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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

Connecting node and method for constructing a connecting node

A connecting node comprises a polyhedral structure comprising a plurality of panels joined together at its side edges to form a spherical approximation, wherein at least one of the plurality of panels comprises a faceted surface being constructed with a passage for integrating with one of a plurality of elements comprising a docking port, a hatch, and a window that is attached to the connecting node. A method for manufacturing a connecting node comprises the steps of providing a plurality of panels, connecting the plurality of panels to form a spherical approximation, wherein each edge of each panel of the plurality is joined to another edge of another panel, and constructing at least one of the plurality of panels to include a passage for integrating at least one of a plurality of elements that may be attached to the connecting node.

Johnson, Christopher J.↗
NASA NTRS1992

Power connect safety and connection interlock

A power connect safety and connection interlock system is shown for use with inverters and other DC loads (16) which include capacitor filter banks (14) at their DC inputs. A safety circuit (20) operates a spring (26) biased, solenoid (22) driven mechanical connection interference (24) which prevents mating and therefore electrical connection between the power contactor halves (11, 13) of the main power contacts (12) until the capacitor bank is safely precharged through auxiliary contacts (18). When the DC load (16) is shut down, the capacitor bank (14) is automatically discharged through a discharging power resistor (66) by a MOSFET transistor (60) through a discharging power resistor (66) only when both the main power contacts and auxiliary contacts are disconnected.

Rippel, Wally E.↗
NASA NTRS2003

Development of inner ear afferent connections: forming primary neurons and connecting them to the developing sensory epithelia

The molecular and cellular origin of the primary neurons of the inner ear, the vestibular and spiral neurons, is reviewed including how they connect to the specific sensory epithelia and what the molecular nature of their survival is. Primary neurons of the ear depend on a single basic Helix-Loop-Helix (bHLH) protein for their formation, neurogenin 1 (ngn1). An immediate downstream gene is the bHLH gene neuronal differentiation (NeuroD). Targeted null mutations of ngn1 results in absence of primary neuron formation; targeted null mutation of NeuroD results in loss of almost all spiral and many vestibular neurons. NeuroD and a later expressed gene, Brn3a, play a role in pathfinding to and within sensory epithelia. The molecular nature of this pathfinding property is unknown. Reduction of hair cells in ngn1 null mutations suggests a clonal relationship with primary neurons. This relationship may play some role in specifying the identity of hair cells and the primary neurons that connect with them. Primary neuron neurites growth to sensory epithelia is initially independent of trophic factors released from developing sensory epithelia, but becomes rapidly dependent on those factors. Null mutations of specific neurotrophic factors lose distinct primary neuron populations which undergo rapid embryonic cell death.

Review↗
NASA NTRS2010

Optimal and Local Connectivity Between Neuron and Synapse Array in the Quantum Dot/Silicon Brain

This innovation is used to connect between synapse and neuron arrays using nanowire in quantum dot and metal in CMOS (complementary metal oxide semiconductor) technology to enable the density of a brain-like connection in hardware. The hardware implementation combines three technologies: 1. Quantum dot and nanowire-based compact synaptic cell (50x50 sq nm) with inherently low parasitic capacitance (hence, low dynamic power approx.l0(exp -11) watts/synapse), 2. Neuron and learning circuits implemented in 50-nm CMOS technology, to be integrated with quantum dot and nanowire synapse, and 3. 3D stacking approach to achieve the overall numbers of high density O(10(exp 12)) synapses and O(10(exp 8)) neurons in the overall system. In a 1-sq cm of quantum dot layer sitting on a 50-nm CMOS layer, innovators were able to pack a 10(exp 6)-neuron and 10(exp 10)-synapse array; however, the constraint for the connection scheme is that each neuron will receive a non-identical 10(exp 4)-synapse set, including itself, via its efficacy of the connection. This is not a fully connected system where the 100x100 synapse array only has a 100-input data bus and 100-output data bus. Due to the data bus sharing, it poses a great challenge to have a complete connected system, and its constraint within the quantum dot and silicon wafer layer. For an effective connection scheme, there are three conditions to be met: 1. Local connection. 2. The nanowire should be connected locally, not globally from which it helps to maximize the data flow by sharing the same wire space location. 3. Each synapse can have an alternate summation line if needed (this option is doable based on the simple mask creation). The 10(exp 3)x10(exp 3)-neuron array was partitioned into a 10-block, 10(exp 2)x10(exp 3)-neuron array. This building block can be completely mapped within itself (10,000 synapses to a neuron).

Duong, Tuan A.↗
NASA NTRS2015

The Effects of Long Duration Bed Rest as a Spaceflight Analogue on Resting State Sensorimotor Network Functional Connectivity and Neurocognitive Performance

Long duration spaceflight has been associated with detrimental alterations in human sensorimotor systems and neurocognitive performance. Prolonged exposure to a head-down tilt position during long duration bed rest can resemble several effects of the microgravity environment such as reduced sensory inputs, body unloading and increased cephalic fluid distribution. The question of whether microgravity affects other central nervous system functions such as brain functional connectivity and its relationship with neurocognitive performance is largely unknown, but of potential importance to the health and performance of astronauts both during and post-flight. The aims of the present study are 1) to identify changes in sensorimotor resting state functional connectivity that occur with extended bed rest exposure, and to characterize their recovery time course; 2) to evaluate how these neural changes correlate with neurocognitive performance. Resting-state functional magnetic resonance imaging (rsfMRI) data were collected from 17 male participants. The data were acquired through the NASA bed rest facility, located at the University of Texas Medical Branch (Galveston, TX). Participants remained in bed with their heads tilted down six degrees below their feet for 70 consecutive days. RsfMRI data were obtained at seven time points: 7 and 12 days before bed rest; 7, 50, and 65 days during bed rest; and 7 and 12 days after bed rest. Functional connectivity magnetic resonance imaging (fcMRI) analysis was performed to measure the connectivity of sensorimotor networks in the brain before, during, and post-bed rest. We found a decrease in left putamen connectivity with the pre- and post-central gyri from pre bed rest to the last day in bed rest. In addition, vestibular cortex connectivity with the posterior cingulate cortex decreased from pre to post bed rest. Furthermore, connectivity between cerebellar right superior posterior fissure and other cerebellar regions decreased from pre bed rest to the last day in bed rest. In contrast, connectivity within the default mode network remained stable over the course of bed rest. We also utilized a battery of behavioral measures including spatial working memory tasks and measures of functional mobility and balance. These behavioral measurements were collected before, during, and after bed rest. We will report the preliminary findings of correlations observed between brain functional connectivity and behavioral performance changes. Our results suggest that sensorimotor brain networks exhibit decoupling with extended periods of reduced usage. The findings from this study could aid in the understanding and future design of targeted countermeasures to alleviate the detrimental health and neurocognitive effects of long-duration spaceflight.

Cassady, K.↗
NASA NTRSDate not supplied

Perturbations in Brain Functional Connectivity Patterns After Waking From Slow Wave Sleep Under Different Cognitive States

Sleep inertia refers to the state of transition between sleep and wake characterized by impaired alertness, confusion, and reduced cognitive and behavioral performance. While the behavioral symptoms of sleep inertia are well described, the neurological changes that lead to this state remain elusive. Here, to understand the state of sleep inertia and the reorganization that the brain undergoes, we took a graph theoretical approach and compared the EEG derived brain connectivity patterns before sleep and after waking up while participants (n = 10) performed multiple tasks that differed in cognitive complexities. We focused on how the degree and the clustering coefficient of brain regions (EEG sensors) change immediately after participants wake up from slow wave sleep. During a psychomotor vigilance task (PVT), designed to assess vigilant attention, we find that the brain regions with strong network connectivity (degree) before sleep show a reduction in connectivity after waking. In contrast, those with low connectivity before sleep have greater connectivity after waking. The regions that undergo these changes are specific to each participant and these findings are unique to the beta frequency range, which plays a key role in sensorimotor functioning and preserving the current state of the brain. Moreover, in tasks that required inhibitory control and arithmetic reasoning, we found that only regions with weak connectivity before sleep exhibited more connections after waking, but regions with high connectivity prior to sleeping remained unchanged, highlighting task specific effects. Furthermore, we find that during the PVT, the clustering coefficient within low frequency oscillations of the brain is reduced upon waking while it remains unchanged during other tasks. These results suggest that the connections between regions that are lost after abrupt awakening can be reallocated to other regions in order to renormalize the brain. However, this response may only be evident during specific cognitive states and may be more nuanced during complex task performance.

sleep inertia↗
NASA NTRS1989

Characterization of structural connections using free and forced response test data

The accurate prediction of system dynamic response often has been limited by deficiencies in existing capabilities to characterize connections adequately. Connections between structural components often are complex mechanically, and difficult to accurately model analytically. Improved analytical models for connections are needed to improve system dynamic preditions. A procedure for identifying physical connection properties from free and forced response test data is developed, then verified utilizing a system having both a linear and nonlinear connection. Connection properties are computed in terms of physical parameters so that the physical characteristics of the connections can better be understood, in addition to providing improved input for the system model. The identification procedure is applicable to multi-degree of freedom systems, and does not require that the test data be measured directly at the connection locations.

Lawrence, Charles↗
NASA NTRS1989

Characterization of structural connections using free and forced response test data

The accurate prediction of system dynamic response often has been limited by deficiencies in existing capabilities to characterize connections adequately. Connections between structural components often are complex mechanically, and difficult to accurately model analytically. Improved analytical models for connections are needed to improve system dynamic predictions. A procedure for identifying physical connection properties from free and forced response test data is developed, then verified utilizing a system having both a linear and nonlinear connection. Connection properties are computed in terms of physical parameters so that the physical characteristics of the connections can better be understood, in addition to providing improved input for the system model. The identification procedure is applicable to multi-degree of freedom systems, and does not require that the test data be measured directly at the connection locations.

Lawrence, C.↗
NASA NTRS2000

Evaluating the Effectiveness of the 1998-1999 NASA CONNECT Program

NASA CONNECT is a standards-based, integrated mathematics, science, and technology series of 30-minute instructional distance learning (satellite and television) programs for students in grades 5-8. Each of the five programs in the 1998-1999 NASA CONNECT series included a lesson, an educator guide, a student activity or experiment, and a web-based component. In March 1999, a mail (self-reported) survey (booklet) was sent to a randomly selected sample of 1,000 NASA CONNECT registrants. A total of 401 surveys (351 usable) were received by the established cut-off date. Most survey questions employed a 5-point Likert-type response scale. Survey topics included: (1) instructional technology and teaching, (2) instructional programming and technology in the classroom, (3) the NASA CONNECT program, (4) classroom use of computer technology, and (5) demographics. About 68% of the respondents were female, about 88% identified "classroom teacher" as their present professional duty, about 75% worked in a public school, and about 67% held a master's degree or master's equivalency. Regarding NASA CONNECT, respondents reported that: (1) they used the five programs in the 1998-1999 NASA CONNECT series; (2) the stated objectives for each program were met (4.49); (3) the programs were aligned with the national mathematics, science, and technology standards (4.61); (4) program content was developmentally appropriate for grade level (4.25); and (5) the programs in the 1998-1999 NASA CONNECT series enhanced/enriched the teaching of mathematics, science, and technology (4.45).

Pinelli, Thomas E.↗
NASA NTRS2002

Evaluating the Effectiveness of the 1999-2000 NASA CONNECT Program

NASA CONNECT is a standards-based, integrated mathematics, science, and technology series of 30-minute instructional distance learning (satellite and television) programs for students in grades 6-8. Each of the five programs in the 1999-2000 NASA CONNECT series included a lesson, an educator guide, a student activity or experiment, and a web-based component. In March 2000, a mail (self-reported) survey (booklet) was sent to a randomly selected sample of 1,000 NASA CONNECT registrants. A total of 336 surveys (269 usable) were received by the established cut-off date. Most survey questions employed a 5-point Likert-type response scale. Survey topics included (1) instructional technology and teaching, (2) instructional programming and technology in the classroom, (3) the NASA CONNECT program, (4) classroom use of computer technology, and (5) demographics. About 73% of the respondents were female, about 92% identified "classroom teacher" as their present professional duty, about 90% worked in a public school, and about 62% held a master's degree or master's equivalency. Regarding NASA CONNECT, respondents reported that (1) they used the five programs in the 1999-2000 NASA CONNECT series; (2) the stated objectives for each program were met (4.54); (3) the programs were aligned with the national mathematics, science, and technology standards (4.57); (4) program content was developmentally appropriate for grade level (4.17); and (5) the programs in the 1999-2000 NASA CONNECT series enhanced/enriched the teaching of mathematics, science, and technology (4.51).

Pinelli, Thomas E.↗
NASA NTRS2007

Device and Method for Connections Made Between a Crimp Connector and Wire

An ultrasonic device and method obtains desirable crimp connections between a crimp connector and a wire, or bundle of wires, by assessing the desirability of connections made in a wire-to-wire connection and in other situations where two materials with good acoustic propagation characteristics are joined together via deformation. An embodiment of the device as a crimping tool comprises a compressing means, pulse-generating circuitry. at least one ultrasonic transmitting transducer, at least one ultrasonic receiving transducer, receiving circuitry, and a display. The user may return to a previously crimped connection and assess the desirability of the connection by compressing the device about the connection, sending an acoustic signal through the crimp, andco111paring the received signal to a signal obtained from known desirable connections.

Yost, William T.↗
NASA NTRS1982

Array processor architecture connection network

A connection network is disclosed for use between a parallel array of processors and a parallel array of memory modules for establishing non-conflicting data communications paths between requested memory modules and requesting processors. The connection network includes a plurality of switching elements interposed between the processor array and the memory modules array in an Omega networking architecture. Each switching element includes a first and a second processor side port, a first and a second memory module side port, and control logic circuitry for providing data connections between the first and second processor ports and the first and second memory module ports. The control logic circuitry includes strobe logic for examining data arriving at the first and the second processor ports to indicate when the data arriving is requesting data from a requesting processor to a requested memory module. Further, connection circuitry is associated with the strobe logic for examining requesting data arriving at the first and the second processor ports for providing a data connection therefrom to the first and the second memory module ports in response thereto when the data connection so provided does not conflict with a pre-established data connection currently in use.

Barnes, George H.↗