by means of an open-ended questionnaire and semi-structured interviews. Analysis of data indicated that most prospective teachers did not have…

Reciprocal Relationships between Math Self-Concept and Math Anxiety

ERIC Educational Resources Information Center

Ahmed, Wondimu; Minnaert, Alexander; Kuyper, Hans; van der Werf, Greetje

2012-01-01

The present study examined the reciprocal relationships between self-concept and anxiety in mathematics. A sample of 495 grade 7 students (51% girls) completed self-report measures assessing self-concept and anxiety three times in a school year. Structural equation modeling was used to test a cross-lagged panel model of reciprocal effects between…

Queensland Teachers' Conceptions of Assessment: The Impact of Policy Priorities on Teacher Attitudes

ERIC Educational Resources Information Center

Brown, Gavin T. L.; Lake, Robert; Matters, Gabrielle

2011-01-01

The conceptions Queensland teachers have about assessment purposes were surveyed in 2003 with an abridged version of the Teacher Conceptions of Assessment Inventory. Multi-group analysis found that a model with four factors, somewhat different in structure to previous studies, was statistically different between Queensland primary and (lower)…

MCA-NMF: Multimodal Concept Acquisition with Non-Negative Matrix Factorization

PubMed Central

Mangin, Olivier; Filliat, David; ten Bosch, Louis; Oudeyer, Pierre-Yves

2015-01-01

In this paper we introduce MCA-NMF, a computational model of the acquisition of multimodal concepts by an agent grounded in its environment. More precisely our model finds patterns in multimodal sensor input that characterize associations across modalities (speech utterances, images and motion). We propose this computational model as an answer to the question of how some class of concepts can be learnt. In addition, the model provides a way of defining such a class of plausibly learnable concepts. We detail why the multimodal nature of perception is essential to reduce the ambiguity of learnt concepts as well as to communicate about them through speech. We then present a set of experiments that demonstrate the learning of such concepts from real non-symbolic data consisting of speech sounds, images, and motions. Finally we consider structure in perceptual signals and demonstrate that a detailed knowledge of this structure, named compositional understanding can emerge from, instead of being a prerequisite of, global understanding. An open-source implementation of the MCA-NMF learner as well as scripts and associated experimental data to reproduce the experiments are publicly available. PMID:26489021

Pharmacology Goes Concept-Based: Course Design, Implementation, and Evaluation.

PubMed

Lanz, Amelia; Davis, Rebecca G

Although concept-based curricula are frequently discussed in the nursing education literature, little information exists to guide the development of a concept-based pharmacology course. Traditionally, nursing pharmacology courses are taught with an emphasis on drug class where a prototype drug serves as an exemplar. When transitioning pharmacology to a concept-based course, special considerations are in order. How can educators successfully integrate essential pharmacological content into a curriculum structured around nursing concepts? This article presents one approach to the design and implementation of a concept-based undergraduate pharmacology course. Planning methods, supportive teaching strategies, and course evaluation procedures are discussed.

Students' understanding of primary and secondary protein structure: drawing secondary protein structure reveals student understanding better than simple recognition of structures.

PubMed

Harle, Marissa; Towns, Marcy H

2013-01-01

The interdisciplinary nature of biochemistry courses requires students to use both chemistry and biology knowledge to understand biochemical concepts. Research that has focused on external representations in biochemistry has uncovered student difficulties in comprehending and interpreting external representations in addition to a fragmented understanding of fundamental biochemistry concepts. This project focuses on students' understanding of primary and secondary protein structure and drawings (representations) of hydrogen-bonding in alpha helices and beta sheets. Analysis demonstrated that students can recognize and identify primary protein structure concepts when given a polypeptide. However, when asked to draw alpha helices and beta sheets and explain the role of hydrogen bonding their drawings students exhibited a fragmented understanding that lacked coherence. Faculty are encouraged to have students draw molecular level representations to make their mental models more explicit, complete, and coherent. This is in contrast to recognition and identification tasks, which do not adequately probe mental models and molecular level understanding. © 2013 by The International Union of Biochemistry and Molecular Biology.

A Novel SMA-based Concept for Airfoil Structural Morphing

NASA Astrophysics Data System (ADS)

Barbarino, S.; Pecora, R.; Lecce, L.; Concilio, A.; Ameduri, S.; Calvi, E.

2009-08-01

The adaptive structures concept is of great interest in the aerospace field because of the several benefits which can be accomplished in the fields including noise reduction, load alleviation, weight reduction, etc., at a level in which they can be considered as compulsory in the design of future aircraft. Improvements in terms of the aerodynamic efficiency, aeroelastic behavior, stability, and manoeuvrability performance have already been proved through many international studies in the past. In the family of the Smart Materials, Shape Memory Alloys (SMA) seem to be a suitable solution for many static applications. Their high structural integrability in conjunction with actuation capabilities and a favorable performance per weight ratio, allows the development of original architectures. In this study, a morphing wing trailing edge concept is presented; morphing ability was introduced with the aim of replacing a conventional flap device. A compliant rib structure was designed, based on SMA actuators exhibiting structural potential (bearing external aerodynamic loads). Numerical results, achieved through a FE approach, are presented in terms of trailing edge induced displacement and morphed shape.

Robotic influence in the conceptual design of mechanical systems in space and vice versa - A survey

NASA Technical Reports Server (NTRS)

Sanger, George F.

1988-01-01

A survey of methods using robotic devices to construct structural elements in space is presented. Two approaches to robotic construction are considered: one in which the structural elements are designed using conventional aerospace techniques which tend to constrain the function aspects of robotics and one in which the structural elements are designed from the conceptual stage with built-in robotic features. Examples are presented of structural building concepts using robotics, including the construction of the SP-100 nuclear reactor power system, a multimirror large aperture IR space telescope concept, retrieval and repair in space, and the Flight Telerobotic Servicer.

Concept of a self-associated multimer structure of coal

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

Gagarin, S.G.; Krichko, A.A.

1984-01-01

The paper examines the role of donor-acceptor reaction in the binding of the individual components forming the structure of the organic coal mass, and analyses the manifestations of this reaction during liquefaction. The authors put forward the concept of self-associated polymers in the coal structure, in accordance with which the organic coal mass has spatial and energetic distribution of the donor and acceptor sectors of structure. It is the specific reaction between these which produces the necessary stability to the polymer system under normal conditions. The authors propose a mechanism for the action of solvents and various additives in themore » liquefaction of coal.« less

Design and implementation of robust decentralized control laws for the ACES structure at Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Collins, Emmanuel G., Jr.; Phillips, Douglas J.; Hyland, David C.

1990-01-01

Many large space system concepts will require active vibration control to satisfy critical performance requirements such as line-of-sight accuracy. In order for these concepts to become operational it is imperative that the benefits of active vibration control be practically demonstrated in ground based experiments. The results of the experiment successfully demonstrate active vibration control for a flexible structure. The testbed is the Active Control Technique Evaluation for Spacecraft (ACES) structure at NASA Marshall Space Flight Center. The ACES structure is dynamically traceable to future space systems and especially allows the study of line-of-sight control issues.

Astronaut Ross Approaches Assembly Concept for Construction of Erectable Space Structure (ACCESS)

NASA Technical Reports Server (NTRS)

1999-01-01

The crew assigned to the STS-61B mission included Bryan D. O'Conner, pilot; Brewster H. Shaw, commander; Charles D. Walker, payload specialist; mission specialists Jerry L. Ross, Mary L. Cleave, and Sherwood C. Spring; and Rodolpho Neri Vela, payload specialist. Launched aboard the Space Shuttle Atlantis November 28, 1985 at 7:29:00 pm (EST), the STS-61B mission's primary payload included three communications satellites: MORELOS-B (Mexico); AUSSAT-2 (Australia); and SATCOM KU-2 (RCA Americom). Two experiments were conducted to test assembling erectable structures in space: EASE (Experimental Assembly of Structures in Extravehicular Activity), and ACCESS (Assembly Concept for Construction of Erectable Space Structure). In a joint venture between NASA/Langley Research Center in Hampton, Virginia, and the Marshall Space Flight Center (MSFC), EASE and ACCESS were developed and demonstrated at MSFC's Neutral Buoyancy Simulator (NBS). In this STS-61B onboard photo, astronaut Ross, perched on the Manipulator Foot Restraint (MFR) approaches the erected ACCESS. The primary objective of these experiments was to test the structural assembly concepts for suitability as the framework for larger space structures and to identify ways to improve the productivity of space construction.

STS-61B Astronaut Ross Works on Assembly Concept for Construction of Erectable Space Structure

NASA Technical Reports Server (NTRS)

1985-01-01

The crew assigned to the STS-61B mission included Bryan D. O'Conner, pilot; Brewster H. Shaw, commander; Charles D. Walker, payload specialist; mission specialists Jerry L. Ross, Mary L. Cleave, and Sherwood C. Spring; and Rodolpho Neri Vela, payload specialist. Launched aboard the Space Shuttle Atlantis November 28, 1985 at 7:29:00 pm (EST), the STS-61B mission's primary payload included three communications satellites: MORELOS-B (Mexico); AUSSAT-2 (Australia); and SATCOM KU-2 (RCA Americom). Two experiments were conducted to test assembling erectable structures in space: EASE (Experimental Assembly of Structures in Extravehicular Activity), and ACCESS (Assembly Concept for Construction of Erectable Space Structure). In a joint venture between NASA/Langley Research Center in Hampton, Virginia and the Marshall Space Flight Center (MSFC), EASE and ACCESS were developed and demonstrated at MSFC's Neutral Buoyancy Simulator (NBS). In this STS-61B onboard photo astronaut Ross, located on the Manipulator Foot Restraint (MFR) over the cargo bay, erects ACCESS. The primary objective of this experiment was to test the structural assembly concepts for suitability as the framework for larger space structures and to identify ways to improve the productivity of space construction.

Ross Works on the Assembly Concept for Construction of Erectable Space Structure (ACCESS) During

NASA Technical Reports Server (NTRS)

1985-01-01

The crew assigned to the STS-61B mission included Bryan D. O'Conner, pilot; Brewster H. Shaw, commander; Charles D. Walker, payload specialist; mission specialists Jerry L. Ross, Mary L. Cleave, and Sherwood C. Spring; and Rodolpho Neri Vela, payload specialist. Launched aboard the Space Shuttle Atlantis November 28, 1985 at 7:29:00 pm (EST), the STS-61B mission's primary payload included three communications satellites: MORELOS-B (Mexico); AUSSAT-2 (Australia); and SATCOM KU-2 (RCA Americom). Two experiments were conducted to test assembling erectable structures in space: EASE (Experimental Assembly of Structures in Extravehicular Activity), and ACCESS (Assembly Concept for Construction of Erectable Space Structure). In a joint venture between NASA/Langley Research Center in Hampton, Virginia, and the Marshall Space Flight Center (MSFC), EASE and ACCESS were developed and demonstrated at MSFC's Neutral Buoyancy Simulator (NBS). In this STS-61B onboard photo, astronaut Ross works on ACCESS high above the orbiter. The primary objective of these experiments was to test the structural assembly concepts for suitability as the framework for larger space structures and to identify ways to improve the productivity of space construction.

Evaluation of a large capacity heat pump concept for active cooling of hypersonic aircraft structure

NASA Technical Reports Server (NTRS)

Pagel, L. L.; Herring, R. L.

1978-01-01

Results of engineering analyses assessing the conceptual feasibility of a large capacity heat pump for enhancing active cooling of hypersonic aircraft structure are presented. A unique heat pump arrangement which permits cooling the structure of a Mach 6 transport to aluminum temperatures without the aid of thermal shielding is described. The selected concept is compatible with the use of conventional refrigerants, with Freon R-11 selected as the preferred refrigerant. Condenser temperatures were limited to levels compatible with the use of conventional refrigerants by incorporating a unique multipass condenser design, which extracts mechanical energy from the hydrogen fuel, prior to each subsequent pass through the condenser. Results show that it is technically feasible to use a large capacity heat pump in lieu of external shielding. Additional analyses are required to optimally apply this concept.

Development of Rene 41 honeycomb structure as an integral cryogenic tankage/fuselage concept for future space transportation systems

NASA Technical Reports Server (NTRS)

Shideler, J. L.; Swegle, A. R.; Fields, R. A.

1982-01-01

The status of the structural development of an integral cryogenic-tankage/hot-fuselage concept for future space transportation systems is reviewed. The concept comprises a honeycomb sandwich structure that serves the combined functions of containing the cryogenic fuel, supporting the vehicle loads, and protecting the spacecraft from entry heating. The inner face sheet is exposed to cryogenic temperature of -423 F during boost; the outer face sheet, which is slotted to reduce thermal stress, is exposed to a maximum temperature of 1400 F during a high-altitude gliding entry. Attention is given to the development of a fabrication process for a Rene 41 honeycomb sandwich panel with a core density of less than 1 percent that is consistent with desirable heat treatment processes for high strength.

Development of Rene' 41 honeycomb structure as an integral cryogenic tankage/fuselage concept for future space transportation systems

NASA Technical Reports Server (NTRS)

Shideler, J. J.; Swegle, A. R.; Fields, R. A.

1982-01-01

The status of the structural development of an integral cryogenic-tankage/hot-fuselage concept for future space transportation systems (STS) is discussed. The concept consists of a honeycomb sandwich structure which serves the combined functions of containment of cryogenic fuel, support of vehicle loads, and thermal protection from an entry heating environment. The inner face sheet is exposed to a cryogenic (LH2) temperature of -423 F during boost; and the outer face sheet, which is slotted to reduce thermal stress, is exposed to a maximum temperature of 1400 F during a high altitude, gliding entry. A fabrication process for a Rene' 41 honeycomb sandwich panel with a core density less than 1 percent was developed which is consistent with desirable heat treatment processes for high strength.

Ecotechnology: basis of a new immission concept in water pollution control.

PubMed

Benndorf, J

2005-01-01

Beyond the traditional load reduction also an ecosystem-internal mechanism can be used to minimise the effects of water pollution. The control of the internal mechanisms is achieved through the optimisation of the ecosystem structure. This ecotechnology principle is based on the idea to reduce as much as possible the gap between the current (suboptimal) structural status and the optimum structure by intentional manipulations. The spectrum of such manipulations is very broad. A few examples are demonstrated. They comprise physical (e.g. stream morphology), chemical (e.g. enhancing the redox potential at the sediment-water interface) and biological (e.g. enhancing stocks of predatory fishes) control measures. It can be supposed that a new immission concept including the ecotechnology principle could be much more adequate to the demand of modern water pollution control than the traditional emission and imission concepts.

Advanced leading edge thermal-structure concept. Direct bond reusable surface insulation to a composite structure

NASA Technical Reports Server (NTRS)

Riccitiello, S. R.; Figueroa, H.; Coe, C. F.; Kuo, C. P.

1984-01-01

An advanced leading-edge concept was analyzed using the space shuttle leading edge system as a reference model. The comparison indicates that a direct-bond system utilizing a high temperature (2700 F) fibrous refractory composite insulation tile bonded to a high temperature (PI/graphite) composite structure can result in a weight savings of up to 800 lb. The concern that tile damage or loss during ascent would result in adverse entry aerodynamics if a leading edge tile system were used is addressed. It was found from experiment that missing tiles (as many as 22) on the leading edge would not significantly affect the basic force-and-moment aerodynamic coefficients. Additionally, this concept affords a degree of redundancy to a thermal protection system in that the base structure (being a composite material) ablates and neither melts nor burns through when subjected to entry heating in the event tiles are actually lost or damaged during ascent.

Tailoring the Employment of Offshore Wind Turbine Support Structure Load Mitigation Controllers

NASA Astrophysics Data System (ADS)

Shrestha, Binita; Kühn, Martin

2016-09-01

The currently available control concepts to mitigate aerodynamic and hydrodynamic induced support structure loads reduce either fore-aft or side-to-side damage under certain operational conditions. The load reduction is achieved together with an increase in loads in other components of the turbine e.g. pitch actuators or drive train, increasing the risk of unscheduled maintenance. The main objective of this paper is to demonstrate a methodology for reduction of support structure damage equivalent loads (DEL) in fore-aft and side-to-side directions using already available control concepts. A multi-objective optimization problem is formulated to minimize the DELs, while limiting the collateral effects of the control algorithms for load reduction. The optimization gives trigger values of sea state condition for the activation or deactivation of certain control concepts. As a result, by accepting the consumption of a small fraction of the load reserve in the design load envelope of other turbine components, a considerable reduction of the support structure loads is facilitated.

Low frequency cabin noise reduction based on the intrinsic structural tuning concept: The theory and the experimental results, phase 2. [jet aircraft noise

NASA Technical Reports Server (NTRS)

Sengupta, G.

1978-01-01

Low frequency cabin noise and sonically induced stresses in an aircraft fuselage may be reduced by intrinsic tuning of the various structural members such as the skin, stringers, and frames and then applying damping treatments on these members. The concept is also useful in identifying the key structural resonance mechanisms controlling the fuselage response to broadband random excitation and in developing suitable damping treatments for reducing the structural response in various frequency ranges. The mathematical proof of the concept and the results of some laboratory and field tests on a group of skin-stringer panels are described. In the so-called stiffness-controlled region, the noise transmission may actually be controlled by stiffener resonances, depending upon the relationship between the natural frequencies of the skin bay and the stiffeners. Therefore, cabin noise in the stiffness-controlled region may be effectively reduced by applying damping treatments on the stiffeners.

Structural Framework for Flight: NASA's Role in Development of Advanced Composite Materials for Aircraft and Space Structures

NASA Technical Reports Server (NTRS)

Tenney, Darrel R.; Davis, John G., Jr.; Johnston, Norman J.; Pipes, R. Byron; McGuire, Jack F.

2011-01-01

This serves as a source of collated information on Composite Research over the past four decades at NASA Langley Research Center, and is a key reference for readers wishing to grasp the underlying principles and challenges associated with developing and applying advanced composite materials to new aerospace vehicle concepts. Second, it identifies the major obstacles encountered in developing and applying composites on advanced flight vehicles, as well as lessons learned in overcoming these obstacles. Third, it points out current barriers and challenges to further application of composites on future vehicles. This is extremely valuable for steering research in the future, when new breakthroughs in materials or processing science may eliminate/minimize some of the barriers that have traditionally blocked the expanded application of composite to new structural or revolutionary vehicle concepts. Finally, a review of past work and identification of future challenges will hopefully inspire new research opportunities and development of revolutionary materials and structural concepts to revolutionize future flight vehicles.

Next Generation Car — Example of Function Integration at the Light Urban Vehicle (LUV) Vehicle Concept

NASA Astrophysics Data System (ADS)

Kopp, G.; Brückmann, S.; Kriescher, M.; Friedrich, H. E.

In times of climate change vehicle emissions have to be reduced clearly. One possibility is to reduce the mass of the body in white using lightweight sandwich structures. The department `Lightweight and Hybrid Design Methods' of the Institute of Vehicle Concepts develops a vehicle body structure by using sandwiches with aluminum top layers and polyurethane foam as core material. For that the foam and the sandwiches were investigated under different load cases, e.g. pressure loading and in-plane tests. In tests with components the high potential of the sandwich materials were shown. On the dynamic component test facility of the institute, vehicle front structures were tested successfully. The results of all investigations regarding sandwich materials, integration of functions (e.g. crash, thermal) in vehicle structures and the concept LUV are developed under the research program of Next Generation Car of the DLR. We will show the development and results of the LUV.

Sensitivity method for integrated structure/active control law design

NASA Technical Reports Server (NTRS)

Gilbert, Michael G.

1987-01-01

The development is described of an integrated structure/active control law design methodology for aeroelastic aircraft applications. A short motivating introduction to aeroservoelasticity is given along with the need for integrated structures/controls design algorithms. Three alternative approaches to development of an integrated design method are briefly discussed with regards to complexity, coordination and tradeoff strategies, and the nature of the resulting solutions. This leads to the formulation of the proposed approach which is based on the concepts of sensitivity of optimum solutions and multi-level decompositions. The concept of sensitivity of optimum is explained in more detail and compared with traditional sensitivity concepts of classical control theory. The analytical sensitivity expressions for the solution of the linear, quadratic cost, Gaussian (LQG) control problem are summarized in terms of the linear regulator solution and the Kalman Filter solution. Numerical results for a state space aeroelastic model of the DAST ARW-II vehicle are given, showing the changes in aircraft responses to variations of a structural parameter, in this case first wing bending natural frequency.

Classification-based reasoning

NASA Technical Reports Server (NTRS)

Gomez, Fernando; Segami, Carlos

1991-01-01

A representation formalism for N-ary relations, quantification, and definition of concepts is described. Three types of conditions are associated with the concepts: (1) necessary and sufficient properties, (2) contingent properties, and (3) necessary properties. Also explained is how complex chains of inferences can be accomplished by representing existentially quantified sentences, and concepts denoted by restrictive relative clauses as classification hierarchies. The representation structures that make possible the inferences are explained first, followed by the reasoning algorithms that draw the inferences from the knowledge structures. All the ideas explained have been implemented and are part of the information retrieval component of a program called Snowy. An appendix contains a brief session with the program.

Basic concepts for the design of high-efficiency single-junction and multibandgap solar cells

NASA Technical Reports Server (NTRS)

Fan, J. C. C.

1985-01-01

Concepts for obtaining practical solar-cell modules with one-sun efficiencies up to 30 percent at air mass 1 are now well understood. Such high-efficiency modules utilize multibandgap structures. To achieve module efficiencies significantly above 30 percent, it is necessary to employ different concepts such as spectral compression and broad-band detection. A detailed description of concepts for the design of high-efficiency multibandgap solar cells is given.

Concept mapping as an approach for expert-guided model building: The example of health literacy.

PubMed

Soellner, Renate; Lenartz, Norbert; Rudinger, Georg

2017-02-01

Concept mapping served as the starting point for the aim of capturing the comprehensive structure of the construct of 'health literacy.' Ideas about health literacy were generated by 99 experts and resulted in 105 statements that were subsequently organized by 27 experts in an unstructured card sorting. Multidimensional scaling was applied to the sorting data and a two and three-dimensional solution was computed. The three dimensional solution was used in subsequent cluster analysis and resulted in a concept map of nine "clusters": (1) self-regulation, (2) self-perception, (3) proactive approach to health, (4) basic literacy and numeracy skills, (5) information appraisal, (6) information search, (7) health care system knowledge and acting, (8) communication and cooperation, and (9) beneficial personality traits. Subsequently, this concept map served as a starting point for developing a "qualitative" structural model of health literacy and a questionnaire for the measurement of health literacy. On the basis of questionnaire data, a "quantitative" structural model was created by first applying exploratory factor analyses (EFA) and then cross-validating the model with confirmatory factor analyses (CFA). Concept mapping proved to be a highly valuable tool for the process of model building up to translational research in the "real world". Copyright © 2016 Elsevier Ltd. All rights reserved.

Testing of SMA-enabled Active Chevron Prototypes under Representative Flow Conditions

NASA Technical Reports Server (NTRS)

Turner, Travis L.; Cabell,Randolph H.; Cano, Roberto J.; Silcox, Richard J.

2008-01-01

Control of jet noise continues to be an important research topic. Exhaust-nozzle chevrons have been shown to reduce jet noise, but parametric effects are not well understood. Additionally, thrust loss due to chevrons at cruise suggests significant benefit from active chevrons. The focus of this study is development of an active chevron concept for the primary purpose of parametric studies for jet noise reduction in the laboratory and secondarily for technology development to leverage for full scale systems. The active chevron concept employed in this work consists of a laminated composite structure with embedded shape memory alloy (SMA) actuators, termed a SMA hybrid composite (SMAHC). SMA actuators are embedded on one side of the neutral axis of the structure such that thermal excitation, via joule heating, generates a moment and deflects the structure. The performance of two active chevron concepts is demonstrated in the presence of representative flow conditions. One of the concepts is shown to possess significant advantages for the proposed application and is selected for further development. Fabrication and design changes are described and shown to produce a chevron prototype that meets the performance objectives.

Structural concepts for large solar concentrators

NASA Technical Reports Server (NTRS)

Hedgepeth, John M.; Miller, Richard K.

1987-01-01

The Sunflower large solar concentrator, developed in the early 1970's, is a salient example of a high-efficiency concentrator. The newly emphasized needs for solar dynamic power on the Space Station and for large, lightweight thermal sources are outlined. Existing concepts for high efficiency reflector surfaces are examined with attention to accuracy needs for concentration rates of 1000 to 3000. Concepts using stiff reflector panels are deemed most likely to exhibit the long-term consistent accuracy necessary for low-orbit operation, particularly for the higher concentration ratios. Quantitative results are shown of the effects of surface errors for various concentration and focal-length diameter ratios. Cost effectiveness is discussed. Principal sources of high cost include the need for various dished panels for paraboloidal reflectors and the expense of ground testing and adjustment. A new configuration is presented addressing both problems, i.e., a deployable Pactruss backup structure with identical panels installed on the structure after deployment in space. Analytical results show that with reasonable pointing errors, this new concept is capable of concentration ratios greater than 2000.

A method for exploring implicit concept relatedness in biomedical knowledge network.

PubMed

Bai, Tian; Gong, Leiguang; Wang, Ye; Wang, Yan; Kulikowski, Casimir A; Huang, Lan

2016-07-19

Biomedical information and knowledge, structural and non-structural, stored in different repositories can be semantically connected to form a hybrid knowledge network. How to compute relatedness between concepts and discover valuable but implicit information or knowledge from it effectively and efficiently is of paramount importance for precision medicine, and a major challenge facing the biomedical research community. In this study, a hybrid biomedical knowledge network is constructed by linking concepts across multiple biomedical ontologies as well as non-structural biomedical knowledge sources. To discover implicit relatedness between concepts in ontologies for which potentially valuable relationships (implicit knowledge) may exist, we developed a Multi-Ontology Relatedness Model (MORM) within the knowledge network, for which a relatedness network (RN) is defined and computed across multiple ontologies using a formal inference mechanism of set-theoretic operations. Semantic constraints are designed and implemented to prune the search space of the relatedness network. Experiments to test examples of several biomedical applications have been carried out, and the evaluation of the results showed an encouraging potential of the proposed approach to biomedical knowledge discovery.

Comparison of different liquid hydrogen tank integration concepts for the ELAC-1 research configuration

NASA Astrophysics Data System (ADS)

Albus, J.; Oery, H.

1993-04-01

One of the main problems associated with the structural design of a hypersonic aircraft is the conception of the cryogenic tank. Therefore two essential questions, in consideration of structural weight, volumetric efficiency and the aspects as well of inspection, maintenance and repair, as of exchangeability in case of leakage (leak before burst) and safety in operation, have to be answered. These questions concern the choice of the tank integration concept and the tank cross section. To get an idea how much the take-off weight depends on the tank integration concept, at the Institut fuer Leichtbau of the RWTH Aachen a program for weight estimation of hypersonic aircraft has been developed. Herewith the goal was to define well suited substitute models which allow the performance of parametric studies within a wide range of parameters in a tolerable amount of time. In the following the mass model and calculation methods used will be shortly introduced and finally the results achieved will be presented and discussed. On this occasion also comments on structural efficiency of different tank cross sections will be given.

Diagnostic Reasoning across the Medical Education Continuum.

PubMed

Smith, C Scott; Hill, William; Francovich, Chris; Morris, Magdalena; Robbins, Bruce; Robins, Lynne; Turner, Andrew

2014-07-15

We aimed to study linguistic and non-linguistic elements of diagnostic reasoning across the continuum of medical education. We performed semi-structured interviews of premedical students, first year medical students, third year medical students, second year internal medicine residents, and experienced faculty (ten each) as they diagnosed three common causes of dyspnea. A second observer recorded emotional tone. All interviews were digitally recorded and blinded transcripts were created. Propositional analysis and concept mapping were performed. Grounded theory was used to identify salient categories and transcripts were scored with these categories. Transcripts were then unblinded. Systematic differences in propositional structure, number of concept connections, distribution of grounded theory categories, episodic and semantic memories, and emotional tone were identified. Summary concept maps were created and grounded theory concepts were explored for each learning level. We identified three major findings: (1) The "apprentice effect" in novices (high stress and low narrative competence); (2) logistic concept growth in intermediates; and (3) a cognitive state transition (between analytical and intuitive approaches) in experts. These findings warrant further study and comparison.

Validating two questions in the Force Concept Inventory with subquestions

NASA Astrophysics Data System (ADS)

Yasuda, Jun-ichiro; Taniguchi, Masa-aki

2013-06-01

In this study, we evaluate the structural validity of Q.16 and Q.7 in the Force Concept Inventory (FCI). We address whether respondents who answer Q.16 and Q.7 correctly actually have an understanding of the concepts of physics tested in the questions. To examine respondents’ levels of understanding, we use subquestions that test them on concepts believed to be required to answer the actual FCI questions. Our sample size comprises 111 respondents; we derive false-positive ratios for prelearners and postlearners and then statistically test the difference between them. We find a difference at the 0.05 significance level for both Q.16 and Q.7, implying that it is possible for postlearners to answer both questions without an understanding of the concepts of physics tested in the questions; therefore, the structures of Q.16 and Q.7 are invalid. In this study, we only evaluate the validity of these two FCI questions; we do not assess the validity of previous studies that have compared total FCI scores.

Building information modelling (BIM) after ten years: Malaysian construction players’ perception of BIM

NASA Astrophysics Data System (ADS)

Latiffi, A. Ahmad; Brahim, J.; Fathi, M. S.

2017-08-01

Building Information Modelling (BIM) concept has expanded widely in many countries for more than a decade with its role of improving current practices in construction projects. However, the understanding of BIM differs among construction players, depending on how construction players utilize the concept in their projects. Therefore, this paper aims to explore the understanding of BIM concept among construction players in the Malaysian construction industry. A literature review on BIM concept and semi-structured interviews with construction players in BIM such as client, civil and structural (C&S) engineer and mechanical and electrical (M&E) engineer, quantity surveyor (QS), contractor, facilities manager and BIM consultant have been conducted in order to achieve this study’s the aim. The results show that the understanding of BIM concept among the construction players is limited to BIM as a process and technology. It is important for the construction players to improve their understanding of BIM as it can be used to enhance performance and productivity of construction projects.

Distributed multifunctional sensor network for composite structural state sensing

NASA Astrophysics Data System (ADS)

Qing, Xinlin P.; Wang, Yishou; Gao, Limin; Kumar, Amrita

2012-04-01

Advanced fiber reinforced composite materials are becoming the main structural materials of next generation of aircraft because of their high strength and stiffness to weight ratios, and strong designability. In order to take full advantages of composite materials, there is a need to develop an embeddable multifunctional sensing system to allow a structure to "feel" and "think" its structural state. In this paper, the concept of multifunctional sensor network integrated with a structure, similar to the human nervous system, has been developed. Different types of network sensors are permanently integrated within a composite structure to sense structural strain, temperature, moisture, aerodynamic pressure; monitor external impact on the structure; and detect structural damages. Utilizing this revolutionary concept, future composite structures can be designed and manufactured to provide multiple modes of information, so that the structures have the capabilities for intelligent sensing, environmental adaptation and multi-functionality. The challenges for building such a structural state sensing system and some solutions to address the challenges are also discussed in the paper.

Investigation of the Cognitive Structures of Prospective Preschool Teachers on the Concepts of Circle, Disk and Annulus with the Word Association Test

ERIC Educational Resources Information Center

Gok Colak, Feride; Tugluk, Mehmet Nur

2017-01-01

This study aimed to investigate the cognitive structures of prospective preschool teachers and to identify their misconceptions about the concepts of circle, disk and annulus. In the study, the Word Association Test was used as the data collection instrument. The study was conducted in the fall semester of the 2014-2015 academic year with the…

Investigation of Pre-Service English Language Teachers' Cognitive Structures about Some Key Concepts in Approaches and Methods in Language Teaching Course through Word Association Test

ERIC Educational Resources Information Center

Ersanli, Ceylan Yangin

2016-01-01

This study aims to map the cognitive structure of pre-service English language (EL) teachers about three key concepts related to approaches and methods in language teaching so as to discover their learning process and misconceptions. The study involves both qualitative and quantitative data. The researcher administrated a Word Association Test…

Consolidation of graphite thermoplastic textile preforms for primary aircraft structure

NASA Technical Reports Server (NTRS)

Suarez, J.; Mahon, J.

1991-01-01

The use of innovative cost effective material forms and processes is being considered for fabrication of future primary aircraft structures. Processes that have been identified as meeting these goals are textile preforms that use resin transfer molding (RTM) and consolidation forming. The Novel Composites for Wing and Fuselage Applications (NCWFA) program has as its objective the integration of innovative design concepts with cost effective fabrication processes to develop damage-tolerant structures that can perform at a design ultimate strain level of 6000 micro-inch/inch. In this on-going effort, design trade studies were conducted to arrive at advanced wing designs that integrate new material forms with innovative structural concepts and cost effective fabrication methods. The focus has been on minimizing part count (mechanical fasteners, clips, number of stiffeners, etc.), by using cost effective textile reinforcement concepts that provide improved damage tolerance and out-of-plane load capability, low-cost resin transfer molding processing, and thermoplastic forming concepts. The fabrication of representative Y spars by consolidation methods will be described. The Y spars were fabricated using AS4 (6K)/PEEK 150g commingled angle interlock 0/90-degree woven preforms with +45-degree commingled plies stitched using high strength Toray carbon thread and processed by autoclave consolidation.

A study of concept-based similarity approaches for recommending program examples

NASA Astrophysics Data System (ADS)

Hosseini, Roya; Brusilovsky, Peter

2017-07-01

This paper investigates a range of concept-based example recommendation approaches that we developed to provide example-based problem-solving support in the domain of programming. The goal of these approaches is to offer students a set of most relevant remedial examples when they have trouble solving a code comprehension problem where students examine a program code to determine its output or the final value of a variable. In this paper, we use the ideas of semantic-level similarity-based linking developed in the area of intelligent hypertext to generate examples for the given problem. To determine the best-performing approach, we explored two groups of similarity approaches for selecting examples: non-structural approaches focusing on examples that are similar to the problem in terms of concept coverage and structural approaches focusing on examples that are similar to the problem by the structure of the content. We also explored the value of personalized example recommendation based on student's knowledge levels and learning goal of the exercise. The paper presents concept-based similarity approaches that we developed, explains the data collection studies and reports the result of comparative analysis. The results of our analysis showed better ranking performance of the personalized structural variant of cosine similarity approach.

Enhancing Interoperability Through Standard Procedures for Recording and Communicating Information on V&V Planning, Implementation and Results

DTIC Science & Technology

2003-11-01

are used in the ITOP [8], these are a “V&V cases” concept, a “claim-argument-evidence” structure, and a “ levels ” concept for the classification of M&S...obtained from the V&V effort. A levels concept assists in communication and understanding between parties in discussion. It also provides a convenient...piece of evidence obtained from the V&V effort. 13-9 Concepts behind the V&V ITOP document • A levels concept assists in communication and understanding

Inside Titan Author Concept

NASA Image and Video Library

2012-06-28

This artist concept shows a possible scenario for the internal structure of Titan, as suggested by data from NASA Cassini spacecraft. Scientists have been trying to determine what is under Titan organic-rich atmosphere and icy crust.

Passive damping concepts for tubular beams with partial rotational and translational end restraints

NASA Technical Reports Server (NTRS)

Razzaq, Zia; Muyundo, David K.

1991-01-01

The main objectives of the study are: (1) identification of potential passive damping concepts for slender tubular structural members with rotational and translational end springs under natural and forced-free vibrations; (2) evaluation of damping efficiencies of the various damping concepts; and (3) evaluation of the suitability of a theoretical finite difference analysis by comparison to the experimental results for the case of natural vibrations. Only member flexural an translation motion is considered. The natural vibration study is conducted on the seven damping concepts and for only one specific initial deflection. The most suitable of the seven dampers is further investigated under forced-free vibrations. In addition only one set of end springs is used for all of the experiments. The results show that passive damping provides a possible approach to structural vibration reduction.

Quality assurance of chemical ingredient classification for the National Drug File - Reference Terminology.

PubMed

Zheng, Ling; Yumak, Hasan; Chen, Ling; Ochs, Christopher; Geller, James; Kapusnik-Uner, Joan; Perl, Yehoshua

2017-09-01

The National Drug File - Reference Terminology (NDF-RT) is a large and complex drug terminology consisting of several classification hierarchies on top of an extensive collection of drug concepts. These hierarchies provide important information about clinical drugs, e.g., their chemical ingredients, mechanisms of action, dosage form and physiological effects. Within NDF-RT such information is represented using tens of thousands of roles connecting drugs to classifications. In previous studies, we have introduced various kinds of Abstraction Networks to summarize the content and structure of terminologies in order to facilitate their visual comprehension, and support quality assurance of terminologies. However, these previous kinds of Abstraction Networks are not appropriate for summarizing the NDF-RT classification hierarchies, due to its unique structure. In this paper, we present the novel Ingredient Abstraction Network (IAbN) to summarize, visualize and support the audit of NDF-RT's Chemical Ingredients hierarchy and its associated drugs. A common theme in our quality assurance framework is to use characterizations of sets of concepts, revealed by the Abstraction Network structure, to capture concepts, the modeling of which is more complex than for other concepts. For the IAbN, we characterize drug ingredient concepts as more complex if they belong to IAbN groups with multiple parent groups. We show that such concepts have a statistically significantly higher rate of errors than a control sample and identify two especially common patterns of errors. Copyright © 2017 Elsevier Inc. All rights reserved.

Perception of Mobbing by Teachers and Organizational Depression: A Correlational Model Study

ERIC Educational Resources Information Center

Toytok, Esef Hakan

2017-01-01

As is known, mobbing (intimidation) is an important concept being subject to many researches in numerous fields and many researchers suggest that this concept has the power to directly affect organizational structures. Even though the concept of mobbing changes from country to country, culture to culture and organization to organization, it is…

Adolescents and Music Media: Toward an Involvement-Mediational Model of Consumption and Self-Concept

ERIC Educational Resources Information Center

Kistler, Michelle; Rodgers, Kathleen Boyce; Power, Thomas; Austin, Erica Weintraub; Hill, Laura Griner

2010-01-01

Using social cognitive theory and structural regression modeling, we examined pathways between early adolescents' music media consumption, involvement with music media, and 3 domains of self-concept (physical appearance, romantic appeal, and global self-worth; N=124). A mediational model was supported for 2 domains of self-concept. Music media…

Surfacing the Structures of Patriarchy: Teaching and Learning Threshold Concepts in Women's Studies

ERIC Educational Resources Information Center

Hassel, Holly; Reddinger, Amy; van Slooten, Jessica

2011-01-01

Patriarchy is a threshold concept in women's studies--a significant, defining concept that transforms students' understanding of the discipline. This article reviews our design, implementation, and findings of a lesson study crafted to teach women's studies students the complex idea of patriarchy as a social system. We analyze the lesson using…

Exploring South African High School Teachers' Conceptions of the Nature of Scientific Inquiry: A Case Study

ERIC Educational Resources Information Center

Dudu, Washington T.

2014-01-01

The paper explores conceptions of the nature of scientific inquiry (NOSI) held by five teachers who were purposively and conveniently sampled. Teachers' conceptions of the NOSI were determined using a Probes questionnaire. To confirm teachers' responses, a semi-structured interview was conducted with each teacher. The Probes questionnaire was…

Acoustic emission analysis as a non-destructive test procedure for fiber compound structures

NASA Technical Reports Server (NTRS)

Block, J.

1983-01-01

The concept of acoustic emission analysis is explained in scientific terms. The detection of acoustic events, their localization, damage discrimination, and event summation curves are discussed. A block diagram of the concept of damage-free testing of fiber-reinforced synthetic materials is depicted. Prospects for application of the concept are assessed.

Organic Chemistry Students' Fragmented Ideas about the Structure and Function of Nucleophiles and Electrophiles: A Concept Map Analysis

ERIC Educational Resources Information Center

Anzovino, Mary E.; Bretz, Stacey Lowery

2016-01-01

Organic chemistry students struggle with multiple aspects of reaction mechanisms and the curved arrow notation used by organic chemists. Many faculty believe that an understanding of nucleophiles and electrophiles, among other concepts, is required before students can develop fluency with the electronpushing formalism (EPF). An expert concept map…

Analysis of Secondary School Students' Perceptions about Information Technologies through a Word Association Test

ERIC Educational Resources Information Center

Eren, Fetah; Sahin, Ismail; Celik, Ismail; Akturk, Ahmet Oguz

2014-01-01

The aim of this study is to discover secondary school students' perceptions related to information technologies and the connections between concepts in their cognitive structures. A word association test consisting of six concepts related to information technologies is used to collect data from 244 secondary school students. Concept maps that…

An Investigation of Concept Mapping to Improve the Reading Comprehension of Science Texts

ERIC Educational Resources Information Center

Oliver, Kevin

2009-01-01

This study investigated how well 74 6th-grade science students represented text structures from a 900-word textbook chapter on soil conservation, given a concept map template with four superordinate terms and 24 unsorted concepts. Findings suggest students were more successful at classifying pre-selected terms under given superordinate categories…

"Blame" Concept in Phraseology: Cognitive-Semantic Aspect (Based on the French Language)

ERIC Educational Resources Information Center

Zalavina, Tatyana Y.; Kisel, Olesya V.

2016-01-01

Phraseology is one of the basic and most important objects of study in cognitive linguistics. The article deals with verbal fixed phrases in their correlation with the cognitive structure of knowledge--a concept. The used definitional analysis method to identify the basic notions of the conceptual content of the concept of blame and basic…

An Investigation of the Hierarchical and Developmental Structure of Selected Science Concepts.

ERIC Educational Resources Information Center

Griffiths, Alan Keith

This report describes the results of an attempt to identify a learning hierarchy for each of a number of science concepts mainly encountered first in the high school grades. The concepts studied relate to stoichiometric calculations and molarity, both from chemistry; to food web relationships and problems involving Mendel's laws from biology; to…

The (Homo)Morphism Concept: Didactic Transposition, Meta-Discourse and Thematisation

ERIC Educational Resources Information Center

Hausberger, Thomas

2017-01-01

This article focuses on the didactic transposition of the homomorphism concept and on the elaboration and evaluation of an activity dedicated to the teaching of this fundamental concept in Abstract Algebra. It does not restrict to Group Theory but on the contrary raises the issue of the teaching and learning of algebraic structuralism, thus…

An Analysis, Using Concept Mapping, of Diabetic Patients' Knowledge, before and after Patient Education.

ERIC Educational Resources Information Center

Marchand, C.; d'Ivernois, J. F.; Assal, J. P.; Slama, G.; Hivon, R.

2002-01-01

Assesses whether concept maps used with diabetic patients could describe their cognitive structure, before and after having followed an educational program. Involves 10 diabetic patients and shows that concept maps can be a suitable technique to explore the type and organization of the patients' prior knowledge and to visualize what they have…

Developmental Growth in Students' Concept of Energy: Analysis of Selected Items from the TIMSS Database

ERIC Educational Resources Information Center

Liu, Xiufeng; McKeough, Anne

2005-01-01

The aim of this study was to develop a model of students' energy concept development. Applying Case's (1985, 1992) structural theory of cognitive development, we hypothesized that students' concept of energy undergoes a series of transitions, corresponding to systematic increases in working memory capacity. The US national sample from the Third…

The Effects of Recycling and Response Sensitivity on the Acquisition of Social Studies Concepts.

ERIC Educational Resources Information Center

Ford, Mary Jane; McKinney, C. Warren

1986-01-01

Two studies are reported which investigate the concept learning of 116 sixth graders (study 1) and 107 second graders (study 2) depending on the model of concept presentation. Results showed no difference between the structured Merrill and Tennyson model and adaptations of the model which were responsive to student's questions or recycled missed…

The Relation between Self-Concept and Social Functioning in Adolescence

ERIC Educational Resources Information Center

Ybrandt, H.

2008-01-01

A model of the relation between self-concept and internalizing and externalizing problem behaviours in adolescence, with the self-concept influencing problem behaviours (S[right arrow]IE), was assessed using a sample of 277 Swedish adolescents. The model was tested in a path analysis with data from Youth Self Report (YSR) and Structural Analysis…

Analysis of the Educational Implications of the Concept of Scientific Revolutions.

ERIC Educational Resources Information Center

Prather, J. Preston

This paper is based on the work of Thomas Kuhn, a physicist turned philosopher and historian of science. In his book, "The Structure of Scientific Revolution," he posited a new concept of the nature and history of science and strongly criticized the current textbook tradition of science education. This study analyzed Kuhn's concept of…

Concept Development in Learning Physics: The Case of Electric Current and Voltage Revisited

ERIC Educational Resources Information Center

Koponen, Ismo T.; Huttunen, Laura

2013-01-01

In learning conceptual knowledge in physics, a common problem is the development and differentiation of concepts in the learning process. An important part of this development process is the re-organisation or re-structuring process in which students' conceptual knowledge and concepts change. This study proposes a new view of concept…

Titration of a Solid Acid Monitored by X-Ray Diffraction

ERIC Educational Resources Information Center

Dungey, Keenan E.; Epstein, Paul

2007-01-01

An experiment is described to introduce students to an important class of solid-state reactions while reinforcing concepts of titration by using a pH meter and a powder X-ray diffractometer. The experiment was successful in teaching students the abstract concepts of solid-state structure and diffraction by applying the diffraction concepts learned…

Classification of proteins: available structural space for molecular modeling.

PubMed

Andreeva, Antonina

2012-01-01

The wealth of available protein structural data provides unprecedented opportunity to study and better understand the underlying principles of protein folding and protein structure evolution. A key to achieving this lies in the ability to analyse these data and to organize them in a coherent classification scheme. Over the past years several protein classifications have been developed that aim to group proteins based on their structural relationships. Some of these classification schemes explore the concept of structural neighbourhood (structural continuum), whereas other utilize the notion of protein evolution and thus provide a discrete rather than continuum view of protein structure space. This chapter presents a strategy for classification of proteins with known three-dimensional structure. Steps in the classification process along with basic definitions are introduced. Examples illustrating some fundamental concepts of protein folding and evolution with a special focus on the exceptions to them are presented.

HabEx Optical Telescope Concepts: Design and Performance Analysis

NASA Astrophysics Data System (ADS)

Stahl, H. Philip; NASA MSFC HabEx Telescope Design Team

2018-01-01

The Habitable-Exoplanet Imaging Mission (HabEx) engineering study team has been tasked by NASA with developing a compelling and feasible exoplanet direct imaging concept as part of the 2020 Decadal Survey. This paper summarizes design concepts for two off-axis unobscured telescope concepts: a 4-meter monolithic aperture and a 6-meter segmented aperutre. HabEx telescopes are designed for launch vehicle accommodation. Analysis includes prediction of on-orbit dynamic structural and thermal optical performance.

Using Concept Space to Verify Hyponymy in Building a Hyponymy Lexicon

NASA Astrophysics Data System (ADS)

Liu, Lei; Zhang, Sen; Diao, Lu Hong; Yan, Shu Ying; Cao, Cun Gen

Verification of hyponymy relations is a basic problem in knowledge acquisition. We present a method of hyponymy verification based on concept space. Firstly, we give the definition of concept space about a group of candidate hyponymy relations. Secondly we analyze the concept space and define a set of hyponymy features based on the space structure. Then we use them to verify candidate hyponymy relations. Experimental results show that the method can provide adequate verification of hyponymy.

On the concept of individual in ecology and evolution.

PubMed

Metz, J A J

2013-03-01

Part of the art of theory building is to construct effective basic concepts, with a large reach and yet powerful as tools for getting at conclusions. The most basic concept of population biology is that of individual. An appropriately reengineered form of this concept has become the basis for the theories of structured populations and adaptive dynamics. By appropriately delimiting individuals, followed by defining their states as well as their environment, it become possible to construct the general population equations that were introduced and studied by Odo Diekmann and his collaborators. In this essay I argue for taking the properties that led to these successes as the defining characteristics of the concept of individual, delegating the properties classically invoked by philosophers to the secondary role of possible empirical indicators for the presence of those characteristics. The essay starts with putting in place as rule for effective concept engineering that one should go for relations that can be used as basis for deductive structure building rather than for perceived ontological essence. By analysing how we want to use it in the mathematical arguments I then build up a concept of individual, first for use in population dynamical considerations and then for use in evolutionary ones. These two concepts do not coincide, and neither do they on all occasions agree with common intuition-based usage.

Conformal Cryogenic Tank Trade Study for Reusable Launch Vehicles

NASA Technical Reports Server (NTRS)

Rivers, H. Kevin

1999-01-01

Future reusable launch vehicles may be lifting bodies with non-circular cross section like the proposed Lockheed-Martin VentureStar(tm). Current designs for the cryogenic tanks of these vehicles are dual-lobed and quad-lobed tanks which are packaged more efficiently than circular tanks, but still have low packaging efficiencies with large gaps existing between the vehicle outer mold line and the outer surfaces of the tanks. In this study, tanks that conform to the outer mold line of a non-circular vehicle were investigated. Four structural concepts for conformal cryogenic tanks and a quad-lobed tank concept were optimized for minimum weight designs. The conformal tank concepts included a sandwich tank stiffened with axial tension webs, a sandwich tank stiffened with transverse tension webs, a sandwich tank stiffened with rings and tension ties, and a sandwich tank stiffened with orthogrid stiffeners and tension ties. For each concept, geometric parameters (such as ring frame spacing, the number and spacing of tension ties or webs, and tank corner radius) and internal pressure loads were varied and the structure was optimized using a finite-element-based optimization procedure. Theoretical volumetric weights were calculated by dividing the weight of the barrel section of the tank concept and its associated frames, webs and tension ties by the volume it circumscribes. This paper describes the four conformal tank concepts and the design assumptions utilized in their optimization. The conformal tank optimization results included theoretical weights, trends and comparisons between the concepts, are also presented, along with results from the optimization of a quad-lobed tank. Also, the effects of minimum gauge values and non-optimum weights on the weight of the optimized structure are described in this paper.

FY-79 - development of fiber optics connector technology for large space systems

NASA Technical Reports Server (NTRS)

Campbell, T. G.

1980-01-01

The development of physical concepts for integrating fiber optic connectors and cables with structural concepts proposed for the LSST is discussed. Emphasis is placed on remote connections using integrated cables.

Spacelab software development and integration concepts study report. Volume 2: Appendices

NASA Technical Reports Server (NTRS)

1973-01-01

Software considerations were developed for incorporation in the spacelab systems design, and include management concepts for top-down structured programming, composite designs for modular programs, and team management methods for production programming.

[Activating therapeutic care in geriatrics : Evaluation of a practice concept].

PubMed

Acklau, Stefanie; Gödecker, Lisa; Kaden, Andrea; Jahn, Patrick

2016-10-01

The special feature of the concept of activating therapeutic care in geriatrics (ATP-G) is based on the focus of nursing and therapeutic elements specifically related to the elderly. Further significance lies in the bottom-up development of this concept, which shows a close proximity to the nursing practice. The research project targeted the characteristics of ATP-G from a nursing point of view. Furthermore, the resulting elements of professional nursing care understanding for inpatient geriatric rehabilitation were used to build a scientific and theoretical foundation of the ATP-G concept. In this study 12 semi-structured interviews with professional caregivers were realized. The data collection was undertaken in three different facilities of inpatient geriatric (early) rehabilitation, chosen by lot. The data analysis was based on the methodology of qualitative content analysis according to Mayring. The research project showed that the basic elements described in the ATP-G concept are consistent with the view of nursing practitioners and therefore reflect the characteristic features of routine daily practice; nonetheless, some new aspects were found, primarily the importance of interdisciplinary teamwork in geriatric settings. There were also difficulties related to the ATP-G concept which were experienced as restraints by the questioned professionals. Further research should therefore investigate the structures for optimal implementation of the ATP-G concept into standard practice.

Relating Complexity and Error Rates of Ontology Concepts. More Complex NCIt Concepts Have More Errors.

PubMed

Min, Hua; Zheng, Ling; Perl, Yehoshua; Halper, Michael; De Coronado, Sherri; Ochs, Christopher

2017-05-18

Ontologies are knowledge structures that lend support to many health-information systems. A study is carried out to assess the quality of ontological concepts based on a measure of their complexity. The results show a relation between complexity of concepts and error rates of concepts. A measure of lateral complexity defined as the number of exhibited role types is used to distinguish between more complex and simpler concepts. Using a framework called an area taxonomy, a kind of abstraction network that summarizes the structural organization of an ontology, concepts are divided into two groups along these lines. Various concepts from each group are then subjected to a two-phase QA analysis to uncover and verify errors and inconsistencies in their modeling. A hierarchy of the National Cancer Institute thesaurus (NCIt) is used as our test-bed. A hypothesis pertaining to the expected error rates of the complex and simple concepts is tested. Our study was done on the NCIt's Biological Process hierarchy. Various errors, including missing roles, incorrect role targets, and incorrectly assigned roles, were discovered and verified in the two phases of our QA analysis. The overall findings confirmed our hypothesis by showing a statistically significant difference between the amounts of errors exhibited by more laterally complex concepts vis-à-vis simpler concepts. QA is an essential part of any ontology's maintenance regimen. In this paper, we reported on the results of a QA study targeting two groups of ontology concepts distinguished by their level of complexity, defined in terms of the number of exhibited role types. The study was carried out on a major component of an important ontology, the NCIt. The findings suggest that more complex concepts tend to have a higher error rate than simpler concepts. These findings can be utilized to guide ongoing efforts in ontology QA.

Cognitive flexibility and undergraduate physiology students: increasing advanced knowledge acquisition within an ill-structured domain.

PubMed

Rhodes, Ashley E; Rozell, Timothy G

2017-09-01

Cognitive flexibility is defined as the ability to assimilate previously learned information and concepts to generate novel solutions to new problems. This skill is crucial for success within ill-structured domains such as biology, physiology, and medicine, where many concepts are simultaneously required for understanding a complex problem, yet the problem consists of patterns or combinations of concepts that are not consistently used or needed across all examples. To succeed within ill-structured domains, a student must possess a certain level of cognitive flexibility: rigid thought processes and prepackaged informational retrieval schemes relying on rote memorization will not suffice. In this study, we assessed the cognitive flexibility of undergraduate physiology students using a validated instrument entitled Student's Approaches to Learning (SAL). The SAL evaluates how deeply and in what way information is processed, as well as the investment of time and mental energy that a student is willing to expend by measuring constructs such as elaboration and memorization. Our results indicate that students who rely primarily on memorization when learning new information have a smaller knowledge base about physiological concepts, as measured by a prior knowledge assessment and unit exams. However, students who rely primarily on elaboration when learning new information have a more well-developed knowledge base about physiological concepts, which is displayed by higher scores on a prior knowledge assessment and increased performance on unit exams. Thus students with increased elaboration skills possibly possess a higher level of cognitive flexibility and are more likely to succeed within ill-structured domains. Copyright © 2017 the American Physiological Society.

The fabrication of a programmable via using phase-change material in CMOS-compatible technology.

PubMed

Chen, Kuan-Neng; Krusin-Elbaum, Lia

2010-04-02

We demonstrate an energy-efficient programmable via concept using indirectly heated phase-change material. This via structure has maximum phase-change volume to achieve a minimum on resistance for high performance logic applications. Process development and material investigations for this device structure are reported. The device concept is successfully demonstrated in a standard CMOS-compatible technology capable of multiple cycles between on/off states for reconfigurable applications.

Manned orbital systems concepts study. Book 3: Configurations for extended duration missions. [mission planning and project planning for space missions

NASA Technical Reports Server (NTRS)

1975-01-01

Mission planning, systems analysis, and design concepts for the Space Shuttle/Spacelab system for extended manned operations are described. Topics discussed are: (1) payloads, (2) spacecraft docking, (3) structural design criteria, (4) life support systems, (5) power supplies, and (6) the role of man in long duration orbital operations. Also discussed are the assembling of large structures in space. Engineering drawings are included.

The Application of Artificial Intelligence to the Management of the Army’s Mobile Subscriber Equipment Communications System

DTIC Science & Technology

1992-06-01

and may be better suited for knowledge representation. Frames Researcher Marvin Minsky developed the concept of Frames to describe how humans organize...knowledge about common concepts and situations.’ Minsky hypothesized that people do not construct new knowledge structures from scratch when they...to store new information. Minsky called these knowledge structures frames. Frames can be viewed as complex semantic nets. Frame diagrams show the

Changing concepts of geologic structure and the problem of siting nuclear reactors: Examples from Washington State

NASA Astrophysics Data System (ADS)

Tabor, R. W.

1986-09-01

The conflict between regulation and healthy evolution of geological science has contributed to the difficulties of siting nuclear reactors. On the Columbia Plateau in Washington, but for conservative design of the Hanford reactor facility, the recognition of the little-understood Olympic-Wallowa lineament as a major, possibly still active structural alinement might have jeopardized the acceptability of the site for nuclear reactors. On the Olympic Peninsula, evolving concepts of compressive structures and their possible recent activity and the current recognition of a subducting Juan de Fuca plate and its potential for generating great earthquakes—both concepts little-considered during initial site selection—may delay final acceptance of the Satsop site. Conflicts of this sort are inevitable but can be accommodated if they are anticipated in the reactor-licensing process. More important, society should be increasing its store of geologic knowledge now, during the current recess in nuclear reactor siting.

New isostatic mounting concept for a space born Three Mirror Anastigmat (TMA) on the Meteosat Third Generation Infrared Sounder Instrument (MTG-IRS)

NASA Astrophysics Data System (ADS)

Freudling, Maximilian; Klammer, Jesko; Lousberg, Gregory; Schumacher, Jean-Marc; Körner, Christian

2016-07-01

A novel isostatic mounting concept for a space born TMA of the Meteosat Third Generation Infrared Sounder is presented. The telescope is based on a light-weight all-aluminium design. The mounting concept accommodates the telescope onto a Carbon-Fiber-Reinforced Polymer (CRFP) structure. This design copes with the high CTE mismatch without introducing high stresses into the telescope structure. Furthermore a Line of Sight stability of a few microrads under geostationary orbit conditions is provided. The design operates with full performance at a temperature 20K below the temperature of the CFRP structure and 20K below the integration temperature. The mounting will sustain launch loads of 47g. This paper will provide the design of the Back Telescope Assembly (BTA) isostatic mounting and will summarise the consolidated technical baseline reached following a successful Preliminary Design Review (PDR).

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.

Waveguide metatronics: Lumped circuitry based on structural dispersion.

PubMed

Li, Yue; Liberal, Iñigo; Della Giovampaola, Cristian; Engheta, Nader

2016-06-01

Engineering optical nanocircuits by exploiting modularization concepts and methods inherited from electronics may lead to multiple innovations in optical information processing at the nanoscale. We introduce the concept of "waveguide metatronics," an advanced form of optical metatronics that uses structural dispersion in waveguides to obtain the materials and structures required to construct this class of circuitry. Using numerical simulations, we demonstrate that the design of a metatronic circuit can be carried out by using a waveguide filled with materials with positive permittivity. This includes the implementation of all "lumped" circuit elements and their assembly in a single circuit board. In doing so, we extend the concepts of optical metatronics to frequency ranges where there are no natural plasmonic materials available. The proposed methodology could be exploited as a platform to experimentally validate optical metatronic circuits in other frequency regimes, such as microwave frequency setups, and/or to provide a new route to design optical nanocircuitry.

Concept Definition Study for In-Space Structural Characterization of a Lightweight Solar Array

NASA Technical Reports Server (NTRS)

Woods-Vedeler, Jessica A.; Pappa, Richard S.; Jones, Thomas W.; Spellman, Regina; Scott, Willis; Mockensturm, Eric M.; Liddle, Donn; Oshel, Ed; Snyder, Michael

2002-01-01

A Concept Definition Study (CDS) was conducted to develop a proposed "Lightweight High-Voltage Stretched-Lens Concentrator Solar Array Experiment" under NASA's New Millennium Program Space Technology-6 (NMP ST-6) activity. As part of a multi-organizational team, NASA Langley Research Center's role in this proposed experiment was to lead Structural Characterization of the solar array during the flight experiment. In support of this role, NASA LaRC participated in the CDS to de.ne an experiment for static, dynamic, and deployment characterization of the array. In this study, NASA LaRC traded state-of-the-art measurement approaches appropriate for an in-space, STS-based flight experiment, provided initial analysis and testing of the lightweight solar array and lens elements, performed a lighting and photogrammetric simulation in conjunction with JSC, and produced an experiment concept definition to meet structural characterization requirements.

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

Peter H. Titus and Ali Zolfaghari

A critical design feature of any tokamak is the space taken up by the inner leg of the toroidal field (TF) coil. The radial build needed for the TF inner leg, along with shield thickness , size of the central solenoid and plasma minor radius set the major radius of the machine. The cost of the tokamak core roughly scales with the cube of the major radius. Small reductions in the TF build can have a big impact on the overall cost of the reactor. The cross section of the TF inner leg must structurally support the centering force andmore » that portion of the vertical separating force that is not supported by the outer structures. In this paper, the TF inner leg equatorial plane cross sections are considered. Out-of- Plane (OOP) forces must also be supported, but these are largest away from the equatorial plane, in the inner upper and lower corners and outboard sections of the TF coil. OOP forces are taken by structures that are not closely coupled with the radial build of the central column at the equatorial plane. The "Vertical Access AT Pilot Plant" currently under consideration at PPPL is used as a starting point for the structural, field and current requirements. Other TF structural concepts are considered. Most are drawn from existing designs such as ITER's circular conduits in radial plates bearing on a heavy nose section, and TPX's square conduits in a case, Each of these concepts can rely on full wedging, or partial wedging. Vaulted TF coils are considered as are those with some component of bucking against a central solenoid or bucking post. With the expectation that the pilot plant will be a steady state machine, a static stress criteria is used for all the concepts. The coils are assumed to be superconducting, with the superconductor not contributing to the structural strength. Limit analysis is employed to assess the degree of conservatism in the static criteria as it is applied to a linear elastic stress analysis. TF concepts, and in particular the PPPL AT PILOT plate concept are evaluated based on amount of space needed for structure and the amount of space left for superconductor.« less

A generalized concept for cost-effective structural design. [Statistical Decision Theory applied to aerospace systems

NASA Technical Reports Server (NTRS)

Thomas, J. M.; Hawk, J. D.

1975-01-01

A generalized concept for cost-effective structural design is introduced. It is assumed that decisions affecting the cost effectiveness of aerospace structures fall into three basic categories: design, verification, and operation. Within these basic categories, certain decisions concerning items such as design configuration, safety factors, testing methods, and operational constraints are to be made. All or some of the variables affecting these decisions may be treated probabilistically. Bayesian statistical decision theory is used as the tool for determining the cost optimum decisions. A special case of the general problem is derived herein, and some very useful parametric curves are developed and applied to several sample structures.

Satellite Power System (SPS) concept definition study (Exhibit D). Volume 2: Systems/subsystems analyses

NASA Technical Reports Server (NTRS)

Hanley, G. M.

1981-01-01

Modifications to the reference concept were studied and the best approaches defined. The impact of the high efficiency multibandgap solar array on the reference concept design is considered. System trade studies for several solid state concepts, including the sandwich concept and a separate antenna/solar concept, are described. Two solid state concepts were selected and a design definition is presented for each. Magnetrons as an alternative to the reference klystrons for dc/RF conversion are evaluated. System definitions are presented for the preferred klystron and solid state concepts. Supporting systems are analyzed, with major analysis in the microwave, structures, and power distribution areas. Results of studies for thermal control, attitude control, stationkeeping, and details of a multibandgap solar cell study are included. Advanced laser concepts and the meteorological effects of a laser beam power transmission concept are considered.

[Geriatric health care structures in Germany. The cross-border cooperation in geriatric medicine as a needs-driven further development].

PubMed

van den Heuvel, D; Veer, A; Greuel, H-W

2014-01-01

To cover future needs of specialised geriatric patient-centred care, existing structures need to be developed further. Taking into account regional structures of providing care, the Federal Association of Geriatric Medicine in Germany developed the concept of Cross-Border Cooperation in Geriatric Medicine. This concept combines specific geriatric expertise provided by inpatient health care with specialised networking in ambulatory treatment of elderly with a typical geriatric profile. The objective is to provide geriatric patients with a holistic and specific care and case management that overcomes existing limitations.

Using the Concept Map Technique in Teaching Introductory Cell Biology to College Freshmen

ERIC Educational Resources Information Center

Yarden, Hagit; Marbach-Ad, Gili; Gershoni, Jonathan M.

2004-01-01

In our study, we focused on the conceptual understanding of the concepts and processes presented in the first lectures of an introductory course in cellular biology for biology majors. The study topic we considered was, "the structure of DNA and the functions of nucleotides". One hundred and eighteen students were asked to prepare concept maps…

Validating Two Questions in the Force Concept Inventory with Subquestions

ERIC Educational Resources Information Center

Yasuda, Jun-ichiro; Taniguchi, Masa-aki

2013-01-01

In this study, we evaluate the structural validity of Q.16 and Q.7 in the Force Concept Inventory (FCI). We address whether respondents who answer Q.16 and Q.7 correctly actually have an understanding of the concepts of physics tested in the questions. To examine respondents' levels of understanding, we use subquestions that test them on concepts…

"Inhloso Kanye Bizo": Exploring South African University Students' Conceptions and Enactment of Purpose

ERIC Educational Resources Information Center

Mason, Henry D.

2017-01-01

This article reports a qualitative study that explored South African conceptions and enactment of life purpose. Data collected using semi-structured interviews with 25 first-year university students (female = 56%, age range = 18-25) offer a unique insight into African young adults' conceptions of life purpose. From a phenomenological analysis…

A Structural Model of Self-Concept, Autonomous Motivation and Academic Performance in Cross-Cultural Perspective

ERIC Educational Resources Information Center

Ahmed, Wondimu; Bruinsma, Marjon

2006-01-01

The purpose of this study was to propose and test a motivational model of performance by integrating constructs from self-concept and self-determination theories and to explore cultural group differences in the model. To this end, self-report measures of global self-esteem, academic self-concept, academic motivation and academic performance were…

Master Curriculum Guide in Economics for the Nation's Schools. Part I, A Framework for Teaching Economics: Basic Concepts.

ERIC Educational Resources Information Center

Hansen, W. Lee; And Others

A concise framework of basic concepts and generalizations for teaching economics for K-12 students is presented. The guide summarizes the basic structure and substance of economics and lists and describes economic concepts. Standard guidelines are provided to help school systems integrate economics into their on-going courses of study. Designed to…

Development of deployable structures for large space platform systems, volume 1

NASA Technical Reports Server (NTRS)

1982-01-01

Generic deployable spacecraft configurations and deployable platform systems concepts were identified. Sizing, building block concepts, orbiter packaging, thermal analysis, cost analysis, and mass properties analysis as related to platform systems integration are considered. Technology needs are examined and the major criteria used in concept selection are delineated. Requirements for deployable habitat modules, tunnels, and OTV hangars are considered.

Advanced Numerical-Algebraic Thinking: Constructing the Concept of Covariation as a Prelude to the Concept of Function

ERIC Educational Resources Information Center

Hitt, Fernando; Morasse, Christian

2009-01-01

Introduction: In this document we stress the importance of developing in children a structure for advanced numerical-algebraic thinking that can provide an element of control when solving mathematical situations. We analyze pupils' conceptions that induce errors in algebra due to a lack of control in connection with their numerical thinking. We…

Feasibility of modern airships - Preliminary assessment

NASA Technical Reports Server (NTRS)

Ardema, M. D.

1977-01-01

Attention is given to the NASA program, Feasibility Study of Modern Airships, initiated to investigate potential research and technology programs associated with airship development. A historical survey of the program is presented, including the development of past airship concepts, aerodynamical and design improvements, structure and material concepts, and research in controls, avionics, instrumentation, flight operations, and ground handling. A mission analysis was carried out which considered passenger and cargo transportation, heavy-lift, short-haul applications, surveillance missions, and the transportation of natural gas. A vehicle parametric analysis examined the entire range of airship concepts, discussing both conventional airships and hybrids. Various design options were evaluated, such as choice of structural materials, use of boundary-layer control, and choice of lifting gas.

Recent advances in approximation concepts for optimum structural design

NASA Technical Reports Server (NTRS)

Barthelemy, Jean-Francois M.; Haftka, Raphael T.

1991-01-01

The basic approximation concepts used in structural optimization are reviewed. Some of the most recent developments in that area since the introduction of the concept in the mid-seventies are discussed. The paper distinguishes between local, medium-range, and global approximations; it covers functions approximations and problem approximations. It shows that, although the lack of comparative data established on reference test cases prevents an accurate assessment, there have been significant improvements. The largest number of developments have been in the areas of local function approximations and use of intermediate variable and response quantities. It also appears that some new methodologies are emerging which could greatly benefit from the introduction of new computer architecture.

Swing-arm beam erector (SABER) concept for single astronaut assembly of space structure

NASA Technical Reports Server (NTRS)

Watson, J. J.; Heard, W. L., Jr.; Jensen, J. K.

1985-01-01

Results are presented of tests conducted to evaluate a mobile work station/assembly fixture concept that would mechanically assist an astronaut in the on-orbit manual assembly of erectable truss-beams. The concept eliminates astronaut manual translation by use of a motorized work platform with foot restraints. The tests involved assembly of a tetrahedral truss-beam by a test subject in simulated zero gravity (neutral bouyancy in water). A three-bay truss-beam was assembled from 30 aluminum struts with quick-attachment structural joints. The results show that average on-orbit assembly rates of 2.1 struts per minute can be expected for struts of the size employed in these tests.

Aeroelastic Optimization of Generalized Tube and Wing Aircraft Concepts Using HCDstruct Version 2.0

NASA Technical Reports Server (NTRS)

Quinlan, Jesse R.; Gern, Frank H.

2017-01-01

Major enhancements were made to the Higher-fidelity Conceptual Design and structural optimization (HCDstruct) tool developed at NASA Langley Research Center (LaRC). Whereas previous versions were limited to hybrid wing body (HWB) configurations, the current version of HCDstruct now supports the analysis of generalized tube and wing (TW) aircraft concepts. Along with significantly enhanced user input options for all air- craft configurations, these enhancements represent HCDstruct version 2.0. Validation was performed using a Boeing 737-200 aircraft model, for which primary structure weight estimates agreed well with available data. Additionally, preliminary analysis of the NASA D8 (ND8) aircraft concept was performed, highlighting several new features of the tool.

The ‘structure-function’ relationship in glaucoma – past thinking and current concepts

PubMed Central

Malik, Rizwan; Swanson, William H.; Garway-Heath, David F

2013-01-01

An understanding of the relationship between functional and structural measures in primary open angle glaucoma (POAG) is necessary for both grading the severity of disease and for understanding the natural history of the condition. This article outlines the current evidence for the nature of this relationship, and highlights the current mathematical models linking structure and function. Large clinical trials demonstrate that both structural and functional change are apparent in advanced stages of disease, while, at an individual level, detectable structural abnormality may precede functional abnormality in some patients whilst the converse in true in other patients. Although the exact nature of the ‘structure-function’ relationship in POAG is still the topic of scientific debate and the subject of continuing research, this article aims to provide the clinician with an understanding of the past concepts and contemporary thinking in relation to the structure-function relationship in POAG. PMID:22339936

Structural health monitoring of plates with surface features using guided ultrasonic waves

NASA Astrophysics Data System (ADS)

Fromme, P.

2009-03-01

Distributed array systems for guided ultrasonic waves offer an efficient way for the long-term monitoring of the structural integrity of large plate-like structures. The measurement concept involving baseline subtraction has been demonstrated under laboratory conditions. For the application to real technical structures it needs to be shown that the methodology works equally well in the presence of structural and surface features. Problems employing this structural health monitoring concept can occur due to the presence of additional changes in the signal reflected at undamaged parts of the structure. The influence of the signal processing parameters and transducer placement on the damage detection and localization accuracy is discussed. The use of permanently attached, distributed sensors for the A0 Lamb wave mode has been investigated. Results are presented using experimental data obtained from laboratory measurements and Finite Element simulated signals for a large steel plate with a welded stiffener.

JPL control/structure interaction test bed real-time control computer architecture

NASA Technical Reports Server (NTRS)

Briggs, Hugh C.

1989-01-01

The Control/Structure Interaction Program is a technology development program for spacecraft that exhibit interactions between the control system and structural dynamics. The program objectives include development and verification of new design concepts - such as active structure - and new tools - such as combined structure and control optimization algorithm - and their verification in ground and possibly flight test. A focus mission spacecraft was designed based upon a space interferometer and is the basis for design of the ground test article. The ground test bed objectives include verification of the spacecraft design concepts, the active structure elements and certain design tools such as the new combined structures and controls optimization tool. In anticipation of CSI technology flight experiments, the test bed control electronics must emulate the computation capacity and control architectures of space qualifiable systems as well as the command and control networks that will be used to connect investigators with the flight experiment hardware. The Test Bed facility electronics were functionally partitioned into three units: a laboratory data acquisition system for structural parameter identification and performance verification; an experiment supervisory computer to oversee the experiment, monitor the environmental parameters and perform data logging; and a multilevel real-time control computing system. The design of the Test Bed electronics is presented along with hardware and software component descriptions. The system should break new ground in experimental control electronics and is of interest to anyone working in the verification of control concepts for large structures.

Artist Concept of MAVEN Imaging Ultraviolet Spectrograph at Work

NASA Image and Video Library

2014-11-07

This artist concept depicts the Imaging Ultraviolet Spectrograph IUVS on NASA MAVEN spacecraft scanning the upper atmosphere of Mars. IUVS uses limb scans to map the chemical makeup and vertical structure across Mars upper atmosphere.

Liquid metal porous matrix sliding electrical contact: A concept

NASA Technical Reports Server (NTRS)

Ferguson, H.

1973-01-01

Concept utilizes porous metal or nonmetal matrix containing liquid metal in porous structure and confines liquid metal to contact area between rotor and brush by capillary forces. System may also be used to lubricate bearing systems.