Intracochlear Pressure Transients During Cochlear Implant Electrode Insertion.

PubMed

Greene, Nathaniel T; Mattingly, Jameson K; Banakis Hartl, Renee M; Tollin, Daniel J; Cass, Stephen P

2016-12-01

Cochlear implant (CI) electrode insertion into the round window induces pressure transients in the cochlear fluid comparable to high-intensity sound transients. Many patients receiving a CI have some remaining functional hearing at low frequencies; thus, devices and surgical techniques have been developed to use this residual hearing. To maintain functional acoustic hearing, it is important to retain function of any hair cells and auditory nerve fibers innervating the basilar membrane; however, in a subset of patients, residual low-frequency hearing is lost after CI insertion. Here, we test the hypothesis that transient intracochlear pressure spikes are generated during CI electrode insertion, which could cause damage and compromise residual hearing. Human cadaveric temporal bones were prepared with an extended facial recess. Pressures in the scala vestibuli and tympani were measured with fiber-optic pressure sensors inserted into the cochlea near the oval and round windows, whereas CI electrodes (five styles from two manufacturers) were inserted into the cochlea via a round window approach. Pressures in the scala tympani tended to be larger in magnitude than pressures in the scala vestibuli, consistent with electrode insertion into the scala tympani. CI electrode insertion produced a range of pressure transients in the cochlea that could occur alone or as part of a train of spikes with equivalent peak sound pressure levels in excess of 170 dB sound pressure level. Instances of pressure transients varied with electrode styles. Results suggest electrode design, insertion mechanism, and surgical technique affect the magnitude and rate of intracochlear pressure transients during CI electrode insertion. Pressure transients showed intensities similar to those elicited by high-level sounds and thus could cause damage to the basilar membrane and/or hair cells.

Intracochlear pressure transients during cochlear implant electrode insertion

PubMed Central

Greene, Nathaniel T.; Mattingly, Jameson K.; Banakis Hartl, Renee M.; Tollin, Daniel J.; Cass, Stephen P.

2016-01-01

Hypothesis Cochlear implant (CI) electrode insertion into the round window induces pressure transients in the cochlear fluid comparable to high intensity sound transients. Background Many patients receiving a CI have some remaining functional hearing at low frequencies, thus devices and surgical techniques have been developed to utilize this residual hearing. To maintain functional acoustic hearing, it is important to retain function of any hair cells and auditory nerve fibers innervating the basilar membrane; however, in a subset of patients, residual low frequency hearing is lost following CI insertion. Here, we test the hypothesis that transient intracochlear pressure spikes are generated during CI electrode insertion, which could cause damage and compromise residual hearing. Methods Human cadaveric temporal bones were prepared with an extended facial recess. Pressures in the scala vestibuli (PSV) and tympani (PST) were measured with fiber-optic pressure sensors inserted into the cochlea near the oval and round windows while CI electrodes (five styles from two manufacturers) were inserted into the cochlea via a round window approach. Results PST tended to be larger in magnitude than PSV, consistent with electrode insertion into the scala tympani. CI electrode insertion produced a range of pressure transients in the cochlea that could occur alone or as part of a train of spikes with equivalent peak sound pressure levels in excess of 170dB SPL. Instances of pressure transients varied with electrode styles. Conclusions Results suggest electrode design, insertion mechanism, and surgical technique affect the magnitude and rate of intracochlear pressure transients during CI electrode insertion. Pressure transients showed intensities similar to those elicited by high level sounds and thus could cause damage to the basilar membrane and/or hair cells. PMID:27753703

Semantic memory and frontal executive function during transient global amnesia.

PubMed

Hodges, J R

1994-05-01

To assess semantic memory and frontal executive function, two patients underwent neuropsychological testing during transient global amnesia (TGA) and after an interval of 6-8 weeks. In spite of a profound deficit in anterograde verbal and non-verbal memory, semantic memory was normal, as judged by category fluency measures, picture naming, and picture-word and picture-picture matching, and reading ability was normal. Similarly, there were no deficits on a number of tests known to be sensitive to frontal executive dysfunction. A hexamethylpropyleneamine-oxime (HMPAO) single photon emission CT (SPECT) scan, obtained on one patient 24 hours post-TGA, showed focal left temporal lobe hypoperfusion which had resolved three months later. The observed dissociation between episodic and semantic memory is discussed in the light of contemporary cognitive theories of memory organisation.

Angular response calibration of the burst and transient source experiment

NASA Technical Reports Server (NTRS)

Lestrade, John Patrick

1988-01-01

The Gamma Ray Observatory includes four experiments designed to observe the gamma-ray universe. Laboratory measurements to test the response the Burst and Transient Source Experiment (BATSE) modules to gamma-ray sources that are non-axial were recently completed. The results of these observations are necessary for the correct interpretation of BATSE data obtained after it is put in Earth orbit. The launch is planned for March, 1900. Preliminary analyses of these test data show the presence of a radial dependence to the detector's light collection efficiency. It is proposed to evaluate the importance of this radial response, analyze future experimental data to derive the actual functional dependence on radius, and calculate the net effect on the output spectrum as a function of the angle of incidence.

A point implicit time integration technique for slow transient flow problems

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

Kadioglu, Samet Y.; Berry, Ray A.; Martineau, Richard C.

2015-05-01

We introduce a point implicit time integration technique for slow transient flow problems. The method treats the solution variables of interest (that can be located at cell centers, cell edges, or cell nodes) implicitly and the rest of the information related to same or other variables are handled explicitly. The method does not require implicit iteration; instead it time advances the solutions in a similar spirit to explicit methods, except it involves a few additional function(s) evaluation steps. Moreover, the method is unconditionally stable, as a fully implicit method would be. This new approach exhibits the simplicity of implementation ofmore » explicit methods and the stability of implicit methods. It is specifically designed for slow transient flow problems of long duration wherein one would like to perform time integrations with very large time steps. Because the method can be time inaccurate for fast transient problems, particularly with larger time steps, an appropriate solution strategy for a problem that evolves from a fast to a slow transient would be to integrate the fast transient with an explicit or semi-implicit technique and then switch to this point implicit method as soon as the time variation slows sufficiently. We have solved several test problems that result from scalar or systems of flow equations. Our findings indicate the new method can integrate slow transient problems very efficiently; and its implementation is very robust.« less

The use of transmission line modelling to test the effectiveness of I-kaz as autonomous selection of intrinsic mode function

NASA Astrophysics Data System (ADS)

Yusop, Hanafi M.; Ghazali, M. F.; Yusof, M. F. M.; PiRemli, M. A.; Karollah, B.; Rusman

2017-10-01

Pressure transient signal occurred due to sudden changes in fluid propagation filled in pipelines system, which is caused by rapid pressure and flow fluctuation in a system, such as closing and opening valve rapidly. The application of Hilbert-Huang Transform (HHT) as the method to analyse the pressure transient signal utilised in this research. However, this method has the difficulty in selecting the suitable IMF for the further post-processing, which is Hilbert Transform (HT). This paper proposed the implementation of Integrated Kurtosis-based Algorithm for z-filter Technique (I-kaz) to kurtosis ratio (I-kaz-Kurtosis) for that allows automatic selection of intrinsic mode function (IMF) that’s should be used. This work demonstrated the synthetic pressure transient signal generates using transmission line modelling (TLM) in order to test the effectiveness of I-kaz as the autonomous selection of intrinsic mode function (IMF). A straight fluid network was designed using TLM fixing with higher resistance at some point act as a leak and connecting to the pipe feature (junction, pipefitting or blockage). The analysis results using I-kaz-kurtosis ratio revealed that the method can be utilised as an automatic selection of intrinsic mode function (IMF) although the noise level ratio of the signal is lower. I-kaz-kurtosis ratio is recommended and advised to be implemented as automatic selection of intrinsic mode function (IMF) through HHT analysis.

Association Between Transient Newborn Hypoglycemia and Fourth-Grade Achievement Test Proficiency: A Population-Based Study.

PubMed

Kaiser, Jeffrey R; Bai, Shasha; Gibson, Neal; Holland, Greg; Lin, Tsai Mei; Swearingen, Christopher J; Mehl, Jennifer K; ElHassan, Nahed O

2015-10-01

Prolonged neonatal hypoglycemia is associated with poor long-term neurocognitive function. However, little is known about an association between early transient newborn hypoglycemia and academic achievement. To determine if early (within the first 3 hours of life) transient hypoglycemia (a single initial low glucose concentration, followed by a second value above a cutoff) is associated with subsequent poor academic performance. A retrospective population-based cohort study of all infants born between January 1, 1998, and December 31, 1998, at the University of Arkansas for Medical Sciences who had at least 1 recorded glucose concentration (a universal newborn glucose screening policy was in effect) was conducted. Medical record data from newborns with normoglycemia or transient hypoglycemia were matched with their student achievement test scores in 2008 from the Arkansas Department of Education and anonymized. Logistic regression models were developed to evaluate the association between transient hypoglycemia and school-age achievement test proficiency based on perinatal factors. Common hypoglycemia cutoffs of a glucose level less than 35 mg/dL (primary) and less than 40 and 45 mg/dL (secondary) were investigated. All 1943 normoglycemic and transiently hypoglycemic infants (23-42 weeks' gestation) were eligible for inclusion in the study. Infants with prolonged hypoglycemia, congenital anomalies, or chromosomal abnormalities were excluded from the study. Hypoglycemia as a newborn. The primary outcome was proficiency on fourth-grade literacy and mathematics achievement tests at age 10 years. We hypothesized a priori that newborns with early transient hypoglycemia would be less proficient on fourth-grade achievement tests compared with normoglycemic newborns. Perinatal data were matched with fourth-grade achievement test scores in 1395 newborn-student pairs (71.8%). Transient hypoglycemia (glucose level <35, <40, and <45 mg/dL) was observed in 6.4% (89 of 1395), 10.3% (143 of 1395), and 19.3% (269 of 1395) of newborns, respectively. After controlling for gestational age group, race, sex, multifetal gestation, insurance status, maternal educational level and socioeconomic status, and gravidity, transient hypoglycemia was associated with decreased probability of proficiency on literacy and mathematics fourth-grade achievement tests. For the 3 hypoglycemia cutoffs, the adjusted odds ratios (95% CIs) for literacy were 0.49 (0.28-0.83), 0.43 (0.28-0.67), and 0.62 (0.45-0.85), respectively, and the adjusted odds ratios (95% CIs) for mathematics were 0.49 (0.29-0.82), 0.51 (0.34-0.78), and 0.78 (0.57-1.08), respectively. Early transient newborn hypoglycemia was associated with lower achievement test scores at age 10 years. Given that our findings are serious and contrary to expert opinion, the results need to be validated in other populations before universal newborn glucose screening should be adopted.

Natural History of Thyroid Function in Adults with Down Syndrome--10-Year Follow-Up Study

ERIC Educational Resources Information Center

Prasher, V.; Gomez, G.

2007-01-01

Background: The natural history of thyroid function in adults with Down syndrome (DS) is unknown. Method: This study investigated annual thyroid function tests in 200 adults with DS over a 10-year period. Results: Transient and persistent thyroid dysfunction was common. The 5- and 10-year incidence of definite hypothyroidism was 0.9%-1.64% and…

Phenomenological model for transient deformation based on state variables

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

Jackson, M S; Cho, C W; Alexopoulos, P

The state variable theory of Hart, while providing a unified description of plasticity-dominated deformation, exhibits deficiencies when it is applied to transient deformation phenomena at stresses below yield. It appears that the description of stored anelastic strain is oversimplified. Consideration of a simple physical picture based on continuum dislocation pileups suggests that the neglect of weak barriers to dislocation motion is the source of these inadequacies. An appropriately modified description incorporating such barriers then allows the construction of a macroscopic model including transient effects. Although the flow relations for the microplastic element required in the new theory are not known,more » tentative assignments may be made for such functions. The model then exhibits qualitatively correct behavior when tensile, loading-unloading, reverse loading, and load relaxation tests are simulated. Experimental procedures are described for determining the unknown parameters and functions in the new model.« less

40 CFR 86.1333-2010 - Transient test cycle generation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Transient test cycle generation. 86... (CONTINUED) Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate Exhaust Test Procedures § 86.1333-2010 Transient test cycle generation. (a) Generating transient test...

Transient pressure analysis of fractured well in bi-zonal gas reservoirs

NASA Astrophysics Data System (ADS)

Zhao, Yu-Long; Zhang, Lie-Hui; Liu, Yong-hui; Hu, Shu-Yong; Liu, Qi-Guo

2015-05-01

For hydraulic fractured well, how to evaluate the properties of fracture and formation are always tough jobs and it is very complex to use the conventional method to do that, especially for partially penetrating fractured well. Although the source function is a very powerful tool to analyze the transient pressure for complex structure well, the corresponding reports on gas reservoir are rare. In this paper, the continuous point source functions in anisotropic reservoirs are derived on the basis of source function theory, Laplace transform method and Duhamel principle. Application of construction method, the continuous point source functions in bi-zonal gas reservoir with closed upper and lower boundaries are obtained. Sequentially, the physical models and transient pressure solutions are developed for fully and partially penetrating fractured vertical wells in this reservoir. Type curves of dimensionless pseudo-pressure and its derivative as function of dimensionless time are plotted as well by numerical inversion algorithm, and the flow periods and sensitive factors are also analyzed. The source functions and solutions of fractured well have both theoretical and practical application in well test interpretation for such gas reservoirs, especial for the well with stimulated reservoir volume around the well in unconventional gas reservoir by massive hydraulic fracturing which always can be described with the composite model.

Lightning induced currents in aircraft wiring using low level injection techniques

NASA Technical Reports Server (NTRS)

Stevens, E. G.; Jordan, D. T.

1991-01-01

Various techniques were studied to predict the transient current induced into aircraft wiring bundles as a result of an aircraft lightning strike. A series of aircraft measurements were carried out together with a theoretical analysis using computer modeling. These tests were applied to various aircraft and also to specially constructed cylinders installed within coaxial return conductor systems. Low level swept frequency CW (carrier waves), low level transient and high level transient injection tests were applied to the aircraft and cylinders. Measurements were made to determine the transfer function between the aircraft drive current and the resulting skin currents and currents induced on the internal wiring. The full threat lightning induced transient currents were extrapolated from the low level data using Fourier transform techniques. The aircraft and cylinders used were constructed from both metallic and CFC (carbon fiber composite) materials. The results show the pulse stretching phenomenon which occurs for CFC materials due to the diffusion of the lightning current through carbon fiber materials. Transmission Line Matrix modeling techniques were used to compare theoretical and measured currents.

Extended probit mortality model for zooplankton against transient change of PCO(2).

PubMed

Sato, Toru; Watanabe, Yuji; Toyota, Koji; Ishizaka, Joji

2005-09-01

The direct injection of CO(2) in the deep ocean is a promising way to mitigate global warming. One of the uncertainties in this method, however, is its impact on marine organisms in the near field. Since the concentration of CO(2), which organisms experience in the ocean, changes with time, it is required to develop a biological impact model for the organisms against the unsteady change of CO(2) concentration. In general, the LC(50) concept is widely applied for testing a toxic agent for the acute mortality. Here, we regard the probit-transformed mortality as a linear function not only of the concentration of CO(2) but also of exposure time. A simple mathematical transform of the function gives a damage-accumulation mortality model for zooplankton. In this article, this model was validated by the mortality test of Metamphiascopsis hirsutus against the transient change of CO(2) concentration.

Selective Vulnerability of Specific Retinal Ganglion Cell Types and Synapses after Transient Ocular Hypertension.

PubMed

Ou, Yvonne; Jo, Rebecca E; Ullian, Erik M; Wong, Rachel O L; Della Santina, Luca

2016-08-31

Key issues concerning ganglion cell type-specific loss and synaptic changes in animal models of experimental glaucoma remain highly debated. Importantly, changes in the structure and function of various RGC types that occur early, within 14 d after acute, transient intraocular pressure elevation, have not been previously assessed. Using biolistic transfection of individual RGCs and multielectrode array recordings to measure light responses in mice, we examined the effects of laser-induced ocular hypertension on the structure and function of a subset of RGCs. Among the α-like RGCs studied, αOFF-transient RGCs exhibited higher rates of cell death, with corresponding reductions in dendritic area, dendritic complexity, and synapse density. Functionally, OFF-transient RGCs displayed decreases in spontaneous activity and receptive field size. In contrast, neither αOFF-sustained nor αON-sustained RGCs displayed decreases in light responses, although they did exhibit a decrease in excitatory postsynaptic sites, suggesting that synapse loss may be one of the earliest signs of degeneration. Interestingly, presynaptic ribbon density decreased to a greater degree in the OFF sublamina of the inner plexiform layer, corroborating the hypothesis that RGCs with dendrites stratifying in the OFF sublamina may be damaged early. Indeed, OFF arbors of ON-OFF RGCs lose complexity more rapidly than ON arbors. Our results reveal type-specific differences in RGC responses to injury with a selective vulnerability of αOFF-transient RGCs, and furthermore, an increased susceptibility of synapses in the OFF sublamina. The selective vulnerability of specific RGC types offers new avenues for the design of more sensitive functional tests and targeted neuroprotection. Conflicting reports regarding the selective vulnerability of specific retinal ganglion cell (RGC) types in glaucoma exist. We examine, for the first time, the effects of transient intraocular pressure elevation on the structure and function of various RGC types. Among the α-like RGCs studied, αOFF-transient RGCs are the most vulnerable to transient transient intraocular pressure elevation as measured by rates of cell death, morphologic alterations in dendrites and synapses, and physiological dysfunction. Specifically, we found that presynaptic ribbon density decreased to a greater degree in the OFF sublamina of the inner plexiform layer. Our results suggest selective vulnerability both of specific types of RGCs and of specific inner plexiform layer sublaminae, opening new avenues for identifying novel diagnostic and treatment targets in glaucoma. Copyright © 2016 the authors 0270-6474/16/369240-13$15.00/0.

Novel role of transient receptor potential vanilloid 2 in the regulation of cardiac performance

PubMed Central

Lasko, Valerie M.; Koch, Sheryl E.; Singh, Vivek P.; Carreira, Vinicius; Robbins, Nathan; Patel, Amit R.; Jiang, Min; Bidwell, Philip; Kranias, Evangelia G.; Jones, W. Keith; Lorenz, John N.

2013-01-01

Transient receptor potential cation channels have been implicated in the regulation of cardiovascular function, but only recently has our laboratory described the vanilloid-2 subtype (TRPV2) in the cardiomyocyte, though its exact mechanism of action has not yet been established. This study tests the hypothesis that TRPV2 plays an important role in regulating myocyte contractility under physiological conditions. Therefore, we measured cardiac and vascular function in wild-type and TRPV2−/− mice in vitro and in vivo and found that TRPV2 deletion resulted in a decrease in basal systolic and diastolic function without affecting loading conditions or vascular tone. TRPV2 stimulation with probenecid, a relatively selective TRPV2 agonist, caused an increase in both inotropy and lusitropy in wild-type mice that was blunted in TRPV2−/− mice. We examined the mechanism of TRPV2 inotropy/lusitropy in isolated myocytes and found that it modulates Ca2+ transients and sarcoplasmic reticulum Ca2+ loading. We show that the activity of this channel is necessary for normal cardiac function and that there is increased contractility in response to agonism of TRPV2 with probenecid. PMID:24322617

A shifted repertoire of endocannabinoid genes in the zebrafish (Danio rerio).

PubMed

McPartland, J M; Glass, Michelle; Matias, Isabel; Norris, Ryan W; Kilpatrick, C William

2007-05-01

The zebrafish has served as a model organism for developmental biology. Sequencing its genome has expanded zebrafish research into physiology and drug-development testing. Several cannabinoid pharmaceuticals are in development, but expression of endocannabinoid receptors and enzymes remains unknown in this species. We conducted a bioinformatics analysis of the zebrafish genome using 17 human endocannabinoid genes as a reference set. Putative zebrafish orthologs were identified in filtered BLAST searches as reciprocal best hits. Orthology was confirmed by three in silico methods: phylogenetic testing, synteny analysis, and functional mapping. Zebrafish expressed orthologs of cannabinoid receptor 1, transient receptor potential channel vanilloid receptor 4, GPR55 receptor, fatty acid amide hydrolase 1, monoacylglycerol lipase, NAPE-selective phospholipase D, abhydrolase domain-containing protein 4, and diacylglycerol lipase alpha and beta; and paired paralogs of cannabinoid receptor 2, fatty acid amide hydrolase 2, peroxisome proliferator-activated receptor alpha, prostaglandin-endoperoxide synthase 2, and transient receptor potential cation channel subtype A1. Functional mapping suggested the orthologs of transient receptor potential vanilloid receptor 1 and peroxisome proliferator-activated receptor gamma lack specific amino acids critical for cannabinoid ligand binding. No orthologs of N-acylethanolamine acid amidase or protein tyrosine phosphatase, non-receptor type 22 were identified. In conclusion, the zebrafish genome expresses a shifted repertoire of endocannabinoid genes. In vitro analyses are warranted before using zebrafish for cannabinoid development testing.

TREAT Transient Analysis Benchmarking for the HEU Core

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

Kontogeorgakos, D. C.; Connaway, H. M.; Wright, A. E.

2014-05-01

This work was performed to support the feasibility study on the potential conversion of the Transient Reactor Test Facility (TREAT) at Idaho National Laboratory from the use of high enriched uranium (HEU) fuel to the use of low enriched uranium (LEU) fuel. The analyses were performed by the GTRI Reactor Conversion staff at the Argonne National Laboratory (ANL). The objective of this study was to benchmark the transient calculations against temperature-limited transients performed in the final operating HEU TREAT core configuration. The MCNP code was used to evaluate steady-state neutronics behavior, and the point kinetics code TREKIN was used tomore » determine core power and energy during transients. The first part of the benchmarking process was to calculate with MCNP all the neutronic parameters required by TREKIN to simulate the transients: the transient rod-bank worth, the prompt neutron generation lifetime, the temperature reactivity feedback as a function of total core energy, and the core-average temperature and peak temperature as a functions of total core energy. The results of these calculations were compared against measurements or against reported values as documented in the available TREAT reports. The heating of the fuel was simulated as an adiabatic process. The reported values were extracted from ANL reports, intra-laboratory memos and experiment logsheets and in some cases it was not clear if the values were based on measurements, on calculations or a combination of both. Therefore, it was decided to use the term “reported” values when referring to such data. The methods and results from the HEU core transient analyses will be used for the potential LEU core configurations to predict the converted (LEU) core’s performance.« less

40 CFR 86.1333-90 - Transient test cycle generation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Transient test cycle generation. 86...) Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate Exhaust Test Procedures § 86.1333-90 Transient test cycle generation. (a) The heavy-duty transient engine cycles for Otto...

Efficient geostatistical inversion of transient groundwater flow using preconditioned nonlinear conjugate gradients

NASA Astrophysics Data System (ADS)

Klein, Ole; Cirpka, Olaf A.; Bastian, Peter; Ippisch, Olaf

2017-04-01

In the geostatistical inverse problem of subsurface hydrology, continuous hydraulic parameter fields, in most cases hydraulic conductivity, are estimated from measurements of dependent variables, such as hydraulic heads, under the assumption that the parameter fields are autocorrelated random space functions. Upon discretization, the continuous fields become large parameter vectors with O (104 -107) elements. While cokriging-like inversion methods have been shown to be efficient for highly resolved parameter fields when the number of measurements is small, they require the calculation of the sensitivity of each measurement with respect to all parameters, which may become prohibitive with large sets of measured data such as those arising from transient groundwater flow. We present a Preconditioned Conjugate Gradient method for the geostatistical inverse problem, in which a single adjoint equation needs to be solved to obtain the gradient of the objective function. Using the autocovariance matrix of the parameters as preconditioning matrix, expensive multiplications with its inverse can be avoided, and the number of iterations is significantly reduced. We use a randomized spectral decomposition of the posterior covariance matrix of the parameters to perform a linearized uncertainty quantification of the parameter estimate. The feasibility of the method is tested by virtual examples of head observations in steady-state and transient groundwater flow. These synthetic tests demonstrate that transient data can reduce both parameter uncertainty and time spent conducting experiments, while the presented methods are able to handle the resulting large number of measurements.

Calibration and testing of selected portable flowmeters for use on large irrigation systems

USGS Publications Warehouse

Luckey, Richard R.; Heimes, Frederick J.; Gaggiani, Neville G.

1980-01-01

Existing methods for measuring discharge of irrigation systems in the High Plains region are not suitable to provide the pumpage data required by the High Plains Regional Aquifer System Analysis. Three portable flowmeters that might be suitable for obtaining fast and accurate discharge measure-ments on large irrigation systems were tested during 1979 under both laboratory and field conditions: propeller type gated-pipe meter, a Doppler meter, and a transient-time meter.The gated-pipe meter was found to be difficult to use and sensitive to particulate matter in the fluid. The Doppler meter, while easy to use, would not function suitably on steel pipe 6 inches or larger in diameter, or on aluminum pipe larger than 8 inches in diameter. The transient-time meter was more difficult to use than the other two meters; however, this instrument provided a high degree of accuracy and reliability under a variety of conditions. Of the three meters tested, only the transient-time meter was found to be suitable for providing reliable discharge measurements on the variety of irrigation systems used in the High Plains region.

Steady-state pattern electroretinogram and short-duration transient visual evoked potentials in glaucomatous and healthy eyes.

PubMed

Amarasekera, Dilru C; Resende, Arthur F; Waisbourd, Michael; Puri, Sanjeev; Moster, Marlene R; Hark, Lisa A; Katz, L Jay; Fudemberg, Scott J; Mantravadi, Anand V

2018-01-01

This study evaluates two rapid electrophysiological glaucoma diagnostic tests that may add a functional perspective to glaucoma diagnosis. This study aimed to determine the ability of two office-based electrophysiological diagnostic tests, steady-state pattern electroretinogram and short-duration transient visual evoked potentials, to discern between glaucomatous and healthy eyes. This is a cross-sectional study in a hospital setting. Forty-one patients with glaucoma and 41 healthy volunteers participated in the study. Steady-state pattern electroretinogram and short-duration transient visual evoked potential testing was conducted in glaucomatous and healthy eyes. A 64-bar-size stimulus with both a low-contrast and high-contrast setting was used to compare steady-state pattern electroretinogram parameters in both groups. A low-contrast and high-contrast checkerboard stimulus was used to measure short-duration transient visual evoked potential parameters in both groups. Steady-state pattern electroretinogram parameters compared were MagnitudeD, MagnitudeD/Magnitude ratio, and the signal-to-noise ratio. Short-duration transient visual evoked potential parameters compared were amplitude and latency. MagnitudeD was significantly lower in glaucoma patients when using a low-contrast (P = 0.001) and high-contrast (P < 0.001) 64-bar-size steady-state pattern electroretinogram stimulus. MagnitudeD/Magnitude ratio and SNR were significantly lower in the glaucoma group when using a high-contrast 64-bar-size stimulus (P < 0.001 and P = 0.010, respectively). Short-duration transient visual evoked potential amplitude and latency were not significantly different between the two groups. Steady-state pattern electroretinogram was effectively able to discern between glaucomatous and healthy eyes. Steady-state pattern electroretinogram may thus have a role as a clinically useful electrophysiological diagnostic tool. © 2017 Royal Australian and New Zealand College of Ophthalmologists.

Particle bombardment - mediated gene transfer and GFP transient expression in Seteria viridis.

PubMed

Mookkan, Muruganantham

2018-04-03

Setaria viridis is one of the most important model grasses in studying monocot plant biology. Transient gene expression study is a very important tool in plant biotechnology, functional genomics, and CRISPR-Cas9 genome editing technology via particle bombardment. In this study, a particle bombardment-mediated protocol was developed to introduce DNA into Setaria viridis in vitro leaf explants. In addition, physical and biological parameters, such as helium pressure, distance from stopping screen to the target tissues, DNA concentration, and number of bombardments, were tested and optimized. Optimum concentration of transient GFP expression was achieved using 1.5 ug plasmid DNA with 0.6 mm gold particles and 6 cm bombardment distance, using 1,100 psi. Doubling the bombardment instances provides the maximum number of foci of transient GFP expression. This simple protocol will be helpful for genomics studies in the S. viridis monocot model.

A simple, stable, and accurate linear tetrahedral finite element for transient, nearly, and fully incompressible solid dynamics: A dynamic variational multiscale approach [A simple, stable, and accurate tetrahedral finite element for transient, nearly incompressible, linear and nonlinear elasticity: A dynamic variational multiscale approach

DOE PAGES

Scovazzi, Guglielmo; Carnes, Brian; Zeng, Xianyi; ...

2015-11-12

Here, we propose a new approach for the stabilization of linear tetrahedral finite elements in the case of nearly incompressible transient solid dynamics computations. Our method is based on a mixed formulation, in which the momentum equation is complemented by a rate equation for the evolution of the pressure field, approximated with piece-wise linear, continuous finite element functions. The pressure equation is stabilized to prevent spurious pressure oscillations in computations. Incidentally, it is also shown that many stabilized methods previously developed for the static case do not generalize easily to transient dynamics. Extensive tests in the context of linear andmore » nonlinear elasticity are used to corroborate the claim that the proposed method is robust, stable, and accurate.« less

A simple, stable, and accurate linear tetrahedral finite element for transient, nearly, and fully incompressible solid dynamics: A dynamic variational multiscale approach [A simple, stable, and accurate tetrahedral finite element for transient, nearly incompressible, linear and nonlinear elasticity: A dynamic variational multiscale approach

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

Scovazzi, Guglielmo; Carnes, Brian; Zeng, Xianyi

Here, we propose a new approach for the stabilization of linear tetrahedral finite elements in the case of nearly incompressible transient solid dynamics computations. Our method is based on a mixed formulation, in which the momentum equation is complemented by a rate equation for the evolution of the pressure field, approximated with piece-wise linear, continuous finite element functions. The pressure equation is stabilized to prevent spurious pressure oscillations in computations. Incidentally, it is also shown that many stabilized methods previously developed for the static case do not generalize easily to transient dynamics. Extensive tests in the context of linear andmore » nonlinear elasticity are used to corroborate the claim that the proposed method is robust, stable, and accurate.« less

Acute hyperglycemia produces transient improvement in glucose transporter type 1 deficiency.

PubMed

Akman, Cigdem I; Engelstad, Kristin; Hinton, Veronica J; Ullner, Paivi; Koenigsberger, Dorcas; Leary, Linda; Wang, Dong; De Vivo, Darryl C

2010-01-01

Glucose transporter type 1 deficiency syndrome (Glut1-DS) is characterized clinically by acquired microcephaly, infantile-onset seizures, psychomotor retardation, choreoathetosis, dystonia, and ataxia. The laboratory signature is hypoglycorrhachia. The 5-hour oral glucose tolerance test (OGTT) was performed to assess cerebral function and systemic carbohydrate homeostasis during acute hyperglycemia, in the knowledge that GLUT1 is constitutively expressed ubiquitously and upregulated in the brain. Thirteen Glut1-DS patients completed a 5-hour OGTT. Six patients had prolonged electroencephalographic (EEG)/video monitoring, 10 patients had plasma glucose and serum insulin measurements, and 5 patients had repeated measures of attention, memory, fine motor coordination, and well-being. All patients had a full neuropsychological battery prior to OGTT. The glycemic profile and insulin response during the OGTT were normal. Following the glucose load, transient improvement of clinical seizures and EEG findings were observed, with the most significant improvement beginning within the first 30 minutes and continuing for 180 minutes. Thereafter, clinical seizures returned, and EEG findings worsened. Additionally, transient improvement in attention, fine motor coordination, and reported well-being were observed without any change in memory performance. This study documents transient neurological improvement in Glut1-DS patients following acute hyperglycemia, associated with improved fine motor coordination and attention. Also, systemic carbohydrate homeostasis was normal, despite GLUT1 haploinsufficiency, confirming the specific role of GLUT1 as the transporter of metabolic fuel across the blood-brain barrier. The transient improvement in brain function underscores the rate-limiting role of glucose transport and the critical minute-to-minute dependence of cerebral function on fuel availability for energy metabolism.

Conduction aphasia as a function of the dominant posterior perisylvian cortex. Report of two cases.

PubMed

Quigg, Mark; Geldmacher, David S; Elias, W Jeff

2006-05-01

Assessment of eloquent functions during brain mapping usually relies on testing reading, speech, and comprehension to uncover transient deficits during electrical stimulation. These tests stem from findings predicted by the Geschwind-Wernicke hypothesis of receptive and expressive cortices connected by white matter tracts. Later work, however, has emphasized cortical mechanisms of language function. The authors report two cases that demonstrate that conduction aphasia is cortically mediated and can be inadequately assessed if not specifically evaluated during brain mapping. To determine the distribution of language on the dominant cortex, electrical cortical stimulation was performed in two cases by using implanted subdural electrodes during brain mapping before epilepsy surgery. A transient isolated deficit in repetition of language was reported during stimulation of the posterior portion of the dominant superior temporal gyrus in one patient and during stimulation of the supramarginal gyrus in the other patient. These cases demonstrate a localization of language repetition to the posterior perisylvian cortex. Brain mapping of this region should include assessment of verbal repetition to avoid potential deficits resembling conduction aphasia.

Evaluation of cochlear involvement by transient evoked otoacoustic emission test in children with Crimean-Congo hemorrhagic fever.

PubMed

Uysal, İsmail Önder; Kaya, Ali; Güven, Ahmet Sami; Altuntaş, Emine Elif; Müderris, Suphi

2011-06-01

The aim of this study was to investigate cochlear involvement in child patients with Crimean-Congo hemorrhagic fever (CCHF) disease. Twenty-eight CCHF disease patients (56 ears) and 26 sex- and age-matched healthy control subjects (52 ears) were included in the study. Pure-tone audiometry at frequencies 0.25, 0.5, 1, 2, 4, and 6 kHz, immittance measures including tympanometry and acoustic reflex testing, and transient evoked otoacoustic emission (TEOAE) testing were performed in the patients and controls. The proportion with a result of 'fail' for the TEOAE test in the CCHF patients was not statistically significant from the control group (p>0.05). CCHF disease does not impair cochlear function in children. The clinical course of CCHF among children seems to be milder than in adults. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Orbital Transfer Vehicle Oxygen Turbopump Technology. Final Report, Volume 1. Design, Fabrication, and Hydrostatic Bearing Testing

DTIC Science & Technology

1990-12-01

Temperature Distance Sensors -. ...................... 188 Start Transient 4.5-7 Distance Sensor Signal as a Function of Speed...189 4.5-8 Distance Sensor Signal as a Function of Speed ......................................... 190 4.5-9 Cryogenic Operation of...Distance Sensors at 72,000 RPM ........................ 192 Steady State 4.5-10 Cryogenic Operation of Distance Sensor Through Start

Exploration of jasmonate signalling via automated and standardized transient expression assays in tobacco cells.

PubMed

De Sutter, Valerie; Vanderhaeghen, Rudy; Tilleman, Sofie; Lammertyn, Freya; Vanhoutte, Isabelle; Karimi, Mansour; Inzé, Dirk; Goossens, Alain; Hilson, Pierre

2005-12-01

Although sequence information and genome annotation are improving at an impressive pace, functional ontology is still non-existent or rudimentary for most genes. In this regard, transient expression assays are very valuable for identification of short functional segments in particular pathways, because they can be performed rapidly and at a scale unattainable in stably transformed tissues. Vectors were constructed and protocols developed for systematic transient assays in plant protoplasts. To enhance throughput and reproducibility, protoplast treatments were performed entirely by a liquid-handling robot in multiwell plates, including polyethylene glycol/Ca2+ cell transfection with plasmid mixtures, washes and lysis. All transcriptional readouts were measured using a dual firefly/Renilla luciferase assay, in which the former was controlled by a reporter promoter and the latter by the 35S CaMV promoter, which served as internal normalization standard. The automated protocols were suitable for transient assays in protoplasts prepared from cell cultures of Nicotiana tabacum Bright Yellow-2 and Arabidopsis thaliana. They were implemented in a screen to discover potential regulators of genes coding for key enzymes in nicotine biosynthesis. Two novel tobacco transcription factors were found, NtORC1 and NtJAP1, that positively regulate the putrescine N-methyltransferase (PMT) promoter. In addition, combinatorial tests showed that these two factors act synergistically to induce PMT transcriptional activity. The development and use of high-throughput plant transient expression assays are discussed.

Central circulatory hemodynamics as a function of gravitational stress

NASA Technical Reports Server (NTRS)

Latham, Rick D.; White, C. D.; Fanton, J. W.; Owens, R. W.; Barber, J. F.; Lewkowski, B. E.; Goff, O. T.

1991-01-01

This study focuses on an evaluation of the central hemodynamics in a nonhuman primate model to variations in gravitational states. The baboon, phylogenectically close to man, was chosen as the human surrogate. The study environments selected are head-down and head-up tilt in the physiology laboratory, centrifugation to test hypergravic stress, and parabolic flights to test transient acute responses to microgravity.

Laboratory investigations of the physics of steam flow in a porous medium

USGS Publications Warehouse

Herkelrath, W.N.; Moench, A.F.

1982-01-01

Experiments were carried out in the laboratory to test a theory of transient flow of pure steam in a uniform porous medium. This theory is used extensively in modeling pressure-transient behavior in vapor-dominated geothermal systems. Transient, superheated steam-flow experiments were run by bringing a cylinder of porous material to a uniform initial pressure, and then making a step increase in pressure at one end of the sample, while monitoring the pressure-transient breakthrough at the other end. It was found in experiments run at 100?, 125?, and 146?C that the time required for steam-pressure transients to propagate through an unconsolidated material containing sand, silt, and clay was 10 to 25 times longer than predicted by theory. It is hypothesized that the delay in the steam-pressure transient was caused by adsorption of steam in the porous sample. In order to account for steam adsorption, a sink term was included in the conservation of mass equation. In addition, energy transfer in the system has to be considered because latent heat is released when steam adsorption occurs, increasing the sample temperature by as much as 10?C. Finally, it was recognized that the steam pressure was a function of both the temperature and the amount of adsorption in the sample. For simplicity, this function was assumed to be in equilibrium adsorption isotherm, which was determined by experiment. By solving the modified mass and energy equations numerically, subject to the empirical adsorption isotherm relationship, excellent theoretical simulation of the experiments was achieved. The experiments support the hypothesis that adsorption of steam can strongly influence steam pressure-transient behavior in porous media; the results suggest that the modified steam-flow theory, which includes steam adsorption terms, should be used in modeling steam flow in vapor-dominated geothermal systems.

The hobo transposable element excises and has related elements in tephritid species

USDA-ARS?s Scientific Manuscript database

Function of the Drosophila melanogaster hobo transposon in tephritid species was tested in transient embryonic excision assays by scientists at the USDA Agricultural Research Service, Center for Medical Agricultural and Veterinary Entomology, Gainesville, Florida. Wild-type and mutant strains of Ana...

Transient response of sap flow to wind speed.

PubMed

Chu, Chia R; Hsieh, Cheng-I; Wu, Shen-Yuang; Phillips, Nathan G

2009-01-01

Transient responses of sap flow to step changes in wind speed were experimentally investigated in a wind tunnel. A Granier-type sap flow sensor was calibrated and tested in a cylindrical tube for analysis of its transient time response. Then the sensor was used to measure the transient response of a well-watered Pachira macrocarpa plant to wind speed variations. The transient response of sap flow was described using the resistance-capacitance model. The steady sap flow rate increased as the wind speed increased at low wind speeds. Once the wind speed exceeded 8.0 m s(-1), the steady sap flow rate did not increase further. The transpiration rate, measured gravimetrically, showed a similar trend. The response of nocturnal sap flow to wind speed variation was also measured and compared with the results in the daytime. Under the same wind speed, the steady sap flow rate was smaller than that in the daytime, indicating differences between diurnal and nocturnal hydraulic function, and incomplete stomatal closure at night. In addition, it was found that the temporal response of the Granier sensor is fast enough to resolve the transient behaviour of water flux in plant tissue.

Laboratory investigations of steam flow in a porous medium

USGS Publications Warehouse

Herkelrath, W.N.; Moench, A.F.; O'Neal, II

1983-01-01

Experiments were carried out in the laboratory to test a theory of transient flow of pure steam in a uniform porous medium. This theory is used in modeling pressure transient behavior in vapor dominated geothermal systems. Transient, superheated steam flow experiments were run by bringing a cylinder of porous material to a uniform initial pressure and then making a step increase in pressure at one end of the sample while monitoring the pressure transient breakthrough at the other end. It was found in experiments run at 100°, 125°, and 146°C that the time required for steam pressure transients to propagate through an unconsolidated material containing sand, silt, and clay was 10–25 times longer than predicted by conventional superheated steam flow theory. It is hypothesized that the delay in the steam pressure transient was caused by adsorption of steam in the porous sample. In order to account for steam adsorption, a sink term was included in the conservation of mass equation. In addition, energy transfer in the system has to be considered because latent heat is released when steam adsorption occurs, increasing the sample temperature by as much as 10°C. Finally, it was recognized that the steam pressure was a function of both the temperature and the amount of adsorption in the sample. This function was assumed to be an equilibrium adsorption isotherm, which was determined by experiment. By solving the modified mass and energy equations numerically, subject to the empirical adsorption isotherm relationship, excellent theoretical simulation of the experiments was achieved.

Features of postfailure fuel behavior in transient overpower and transient undercooled/overpower tests in the transient reactor test facility

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

Doerner, R.C.; Bauer, T.H.; Morman, J.A.

Prototypic oxide fuel was subjected to simulated, fast reactor severe accident conditions in a series of in-pile tests in the Transient Reactor Test Facility reactor. Seven experiments were performed on fresh and previously irradiated oxide fuel pins under transient overpower and transient undercooled. overpower accident conditions. For each of the tests, fuel motions were observed by the hodoscope. Hodoscope data are correlated with coolant flow, pressure, and temperature data recorded by the loop instrumentation. Data were analyzed from the onset of initial failure to a final mass distribution at the end of the test. In this paper results of thesemore » analyses are compared to pre- and posttest accident calculations and to posttest metallographic accident calculations and to posttest metallographic examinations and computed tomographic reconstructions from neutron radiographs.« less

Non-Destructive and Discriminating Identification of Illegal Drugs by Transient Absorption Spectroscopy in the Visible and Near-IR Wavelength Range

NASA Astrophysics Data System (ADS)

Sato, Chie; Furube, Akihiro; Katoh, Ryuzi; Nonaka, Hidehiko; Inoue, Hiroyuki

2008-11-01

We have tested the possibility of identifying illegal drugs by means of nanosecond transient absorption spectroscopy with a 10-ns UV-laser pulse for the excitation light and visible-to-near-IR light for the probe light. We measured the transient absorption spectra of acetonitrile solutions of d-methamphetamine, dl-3,4-methylenedioxymethamphetamine hydrochloride (MDMA), and dl-N-methyl-1-(1,3-benzodioxol-5-yl)-2-butanamine hydrochloride (MBDB), which are illegal drugs widely consumed in Japan. Transient absorption signals of these drugs were observed between 400 and 950 nm, a range in which they are transparent in the ground state. By analyzing the spectra in terms of exponential and Gaussian functions, we could identify the drugs and discriminate them from chemical substances having similar structures. We propose that transient absorption spectroscopy will be a useful, non-destructive method of inspecting for illegal drugs, especially when they are dissolved in liquids. Such a method may even be used for drugs packed in opaque materials if it is further extended to utilize intense femtosecond laser pulses.

Microprocessor tester for the treat upgrade reactor trip system

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

Lenkszus, F.R.; Bucher, R.G.

1984-01-01

The upgrading of the Transient Reactor Test (TREAT) Facility at ANL-Idaho has been designed to provide additional experimental capabilities for the study of core disruptive accident (CDA) phenomena. In addition, a programmable Automated Reactor Control System (ARCS) will permit high-power transients up to 11,000 MW having a controlled reactor period of from 15 to 0.1 sec. These modifications to the core neutronics will improve simulation of LMFBR accident conditions. Finally, a sophisticated, multiply-redundant safety system, the Reactor Trip System (RTS), will provide safe operation for both steady state and transient production operating modes. To insure that this complex safety systemmore » is functioning properly, a Dedicated Microprocessor Tester (DMT) has been implemented to perform a thorough checkout of the RTS prior to all TREAT operations.« less

Measurement of local high-level, transient surface heat flux

NASA Technical Reports Server (NTRS)

Liebert, Curt H.

1988-01-01

This study is part of a continuing investigation to develop methods for measuring local transient surface heat flux. A method is presented for simultaneous measurements of dual heat fluxes at a surface location by considering the heat flux as a separate function of heat stored and heat conducted within a heat flux gage. Surface heat flux information is obtained from transient temperature measurements taken at points within the gage. Heat flux was determined over a range of 4 to 22 MW/sq m. It was concluded that the method is feasible. Possible applications are for heat flux measurements on the turbine blade surfaces of space shuttle main engine turbopumps and on the component surfaces of rocket and advanced gas turbine engines and for testing sensors in heat flux gage calibrators.

Short- and long-term evaluation of cognitive functions after electroconvulsive therapy in a Japanese population.

PubMed

Takagi, Shunsuke; Takeuchi, Takashi; Yamamoto, Naoki; Fujita, Munehisa; Furuta, Ko; Ishikawa, Hiroyo; Motohashi, Nobutaka; Nishikawa, Toru

2018-02-01

While electroconvulsive therapy (ECT) is a well-established, safe, and effective treatment for mental illnesses, the potential for adverse effects on cognitive functions remains controversial. We aimed to evaluate multiple cognitive functions in different time periods before and after ECT in a Japanese population. A battery of five neurocognitive tests was administered to patients who underwent a course of ECT treatment at three time points: before, immediately after, and 4 weeks after ECT. A transient but significant decline in letter fluency function was observed immediately after ECT, but had recovered well by 4 weeks. We also observed a significant improvement in the trail-making task at 4 weeks after ECT. In a Japanese population, adverse effects of ECT on verbal fluency function-related and other cognitive impairments were transient. Over the longer term, we detected significant improvements in the performance of tasks that presumably reflected information processing speed and executive functions. © 2017 The Authors. Psychiatry and Clinical Neurosciences © 2017 Japanese Society of Psychiatry and Neurology.

A microprocessor tester for the treat upgrade reactor trip system

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

Lenkszus, F.R.; Bucher, R.G.

1985-02-01

The upgrading of the Transient Reactor Test (TREAT) Facility at ANL-Idaho has been designed to provide additional experimental capabilities for the study of core disruptive accident (CDA) phenomena. To improve the analytical extrapolation of test results to full-size assembly bundles, the facility upgrade will increase the maximum size of the test bundle from 7 to 37 fuel pins. By creating a core convertor zone around the test location, the neutron spectrum incident on the test assembly will be hardened and the maximum energy deposited in the sample will be increased. In addition, a programmable Automated Reactor Control System (ARCS) willmore » permit high-power transients up to 11,000 MW having a controlled reactor period of from 15 to 0.1 sec. These modifications to the core neutronics will improve simulation of LMFBR accident conditions. Finally, a sophisticated, multiply-redundant safety system, the Reactor Trip System (RTS), will provide safe operation for both steady state and transient production operating modes. To insure that this complex safety system is functioning properly, a Dedicated Microprocessor Tester (DMT) has been implemented to perform a thorough checkout of the RTS prior to all TREAT operations. A quantitative reliability analysis of the RTS shows that the unreliability, that is, the probability of failure, is acceptable for a 10 hour mission time or risk interval.« less

Characterizing the role of the hippocampus during episodic simulation and encoding.

PubMed

Thakral, Preston P; Benoit, Roland G; Schacter, Daniel L

2017-12-01

The hippocampus has been consistently associated with episodic simulation (i.e., the mental construction of a possible future episode). In a recent study, we identified an anterior-posterior temporal dissociation within the hippocampus during simulation. Specifically, transient simulation-related activity occurred in relatively posterior portions of the hippocampus and sustained activity occurred in anterior portions. In line with previous theoretical proposals of hippocampal function during simulation, the posterior hippocampal activity was interpreted as reflecting a transient retrieval process for the episodic details necessary to construct an episode. In contrast, the sustained anterior hippocampal activity was interpreted as reflecting the continual recruitment of encoding and/or relational processing associated with a simulation. In the present study, we provide a direct test of these interpretations by conducting a subsequent memory analysis of our previously published data to assess whether successful encoding during episodic simulation is associated with the anterior hippocampus. Analyses revealed a subsequent memory effect (i.e., later remembered > later forgotten simulations) in the anterior hippocampus. The subsequent memory effect was transient and not sustained. Taken together, the current findings provide further support for a component process model of hippocampal function during simulation. That is, unique regions of the hippocampus support dissociable processes during simulation, which include the transient retrieval of episodic information, the sustained binding of such information into a coherent episode, and the transient encoding of that episode for later retrieval. © 2017 Wiley Periodicals, Inc.

Time-independent hybrid enrichment for finite element solution of transient conduction–radiation in diffusive grey media

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

Mohamed, M. Shadi, E-mail: m.s.mohamed@durham.ac.uk; Seaid, Mohammed; Trevelyan, Jon

2013-10-15

We investigate the effectiveness of the partition-of-unity finite element method for transient conduction–radiation problems in diffusive grey media. The governing equations consist of a semi-linear transient heat equation for the temperature field and a stationary diffusion approximation to the radiation in grey media. The coupled equations are integrated in time using a semi-implicit method in the finite element framework. We show that for the considered problems, a combination of hyperbolic and exponential enrichment functions based on an approximation of the boundary layer leads to improved accuracy compared to the conventional finite element method. It is illustrated that this approach canmore » be more efficient than using h adaptivity to increase the accuracy of the finite element method near the boundary walls. The performance of the proposed partition-of-unity method is analyzed on several test examples for transient conduction–radiation problems in two space dimensions.« less

Optical Angular Motion Sensor

DTIC Science & Technology

1975-04-01

wedge at 10 Hz Background Radiation Completed Input Power Partially Transients, ripple and reverse Completed polarity power tests not per- formed...cases, indicating that the ACC was functioning properly. The changes seen were attributed to wedge angles and birefringent effects in the attenuators...noise for testing and is not within the specified value. 9.5.2 Method 2 A counter-rotating wedge of 15 arc minutes total deflection was used to measure

40 CFR 1039.510 - Which duty cycles do I use for transient testing?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Which duty cycles do I use for... ENGINES Test Procedures § 1039.510 Which duty cycles do I use for transient testing? (a) Measure emissions by testing the engine on a dynamometer with one of the following transient duty cycles to determine...

Numerical simulation of electrophoresis separation processes

NASA Technical Reports Server (NTRS)

Ganjoo, D. K.; Tezduyar, T. E.

1986-01-01

A new Petrov-Galerkin finite element formulation has been proposed for transient convection-diffusion problems. Most Petrov-Galerkin formulations take into account the spatial discretization, and the weighting functions so developed give satisfactory solutions for steady state problems. Though these schemes can be used for transient problems, there is scope for improvement. The schemes proposed here, which consider temporal as well as spatial discretization, provide improved solutions. Electrophoresis, which involves the motion of charged entities under the influence of an applied electric field, is governed by equations similiar to those encountered in fluid flow problems, i.e., transient convection-diffusion equations. Test problems are solved in electrophoresis and fluid flow. The results obtained are satisfactory. It is also expected that these schemes, suitably adapted, will improve the numerical solutions of the compressible Euler and the Navier-Stokes equations.

Time-domain parameter identification of aeroelastic loads by forced-vibration method for response of flexible structures subject to transient wind

NASA Astrophysics Data System (ADS)

Cao, Bochao

Slender structures representing civil, mechanical and aerospace systems such as long-span bridges, high-rise buildings, stay cables, power-line cables, high light mast poles, crane-booms and aircraft wings could experience vortex-induced and buffeting excitations below their design wind speeds and divergent self-excited oscillations (flutter) beyond a critical wind speed because these are flexible. Traditional linear aerodynamic theories that are routinely applied for their response prediction are not valid in the galloping, or near-flutter regime, where large-amplitude vibrations could occur and during non-stationary and transient wind excitations that occur, for example, during hurricanes, thunderstorms and gust fronts. The linear aerodynamic load formulation for lift, drag and moment are expressed in terms of aerodynamic functions in frequency domain that are valid for straight-line winds which are stationary or weakly-stationary. Application of the frequency domain formulation is restricted from use in the nonlinear and transient domain because these are valid for linear models and stationary wind. The time-domain aerodynamic force formulations are suitable for finite element modeling, feedback-dependent structural control mechanism, fatigue-life prediction, and above all modeling of transient structural behavior during non-stationary wind phenomena. This has motivated the developing of time-domain models of aerodynamic loads that are in parallel to the existing frequency-dependent models. Parameters defining these time-domain models can be now extracted from wind tunnel tests, for example, the Rational Function Coefficients defining the self-excited wind loads can be extracted using section model tests using the free vibration technique. However, the free vibration method has some limitations because it is difficult to apply at high wind speeds, in turbulent wind environment, or on unstable cross sections with negative aerodynamic damping. In the current research, new algorithms were developed based on forced vibration technique for direct extraction of the Rational Functions. The first of the two algorithms developed uses the two angular phase lag values between the measured vertical or torsional displacement and the measured aerodynamic lift and moment produced on the section model subject to forced vibration to identify the Rational Functions. This algorithm uses two separate one-degree-of-freedom tests (vertical or torsional) to identify all the four Rational Functions or corresponding Rational Function Coefficients for a two degrees-of-freedom (DOF) vertical-torsional vibration model. It was applied to a streamlined section model and the results compared well with those obtained from earlier free vibration experiment. The second algorithm that was developed is based on direct least squares method. It uses all the data points of displacements and aerodynamic lift and moment instead of phase lag values for more accurate estimates. This algorithm can be used for one-, two- and three-degree-of-freedom motions. A two-degree-of-freedom forced vibration system was developed and the algorithm was shown to work well for both streamlined and bluff section models. The uniqueness of the second algorithms lies in the fact that it requires testing the model at only two wind speeds for extraction of all four Rational Functions. The Rational Function Coefficients that were extracted for a streamlined section model using the two-DOF Least Squares algorithm were validated in a separate wind tunnel by testing a larger scaled model subject to straight-line, gusty and boundary-layer wind.

Recovering Aerodynamic Side Loads on Rocket Nozzles using Quasi-Static Strain-Gage Measurements

NASA Technical Reports Server (NTRS)

Brown, Andrew; Ruf, Joseph H.; McDaniels, David M.

2009-01-01

During over-expanded operation of rocket nozzles, which is defined to be when the exit pressure is greater than internal pressure over some part of the nozzle, the nozzle will experience a transverse forcing function due to the pressure differential across the nozzle wall. Over-expansion occurs during the nozzle start-up and shutdown transient, even in high-altitude engines, because most test facilities cannot completely reproduce the near-vacuum pressures at those altitudes. During this transient, the pressure differential moves axially down the nozzle as it becomes pressurized, but this differential is never perfectly symmetric circumferentially. The character of the forcing function is highly complex and defined by a series of restricted and free shock separations. The subject of this paper is the determination of the magnitude of this loading during sub-scale testing via measurement of the structural dynamic response of the nozzle and its support structure. An initial attempt at back-calculating this load using the inverse of the transfer function was performed, but this attempt was shown to be highly susceptible to numerical error. The final method chosen was to use statically calibrated strain data and to filter out the system fundamental frequency such that the measured response yields close to the correct dynamic loading function. This method was shown to capture 93% of the pressure spectral energy using controlled load shaker testing. This method is one of the only practical ways for the inverse determination of the forcing function for non-stationary excitations, and, to the authors' knowledge, has not been described in the literature to date.

A composite viscoelastic model for incorporating grain boundary sliding and transient diffusion creep; correlating creep and attenuation responses for materials with a fine grain size

NASA Astrophysics Data System (ADS)

Sundberg, Marshall; Cooper, Reid F.

2010-07-01

A new viscoelastic creep function that incorporates both the effects of elastically-accommodated grain boundary sliding (GBS) and transient diffusion creep is proposed. It is demonstrated that this model can simultaneously describe both the transient microcreep curves and the shear attenuation/modulus dispersion in a fine-grained (d ∼ 5 µm) peridotite (olivine + 39 vol. % orthopyroxene) specimen. Low-frequency shear attenuation, ? , and modulus dispersion, G(ω), spectra were measured in a one-atmosphere reciprocating torsion apparatus at temperatures of 1200 ≤ T ≤ 1300°C and frequencies of 10-2.25 ≤ f ≤ 100 Hz. Reciprocating tests were complemented by a series of small stress (τ ∼ 90 kPa) microcreep experiments at the same temperatures. In contrast to previous models where the parameters of viscoelastic models are derived by fitting the Laplace transform of the creep function to measured attenuation spectra, the parameters are derived solely from the fit of the creep function to the experimental microcreep curves using different published expressions for the relaxation strength of elastically-accommodated GBS. This approach may allow future studies to better link the large dataset of steady-state creep response to the dynamic attenuation behavior.

Groundwater response to changing water-use practices in sloping aquifers using convolution of transient response functions

USDA-ARS?s Scientific Manuscript database

This study examines the impact of a sloping base on the movement of transients through groundwater systems. Dimensionless variables and regression of model results are employed to develop functions relating the transient change in saturated thickness to the distance upgradient and downgradient from ...

Effects of Detrital Subsidies on Soft-Sediment Ecosystem Function Are Transient and Source-Dependent.

PubMed

Gladstone-Gallagher, Rebecca V; Lohrer, Andrew M; Lundquist, Carolyn J; Pilditch, Conrad A

2016-01-01

Detrital subsidies from marine macrophytes are prevalent in temperate estuaries, and their role in structuring benthic macrofaunal communities is well documented, but the resulting impact on ecosystem function is not understood. We conducted a field experiment to test the effects of detrital decay on soft-sediment primary production, community metabolism and nutrient regeneration (measures of ecosystem function). Twenty four (2 m2) plots were established on an intertidal sandflat, to which we added 0 or 220 g DW m-2 of detritus from either mangroves (Avicennia marina), seagrass (Zostera muelleri), or kelp (Ecklonia radiata) (n = 6 plots per treatment). Then, after 4, 17 and 46 d we measured ecosystem function, macrofaunal community structure and sediment properties. We hypothesized that (1) detrital decay would stimulate benthic primary production either by supplying nutrients to the benthic macrophytes, or by altering the macrofaunal community; and (2) ecosystem responses would depend on the stage and rate of macrophyte decay (a function of source). Avicennia detritus decayed the slowest with a half-life (t50) of 46 d, while Zostera and Ecklonia had t50 values of 28 and 2.6 d, respectively. However, ecosystem responses were not related to these differences. Instead, we found transient effects (up to 17 d) of Avicennia and Ecklonia detritus on benthic primary production, where initially (4 d) these detrital sources suppressed primary production, but after 17 d, primary production was stimulated in Avicennia plots relative to controls. Other ecosystem function response variables and the macrofaunal community composition were not altered by the addition of detritus, but did vary with time. By sampling ecosystem function temporally, we were able to capture the in situ transient effects of detrital subsidies on important benthic ecosystem functions.

Transient Hypothyroidism after Radioiodine for Graves’ Disease: Challenges in Interpreting Thyroid Function Tests

PubMed Central

Sheehan, Michael T.; Doi, Suhail A.R.

2016-01-01

Graves’ disease is the most common cause of hyperthyroidism and is often managed with radioactive iodine (RAI) therapy. With current dosing schemes, the vast majority of patients develop permanent post-RAI hypothyroidism and are placed on life-long levothyroxine therapy. This hypothyroidism typically occurs within the first 3 to 6 months after RAI therapy is administered. Indeed, patients are typically told to expect life-long thyroid hormone replacement therapy to be required within this timeframe and many providers expect this post-RAI hypothyroidism to be complete and permanent. There is, however, a small subset of patients in whom a transient post-RAI hypothyroidism develops which, initially, presents exactly as the typical permanent hypothyroidism. In some cases the transient hypothyroidism leads to a period of euthyroidism of variable duration eventually progressing to permanent hypothyroidism. In others, persistent hyperthyroidism requires a second dose of RAI. Failure to appreciate and recognize the possibility of transient post-RAI hypothyroidism can delay optimal and appropriate treatment of the patient. We herein describe five cases of transient post-RAI hypothyroidism which highlight this unusual sequence of events. Increased awareness of this possible outcome after RAI for Graves’ disease will help in the timely management of patients. PMID:26864507

Assaying effector function in planta using double-barreled particle bombardment.

PubMed

Kale, Shiv D; Tyler, Brett M

2011-01-01

The biolistic transient gene expression assay is a beneficial tool for studying gene function in vivo. However, biolistic transient assay systems have inherent pitfalls that often cause experimental inaccuracies such as poor transformation efficiency, which can be confused with biological phenomena. The double-barreled gene gun device is an inexpensive and highly effective attachment that enables statistically significant data to be obtained with one-tenth the number of experimental replicates compared to conventional biolistic assays. The principle behind the attachment is to perform two simultaneous bombardments with control and test DNA preparations onto the same leaf. The control bombardment measures the efficiency of the transformation while the ratio of the test bombardment to the control bombardment measures the activity of the gene of interest. With care, the ratio between the pair of bombardments can be highly reproducible from bombardment to bombardment. The double-barreled attachment has been used to study plant resistance (R) gene-mediated responses to effectors, induction and suppression of cell death by a wide variety of pathogen and host molecules, and the role of oömycete effector RXLR motifs in cell reentry.

Advanced Instrumentation for Transient Reactor Testing

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

Corradini, Michael L.; Anderson, Mark; Imel, George

Transient testing involves placing fuel or material into the core of specialized materials test reactors that are capable of simulating a range of design basis accidents, including reactivity insertion accidents, that require the reactor produce short bursts of intense highpower neutron flux and gamma radiation. Testing fuel behavior in a prototypic neutron environment under high-power, accident-simulation conditions is a key step in licensing nuclear fuels for use in existing and future nuclear power plants. Transient testing of nuclear fuels is needed to develop and prove the safety basis for advanced reactors and fuels. In addition, modern fuel development and designmore » increasingly relies on modeling and simulation efforts that must be informed and validated using specially designed material performance separate effects studies. These studies will require experimental facilities that are able to support variable scale, highly instrumented tests providing data that have appropriate spatial and temporal resolution. Finally, there are efforts now underway to develop advanced light water reactor (LWR) fuels with enhanced performance and accident tolerance. These advanced reactor designs will also require new fuel types. These new fuels need to be tested in a controlled environment in order to learn how they respond to accident conditions. For these applications, transient reactor testing is needed to help design fuels with improved performance. In order to maximize the value of transient testing, there is a need for in-situ transient realtime imaging technology (e.g., the neutron detection and imaging system like the hodoscope) to see fuel motion during rapid transient excursions with a higher degree of spatial and temporal resolution and accuracy. There also exists a need for new small, compact local sensors and instrumentation that are capable of collecting data during transients (e.g., local displacements, temperatures, thermal conductivity, neutron flux, etc.).« less

Real-time acquisition and preprocessing system of transient electromagnetic data based on LabVIEW

NASA Astrophysics Data System (ADS)

Zhao, Huinan; Zhang, Shuang; Gu, Lingjia; Sun, Jian

2014-09-01

Transient electromagnetic method (TEM) is regarded as an everlasting issue for geological exploration. It is widely used in many research fields, such as mineral exploration, hydrogeology survey, engineering exploration and unexploded ordnance detection. The traditional measurement systems are often based on ARM DSP or FPGA, which have not real-time display, data preprocessing and data playback functions. In order to overcome the defects, a real-time data acquisition and preprocessing system based on LabVIEW virtual instrument development platform is proposed in the paper, moreover, a calibration model is established for TEM system based on a conductivity loop. The test results demonstrated that the system can complete real-time data acquisition and system calibration. For Transmit-Loop-Receive (TLR) response, the correlation coefficient between the measured results and the calculated results is 0.987. The measured results are basically consistent with the calculated results. Through the late inversion process for TLR, the signal of underground conductor was obtained. In the complex test environment, abnormal values usually exist in the measured data. In order to solve this problem, the judgment and revision algorithm of abnormal values is proposed in the paper. The test results proved that the proposed algorithm can effectively eliminate serious disturbance signals from the measured transient electromagnetic data.

Rapamycin/IL-2 combination therapy in patients with type 1 diabetes augments Tregs yet transiently impairs β-cell function.

PubMed

Long, S Alice; Rieck, Mary; Sanda, Srinath; Bollyky, Jennifer B; Samuels, Peter L; Goland, Robin; Ahmann, Andrew; Rabinovitch, Alex; Aggarwal, Sudeepta; Phippard, Deborah; Turka, Laurence A; Ehlers, Mario R; Bianchine, Peter J; Boyle, Karen D; Adah, Steven A; Bluestone, Jeffrey A; Buckner, Jane H; Greenbaum, Carla J

2012-09-01

Rapamycin/interleukin-2 (IL-2) combination treatment of NOD mice effectively treats autoimmune diabetes. We performed a phase 1 clinical trial to test the safety and immunologic effects of rapamycin/IL-2 combination therapy in type 1 diabetic (T1D) patients. Nine T1D subjects were treated with 2-4 mg/day rapamycin orally for 3 months and 4.5 × 10(6) IU IL-2 s.c. three times per week for 1 month. β-Cell function was monitored by measuring C-peptide. Immunologic changes were monitored using flow cytometry and serum analyses. Regulatory T cells (Tregs) increased within the first month of therapy, yet clinical and metabolic data demonstrated a transient worsening in all subjects. The increase in Tregs was transient, paralleling IL-2 treatment, whereas the response of Tregs to IL-2, as measured by STAT5 phosphorylation, increased and persisted after treatment. No differences were observed in effector T-cell subset frequencies, but an increase in natural killer cells and eosinophils occurred with IL-2 therapy. Rapamycin/IL-2 therapy, as given in this phase 1 study, resulted in transient β-cell dysfunction despite an increase in Tregs. Such results highlight the difficulties in translating therapies to the clinic and emphasize the importance of broadly interrogating the immune system to evaluate the effects of therapy.

Effects of transient versus chronic loneliness on cognitive function in older adults: Findings from the Chinese Longitudinal Healthy Longevity Survey

PubMed Central

Zhong, Bao-Liang; Chen, Shu-Lin; Conwell, Yeates

2016-01-01

Objectives Loneliness is a risk factor for poor cognitive function in older adults (OAs), however, to date, no studies have explored whether transient and chronic loneliness have differential effects on OAs’ cognitive function. The present study evaluates the impacts of transient versus chronic loneliness on cognitive function in OAs. Design A 6-year follow-up cohort study. Setting Rural and urban communities of 23 provinces in China. Participants 2995 OAs who were cognitively healthy (the modified Mini-mental State Examination [mMMSE] ≥ 14) and completed the 2005, 2008 and 2011 waves of the Chinese Longitudinal Healthy Longevity Survey. Measurements Self-report loneliness and mMMSE. Results Both transient (β=−0.389, t=−2.191, df=2994, P=0.029) and chronic loneliness (β=−0.640, t=−2.109, df=2994, P=0.035) were significantly associated with lower mMMSE scores six years later, net of potential confounding effects of baseline covariates. Sensitivity analyses found that regression coefficients of mMMSE scores on transient loneliness were statistically significant and relatively stable across samples with various levels of cognitive function. In contrast, coefficients of mMMSE scores on chronic loneliness were statistically significant only among samples with normal cognitive function and the absolute values of these coefficients increased with the degree of cognitive health of the analytic sample. In the sample with mMMSE≥21, the coefficient of chronic loneliness was 2.59 times as large as that of transient loneliness (−1.017 versus −0.392). Conclusions Both transient and chronic loneliness are significant predictors of cognitive decline in OAs. Relative to transient loneliness, chronic loneliness has more pronounced negative effects on the brain health of OAs. PMID:26905049

Identification of modal parameters including unmeasured forces and transient effects

NASA Astrophysics Data System (ADS)

Cauberghe, B.; Guillaume, P.; Verboven, P.; Parloo, E.

2003-08-01

In this paper, a frequency-domain method to estimate modal parameters from short data records with known input (measured) forces and unknown input forces is presented. The method can be used for an experimental modal analysis, an operational modal analysis (output-only data) and the combination of both. A traditional experimental and operational modal analysis in the frequency domain starts respectively, from frequency response functions and spectral density functions. To estimate these functions accurately sufficient data have to be available. The technique developed in this paper estimates the modal parameters directly from the Fourier spectra of the outputs and the known input. Instead of using Hanning windows on these short data records the transient effects are estimated simultaneously with the modal parameters. The method is illustrated, tested and validated by Monte Carlo simulations and experiments. The presented method to process short data sequences leads to unbiased estimates with a small variance in comparison to the more traditional approaches.

40 CFR Appendix E to Subpart S of... - Transient Test Driving Cycle

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 2 2010-07-01 2010-07-01 false Transient Test Driving Cycle E Appendix... Driving Cycle (I) Driver's trace. All excursions in the transient driving cycle shall be evaluated by the... shall cause a test to be void. In addition, provisions shall be available to utilize cycle validation...

40 CFR 1048.510 - What transient duty cycles apply for laboratory testing?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false What transient duty cycles apply for... Procedures § 1048.510 What transient duty cycles apply for laboratory testing? (a) Starting with the 2007 model year, measure emissions by testing the engine on a dynamometer with the duty cycle described in...

Risk Factors and Cognitive Relevance of Cortical Cerebral Microinfarcts in Patients With Ischemic Stroke or Transient Ischemic Attack.

PubMed

Wang, Zhaolu; van Veluw, Susanne J; Wong, Adrian; Liu, Wenyan; Shi, Lin; Yang, Jie; Xiong, Yunyun; Lau, Alexander; Biessels, Geert Jan; Mok, Vincent C T

2016-10-01

It was recently demonstrated that cerebral microinfarcts (CMIs) can be detected in vivo using 3.0 tesla (T) magnetic resonance imaging. We investigated the prevalence, risk factors, and the longitudinal cognitive consequence of cortical CMIs on 3.0T magnetic resonance imaging, in patients with ischemic stroke or transient ischemic attack. A total of 231 patients undergoing 3.0T magnetic resonance imaging were included. Montreal Cognitive Assessment was used to evaluate global cognitive functions and cognitive domains (memory, language, and attention visuospatial and executive functions). Cognitive changes were represented by the difference in Montreal Cognitive Assessment score between baseline and 28-month after stroke/transient ischemic attack. The cross-sectional and longitudinal associations between cortical CMIs and cognitive functions were explored using ANCOVA and regression models. Cortical CMIs were observed in 34 patients (14.7%), including 13 patients with acute (hyperintense on diffusion-weighted imaging) and 21 with chronic CMIs (isointense on diffusion-weighted imaging). Atrial fibrillation was a risk factor for all cortical CMIs (odds ratio, 4.8; 95% confidence interval, 1.5-14.9; P=0.007). Confluent white matter hyperintensities was associated with chronic CMIs (odds ratio, 2.8; 95% confidence interval, 1.0-7.8; P=0.047). The presence of cortical CMIs at baseline was associated with worse visuospatial functions at baseline and decline over 28-month follow-up (β=0.5; 95% confidence interval, 0.1-1.0; P=0.008, adjusting for brain atrophy, white matter hyperintensities, lacunes, and microbleeds). Cortical CMIs are a common finding in patients with stroke/transient ischemic attack. Associations between CMI with atrial fibrillation and white matter hyperintensities suggest that these lesions have a heterogeneous cause, involving microembolism and cerebral small vessel disease. CMI seemed to preferentially impact visuospatial functions as assessed by a cognitive screening test. © 2016 American Heart Association, Inc.

Heavy Ion Transient Characterization of a Photobit Hardened-by-Design Active Pixel Sensor Array

NASA Technical Reports Server (NTRS)

Marshall, Paul W.; Byers, Wheaton B.; Conger, Christopher; Eid, El-Sayed; Gee, George; Jones, Michael R.; Marshall, Cheryl J.; Reed, Robert; Pickel, Jim; Kniffin, Scott

2002-01-01

This paper presents heavy ion data on the single event transient (SET) response of a Photobit active pixel sensor (APS) four quadrant test chip with different radiation tolerant designs in a standard 0.35 micron CMOS process. The physical design techniques of enclosed geometry and P-channel guard rings are used to design the four N-type active photodiode pixels as described in a previous paper. Argon transient measurements on the 256 x 256 chip array as a function of incident angle show a significant variation in the amount of charge collected as well as the charge spreading dependent on the pixel type. The results are correlated with processing and design information provided by Photobit. In addition, there is a large degree of statistical variability between individual ion strikes. No latch-up is observed up to an LET of 106 MeV/mg/sq cm.

Data and results of a laboratory investigation of microprocessor upset caused by simulated lightning-induced analog transients

NASA Technical Reports Server (NTRS)

Belcastro, C. M.

1984-01-01

Advanced composite aircraft designs include fault-tolerant computer-based digital control systems with thigh reliability requirements for adverse as well as optimum operating environments. Since aircraft penetrate intense electromagnetic fields during thunderstorms, onboard computer systems maya be subjected to field-induced transient voltages and currents resulting in functional error modes which are collectively referred to as digital system upset. A methodology was developed for assessing the upset susceptibility of a computer system onboard an aircraft flying through a lightning environment. Upset error modes in a general-purpose microprocessor were studied via tests which involved the random input of analog transients which model lightning-induced signals onto interface lines of an 8080-based microcomputer from which upset error data were recorded. The application of Markov modeling to upset susceptibility estimation is discussed and a stochastic model development.

Predicting the Reliability of Brittle Material Structures Subjected to Transient Proof Test and Service Loading

NASA Astrophysics Data System (ADS)

Nemeth, Noel N.; Jadaan, Osama M.; Palfi, Tamas; Baker, Eric H.

Brittle materials today are being used, or considered, for a wide variety of high tech applications that operate in harsh environments, including static and rotating turbine parts, thermal protection systems, dental prosthetics, fuel cells, oxygen transport membranes, radomes, and MEMS. Designing brittle material components to sustain repeated load without fracturing while using the minimum amount of material requires the use of a probabilistic design methodology. The NASA CARES/Life 1 (Ceramic Analysis and Reliability Evaluation of Structure/Life) code provides a general-purpose analysis tool that predicts the probability of failure of a ceramic component as a function of its time in service. This capability includes predicting the time-dependent failure probability of ceramic components against catastrophic rupture when subjected to transient thermomechanical loads (including cyclic loads). The developed methodology allows for changes in material response that can occur with temperature or time (i.e. changing fatigue and Weibull parameters with temperature or time). For this article an overview of the transient reliability methodology and how this methodology is extended to account for proof testing is described. The CARES/Life code has been modified to have the ability to interface with commercially available finite element analysis (FEA) codes executed for transient load histories. Examples are provided to demonstrate the features of the methodology as implemented in the CARES/Life program.

EBR-II high-ramp transients under computer control

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

Forrester, R.J.; Larson, H.A.; Christensen, L.J.

1983-01-01

During reactor run 122, EBR-II was subjected to 13 computer-controlled overpower transients at ramps of 4 MWt/s to qualify the facility and fuel for transient testing of LMFBR oxide fuels as part of the EBR-II operational-reliability-testing (ORT) program. A computer-controlled automatic control-rod drive system (ACRDS), designed by EBR-II personnel, permitted automatic control on demand power during the transients.

Lifetime Reliability Prediction of Ceramic Structures Under Transient Thermomechanical Loads

NASA Technical Reports Server (NTRS)

Nemeth, Noel N.; Jadaan, Osama J.; Gyekenyesi, John P.

2005-01-01

An analytical methodology is developed to predict the probability of survival (reliability) of ceramic components subjected to harsh thermomechanical loads that can vary with time (transient reliability analysis). This capability enables more accurate prediction of ceramic component integrity against fracture in situations such as turbine startup and shutdown, operational vibrations, atmospheric reentry, or other rapid heating or cooling situations (thermal shock). The transient reliability analysis methodology developed herein incorporates the following features: fast-fracture transient analysis (reliability analysis without slow crack growth, SCG); transient analysis with SCG (reliability analysis with time-dependent damage due to SCG); a computationally efficient algorithm to compute the reliability for components subjected to repeated transient loading (block loading); cyclic fatigue modeling using a combined SCG and Walker fatigue law; proof testing for transient loads; and Weibull and fatigue parameters that are allowed to vary with temperature or time. Component-to-component variation in strength (stochastic strength response) is accounted for with the Weibull distribution, and either the principle of independent action or the Batdorf theory is used to predict the effect of multiaxial stresses on reliability. The reliability analysis can be performed either as a function of the component surface (for surface-distributed flaws) or component volume (for volume-distributed flaws). The transient reliability analysis capability has been added to the NASA CARES/ Life (Ceramic Analysis and Reliability Evaluation of Structures/Life) code. CARES/Life was also updated to interface with commercially available finite element analysis software, such as ANSYS, when used to model the effects of transient load histories. Examples are provided to demonstrate the features of the methodology as implemented in the CARES/Life program.

Small-spot laser-exposure effects on visual function

NASA Astrophysics Data System (ADS)

Zwick, Harry; Robbins, David O.; Stuck, Bruce E.; Lund, David J.; Reynolds, Scottie B.; Nawim, Maqsood; Schuschereba, Steven T.

1990-07-01

Laser field exposure effects on visual function involve produc tJon of minimal spot irradiation on or near the huntan fovea. Functional effects of such exposure may involve transient or perinanent change in visual function depending upon exposure dose. While Maximun Permissible Exposure (MPE) lirrtits define exposure in terins of threshold retinal niorphological change such limits are not applicable with regard to transient changes in visual function below MPE limits induced by alteration in retinal physiological processes. Mechanisms of transient and permanent functional change reported in these exper iments point out the need to examine laser safety limits in terms of both the functional as well as the morphological disturbance induced in retinal tissue. L

Diffuse dispersive delay and the time convolution/attenuation of transients

NASA Technical Reports Server (NTRS)

Bittner, Burt J.

1991-01-01

Test data and analytic evaluations are presented to show that relatively poor 100 KHz shielding of 12 Db can effectively provide an electromagnetic pulse transient reduction of 100 Db. More importantly, several techniques are shown for lightning surge attenuation as an alternative to crowbar, spark gap, or power zener type clipping which simply reflects the surge. A time delay test method is shown which allows CW testing, along with a convolution program to define transient shielding effectivity where the Fourier phase characteristics of the transient are known or can be broadly estimated.

The use of transient evoked otoacoustic emissions as a hearing screen following grommet insertion.

PubMed

Dale, O T; McCann, L J; Thio, D; Wells, S C; Drysdale, A J

2011-07-01

This study aimed to evaluate the sensitivity of transient evoked otoacoustic emission testing as a screening tool for hearing loss in children, after grommet insertion. A prospective study was conducted of 48 children (91 ears) aged three to 16 years who had undergone grommet insertion for glue ear. At post-operative review, pure tone audiometry was performed followed by transient evoked otoacoustic emission testing. Outcomes for both tests, in each ear, were compared. The pure tone audiometry threshold was ≤ 20 dB in 85 ears (93.4 per cent), 25 dB in two ears (2.2 per cent) and ≥ 30 dB in four ears (4.4 per cent). Transient evoked otoacoustic emissions were detected in 69 ears (75.8 per cent). The sensitivity of transient evoked otoacoustic emission testing for detecting hearing loss was 100 per cent for ≥ 30 dB loss but only 66.7 per cent for ≥ 25 dB loss. Transient evoked otoacoustic emission testing offers a sensitive means of detecting hearing loss of ≥ 30 dB following grommet insertion in children. However, the use of such testing as a screening tool may miss some cases of mild hearing loss.

Unconventional repertoire profile is imprinted during acute chikungunya infection for natural killer cells polarization toward cytotoxicity.

PubMed

Petitdemange, Caroline; Becquart, Pierre; Wauquier, Nadia; Béziat, Vivien; Debré, Patrice; Leroy, Eric M; Vieillard, Vincent

2011-09-01

Chikungunya virus (CHIKV) is a worldwide emerging pathogen. In humans it causes a syndrome characterized by high fever, polyarthritis, and in some cases lethal encephalitis. Growing evidence indicates that the innate immune response plays a role in controlling CHIKV infection. We show here that CHIKV induces major but transient modifications in NK-cell phenotype and function soon after the onset of acute infection. We report a transient clonal expansion of NK cells that coexpress CD94/NKG2C and inhibitory receptors for HLA-C1 alleles and are correlated with the viral load. Functional tests reveal cytolytic capacity driven by NK cells in the absence of exogenous signals and severely impaired IFN-γ production. Collectively these data provide insight into the role of this unique subset of NK cells in controlling CHIKV infection by subset-specific expansion in response to acute infection, followed by a contraction phase after viral clearance.

Characterizing RNA ensembles from NMR data with kinematic models

PubMed Central

Fonseca, Rasmus; Pachov, Dimitar V.; Bernauer, Julie; van den Bedem, Henry

2014-01-01

Functional mechanisms of biomolecules often manifest themselves precisely in transient conformational substates. Researchers have long sought to structurally characterize dynamic processes in non-coding RNA, combining experimental data with computer algorithms. However, adequate exploration of conformational space for these highly dynamic molecules, starting from static crystal structures, remains challenging. Here, we report a new conformational sampling procedure, KGSrna, which can efficiently probe the native ensemble of RNA molecules in solution. We found that KGSrna ensembles accurately represent the conformational landscapes of 3D RNA encoded by NMR proton chemical shifts. KGSrna resolves motionally averaged NMR data into structural contributions; when coupled with residual dipolar coupling data, a KGSrna ensemble revealed a previously uncharacterized transient excited state of the HIV-1 trans-activation response element stem–loop. Ensemble-based interpretations of averaged data can aid in formulating and testing dynamic, motion-based hypotheses of functional mechanisms in RNAs with broad implications for RNA engineering and therapeutic intervention. PMID:25114056

Outcomes of transient evoked otoacoustic emission testing in 6-year-old school children: a comparison with pure tone screening and tympanometry.

PubMed

Driscoll, C; Kei, J; McPherson, B

2001-01-01

(1) To establish test performance measures for Transient Evoked Otoacoustic Emission testing of 6-year-old children in a school setting; (2) To investigate whether Transient Evoked Otoacoustic Emission testing provides a more accurate and effective alternative to a pure tone screening plus tympanometry protocol. Pure tone screening, tympanometry and transient evoked otoacoustic emission data were collected from 940 subjects (1880 ears), with a mean age of 6.2 years. Subjects were tested in non-sound-treated rooms within 22 schools. Receiver operating characteristics curves along with specificity, sensitivity, accuracy and efficiency values were determined for a variety of transient evoked otoacoustic emission/pure tone screening/tympanometry comparisons. The Transient Evoked Otoacoustic Emission failure rate for the group was 20.3%. The failure rate for pure tone screening was found to be 8.9%, whilst 18.6% of subjects failed a protocol consisting of combined pure tone screening and tympanometry results. In essence, findings from the comparison of overall Transient Evoked Otoacoustic Emission pass/fail with overall pure tone screening pass/fail suggested that use of a modified Rhode Island Hearing Assessment Project criterion would result in a very high probability that a child with a pass result has normal hearing (true negative). However, the hit rate was only moderate. Selection of a signal-to-noise ratio (SNR) criterion set at > or =1 dB appeared to provide the best test performance measures for the range of SNR values investigated. Test performance measures generally declined when tympanometry results were included, with the exception of lower false alarm rates and higher positive predictive values. The exclusion of low frequency data from the Transient Evoked Otoacoustic Emission SNR versus pure tone screening analysis resulted in improved performance measures. The present study poses several implications for the clinical implementation of Transient Evoked Otoacoustic Emission screening for entry level school children. Transient Evoked Otoacoustic Emission pass/fail criteria will require revision. The findings of the current investigation offer support to the possible replacement of pure tone screening with Transient Evoked Otoacoustic Emission testing for 6-year-old children. However, they do not suggest the replacement of the pure tone screening plus tympanometry battery.

Reduced Performance During a Sentence Repetition Task by Continuous Theta-Burst Magnetic Stimulation of the Pre-supplementary Motor Area.

PubMed

Dietrich, Susanne; Hertrich, Ingo; Müller-Dahlhaus, Florian; Ackermann, Hermann; Belardinelli, Paolo; Desideri, Debora; Seibold, Verena C; Ziemann, Ulf

2018-01-01

The pre-supplementary motor area (pre-SMA) is engaged in speech comprehension under difficult circumstances such as poor acoustic signal quality or time-critical conditions. Previous studies found that left pre-SMA is activated when subjects listen to accelerated speech. Here, the functional role of pre-SMA was tested for accelerated speech comprehension by inducing a transient "virtual lesion" using continuous theta-burst stimulation (cTBS). Participants were tested (1) prior to (pre-baseline), (2) 10 min after (test condition for the cTBS effect), and (3) 60 min after stimulation (post-baseline) using a sentence repetition task (formant-synthesized at rates of 8, 10, 12, 14, and 16 syllables/s). Speech comprehension was quantified by the percentage of correctly reproduced speech material. For high speech rates, subjects showed decreased performance after cTBS of pre-SMA. Regarding the error pattern, the number of incorrect words without any semantic or phonological similarity to the target context increased, while related words decreased. Thus, the transient impairment of pre-SMA seems to affect its inhibitory function that normally eliminates erroneous speech material prior to speaking or, in case of perception, prior to encoding into a semantically/pragmatically meaningful message.

Reduced Performance During a Sentence Repetition Task by Continuous Theta-Burst Magnetic Stimulation of the Pre-supplementary Motor Area

PubMed Central

Dietrich, Susanne; Hertrich, Ingo; Müller-Dahlhaus, Florian; Ackermann, Hermann; Belardinelli, Paolo; Desideri, Debora; Seibold, Verena C.; Ziemann, Ulf

2018-01-01

The pre-supplementary motor area (pre-SMA) is engaged in speech comprehension under difficult circumstances such as poor acoustic signal quality or time-critical conditions. Previous studies found that left pre-SMA is activated when subjects listen to accelerated speech. Here, the functional role of pre-SMA was tested for accelerated speech comprehension by inducing a transient “virtual lesion” using continuous theta-burst stimulation (cTBS). Participants were tested (1) prior to (pre-baseline), (2) 10 min after (test condition for the cTBS effect), and (3) 60 min after stimulation (post-baseline) using a sentence repetition task (formant-synthesized at rates of 8, 10, 12, 14, and 16 syllables/s). Speech comprehension was quantified by the percentage of correctly reproduced speech material. For high speech rates, subjects showed decreased performance after cTBS of pre-SMA. Regarding the error pattern, the number of incorrect words without any semantic or phonological similarity to the target context increased, while related words decreased. Thus, the transient impairment of pre-SMA seems to affect its inhibitory function that normally eliminates erroneous speech material prior to speaking or, in case of perception, prior to encoding into a semantically/pragmatically meaningful message. PMID:29896086

Flight experience with a fail-operational digital fly-by-wire control system

NASA Technical Reports Server (NTRS)

Brown, S. R.; Szalai, K. J.

1977-01-01

The NASA Dryden Flight Research Center is flight testing a triply redundant digital fly-by-wire (DFBW) control system installed in an F-8 aircraft. The full-time, full-authority system performs three-axis flight control computations, including stability and command augmentation, autopilot functions, failure detection and isolation, and self-test functions. Advanced control law experiments include an active flap mode for ride smoothing and maneuver drag reduction. This paper discusses research being conducted on computer synchronization, fault detection, fault isolation, and recovery from transient faults. The F-8 DFBW system has demonstrated immunity from nuisance fault declarations while quickly identifying truly faulty components.

Testing of neuroendocrine function in astronauts as related to fluid shifts

NASA Astrophysics Data System (ADS)

Sauseng-Fellegger, G.; König, E. M.; Hinghofer-Szalkay, H.; Jezová, D.; Vigas, M.

We addressed the question of optimal conditions for neuroendocrine and cardiovascular testing in astronauts. We tested stress reactions during LBNP of ≤-50 mm Hg. There was a mild transient elevation of plasma GH concentration and a nonsignificant rise of plasma ACTH, while PRL, insulin and glucose remained unchanged. Aldosterone was decreased 5 and 10 min after beginning of LBNP, thereafter rose significantly, and displayed a further significant concentration increase 5 min post-LBNP. The endocrine and cardiovascular responses to submaximal exercise were tested at 8.00 am and 8.00 pm. Exercise-induced changes of heart rate and blood pressure remained unchanged with daytime whereas plasma concentrations of epinephrine, GH and PRL in response to work load were significantly higher in the evening than in the morning. As expected, basal resting values of plasma cortisol were significantly lower in the evening than in the morning but were similar one hour after cessation of exercise. Our findings demonstrate the importance of frequent sampling in case of transient physiological phenomena, and contribute to existing knowledge on circadian influences upon neuroendocrine stress responses.

Control Performance of General Electric Fuel and Torque Regulator Operating on T31-3 Turbine-Propeller Engine in Sea-Level Test Stand

NASA Technical Reports Server (NTRS)

Oppenheimer, Frank L.; Lazar, James

1951-01-01

A .General Electric fuel and torque regulator was tested in conjunction with a T31-3 turbine-propeller engine in the sea-level static test stand at the NACA Lewis laboratory. The engine and control were operated over the entire speed range: 11,000 rpm, nominal flight idle, to 13,000 rpm, full power. Steady-state and transient data were recorded and are presented with a description of the four control loops being used in the system. Results of this investigation indicated that single-lever control operation was satisfactory under conditions of test. Transient data presented showed that turbine-outlet temperature did overshoot maximum operating value on acceleration but that the time duration of overshoot did not exceed approximately 1 second. This temperature limiting resulted from a control on fuel flow as a function of engine speed. Speed and torque first reached their desired values 0.4 second from the time of change in power-setting lever position. Maximum speed overshoot was 3 percent.

Gamma-ray burster recurrence timescales

NASA Technical Reports Server (NTRS)

Schaefer, B. E.; Cline, T. L.

1984-01-01

Three optical transients have been found which are associated with gamma-ray bursters (GRBs). The deduced recurrence timescale for these optical transients (tau sub opt) will depend on the minimum brightness for which a flash would be detected. A detailed analysis using all available data of tau sub opt as a function of E(gamma)/E(opt) is given. For flashes similar to those found in the Harvard archives, the best estimate of tau sub opt is 0.74 years, with a 99% confidence interval from 0.23 years to 4.7 years. It is currently unclear whether the optical transients from GRBs also give rise to gamma-ray events. One way to test this association is to measure the recurrence timescale of gamma-ray events tau sub gamma. A total of 210 gamma-ray error boxes were examined and it was found that the number of observed overlaps is not significantly different from the number expected from chance coincidence. This observation can be used to place limits on tau sub gamma for an assumed luminosity function. It was found that tau sub gamma is approx. 10 yr if bursts are monoenergetic. However, if GRBs have a power law luminosity function with a wide dynamic range, then the limit is tau sub gamma 0.5 yr. Hence, the gamma-ray data do not require tau sub gamma and tau sub opt to be different.

Effects of transient neonatal hyperthyrotropinemia on intellectual quotient and psychomotor performance.

PubMed

Azizi, F; Afkhami, M; Sarshar, A; Nafarabadi, M

2001-01-01

Transient neonatal hyperthyrotropinemia (TNH) occurs frequently in areas of iodine deficiency. To evaluate the effect of TNH in intellectual function and psychomotor performance, a historical cohohrt study was performed in 9 years old children with documented TNH at birth. 18 children with TNH who had been born in Mahdieh Hospital were studied at age 9 and compared to 19 matcheal children born at the same time, but having normal thyroid function at birth. Global intelligence (IQ) and psychomotor performance were evaluated with Raven and Bender-Gestalt tests, respectively. Total serum T4 and T3 by commercial RIA and TSH by IRMA. Urine was tested for iodine content by digestion method. Height and weight were similar in two groups at birth and at 9 years of age. Thyroid function tests were similar in the two groups except for TSH at birth which was higher in TNH than in control group (23.4 +/- 8.3 vs 3.6 +/- 1.0 mU/L, P < 0.001). Results of T4, T3, resine uptake, and urinary iodine at 9 years of age were not different between two groups. Mean IQ was 98 +/- 11 and 106 +/- 8 in TNH and normal children, respectively (P < 0.01). There was no significant difference between psychomotor performance in the two groups. There was no correlation between TSH at birth and IQ at 9 years of age. The present finding suggests that TNH can adversely affect longterm intellectual development.

Characterization of the space shuttle reaction control system engine

NASA Technical Reports Server (NTRS)

Wilson, M. S.; Stechman, R. C.; Edelman, R. B.; Fortune, O. F.; Economos, C.

1972-01-01

A computer program was developed and written in FORTRAN 5 which predicts the transient and steady state performance and heat transfer characteristics of a pulsing GO2/GH2 rocket engine. This program predicts the dynamic flow and ignition characteristics which, when combined in a quasi-steady state manner with the combustion and mixing analysis program, will provide the thrust and specific impulse of the engine as a function of time. The program also predicts the transient and steady state heat transfer characteristics of the engine using various cooling concepts. The computer program, test case, and documentation are presented. The program is applicable to any system capable of utilizing the FORTRAN 4 or FORTRAN 5 language.

Stability Test for Transient-Temperature Calculations

NASA Technical Reports Server (NTRS)

Campbell, W.

1984-01-01

Graphical test helps assure numerical stability of calculations of transient temperature or diffusion in composite medium. Rectangular grid forms basis of two-dimensional finite-difference model for heat conduction or other diffusion like phenomena. Model enables calculation of transient heat transfer among up to four different materials that meet at grid point.

Transient Hypothyroidism after Radioiodine for Graves' Disease: Challenges in Interpreting Thyroid Function Tests.

PubMed

Sheehan, Michael T; Doi, Suhail A R

2016-03-01

Graves' disease is the most common cause of hyperthyroidism and is often managed with radioactive iodine (RAI) therapy. With current dosing schemes, the vast majority of patients develop permanent post-RAI hypothyroidism and are placed on life-long levothyroxine therapy. This hypothyroidism typically occurs within the first 3 to 6 months after RAI therapy is administered. Indeed, patients are typically told to expect life-long thyroid hormone replacement therapy to be required within this timeframe and many providers expect this post-RAI hypothyroidism to be complete and permanent. There is, however, a small subset of patients in whom a transient post-RAI hypothyroidism develops which, initially, presents exactly as the typical permanent hypothyroidism. In some cases the transient hypothyroidism leads to a period of euthyroidism of variable duration eventually progressing to permanent hypothyroidism. In others, persistent hyperthyroidism requires a second dose of RAI. Failure to appreciate and recognize the possibility of transient post-RAI hypothyroidism can delay optimal and appropriate treatment of the patient. We herein describe five cases of transient post-RAI hypothyroidism which highlight this unusual sequence of events. Increased awareness of this possible outcome after RAI for Graves' disease will help in the timely management of patients. © 2016 Marshfield Clinic.

Transient difference solutions of the inhomogeneous wave equation - Simulation of the Green's function

NASA Technical Reports Server (NTRS)

Baumeister, K. J.

1983-01-01

A time-dependent finite difference formulation to the inhomogeneous wave equation is derived for plane wave propagation with harmonic noise sources. The difference equation and boundary conditions are developed along with the techniques to simulate the Dirac delta function associated with a concentrated noise source. Example calculations are presented for the Green's function and distributed noise sources. For the example considered, the desired Fourier transformed acoustic pressures are determined from the transient pressures by use of a ramping function and an integration technique, both of which eliminates the nonharmonic pressure associated with the initial transient.

Transient difference solutions of the inhomogeneous wave equation: Simulation of the Green's function

NASA Technical Reports Server (NTRS)

Baumeiste, K. J.

1983-01-01

A time-dependent finite difference formulation to the inhomogeneous wave equation is derived for plane wave propagation with harmonic noise sources. The difference equation and boundary conditions are developed along with the techniques to simulate the Dirac delta function associated with a concentrated noise source. Example calculations are presented for the Green's function and distributed noise sources. For the example considered, the desired Fourier transformed acoustic pressures are determined from the transient pressures by use of a ramping function and an integration technique, both of which eliminates the nonharmonic pressure associated with the initial transient.

Heat Pipe Reactor Dynamic Response Tests: SAFE-100 Reactor Core Prototype

NASA Technical Reports Server (NTRS)

Bragg-Sitton, Shannon M.

2005-01-01

The SAFE-I00a test article at the NASA Marshall Space Flight Center was used to simulate a variety of potential reactor transients; the SAFEl00a is a resistively heated, stainless-steel heat-pipe (HP)-reactor core segment, coupled to a gas-flow heat exchanger (HX). For these transients the core power was controlled by a point kinetics model with reactivity feedback based on core average temperature; the neutron generation time and the temperature feedback coefficient are provided as model inputs. This type of non-nuclear test is expected to provide reasonable approximation of reactor transient behavior because reactivity feedback is very simple in a compact fast reactor (simple, negative, and relatively monotonic temperature feedback, caused mostly by thermal expansion) and calculations show there are no significant reactivity effects associated with fluid in the HP (the worth of the entire inventory of Na in the core is .

Characterizing SI Engine Transient Fuel Consumption in ALPHA

EPA Science Inventory

Examine typical transient engine operation encountered over the EPA's vehicle and engine testing drive cycles to characterize that transient fuel usage, and then describe the changes made to ALPHA to better model transient engine operation.

Effects of Transient Versus Chronic Loneliness on Cognitive Function in Older Adults: Findings From the Chinese Longitudinal Healthy Longevity Survey.

PubMed

Zhong, Bao-Liang; Chen, Shu-Lin; Conwell, Yeates

2016-05-01

Loneliness is a risk factor for poor cognitive function in older adults (OAs); to date, however, no studies have explored whether transient and chronic loneliness have differential effects on OAs' cognitive function. The present study evaluates the impacts of transient versus chronic loneliness on cognitive function in OAs. A 6-year follow-up cohort study. Rural and urban communities of 22 provinces in China. 2,995 OAs who were cognitively healthy (the modified Mini-Mental State Examination [mMMSE] ≥ 14) and completed the 2005, 2008, and 2011 waves of the Chinese Longitudinal Healthy Longevity Survey. Self-report loneliness and mMMSE. Both transient (β = -0.389, t = -2.191, df = 2994, p = 0.029) and chronic loneliness (β = -0.640, t = -2.109, df = 2994, p = 0.035) were significantly associated with lower mMMSE scores 6 years later, net of potential confounding effects of baseline covariates. Sensitivity analyses found that regression coefficients of mMMSE scores on transient loneliness were statistically significant and relatively stable across samples with various levels of cognitive function. In contrast, coefficients of mMMSE scores on chronic loneliness were statistically significant only among samples with normal cognitive function and the absolute values of these coefficients increased with the degree of cognitive health of the analytic sample. In the sample with mMMSE greater than or equal to 21, the coefficient of chronic loneliness was 2.59 times as large as that of transient loneliness (-1.017 versus -0.392). Both transient and chronic loneliness are significant predictors of cognitive decline in OAs. Relative to transient loneliness, chronic loneliness has more pronounced negative effects on the brain health of OAs. Copyright © 2016 American Association for Geriatric Psychiatry. Published by Elsevier Inc. All rights reserved.

Investigation of thermal-fluid mechanical characteristics of the Capillary Pump Loop

NASA Technical Reports Server (NTRS)

Kiper, Ali M.

1991-01-01

The main purpose is the experimental and analytical study of behavior of the Capillary Pump Loop (CPL) heat pipe system during the transient mode of operating by applying a step heat pulse to one or more evaporators. Prediction of the CPL behavior when subjected to pulse heat loading requires further study before the transient response of CPL system can be fully understood. The following tasks are discussed: (1) exploratory testing of a CPL heat pipe for transient operational conditions which could generate the type of oscillatory inlet temperature behavior observed in an earlier testing of NASA/GSFC CPL-2 heat pipe system; (2) analytical investigation of the CPL inlet section temperature oscillations; (3) design, construction and testing of a bench-top CPL test system for study of the CPL transient operation; and (4) transient analysis of a CPL heat pipe by applying a step power input to the evaporators.

A transient laboratory method for determining the hydraulic properties of 'tight' rocks-I. Theory

USGS Publications Warehouse

Hsieh, P.A.; Tracy, J.V.; Neuzil, C.E.; Bredehoeft, J.D.; Silliman, Stephen E.

1981-01-01

Transient pulse testing has been employed increasingly in the laboratory to measure the hydraulic properties of rock samples with low permeability. Several investigators have proposed a mathematical model in terms of an initial-boundary value problem to describe fluid flow in a transient pulse test. However, the solution of this problem has not been available. In analyzing data from the transient pulse test, previous investigators have either employed analytical solutions that are derived with the use of additional, restrictive assumptions, or have resorted to numerical methods. In Part I of this paper, a general, analytical solution for the transient pulse test is presented. This solution is graphically illustrated by plots of dimensionless variables for several cases of interest. The solution is shown to contain, as limiting cases, the more restrictive analytical solutions that the previous investigators have derived. A method of computing both the permeability and specific storage of the test sample from experimental data will be presented in Part II. ?? 1981.

Review of Transient Testing of Fast Reactor Fuels in the Transient REActor Test Facility (TREAT)

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

Jensen, C.; Wachs, D.; Carmack, J.

The restart of the Transient REActor Test (TREAT) facility provides a unique opportunity to engage the fast reactor fuels community to reinitiate in-pile experimental safety studies. Historically, the TREAT facility played a critical role in characterizing the behavior of both metal and oxide fast reactor fuels under off-normal conditions, irradiating hundreds of fuel pins to support fast reactor fuel development programs. The resulting test data has provided validation for a multitude of fuel performance and severe accident analysis computer codes. This paper will provide a review of the historical database of TREAT experiments including experiment design, instrumentation, test objectives, andmore » salient findings. Additionally, the paper will provide an introduction to the current and future experiment plans of the U.S. transient testing program at TREAT.« less

Continuation of surge life of transient voltage suppressor

NASA Technical Reports Server (NTRS)

Clark, O. M.

1977-01-01

Efforts expended in testing, analyzing and the development of a meaningful definition of the mean number of peak pulses before failure (mp2bf) levels of a family of transient voltage suppressor devices were documented. Tests were done to determine the ability of the transient suppressor to effectively and reliably protect against severe short term, millisecond range, and transient voltages of the types resulting from inductive load switching and induced lightning. Existing pulse testing instrumentation was utilized, interfaced to an automatic sequencing test rack accommodating up to 50 devices. Tests were performed in step stress increments of 25% beginning at 25% and extending thru 100% rated I(pp) for each voltage category. The four voltage types test were the 6.8V, 33V, 91V, and 190V. Engineering efforts addressed the problem of improving the reliability of the 190V types.

Experimental transient and permanent deformation studies of steel-sphere-impacted or impulsively-loaded aluminum beams with clamped ends

NASA Technical Reports Server (NTRS)

Witmer, E. A.

1975-01-01

The sheet explosive loading technique (SELT) was employed to obtain elastic-plastic, large-deflection transient and/or permanent strain data on simple well-defined structural specimens and materials: initially-flat 6061-T651 aluminum beams with both ends ideally clamped via integral construction. The SELT loading technique was chosen since it is both convenient and provides forcing function information of small uncertainty. These data will be useful for evaluating pertinent structural response prediction methods. A second objective was to obtain high-quality transient-strain data for a well-defined structural/material model subjected to impact by a rigid body of known mass, impact velocity, and geometry; large-deflection, elastic-plastic transient response conditions are of primary interest. The beam with both ends clamped and a steel sphere as the impacting body were chosen. The steel sphere was launched vertically by explosive propulsion to achieve various desired impact velocities. The sphere/beam impact tests resulted in producing a wide range of structural responses and permanent deformations, including rupture of the beam from excessive structural response in two cases. The transient and permanent strain data as well as the permanent deflection data obtained are of high quality and should be useful for checking and evaluating methods for predicting the responses of simple 2-d structures to fragment (sphere) impact. Transient strain data very close to the point of impact were not obtained over as long a time as desirable because the gage(s) in that region became detached during the transient response.

High incidence of defective high-shear platelet function among platelet donors.

PubMed

Harrison, Paul; Segal, Helen; Furtado, Charlene; Verjee, Salim; Sukhu, Kampta; Murphy, Michael F

2004-05-01

Because single-donor plateletpheresis concentrates now account for a large percentage of PLT concentrates, the PLT quality of individual donations is increasingly important. There has been little previous work on PLT function in blood donors. The aim of this study was to investigate the prevalence of defective PLT function among 100 healthy UK PLT donors on 3 consecutive donation days. Citrated blood samples were taken before plateletpheresis. High-shear PLT function testing was performed by a PLT function analyzer (PFA-100, Dade Behring), within both collagen-ADP (CADP) and collagen-epinephrine (CEPI) cartridges. Sixteen percent of PLT donors (mainly over the 3 donating days) had prolonged CEPI closure times (CTs) only, indicative of an aspirin-like pattern; 9 percent had a severe defect with prolonged CEPI CTs between 200 and 300 seconds, and 4 percent had maximal CEPI CTs of greater than 300 seconds. The majority of prolonged CEPI CTs appeared transient in nature. PLT dysfunction as detected by the PFA-100 is surprisingly common within a voluntary PLT donor population. The majority of CEPI defects appeared transient in nature and are indicative of surreptitious intake of cyclooxygenase inhibitors (e.g., aspirin). Identification of defective PLT function within donors would provide a simple means to eradicate defective PLTs from being clinically utilized.

Analysis of the TREAT LEU Conceptual Design

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

Connaway, H. M.; Kontogeorgakos, D. C.; Papadias, D. D.

2016-03-01

Analyses were performed to evaluate the performance of the low enriched uranium (LEU) conceptual design fuel for the conversion of the Transient Reactor Test Facility (TREAT) from its current highly enriched uranium (HEU) fuel. TREAT is an experimental nuclear reactor designed to produce high neutron flux transients for the testing of reactor fuels and other materials. TREAT is currently in non-operational standby, but is being restarted under the U.S. Department of Energy’s Resumption of Transient Testing Program. The conversion of TREAT is being pursued in keeping with the mission of the Department of Energy National Nuclear Security Administration’s Material Managementmore » and Minimization (M3) Reactor Conversion Program. The focus of this study was to demonstrate that the converted LEU core is capable of maintaining the performance of the existing HEU core, while continuing to operate safely. Neutronic and thermal hydraulic simulations have been performed to evaluate the performance of the LEU conceptual-design core under both steady-state and transient conditions, for both normal operation and reactivity insertion accident scenarios. In addition, ancillary safety analyses which were performed for previous LEU design concepts have been reviewed and updated as-needed, in order to evaluate if the converted LEU core will function safely with all existing facility systems. Simulations were also performed to evaluate the detailed behavior of the UO 2-graphite fuel, to support future fuel manufacturing decisions regarding particle size specifications. The results of these analyses will be used in conjunction with work being performed at Idaho National Laboratory and Los Alamos National Laboratory, in order to develop the Conceptual Design Report project deliverable.« less

Elements in the transcriptional regulatory region flanking herpes simplex virus type 1 oriS stimulate origin function.

PubMed

Wong, S W; Schaffer, P A

1991-05-01

Like other DNA-containing viruses, the three origins of herpes simplex virus type 1 (HSV-1) DNA replication are flanked by sequences containing transcriptional regulatory elements. In a transient plasmid replication assay, deletion of sequences comprising the transcriptional regulatory elements of ICP4 and ICP22/47, which flank oriS, resulted in a greater than 80-fold decrease in origin function compared with a plasmid, pOS-822, which retains these sequences. In an effort to identify specific cis-acting elements responsible for this effect, we conducted systematic deletion analysis of the flanking region with plasmid pOS-822 and tested the resulting mutant plasmids for origin function. Stimulation by cis-acting elements was shown to be both distance and orientation dependent, as changes in either parameter resulted in a decrease in oriS function. Additional evidence for the stimulatory effect of flanking sequences on origin function was demonstrated by replacement of these sequences with the cytomegalovirus immediate-early promoter, resulting in nearly wild-type levels of oriS function. In competition experiments, cotransfection of cells with the test plasmid, pOS-822, and increasing molar concentrations of a competitor plasmid which contained the ICP4 and ICP22/47 transcriptional regulatory regions but lacked core origin sequences resulted in a significant reduction in the replication efficiency of pOS-822, demonstrating that factors which bind specifically to the oriS-flanking sequences are likely involved as auxiliary proteins in oriS function. Together, these studies demonstrate that trans-acting factors and the sites to which they bind play a critical role in the efficiency of HSV-1 DNA replication from oriS in transient-replication assays.

Clinical course of infants with congenital heart disease who developed thyroid dysfunction within 100 days

PubMed Central

Lee, Hye Jin; Yu, Hyeoh Won; Kim, Gi Beom; Shin, Choong Ho; Yang, Sei Won

2017-01-01

Purpose We investigated the clinical course of infants with congenital heart disease (CHD) who experienced thyroid dysfunction within 100 days of birth. Methods We performed retrospective medical reviews of 54 CHD patients (24 male patients) who underwent a thyroid function test (TFT) between January 2007 and July 2016. Data were collected on birth history, diagnosis of CHD, underlying chromosomal or genetic abnormalities, medication history, surgery, ventilator care, and exposure to iodine contrast media (ICM). Results of neonatal screening tests (NSTs) and TFTs were reviewed. Results A total of 36 patients (29 transient, 7 permanent) showed thyroid dysfunction. Among the seven patients with permanent hypothyroidism, three had an underlying syndrome, three showed abnormal NST results, and one was admitted to the intensive care unit for macroglossia and feeding cyanosis. We found that infants with transient thyroid dysfunction had a lower birth weight and were more commonly exposed to thyroid disrupting medication and/or ICM. However, these risk factors were not significant. A total of 8 patients with a history of ICM exposure showed thyroid dysfunction. Excluding 3 patients with elevated thyroid stimulating hormone before ICM exposure, 5 patients recovered from transient thyroid dysfunction. Conclusions We observed thyroid dysfunction in two-thirds of CHD infants (53.7% transient, 13.0% permanent) who had risk factors and received TFT screening within 100 days, despite normal NSTs. Further studies with larger sample sizes are required to revise the criteria for TFT screening in CHD infants. PMID:29301186

Pulmonary function in infectious mononucleosis.

PubMed

Morgan, E J; Altmeyer, R; Khakoo, R; Lapp, N L

1982-06-01

Infectious mononucleosis (IM) is common among students. These patients often complain of fatigue and dyspnea. To determine whether IM alters respiratory function, we performed spirometric, single-breath diffusing capacity, and maximal static respiratory pressure tests on seven patients with symptoms of IM. These studies were repeated two weeks later and the respiratory pressures were repeated five months later. Each patient served as his own control. Pulmonary function was normal except for respiratory pressures, which were initially low. These pressures, still low after two weeks, improved significantly after five months. We concluded that IM is associated with transient respiratory muscle weakness.

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

Jensen, Colby B.; Folsom, Charles P.; Davis, Cliff B.

Experimental testing in the Multi-Static Environment Rodlet Transient Test Apparatus (SERTTA) will lead the rebirth of transient fuel testing in the United States as part of the Accident Tolerant Fuels (ATF) progam. The Multi-SERTTA is comprised of four isolated pressurized environments capable of a wide variety of working fluids and thermal conditions. Ultimately, the TREAT reactor as well as the Multi-SERTTA test vehicle serve the purpose of providing desired thermal-hydraulic boundary conditions to the test specimen. The initial ATF testing in TREAT will focus on reactivity insertion accident (RIA) events using both gas and water environments including typical PWR operatingmore » pressures and temperatures. For the water test environment, a test configuration is envisioned using the expansion tank as part of the gas-filled expansion volume seen by the test to provide additional pressure relief. The heat transfer conditions during the high energy power pulses of RIA events remains a subject of large uncertainty and great importance for fuel performance predictions. To support transient experiments, the Multi-SERTTA vehicle has been modeled using RELAP5 with a baseline test specimen composed of UO2 fuel in zircaloy cladding. The modeling results show the influence of the designs of the specimen, vehicle, and transient power pulses. The primary purpose of this work is to provide input and boundary conditions to fuel performance code BISON. Therefore, studies of parameters having influence on specimen performance during RIA transients are presented including cladding oxidation, power pulse magnitude and width, cladding-to-coolant heat fluxes, fuel-to-cladding gap, transient boiling effects (modified CHF values), etc. The results show the great flexibility and capacity of the TREAT Multi-SERTTA test vehicle to provide testing under a wide range of prototypic thermal-hydraulic conditions as never done before.« less

Characterizing SI Engine Transient Fuel Consumption in ...

EPA Pesticide Factsheets

Examine typical transient engine operation encountered over the EPA's vehicle and engine testing drive cycles to characterize that transient fuel usage, and then describe the changes made to ALPHA to better model transient engine operation. To present an approach to capture dynamic fuel consumption during engine transients and then implement these identified characteristics in ALPHA.

The relationship between transient and persistent worsening renal function and mortality in patients with acute decompensated heart failure.

PubMed

Aronson, Doron; Burger, Andrew J

2010-07-01

Worsening renal function (WRF) is an ominous complication in patients with acute heart failure syndrome (AHFS). Few data are available with regard to the clinical implications of transient versus persistent WRF in this setting. We studied 467 patients with AHFS and creatinine measurements at baseline and on days 2, 5, 14, and 30. WRF (>/= 0.5 mg/dL increase in serum creatinine above baseline at any time point) was defined as persistent when serum creatinine remained >/= 0.5 mg/dL above baseline throughout day 30, and transient when creatinine levels subsequently decreased to < 0.5 mg/dL above baseline. WRF occurred in 115 patients, and was transient in 39 patients (33.9%). The 6-month mortality rates were 17.3%, 20.5%, and 46.1% in patients without WRF, transient WRF, and persistent WRF, respectively. In a multivariable Cox model, compared with patients with stable renal function, the adjusted hazard ratio for mortality was 0.8 (95% CI 0.4-1.7; P = .58) in patients with transient WRF and 3.2 (95% CI 2.1-5.0; P < .0001) in patients with persistent WRF. Transient WRF is frequent among patients with AHFS. Whereas persistent WRF portends increased mortality, transient WRF appears to be associated with a better outcome as compared with persistent renal failure. Copyright 2010 Elsevier Inc. All rights reserved.

Deconvolution of noisy transient signals: a Kalman filtering application

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

Candy, J.V.; Zicker, J.E.

The deconvolution of transient signals from noisy measurements is a common problem occuring in various tests at Lawrence Livermore National Laboratory. The transient deconvolution problem places atypical constraints on algorithms presently available. The Schmidt-Kalman filter, a time-varying, tunable predictor, is designed using a piecewise constant model of the transient input signal. A simulation is developed to test the algorithm for various input signal bandwidths and different signal-to-noise ratios for the input and output sequences. The algorithm performance is reasonable.

Measurement of Turbine Engine Transient Airflow in Ground Test Facilities

DTIC Science & Technology

1980-08-01

REPORT NUMBER 12 GOVT ACCESSION NO. A E D C - T R - 8 0 - 2 1 L 6. T I T L E (aqd Subl l l |e ) MEASUREMENT OF TURBINE ENGINE TRANSIENT AIRFLOW IN...21 ILLUSTRATIONS Figure !. Direct-Connect Turbine Engine Test Cell Installation...26 3. Turbine Engine Transient Airflow Simulator (TETAS) . . . . . . . . . . . . . . . . . . . . . . . . . 27 4

Effect of Electroconvulsive Therapy on Cognitive Functions of Rats with Depression-Like Disorders Induced by Ultrasound Exposure.

PubMed

Ushakova, V M; Zubkov, E A; Morozova, A Y; Gorlova, A V; Pavlov, D A; Inozemtsev, A N; Chekhonin, V P

2017-09-01

We studied the effect of electroconvulsive therapy on cognitive functions in rats with depression-like disorder caused by exposure to ultrasound of varying frequency (20-45 kHz). Object recognition and Morris water-maze tests revealed no negative effects of the therapy on memory. Moreover, positive effect of therapy was demonstrated that manifested in amelioration of memory disturbances in depression-like disorders in these behavioral tests. The results of this study do not support the idea about side effects of electroconvulsive therapy, in particular, development of transient amnesia, and are a prerequisite for a more thorough study of internal mechanisms of the effect of the therapy on cognitive sphere.

Multi-Physics Simulation of TREAT Kinetics using MAMMOTH

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

DeHart, Mark; Gleicher, Frederick; Ortensi, Javier

With the advent of next generation reactor systems and new fuel designs, the U.S. Department of Energy (DOE) has identified the need for the resumption of transient testing of nuclear fuels. DOE has decided that the Transient Reactor Test Facility (TREAT) at Idaho National Laboratory (INL) is best suited for future testing. TREAT is a thermal neutron spectrum nuclear test facility that is designed to test nuclear fuels in transient scenarios. These specific fuels transient tests range from simple temperature transients to full fuel melt accidents. The current TREAT core is driven by highly enriched uranium (HEU) dispersed in amore » graphite matrix (1:10000 U-235/C atom ratio). At the center of the core, fuel is removed allowing for the insertion of an experimental test vehicle. TREAT’s design provides experimental flexibility and inherent safety during neutron pulsing. This safety stems from the graphite in the driver fuel having a strong negative temperature coefficient of reactivity resulting from a thermal Maxwellian shift with increased leakage, as well as graphite acting as a temperature sink. Air cooling is available, but is generally used post-transient for heat removal. DOE and INL have expressed a desire to develop a simulation capability that will accurately model the experiments before they are irradiated at the facility, with an emphasis on effective and safe operation while minimizing experimental time and cost. At INL, the Multi-physics Object Oriented Simulation Environment (MOOSE) has been selected as the model development framework for this work. This paper describes the results of preliminary simulations of a TREAT fuel element under transient conditions using the MOOSE-based MAMMOTH reactor physics tool.« less

EXPERIMENTAL STUDIES OF TRANSIENT EFFECTS IN FAST REACTOR FUELS. SERIES I. UO$sub 2$ IRRADIATIONS

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

Field, J.H.

1962-11-15

An experimental program to evaluate the performance of FCR and EFCR fuel during transient operation is outlined, and the initial series of tests are described in some detail. Test results from five experiments in the TREAT reactor, using 1-in. OD SS-clad UO/sub 2/ fuel specimens, are compared with regard to fuel temperatures, mechanical integrity, and post-irradiation appearance. Incipient fuel pin failure limits for transients are identified with maximum fuel temperatures in the range of 7000 deg F. Multiple transient damage to the cladding is likely for transients above the melting point of the fuel. (auth)

Design and calibration of a novel transient radiative heat flux meter for a spacecraft thermal test

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

Sheng, Chunchen; Hu, Peng, E-mail: hupeng@ustc.edu.cn; Cheng, Xiaofang

2016-06-15

Radiative heat flux measurement is significantly important for a spacecraft thermal test. To satisfy the requirements of both high accuracy and fast response, a novel transient radiative heat flux meter was developed. Its thermal receiver consists of a central thermal receiver and two thermal guarded annular plates, which ensure the temperature distribution of the central thermal receiver to be uniform enough for reasonably applying lumped heat capacity method in a transient radiative heat flux measurement. This novel transient radiative heat flux meter design can also take accurate measurements regardless of spacecraft surface temperature and incident radiation spectrum. The measurement principlemore » was elaborated and the coefficients were calibrated. Experimental results from testing a blackbody furnace and an Xenon lamp show that this novel transient radiative heat flux meter can be used to measure transient radiative heat flux up to 1400 W/m{sup 2} with high accuracy and the response time of less than 10 s.« less

Neutronics and Transient Calculations for the Conversion of the Transient Reactor Rest Facility (TREAT)

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

Kontogeorgakos, Dimitrios C.; Connaway, Heather M.; Papadias, Dionissios D.

2015-01-01

The Transient Reactor Test Facility (TREAT) is a graphite-reflected, graphitemoderated, and air-cooled reactor fueled with 93.1% enriched UO2 particles dispersed in graphite, with a carbon-to-235U ratio of ~10000:1. TREAT was used to simulate accident conditions by subjecting fuel test samples placed at the center of the core to high energy transient pulses. The transient pulse production is based on the core’s selflimiting nature due to the negative reactivity feedback provided by the fuel graphite as the core temperature rises. The analysis of the conversion of TREAT to low enriched uranium (LEU) is currently underway. This paper presents the analytical methodsmore » used to calculate the transient performance of TREAT in terms of power pulse production and resulting peak core temperatures. The validation of the HEU neutronics TREAT model, the calculation of the temperature distribution and the temperature reactivity feedback as well as the number of fissions generated inside fuel test samples are discussed.« less

Transient hypogonadotropic hypogonadism in an amateur kickboxer after head trauma.

PubMed

Tanriverdi, F; Unluhizarci, K; Selcuklu, A; Casanueva, F F; Kelestimur, F

2007-02-01

Traumatic brain injury (TBI) is a frequent health problem and increased prevalence of neurendocrine dysfunction in patients with TBI has been reported. Sports injuries and particularly boxing may result in pituitary dysfunction. However, transient hypogonadotropic hypogonadism after an acute head trauma due to boxing and/or kickboxing has not been defined yet. We describe the case of a 20-yr-old male amateur kickboxer who was admitted to hospital complaining of decreased libido and impotence 2 weeks after an intensive bout. Basal hormone levels were compatible with mild hyperprolactinemia and hypogonadotpopic hypogonadism. GH axis was evaluated by GHRH+GHRP-6 test and peak GH level was within normal reference range. Three months later his complaints improved and abnormalities in basal hormone levels normalized. He was also re-evaluated 9 months after the first evaluation; basal hormone levels were within normal ranges and he had no complaints. In conclusion acute head trauma due to kickboxing may cause transient gonadotropin deficiency. Therefore, screening the pituitary functions of sportsmen dealing with combative sports is crucial.

Single Event Transients in Voltage Regulators for FPGA Power Supply Applications

NASA Technical Reports Server (NTRS)

Poivey, Christian; Sanders, Anthony; Kim, Hak; Phan, Anthony; Forney, Jim; LaBel, Kenneth A.; Karsh, Jeremy; Pursley, Scott; Kleyner, Igor; Katz, Richard

2006-01-01

As with other bipolar analog devices, voltage regulators are known to be sensitive to single event transients (SET). In typical applications, large output capacitors are used to provide noise immunity. Therefore, since SET amplitude and duration are generally small, they are often of secondary importance due to this capacitance filtering. In low voltage applications, however, even small SET are a concern. Over-voltages may cause destructive conditions. Under-voltages may cause functional interrupts and may also trigger electrical latchup conditions. In addition, internal protection circuits which are affected by load as well as internal thermal effects can also be triggered from heavy ions, causing dropouts or shutdown ranging from milliseconds to seconds. In the case of FPGA power supplies applications, SETS are critical. For example, in the case of Actel FPGA RTAX family, core power supply voltage is 1.5V. Manufacturer specifies an absolute maximum rating of 1.6V and recommended operating conditions between 1.425V and 1.575V. Therefore, according to the manufacturer, any transient of amplitude greater than 75 mV can disrupt normal circuit functions, and overvoltages greater than 100 mV may damage the FPGA. We tested five low dropout voltage regulators for SET sensitivity under a large range of circuit application conditions.

Novel Material Systems and Methodologies for Transient Thermal Management

NASA Technical Reports Server (NTRS)

Oliva-Buisson, Yvette J.

2014-01-01

Development of multifunctional and thermally switchable systems to address reduced mass and components, and tailored for both structural and transient thermal applications. Active, passive, and novel combinations of the two functional approaches are being developed along two lines of research investigation: switchable systems and transient heat spreading. The approach is to build in thermal functionality to structural elements to lay the foundation for a revolution in the way high energy space systems are designed.

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

Brown, Nicholas R.; Carlsen, Brett W.; Dixon, Brent W.

Dynamic fuel cycle simulation tools are intended to model holistic transient nuclear fuel cycle scenarios. As with all simulation tools, fuel cycle simulators require verification through unit tests, benchmark cases, and integral tests. Model validation is a vital aspect as well. Although compara-tive studies have been performed, there is no comprehensive unit test and benchmark library for fuel cycle simulator tools. The objective of this paper is to identify the must test functionalities of a fuel cycle simulator tool within the context of specific problems of interest to the Fuel Cycle Options Campaign within the U.S. Department of Energy smore » Office of Nuclear Energy. The approach in this paper identifies the features needed to cover the range of promising fuel cycle options identified in the DOE-NE Fuel Cycle Evaluation and Screening (E&S) and categorizes these features to facilitate prioritization. Features were categorized as essential functions, integrating features, and exemplary capabilities. One objective of this paper is to propose a library of unit tests applicable to each of the essential functions. Another underlying motivation for this paper is to encourage an international dialog on the functionalities and standard test methods for fuel cycle simulator tools.« less

Semantic acquisition without memories: evidence from transient global amnesia.

PubMed

Guillery, B; Desgranges, B; Katis, S; de la Sayette, V; Viader, F; Eustache, F

2001-12-04

Transient global amnesia (TGA), characterised by a profound anterograde amnesia, is a model of interest to study the acquisition of novel meanings independent of episodic functioning. Three patients were tested during a TGA attack, two in the early recovery phase and the third during the acute phase of TGA, with a semantic priming task involving a restructuring process of conceptual knowledge. During TGA, all patients demonstrated priming effects. Results obtained the day after the episode with the same task showed that these effects persisted at least one day. Episodic memory seems not to be critical for the formation of novel connections among unrelated semantic representations, in accordance with Tulving's model of memory, i.e. episodic memory is not necessary for the acquisition of semantic information.

Four RNA families with functional transient structures

PubMed Central

Zhu, Jing Yun A; Meyer, Irmtraud M

2015-01-01

Protein-coding and non-coding RNA transcripts perform a wide variety of cellular functions in diverse organisms. Several of their functional roles are expressed and modulated via RNA structure. A given transcript, however, can have more than a single functional RNA structure throughout its life, a fact which has been previously overlooked. Transient RNA structures, for example, are only present during specific time intervals and cellular conditions. We here introduce four RNA families with transient RNA structures that play distinct and diverse functional roles. Moreover, we show that these transient RNA structures are structurally well-defined and evolutionarily conserved. Since Rfam annotates one structure for each family, there is either no annotation for these transient structures or no such family. Thus, our alignments either significantly update and extend the existing Rfam families or introduce a new RNA family to Rfam. For each of the four RNA families, we compile a multiple-sequence alignment based on experimentally verified transient and dominant (dominant in terms of either the thermodynamic stability and/or attention received so far) RNA secondary structures using a combination of automated search via covariance model and manual curation. The first alignment is the Trp operon leader which regulates the operon transcription in response to tryptophan abundance through alternative structures. The second alignment is the HDV ribozyme which we extend to the 5′ flanking sequence. This flanking sequence is involved in the regulation of the transcript's self-cleavage activity. The third alignment is the 5′ UTR of the maturation protein from Levivirus which contains a transient structure that temporarily postpones the formation of the final inhibitory structure to allow translation of maturation protein. The fourth and last alignment is the SAM riboswitch which regulates the downstream gene expression by assuming alternative structures upon binding of SAM. All transient and dominant structures are mapped to our new alignments introduced here. PMID:25751035

Four RNA families with functional transient structures.

PubMed

Zhu, Jing Yun A; Meyer, Irmtraud M

2015-01-01

Protein-coding and non-coding RNA transcripts perform a wide variety of cellular functions in diverse organisms. Several of their functional roles are expressed and modulated via RNA structure. A given transcript, however, can have more than a single functional RNA structure throughout its life, a fact which has been previously overlooked. Transient RNA structures, for example, are only present during specific time intervals and cellular conditions. We here introduce four RNA families with transient RNA structures that play distinct and diverse functional roles. Moreover, we show that these transient RNA structures are structurally well-defined and evolutionarily conserved. Since Rfam annotates one structure for each family, there is either no annotation for these transient structures or no such family. Thus, our alignments either significantly update and extend the existing Rfam families or introduce a new RNA family to Rfam. For each of the four RNA families, we compile a multiple-sequence alignment based on experimentally verified transient and dominant (dominant in terms of either the thermodynamic stability and/or attention received so far) RNA secondary structures using a combination of automated search via covariance model and manual curation. The first alignment is the Trp operon leader which regulates the operon transcription in response to tryptophan abundance through alternative structures. The second alignment is the HDV ribozyme which we extend to the 5' flanking sequence. This flanking sequence is involved in the regulation of the transcript's self-cleavage activity. The third alignment is the 5' UTR of the maturation protein from Levivirus which contains a transient structure that temporarily postpones the formation of the final inhibitory structure to allow translation of maturation protein. The fourth and last alignment is the SAM riboswitch which regulates the downstream gene expression by assuming alternative structures upon binding of SAM. All transient and dominant structures are mapped to our new alignments introduced here.

Intelligent transient transitions detection of LRE test bed

NASA Astrophysics Data System (ADS)

Zhu, Fengyu; Shen, Zhengguang; Wang, Qi

2013-01-01

Health Monitoring Systems is an implementation of monitoring strategies for complex systems whereby avoiding catastrophic failure, extending life and leading to improved asset management. A Health Monitoring Systems generally encompasses intelligence at many levels and sub-systems including sensors, actuators, devices, etc. In this paper, a smart sensor is studied, which is use to detect transient transitions of liquid-propellant rocket engines test bed. In consideration of dramatic changes of variable condition, wavelet decomposition is used to work real time in areas. Contrast to traditional Fourier transform method, the major advantage of adding wavelet analysis is the ability to detect transient transitions as well as obtaining the frequency content using a much smaller data set. Historically, transient transitions were only detected by offline analysis of the data. The methods proposed in this paper provide an opportunity to detect transient transitions automatically as well as many additional data anomalies, and provide improved data-correction and sensor health diagnostic abilities. The developed algorithms have been tested on actual rocket test data.

Prevalence and factors associated with the presence of abnormal function liver tests in patients with ulcerative colitis.

PubMed

Yamamoto-Furusho, Jesús K; Sánchez-Osorio, Magdalena; Uribe, Misael

2010-01-01

To investigate the prevalence of abnormal function liver tests and risk factors associated with their development in Mexican patients with UC. A total of 200 patients with confirmed diagnosis of UC were evaluated prospectively during a one year period from January 1, 2007 to December 31, 2008. A total of 94 females and 106 males patients with UC were analyzed. The age at diagnosis was 31.4 ± 13.2 years and the mean of disease duration was 6.7 ± 5.2 years. We found a high prevalence of abnormal function livers tests in 40% of UC patients. The pattern of abnormal function liver test was hepatitis in 70%, cholestatic (20%) and mixed (10%). The most common cause of abnormal function liver test was transient elevation in 50 patients (63%) followed by fatty liver disease (11.2%), primary sclerosing cholangitis (6.3%), drug-toxicity (6%) and others (13.5%) including chronic hepatitis C, total parenteral nutrition, granulomatous and ischemic hepatitis. In the multivariate logistic regression model, active disease, colectomy and abdominal sepsis were factors that persisted associated with the development of abnormal liver tests in UC patients. A high prevalence of abnormal function liver tests (40%) was found in Mexican UC patients is likely to be related to active disease, colectomy and the presence of sepsis.

Effects of Kaempferia parviflora Wall. Ex. Baker and sildenafil citrate on cGMP level, cardiac function, and intracellular Ca2+ regulation in rat hearts.

PubMed

Weerateerangkul, Punate; Palee, Siripong; Chinda, Kroekkiat; Chattipakorn, Siriporn C; Chattipakorn, Nipon

2012-09-01

Although Kaempferia parviflora extract (KPE) and its flavonoids have positive effects on the nitric oxide (NO) signaling pathway, its mechanisms on the heart are still unclear. Because our previous studies demonstrated that KPE decreased defibrillation efficacy in swine similar to that of sildenafil citrate, the phosphodiesterase-5 inhibitor, it is possible that KPE may affect the cardiac NO signaling pathway. In the present study, the effects of KPE and sildenafil citrate on cyclic guanosine monophosphate (cGMP) level, modulation of cardiac function, and Ca transients in ventricular myocytes were investigated. In a rat model, cardiac cGMP level, cardiac function, and Ca transients were measured before and after treatment with KPE and sildenafil citrate. KPE significantly increased the cGMP level and decreased cardiac function and Ca transient. These effects were similar to those found in the sildenafil citrate-treated group. Furthermore, the nonspecific NOS inhibitor could abolish the effects of KPE and sildenafil citrate on Ca transient. KPE has positive effect on NO signaling in the heart, resulting in an increased cGMP level, similar to that of sildenafil citrate. This effect was found to influence the physiology of normal heart via the attenuation of cardiac function and the reduction of Ca transient in ventricular myocytes.

Electronically controlled mechanical seal for aerospace applications--Part 2: Transient tests

NASA Technical Reports Server (NTRS)

Wolff, Paul J.; Salant, Richard F.

1995-01-01

An electronically controlled mechanical seal for use as the purge gas seal in a liquid oxygen turbopump has been fabricated and tested under transient operating conditions. The thickness of the lubricating film is controlled by adjusting the coning of the carbon face. This is accomplished by applying a voltage to a piezoelectric actuator to which the carbon face is bonded. The seal has been operated with a closed-loop control system that utilizes either the leakage rate or seal face temperature as the feedback. Both speed and pressure transients have been imposed on the seal. The transient tests have demonstrated that the seal is capable of maintaing low leakage rates while limiting face temperatures.

Beam-Switch Transient Effects in the RF Path of the ICAPA Receive Phased Array Antenna

NASA Technical Reports Server (NTRS)

Sands, O. Scott

2003-01-01

When the beam of a Phased Array Antenna (PAA) is switched from one pointing direction to another, transient effects in the RF path of the antenna are observed. Testing described in the report has revealed implementation-specific transient effects in the RF channel that are associated with digital clocking pulses that occur with transfer of data from the Beam Steering Controller (BSC) to the digital electronics of the PAA under test. The testing described here provides an initial assessment of the beam-switch phenomena by digitally acquiring time series of the RF communications channel, under CW excitation, during the period of time that the beam switch transient occurs. Effects are analyzed using time-frequency distributions and instantaneous frequency estimation techniques. The results of tests conducted with CW excitation supports further Bit-Error-Rate (BER) testing of the PAA communication channel.

Transient hypothyroidism after iodine-131 therapy for Grave's disease.

PubMed

Gómez, N; Gómez, J M; Orti, A; Gavaldà, L; Villabona, C; Leyes, P; Soler, J

1995-09-01

We studied 355 patients with Grave's disease to characterize transient hypothyroidism and its prognostic value following 131I therapy. The patients received therapeutic 131I treatment as follows: 333 received a dose < 10 mCi (6.6 +/- 1.9 mCi) and 22 received a dose > 10 mCi (12.8 +/- 2.9 mCi). Diagnosis of transient hypothyroidism was based on low T4, regardless of TSH within the first year after 131I followed by recovery of T4 and normal TSH. After administration of < 10 mCi 131I, 40 patients developed transient hypothyroidism during the first year; transient hypothyroidism was symptomatic in 15. There was no transient hypothyroidism after high doses (> 10 mCi) of 131I. Iodine-131 uptake > 70% at 2 hr before treatment was a risk factor for developing transient hypothyroidism (Odds ratio 2.8, 95% confidence interval 0.9-9.4). At diagnosis of transient hypothyroidism, basal TSH levels were high (51%), normal (35%) or low (14%); therefore, the transient hypothyroidism was not centralized. If hypothyroidism developed during the first 6 mo after basal TSH > 45 mU/liter ruled out transient hypothyroidism. The development of transient hypothyroidism and its hormonal pattern did not influence long-term thyroid function. Since no prognostic factors reliably predicted transient hypothyroidism before 131I or at the time of diagnosis, if hypothyroidism appears within the first months after 131I, the reevaluation of thyroid function later is warranted to avoid unnecessary chronic replacement therapy.

Large Eddy Simulation of Transient Flow, Solidification, and Particle Transport Processes in Continuous-Casting Mold

NASA Astrophysics Data System (ADS)

Liu, Zhongqiu; Li, Linmin; Li, Baokuan; Jiang, Maofa

2014-07-01

The current study developed a coupled computational model to simulate the transient fluid flow, solidification, and particle transport processes in a slab continuous-casting mold. Transient flow of molten steel in the mold is calculated using the large eddy simulation. An enthalpy-porosity approach is used for the analysis of solidification processes. The transport of bubble and non-metallic inclusion inside the liquid pool is calculated using the Lagrangian approach based on the transient flow field. A criterion of particle entrapment in the solidified shell is developed using the user-defined functions of FLUENT software (ANSYS, Inc., Canonsburg, PA). The predicted results of this model are compared with the measurements of the ultrasonic testing of the rolled steel plates and the water model experiments. The transient asymmetrical flow pattern inside the liquid pool exhibits quite satisfactory agreement with the corresponding measurements. The predicted complex instantaneous velocity field is composed of various small recirculation zones and multiple vortices. The transport of particles inside the liquid pool and the entrapment of particles in the solidified shell are not symmetric. The Magnus force can reduce the entrapment ratio of particles in the solidified shell, especially for smaller particles, but the effect is not obvious. The Marangoni force can play an important role in controlling the motion of particles, which increases the entrapment ratio of particles in the solidified shell obviously.

Identification of fuel cycle simulator functionalities for analysis of transition to a new fuel cycle

DOE PAGES

Brown, Nicholas R.; Carlsen, Brett W.; Dixon, Brent W.; ...

2016-06-09

Dynamic fuel cycle simulation tools are intended to model holistic transient nuclear fuel cycle scenarios. As with all simulation tools, fuel cycle simulators require verification through unit tests, benchmark cases, and integral tests. Model validation is a vital aspect as well. Although compara-tive studies have been performed, there is no comprehensive unit test and benchmark library for fuel cycle simulator tools. The objective of this paper is to identify the must test functionalities of a fuel cycle simulator tool within the context of specific problems of interest to the Fuel Cycle Options Campaign within the U.S. Department of Energy smore » Office of Nuclear Energy. The approach in this paper identifies the features needed to cover the range of promising fuel cycle options identified in the DOE-NE Fuel Cycle Evaluation and Screening (E&S) and categorizes these features to facilitate prioritization. Features were categorized as essential functions, integrating features, and exemplary capabilities. One objective of this paper is to propose a library of unit tests applicable to each of the essential functions. Another underlying motivation for this paper is to encourage an international dialog on the functionalities and standard test methods for fuel cycle simulator tools.« less

Identification of speech transients using variable frame rate analysis and wavelet packets.

PubMed

Rasetshwane, Daniel M; Boston, J Robert; Li, Ching-Chung

2006-01-01

Speech transients are important cues for identifying and discriminating speech sounds. Yoo et al. and Tantibundhit et al. were successful in identifying speech transients and, emphasizing them, improving the intelligibility of speech in noise. However, their methods are computationally intensive and unsuitable for real-time applications. This paper presents a method to identify and emphasize speech transients that combines subband decomposition by the wavelet packet transform with variable frame rate (VFR) analysis and unvoiced consonant detection. The VFR analysis is applied to each wavelet packet to define a transitivity function that describes the extent to which the wavelet coefficients of that packet are changing. Unvoiced consonant detection is used to identify unvoiced consonant intervals and the transitivity function is amplified during these intervals. The wavelet coefficients are multiplied by the transitivity function for that packet, amplifying the coefficients localized at times when they are changing and attenuating coefficients at times when they are steady. Inverse transform of the modified wavelet packet coefficients produces a signal corresponding to speech transients similar to the transients identified by Yoo et al. and Tantibundhit et al. A preliminary implementation of the algorithm runs more efficiently.

Transient Cognitive Dynamics, Metastability, and Decision Making

PubMed Central

Rabinovich, Mikhail I.; Huerta, Ramón; Varona, Pablo; Afraimovich, Valentin S.

2008-01-01

The idea that cognitive activity can be understood using nonlinear dynamics has been intensively discussed at length for the last 15 years. One of the popular points of view is that metastable states play a key role in the execution of cognitive functions. Experimental and modeling studies suggest that most of these functions are the result of transient activity of large-scale brain networks in the presence of noise. Such transients may consist of a sequential switching between different metastable cognitive states. The main problem faced when using dynamical theory to describe transient cognitive processes is the fundamental contradiction between reproducibility and flexibility of transient behavior. In this paper, we propose a theoretical description of transient cognitive dynamics based on the interaction of functionally dependent metastable cognitive states. The mathematical image of such transient activity is a stable heteroclinic channel, i.e., a set of trajectories in the vicinity of a heteroclinic skeleton that consists of saddles and unstable separatrices that connect their surroundings. We suggest a basic mathematical model, a strongly dissipative dynamical system, and formulate the conditions for the robustness and reproducibility of cognitive transients that satisfy the competing requirements for stability and flexibility. Based on this approach, we describe here an effective solution for the problem of sequential decision making, represented as a fixed time game: a player takes sequential actions in a changing noisy environment so as to maximize a cumulative reward. As we predict and verify in computer simulations, noise plays an important role in optimizing the gain. PMID:18452000

Amelioration of cognitive impairment and changes in microtubule-associated protein 2 after transient global cerebral ischemia are influenced by complex environment experience.

PubMed

Briones, Teresita L; Woods, Julie; Wadowska, Magdalena; Rogozinska, Magdalena

2006-04-03

In this study we examined whether expression of microtubule-associated protein 2 (MAP2) after transient global cerebral ischemia can be influenced by behavioral experience and if the changes are associated with functional improvement. Rats received either ischemia or sham surgery then assigned to: complex environment housing (EC) or social housing (SC) as controls for 14 days followed by water maze testing. Upregulation of MAP2 was seen in all ischemic animals with a significant overall increase evident in the EC housed rats. Behaviorally, all animals learned to perform the water maze task over time but the ischemia SC rats had the worst performance overall while all the EC housed animals demonstrated the best performance in general. Regression analysis showed that increase MAP2 expression was able to explain some of the variance in the behavioral parameters in the water maze suggesting that this cytoskeletal protein probably played a role in mediating enhanced functional outcomes.

On the probability of violations of Fourier's law for heat flow in small systems observed for short times

NASA Astrophysics Data System (ADS)

Evans, Denis J.; Searles, Debra J.; Williams, Stephen R.

2010-01-01

We study the statistical mechanics of thermal conduction in a classical many-body system that is in contact with two thermal reservoirs maintained at different temperatures. The ratio of the probabilities, that when observed for a finite time, the time averaged heat flux flows in and against the direction required by Fourier's Law for heat flow, is derived from first principles. This result is obtained using the transient fluctuation theorem. We show that the argument of that theorem, namely, the dissipation function is, close to equilibrium, equal to a microscopic expression for the entropy production. We also prove that if transient time correlation functions of smooth zero mean variables decay to zero at long times, the system will relax to a unique nonequilibrium steady state, and for this state, the thermal conductivity must be positive. Our expressions are tested using nonequilibrium molecular dynamics simulations of heat flow between thermostated walls.

Pre-test analysis of protected loss of primary pump transients in CIRCE-HERO facility

NASA Astrophysics Data System (ADS)

Narcisi, V.; Giannetti, F.; Del Nevo, A.; Tarantino, M.; Caruso, G.

2017-11-01

In the frame of LEADER project (Lead-cooled European Advanced Demonstration Reactor), a new configuration of the steam generator for ALFRED (Advanced Lead Fast Reactor European Demonstrator) was proposed. The new concept is a super-heated steam generator, double wall bayonet tube type with leakage monitoring [1]. In order to support the new steam generator concept, in the framework of Horizon 2020 SESAME project (thermal hydraulics Simulations and Experiments for the Safety Assessment of MEtal cooled reactors), the ENEA CIRCE pool facility will be refurbished to host the HERO (Heavy liquid mEtal pRessurized water cOoled tubes) test section to investigate a bundle of seven full scale bayonet tubes in ALFRED-like thermal hydraulics conditions. The aim of this work is to verify thermo-fluid dynamic performance of HERO during the transition from nominal to natural circulation condition. The simulations have been performed with RELAP5-3D© by using the validated geometrical model of the previous CIRCE-ICE test section [2], in which the preceding heat exchanger has been replaced by the new bayonet bundle model. Several calculations have been carried out to identify thermal hydraulics performance in different steady state conditions. The previous calculations represent the starting points of transient tests aimed at investigating the operation in natural circulation. The transient tests consist of the protected loss of primary pump, obtained by reducing feed-water mass flow to simulate the activation of DHR (Decay Heat Removal) system, and of the loss of DHR function in hot conditions, where feed-water mass flow rate is absent. According to simulations, in nominal conditions, HERO bayonet bundle offers excellent thermal hydraulic behavior and, moreover, it allows the operation in natural circulation.

Analysis of Complex Valve and Feed Systems

NASA Technical Reports Server (NTRS)

Ahuja, Vineet; Hosangadi, Ashvin; Shipman, Jeremy; Cavallo, Peter; Dash, Sanford

2007-01-01

A numerical framework for analysis of complex valve systems supports testing of propulsive systems by simulating key valve and control system components in the test loop. In particular, it is designed to enhance the analysis capability in terms of identifying system transients and quantifying the valve response to these transients. This system has analysis capability for simulating valve motion in complex systems operating in diverse flow regimes ranging from compressible gases to cryogenic liquids. A key feature is the hybrid, unstructured framework with sub-models for grid movement and phase change including cryogenic cavitations. The multi-element unstructured framework offers improved predictions of valve performance characteristics under steady conditions for structurally complex valves such as pressure regulator valve. Unsteady simulations of valve motion using this computational approach have been carried out for various valves in operation at Stennis Space Center such as the split-body valve and the 10-in. (approx.25.4-cm) LOX (liquid oxygen) valve and the 4-in. (approx.10 cm) Y-pattern valve (liquid nitrogen). Such simulations make use of variable grid topologies, thereby permitting solution accuracy and resolving important flow physics in the seat region of the moving valve. An advantage to this software includes possible reduction in testing costs incurred due to disruptions relating to unexpected flow transients or functioning of valve/flow control systems. Prediction of the flow anomalies leading to system vibrations, flow resonance, and valve stall can help in valve scheduling and significantly reduce the need for activation tests. This framework has been evaluated for its ability to predict performance metrics like flow coefficient for cavitating venturis and valve coefficient curves, and could be a valuable tool in predicting and understanding anomalous behavior of system components at rocket propulsion testing and design sites.

Transient Seepage for Levee Engineering Analyses

NASA Astrophysics Data System (ADS)

Tracy, F. T.

2017-12-01

Historically, steady-state seepage analyses have been a key tool for designing levees by practicing engineers. However, with the advances in computer modeling, transient seepage analysis has become a potentially viable tool. A complication is that the levees usually have partially saturated flow, and this is significantly more complicated in transient flow. This poster illustrates four elements of our research in partially saturated flow relating to the use of transient seepage for levee design: (1) a comparison of results from SEEP2D, SEEP/W, and SLIDE for a generic levee cross section common to the southeastern United States; (2) the results of a sensitivity study of varying saturated hydraulic conductivity, the volumetric water content function (as represented by van Genuchten), and volumetric compressibility; (3) a comparison of when soils do and do not exhibit hysteresis, and (4) a description of proper and improper use of transient seepage in levee design. The variables considered for the sensitivity and hysteresis studies are pore pressure beneath the confining layer at the toe, the flow rate through the levee system, and a levee saturation coefficient varying between 0 and 1. Getting results for SEEP2D, SEEP/W, and SLIDE to match proved more difficult than expected. After some effort, the results matched reasonably well. Differences in results were caused by various factors, including bugs, different finite element meshes, different numerical formulations of the system of nonlinear equations to be solved, and differences in convergence criteria. Varying volumetric compressibility affected the above test variables the most. The levee saturation coefficient was most affected by the use of hysteresis. The improper use of pore pressures from a transient finite element seepage solution imported into a slope stability computation was found to be the most grievous mistake in using transient seepage in the design of levees.

Effect of the anti-androgenic endocrine disruptor vinclozolin on embryonic testis cord formation and postnatal testis development and function.

PubMed

Uzumcu, Mehmet; Suzuki, Hiroetsu; Skinner, Michael K

2004-01-01

Vinclozolin is a systemic dicarboximide fungicide that is used on fruits, vegetables, ornamental plants, and turf grass. Vinclozolin and its metabolites are known to be endocrine disruptors and act as androgen receptor antagonists. The hypothesis tested in the current study is that transient embryonic exposure to an anti-androgenic endocrine disruptor at the time of testis determination alters testis development and subsequently influences adult spermatogenic capacity and male reproduction. The effects of vinclozolin on embryonic testicular cord formation in vitro were examined, as well as the effects of transient in utero vinclozolin exposure on postnatal testis development and function. Embryonic day 13 (E13, sperm-positive vaginal smear day = E0) gonads were cultured in the absence or presence of vinclozolin (50-500microM). Vinclozolin treated gonads had significantly fewer cords (P < 0.05) and the histology of the cords that formed were abnormal as compared to vehicle-treated organs. Pregnant rats were exposed to vinclozolin (100 mg/kg/day) between embryonic days 8 and 14 (E8-E14) of development. Testis morphology and function were analyzed from postnatal day (P) 0, pubertal P20, and adult P60. No significant effect of vinclozolin on testis histology or germ cell viability was observed in P0 testis. The pubertal P20 testis from vinclozolin exposed animals had significantly higher numbers of apoptotic germ cells (P < 0.01), but testis weight was not affected. The adult P60 sperm motility was significantly lower in vinclozolin exposed males (P < 0.01). In addition, apoptotic germ cell number in testis of vinclozolin exposed animals was higher in adult P60 animals. Observations demonstrate that vinclozolin can effect embryonic testicular cord formation in vitro and that transient in utero exposure to vinclozolin increases apoptotic germ cell numbers in the testis of pubertal and adult animals. This correlated to reduced sperm motility in the adult. In conclusion, transient exposure to vinclozolin during the time of testis differentiation (i.e. cord formation) alters testis development and function. Observations indicate that transient exposure to an anti-androgenic endocrine disruptor during embryonic development causes delayed effects later in adult life on spermatogenic capacity.

Optogenetic mimicry of the transient activation of dopamine neurons by natural reward is sufficient for operant reinforcement.

PubMed

Kim, Kyung Man; Baratta, Michael V; Yang, Aimei; Lee, Doheon; Boyden, Edward S; Fiorillo, Christopher D

2012-01-01

Activation of dopamine receptors in forebrain regions, for minutes or longer, is known to be sufficient for positive reinforcement of stimuli and actions. However, the firing rate of dopamine neurons is increased for only about 200 milliseconds following natural reward events that are better than expected, a response which has been described as a "reward prediction error" (RPE). Although RPE drives reinforcement learning (RL) in computational models, it has not been possible to directly test whether the transient dopamine signal actually drives RL. Here we have performed optical stimulation of genetically targeted ventral tegmental area (VTA) dopamine neurons expressing Channelrhodopsin-2 (ChR2) in mice. We mimicked the transient activation of dopamine neurons that occurs in response to natural reward by applying a light pulse of 200 ms in VTA. When a single light pulse followed each self-initiated nose poke, it was sufficient in itself to cause operant reinforcement. Furthermore, when optical stimulation was delivered in separate sessions according to a predetermined pattern, it increased locomotion and contralateral rotations, behaviors that are known to result from activation of dopamine neurons. All three of the optically induced operant and locomotor behaviors were tightly correlated with the number of VTA dopamine neurons that expressed ChR2, providing additional evidence that the behavioral responses were caused by activation of dopamine neurons. These results provide strong evidence that the transient activation of dopamine neurons provides a functional reward signal that drives learning, in support of RL theories of dopamine function.

Transient Heat Transfer in TCAP Coils

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

Steimke, J.L.

1999-03-09

The Thermal Cycling Absorption Process (TCAP) is used to separate isotopes of hydrogen. TCAP involves passing a stream of mixed hydrogen isotopes through palladium deposited on kieselguhr (Pd/k) while cycling the temperature of the Pd/k. Kieselguhr is a silica mineral also called diatomite. To aid in the design of a full scale facility, the Thermal Fluids Laboratory was used by the Chemical and Hydrogen Technology Section to compare the heat transfer properties of three different configurations of stainless steel coils containing kieselguhr and helium. Testing of coils containing Pd/k and hydrogen isotopes would have been more prototypical but would havemore » been too expensive. Three stainless steel coils filled with kieselguhr were tested; one made from 2.0 inch diameter tubing, one made from 2.0 inch diameter tubing with foam copper embedded in the kieselguhr and one made from 1.25 inch diameter tubing. It was known prior to testing that increasing the tubing diameter from 1.25 inch to 2.0 inch would slow the rate of temperature change. The primary purpose of the testing was to measure to what extent the presence of copper foam in a 2.0" tubing coil would compensate for the effect of larger diameter. Each coil was connected to a pressure gage and the coil was evacuated and backfilled with helium gas. Helium was used instead of a mixture of hydrogen isotopes for reasons of safety. Each coil was quickly immersed in a stirred bath of ethylene glycol at a temperature of approximately 100 degrees Celsius. The coil pressure increased, reflecting the increase in average temperature of its contents. The pressure transient was recored as a function of time after immersion. Because of the actual process will use Pd/k instead of kieselguhr, additional tests were run to determine the differences in thermal properties between the two materials. The method was to position a thermocouple at the center of a hollow sphere and pack the sphere with Pd/k. The sphere was sealed, quickly submerged in a bath of boiling water and the temperature transient was recorded. There sphere was then opened, the Pd/k was replaced with kieselguhr and the transient was repeated. The response was a factor of 1.4 faster for Pd/k than for kieselguhr, implying a thermal diffusivity approximately 40 percent higher than for kieselguhr. Another implication is that the transient tests with the coils would have proceeded faster if the coils had been filled with Pd/k rather than kieselguhr.« less

Transient Heat Transfer in TCAP Coils

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

Steimke, J.L.

1999-03-09

The Thermal Cycling Absorption Process (TCAP) is used to separate isotopes of hydrogen. TCAP involves passing a stream of mixed hydrogen isotopes through palladium deposited on kieselguhr (Pd/k) while cycling the temperature of the Pd/k. Kieselguhr is a silica mineral also called diatomite. To aid in the design of a full scale facility, the Thermal Fluids Laboratory was used by the Chemical and Hydrogen Technology Section to compare the heat transfer properties of three different configurations of stainless steel coils containing kieselguhr and helium. Testing of coils containing Pd/k and hydrogen isotopes would have been more prototypical but would havemore » been too expensive. Three stainless steel coils filled with kieselguhr were tested; one made from 2.0 inch diameter tubing, one made from 2.0 inch diameter tubing with foam copper embedded in the kieselguhr and one made from 1.25 inch diameter tubing. It was known prior to testing that increasing the tubing diameter from 1.25 inch to 2.0 inch would slow the rate of temperature change. The primary purpose of the testing was to measure to what extent the presence of copper foam in a 2.0 tubing coil would compensate for the effect of larger diameter. Each coil was connected to a pressure gage and the coil was evacuated and backfilled with helium gas. Helium was used instead of a mixture of hydrogen isotopes for reasons of safety. Each coil was quickly immersed in a stirred bath of ethylene glycol at a temperature of approximately 100 degrees Celsius. The coil pressure increased, reflecting the increase in average temperature of its contents. The pressure transient was recored as a function of time after immersion. Because of the actual process will use Pd/k instead of kieselguhr, additional tests were run to determine the differences in thermal properties between the two materials. The method was to position a thermocouple at the center of a hollow sphere and pack the sphere with Pd/k. The sphere was sealed, quickly submerged in a bath of boiling water and the temperature transient was recorded. There sphere was then opened, the Pd/k was replaced with kieselguhr and the transient was repeated. The response was a factor of 1.4 faster for Pd/k than for kieselguhr, implying a thermal diffusivity approximately 40 percent higher than for kieselguhr. Another implication is that the transient tests with the coils would have proceeded faster if the coils had been filled with Pd/k rather than kieselguhr.« less

Sustained and transient attention in the continuous performance task.

PubMed

Smid, H G O M; de Witte, M R; Homminga, I; van den Bosch, R J

2006-08-01

One of the most frequently applied methods to study abnormal cognition is the Continuous Performance Task (CPT). It is unclear, however, which cognitive functions are engaged in normal CPT performance. The aims of the present study were to identify the neurocognitive functions engaged in the main variants of the CPT and to determine to what extent these variants differentially engage these functions. We hypothesized that the main CPT versions (CPT-X, CPT-AX, CPT-Identical Pairs) can be distinguished by whether they demand sustained or transient attention and sustained or transient response preparation. Transient attention to objects like letters or digits, that is, the need to switch attention to different objects from trial to trial, impairs target detection accuracy relative to sustained attention to a single object. Transient response preparation, that is, the possibility to switch response preparation on and off from trial to trial, improves response speed relative to having to sustain response preparation across all trials. Comparison of task performance and Event-Related brain Potentials (ERPs) of healthy participants obtained in the main CPT variants confirmed these hypotheses. Behavioral and ERP measures indicated worse target detection in the CPT-AX than in the CPT-X, consistent with a higher demand on transient attention in that task. In contrast, behavioral and ERP measures indicated higher response speed in the CPT-AX than in the CPT-X, associated with more response preparation in advance of the targets. This supports the idea of increased transient response preparation in the CPT-AX. We conclude that CPTs differ along at least two task variables that each influences a different cognitive function.

Transient dynamics of a flexible rotor with squeeze film dampers

NASA Technical Reports Server (NTRS)

Buono, D. F.; Schlitzer, L. D.; Hall, R. G., III; Hibner, D. H.

1978-01-01

A series of simulated blade loss tests are reported on a test rotor designed to operate above its second bending critical speed. A series of analyses were performed which predicted the transient behavior of the test rig for each of the blade loss tests. The scope of the program included the investigation of transient rotor dynamics of a flexible rotor system, similar to modern flexible jet engine rotors, both with and without squeeze film dampers. The results substantiate the effectiveness of squeeze film dampers and document the ability of available analytical methods to predict their effectiveness and behavior.

Bridging Grafts and Transient Nerve Growth Factor Infusions Promote Long-Term Central Nervous System Neuronal Rescue and Partial Functional Recovery

NASA Astrophysics Data System (ADS)

Tuszynski, Mark H.; Gage, Fred H.

1995-05-01

Grafts of favorable axonal growth substrates were combined with transient nerve growth factor (NGF) infusions to promote morphological and functional recovery in the adult rat brain after lesions of the septohippocampal projection. Long-term septal cholinergic neuronal rescue and partial hippocampal reinnervation were achieved, resulting in partial functional recovery on a simple task assessing habituation but not on a more complex task assessing spatial reference memory. Control animals that received transient NGF infusions without axonal-growth-promoting grafts lacked behavioral recovery but also showed long-term septal neuronal rescue. These findings indicate that (i) partial recovery from central nervous system injury can be induced by both preventing host neuronal loss and promoting host axonal regrowth and (ii) long-term neuronal loss can be prevented with transient NGF infusions.

Comparison of Single-Event Transients Induced in an Operational Amplifier (LM124) by Pulsed Laser Light and a Broad Beam of Heavy Ions

NASA Technical Reports Server (NTRS)

Buchner, Steve; McMorrow, Dale; Poivey, Christian; Howard, James, Jr.; Pease, Rom; Savage, Mark; Boulghassoul, Younis; Massengill, Lloyd

2003-01-01

A comparison of transients from heavy-ion and pulsed-laser testing shows good agreement for many different voltage configurations. The agreement is illustrated by comparing directly individual transients and plots of transient amplitude versus width.

Therapeutic effects of oral dimethyl fumarate on stroke induced by middle cerebral artery occlusion: An animal experimental study.

PubMed

Safari, Anahid; Fazeli, Mehdi; Namavar, Mohammad Reza; Tanideh, Nader; Jafari, Peyman; Borhani-Haghighi, Afshin

2017-01-01

Dimethyl fumarate (DMF) has immune-modulatory and neuro-protective characteristics that can be used for treatment of acute ischemic stroke. To investigate the therapeutic effects of DMF on histological and functional recovery of rats after transient middle cerebral artery (MCA) occlusion. 22 Sprague-Dawley male rats weighing 275-300 g were randomized into three groups by block randomization. In the sham group (n = 7), the neck was opened, but neither MCA was occluded, nor any drug was administered.The control group (n = 7) was treated with vehicle (methocel) by gavage for 14 days after MCA occlusion. In the DMF-treated group (n = 8), treatment was performed with 15 mg/kg body weight dimethyl fumarate twice a day for 14 days after MCA occlusion. Transient occlusion of the right MCA was performed by intraluminal thread method in the DMF-treated and the control group. Neurological deficit score (NDS), pole test, and adhesive removal test were performed before the surgery, and on post-operative Days 0, 3, 5, 7, 10, and 14. After the final behaviour test, the animals' brains were perfused and removed. Brains were frozen and sectioned serially and coronally using a cryostat. Infract volume and brain volume were estimated by stereology. The percentage of infarct volume was significantly lower in DMF-treated animals (5.76%) than in the control group (22.39%) (P < 0.0001). Regarding behavioural tests, the DMF-treated group showed better function in NDS on Days 7 (P = 0.041) and 10 (P = 0.046), but not in pole and adhesive removal tests. There was no significant correlation between behavioural tests and histological results. Dimethyl fumarate could be beneficial as a potential neuroprotective agent in the treatment of stroke.

Experimental research made during a city cycle on the feasibility of electrically charged SI engines

NASA Astrophysics Data System (ADS)

Kocsis, Levente B.; Burnete, Nicolae

2014-06-01

The paper presents experimental research on performance improvements in a city cycle (operating mostly transient) of a compact class vehicle equipped with a turbocharged SI engine which had attached an electric charger, to improve engine response at low operational speeds. During tests, functional parameters, energy consumption of the electric charger and vehicle performances were measured while driving in two operating conditions: with active and inactive electric charger. The tests were carried out on a well-defined path, in the same driving style, by the same driver.

Real-time Recovery Efficiencies and Performance of the Palomar Transient Factory’s Transient Discovery Pipeline

NASA Astrophysics Data System (ADS)

Frohmaier, C.; Sullivan, M.; Nugent, P. E.; Goldstein, D. A.; DeRose, J.

2017-05-01

We present the transient source detection efficiencies of the Palomar Transient Factory (PTF), parameterizing the number of transients that PTF found versus the number of similar transients that occurred over the same period in the survey search area but were missed. PTF was an optical sky survey carried out with the Palomar 48 inch telescope over 2009-2012, observing more than 8000 square degrees of sky with cadences of between one and five days, locating around 50,000 non-moving transient sources, and spectroscopically confirming around 1900 supernovae. We assess the effectiveness with which PTF detected transient sources, by inserting ≃ 7 million artificial point sources into real PTF data. We then study the efficiency with which the PTF real-time pipeline recovered these sources as a function of the source magnitude, host galaxy surface brightness, and various observing conditions (using proxies for seeing, sky brightness, and transparency). The product of this study is a multi-dimensional recovery efficiency grid appropriate for the range of observing conditions that PTF experienced and that can then be used for studies of the rates, environments, and luminosity functions of different transient types using detailed Monte Carlo simulations. We illustrate the technique using the observationally well-understood class of type Ia supernovae.

Assessment of Lightning Transients on a De-Iced Rotor Blade with Predictive Tools and Coaxial Return Measurements

NASA Astrophysics Data System (ADS)

Guillet, S.; Gosmain, A.; Ducoux, W.; Ponçon, M.; Fontaine, G.; Desseix, P.; Perraud, P.

2012-05-01

The increasing use of composite materials in aircrafts primary structures has led to different problematics in the field of safety of flight in lightning conditions. The consequences of this technological mutation, which occurs in a parallel context of extension of electrified critical functions, are addressed by aircraft manufacturers through the enhancement of their available assessment means of lightning transient. On the one hand, simulation tools, provided an accurate description of aircraft design, are today valuable assessment tools, in both predictive and operative terms. On the other hand, in-house test means allow confirmation and consolidation of design office hardening solutions. The combined use of predictive simulation tools and in- house test means offers an efficient and reliable support for all aircraft developments in their various life-time stages. The present paper provides PREFACE research project results that illustrate the above introduced strategy on the de-icing system of the NH90 composite main rotor blade.

High-resolution heat-transfer-coefficient maps applicable to compound-curve surfaces using liquid crystals in a transient wind tunnel

NASA Technical Reports Server (NTRS)

Jones, Terry V.; Hippensteele, Steven A.

1988-01-01

Tests were performed in a transient heat transfer tunnel in which the model under test was preheated prior to allowing room temperature air to be suddenly drawn over the model. The resulting movement of isothermal contours on the model is revealed using a surface coating of thermochromic liquid crystals that display distinctive colors at particular temperatures. A video record is obtained of a temperature and time data pair for all points on the model during a single test. Experiments on a duct model are reported in which the model was preheated using a hot air stream. A manner in which initial model temperature nonuniformities could be taken into account was investigated. The duct model was also tested with a steady-state measurement technique and results were compared with the transient measurements, but recognizing that differences existed between the upstream thermal boundary conditions. The steady-state and transient measurements were shown to be consistent with predicted values. The main advantage of this transient heat transfer technique using liquid crystals is that since the test model need not be actively heated, high-resolution measurements on surfaces with complex shapes may be obtained.

Alternatives Analysis for the Resumption of Transient Testing Program

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

Lee Nelson

2013-11-01

An alternatives analysis was performed for resumption of transient testing. The analysis considered eleven alternatives – including both US international facilities. A screening process was used to identify two viable alternatives from the original eleven. In addition, the alternatives analysis includes a no action alternative as required by the National Environmental Policy Act (NEPA). The alternatives considered in this analysis included: 1. Restart the Transient Reactor Test Facility (TREAT) 2. Modify the Annular Core Research Reactor (ACRR) which includes construction of a new hot cell and installation of a new hodoscope. 3. No Action

Transient and Steady-state Tests of the Space Power Research Engine with Resistive and Motor Loads

NASA Technical Reports Server (NTRS)

Rauch, Jeffrey S.; Kankam, M. David

1995-01-01

The NASA Lewis Research Center (LeRC) has been testing free-piston Stirling engine/linear alternators (FPSE/LA) to develop advanced power convertors for space-based electrical power generation. Tests reported herein were performed to evaluate the interaction and transient behavior of FPSE/LA-based power systems with typical user loads. Both resistive and small induction motor loads were tested with the space power research engine (SPRE) power system. Tests showed that the control system could maintain constant long term voltage and stable periodic operation over a large range of engine operating parameters and loads. Modest resistive load changes were shown to cause relatively large voltage and, therefore, piston and displacer amplitude excursions. Starting a typical small induction motor was shown to cause large and, in some cases, deleterious voltage transients. The tests identified the need for more effective controls, if FPSE/LAs are to be used for stand-alone power systems. The tests also generated a large body of transient dynamic data useful for analysis code validation.

Transient and steady-state tests of the space power research engine with resistive and motor loads

NASA Astrophysics Data System (ADS)

Rauch, Jeffrey S.; Kankam, M. David

1995-01-01

The NASA Lewis Research Center (LeRC) has been testing free-piston Stirling engine/linear alternators (FPSE/LA) to develop advanced power convertors for space-based electrical power generation. Tests reported herein were performed to evaluate the interaction and transient behavior of FPSE/LA-based power systems with typical user loads. Both resistive and small induction motor loads were tested with the space power research engine (SPRE) power system. Tests showed that the control system could maintain constant long term voltage and stable periodic operation over a large range of engine operating parameters and loads. Modest resistive load changes were shown to cause relatively large voltage and, therefore, piston and displacer amplitude excursions. Starting a typical small induction motor was shown to cause large and, in some cases, deleterious voltage transients. The tests identified the need for more effective controls, if FPSE/LAs are to be used for stand-alone power systems. The tests also generated a large body of transient dynamic data useful for analysis code validation.

Aspirating Seal Development: Analytical Modeling and Seal Test Rig

NASA Technical Reports Server (NTRS)

Bagepalli, Bharat

1996-01-01

This effort is to develop large diameter (22 - 36 inch) Aspirating Seals for application in aircraft engines. Stein Seal Co. will be fabricating the 36-inch seal(s) for testing. GE's task is to establish a thorough understanding of the operation of Aspirating Seals through analytical modeling and full-scale testing. The two primary objectives of this project are to develop the analytical models of the aspirating seal system, to upgrade using GE's funds, GE's 50-inch seal test rig for testing the Aspirating Seal (back-to-back with a corresponding brush seal), test the aspirating seal(s) for seal closure, tracking and maneuver transients (tilt) at operating pressures and temperatures, and validate the analytical model. The objective of the analytical model development is to evaluate the transient and steady-state dynamic performance characteristics of the seal designed by Stein. The transient dynamic model uses a multi-body system approach: the Stator, Seal face and the rotor are treated as individual bodies with relative degrees of freedom. Initially, the thirty-six springs are represented as a single one trying to keep open the aspirating face. Stops (Contact elements) are provided between the stator and the seal (to compensate the preload in the fully-open position) and between the rotor face and Seal face (to detect rub). The secondary seal is considered as part of the stator. The film's load, damping and stiffness characteristics as functions of pressure and clearance are evaluated using a separate (NASA) code GFACE. Initially, a laminar flow theory is used. Special two-dimensional interpolation routines are written to establish exact film load and damping values at each integration time step. Additionally, other user-routines are written to read-in actual pressure, rpm, stator-growth and rotor growth data and, later, to transfer these as appropriate loads/motions in the system-dynamic model. The transient dynamic model evaluates the various motions, clearances and forces as the seals are subjected to different aircraft maneuvers: Windmilling restart; start-ground idle; ground idle-takeoff; takeoff-burst chop, etc. Results of this model show that the seal closes appropriately and does not ram into the rotor for all of the conditions analyzed. The rig upgrade design for testing Aspirating Seals has been completed. Long lead-time items (forgings, etc.) have been ordered.

Transient Testing of Nuclear Fuels and Materials in the United States

NASA Astrophysics Data System (ADS)

Wachs, Daniel M.

2012-12-01

The United States has established that transient irradiation testing is needed to support advanced light water reactors fuel development. The U.S. Department of Energy (DOE) has initiated an effort to reestablish this capability. Restart of the Transient Testing Reactor (TREAT) facility located at the Idaho National Laboratory (INL) is being considered for this purpose. This effort would also include the development of specialized test vehicles to support stagnant capsule and flowing loop tests as well as the enhancement of postirradiation examination capabilities and remote device assembly capabilities at the Hot Fuel Examination Facility. It is anticipated that the capability will be available to support testing by 2018, as required to meet the DOE goals for the development of accident-tolerant LWR fuel designs.

Effect of truck operating weight on heavy-duty diesel emissions.

PubMed

Gajendran, Prakash; Clark, Nigel N

2003-09-15

Heavy-duty diesel vehicles are substantial contributors of oxides of nitrogen (NO(x)) and particulate matter (PM) while carbon monoxide and hydrocarbon (HC) emissions from diesel vehicles receive less attention. Truck emissions inventories have traditionally employed average fuel economy and engine efficiency factors to translate certification into distance-specific (g/mi) data, so that inventories do not take into account the real effects of truck operating weight on emissions. The objective of this research was to examine weight corrections for class 7 and 8 vehicles (over 26 000 lb (11 793 kg) gross vehicle weight) from a theoretical point of view and to present a collection of original data on the topic. It was found by combining an empirical equation with theoretical truck loads that the NO(x) emissions increased by approximately 54% for a doubling of test weight. Emissions data were gathered from specific tests performed using different test weights and using various test schedules, which can consist of cycles or routes. It was found experimentally that NO(x) emissions have a nearly linear correlation with vehicle weight and did not vary much from vehicle to vehicle. NO(x) emissions were also found to be insensitive to transient operation in the test schedule. The observed trends correlate well with the theory presented, and hence, the NO(x) emissions can be predicted reasonably accurately using the theory. If NO(x) data were considered in fuel-specific (g/gal) units, they did not vary with the test weight. HC emissions were found to be insensitive to the vehicle weight. CO and PM emissions were found to be a strong function of weight during transient operation. Under transient operation, the CO emissions value increased by 36% for an increase in test weight from 42 000 (19 051 kg) to 56 000 lb (25 401 kg). However, CO and PM were found to be insensitive to the vehicle weight during nearly steady-state operation.

On the numerical solution of the dynamically loaded hydrodynamic lubrication of the point contact problem

NASA Technical Reports Server (NTRS)

Lim, Sang G.; Brewe, David E.; Prahl, Joseph M.

1990-01-01

The transient analysis of hydrodynamic lubrication of a point-contact is presented. A body-fitted coordinate system is introduced to transform the physical domain to a rectangular computational domain, enabling the use of the Newton-Raphson method for determining pressures and locating the cavitation boundary, where the Reynolds boundary condition is specified. In order to obtain the transient solution, an explicit Euler method is used to effect a time march. The transient dynamic load is a sinusoidal function of time with frequency, fractional loading, and mean load as parameters. Results include the variation of the minimum film thickness and phase-lag with time as functions of excitation frequency. The results are compared with the analytic solution to the transient step bearing problem with the same dynamic loading function. The similarities of the results suggest an approximate model of the point contact minimum film thickness solution.

Orbiter integrated active thermal control subsystem test

NASA Technical Reports Server (NTRS)

Jaax, J. R.

1980-01-01

Integrated subsystem level testing of the systems within the orbiter active thermal chamber capable of simulating ground, orbital, and entry temperature and pressure profiles. The test article was in a closed loop configuration that included flight type and functionally simulated protions of all ATCS components for collecting, transporting, and rejecting orbiter waste heat. Specially designed independently operating equipment simulated the transient thermal input from the cabin, payload, fuel cells, freon cold plates, hydraulic system, and space environment. Test team members using data, controls, and procedures available to a flight crew controlled the operation of the ATCS. The ATCS performance met or exceeded all thermal and operational requirements for planned and contingency mission support.

Dynamic Modeling and Testing of MSRR-1 for Use in Microgravity Environments Analysis

NASA Technical Reports Server (NTRS)

Gattis, Christy; LaVerde, Bruce; Howell, Mike; Phelps, Lisa H. (Technical Monitor)

2001-01-01

Delicate microgravity science is unlikely to succeed on the International Space Station if vibratory and transient disturbers corrupt the environment. An analytical approach to compute the on-orbit acceleration environment at science experiment locations within a standard payload rack resulting from these disturbers is presented. This approach has been grounded by correlation and comparison to test verified transfer functions. The method combines the results of finite element and statistical energy analysis using tested damping and modal characteristics to provide a reasonable approximation of the total root-mean-square (RMS) acceleration spectra at the interface to microgravity science experiment hardware.

Predicting permanent and transient protein-protein interfaces.

PubMed

La, David; Kong, Misun; Hoffman, William; Choi, Youn Im; Kihara, Daisuke

2013-05-01

Protein-protein interactions (PPIs) are involved in diverse functions in a cell. To optimize functional roles of interactions, proteins interact with a spectrum of binding affinities. Interactions are conventionally classified into permanent and transient, where the former denotes tight binding between proteins that result in strong complexes, whereas the latter compose of relatively weak interactions that can dissociate after binding to regulate functional activity at specific time point. Knowing the type of interactions has significant implications for understanding the nature and function of PPIs. In this study, we constructed amino acid substitution models that capture mutation patterns at permanent and transient type of protein interfaces, which were found to be different with statistical significance. Using the substitution models, we developed a novel computational method that predicts permanent and transient protein binding interfaces (PBIs) in protein surfaces. Without knowledge of the interacting partner, the method uses a single query protein structure and a multiple sequence alignment of the sequence family. Using a large dataset of permanent and transient proteins, we show that our method, BindML+, performs very well in protein interface classification. A very high area under the curve (AUC) value of 0.957 was observed when predicted protein binding sites were classified. Remarkably, near prefect accuracy was achieved with an AUC of 0.991 when actual binding sites were classified. The developed method will be also useful for protein design of permanent and transient PBIs. Copyright © 2013 Wiley Periodicals, Inc.

Femtosecond tracking of carrier relaxation in germanium with extreme ultraviolet transient reflectivity

NASA Astrophysics Data System (ADS)

Kaplan, Christopher J.; Kraus, Peter M.; Ross, Andrew D.; Zürch, Michael; Cushing, Scott K.; Jager, Marieke F.; Chang, Hung-Tzu; Gullikson, Eric M.; Neumark, Daniel M.; Leone, Stephen R.

2018-05-01

Extreme ultraviolet (XUV) transient reflectivity around the germanium M4 ,5 edge (3 d core-level to valence transition) at 30 eV is advanced to obtain the transient dielectric function of crystalline germanium [100] on femtosecond to picosecond time scales following photoexcitation by broadband visible-to-infrared (VIS/NIR) pulses. By fitting the transient dielectric function, carrier-phonon induced relaxations are extracted for the excited carrier distribution. The measurements reveal a hot electron relaxation rate of 3.2 ±0.2 ps attributed to the X -L intervalley scattering and a hot hole relaxation rate of 600 ±300 fs ascribed to intravalley scattering within the heavy hole (HH) band, both in good agreement with previous work. An overall energy shift of the XUV dielectric function is assigned to a thermally induced band gap shrinkage by formation of acoustic phonons, which is observed to be on a timescale of 4-5 ps, in agreement with previously measured optical phonon lifetimes. The results reveal that the transient reflectivity signal at an angle of 66∘ with respect to the surface normal is dominated by changes to the real part of the dielectric function, due to the near critical angle of incidence of the experiment (66∘-70∘) for the range of XUV energies used. This work provides a methodology for interpreting XUV transient reflectivity near core-level transitions, and it demonstrates the power of the XUV spectral region for measuring ultrafast excitation dynamics in solids.

Posttest data analysis and assessment of TRAC-BD1/MOD1 with data from a Full Integral Simulation Test (FIST) power transient experiment

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

Wheatley, P.D.; Wagner, K.C.

The FIST power transient test 6PMC2 was analyzed to further the understanding of the FIST facility and provide an assessment of TRAC-BD1/MOD1. FIST power transient 6PMC2 investigated the thermal-hydraulic response following inadvertent closure of the main steam isolation valve and the subsequent failure of the reactor to scram. Failure of the high pressure core spray system was also assumed, resulting on only the reactor core isolation cooling flow for inventory makeup during the transient. The experiment was a sensitivity study with relatively high core power and low makeup rates. This study provides one of the first opportunities to assess TRAC-BD1/MOD1more » under power transient and natural circulation conditions with data from a facility with prototypical BWR geometry. The power transient test was analyzed with emphasis on the following phenomena; (a) the system pressure response, (b) the natural circulation flows and rates, and (c) the heater rod cladding temperature response. Based on the results of this study, TRAC-BD1/MOD1 can be expected to calculate the thermal-hydraulic behavior of a BWR during a power transient.« less

Wavelet-based system identification of short-term dynamic characteristics of arterial baroreflex.

PubMed

Kashihara, Koji; Kawada, Toru; Sugimachi, Masaru; Sunagawa, Kenji

2009-01-01

The assessment of arterial baroreflex function in cardiovascular diseases requires quantitative evaluation of dynamic and static baroreflex properties because of the frequent modulation of baroreflex properties with unstable hemodynamics. The purpose of this study was to identify the dynamic baroreflex properties from transient changes of step pressure inputs with background noise during a short-duration baroreflex test in anesthetized rabbits with isolated carotid sinuses, using a modified wavelet-based time-frequency analysis. The proposed analysis was able to identify the transfer function of baroreflex as well as static properties from the transient input-output responses under normal [gain at 0.04 Hz from carotid sinus pressure (CSP) to arterial pressure (n = 8); 0.29 +/- 0.05 at low (40-60 mmHg), 1.28 +/- 0.12 at middle (80-100 mmHg), and 0.38 +/- 0.07 at high (120-140 mmHg) CSP changes] and pathophysiological [gain in control vs. phenylbiguanide (n = 8); 0.32 +/- 0.07 vs. 0.39 +/- 0.09 at low, 1.39 +/- 0.15 vs. 0.59 +/- 0.09 (p < 0.01) at middle, and 0.35 +/- 0.04 vs. 0.15 +/- 0.02 (p < 0.01) at high CSP changes] conditions. Subsequently, we tested the proposed wavelet-based method under closed-loop baroreflex responses; the simulation study indicates that it may be applicable to clinical situations for accurate assessment of dynamic baroreflex function. In conclusion, the dynamic baroreflex property to various pressure inputs could be simultaneously extracted from the step responses with background noise.

Single Event Transient Analysis of an SOI Operational Amplifier for Use in Low-Temperature Martian Exploration

NASA Technical Reports Server (NTRS)

Laird, Jamie S.; Scheik, Leif; Vizkelethy, Gyorgy; Mojarradi, Mohammad M; Chen, Yuan; Miyahira, Tetsuo; Blalock, Benjamin; Greenwell, Robert; Doyle, Barney

2006-01-01

The next generation of Martian rover#s to be launched by JPL are to examine polar regions where temperatures are extremely low and the absence of an earth-like atmosphere results in high levels of cosmic radiation at ground level. Cosmic rays lead to a plethora of radiation effects including Single Event Transients (SET) which can severely degrade microelectronic functionality. As such, a radiation-hardened, temperature compensated CMOS Single-On-Insulator (SOI) Operational Amplifier has been designed for JPL by the University of Tennessee and fabricated by Honeywell using the SOI V process. SOI technology has been shownto be far less sensitive to transient effects than both bulk and epilayer Si. Broad beam heavy-ion tests at the University of Texas A&M using Kr and Xebeams of energy 25MeV/amu were performed to ascertain the duration and severity of the SET for the op-amp configured for a low and high gain application. However, some ambiguity regarding the location of transient formation required the use of a focused MeV ion microbeam. A 36MeV O6(+) microbeam. the Sandia National Laboratory (SNL) was used to image and verify regions of particular concern. This is a viewgraph presentation

Apparent transient effects of recent "ecstasy" use on cognitive performance and extrapyramidal signs in human subjects.

PubMed

Smith, Ryan M; Tivarus, Madalina; Campbell, Heather L; Hillier, Ashleigh; Beversdorf, David Q

2006-09-01

Our purpose is to investigate cognitive performance and extrapyramidal function early after ecstasy use. Ecstasy, containing 3,4 methylenedioxymethamphetamine, has shown evidence of causing cognitive deficits and parkinsonian signs. Previous research has examined cognitive performance after a period of prolonged abstinence, but research assessing the early effects of ecstasy after recent use is limited despite temporal neurochemical differences demonstrated in nonhuman models. This study compared task performance between 13 ecstasy users (10 to 15 h postdrug use) and a control group on a battery of neuropsychologic assessments while matching for education level, sleep deprivation, and premorbid IQ. The groups were also compared on measures relating to parkinsonian signs. The ecstasy subjects showed impairments on measures of executive function as evaluated by Raven's Standard Progressive Matrices (SPM) and the Wisconsin Card Sorting Task (WCST). Short-delay free recall memory was also impaired in ecstasy subjects on the California Verbal Learning Test (CVLT-II). No extrapyramidal motor impairments were detected. These deficits resemble deficits previously reported in chronic ecstasy use but also seem to reveal transient impairments in executive function. Future research is needed to better understand the neurologic and neuropsychologic implications of ecstasy use across time and extent of use.

Real-time Recovery Efficiencies and Performance of the Palomar Transient Factory's Transient Discovery Pipeline

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

Frohmaier, C.; Sullivan, M.; Nugent, P. E.

In this paper, we present the transient source detection efficiencies of the Palomar Transient Factory (PTF), parameterizing the number of transients that PTF found versus the number of similar transients that occurred over the same period in the survey search area but were missed. PTF was an optical sky survey carried out with the Palomar 48 inch telescope over 2009–2012, observing more than 8000 square degrees of sky with cadences of between one and five days, locating around 50,000 non-moving transient sources, and spectroscopically confirming around 1900 supernovae. We assess the effectiveness with which PTF detected transient sources, by insertingmore » $$\\simeq 7$$ million artificial point sources into real PTF data. We then study the efficiency with which the PTF real-time pipeline recovered these sources as a function of the source magnitude, host galaxy surface brightness, and various observing conditions (using proxies for seeing, sky brightness, and transparency). The product of this study is a multi-dimensional recovery efficiency grid appropriate for the range of observing conditions that PTF experienced and that can then be used for studies of the rates, environments, and luminosity functions of different transient types using detailed Monte Carlo simulations. Finally, we illustrate the technique using the observationally well-understood class of type Ia supernovae.« less

Real-time Recovery Efficiencies and Performance of the Palomar Transient Factory's Transient Discovery Pipeline

DOE PAGES

Frohmaier, C.; Sullivan, M.; Nugent, P. E.; ...

2017-05-09

In this paper, we present the transient source detection efficiencies of the Palomar Transient Factory (PTF), parameterizing the number of transients that PTF found versus the number of similar transients that occurred over the same period in the survey search area but were missed. PTF was an optical sky survey carried out with the Palomar 48 inch telescope over 2009–2012, observing more than 8000 square degrees of sky with cadences of between one and five days, locating around 50,000 non-moving transient sources, and spectroscopically confirming around 1900 supernovae. We assess the effectiveness with which PTF detected transient sources, by insertingmore » $$\\simeq 7$$ million artificial point sources into real PTF data. We then study the efficiency with which the PTF real-time pipeline recovered these sources as a function of the source magnitude, host galaxy surface brightness, and various observing conditions (using proxies for seeing, sky brightness, and transparency). The product of this study is a multi-dimensional recovery efficiency grid appropriate for the range of observing conditions that PTF experienced and that can then be used for studies of the rates, environments, and luminosity functions of different transient types using detailed Monte Carlo simulations. Finally, we illustrate the technique using the observationally well-understood class of type Ia supernovae.« less

Transient Reliability Analysis Capability Developed for CARES/Life

NASA Technical Reports Server (NTRS)

Nemeth, Noel N.

2001-01-01

The CARES/Life software developed at the NASA Glenn Research Center provides a general-purpose design tool that predicts the probability of the failure of a ceramic component as a function of its time in service. This award-winning software has been widely used by U.S. industry to establish the reliability and life of a brittle material (e.g., ceramic, intermetallic, and graphite) structures in a wide variety of 21st century applications.Present capabilities of the NASA CARES/Life code include probabilistic life prediction of ceramic components subjected to fast fracture, slow crack growth (stress corrosion), and cyclic fatigue failure modes. Currently, this code can compute the time-dependent reliability of ceramic structures subjected to simple time-dependent loading. For example, in slow crack growth failure conditions CARES/Life can handle sustained and linearly increasing time-dependent loads, whereas in cyclic fatigue applications various types of repetitive constant-amplitude loads can be accounted for. However, in real applications applied loads are rarely that simple but vary with time in more complex ways such as engine startup, shutdown, and dynamic and vibrational loads. In addition, when a given component is subjected to transient environmental and or thermal conditions, the material properties also vary with time. A methodology has now been developed to allow the CARES/Life computer code to perform reliability analysis of ceramic components undergoing transient thermal and mechanical loading. This means that CARES/Life will be able to analyze finite element models of ceramic components that simulate dynamic engine operating conditions. The methodology developed is generalized to account for material property variation (on strength distribution and fatigue) as a function of temperature. This allows CARES/Life to analyze components undergoing rapid temperature change in other words, components undergoing thermal shock. In addition, the capability has been developed to perform reliability analysis for components that undergo proof testing involving transient loads. This methodology was developed for environmentally assisted crack growth (crack growth as a function of time and loading), but it will be extended to account for cyclic fatigue (crack growth as a function of load cycles) as well.

The performance of cable braids and terminations to lightning induced transients

NASA Technical Reports Server (NTRS)

Crofts, David

1991-01-01

The latest specification detailing the test waveforms for indirect lightning transients as applied to aircraft wiring systems specify very high voltages and currents. Although considerable data exists for measuring cable screen leakage using such methods as surface transfer impedance and bulk cable injection, there is little data on the likely core transient level that is likely to be induced from these threats. In particular, the new Waveform 5 at very high current levels (10 kA) is reputed to cause severe cable damage. A range of representative cables were made with various screen termination techniques and screening levels. These were tested first to determine their relative screening performance and then they were subjected to lightning transient testing to all the specified waveforms. Core voltages were measured for each test. Tests were also performed on bundles with fewer wires to determine the failure criteria with Waveform 5 and these tests also include flat conductor cables. The test showed that correctly terminated cable bundles performed well in all the tests and would provide a high level of protection to the electronic systems. The use of overbraides, provided the individual screens are well terminated, appears to be unnecessary.

Fragile X Mental Retardation Protein is Required for Programmed Cell Death and Clearance of Developmentally-Transient Peptidergic Neurons

PubMed Central

Gatto, Cheryl L.; Broadie, Kendal

2011-01-01

Fragile X syndrome (FXS), caused by loss of fragile X mental retardation 1 (FMR1) gene function, is the most common heritable cause of intellectual disability and autism spectrum disorders. The FMR1 product (FMRP) is an RNA-binding protein best established to function in activity-dependent modulation of synaptic connections. In the Drosophila FXS disease model, loss of functionally-conserved dFMRP causes synaptic overgrowth and overelaboration in pigment dispersing factor (PDF) peptidergic neurons in the adult brain. Here, we identify a very different component of PDF neuron misregulation in dfmr1 mutants: the aberrant retention of normally developmentally-transient PDF tritocerebral (PDF-TRI) neurons. In wild-type animals, PDF-TRI neurons in the central brain undergo programmed cell death and complete, processive clearance within days of eclosion. In the absence of dFMRP, a defective apoptotic program leads to constitutive maintenance of these peptidergic neurons. We tested whether this apoptotic defect is circuit-specific by examining crustacean cardioactive peptide (CCAP) and bursicon circuits, which are similarly developmentally-transient and normally eliminated immediately post-eclosion. In dfmr1 null mutants, CCAP/bursicon neurons also exhibit significantly delayed clearance dynamics, but are subsequently eliminated from the nervous system, in contrast to the fully persistent PDF-TRI neurons. Thus, the requirement of dFMRP for the retention of transitory peptidergic neurons shows evident circuit specificity. The novel defect of impaired apoptosis and aberrant neuron persistence in the Drosophila FXS model suggests an entirely new level of “pruning” dysfunction may contribute to the FXS disease state. PMID:21596027

Metabolic profile of liver damage in non-cirrhotic virus C and autoimmune hepatitis: A proton decoupled 31P-MRS study.

PubMed

Hakkarainen, Antti; Puustinen, Lauri; Kivisaari, Reetta; Boyd, Sonja; Nieminen, Urpo; Arkkila, Perttu; Lundbom, Nina

2017-05-01

To study liver 31 P MRS, histology, transient elastography, and liver function tests in patients with virus C hepatitis (HCV) or autoimmune hepatitis (AIH) to test the hypothesis that 31 P MR metabolic profile of these diseases differ. 25 patients with HCV (n=12) or AIH (n=13) underwent proton decoupled 31 P MRS spectroscopy performed on a 3.0T MR imager. Intensities of phosphomonoesters (PME) of phosphoethanolamine (PE) and phosphocholine (PC), phosphodiesters (PDE) of glycerophosphoethanolamine (GPE) and glycerophosphocholine (GPC), and γ, α and β resonances of adenosine triphosphate (ATP), and nicotinamide adenine dinucleotide phosphate (NADPH) were determined. Liver stiffness was measured by transient elastography. Inflammation and fibrosis were staged according to METAVIR from biopsy samples. Activities of alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALT) and thromboplastin time (TT) were determined from serum samples. PME had a stronger correlation with AST (z=1.73, p=0.04) and ALT (z=1.77, p=0.04) in HCV than in AIH patients. PME, PME/PDE, PE/GPE correlated positively and PDE negatively with inflammatory activity. PE, PC and PME correlated positively with liver function tests. 31 P-MRS suggests a more serious liver damage in HCV than in AIH with similar histopathological findings. 31 P-MRS is more sensitive in detecting inflammation than fibrosis in the liver. Copyright © 2017 Elsevier B.V. All rights reserved.

Presence of transient hydronephrosis immediately after surgery has a limited influence on renal function 1 year after ileal neobladder construction.

PubMed

Narita, Takuma; Hatakeyama, Shingo; Koie, Takuya; Hosogoe, Shogo; Matsumoto, Teppei; Soma, Osamu; Yamamoto, Hayato; Yoneyama, Tohru; Tobisawa, Yuki; Yoneyama, Takahiro; Hashimoto, Yasuhiro; Ohyama, Chikara

2017-08-31

Urinary tract obstruction and postoperative hydronephrosis are risk factor for renal function deterioration after orthotopic ileal neobladder construction. However, reports of relationship between transient hydronephrosis and renal function are limited. We assess the influence of postoperative transient hydronephrosis on renal function in patients with orthotopic ileal neobladder construction. Between January 2006 and June 2013, we performed radical cystectomy in 164 patients, and 101 received orthotopic ileal neobladder construction. This study included data available from 64 patients with 128 renal units who were enrolled retrospectively. The hydronephrosis grade of each renal unit scored 0-4. The patients were divided into 4 groups according to the grade of hydronephrosis: control, low, intermediate, and high. The grade of postoperative hydronephrosis was compared with renal function 1 month and 1 year after surgery. There were no significant differences in renal function before surgery between groups. One month after surgery, the presence of hydronephrosis was significantly associated with decreased renal function. However, 1 year after urinary diversion hydronephrosis grades were improved significantly, and renal function was comparable between groups. Postoperative hydronephrosis at 1 month had no significant influence on renal function 1 year after ileal neobladder construction. Limitations include retrospective design, short follow-up periods, and a sample composition. The presence of transient hydronephrosis immediately after surgery may have limited influence on renal function 1 year after ileal neobladder construction.

Development of NASA's Sample Cartridge Assembly: Summary of GEDS Design, Development Testing, and Thermal Analyses

NASA Technical Reports Server (NTRS)

O'Connor, Brian; Hernandez, Deborah; Hornsby, Linda; Brown, Maria; Horton-Mullins, Kathryn

2017-01-01

Outline: Background of ISS (International Space Station) Material Science Research Rack; NASA SCA (Sample Cartridge Assembly) Design; GEDS (Gravitational Effects in Distortion in Sintering) Experiment Ampoule Design; Development Testing Summary; Thermal Modeling and Analysis. Summary: GEDS design development challenging (GEDS Ampoule design developed through MUGS (Microgravity) testing; Short duration transient sample processing; Unable to measure sample temperatures); MUGS Development testing used to gather data (Actual LGF (Low Gradient Furnace)-like furnace response; Provided sample for sintering evaluation); Transient thermal model integral to successful GEDS experiment (Development testing provided furnace response; PI (Performance Indicator) evaluation of sintering anchored model evaluation of processing durations; Thermal transient model used to determine flight SCA sample processing profiles).

A study of the transient performance of annular hydrostatic journal bearings in liquid oxygen

NASA Astrophysics Data System (ADS)

Scharrer, J. K.; Tellier, J. G.; Hibbs, R. I.

1992-07-01

A test apparatus was used to simulate a cryogenic turbopump start transient in order to determine the liftoff and touchdown speed and amount of wear of an annular hydrostatic bearing in liquid oxygen. The bearing was made of sterling silver and the journal made of Inconel 718. The target application of this configuration is the pump end bearing of the Space Shuttle Main Engine High Pressure Liquid Oxygen Turbopump. Sixty-one transient cycles were performed in liquid oxygen with an additional three tests in liquid nitrogen to certify the test facility and configuration. The bearing showed no appreciable wear during the testing, and the results indicate that the performance of the bearing was not significantly degraded during the testing.

Test procedures and performance measures sensitive to automobile steering dynamics. [considering operator/vehicle responses

NASA Technical Reports Server (NTRS)

Klein, R. H.; Mcruer, D. T.; Weir, D.

1975-01-01

A maneuver complex and related performance measures used to evaluate driver/vehicle system responses as effected by variations in the directional response characteristics of passenger cars are described. The complex consists of normal and emergency maneuvers (including random and discrete disturbances) which, taken as a whole, represent all classes of steering functions and all modes of driver response behavior. Measures of driver/vehicle system response and performance in regulation tasks included direct describing function measurements and rms yaw velocity. In transient maneuvers, measures such as steering activity and cone strikes were used.

Analysis of transient state in HTS tapes under ripple DC load current

NASA Astrophysics Data System (ADS)

Stepien, M.; Grzesik, B.

2014-05-01

The paper concerns the analysis of transient state (quench transition) in HTS tapes loaded with the current having DC component together with a ripple component. Two shapes of the ripple were taken into account: sinusoidal and triangular. Very often HTS tape connected to a power electronic current supply (i.e. superconducting coil for SMES) that delivers DC current with ripples and it needs to be examined under such conditions. Additionally, measurements of electrical (and thermal) parameters under such ripple excitation is useful to tape characterization in broad range of load currents. The results presented in the paper were obtained using test bench which contains programmable DC supply and National Instruments data acquisition system. Voltage drops and load currents were measured vs. time. Analysis of measured parameters as a function of the current was used to tape description with quench dynamics taken into account. Results of measurements were also used to comparison with the results of numerical modelling based on FEM. Presented provisional results show possibility to use results of measurements in transient state to prepare inverse models of superconductors and their detailed numerical modelling.

Use of electrochemical potential noise to detect initiation and propagation of stress corrosion cracks in a 17-4 PH steel

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

Gonzalez-Rodriguez, J.G.; Salinas-Bravo, V.M.; Garcia-Ochoa, E.

1997-09-01

Corrosion potential transients were associated with nucleation and propagation of stress corrosion cracks in a 17-4 precipitation-hardenable (PH) martensitic stainless steel (SS) during slow strain rate tests (SSRT) at 90 C in deaerated sodium chloride (NaCl) solutions, Test solutions included 20 wt% NaCl at pH 3 and 7, similar to normal and faulted steam turbine environments, respectively. Time series were analyzed using the fast Fourier transform method. At the beginning of straining, the consistent noise behavior was perturbed with small potential transients, probably associated with rupture of the surface oxide layer. After yielding, these transients increased in intensity. At maximummore » load, the transients were still higher in intensity and frequency. These potential transients were related to crack nucleation and propagation. When the steel did not fail by stress corrosion cracking (SCC), such transients were found only at the beginning of the test. The power spectra showed some differences in all cases in roll-off slope and voltage magnitude, but these were not reliable tools to monitor the initiation and propagation of stress corrosion cracks.« less

Attenuation of Ca2+ homeostasis, oxidative stress, and mitochondrial dysfunctions in diabetic rat heart: insulin therapy or aerobic exercise?

PubMed

da Silva, Márcia F; Natali, Antônio J; da Silva, Edson; Gomes, Gilton J; Teodoro, Bruno G; Cunha, Daise N Q; Drummond, Lucas R; Drummond, Filipe R; Moura, Anselmo G; Belfort, Felipe G; de Oliveira, Alessandro; Maldonado, Izabel R S C; Alberici, Luciane C

2015-07-15

We tested the effects of swimming training and insulin therapy, either alone or in combination, on the intracellular calcium ([Ca(2+)]i) homeostasis, oxidative stress, and mitochondrial functions in diabetic rat hearts. Male Wistar rats were separated into control, diabetic, or diabetic plus insulin groups. Type 1 diabetes mellitus was induced by streptozotocin (STZ). Insulin-treated groups received 1 to 4 UI of insulin daily for 8 wk. Each group was divided into sedentary or exercised rats. Trained groups were submitted to swimming (90 min/day, 5 days/wk, 8 wk). [Ca(2+)]i transient in left ventricular myocytes (LVM), oxidative stress in LV tissue, and mitochondrial functions in the heart were assessed. Diabetes reduced the amplitude and prolonged the times to peak and to half decay of the [Ca(2+)]i transient in LVM, increased NADPH oxidase-4 (Nox-4) expression, decreased superoxide dismutase (SOD), and increased carbonyl protein contents in LV tissue. In isolated mitochondria, diabetes increased Ca(2+) uptake, susceptibility to permeability transition pore (MPTP) opening, uncoupling protein-2 (UCP-2) expression, and oxygen consumption but reduced H2O2 release. Swimming training corrected the time course of the [Ca(2+)]i transient, UCP-2 expression, and mitochondrial Ca(2+) uptake. Insulin replacement further normalized [Ca(2+)]i transient amplitude, Nox-4 expression, and carbonyl content. Alongside these benefits, the combination of both therapies restored the LV tissue SOD and mitochondrial O2 consumption, H2O2 release, and MPTP opening. In conclusion, the combination of swimming training with insulin replacement was more effective in attenuating intracellular Ca(2+) disruptions, oxidative stress, and mitochondrial dysfunctions in STZ-induced diabetic rat hearts. Copyright © 2015 the American Physiological Society.

Microthrix parvicella abundance associates with activated sludge settling velocity and rheology - Quantifying and modelling filamentous bulking.

PubMed

Wágner, Dorottya S; Ramin, Elham; Szabo, Peter; Dechesne, Arnaud; Plósz, Benedek Gy

2015-07-01

The objective of this work is to identify relevant settling velocity and rheology model parameters and to assess the underlying filamentous microbial community characteristics that can influence the solids mixing and transport in secondary settling tanks. Parameter values for hindered, transient and compression settling velocity functions were estimated by carrying out biweekly batch settling tests using a novel column setup through a four-month long measurement campaign. To estimate viscosity model parameters, rheological experiments were carried out on the same sludge sample using a rotational viscometer. Quantitative fluorescence in-situ hybridisation (qFISH) analysis, targeting Microthrix parvicella and phylum Chloroflexi, was used. This study finds that M. parvicella - predominantly residing inside the microbial flocs in our samples - can significantly influence secondary settling through altering the hindered settling velocity and yield stress parameter. Strikingly, this is not the case for Chloroflexi, occurring in more than double the abundance of M. parvicella, and forming filaments primarily protruding from the flocs. The transient and compression settling parameters show a comparably high variability, and no significant association with filamentous abundance. A two-dimensional, axi-symmetrical computational fluid dynamics (CFD) model was used to assess calibration scenarios to model filamentous bulking. Our results suggest that model predictions can significantly benefit from explicitly accounting for filamentous bulking by calibrating the hindered settling velocity function. Furthermore, accounting for the transient and compression settling velocity in the computational domain is crucial to improve model accuracy when modelling filamentous bulking. However, the case-specific calibration of transient and compression settling parameters as well as yield stress is not necessary, and an average parameter set - obtained under bulking and good settling conditions - can be used. Copyright © 2015 Elsevier Ltd. All rights reserved.

Transient inactivation of basolateral amygdala during selective satiation disrupts reinforcer devaluation in rats

PubMed Central

West, Elizabeth A.; Forcelli, Patrick A.; Murnen, Alice T.; McCue, David L.; Gale, Karen; Malkova, Ludise

2012-01-01

Basolateral amygdala (BLA) function is critical for flexible, goal-directed behavior, including performance on reinforcer devaluation tasks. Here we tested, in rats, the hypothesis that BLA is critical for conditioned reinforcer devaluation during the period when the primary reinforcer (food) is being devalued (by feeding it to satiety), but not thereafter for guiding behavioral choices. We used a spatially-independent task, which employed two visual cues, each predicting one of two foods. An instrumental action (lever press) was required for reinforcer delivery. After training, rats received BLA or sham lesions, or cannulae implanted in BLA. Under control conditions (sham lesions, saline infusions), devaluation of one food significantly decreased responding to the cue associated with that food, when both cues were presented simultaneously during extinction. BLA lesions impaired this devaluation effect. Transient inactivation of BLA by microinfusion of the GABAA agonist muscimol resulted in an impairment, only when BLA was inactivated during satiation. When muscimol was infused after satiation and, therefore, BLA was inactivated only during the choice test, rats showed no impairment. Thus, BLA is necessary for registering or updating cues to reflect updated reinforcer values, but not for guiding choices once the value has been updated. Our results are the first to describe the contribution of rat BLA to specific components of reinforcer devaluation, and are the first to show impairment in reinforcer devaluation following transient inactivation in the rat. PMID:22845705

Tidal volume single-breath washin of SF6 and CH4 in transient microgravity

NASA Technical Reports Server (NTRS)

Dutrieue, Brigitte; Paiva, Manuel; Verbanck, Sylvia; Le Gouic, Marine; Darquenne, Chantal; Prisk, G. Kim

2003-01-01

We performed tidal volume single-breath washins (SBW) by using tracers of different diffusivity and varied the time spent in microgravity (microG) before the start of the tests to look for time-dependent effects. SF(6) and CH(4) phase III slopes decreased by 35 and 26%, respectively, in microG compared with 1 G (P < 0.05), and the slope difference between gases disappeared. There was no effect of time in microG, suggesting that neither the hypergravity period preceding microG nor the time spent in microG affected gas mixing at volumes near functional residual capacity. In previous studies using SF(6) and He (Lauzon A-M, Prisk GK, Elliott AR, Verbanck S, Paiva M, and West JB. J Appl Physiol 82: 859-865, 1997), the vital capacity SBW showed an increase in slope difference between gases in transient microG, the opposite of the decrease in sustained microG. In contrast, tidal volume SBW showed a decrease in slope difference in both microG conditions. Because it is only the behavior of the more diffusive gas that differed between maneuvers and microG conditions, we speculate that, in the previous vital capacity SBW, the hypergravity period preceding the test in transient microG provoked conformational changes at low lung volumes near the acinar entrance.

Characterization of Regular Wave, Irregular Wave, and Large-Amplitude Wave Group Kinematics in an Experimental Basin

DTIC Science & Technology

2011-02-01

seakeeping was the transient wave technique, developed analytically by Davis and Zarnick (1964). At the David Taylor Model Basin, Davis and Zarnick, and...Gersten and Johnson (1969) applied the transient wave technique to regular wave model experiments for heave and pitch, at zero forward speed. These...tests demonstrated a potential reduction by an order of magnitude of the total necessary testing time. The transient wave technique was also applied to

Behavioral and anatomical consequences of repetitive mild thoracic spinal cord contusion injury in the rat.

PubMed

Jin, Ying; Bouyer, Julien; Haas, Christopher; Fischer, Itzhak

2014-07-01

Moderate and severe spinal cord contusion injuries have been extensively studied, yet much less is known about mild injuries. Mild contusions result in transient functional deficits, proceeding to near-complete recovery, but they may render the spinal cord vulnerable to future injuries. However, to date there have been no appropriate models to study the behavioral consequences, anatomical changes, and susceptibility of a mild contusion to repeated injuries, which may occur in children as well as adults during competitive sport activities. We have developed a novel mild spinal cord contusion injury model characterized by a sequence of transient functional deficits after the first injury and restoration to near-complete motor and sensory function, which is then followed up by a second injury. This model can serve not only to study the effects of repeated injuries on behavioral and anatomical changes, but also to examine the relationship between successive tissue damage and recovery of function. In the present study, we confirmed that mild thoracic spinal cord contusion, utilizing the NYU impactor device, resulted in localized tissue damage, characterized by a cystic cavity and peripheral rim of spared white matter at the injury epicenter, and rapid functional recovery to near-normal levels utilizing several behavioral tests. Repeated injury after 3weeks, when functional recovery has been completed, resulted in worsening of both motor and sensory function, which did not recover to prior levels. Anatomical analyses showed no differences in the volumes of spared white matter, lesion, or cyst, but revealed modest extension of lesion area rostral to the injury epicenter as well as an increase in inflammation and apoptosis. These studies demonstrate that a mild injury model can be used to test efficacy of treatments for repeated injuries and may serve to assist in the formulation of policies and clinical practice regarding mild SCI injury and spinal concussion. Copyright © 2014 Elsevier Inc. All rights reserved.

Transient full-field vibration measurement using spectroscopical stereo photogrammetry.

PubMed

Yue, Kaiduan; Li, Zhongke; Zhang, Ming; Chen, Shan

2010-12-20

Contrasted with other vibration measurement methods, a novel spectroscopical photogrammetric approach is proposed. Two colored light filters and a CCD color camera are used to achieve the function of two traditional cameras. Then a new calibration method is presented. It focuses on the vibrating object rather than the camera and has the advantage of more accuracy than traditional camera calibration. The test results have shown an accuracy of 0.02 mm.

Method of Generating Transient Equivalent Sink and Test Target Temperatures for Swift BAT

NASA Technical Reports Server (NTRS)

Choi, Michael K.

2004-01-01

The NASA Swift mission has a 600-km altitude and a 22 degrees maximum inclination. The sun angle varies from 45 degrees to 180 degrees in normal operation. As a result, environmental heat fluxes absorbed by the Burst Alert Telescope (BAT) radiator and loop heat pipe (LHP) compensation chambers (CCs) vary transiently. Therefore the equivalent sink temperatures for the radiator and CCs varies transiently. In thermal performance verification testing in vacuum, the radiator and CCs radiated heat to sink targets. This paper presents an analytical technique for generating orbit transient equivalent sink temperatures and a technique for generating transient sink target temperatures for the radiator and LHP CCs. Using these techniques, transient target temperatures for the radiator and LHP CCs were generated for three thermal environmental cases: worst hot case, worst cold case, and cooldown and warmup between worst hot case in sunlight and worst cold case in the eclipse, and three different heat transport values: 128 W, 255 W, and 382 W. The 128 W case assumed that the two LHPs transport 255 W equally to the radiator. The 255 W case assumed that one LHP fails so that the remaining LHP transports all the waste heat from the detector array to the radiator. The 382 W case assumed that one LHP fails so that the remaining LHP transports all the waste heat from the detector array to the radiator, and has a 50% design margin. All these transient target temperatures were successfully implemented in the engineering test unit (ETU) LHP and flight LHP thermal performance verification tests in vacuum.

Transient stability enhancement of modern power grid using predictive Wide-Area Monitoring and Control

NASA Astrophysics Data System (ADS)

Yousefian, Reza

This dissertation presents a real-time Wide-Area Control (WAC) designed based on artificial intelligence for large scale modern power systems transient stability enhancement. The WAC using the measurements available from Phasor Measurement Units (PMUs) at generator buses, monitors the global oscillations in the system and optimally augments the local excitation system of the synchronous generators. The complexity of the power system stability problem along with uncertainties and nonlinearities makes the conventional modeling non-practical or inaccurate. In this work Reinforcement Learning (RL) algorithm on the benchmark of Neural Networks (NNs) is used to map the nonlinearities of the system in real-time. This method different from both the centralized and the decentralized control schemes, employs a number of semi-autonomous agents to collaborate with each other to perform optimal control theory well-suited for WAC applications. Also, to handle the delays in Wide-Area Monitoring (WAM) and adapt the RL toward the robust control design, Temporal Difference (TD) is proposed as a solver for RL problem or optimal cost function. However, the main drawback of such WAC design is that it is challenging to determine if an offline trained network is valid to assess the stability of the power system once the system is evolved to a different operating state or network topology. In order to address the generality issue of NNs, a value priority scheme is proposed in this work to design a hybrid linear and nonlinear controllers. The algorithm so-called supervised RL is based on mixture of experts, where it is initialized by linear controller and as the performance and identification of the RL controller improves in real-time switches to the other controller. This work also focuses on transient stability and develops Lyapunov energy functions for synchronous generators to monitor the stability stress of the system. Using such energies as a cost function guarantees the convergence toward optimal post-fault solutions. These energy functions are developed on inter-area oscillations of the system identified online with Prony analysis. Finally, this work investigates the impacts of renewable energy resources, in specific Doubly Fed Induction Generator (DFIG)-based wind turbines, on power system transient stability and control. As the penetration of such resources is increased in transmission power system, neglecting the impacts of them will make the WAC design non-realistic. An energy function is proposed for DFIGs based on their dynamic performance in transient disturbances. Further, this energy is augmented to synchronous generators' energy as a global cost function, which is minimized by the WAC signals. We discuss the relative advantages and bottlenecks of each architecture and methodology using dynamic simulations of several test systems including a 2-area 8 bus system, IEEE 39 bus system, and IEEE 68 bus system in EMTP and real-time simulators. Being nonlinear-based, fast, accurate, and non-model based design, the proposed WAC system shows better transient and damping response when compared to conventional control schemes and local PSSs.

Corona evaluation for 270 volt dc systems

NASA Astrophysics Data System (ADS)

Dunbar, William G.

When designing 270 V dc power system electronics and wiring systems, it is essential to evaluate such corona-initiation-prone parts with bare electrodes as terminations and leads, and to take into account spacings, gas pressures (as a function of maximum altitude), temperature, voltage transients, and insulation coating thickness. Both persistent and intermittent transients are important. Filters and transient suppressors are excellent methods for limiting overvoltage transients in order to prevent corona initiation within a module.

Rolling Resistance of Tires Measured Under Transient and Equilibrium Conditions on Calspan's Tire Research

DOT National Transportation Integrated Search

1976-03-01

Rolling loss tests were performed on 31 different passenger and 4 light truck tires under transient and equilibrium conditions. The tests were designed to determine the effects of load, speed, inflation pressure, tire temperature, slip angle, torque,...

Non-destructive testing of ceramic materials using mid-infrared ultrashort-pulse laser

NASA Astrophysics Data System (ADS)

Sun, S. C.; Qi, Hong; An, X. Y.; Ren, Y. T.; Qiao, Y. B.; Ruan, Liming M.

2018-04-01

The non-destructive testing (NDT) of ceramic materials using mid-infrared ultrashort-pulse laser is investigated in this study. The discrete ordinate method is applied to solve the transient radiative transfer equation in 2D semitransparent medium and the emerging radiative intensity on boundary serves as input for the inverse analysis. The sequential quadratic programming algorithm is employed as the inverse technique to optimize objective function, in which the gradient of objective function with respect to reconstruction parameters is calculated using the adjoint model. Two reticulated porous ceramics including partially stabilized zirconia and oxide-bonded silicon carbide are tested. The retrieval results show that the main characteristics of defects such as optical properties, geometric shapes and positions can be accurately reconstructed by the present model. The proposed technique is effective and robust in NDT of ceramics even with measurement errors.

Assay of Calcium Transients and Synapses in Rat Hippocampal Neurons by Kinetic Image Cytometry and High-Content Analysis: An In Vitro Model System for Postchemotherapy Cognitive Impairment.

PubMed

McDonough, Patrick M; Prigozhina, Natalie L; Basa, Ranor C B; Price, Jeffrey H

2017-07-01

Postchemotherapy cognitive impairment (PCCI) is commonly exhibited by cancer patients treated with a variety of chemotherapeutic agents, including the endocrine disruptor tamoxifen (TAM). The etiology of PCCI is poorly understood. Our goal was to develop high-throughput assay methods to test the effects of chemicals on neuronal function applicable to PCCI. Rat hippocampal neurons (RHNs) were plated in 96- or 384-well dishes and exposed to test compounds (forskolin [FSK], 17β-estradiol [ES]), TAM or fulvestrant [FUL], aka ICI 182,780) for 6-14 days. Kinetic Image Cytometry™ (KIC™) methods were developed to quantify spontaneously occurring intracellular calcium transients representing the activity of the neurons, and high-content analysis (HCA) methods were developed to quantify the expression, colocalization, and puncta formed by synaptic proteins (postsynaptic density protein-95 [PSD-95] and presynaptic protein Synapsin-1 [Syn-1]). As quantified by KIC, FSK increased the occurrence and synchronization of the calcium transients indicating stimulatory effects on RHN activity, whereas TAM had inhibitory effects. As quantified by HCA, FSK also increased PSD-95 puncta and PSD-95:Syn-1 colocalization, whereas ES increased the puncta of both PSD-95 and Syn-1 with little effect on colocalization. The estrogen receptor antagonist FUL also increased PSD-95 puncta. In contrast, TAM reduced Syn-1 and PSD-95:Syn-1 colocalization, consistent with its inhibitory effects on the calcium transients. Thus TAM reduced activity and synapse formation by the RHNs, which may relate to the ability of this agent to cause PCCI. The results illustrate that KIC and HCA can be used to quantify neurotoxic and neuroprotective effects of chemicals in RHNs to investigate mechanisms and potential therapeutics for PCCI.

STEADY STATE MODELING OF THE MINIMUM CRITICAL CORE OF THE TRANSIENT REACTOR TEST FACILITY

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

Anthony L. Alberti; Todd S. Palmer; Javier Ortensi

2016-05-01

With the advent of next generation reactor systems and new fuel designs, the U.S. Department of Energy (DOE) has identified the need for the resumption of transient testing of nuclear fuels. The DOE has decided that the Transient Reactor Test Facility (TREAT) at Idaho National Laboratory (INL) is best suited for future testing. TREAT is a thermal neutron spectrum, air-cooled, nuclear test facility that is designed to test nuclear fuels in transient scenarios. These specific scenarios range from simple temperature transients to full fuel melt accidents. DOE has expressed a desire to develop a simulation capability that will accurately modelmore » the experiments before they are irradiated at the facility. It is the aim for this capability to have an emphasis on effective and safe operation while minimizing experimental time and cost. The multi physics platform MOOSE has been selected as the framework for this project. The goals for this work are to identify the fundamental neutronics properties of TREAT and to develop an accurate steady state model for future multiphysics transient simulations. In order to minimize computational cost, the effect of spatial homogenization and angular discretization are investigated. It was found that significant anisotropy is present in TREAT assemblies and to capture this effect, explicit modeling of cooling channels and inter-element gaps is necessary. For this modeling scheme, single element calculations at 293 K gave power distributions with a root mean square difference of 0.076% from those of reference SERPENT calculations. The minimum critical core configuration with identical gap and channel treatment at 293 K resulted in a root mean square, total core, radial power distribution 2.423% different than those of reference SERPENT solutions.« less

Two-Flux and Green's Function Method for Transient Radiative Transfer in a Semi-Transparent Layer

NASA Technical Reports Server (NTRS)

Siegel, Robert

1995-01-01

A method using a Green's function is developed for computing transient temperatures in a semitransparent layer by using the two-flux method coupled with the transient energy equation. Each boundary of the layer is exposed to a hot or cold radiative environment, and is heated or cooled by convection. The layer refractive index is larger than one, and the effect of internal reflections is included with the boundaries assumed diffuse. The analysis accounts for internal emission, absorption, heat conduction, and isotropic scattering. Spectrally dependent radiative properties are included, and transient results are given to illustrate two-band spectral behavior with optically thin and thick bands. Transient results using the present Green's function method are verified for a gray layer by comparison with a finite difference solution of the exact radiative transfer equations; excellent agreement is obtained. The present method requires only moderate computing times and incorporates isotropic scattering without additional complexity. Typical temperature distributions are given to illustrate application of the method by examining the effect of strong radiative heating on one side of a layer with convective cooling on the other side, and the interaction of strong convective heating with radiative cooling from the layer interior.

A microcomputer-based testing station for dynamic and static testing of protective relay systems

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

Lee, W.J.; Li, R.J.; Gu, J.C.

1995-12-31

Dynamic and static relay performance testing before installation in the field is a subject of great interest to utility relay engineers. The common practice in utility testing of new relays is to put the new unit to be tested in parallel with an existing functioning relay in the system, wait until an actual transient occurs and then observe and analyze the performance of new relay. It is impossible to have a thorough test of the protective relay system through this procedure. An equipment, Microcomputer-Based Testing Station (or PC-Based Testing Station), that can perform both static and dynamic testing of themore » relay is described in this paper. The Power System Simulation Laboratory at the University of Texas at Arlington is a scaled-down, three-phase, physical power system which correlates well with the important components for a real power system and is an ideal facility for the dynamic and static testing of protective relay systems. A brief introduction to the configuration of this laboratory is presented. Test results of several protective functions by using this laboratory illustrate the usefulness of this test set-up.« less

Apparatus and method for defect testing of integrated circuits

DOEpatents

Cole, Jr., Edward I.; Soden, Jerry M.

2000-01-01

An apparatus and method for defect and failure-mechanism testing of integrated circuits (ICs) is disclosed. The apparatus provides an operating voltage, V.sub.DD, to an IC under test and measures a transient voltage component, V.sub.DDT, signal that is produced in response to switching transients that occur as test vectors are provided as inputs to the IC. The amplitude or time delay of the V.sub.DDT signal can be used to distinguish between defective and defect-free (i.e. known good) ICs. The V.sub.DDT signal is measured with a transient digitizer, a digital oscilloscope, or with an IC tester that is also used to input the test vectors to the IC. The present invention has applications for IC process development, for the testing of ICs during manufacture, and for qualifying ICs for reliability.

Space Shuttle Projects

NASA Image and Video Library

1987-07-01

A forward segment is being lowered into the Transient Pressure Test Article (TPTA) test stand at the Marshall Space Flight Center (MSFC) east test area. The TPTA test stand, 14-feet wide, 27-feet long, and 33-feet high, was built in 1987 to provide data to verify the sealing capability of the redesign solid rocket motor (SRM) field and nozzle joints. The test facility applies pressure, temperature, and external loads to a short stack of solid rocket motor hardware. The simulated SRM ignition pressure and temperature transients are achieved by firing a small amount of specially configured solid propellant. The pressure transient is synchronized with external programmable dynamic loads that simulate lift off loads at the external tank attach points. Approximately one million pounds of dead weight on top of the test article simulates the weight of the other Shuttle elements.

Space Shuttle Projects

NASA Image and Video Library

1987-07-01

A forward segment is being lowered into the Transient Pressure Test Article (TPTA) test stand at thw Marshall Space Flight Center (MSFC) east test area. The TPTA test stand, 14-feet wide, 27-feet long, and 33-feet high, was built in 1987 to provide data to verify the sealing capability of the redesign solid rocket motor (SRM) field and nozzle joints. The test facility applies pressure, temperature, and external loads to a short stack of solid rocket motor hardware. The simulated SRM ignition pressure and temperature transients are achieved by firing a small amount of specially configured solid propellant. The pressure transient is synchronized with external programmable dynamic loads that simulate lift off loads at the external tank attach points. Approximately one million pounds of dead weight on top of the test article simulates the weight of the other Shuttle elements.

Transient Lift Off Testing Results for a Radial Hybrid Bearing

DTIC Science & Technology

2009-05-01

Speed Hydrostatic Bearings,” ASME Journal of Tribology, Vol. 116, n2, 1994, pp. 337-344. [2] Scharrer, J. K., Tellier , J. and Hibbs, R., “A Study of... Tellier , J. and Hibbs, R., “A Study of the Transient Performance of Hydrostatic Journal Bearings: Part II-Experimental Results,” STLE Paper 91-TC-3B-2...1991. [4] Scharrer, J., Tellier , J. and Hibbs, R., “Start Transient Testing of an Annular Hydrostatic Bearing in Liquid Oxygen,” AIAA Paper 92-3404

Transient Lift-Off Test Results for an Experimental Hybrid Bearing in Air

DTIC Science & Technology

2009-12-01

High-Speed Hydrostatic Bearings,” ASME Journal of Tribology, Vol. 116, n2, 1994, pp. 337-344. [2] Scharrer, J.K., Tellier , J. and Hibbs, R., “A...J.K., Tellier , J. and Hibbs, R., “A Study of the Transient Performance of Hydrostatic Journal Bearings: Part II-Experimental Results,” STLE Paper 91...TC- 3B-2, 1991. [4] Sharrer, J., Tellier , J. and Hibbs, R., “Start Transient Testing of an Annular Hydrostatic Bearing in Liquid Oxygen,” AIAA

Transient analysis of 1D inhomogeneous media by dynamic inhomogeneous finite element method

NASA Astrophysics Data System (ADS)

Yang, Zailin; Wang, Yao; Hei, Baoping

2013-12-01

The dynamic inhomogeneous finite element method is studied for use in the transient analysis of onedimensional inhomogeneous media. The general formula of the inhomogeneous consistent mass matrix is established based on the shape function. In order to research the advantages of this method, it is compared with the general finite element method. A linear bar element is chosen for the discretization tests of material parameters with two fictitious distributions. And, a numerical example is solved to observe the differences in the results between these two methods. Some characteristics of the dynamic inhomogeneous finite element method that demonstrate its advantages are obtained through comparison with the general finite element method. It is found that the method can be used to solve elastic wave motion problems with a large element scale and a large number of iteration steps.

Surge detection on an automotive turbocharger during transient phases

NASA Astrophysics Data System (ADS)

Deligant, M.; Danlos, A.; Podevin, P.; Clenci, A.; Guilain, S.

2017-10-01

The surge limit on automotive turbocharger needs to be avoided to prevent operations with pressure and mass flow oscillations. Mild surge is accompanied by noise which is disturbing. Deep surge can cause significant loss of engine power and severe drivability issues. It is necessary to know the stationary limit in order to match a turbocharger with an engine, ensuring enough surge margin. However, this choice does not guarantee surge free operation during transient functioning. In this paper, the surge onset of a compressor while closing a downstream valve is studied. Various tests have been carried out varying the closing time, the position of the initial operating point and the volume of the circuit. The inlet and outlet signals of physical parameters are analyzed with spectral and temporal methods in order to define the instant of the surge occurrence.

Direct conversion of solar energy to thermal energy

NASA Astrophysics Data System (ADS)

Sizmann, Rudolf

1986-12-01

Selective coatings (cermets) were produced by simultaneous evaporation of copper and silicon dioxide, and analyzed by computer assisted spectral photometers and ellipsometers; hemispherical emittance was measured. Steady state test procedures for covered and uncovered collectors were investigated. A method for evaluating the transient behavior of collectors was developed. The derived transfer functions describe their transient behavior. A stochastic approach was used for reducing the meteorological data volume. Data sets which are statistically equivalent to the original data can be synthesized. A simulation program for solar systems using analytical solutions of differential equations was developed. A large solar DHW system was optimized by a detailed modular simulation program. A microprocessor assisted data aquisition records the four characteristics of solar cells and solar cell systems in less than 10 msec. Measurements of a large photovoltaic installation (50 sqm) are reported.

Transiently disordered tails accelerate folding of globular proteins.

PubMed

Mallik, Saurav; Ray, Tanaya; Kundu, Sudip

2017-07-01

Numerous biological proteins exhibit intrinsic disorder at their termini, which are associated with multifarious functional roles. Here, we show the surprising result that an increased percentage of terminal short transiently disordered regions with enhanced flexibility (TstDREF) is associated with accelerated folding rates of globular proteins. Evolutionary conservation of predicted disorder at TstDREFs and drastic alteration of folding rates upon point-mutations suggest critical regulatory role(s) of TstDREFs in shaping the folding kinetics. TstDREFs are associated with long-range intramolecular interactions and the percentage of native secondary structural elements physically contacted by TstDREFs exhibit another surprising positive correlation with folding kinetics. These results allow us to infer probable molecular mechanisms behind the TstDREF-mediated regulation of folding kinetics that challenge protein biochemists to assess by direct experimental testing. © 2017 Federation of European Biochemical Societies.

Medial olivocochlear function in children with poor speech-in-noise performance and language disorder.

PubMed

Rocha-Muniz, Caroline Nunes; Mamede Carvallo, Renata Mota; Schochat, Eliane

2017-05-01

Contralateral masking of transient-evoked otoacoustic emissions is a phenomenon that suggests an inhibitory effect of the olivocochlear efferent auditory pathway. Many studies have been inconclusive in demonstrating a clear connection between this system and a behavioral speech-in-noise listening skill. The purpose of this study was to investigate the activation of a medial olivocochlear (MOC) efferent in children with poor speech-in-noise (PSIN) performance and children with language impairment and PSIN (SLI + PSIN). Transient evoked otoacoustic emissions (TEOAEs) with and without contralateral white noise were tested in 52 children (between 6 and 12 years). These children were arranged in three groups: typical development (TD) (n = 25), PSIN (n = 14) and SLI + PSI (n = 13). PSIN and SLI + PSI groups presented reduced otoacoustic emission suppression in comparison with the TD group. Our finding suggests differences in MOC function among children with typical development and children with poor SIN and language problems. Copyright © 2017 Elsevier B.V. All rights reserved.

Two-Flux Green's Function Analysis for Transient Spectral Radiation in a Composite

NASA Technical Reports Server (NTRS)

Siegel, Robert

1996-01-01

An analysis is developed for obtaining transient temperatures in a two-layer semitransparent composite with spectrally dependent properties. Each external boundary of the composite is subjected to radiation and convection. The two-flux radiative transfer equations are solved by deriving a Green's function. This yields the local radiative heat source needed to numerically solve the transient energy equation. An advantage of the two-flux method is that isotropic scattering is included without added complexity. The layer refractive indices are larger than one. This produces internal reflections at the boundaries and the internal interface; the reflections are assumed diffuse. Spectral results using the Green's function method are verified by comparing with numerical solutions using the exact radiative transfer equations. Transient temperature distributions are given to illustrate the effect of radiative heating on one side of a composite with external convective cooling. The protection of a material from incident radiation is illustrated by adding scattering to the layer adjacent to the radiative source.

Transient Stability Output Margin Estimation Based on Energy Function Method

NASA Astrophysics Data System (ADS)

Miwa, Natsuki; Tanaka, Kazuyuki

In this paper, a new method of estimating critical generation margin (CGM) in power systems is proposed from the viewpoint of transient stability diagnostic. The proposed method has the capability to directly compute the stability limit output for a given contingency based on transient energy function method (TEF). Since CGM can be directly obtained by the limit output using estimated P-θ curves and is easy to understand, it is more useful rather than conventional critical clearing time (CCT) of energy function method. The proposed method can also estimate CGM as its negative value that means unstable in present load profile, then negative CGM can be directly utilized as generator output restriction. The proposed method is verified its accuracy and fast solution ability by applying to simple 3-machine model and IEEJ EAST10-machine standard model. Furthermore the useful application to severity ranking of transient stability for a lot of contingency cases is discussed by using CGM.

Vestibulo-ocular and vestibulospinal function before and after cochlear implant surgery

NASA Technical Reports Server (NTRS)

Black, F. O.; Lilly, D. J.; Peterka, R. J.; Fowler, L. P.; Simmons, F. B.

1987-01-01

Vestibular function in cochlear implant candidates varies from normal to total absence of function. In patients with intact vestibular function preoperatively, invasion of the otic capsule places residual vestibular function at risk. Speech-processing strategies that result in large amplitude electrical transients or strategies that employ high amplitude broad frequency carrier signals have the potential for disrupting vestibular function. Five patients were tested with and without electrical stimulation via cochlear electrodes. Two patients experienced subjective vestibular effects that were quickly resolved. No long-term vestibular effects were noted for the two types of second generation cochlear implants evaluated. Histopathological findings from another patient, who had electrically generated vestibular reflex responses to intramodiolar electrodes, indicated that responses elicited were a function of several variables including electrode location, stimulus intensity, stimulus amplitude, and stimulus frequency. Differential auditory, vestibulocolic, and vestibulospinal reflexes were demonstrated from the same electrode as a function of stimulus amplitude, frequency, and duration.

Loss of feed flow, steam generator tube rupture and steam line break thermohydraulic experiments

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

Mendler, O J; Takeuchi, K; Young, M Y

1986-10-01

The Westinghouse Model Boiler No. 2 (MB-2) steam generator test model at the Engineering Test Facility in Tampa, Florida, was reinstrumented and modified for performing a series of tests simulating steam generator accident transients. The transients simulated were: loss of feed flow, steam generator tube rupture, and steam line break events. This document presents a description of (1) the model boiler and the associated test facility, (2) the tests performed, and (3) the analyses of the test results.

Impacts Analyses Supporting the National Environmental Policy Act Environmental Assessment for the Resumption of Transient Testing Program

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

Schafer, Annette L.; Brown, LLoyd C.; Carathers, David C.

2014-02-01

This document contains the analysis details and summary of analyses conducted to evaluate the environmental impacts for the Resumption of Transient Fuel and Materials Testing Program. It provides an assessment of the impacts for the two action alternatives being evaluated in the environmental assessment. These alternatives are (1) resumption of transient testing using the Transient Reactor Test Facility (TREAT) at Idaho National Laboratory (INL) and (2) conducting transient testing using the Annular Core Research Reactor (ACRR) at Sandia National Laboratory in New Mexico (SNL/NM). Analyses are provided for radiologic emissions, other air emissions, soil contamination, and groundwater contamination that couldmore » occur (1) during normal operations, (2) as a result of accidents in one of the facilities, and (3) during transport. It does not include an assessment of the biotic, cultural resources, waste generation, or other impacts that could result from the resumption of transient testing. Analyses were conducted by technical professionals at INL and SNL/NM as noted throughout this report. The analyses are based on bounding radionuclide inventories, with the same inventories used for test materials by both alternatives and different inventories for the TREAT Reactor and ACRR. An upper value on the number of tests was assumed, with a test frequency determined by the realistic turn-around times required between experiments. The estimates provided for impacts during normal operations are based on historical emission rates and projected usage rates; therefore, they are bounding. Estimated doses for members of the public, collocated workers, and facility workers that could be incurred as a result of an accident are very conservative. They do not credit safety systems or administrative procedures (such as evacuation plans or use of personal protective equipment) that could be used to limit worker doses. Doses estimated for transportation are conservative and are based on transport of the bounding radiologic inventory that will be contained in any given test. The transportation analysis assumes all transports will contain the bounding inventory.« less

Euthyroid ''thyroxine toxicosis''

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

Mankikar, G.D.; Clark, A.N.

A survey was made of thyroid function tests on 1,153 patients screened for thyroid disease during a two-year period in a Geriatric Department; 13 percent of the test results fell outside the normal range. Of 88 patients who showed above-normal results, only 12 presented with clinical features of thyrotoxicosis. In 37 patients, the biochemical findings indicated euthyroid ''thyroxine toxicosis''; high values were found for serum thyroxine (T4) and the free thyroxine index (FT4I) but there were no clinical signs or symptoms of thyrotoxicosis; the values reverted to normal within one to three weeks. This pattern was seen also in 7more » examples of T4-treated hypothyroidism. (Overall, the test findings indicated 61 cases of hypothyroidism.) The significance of this transient increase in T4 and FT4I values is discussed. The false positive results suggest that, when laboratory findings are not compatible with the clinical signs, the thyroid function tests should be repeated after another two weeks.« less

Inferring the Mode of Selection from the Transient Response to Demographic Perturbations

NASA Astrophysics Data System (ADS)

Balick, Daniel; Do, Ron; Reich, David; Sunyaev, Shamil

2014-03-01

Despite substantial recent progress in theoretical population genetics, most models work under the assumption of a constant population size. Deviations from fixed population sizes are ubiquitous in natural populations, many of which experience population bottlenecks and re-expansions. The non-equilibrium dynamics introduced by a large perturbation in population size are generally viewed as a confounding factor. In the present work, we take advantage of the transient response to a population bottleneck to infer features of the mode of selection and the distribution of selective effects. We develop an analytic framework and a corresponding statistical test that qualitatively differentiates between alleles under additive and those under recessive or more general epistatic selection. This statistic can be used to bound the joint distribution of selective effects and dominance effects in any diploid sexual organism. We apply this technique to human population genetic data, and severely restrict the space of allowed selective coefficients in humans. Additionally, one can test a set of functionally or medically relevant alleles for the primary mode of selection, or determine the local regional variation in dominance coefficients along the genome.

Distinct Neural Circuits Support Transient and Sustained Processes in Prospective Memory and Working Memory

PubMed Central

West, Robert; Braver, Todd

2009-01-01

Current theories are divided as to whether prospective memory (PM) involves primarily sustained processes such as strategic monitoring, or transient processes such as the retrieval of intentions from memory when a relevant cue is encountered. The current study examined the neural correlates of PM using a functional magnetic resonance imaging design that allows for the decomposition of brain activity into sustained and transient components. Performance of the PM task was primarily associated with sustained responses in a network including anterior prefrontal cortex (lateral Brodmann area 10), and these responses were dissociable from sustained responses associated with active maintenance in working memory. Additionally, the sustained responses in anterior prefrontal cortex correlated with faster response times for prospective responses. Prospective cues also elicited selective transient activity in a region of interest along the right middle temporal gyrus. The results support the conclusion that both sustained and transient processes contribute to efficient PM and provide novel constraints on the functional role of anterior PFC in higher-order cognition. PMID:18854581

Study of clad ballooning and rupture behaviour of Indian PHWR fuel pins under transient heating condition in steam environment

NASA Astrophysics Data System (ADS)

Sawarn, Tapan K.; Banerjee, Suparna; Sheelvantra, Smita S.; Singh, J. L.; Bhasin, Vivek

2017-11-01

This paper presents the results of the investigation on the deformation and rupture characteristics of Indian pressurized heavy water reactor (IPHWR) fuel pins under simulated loss of coolant accident (LOCA) condition in steam environment. Transient heating experiments were carried out on single fuel pin internally pressurized with argon gas in the range 3-70 bar. Effect of internal pressure on burst temperature, influence of burst temperature on the circumferential strain and rupture opening area were also studied. Two circumferential strain maxima at the burst temperatures of 740 & ∼979 °C and a minimum at the burst temperature of ∼868 °C were observed. It was found that oxidation had considerable effect on the burst behavior. Test data were used to derive a direct empirical correlation for burst stress exclusively as a function of temperature. The ballooning and rupture behaviours in steam and argon environments have been compared. Experimental data were examined against various correlations using Erbacher equation and author's previous correlation in argon. A second burst correlation has also been developed combining the equation in argon from the previous work of the authors and an exponential factor with oxygen content as a parameter assuming the burst stress to be a function of both temperature and oxygen concentration. The burst temperatures predicted by this empirical correlation are in good agreement with the test data.

“Characterizing Factors Influencing SI Engine Transient Fuel Consumption for Vehicle Simulation in ALPHA,” SAE Technical Paper 2017-01-0533, 2017, doi:10.4271/2017-01-0533, Dekraker, P., Stuhldreher, M., Kim, Y. (SwRI).

EPA Pesticide Factsheets

This paper examines a) typical transient engine operation encountered over the EPA city and highway drive cycles, b) EPA’s vehicle and engine testing to characterize that transient fuel usage, and c) changes made to ALPHA to better model transient engine

Real-time detection of transients in OGLE-IV with application of machine learning

NASA Astrophysics Data System (ADS)

Klencki, Jakub; Wyrzykowski, Łukasz

2016-06-01

The current bottleneck of transient detection in most surveys is the problem of rejecting numerous artifacts from detected candidates. We present a triple-stage hierarchical machine learning system for automated artifact filtering in difference imaging, based on self-organizing maps. The classifier, when tested on the OGLE-IV Transient Detection System, accepts 97% of real transients while removing up to 97.5% of artifacts.

Evaluation of Start Transient Oscillations with the J-2X Engine Gas Generator Assembly

NASA Technical Reports Server (NTRS)

Hulka, J. R.; Morgan, C. J.; Casiano, M. J.

2015-01-01

During development of the gas generator for the liquid oxygen/liquid hydrogen propellant J-2X rocket engine, distinctive and oftentimes high-amplitude pressure oscillations and hardware vibrations occurred during the start transient of nearly every workhorse gas generator assembly test, as well as during many tests of engine system hardware. These oscillations appeared whether the steady-state conditions exhibited stable behavior or not. They occurred similarly with three different injector types, and with every combustion chamber configuration tested, including chamber lengths ranging over a 5:1 range, several different nozzle types, and with or without a side branch line simulating a turbine spin start gas supply line. Generally, two sets of oscillations occurred, one earlier in the start transient and at higher frequencies, and the other almost immediately following and at lower frequencies. Multiple dynamic pressure measurements in the workhorse combustion chambers indicated that the oscillations were associated with longitudinal acoustic modes of the combustion chambers, with the earlier and higher frequency oscillation usually related to the second longitudinal acoustic mode and the later and lower frequency oscillation usually related to the first longitudinal acoustic mode. Given that several early development gas generator assemblies exhibited unstable behavior at frequencies near the first longitudinal acoustic modes of longer combustion chambers, the start transient oscillations are presumed to provide additional insight into the nature of the combustion instability mechanisms. Aspects of the steadystate oscillations and combustion instabilities from development and engine system test programs have been reported extensively in the three previous JANNAF Liquid Propulsion Subcommittee meetings (see references below). This paper describes the hardware configurations, start transient sequence operations, and transient and dynamic test data during the start transient. The implications of these results on previous analyses and understanding of the combustion instability observed during steady-state conditions, especially the effects of injector influences, is discussed.

Capabilities Development for Transient Testing of Advanced Nuclear Fuels at TREAT

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

Woolstenhulme, N. E.; Baker, C. C.; Bess, J. D.

2016-09-01

The TREAT facility is a unique capability at the Idaho National Laboratory currently being prepared for resumption of nuclear transient testing. Accordingly, designs for several transient irradiation tests are being pursued to enable development of advanced nuclear fuels and materials. In addition to the reactor itself, the foundation for TREAT’s capabilities also include a suite of irradiation vehicles and supporting infrastructure to provide the desired specimen boundary conditions while supporting a variety of instrumentation needs. The challenge of creating these vehicles, especially since many of the modern data needs were not historically addressed in TREAT experiment vehicles, has necessitated amore » sizeable engineering effort. This effort is currently underway and maturing rapidly. This paper summarizes the status, future plans, and rationale for TREAT experiment vehicle capabilities. Much of the current progress is focused around understanding and demonstrating the behavior of fuel design with enhanced accident tolerance in water-cooled reactors. Additionally, several related efforts are underway to facilitate transient testing in liquid sodium, inert gas, and steam environments. This paper discusses why such a variety of capabilities are needed, outlines plans to accomplish them, and describes the relationship between transient data needs and the irradiation hardware that will support the gathering of this information.« less

Dose-dependent suppression by ethanol of transient auditory 40-Hz response.

PubMed

Jääskeläinen, I P; Hirvonen, J; Saher, M; Pekkonen, E; Sillanaukee, P; Näätänen, R; Tiitinen, H

2000-02-01

Acute alcohol (ethanol) challenge is known to induce various cognitive disturbances, yet the neural basis of the effect is poorly known. The auditory transient evoked gamma-band (40-Hz) oscillatory responses have been suggested to be associated with various perceptual and cognitive functions in humans; however, alcohol effects on auditory 40-Hz responses have not been investigated to date. The objective of the study was to test the dose-related impact of alcohol on auditory transient evoked 40-Hz responses during a selective-attention task. Ten healthy social drinkers ingested, in four separate sessions, 0.00, 0. 25, 0.50, or 0.75 g/kg of 10% (v/v) alcohol solution. The order of the sessions was randomized and a double-blind procedure was employed. During a selective attention task, 300-Hz standard and 330-Hz deviant tones were presented to the left ear, and 1000-Hz standards and 1100-Hz deviants to the right ear of the subjects (P=0. 425 for each standard, P=0.075 for each deviant). The subjects attended to a designated ear, and were to detect the deviants therein while ignoring tones to the other ear. The auditory transient evoked 40-Hz responses elicited by both the attended and unattended standard tones were significantly suppressed by the 0.50 and 0.75 g/kg alcohol doses. Alcohol suppresses auditory transient evoked 40-Hz oscillations already with moderate blood alcohol concentrations. Given the putative role of gamma-band oscillations in cognition, this finding could be associated with certain alcohol-induced cognitive deficits.

REVIEWS OF TOPICAL PROBLEMS: Nonlinear dynamics of the brain: emotion and cognition

NASA Astrophysics Data System (ADS)

Rabinovich, Mikhail I.; Muezzinoglu, M. K.

2010-07-01

Experimental investigations of neural system functioning and brain activity are standardly based on the assumption that perceptions, emotions, and cognitive functions can be understood by analyzing steady-state neural processes and static tomographic snapshots. The new approaches discussed in this review are based on the analysis of transient processes and metastable states. Transient dynamics is characterized by two basic properties, structural stability and information sensitivity. The ideas and methods that we discuss provide an explanation for the occurrence of and successive transitions between metastable states observed in experiments, and offer new approaches to behavior analysis. Models of the emotional and cognitive functions of the brain are suggested. The mathematical object that represents the observed transient brain processes in the phase space of the model is a structurally stable heteroclinic channel. The possibility of using the suggested models to construct a quantitative theory of some emotional and cognitive functions is illustrated.

Dynamic and Transient Performance of Turbofan/Turboshaft Convertible Engine With Variable Inlet Guide Vanes

NASA Technical Reports Server (NTRS)

McArdle, Jack G.; Barth, Richard L.; Wenzel, Leon M.; Biesiadny, Thomas J.

1996-01-01

A convertible engine called the CEST TF34, using the variable inlet guide vane method of power change, was tested on an outdoor stand at the NASA Lewis Research Center with a waterbrake dynamometer for the shaft load. A new digital electronic system, in conjunction with a modified standard TF34 hydromechanical fuel control, kept engine operation stable and safely within limits. All planned testing was completed successfully. Steady-state performance and acoustic characteristics were reported previously and are referenced. This report presents results of transient and dynamic tests. The transient tests measured engine response to several rapid changes in thrust and torque commands at constant fan (shaft) speed. Limited results from dynamic tests using the pseudorandom binary noise technique are also presented. Performance of the waterbrake dynamometer is discussed in an appendix.

Terminal Transient Phase of Chaotic Transients

NASA Astrophysics Data System (ADS)

Lilienkamp, Thomas; Parlitz, Ulrich

2018-03-01

Transient chaos in spatially extended systems can be characterized by the length of the transient phase, which typically grows quickly with the system size (supertransients). For a large class of these systems, the chaotic phase terminates abruptly, without any obvious precursors in commonly used observables. Here we investigate transient spatiotemporal chaos in two different models of this class. By probing the state space using perturbed trajectories we show the existence of a "terminal transient phase," which occurs prior to the abrupt collapse of chaotic dynamics. During this phase the impact of perturbations is significantly different from the earlier transient and particular patterns of (non)susceptible regions in state space occur close to the chaotic trajectories. We therefore hypothesize that even without perturbations proper precursors for the collapse of chaotic transients exist, which might be highly relevant for coping with spatiotemporal chaos in cardiac arrhythmias or brain functionality, for example.

Posttest data analysis of FIST experimental TRAC-BD1/MOD1 power transient experiment

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

Wheatley, P.D.; Wagner, K.C.

The FIST power transient test 6PMC2 was analyzed to further the understanding of the FIST facility and provide an assessment of TRAC-BD1/MOD1. FIST power transient 6PMC2 investigated the thermal-hydraulic response following inadvertent closure of the main steam isolation valve and the subsequent failure of the reactor to scram. Failure of the high pressure core spray system was also assumed, resulting in only the reactor core isolation cooling flow for inventory makeup during the transient. The experiment was a sensitivity study with relatively high core power and low makeup rates. This study provides one of the first opportunities to assess TRAC-BD1/MOD1more » under power transient and natural circulation conditions with data from a facility with prototypical BWR geometry. The power transient test was analyzed with emphasis on the following phenomena: (a) the system pressure response, (b) the natural circulation flows and rates, and (c) the heater rod cladding temperature response. Based on the results of this study, TRAC-BD1/MOD1 can be expected to calculate the thermal-hydraulic behavior of a BWR during a power transient.« less

Systems-level computational modeling demonstrates fuel selection switching in high capacity running and low capacity running rats

PubMed Central

Qi, Nathan R.

2018-01-01

High capacity and low capacity running rats, HCR and LCR respectively, have been bred to represent two extremes of running endurance and have recently demonstrated disparities in fuel usage during transient aerobic exercise. HCR rats can maintain fatty acid (FA) utilization throughout the course of transient aerobic exercise whereas LCR rats rely predominantly on glucose utilization. We hypothesized that the difference between HCR and LCR fuel utilization could be explained by a difference in mitochondrial density. To test this hypothesis and to investigate mechanisms of fuel selection, we used a constraint-based kinetic analysis of whole-body metabolism to analyze transient exercise data from these rats. Our model analysis used a thermodynamically constrained kinetic framework that accounts for glycolysis, the TCA cycle, and mitochondrial FA transport and oxidation. The model can effectively match the observed relative rates of oxidation of glucose versus FA, as a function of ATP demand. In searching for the minimal differences required to explain metabolic function in HCR versus LCR rats, it was determined that the whole-body metabolic phenotype of LCR, compared to the HCR, could be explained by a ~50% reduction in total mitochondrial activity with an additional 5-fold reduction in mitochondrial FA transport activity. Finally, we postulate that over sustained periods of exercise that LCR can partly overcome the initial deficit in FA catabolic activity by upregulating FA transport and/or oxidation processes. PMID:29474500

Reusable rocket engine intelligent control system framework design, phase 2

NASA Technical Reports Server (NTRS)

Nemeth, ED; Anderson, Ron; Ols, Joe; Olsasky, Mark

1991-01-01

Elements of an advanced functional framework for reusable rocket engine propulsion system control are presented for the Space Shuttle Main Engine (SSME) demonstration case. Functional elements of the baseline functional framework are defined in detail. The SSME failure modes are evaluated and specific failure modes identified for inclusion in the advanced functional framework diagnostic system. Active control of the SSME start transient is investigated, leading to the identification of a promising approach to mitigating start transient excursions. Key elements of the functional framework are simulated and demonstration cases are provided. Finally, the advanced function framework for control of reusable rocket engines is presented.

Transient Pressure Test Article Test Program

NASA Technical Reports Server (NTRS)

Vibbart, Charles M.

1989-01-01

The Transient Pressure Test Article (TPTA) test program is being conducted at a new test facility located in the East Test Area at the National Aeronautics and Space Administration's (NASA's) Marshall Space Flight Center (MSFC) in Huntsville, Alabama. This facility, along with the special test equipment (STE) required for facility support, was constructed specifically to test and verify the sealing capability of the Redesigned Solid Rocket Motor (RSRM) field, igniter, and nozzle joints. The test article consists of full scale RSRM hardware loaded with inert propellant and assembled in a short stack configuration. The TPTA is pressurized by igniting a propellant cartridge capable of inducing a pressure rise rate which stimulates the ignition transient that occurs during launch. Dynamic loads are applied during the pressure cycle to simulate external tank attach (ETA) strut loads present on the ETA ring. Sealing ability of the redesigned joints is evaluated under joint movement conditions produced by these combined loads since joint sealing ability depends on seal resilience velocity being greater than gap opening velocity. Also, maximum flight dynamic loads are applied to the test article which is either pressurized to 600 psia using gaseous nitrogen (GN2) or applied to the test article as the pressure decays inside the test article on the down cycle after the ignition transient cycle. This new test facility is examined with respect to its capabilities. In addition, both the topic of test effectiveness versus space vehicle flight performance and new aerospace test techniques, as well as a comparison between the old SRM design and the RSRM are presented.

Transient times in linear metabolic pathways under constant affinity constraints.

PubMed

Lloréns, M; Nuño, J C; Montero, F

1997-10-15

In the early seventies, Easterby began the analytical study of transition times for linear reaction schemes [Easterby (1973) Biochim. Biophys. Acta 293, 552-558]. In this pioneer work and in subsequent papers, a state function (the transient time) was used to measure the period before the stationary state, for systems constrained to work under both constant and variable input flux, was reached. Despite the undoubted usefulness of this quantity to describe the time-dependent features of these kinds of systems, its application to the study of chemical reactions under other constraints is questionable. In the present work, a generalization of these magnitudes to linear metabolic pathways functioning under a constant-affinity constraint is carried out. It is proved that classical definitions of transient times do not reflect the actual properties of the transition to the steady state in systems evolving under this restriction. Alternatively, a more adequate framework for interpretation of the transient times for systems with both constant and variable input flux is suggested. Within this context, new definitions that reflect more accurately the transient characteristics of constant affinity systems are stated. Finally, the meaning of these transient times is discussed.

Transient oxidative stress and inflammation after intraperitoneal administration of multiwalled carbon nanotubes functionalized with single strand DNA in rats

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

Clichici, Simona, E-mail: simonaclichici@yahoo.com; Biris, Alexandru Radu; Tabaran, Flaviu

2012-03-15

Multi-walled carbon nanotubes (MWCNTs) are widely used for nanotechnology. Their impact on living organisms is, however, not entirely clarified. Oxidative stress and inflammation seem to be the key mechanisms involved in MWCNTs' cytotoxicity. Until present, pulmonary and skin models were the main tested experimental designs to assess carbon nanotubes' toxicity. The systemic administration of MWCNTs is essential, with respect for future medical applications. Our research is performed on Wistar rats and is focused on the dynamics of oxidative stress parameters in blood and liver and pro-inflammatory cytokines in liver, after single dose (270 mg l{sup −1}) ip administration of MWCNTsmore » (exterior diameter 15–25 nm, interior diameter 10–15 nm, surface 88 m{sup 2} g{sup −1}) functionalized with single strand DNA (ss-DNA). The presence of MWCNTs in blood was assessed by Raman spectroscopy, while in liver histological examination and confocal microscopy were used. It was found that ss-DNA-MWCNTs induce oxidative stress in plasma and liver, with the return of the tested parameters to normal values, 6 h after ip injection of nanotubes, with the exception of reduced glutathione in plasma. The inflammatory cytokines (TNF-α, IL-1β) had a similar pattern of evolution. We also assessed the level of ERK1/2 and the phosphorylation of p65 subunit of NF-kB in liver that had a transient increase and returned to normal at the end of the tested period. Our results demonstrate that ss-DNA-MWCNTs produce oxidative stress and inflammation, but with a transient pattern. Given the fact that antioxidants modify the profile not only for oxidative stress, but also of inflammation, the dynamics of these alterations may be of practical importance for future protective strategies. -- Highlights: ► ss-DNA-MWCNTs ip administration induce oxidative stress in plasma and liver. ► ss-DNA-MWCNTs ip administration determine liver inflammation. ► ERK1/2 and p65 phosphorylated NF-KB increase in liver after MWCNTs ip injection. ► All the alterations, except plasma GSH, return to normal within 6 days.« less

Thermal shock behavior of W-ZrC/Sc2O3 composites under two different transient events by electron and laser irradiation

NASA Astrophysics Data System (ADS)

Chen, Hong-Yu; Luo, Lai-Ma; Zan, Xiang; Xu, Qiu; Tokunaga, Kazutoshi; Liu, Jia-Qin; Zhu, Xiao-Yong; Cheng, Ji-Gui; Wu, Yu-Cheng

2018-02-01

The transient thermal shock behaviors of W-ZrC/Sc2O3 composites with different ZrC contents were evaluated using transient thermal shock test by electron and laser beams. The effects of different ZrC doping contents on the surface morphology and thermal shock resistance of W-ZrC/Sc2O3 composites were then investigated. Similarity and difference between effects of electron and laser beam transient heat loading were also discussed in this study. Repeated heat loading resulted in thermal fatigue of the irradiated W-ZrC/Sc2O3 samples by thermal stress, leading to the rough surface morphologies with cracks. After different transient thermal tests, significant surface roughening, cracks, surface melting, and droplet ejection occurred. W-2vol.%Sc2O3 sample has superior thermal properties and greater resistance to surface modifications under transient thermal shock, and with the increasing ZrC content in W alloys, thermal shock resistance of W-Zr/Sc2O3 sample tends to be unsatisfied.

Transient global amnesia—a hippocampal phenomenon?

PubMed Central

Ponsford, J L; Donnan, G A

1980-01-01

A case of transient global amnesia of clear vascular aetiology is described. Results of neuropsychological testing carried out during the attack clarify the nature of the memory disorder and suggest that the critical region of ischaemia is the medial temporal area around the hippocampus. Follow-up testing suggests that no lasting memory impairment resulted. PMID:7373328

Circular swimming in mice after exposure to a high magnetic field.

PubMed

Houpt, Thomas A; Houpt, Charles E

2010-06-16

There is increasing evidence that exposure to high magnetic fields of 4T and above perturbs the vestibular system of rodents and humans. Performance in a swim test is a sensitive test of vestibular function. In order to determine the effect of magnet field exposure on swimming in mice, mice were exposed for 30 min within a 14.1T superconducting magnet and then tested at different times after exposure in a 2-min swim test. As previously observed in open field tests, mice swam in tight counter-clockwise circles when tested immediately after magnet exposure. The counter-clockwise orientation persisted throughout the 2-min swim test. The tendency to circle was transient, because no significant circling was observed when mice were tested at 3 min or later after magnet exposure. However, mice did show a decrease in total distance swum when tested between 3 and 40 min after magnet exposure. The decrease in swimming distance was accompanied by a pronounced postural change involving a counter-clockwise twist of the pelvis and hindlimbs that was particularly severe in the first 15s of the swim test. Finally, no persistent difference from sham-exposed mice was seen in the swimming of magnet-exposed mice when tested 60 min, 24h, or 96 h after magnet exposure. This suggests that there is no long-lasting effect of magnet exposure on the ability of mice to orient or swim. The transient deficits in swimming and posture seen shortly after magnet exposure are consistent with an acute perturbation of the vestibular system by the high magnetic field. (c) 2010 Elsevier Inc. All rights reserved.

Molecular analysis of the ependymin gene and functional test of its promoter region by transient expression in Brachydanio rerio.

PubMed

Rinder, H; Bayer, T A; Gertzen, E M; Hoffmann, W

1992-01-01

Ependymins are secretory products of meningeal cells and represent the predominant glycoproteins in the cerebrospinal fluid from various orders of teleost fish. In the zebrafish, their expression starts between 48 and 72 h post-fertilization. Generally, they share characteristics with proteins involved in cell-contact phenomena. Here, we characterize the ependymin gene from Brachydanio rerio and its flanking regions. The sequence was obtained from clones generated using the polymerase chain reaction (PCR), including a variation of an "anchored" PCR. Also, clones from a conventional phage library were analyzed. We found that the transcribed portion is arranged in six exons. Transient expression of an ependymin-promoter-lacZ gene fusion in zebrafish embryos revealed that the 2.0-kb upstream regulatory region used is sufficient to direct the ependymin-specific correct temporal and spatial expression pattern of the lacZ reporter gene.

A de-noising method using the improved wavelet threshold function based on noise variance estimation

NASA Astrophysics Data System (ADS)

Liu, Hui; Wang, Weida; Xiang, Changle; Han, Lijin; Nie, Haizhao

2018-01-01

The precise and efficient noise variance estimation is very important for the processing of all kinds of signals while using the wavelet transform to analyze signals and extract signal features. In view of the problem that the accuracy of traditional noise variance estimation is greatly affected by the fluctuation of noise values, this study puts forward the strategy of using the two-state Gaussian mixture model to classify the high-frequency wavelet coefficients in the minimum scale, which takes both the efficiency and accuracy into account. According to the noise variance estimation, a novel improved wavelet threshold function is proposed by combining the advantages of hard and soft threshold functions, and on the basis of the noise variance estimation algorithm and the improved wavelet threshold function, the research puts forth a novel wavelet threshold de-noising method. The method is tested and validated using random signals and bench test data of an electro-mechanical transmission system. The test results indicate that the wavelet threshold de-noising method based on the noise variance estimation shows preferable performance in processing the testing signals of the electro-mechanical transmission system: it can effectively eliminate the interference of transient signals including voltage, current, and oil pressure and maintain the dynamic characteristics of the signals favorably.

Impact and Penetration of Thin Aluminum 2024 Flat Panels at Oblique Angles of Incidence

NASA Technical Reports Server (NTRS)

Ruggeri, Charles R.; Revilock, Duane M.; Pereira, J. Michael; Emmerling, William; Queitzsch, Gilbert K., Jr.

2015-01-01

The U.S. Federal Aviation Administration (FAA) and the National Aeronautics and Space Administration (NASA) are actively involved in improving the predictive capabilities of transient finite element computational methods for application to safety issues involving unintended impacts on aircraft and aircraft engine structures. One aspect of this work involves the development of an improved deformation and failure model for metallic materials, known as the Tabulated Johnson-Cook model, or MAT224, which has been implemented in the LS-DYNA commercial transient finite element analysis code (LSTC Corp., Livermore, CA) (Ref. 1). In this model the yield stress is a function of strain, strain rate and temperature and the plastic failure strain is a function of the state of stress, temperature and strain rate. The failure criterion is based on the accumulation of plastic strain in an element. The model also incorporates a regularization scheme to account for the dependency of plastic failure strain on mesh size. For a given material the model requires a significant amount of testing to determine the yield stress and failure strain as a function of the three-dimensional state of stress, strain rate and temperature. In addition, experiments are required to validate the model. Currently the model has been developed for Aluminum 2024 and validated against a series of ballistic impact tests on flat plates of various thicknesses (Refs. 1 to 3). Full development of the model for Titanium 6Al-4V is being completed, and mechanical testing for Inconel 718 has begun. The validation testing for the models involves ballistic impact tests using cylindrical projectiles impacting flat plates at a normal incidence (Ref. 2). By varying the thickness of the plates, different stress states and resulting failure modes are induced, providing a range of conditions over which the model can be validated. The objective of the study reported here was to provide experimental data to evaluate the model under more extreme conditions, using a projectile with a more complex shape and sharp contacts, impacting flat panels at oblique angles of incidence.

Mixing and transient interface condensation of a liquid hydrogen tank

NASA Technical Reports Server (NTRS)

Lin, C. S.; Hasan, M. M.; Nyland, T. W.

1993-01-01

Experiments were conducted to investigate the effect of axial jet-induced mixing on the pressure reduction of a thermally stratified liquid hydrogen tank. The tank was nearly cylindrical, having a volume of about 0.144 cu m with 0.559 m in diameter and 0.711 m length. A mixer/pump unit, which had a jet nozzle outlet of 0.0221 m in diameter was located 0.178 m from the tank bottom and was installed inside the tank to generate the axial jet mixing and tank fluid circulation. Mixing tests began with the tank pressures at which the thermal stratification results in 4.9-6.2 K liquid subcooling. The mixing time and transient vapor condensation rate at the liquid-vapor interface are determined. Two mixing time correlations, based on the thermal equilibrium and pressure equilibrium, are developed and expressed as functions of system and buoyancy parameters. The limited liquid hydrogen data of the present study shows that the modified steady state condensation rate correlation may be used to predict the transient condensation rate in a mixing process if the instantaneous values of jet sub cooling and turbulence intensity at the interface are employed.

Investigation of natural circulation instability and transients in passively safe novel modular reactor

NASA Astrophysics Data System (ADS)

Shi, Shanbin

The Purdue Novel Modular Reactor (NMR) is a new type small modular reactor (SMR) that belongs to the design of boiling water reactor (BWR). Specifically, the NMR is one third the height and area of a conventional BWR reactor pressure vessel (RPV) with an electric output of 50 MWe. The fuel cycle length of the NMR-50 is extended up to 10 years due to optimized neutronics design. The NMR-50 is designed with double passive engineering safety system. However, natural circulation BWRs (NCBWR) could experience certain operational difficulties due to flow instabilities that occur at low pressure and low power conditions. Static instabilities (i.e. flow excursion (Ledinegg) instability and flow pattern transition instability) and dynamic instabilities (i.e. density wave instability and flashing/condensation instability) pose a significant challenge in two-phase natural circulation systems. In order to experimentally study the natural circulation flow instability, a proper scaling methodology is needed to build a reduced-size test facility. The scaling analysis of the NMR uses a three-level scaling method, which was developed and applied for the design of the Purdue Multi-dimensional Integral Test Assembly (PUMA). Scaling criteria is derived from dimensionless field equations and constitutive equations. The scaling process is validated by the RELAP5 analysis for both steady state and startup transients. A new well-scaled natural circulation test facility is designed and constructed based on the scaling analysis of the NMR-50. The experimental facility is installed with different equipment to measure various thermal-hydraulic parameters such as pressure, temperature, mass flow rate and void fraction. Characterization tests are performed before the startup transient tests and quasi-steady tests to determine the loop flow resistance. The controlling system and data acquisition system are programmed with LabVIEW to realize the real-time control and data storage. The thermal-hydraulic and nuclear coupled startup transients are performed to investigate the flow instabilities at low pressure and low power conditions. Two different power ramps are chosen to study the effect of power density on the flow instability. The experimental startup transient tests show the existence of three different flow instability mechanisms during the low pressure startup transients, i.e., flashing instability, condensation induced instability, and density wave oscillations. Flashing instability in the chimney section of the test loop and density wave oscillation are the main flow instabilities observed when the system pressure is below 0.5 MPa. They show completely different type of oscillations, i.e., intermittent oscillation and sinusoidal oscillation, in void fraction profile during the startup transients. In order to perform nuclear-coupled startup transients with void reactivity feedback, the Point Kinetics model is utilized to calculate the transient power during the startup transients. In addition, the differences between the electric resistance heaters and typical fuel element are taken into account. The reactor power calculated shows some oscillations due to flashing instability during the transients. However, the void reactivity feedback does not have significant influence on the flow instability during the startup procedure for the NMR-50. Further investigation of very small power ramp on the startup transients is carried out for the thermal-hydraulic startup transients. It is found that very small power density can eliminate the flashing oscillation in the single phase natural circulation and stabilize the flow oscillations in the phase of net vapor generation. Furthermore, initially pressurized startup procedure is investigated to eliminate the main flow instabilities. The results show that the pressurized startup procedure can suppress the flashing instability at low pressure and low power conditions. In order to have a deep understanding of natural circulation flow instability, the quasi-steady tests are performed using the test facility installed with preheater and subcooler. The effects of system pressure, core inlet subcooling, core power density, inlet flow resistance coefficient, and void reactivity feedback are investigated in the quasi-steady state tests. The stability boundaries are determined between unstable and stable flow conditions in the dimensionless stability plane of inlet subcooling number and Zuber number. In order to predict the stability boundary theoretically, linear stability analysis in the frequency domain is performed at four sections of the loop. The flashing in the chimney is considered as an axially uniform heat source. The dimensionless characteristic equation of the pressure drop perturbation is obtained by considering the void fraction effect and outlet flow resistance in the chimney section. The flashing boundary shows some discrepancies with previous experimental data from the quasi-steady state tests. In the future, thermal non-equilibrium is recommended to improve the accuracy of flashing instability boundary.

Contact thermal shock test of ceramics

NASA Technical Reports Server (NTRS)

Rogers, W. P.; Emery, A. F.

1992-01-01

A novel quantitative thermal shock test of ceramics is described. The technique employs contact between a metal-cooling rod and hot disk-shaped specimen. In contrast with traditional techniques, the well-defined thermal boundary condition allows for accurate analyses of heat transfer, stress, and fracture. Uniform equibiaxial tensile stresses are induced in the center of the test specimen. Transient specimen temperature and acoustic emission are monitored continuously during the thermal stress cycle. The technique is demonstrated with soda-lime glass specimens. Experimental results are compared with theoretical predictions based on a finite-element method thermal stress analysis combined with a statistical model of fracture. Material strength parameters are determined using concentric ring flexure tests. Good agreement is found between experimental results and theoretical predictions of failure probability as a function of time and initial specimen temperature.

Fiber-optic sensor demonstrator (FSD) preliminary test results on PROBA-2

NASA Astrophysics Data System (ADS)

Kruzelecky, Roman V.; Zou, Jing; Haddad, Emile; Jamroz, Wes; Ricci, Francesco; Edwards, Eric; McKenzie, Iain; Vuilleumier, Pierrik

2017-11-01

Fiber Sensor Demonstrator (FSD) developed by MPB Communications (MPBC) is the first demonstration of a full fiber-optic sensor network in the space environment on a satellite. FSD has been launched on ESA's Proba-2 satellite in November 2009. FSD contains twelve temperature sensors to measure the temperature at different locations in the satellite, and one High-Temperature sensor to measure the transient high temperature in the thruster, as well as one pressure sensor to measure the xenon tank pressure. First set of on-orbit test data were obtained in January 2010. The FSD unit successfully established the communication with Proba-2. The temperature of FSD unit was also acquired through a AD590 sensor inside the unit. The measurements of all the optical fiber sensor lines will be evaluated after the testing results obtained. The FSD contains twelve specially-packaged FBG temperature sensors to measure the temperature at different locations in the propulsion system and the spacecraft over the range of -60°C to +120°C. A high-temperature sensor is provided to measure the transient temperature response of the thruster to beyond 350°C. There is also an innovative P/T sensor that provides both temperature and pressure measurements of the Xe propellant tank. The preliminary data of on-orbit functional testing and temperature measurements are provided mainly in Section 6.

Tetanic Ca2+ transient differences between slow- and fast-twitch mouse skeletal muscle fibres: a comprehensive experimental approach.

PubMed

Calderón, Juan C; Bolaños, Pura; Caputo, Carlo

2014-12-01

One hundred and eighty six enzymatically dissociated murine muscle fibres were loaded with Mag-Fluo-4 AM, and adhered to laminin, to evaluate the effect of modulating cytosolic Ca(2+) buffers and sarcoendoplasmic reticulum Ca(2+) ATPase (SERCA), mitochondria, and Na(+)/Ca(2+) exchanger (NCX) on the differential tetanic Ca(2+) transient kinetics found in different fibre types. Tetanic Ca(2+) transients were classified as morphology type I (MT-I) or type II (MT-II) according to their shape. The first peak of the MT-I (n = 25) and MT-II (n = 23) tetanic Ca(2+) transients had an amplitude (∆F/F) of 0.41 ± 0.03 and 0.83 ± 0.05 and a rise time (ms) of 1.35 and 0.98, respectively. MT-I signals had a time constant of decay (τ1, ms) of 75.9 ± 4.2 while MT-II transients showed a double exponential decay with time constants of decay (τ1 and τ2, ms) of 18.3 ± 1.4 and 742.2 ± 130.3. Sarcoendoplasmic reticulum Ca(2+) ATPase inhibition demonstrated that the decay phase of the tetanic transients mostly rely on SERCA function. Adding Ca(2+) chelators in the AM form to MT-I fibres changed the morphology of the initial five peaks to a MT-II one, modifying the decay phase of the signal in a dose-dependent manner. Mitochondria and NCX function have a minor role in explaining differences in tetanic Ca(2+) transients among fibre types but still help in removing Ca(2+) from the cytosol in both MT-I and MT-II fibres. Cytoplasmic Ca(2+) buffering capacity and SERCA function explain most of the different kinetics found in tetanic Ca(2+) transients from different fibre types, but mitochondria and NCX have a measurable role in shaping tetanic Ca(2+) responses in both slow and fast-twitch muscle fibre types. We provided experimental evidence on the mechanisms that help understand the kinetics of tetanic Ca(2+) transients themselves and explain kinetic differences found among fibre types.

Capturing real-life forgetting in transient epileptic amnesia via an incidental memory test.

PubMed

Hoefeijzers, Serge; Zeman, Adam; Della Sala, Sergio; Dewar, Michaela

2017-12-13

Transient epileptic amnesia (TEA) is an epileptic syndrome characterized by recurrent, brief episodes of amnesia. Patients with TEA often complain of interictal (between attacks) retention deficits, characterised by an 'evaporation' of memories for recent events over days to weeks. Clinical tests of anterograde memory often fail to corroborate these complaints as TEA patients commonly perform within the normal range after the standard 10-30-min delay period. Modified laboratory tests that include a 1-3 week delay period frequently reveal clear evidence of 'accelerated long-term forgetting' (ALF). However, they are not used routinely and lack ecological validity. In the present study we examined whether 'real-life' ALF can be captured via a controlled incidental memory test in TEA patients. To this end, the experimenter told 27 TEA patients and 32 controls a well-rehearsed amusing story, apparently as a way of making light conversation before starting a set of research experiments. Without prior warning, the experimenter subsequently probed the participants' memory of this story via tests of free recall and forced choice recognition after 30 min or 1 week. After 30 min retention was comparable in TEA patients and controls. After 1 week TEA patients retained significantly less story material than controls, and significant ALF was revealed in the TEA patients in the recognition test. Our data show that ALF in a 'real-life' situation can occur even when standard memory tests indicate normal memory function. Moreover, our data suggest that incidental memory tests can capture real-life ALF, and that forced-choice recognition tests might be more sensitive than free recall tests for the detection of real-life ALF. Copyright © 2017 Elsevier Ltd. All rights reserved.

Transient severe left ventricular dysfunction following percutaneous patent ductus arteriosus closure in an adult with bicuspid aortic valve: A case report

PubMed Central

HWANG, HUI-JEONG; YOON, KYUNG LIM; SOHN, IL SUK

2016-01-01

The present study reported the case of a 60-year-old female with patent ductus arteriosus (PDA) and a bicuspid aortic valve, who presented with transient severe left ventricular (LV) dysfunction following percutaneous closure of PDA, as identified by speckle tracking analysis. Transient LV dysfunction following PDA closure has previously been reported; however, severe LV dysfunction is rare. In the present case, the combination of a large PDA size, large amount of shunting, LV remodeling and bicuspid aortic valve may have induced serious deterioration of LV function following PDA closure. Furthermore, speckle-tracking echocardiography may be useful in the estimation of functional alterations in the myocardium of the LV following PDA closure. The observations detailed in the present study may improve the understanding of the pathophysiology and myocardial patterns of transient left ventricular dysfunction following PDA closure in adult humans. PMID:26998021

Transient severe left ventricular dysfunction following percutaneous patent ductus arteriosus closure in an adult with bicuspid aortic valve: A case report.

PubMed

Hwang, Hui-Jeong; Yoon, Kyung Lim; Sohn, Il Suk

2016-03-01

The present study reported the case of a 60-year-old female with patent ductus arteriosus (PDA) and a bicuspid aortic valve, who presented with transient severe left ventricular (LV) dysfunction following percutaneous closure of PDA, as identified by speckle tracking analysis. Transient LV dysfunction following PDA closure has previously been reported; however, severe LV dysfunction is rare. In the present case, the combination of a large PDA size, large amount of shunting, LV remodeling and bicuspid aortic valve may have induced serious deterioration of LV function following PDA closure. Furthermore, speckle-tracking echocardiography may be useful in the estimation of functional alterations in the myocardium of the LV following PDA closure. The observations detailed in the present study may improve the understanding of the pathophysiology and myocardial patterns of transient left ventricular dysfunction following PDA closure in adult humans.

Subscale Test Methods for Combustion Devices

NASA Technical Reports Server (NTRS)

Anderson, W. E.; Sisco, J. C.; Long, M. R.; Sung, I.-K.

2005-01-01

Stated goals for long-life LRE s have been between 100 and 500 cycles: 1) Inherent technical difficulty of accurately defining the transient and steady state thermochemical environments and structural response (strain); 2) Limited statistical basis on failure mechanisms and effects of design and operational variability; and 3) Very high test costs and budget-driven need to protect test hardware (aversion to test-to-failure). Ambitious goals will require development of new databases: a) Advanced materials, e.g., tailored composites with virtually unlimited property variations; b) Innovative functional designs to exploit full capabilities of advanced materials; and c) Different cycles/operations. Subscale testing is one way to address technical and budget challenges: 1) Prototype subscale combustors exposed to controlled simulated conditions; 2) Complementary to conventional laboratory specimen database development; 3) Instrumented with sensors to measure thermostructural response; and 4) Coupled with analysis

Otoacoustic emission testing in Ghanaian children with sickle-cell disease.

PubMed

Kegele, Josua; Hurth, Helene; Lackner, Peter; Enimil, Anthony; Sylverkin, Justice; Ansong, Daniel; Nkyi, Clara; Bonsu, Benedicta; Agbenyega, Tsiri; Schartinger, Volker H; Schmutzhard, Erich; Zorowka, Patrick; Kremsner, Peter; Schmutzhard, Joachim

2015-09-01

To evaluate hearing loss in children as a complication of sickle-cell disease. In Kumasi, Ghana, 35 children with SCD aged 6 months to 10 years underwent transient-evoked otoacoustic emissions testing (TEOAE) to investigate the function of the inner ear. Healthy Ghanaian children recruited in school and kindergarten served as controls. One of 35 children with SCD and 13 of 115 control children failed the otoacoustic emissions testing. This difference between the control group and the children with SCD was not statistically significant. Early hearing impairment does not regularly occur in sickle-cell disease, and in children, it is not a likely cause of delayed or impaired language development. © 2015 John Wiley & Sons Ltd.

Soft interactions and volume exclusion by polymeric crowders can stabilize or destabilize transient structure in disordered proteins depending on polymer concentration.

PubMed

Rusinga, Farai I; Weis, David D

2017-08-01

The effects of macromolecular crowding on the transient structure of intrinsically disordered proteins is not well-understood. Crowding by biological molecules inside cells could modulate transient structure and alter IDP function. Volume exclusion theory and observations of structured proteins suggest that IDP transient structure would be stabilized by macromolecular crowding. Amide hydrogen exchange (HX) of IDPs in highly concentrated polymer solutions would provide valuable insights into IDP transient structure under crowded conditions. Here, we have used mass spectrometry to measure HX by a transiently helical random coil domain of the activator of thyroid and retinoid receptor (ACTR) in solutions containing 300 g L -1 and 400 g L -1 of Ficoll, a synthetic polysaccharide, using a recently-developed strong cation exchange-based cleanup method [Rusinga, et al., Anal Chem 2017;89:1275-1282]. Transiently helical regions of ACTR exchanged faster in 300 g L -1 Ficoll than in dilute buffer. In contrast, one transient helix exchanged more slowly in 400 g L -1 Ficoll. Nonspecific interactions destabilize ACTR helicity in 300 g L -1 Ficoll because ACTR engages with the Ficoll polymer mesh. In contrast, 400 g L -1 Ficoll is a semi-dilute solution where ACTR cannot engage the Ficoll mesh. At this higher concentration, volume exclusion stabilizes ACTR helicity because ACTR is compacted in interstitial spaces between Ficoll molecules. Our results suggest that the interplay between nonspecific interactions and volume exclusion in different cellular compartments could modulate IDP function by altering the stability of IDP transient structures. Proteins 2017; 85:1468-1479. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Calculating transient rates from surveys

NASA Astrophysics Data System (ADS)

Carbone, D.; van der Horst, A. J.; Wijers, R. A. M. J.; Rowlinson, A.

2017-03-01

We have developed a method to determine the transient surface density and transient rate for any given survey, using Monte Carlo simulations. This method allows us to determine the transient rate as a function of both the flux and the duration of the transients in the whole flux-duration plane rather than one or a few points as currently available methods do. It is applicable to every survey strategy that is monitoring the same part of the sky, regardless the instrument or wavelength of the survey, or the target sources. We have simulated both top-hat and Fast Rise Exponential Decay light curves, highlighting how the shape of the light curve might affect the detectability of transients. Another application for this method is to estimate the number of transients of a given kind that are expected to be detected by a survey, provided that their rate is known.

Preflight transient dynamic analyses of B-52 aircraft carrying Space Shuttle solid rocket booster drop-test vehicle

NASA Technical Reports Server (NTRS)

Ko, W. L.; Schuster, L. S.

1984-01-01

This paper concerns the transient dynamic analysis of the B-52 aircraft carrying the Space Shuttle solid rocket booster drop test vehicle (SRB/DTV). The NASA structural analysis (NASTRAN) finite element computer program was used in the analysis. The B-52 operating conditions considered for analysis were (1) landing and (2) braking on aborted takeoff runs. The transient loads for the B-52 pylon front and rear hooks were calculated. The results can be used to establish the safe maneuver envelopes for the B-52 carrying the SRB/DTV in landings and brakings.

Pre-flight transient dynamic analysis of B-52 carrying Space Shuttle solid rocket booster drop-test vehicle

NASA Technical Reports Server (NTRS)

Ko, W. L.; Schuster, L. S.

1983-01-01

This paper concerns the transient dynamic analysis of the B-52 aircraft carrying the Space Shuttle solid-rocket booster drop-test vehicle (SRB/DTV). The NASA structural analysis (NASTRAN) finite-element computer program was used in the analysis. The B-52 operating conditions considered for analysis were (1) landing and (2) braking on aborted takeoff runs. The transient loads for the B-52 pylon front and rear hooks were calculated. The results can be used to establish the safe maneuver envelopes for the B-52 carrying the SRB/DTV in landings and brakings.

40 CFR 1048.510 - What transient duty cycles apply for laboratory testing?

Code of Federal Regulations, 2013 CFR

2013-07-01

... model year, measure emissions by testing the engine on a dynamometer with the duty cycle described in Appendix II to determine whether it meets the transient emission standards in § 1048.101(a). (b) Calculate cycle statistics and compare with the established criteria as specified in 40 CFR 1065.514 to confirm...

40 CFR 1048.510 - What transient duty cycles apply for laboratory testing?

Code of Federal Regulations, 2011 CFR

2011-07-01

... model year, measure emissions by testing the engine on a dynamometer with the duty cycle described in Appendix II to determine whether it meets the transient emission standards in § 1048.101(a). (b) Calculate cycle statistics and compare with the established criteria as specified in 40 CFR 1065.514 to confirm...

40 CFR 1048.510 - What transient duty cycles apply for laboratory testing?

Code of Federal Regulations, 2014 CFR

2014-07-01

... model year, measure emissions by testing the engine on a dynamometer with the duty cycle described in Appendix II to determine whether it meets the transient emission standards in § 1048.101(a). (b) Calculate cycle statistics and compare with the established criteria as specified in 40 CFR 1065.514 to confirm...

40 CFR 1048.510 - What transient duty cycles apply for laboratory testing?

Code of Federal Regulations, 2012 CFR

2012-07-01

... model year, measure emissions by testing the engine on a dynamometer with the duty cycle described in Appendix II to determine whether it meets the transient emission standards in § 1048.101(a). (b) Calculate cycle statistics and compare with the established criteria as specified in 40 CFR 1065.514 to confirm...

CASE-REPORT Dysregulation of gene expression in a patient with depressive disorder after transient ischemic attack confirmed by a neurophysiological neuromarker.

PubMed

Trystuła, M; Żychowska, M; Wilk-Frańczuk, M; Kropotov, J D; Pąchalska, M

2017-02-16

The aim of this study was to evaluate dysregulation of gene expression associated with the cellular stress response in a patient with a post-"warning stroke" depressive disorder confirmed by the presence of a neurophysiological neuromarker through the use of quantitative EEG and event-related potentials. The patient was tested for seven genes associated with the stress reaction: HSPA1A, HSPB1, IL6, IL10, CRP, and HSF-1 along with NF-κB, compared to gene expression in health controls. A 54-year-old patient with a past history of schizophrenia (at the age of 20), and of transient ischemic attack (at the age of 53) and depressive disorder confirmed by functional, cognitive, emotional, and affectional diagnostics underwent additional testing for expression of the genes associated with stress response. The expression of genes coding for heat shock protein (HSPA1A, HSPB1), interleukins (IL6, IL10), and C-reactive protein was tested along with factors that regulate their expression. The results of the tests conducted on this patient were compared with 42 healthy control subjects. Diagnostic testing revealed upregulation in expression of these genes, presenting as increased expression of the target genes and of the regulatory genes. A post-"warning stroke" depressive disorder appears to be associated with overexpression of the genes coding for HSP and interleukins. Further research on larger groups of people may provide grounds for treatment modification.

The Volumetric Rate of Calcium-rich Transients in the Local Universe

NASA Astrophysics Data System (ADS)

Frohmaier, Chris; Sullivan, Mark; Maguire, Kate; Nugent, Peter

2018-05-01

We present a measurement of the volumetric rate of “calcium-rich” optical transients in the local universe, using a sample of three events from the Palomar Transient Factory (PTF). This measurement builds on a detailed study of the PTF transient detection efficiencies and uses a Monte Carlo simulation of the PTF survey. We measure the volumetric rate of calcium-rich transients to be higher than previous estimates: {1.21}-0.39+1.13 × {10}-5 events yr‑1 Mpc‑3. This is equivalent to 33%–94% of the local volumetric Type Ia supernova rate. This calcium-rich transient rate is sufficient to reproduce the observed calcium abundances in galaxy clusters, assuming an asymptotic calcium yield per calcium-rich event of ∼0.05 {M}ȯ . We also study the PTF detection efficiency of these transients as a function of position within their candidate host galaxies. We confirm as a real physical effect previous results that suggest that calcium-rich transients prefer large physical offsets from their host galaxies.

Analog-digital simulation of transient-induced logic errors and upset susceptibility of an advanced control system

NASA Technical Reports Server (NTRS)

Carreno, Victor A.; Choi, G.; Iyer, R. K.

1990-01-01

A simulation study is described which predicts the susceptibility of an advanced control system to electrical transients resulting in logic errors, latched errors, error propagation, and digital upset. The system is based on a custom-designed microprocessor and it incorporates fault-tolerant techniques. The system under test and the method to perform the transient injection experiment are described. Results for 2100 transient injections are analyzed and classified according to charge level, type of error, and location of injection.

Laser-induced transient grating setup with continuously tunable period

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

Vega-Flick, A.; Applied Physics Department, CINVESTAV-Unidad Mérida, Carretera Antigua a Progreso Km 6, Cordemex, Mérida, Yucatán 97310 Mexico; Eliason, J. K.

2015-12-15

We present a modification of the laser-induced transient grating setup enabling continuous tuning of the transient grating period. The fine control of the period is accomplished by varying the angle of the diffraction grating used to split excitation and probe beams. The setup has been tested by measuring dispersion of bulk and surface acoustic waves in both transmission and reflection geometries. The presented modification is fully compatible with optical heterodyne detection and can be easily implemented in any transient grating setup.

Liver fibrosis diagnosis by blood test and elastography in chronic hepatitis C: agreement or combination?

PubMed

Calès, P; Boursier, J; Lebigot, J; de Ledinghen, V; Aubé, C; Hubert, I; Oberti, F

2017-04-01

In chronic hepatitis C, the European Association for the Study of the Liver and the Asociacion Latinoamericana para el Estudio del Higado recommend performing transient elastography plus a blood test to diagnose significant fibrosis; test concordance confirms the diagnosis. To validate this rule and improve it by combining a blood test, FibroMeter (virus second generation, Echosens, Paris, France) and transient elastography (constitutive tests) into a single combined test, as suggested by the American Association for the Study of Liver Diseases and the Infectious Diseases Society of America. A total of 1199 patients were included in an exploratory set (HCV, n = 679) or in two validation sets (HCV ± HIV, HBV, n = 520). Accuracy was mainly evaluated by correct diagnosis rate for severe fibrosis (pathological Metavir F ≥ 3, primary outcome) by classical test scores or a fibrosis classification, reflecting Metavir staging, as a function of test concordance. Score accuracy: there were no significant differences between the blood test (75.7%), elastography (79.1%) and the combined test (79.4%) (P = 0.066); the score accuracy of each test was significantly (P < 0.001) decreased in discordant vs. concordant tests. Classification accuracy: combined test accuracy (91.7%) was significantly (P < 0.001) increased vs. the blood test (84.1%) and elastography (88.2%); accuracy of each constitutive test was significantly (P < 0.001) decreased in discordant vs. concordant tests but not with combined test: 89.0 vs. 92.7% (P = 0.118). Multivariate analysis for accuracy showed an interaction between concordance and fibrosis level: in the 1% of patients with full classification discordance and severe fibrosis, non-invasive tests were unreliable. The advantage of combined test classification was confirmed in the validation sets. The concordance recommendation is validated. A combined test, expressed in classification instead of score, improves this rule and validates the recommendation of a combined test, avoiding 99% of biopsies, and offering precise staging. © 2017 John Wiley & Sons Ltd.

Impaired mitochondria and intracellular calcium transients in the salivary glands of obese rats.

PubMed

Ittichaicharoen, Jitjiroj; Apaijai, Nattayaporn; Tanajak, Pongpan; Sa-Nguanmoo, Piangkwan; Chattipakorn, Nipon; Chattipakorn, Siriporn C

2017-04-01

Long-term consumption of a high-fat diet (HFD) causes not only obese-insulin resistance, but is also associated with mitochondrial dysfunction in several organs. However, the effect of obese-insulin resistance on salivary glands has not been investigated. We hypothesized that obese-insulin resistance induced by HFD impaired salivary gland function by reducing salivation, increasing inflammation, and fibrosis, as well as impairing mitochondrial function and calcium transient signaling. Male Wistar rats (200-220 g) were fed either a ND or an HFD (n = 8/group) for 16 weeks. At the end of week 16, salivary flow rates, metabolic parameters, and plasma oxidative stress were determined. Rats were then sacrificed and submandibular glands were removed to determine inflammation, fibrosis, apoptosis, mitochondrial function and dynamics, and intracellular calcium transient signaling. Long-term consumption of an HFD caused obese-insulin resistance and increased oxidative stress, fibrosis, inflammation, and apoptosis in the salivary glands. In addition, impaired mitochondrial function, as indicated by increased mitochondrial reactive oxygen species, mitochondrial membrane depolarization, and mitochondrial swelling in salivary glands and impaired intracellular calcium regulation, as indicated by a reduced intracellular calcium transient rising rate, decay rates, and amplitude of salivary acinar cells, were observed in HFD-fed rats. However, salivary flow rate and level of aquaporin 5 protein were not different between both groups. Although HFD consumption did not affect salivation, it caused obese-insulin resistance, leading to pathophysiological alteration of salivary glands, including impaired intracellular calcium transients, increased oxidative stress and inflammation, and salivary mitochondrial dysfunction.

Integrin α1β1 participates in Chondrocyte Transduction of Osmotic Stress.

PubMed Central

Jablonski, Christina L.; Ferguson, Samuel; Pozzi, Ambra; Clark, Andrea L.

2014-01-01

Background/purpose: The goal of this study was to determine the role of the collagen binding receptor integrin α1β1 in regulating osmotically induced [Ca2+]i transients in chondrocytes. Methods: The [Ca2+]i transient response of chondrocytes to osmotic stress was measured using real-time confocal microscopy. Chondrocytes from wildtype and integrin α1-null mice were imaged ex vivo (in the cartilage of intact murine femora) and in vitro (isolated from the matrix, attached to glass coverslips). Immunocytochemistry was performed to detect the presence of the osmosensor, transient receptor potential vanilloid-4 (TRPV4), and the agonist GSK1016790A (GSK101) was used to test for its functionality on chondrocytes from wildtype and integrin α1-null mice. Results/interpretation: Deletion of the integrin α1 subunit inhibited the ability of chondrocytes to respond to a hypo-osmotic stress with [Ca2+]i transients ex vivo and in vitro. The percentage of chondrocytes responding ex vivo was smaller than in vitro and of the cells that responded, more single [Ca2+]i transients were observed ex vivo compared to in vitro. Immunocytochemistry confirmed the presence of TRPV4 on wildtype and integrin α1-null chondrocytes, however application of GSK101 revealed that TRPV4 could be activated on wildtype but not integrin α1-null chondrocytes. Integrin α1β1 is a key participant in chondrocyte transduction of a hypo-osmotic stress. Furthermore, the mechanism by which integrin α1β1 influences osmotransduction is independent of matrix binding, but likely dependent on the chondrocyte osmosensor TRPV4. PMID:24495803

Integrin α1β1 participates in chondrocyte transduction of osmotic stress.

PubMed

Jablonski, Christina L; Ferguson, Samuel; Pozzi, Ambra; Clark, Andrea L

2014-02-28

The goal of this study was to determine the role of the collagen binding receptor integrin α1β1 in regulating osmotically induced [Ca(2+)]i transients in chondrocytes. The [Ca(2+)]i transient response of chondrocytes to osmotic stress was measured using real-time confocal microscopy. Chondrocytes from wildtype and integrin α1-null mice were imaged ex vivo (in the cartilage of intact murine femora) and in vitro (isolated from the matrix, attached to glass coverslips). Immunocytochemistry was performed to detect the presence of the osmosensor, transient receptor potential vanilloid-4 (TRPV4), and the agonist GSK1016790A (GSK101) was used to test for its functionality on chondrocytes from wildtype and integrin α1-null mice. Deletion of the integrin α1 subunit inhibited the ability of chondrocytes to respond to a hypo-osmotic stress with [Ca(2+)]i transients ex vivo and in vitro. The percentage of chondrocytes responding ex vivo was smaller than in vitro and of the cells that responded, more single [Ca(2+)]i transients were observed ex vivo compared to in vitro. Immunocytochemistry confirmed the presence of TRPV4 on wildtype and integrin α1-null chondrocytes, however application of GSK101 revealed that TRPV4 could be activated on wildtype but not integrin α1-null chondrocytes. Integrin α1β1 is a key participant in chondrocyte transduction of a hypo-osmotic stress. Furthermore, the mechanism by which integrin α1β1 influences osmotransduction is independent of matrix binding, but likely dependent on the chondrocyte osmosensor TRPV4. Copyright © 2014 Elsevier Inc. All rights reserved.

Separation of variables solution for non-linear radiative cooling

NASA Technical Reports Server (NTRS)

Siegel, Robert

1987-01-01

A separation of variables solution has been obtained for transient radiative cooling of an absorbing-scattering plane layer. The solution applies after an initial transient period required for adjustment of the temperature and scattering source function distributions. The layer emittance, equal to the instantaneous heat loss divided by the fourth power of the instantaneous mean temperature, becomes constant. This emittance is a function of only the optical thickness of the layer and the scattering albedo; its behavior as a function of these quantities is considerably different than for a layer at constant temperature.

Working memory and executive functions in transient global amnesia.

PubMed

Quinette, Peggy; Guillery, Bérengère; Desgranges, Béatrice; de la Sayette, Vincent; Viader, Fausto; Eustache, Francis

2003-09-01

Transient global amnesia (TGA) is usually considered to produce a profound impairment of long-term episodic memory, while at the same time sparing working memory. However, this neuropsychological dissociation has rarely been examined in detail. While a few studies have assessed some components of working memory in TGA, the results that have been obtained are far from conclusive. To clarify this issue, we carried out a comprehensive investigation of working memory in 10 patients during a TGA attack. In the first study, we report the results from three patients examined with a battery of neuropsychological tests designed to assess each of the three subcomponents of Baddeley's model of working memory. In a second study, seven different patients underwent neuropsychological investigations that focused specifically on the central executive system, using a protocol derived from a study by Miyake and colleagues. Our findings showed that subcomponents of working memory, such as the phonological loop and visuo-spatial sketch pad, were spared in TGA patients. Specific executive functions that entailed inhibitory control, dual task performance, updating and shifting mechanisms were also found to be normal. However, we found significantly impaired performance for the Brown-Peterson test, and that TGA patients were significantly impaired in the recollection of their episodic memories. They also made reduced numbers of 'remember' compared with 'know' judgments in the episodic memory test several days after TGA. On the basis of our findings, it would appear that the episodic memory deficit during TGA is not related to elementary aspects of executive functioning. Our data also highlight the nature of the cognitive mechanisms involved in the Brown-Peterson task, which may well depend on long-term memory (such as the process of semantic encoding). Lastly, the selective deficit in recollective episodic memories observed in TGA may be principally related to medial temporal lobe abnormalities that have been reported in this syndrome.

Rapid High-Level Production of Functional HIV Broadly Neutralizing Monoclonal Antibodies in Transient Plant Expression Systems

PubMed Central

Rosenberg, Yvonne; Sack, Markus; Montefiori, David; Forthal, Donald; Mao, Lingjun; -Abanto, Segundo Hernandez; Urban, Lori; Landucci, Gary; Fischer, Rainer; Jiang, Xiaoming

2013-01-01

Passive immunotherapy using anti-HIV broadly neutralizing monoclonal antibodies (mAbs) has shown promise as an HIV treatment, reducing mother-to-child-transmission (MTCT) of simian/human immunodeficiency virus (SHIV) in non-human primates and decreasing viral rebound in patients who ceased receiving anti-viral drugs. In addition, a cocktail of potent mAbs may be useful as mucosal microbicides and provide an effective therapy for post-exposure prophylaxis. However, even highly neutralizing HIV mAbs used today may lose their effectiveness if resistance occurs, requiring the rapid production of new or engineered mAbs on an ongoing basis in order to counteract the viral resistance or the spread of a certain HIV-1 clade in a particular region or patient. Plant-based expression systems are fast, inexpensive and scalable and are becoming increasingly popular for the production of proteins and monoclonal antibodies. In the present study, Agrobacterium-mediated transient transfection of plants, utilizing two species of Nicotiana, have been tested to rapidly produce high levels of an HIV 89.6PΔ140env and several well-studied anti-HIV neutralizing monoclonal antibodies (b12, 2G12, 2F5, 4E10, m43, VRC01) or a single chain antibody construct (m9), for evaluation in cell-based viral inhibition assays. The protein-A purified plant-derived antibodies were intact, efficiently bound HIV envelope, and were equivalent to, or in one case better than, their counterparts produced in mammalian CHO or HEK-293 cells in both neutralization and antibody dependent viral inhibition assays. These data indicate that transient plant-based transient expression systems are very adaptable and could rapidly generate high levels of newly identified functional recombinant HIV neutralizing antibodies when required. In addition, they warrant detailed cost-benefit analysis of prolonged incubation in plants to further increase mAb production. PMID:23533588

Transient well flow in vertically heterogeneous aquifers

NASA Astrophysics Data System (ADS)

Hemker, C. J.

1999-11-01

A solution for the general problem of computing well flow in vertically heterogeneous aquifers is found by an integration of both analytical and numerical techniques. The radial component of flow is treated analytically; the drawdown is a continuous function of the distance to the well. The finite-difference technique is used for the vertical flow component only. The aquifer is discretized in the vertical dimension and the heterogeneous aquifer is considered to be a layered (stratified) formation with a finite number of homogeneous sublayers, where each sublayer may have different properties. The transient part of the differential equation is solved with Stehfest's algorithm, a numerical inversion technique of the Laplace transform. The well is of constant discharge and penetrates one or more of the sublayers. The effect of wellbore storage on early drawdown data is taken into account. In this way drawdowns are found for a finite number of sublayers as a continuous function of radial distance to the well and of time since the pumping started. The model is verified by comparing results with published analytical and numerical solutions for well flow in homogeneous and heterogeneous, confined and unconfined aquifers. Instantaneous and delayed drainage of water from above the water table are considered, combined with the effects of partially penetrating and finite-diameter wells. The model is applied to demonstrate that the transient effects of wellbore storage in unconfined aquifers are less pronounced than previous numerical experiments suggest. Other applications of the presented solution technique are given for partially penetrating wells in heterogeneous formations, including a demonstration of the effect of decreasing specific storage values with depth in an otherwise homogeneous aquifer. The presented solution can be a powerful tool for the analysis of drawdown from pumping tests, because hydraulic properties of layered heterogeneous aquifer systems with partially penetrating wells may be estimated without the need to construct transient numerical models. A computer program based on the hybrid analytical-numerical technique is available from the author.

Recharge and Transient Pore Pressure Propagation in Steep Alpine Mountain Slopes near Poschiavo, Switzerland

NASA Astrophysics Data System (ADS)

de Palézieux, Larissa; Loew, Simon; Zwahlen, Peter

2017-04-01

Within the scope of planning a hydropower pump storage plant in the Poschiavo valley by Lagobianco SA (Repower AG), numerous cored boreholes with depths of 50 to 300 m were drilled at elevations between 963 and 2538 m a.s.l.. In several boreholes Lugeon and transient pressure packer tests were executed at various depths and pore water pressure sensors were properly installed in short monitoring intervals. Several of the boreholes intersect large suspended rock slides showing the characteristic zones of highly fragmented rock mass above a kakirite layer of several tens of meters thickness. This study presents long term transient pressure records from these deep boreholes and relates them to seasonal recharge trends from snow melt and summer rainstorm events. Annual pore pressure amplitudes at depths between 45 and 278 meters, range between 4 and 40 meters. Recharge from snow melt water production is obtained from the Degree-Day Method (Rango and Martinec, 1995), despite a considerable distance between the meteorological station and the location of the boreholes. First estimations of storage properties of the aquifers intersected by the boreholes are determined by fitting a combined snow melt and precipitation pressure function to the observed (delayed and attenuated) pore pressure records using a convolution of the one-dimensional pressure diffusion equation for a semi-infinite aquifer of constant thickness (De Marsily, 1986). Initial hydraulic conductivity values were taken directly from hydraulic tests executed by Lagobianco SA in similar rock types (Figi et al., 2014). For most boreholes this strongly simplified approach yields impressively good fits of the transient pressure records and specific storage/yield values, which vary significantly as a function of sensor depth below the piezometric level. Values range from 1e-6 m-1 to 5e-4 m-1 for confined gneiss-schists aquifers and around 3e-2 m-1 for phreatic aquifers, where pore pressure sensors are located only 20-30 m below the phreatic surface. The obtained values for specific storage and the assumed values for hydraulic conductivity were then verified with a one-dimensional finite element free-surface hydraulic model under steady-state and transient conditions, again fitting the simulated values to the observed pore water pressure records. Boundary conditions were set to constant head at the foot of the column and to infiltration with seepage face review at the top of the column. The results support the observed values for hydraulic conductivity as obtained from the packer tests with low permeabilities in the intact rock mass (K=2e-8 - 3e-10 m/s) and a higher permeability in rock slide masses (around 2e-6 m/s). Furthermore, the values for specific storage found by convolution could be confirmed. Finally, the complex local hydrogeology of an alpine mountain slope with a large suspended rock slide was investigated with a 2D finite element model under steady state and transient conditions. Preliminary results support the theory of a hydraulic barrier at the base of large rock slides with a perched aquifer above and partially unsaturated conditions below the sliding plane. REFERENCES De Marsily, G. (1986), Quantitative Hydrogeology (pp. 198-199). Masson. Figi, D., Brunold, F. & Zwahlen, P. (2014), Felskennwerte - Kennwertebericht, Projekt Lagobianco. Büro für Technische Geologie AG, Sargans. Rango, A., & Martinec, J. (1995), Revisiting the Degree-Day Method for Snowmelt Computations. JAWRA Journal of the American Water Resources Association, 31(4), 657-669.

Preclinical Justification of pbi-shRNA EWS/FLI1 Lipoplex (LPX) Treatment for Ewing's Sarcoma.

PubMed

Rao, Donald D; Jay, Christopher; Wang, Zhaohui; Luo, Xiuquan; Kumar, Padmasini; Eysenbach, Hilary; Ghisoli, Maurizio; Senzer, Neil; Nemunaitis, John

2016-08-01

The EWS/FLI1 fusion gene is well characterized as a driver of Ewing's sarcoma. Bi-shRNA EWS/FLI1 is a functional plasmid DNA construct that transcribes both siRNA and miRNA-like effectors each of which targets the identical type 1 translocation junction region of the EWS/FLI1 transcribed mRNA sequence. Previous preclinical and clinical studies confirm the safety of this RNA interference platform technology and consistently demonstrate designated mRNA and protein target knockdown at greater than 90% efficiency. We initiated development of pbi-shRNA EWS/FLI1 lipoplex (LPX) for the treatment of type 1 Ewing's sarcoma. Clinical-grade plasmid was manufactured and both sequence and activity verified. Target protein and RNA knockdown of 85-92% was demonstrated in vitro in type 1 human Ewing's sarcoma tumor cell lines with the optimal bi-shRNA EWS/FLI1 plasmid. This functional plasmid was placed in a clinically tested, liposomal (LP) delivery vehicle followed by in vivo verification of activity. Type 1 Ewing's sarcoma xenograft modeling confirmed dose related safety and tumor response to pbi-shRNA EWS/FLI1 LPX. Toxicology studies in mini-pigs with doses comparable to the demonstrated in vivo efficacy dose resulted in transient fever, occasional limited hypertension at low- and high-dose assessment and transient liver enzyme elevation at high dose. These results provide the justification to initiate clinical testing.

Preclinical Justification of pbi-shRNA EWS/FLI1 Lipoplex (LPX) Treatment for Ewing's Sarcoma

PubMed Central

Rao, Donald D.; Jay, Christopher; Wang, Zhaohui; Luo, Xiuquan; Kumar, Padmasini; Eysenbach, Hilary; Ghisoli, Maurizio; Senzer, Neil; Nemunaitis, John

2016-01-01

The EWS/FLI1 fusion gene is well characterized as a driver of Ewing's sarcoma. Bi-shRNA EWS/FLI1 is a functional plasmid DNA construct that transcribes both siRNA and miRNA-like effectors each of which targets the identical type 1 translocation junction region of the EWS/FLI1 transcribed mRNA sequence. Previous preclinical and clinical studies confirm the safety of this RNA interference platform technology and consistently demonstrate designated mRNA and protein target knockdown at greater than 90% efficiency. We initiated development of pbi-shRNA EWS/FLI1 lipoplex (LPX) for the treatment of type 1 Ewing's sarcoma. Clinical-grade plasmid was manufactured and both sequence and activity verified. Target protein and RNA knockdown of 85–92% was demonstrated in vitro in type 1 human Ewing's sarcoma tumor cell lines with the optimal bi-shRNA EWS/FLI1 plasmid. This functional plasmid was placed in a clinically tested, liposomal (LP) delivery vehicle followed by in vivo verification of activity. Type 1 Ewing's sarcoma xenograft modeling confirmed dose related safety and tumor response to pbi-shRNA EWS/FLI1 LPX. Toxicology studies in mini-pigs with doses comparable to the demonstrated in vivo efficacy dose resulted in transient fever, occasional limited hypertension at low- and high-dose assessment and transient liver enzyme elevation at high dose. These results provide the justification to initiate clinical testing. PMID:27166877

Tiny Hiccups To Titanic Explosions: Tackling Transients in Anomalous X-ray Pulsars

NASA Astrophysics Data System (ADS)

Kaspi, Victoria

2006-09-01

Recently discovered transient events in Anomalous X-ray Pulsars (AXPs) may be a Rosetta Stone for understanding the persistent emission from magnetars. They also may hold the key to quantifying the number of magnetars in the Galaxy. Here we request Chandra TOO time to observe any AXP following a rare transient event, including a major outburst or a long-duration flare. Specifically, the requested observations will determine the pulsed fraction and spectral evolution of a transient AXP event as the source relaxes back to quiescence, in order to quantitatively test the "twisted magnetosphere" model for magnetars, and establish the basic phenomenology of transient AXP events.

TINY HICCUPS TO TITANIC EXPLOSIONS: Tackling Transients in Anomalous X-ray Pulsars

NASA Astrophysics Data System (ADS)

Kaspi, Victoria

2007-09-01

Recently discovered transient events in Anomalous X-ray Pulsars (AXPs) may be a Rosetta Stone for understanding the persistent emission from magnetars. They also may hold the key to quantifying the number of magnetars in the Galaxy. Here we request Chandra TOO time to observe any AXP following a rare transient event, including a major outburst or a long-duration flare. Specifically, the requested observations will determine the pulsed fraction and spectral evolution of a transient AXP event as the source relaxes back to quiescence, in order to quantitatively test the "twisted magnetosphere" model for magnetars, and establish the basic phenomenology of transient AXP events.

Experimental transient turbine blade temperatures in a research engine for gas stream temperatures cycling between 1067 and 1567 k

NASA Technical Reports Server (NTRS)

Gauntner, D. J.; Yeh, F. C.

1975-01-01

Experimental transient turbine blade temperatures were obtained from tests conducted on air-cooled blades in a research turbojet engine, cycling between cruise and idle conditions. Transient data were recorded by a high speed data acquisition system. Temperatures at the same phase of each transient cycle were repeatable between cycles to within 3.9 K (7 F). Turbine inlet pressures were repeatable between cycles to within 0.32 N/sq cm (0.47 psia). The tests were conducted at a gas stream temperature of 1567 K (2360 F) at cruise, and 1067 K (1460 F) at idle conditions. The corresponding gas stream pressures were about 26.2 and 22.4 N/sq cm (38 and 32.5 psia) respectively. The nominal coolant inlet temperature was about 811 K (1000 F).

Single-Event Transient Testing of the Crane Aerospace and Electronics SMHF2812D Dual DC-DC Converter

NASA Technical Reports Server (NTRS)

Casey, Megan

2015-01-01

The purpose of this testing was to characterize the Crane Aerospace & Electronics (Crane) Interpoint SMHF2812D for single-event transient (SET) susceptibility. These data shall be used for flight lot evaluation, as well as qualification by similarity of the SMHF family of converters, all of which use the same active components.

Transient Anosmia Induces Depressive-like and Anxiolytic-like Behavior and Reduces Amygdalar Corticotropin-Releasing Hormone in a ZnSO4-Induced Mouse Model.

PubMed

Ahn, Sangzin; Choi, Mooseok; Kim, Hyunju; Yang, Eun-Jeong; Mahmood, Usman; Kang, Seong-Il; Shin, Hyun-Woo; Kim, Dae Woo; Kim, Hye-Sun

2018-04-23

Olfactory loss is known to affect both mood and quality of life. Transient anosmia was induced in mice to study the resulting changes in mood, behavior, and on a molecular level. Transient anosmia was induced by a single intranasal instillation of ZnSO4 in BALB/c mice. Hematoxylin and eosin (HE) staining, and potato chip finding test were performed to confirm olfactory loss. Tail suspension, forced swim, and splash tests were performed to evaluate depression-related behavior; while the open field, and elevated plus maze tests were used to evaluate anxiety-related behavior. The mRNA levels of amygdalar corticotropin-releasing hormone (CRH) and hypothalamic glucocorticoid receptor (GR) were quantified using real-time PCR to confirm relevant molecular change. Olfactory loss was confirmed 1-2.5 weeks after induction, and this loss was subsequently reversed over time. The results of the behavioral tests indicated increased depression-like and reduced anxiety-like behavior at week 1. Accordingly, PCR data identified decreased amygdalar CRH expression at week 1. These results suggest that transient anosmia induces both depressive and anxiolytic behavior as a result of decreased amygdalar CRH in a mouse model of anosmia.

Laser-based irradiation apparatus and method to measure the functional dose-rate response of semiconductor devices

DOEpatents

Horn, Kevin M [Albuquerque, NM

2008-05-20

A broad-beam laser irradiation apparatus can measure the parametric or functional response of a semiconductor device to exposure to dose-rate equivalent infrared laser light. Comparisons of dose-rate response from before, during, and after accelerated aging of a device, or from periodic sampling of devices from fielded operational systems can determine if aging has affected the device's overall functionality. The dependence of these changes on equivalent dose-rate pulse intensity and/or duration can be measured with the apparatus. The synchronized introduction of external electrical transients into the device under test can be used to simulate the electrical effects of the surrounding circuitry's response to a radiation exposure while exposing the device to dose-rate equivalent infrared laser light.

Mixing and transient interface condensation of a liquid hydrogen tank

NASA Technical Reports Server (NTRS)

Lin, C. S.; Hasan, M. M.; Nyland, T. W.

1993-01-01

Experiments were conducted to investigate the effect of axial jet-induced mixing on the pressure reduction of a thermally stratified liquid hydrogen tank. The tank was nearly cylindrical, having a volume of about 0.144 cu m with 0.559 m in diameter and 0.711 m long. A mixer/pump unit, which had a jet nozzle outlet of 0.0221 m in diameter was located 0.178 m from the tank bottom and was installed inside the tank to generate the axial jet mixing and tank fluid circulation. The liquid fill and jet flow rate ranged from 42 to 85 percent (by volume) and 0.409 to 2.43 cu m/hr, respectively. Mixing tests began with the tank pressure ranging from 187.5 to 238.5 kPa at which the thermal stratification results in 4.9 to 6.2 K liquid sub cooling. The mixing time and transient vapor condensation rate at the liquid-vapor interface are determined. Two mixing time correlations, based on the thermal equilibrium and pressure equilibrium, are developed. Both mixing time correlations are expressed as functions of system and buoyancy parameters and compared well with other experimental data. The steady state condensation rate correlation of Sonin et al. based on steam-water data is modified and expressed as a function of jet subcooling. The limited liquid hydrogen data of the present study shows that the modified steady state condensation rate correlation may be used to predict the transient condensation rate in a mixing process if the instantaneous values of jet sub cooling and turbulence intensity at the interface are employed.

Specification and testing for power by wire aircraft

NASA Technical Reports Server (NTRS)

Hansen, Irving G.; Kenney, Barbara H.

1993-01-01

A power by wire aircraft is one in which all active functions other than propulsion are implemented electrically. Other nomenclature are 'all electric airplane,' or 'more electric airplane.' What is involved is the task of developing and certifying electrical equipment to replace existing hydraulics and pneumatics. When such functions, however, are primary flight controls which are implemented electrically, new requirements are imposed that were not anticipated by existing power system designs. Standards of particular impact are the requirements of ultra-high reliability, high peak transient bi-directional power flow, and immunity to electromagnetic interference and lightning. Not only must the electromagnetic immunity of the total system be verifiable, but box level tests and meaningful system models must be established to allow system evaluation. This paper discusses some of the problems, the system modifications involved, and early results in establishing wiring harness and interface susceptibility requirements.

International Symposium on Electromagnetic Compatibility, 25th, Arlington, VA, August 23-25, 1983, Symposium Record

NASA Astrophysics Data System (ADS)

Subjects related to electromagnetic compatibility (EMC) analysis are discussed, taking into account forcing terms of line equations for externally excited transmission lines, E-fields over ground, electromagnetic near fields as a function of electrical size, a program for experimental verification of EMC analysis models, random susceptability of an IC 7400 TTL NAND gate, and a comparison of IEMCAP and SEMCAP. Other topics explored are concerned with EMC measurements, spectrum management, the electromagnetic pulse (EMP), a Navy EMC program, measurement systems, filters, EMC design, electromagnetic vulnerability (EMV) assessment of weapon systems, FCC rules and regulations, shielding, and electromagnetic interference (EMI) in communication systems. Attention is also given to nonsinusoidal functions in radar and communications, transients/electrostatic discharge, open field testing, cables and connectors, interference effects of induced and conducted earth current at dc and ELF, test cells, and cable coupling.

Blade loss transient dynamics analysis, volume 2. Task 2: Theoretical and analytical development. Task 3: Experimental verification

NASA Technical Reports Server (NTRS)

Gallardo, V. C.; Storace, A. S.; Gaffney, E. F.; Bach, L. J.; Stallone, M. J.

1981-01-01

The component element method was used to develop a transient dynamic analysis computer program which is essentially based on modal synthesis combined with a central, finite difference, numerical integration scheme. The methodology leads to a modular or building-block technique that is amenable to computer programming. To verify the analytical method, turbine engine transient response analysis (TETRA), was applied to two blade-out test vehicles that had been previously instrumented and tested. Comparison of the time dependent test data with those predicted by TETRA led to recommendations for refinement or extension of the analytical method to improve its accuracy and overcome its shortcomings. The development of working equations, their discretization, numerical solution scheme, the modular concept of engine modelling, the program logical structure and some illustrated results are discussed. The blade-loss test vehicles (rig full engine), the type of measured data, and the engine structural model are described.

Results of an On-Going Long Duration Ground Test of the DS1 Flight Spare Engine

NASA Technical Reports Server (NTRS)

Anderson, John R.; Goodfellow, Keith D.; Polk, James E.; Shotwell, Robert F.; Rawlin, Vincent K.; Sovey, James S.; Patterson, Michael J.

2000-01-01

Ground testing of the DS1 night spare thruster (FT2) is presently being conducted. To date, the thruster has accumulated over 4500 hours of operation. Comparison of FT2 with the performance of the engineering model thruster 2 (EMT2) during the 8.2 khr test shows a transient, lasting for about 3000 hours, during which the discharge chamber efficiency decreases for both thrusters. The flow rates are 2% lower for FT2 than for EMT2 and the discharge chamber performance is 4.5% lower for FT2 during the transient. Sensitivity data obtained during the test show that the lower flow rate accounts for about half of the observed difference. After the initial transients decay, the performance of both thrusters is comparable with the exception of the electron backstreaming margin--which is 6 V lower for FT2.

Reduced auditory efferent activity in childhood selective mutism.

PubMed

Bar-Haim, Yair; Henkin, Yael; Ari-Even-Roth, Daphne; Tetin-Schneider, Simona; Hildesheimer, Minka; Muchnik, Chava

2004-06-01

Selective mutism is a psychiatric disorder of childhood characterized by consistent inability to speak in specific situations despite the ability to speak normally in others. The objective of this study was to test whether reduced auditory efferent activity, which may have direct bearings on speaking behavior, is compromised in selectively mute children. Participants were 16 children with selective mutism and 16 normally developing control children matched for age and gender. All children were tested for pure-tone audiometry, speech reception thresholds, speech discrimination, middle-ear acoustic reflex thresholds and decay function, transient evoked otoacoustic emission, suppression of transient evoked otoacoustic emission, and auditory brainstem response. Compared with control children, selectively mute children displayed specific deficiencies in auditory efferent activity. These aberrations in efferent activity appear along with normal pure-tone and speech audiometry and normal brainstem transmission as indicated by auditory brainstem response latencies. The diminished auditory efferent activity detected in some children with SM may result in desensitization of their auditory pathways by self-vocalization and in reduced control of masking and distortion of incoming speech sounds. These children may gradually learn to restrict vocalization to the minimal amount possible in contexts that require complex auditory processing.

Experimental investigations of the time and flow-direction responses of shear-stress-sensitive liquid crystal coatings

NASA Technical Reports Server (NTRS)

Reda, Daniel C.; Muratore, Joseph J., Jr.; Heineck, James T.

1993-01-01

Time and flow-direction responses of shearstress-sensitive liquid crystal coatings were explored experimentally. For the time-response experiments, coatings were exposed to transient, compressible flows created during the startup and off-design operation of an injector-driven supersonic wind tunnel. Flow transients were visualized with a focusing Schlieren system and recorded with a 1000 frame/sec color video camera. Liquid crystal responses to these changing-shear environments were then recorded with the same video system, documenting color-play response times equal to, or faster than, the time interval between sequential frames (i.e., 1 millisecond). For the flow-direction experiments, a planar test surface was exposed to equal-magnitude and known-direction surface shear stresses generated by both normal and tangential subsonic jet-impingement flows. Under shear, the sense of the angular displacement of the liquid crystal dispersed (reflected) spectrum was found to be a function of the instantaneous direction of the applied shear. This technique thus renders dynamic flow reversals or flow divergences visible over entire test surfaces at image recording rates up to 1 KHz. Extensions of the technique to visualize relatively small changes in surface shear stress direction appear feasible.

A single, mild, transient scrotal heat stress causes DNA damage, subfertility and impairs formation of blastocysts in mice.

PubMed

Paul, Catriona; Murray, Alison A; Spears, Norah; Saunders, Philippa T K

2008-07-01

Infertility represents a major clinical problem and 50% of cases are attributable to the male partner. Testicular function is temperature dependent, and in both man and mouse the position of the testes in the scrotum ensures that they are kept at between 2 and 8 degrees C below core body temperature. We used a mouse model to investigate the impact of a single, transient, mild, scrotal heat stress (38, 40 or 42 degrees C for 30 min) on testicular function, sperm DNA integrity and embryo survival. We detected temperature-dependent changes in testicular architecture, number of apoptotic cells and a significant reduction in testis weight 7 and 14 days after heat stress at 42 degrees C. We report for the first time that DNA strand breaks (gamma-H2AX-positive foci) were present in spermatocytes recovered from testes subjected to 40 or 42 degrees C. Fertility of heat-stressed males was tested 23-28 d after treatment (sperm at this time would have been spermatocytes at time of heating). Paternal heat stress at 42 degrees C resulted in reduced pregnancy rate, placental weight and litter size; pregnancies from the 40 degrees C group had increased resorptions at e14.5. Abnormalities in embryonic development were detected at e3.5 and in vitro fertilisation with sperm recovered 16 h or 23 d after scrotal stress at 42 degrees C revealed a block in development between the 4-cell and blastocyst stages. This study has provided evidence of temperature-dependent effects on germ cell DNA integrity and highlighted the importance of an intact paternal genome for normal embryo development.

Transient response of multidegree-of-freedom linear systems to forcing functions with inequality constraints

NASA Technical Reports Server (NTRS)

Michalopoulos, C. D.

1974-01-01

Optimal control theory is applied to analyze the transient response of discrete linear systems to forcing functions with unknown time dependence but having known bounds. Particular attention is given to forcing functions which include: (1) maximum displacement of any given mass element, (2) maximum relative displacement of any two adjacent masses, and (3) maximum acceleration of a given mass. Linear mechanical systems with an arbitrary number of degrees of freedom and only one forcing function acting are considered. In the general case, the desired forcing function is found to be a function that switches from the upper-to-lower bound and vice-versa at certain moments of time. A general procedure for finding such switching times is set forth.

Tests of an alternating current propulsion subsystem for electric vehicles on a road load simulator

NASA Astrophysics Data System (ADS)

Stenger, F. J.

1982-12-01

The test results of a breadboard version of an ac electric-vehicle propulsion subsystem are presented. The breadboard was installed in the NASA Lewis Research Center Road Load Simulator facility and tested under steady-state and transient conditions. Steady-state tests were run to characterize the system and component efficiencies over the complete speed-torque range within the capability of the propulsion subsystem in the motoring mode of operation. Transient tests were performed to determine the energy consumption of the breadboard over the acceleration and cruise portions of SAE J227 and driving schedules B, C, and D. Tests in the regenerative mode were limited to the low-gear-speed range of the two speed transaxle used in the subsystem. The maximum steady-state subsystem efficiency observed for the breadboard was 81.5 percent in the high-gear-speed range in the motoring mode, and 76 percent in the regenerative braking mode (low gear). The subsystem energy efficiency during the transient tests ranged from 49.2 percent for schedule B to 68.4 percent for Schedule D.

Tests of an alternating current propulsion subsystem for electric vehicles on a road load simulator

NASA Technical Reports Server (NTRS)

Stenger, F. J.

1982-01-01

The test results of a breadboard version of an ac electric-vehicle propulsion subsystem are presented. The breadboard was installed in the NASA Lewis Research Center Road Load Simulator facility and tested under steady-state and transient conditions. Steady-state tests were run to characterize the system and component efficiencies over the complete speed-torque range within the capability of the propulsion subsystem in the motoring mode of operation. Transient tests were performed to determine the energy consumption of the breadboard over the acceleration and cruise portions of SAE J227 and driving schedules B, C, and D. Tests in the regenerative mode were limited to the low-gear-speed range of the two speed transaxle used in the subsystem. The maximum steady-state subsystem efficiency observed for the breadboard was 81.5 percent in the high-gear-speed range in the motoring mode, and 76 percent in the regenerative braking mode (low gear). The subsystem energy efficiency during the transient tests ranged from 49.2 percent for schedule B to 68.4 percent for Schedule D.

Simulation of IST Turbomachinery Power-Neutral Tests with the ANL Plant Dynamics Code

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

Moisseytsev, A.; Sienicki, J. J.

The validation of the Plant Dynamics Code (PDC) developed at Argonne National Laboratory (ANL) for the steady-state and transient analysis of supercritical carbon dioxide (sCO2) systems has been continued with new test data from the Naval Nuclear Laboratory (operated by Bechtel Marine Propulsion Corporation) Integrated System Test (IST). Although data from three runs were provided to ANL, only two of the data sets were analyzed and described in this report. The common feature of these tests is the power-neutral operation of the turbine-compressor shaft, where no external power through the alternator was provided during the tests. Instead, the shaft speedmore » was allowed to change dictated by the power balance between the turbine, the compressor, and the power losses in the shaft. The new test data turned out to be important for code validation for several reasons. First, the power-neutral operation of the shaft allows validation of the shaft dynamics equations in asynchronous mode, when the shaft is disconnected from the grid. Second, the shaft speed control with the compressor recirculation (CR) valve not only allows for testing the code control logic itself, but it also serves as a good test for validation of both the compressor surge control and the turbine bypass control actions, since the effect of the CR action on the loop conditions is similar for both of these controls. Third, the varying compressor-inlet temperature change test allows validation of the transient response of the precooler, a shell-and-tube heat exchanger. The first transient simulation of the compressor-inlet temperature variation Test 64661 showed a much slower calculated response of the precooler in the calculations than the test data. Further investigation revealed an error in calculating the heat exchanger tube mass for the PDC dynamic equations that resulted in a slower change in the tube wall temperature than measured. The transient calculations for both tests were done in two steps. The first step was done in the same fashion as the FY15 IST analysis, where the CR valve position and the turbine-compressor shaft speed were specified through the PDC input based on the test values. On the second step, the turbine-compressor shaft dynamics equations were invoked by specifying that the shaft is disconnected from the grid. In addition, the CR valve control was used to control the shaft speed, based on the turbine bypass control logic already implemented in the PDC. For the shaft power balance, the friction (windage) loss is calculated based on the shaft balance at the steady-state conditions and is assumed to be scaled to the third power of shaft speed in the transient. Both the steady-state and transient simulations of both tests showed good agreement with the test data. The only significant difference was the turbine performance, which was not predicted as well as it was in the previous IST simulation, resulting in the prediction of a somewhat different flow split between the two turbines. This flow split difference is believed to be the result of not addressing the recent turbine modifications in the model. In addition, the full simulation of the turbine-compressor speed variation Test 65261-P with shaft speed control showed greater a difference with the test data later in the transient than the other test. Further analysis of the results revealed that this difference is most likely due to scaling the shaft windage losses only with the shaft speed and ignoring its dependency on the fluid density in the shaft cavity. Based on the results of steady state and transient calculations of the Tests 64661 and 65216-P, several areas of future improvements for the PDC simulation of the IST are identified.« less

Transient adhesion in a non-fully detached contact.

PubMed

Liu, Zheyu; Lu, Hongyu; Zheng, Yelong; Tao, Dashuai; Meng, Yonggang; Tian, Yu

2018-04-18

Continuous approaching and detaching displacement usually occurs in an adhesion test. Here, we found a transient adhesion force at the end of a non-fully detached contact. This force occurred when the nominal detaching displacement was less than the traditional quasi-static theory predicted zero force point. The transient adhesion force was ascribed to interfacial adhesion hysteresis, which was caused by the cracking process of the contact and the deformation competition between the sphere and supporting spring. Results indicated that the testing of adhesion can be significantly affected by different combinations of stiffnesses of the contact objects and the supporting spring cantilever. This combination should be carefully designed in an adhesion test. All these results enabled increased understanding of the nature of adhesion and can guide the design of adhesive actuators.

Impact of exercise programs among helicopter pilots with transient LBP.

PubMed

Andersen, Knut; Baardsen, Roald; Dalen, Ingvild; Larsen, Jan Petter

2017-06-20

Flight related low back pain (LBP) among helicopter pilots is frequent and may influence flight performance. Prolonged confined sitting during flights seems to weaken lumbar trunk (LT) muscles with associated secondary transient pain. Aim of the study was to investigate if structured training could improve muscular function and thus improve LBP related to flying. 39 helicopter pilots (35 men and 4 women), who reported flying related LBP on at least 1 of 3 missions last month, were allocated to two training programs over a 3-month period. Program A consisted of 10 exercises recommended for general LBP. Program B consisted of 4 exercises designed specifically to improve LT muscular endurance. The pilots were examined before and after the training using questionnaires for pain, function, quality of health and tests of LT muscular endurance as well as ultrasound measurements of the contractility of the lumbar multifidus muscle (LMM). Approximately half of the participants performed the training per-protocol. Participants in this subset group had comparable baseline characteristics as the total study sample. Pre and post analysis of all pilots included, showed participants had marked improvement in endurance and contractility of the LMM following training. Similarly, participants had improvement in function and quality of health. Participants in program B had significant improvement in pain, function and quality of health. This study indicates that participants who performed a three months exercise program had improved muscle endurance at the end of the program. The helicopter pilots also experienced improved function and quality of health. Identifier: NCT01788111 Registration date; February 5th, 2013, verified April 2016.

Digital system upset. The effects of simulated lightning-induced transients on a general-purpose microprocessor

NASA Technical Reports Server (NTRS)

Belcastro, C. M.

1983-01-01

Flight critical computer based control systems designed for advanced aircraft must exhibit ultrareliable performance in lightning charged environments. Digital system upset can occur as a result of lightning induced electrical transients, and a methodology was developed to test specific digital systems for upset susceptibility. Initial upset data indicates that there are several distinct upset modes and that the occurrence of upset is related to the relative synchronization of the transient input with the processing sate of the digital system. A large upset test data base will aid in the formulation and verification of analytical upset reliability modeling techniques which are being developed.

A VLA (Very Large Array) Search for 5 GHz Radio Transients and Variables at Low Galactic Latitudes

NASA Technical Reports Server (NTRS)

Ofek, E. O.; Frail, D. A.; Breslauer, B.; Kulkarni, S. R.; Chandra, P.; Gal-Yam, A.; Kasliwal, M. M.; Gehrels, N.

2012-01-01

We present the results of a 5GHz survey with the Very Large Array (VLA) and the expanded VLA, designed to search for short-lived (approx < 1 day) transients and to characterize the variability of radio sources at milli-Jansky levels. A total sky area of 2.66 sq. deg, spread over 141 fields at low Galactic latitudes (b approx equals 6 - 8 deg) was observed 16 times with a cadence that was chosen to sample timescales of days, months and years. Most of the data were reduced, analyzed and searched for transients in near real time. Interesting candidates were followed up using visible light telescopes (typical delays of 1 - 2 hr) and the X-Ray Telescope on board the Swift satellite. The final processing of the data revealed a single possible transient with a flux density of f(sub v) approx equals 2.4mJy. This implies a transients sky surface density of kappa(f(sub v) > 1.8mJy) = 0.039(exp +0.13,+0.18) (sub .0.032,.0.038) / sq. deg (1, 2 sigma confidence errors). This areal density is consistent with the sky surface density of transients from the Bower et al. survey extrapolated to 1.8mJy. Our observed transient areal density is consistent with a Neutron Stars (NSs) origin for these events. Furthermore, we use the data to measure the sources variability on days to years time scales, and we present the variability structure function of 5GHz sources. The mean structure function shows a fast increase on approximately 1 day time scale, followed by a slower increase on time scales of up to 10 days. On time scales between 10 - 60 days the structure function is roughly constant. We find that approx > 30% of the unresolved sources brighter than 1.8mJy are variable at the > 4-sigma confidence level, presumably due mainly to refractive scintillation.

Test prediction for the German PKL Test K5A using RELAP4/MOD6

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

Chen, Y.S.; Haigh, W.S.; Sullivan, L.H.

RELAP4/MOD6 is the most recent modification in the series of RELAP4 computer programs developed to describe the thermal-hydraulic conditions attendant to postulated transients in light water reactor systems. The major new features in RELAP4/MOD6 include best-estimate pressurized water reactor (PWR) reflood transient analytical models for core heat transfer, local entrainment, and core vapor superheat, and a new set of heat transfer correlations for PWR blowdown and reflood. These new features were used for a test prediction of the Kraftwerk Union three-loop PRIMAR KREISLAUF (PKL) Reflood Test K5A. The results of the prediction were in good agreement with the experimental thermalmore » and hydraulic system data. Comparisons include heater rod surface temperature, system pressure, mass flow rates, and core mixture level. It is concluded that RELAP4/MOD6 is capable of accurately predicting transient reflood phenomena in the 200% cold-leg break test configuration of the PKL reflood facility.« less

Tribological investigations of the load, temperature, and time dependence of wear in sliding contact.

PubMed

Marko, Matthew David; Kyle, Jonathan P; Wang, Yuanyuan Sabrina; Terrell, Elon J

2017-01-01

An effort was made to study and characterize the evolution of transient tribological wear in the presence of sliding contact. Sliding contact is often characterized experimentally via the standard ASTM D4172 four-ball test, and these tests were conducted for varying times ranging from 10 seconds to 1 hour, as well as at varying temperatures and loads. A numerical model was developed to simulate the evolution of wear in the elastohydrodynamic regime. This model uses the results of a Monte Carlo study to develop novel empirical equations for wear rate as a function of asperity height and lubricant thickness; these equations closely represented the experimental data and successfully modeled the sliding contact.

Silicon Carbide Diodes Performance Characterization and Comparison With Silicon Devices

NASA Technical Reports Server (NTRS)

Lebron-Velilla, Ramon C.; Schwarze, Gene E.; Trapp, Scott

2003-01-01

Commercially available silicon carbide (SiC) Schottky diodes from different manufacturers were electrically tested and characterized at room temperature. Performed electrical tests include steady state forward and reverse I-V curves, as well as switching transient tests performed with the diodes operating in a hard switch dc-to-dc buck converter. The same tests were performed in current state of the art silicon (Si) and gallium arsenide (GaAs) Schottky and pn junction devices for evaluation and comparison purposes. The SiC devices tested have a voltage rating of 200, 300, and 600 V. The comparison parameters are forward voltage drop at rated current, reverse current at rated voltage and peak reverse recovery currents in the dc to dc converter. Test results show that steady state characteristics of the tested SiC devices are not superior to the best available Si Schottky and ultra fast pn junction devices. Transient tests reveal that the tested SiC Schottky devices exhibit superior transient behavior. This is more evident at the 300 and 600 V rating where SiC Schottky devices showed drastically lower reverse recovery currents than Si ultra fast pn diodes of similar rating.

Conducted Transients on Spacecraft Primary Power Lines

NASA Technical Reports Server (NTRS)

Mc Closkey, John; Dimov, Jen

2017-01-01

One of the sources of potential interference on spacecraft primary power lines is that of conducted transients resulting from equipment being switched on and off of the bus. Susceptibility to such transients is addressed by some version of the CS06 requirement of MIL-STD-461462. This presentation provides a summary of the history of the CS06 requirement and test method, a basis for understanding of the sources of these transients, analysis techniques for determining their worst-case characteristics, and guidelines for minimizing their magnitudes and applying the requirement appropriately.

Long QT syndrome type 5-Lite: Defining the clinical phenotype associated with the potentially proarrhythmic p.Asp85Asn-KCNE1 common genetic variant.

PubMed

Lane, Conor; Giudicessi, John R; Ye, Dan; Tester, David J; Rohatgi, Ram K; Bos, J Martijn; Ackerman, Michael J

2018-04-03

Long QT syndrome (LQTS) genetic test reports commonly exclude potentially proarrhythmic common variants such as p.Asp85Asn-KCNE1. The purpose of this study was to determine whether a discernible phenotype is associated with p.Asp85Asn-KCNE1 and whether relatively common KCNE1 variants underlie transient QT prolongation pedigrees with negative commercial LQTS genetic tests. Retrospective review was used to compare demographics, symptomatology, and QT parameters of individuals with p.Asp85Asn-KCNE1 in the absence of other rare/ultra-rare variants in LQTS-susceptibility genes and those who underwent comprehensive LQTS genetic testing. Compared to the Genome Aggregation Database, p.Asp85Asn-KCNE1 was more prevalent in individuals undergoing LQTS genetic testing (33/1248 [2.6%] vs 1552/126,652 [1.2%]; P = .0001). In 19 of 33 patients (58%), only p.Asp85Asn-KCNE1 was observed. These patients were predominantly female (90% vs 62%; P = .02) and were less likely to experience syncope (0% vs 34%; P = .0007), receive β-blockers (53% vs 85%; P = .001), or require an implantable cardioverter-defibrillator (5.3% vs 33%; P = .01). However, they exhibited a similar degree of QT prolongation (QTc 460 ms vs 467 ms; P = NS). Whole exome sequencing of 2 commercially genotype-negative pedigrees revealed that p.Asp85Asn-KCNE1 and p.Arg36His-KCNE1 traced with a transient QT prolongation phenotype. Functional characterization of p.Arg36His-KCNE1 demonstrated loss of function, with a 47% reduction in peak I Ks current density in the heterozygous state. We provide further evidence that relatively common variants in KCNE1 may result in a mild QT phenotype designated as "LQT5-Lite" to distinguish such potentially proarrhythmic common variants (ie, functional risk alleles) from rare pathogenic variants that truly confer monogenic disease susceptibility, albeit with incomplete penetrance. Copyright © 2018. Published by Elsevier Inc.

Transient and persistent worsening renal function during hospitalization for acute heart failure.

PubMed

Krishnamoorthy, Arun; Greiner, Melissa A; Sharma, Puza P; DeVore, Adam D; Johnson, Katherine Waltman; Fonarow, Gregg C; Curtis, Lesley H; Hernandez, Adrian F

2014-12-01

Transient and persistent worsening renal function (WRF) may be associated with different risks during hospitalization for acute heart failure. We compared outcomes of patients hospitalized for acute heart failure with transient, persistent, or no WRF. We identified patients 65 years or older hospitalized with acute heart failure from a clinical registry linked to Medicare claims data. We defined WRF as an increase in serum creatinine of ≥ 0.3 mg/dL after admission. We further classified patients with WRF by the difference between admission and last recorded serum creatinine levels into transient WRF (< 0.3 mg/dL) or persistent WRF (≥ 0.3 mg/dL). We examined unadjusted rates and adjusted associations between 90-day outcomes and WRF status. Among 27,309 patients, 18,568 (68.0%) had no WRF, 3,205 (11.7%) had transient WRF, and 5,536 (20.3%) had persistent WRF. Patients with WRF had higher observed rates of 90-day postdischarge all-cause readmission and 90-day postadmission mortality (P < .001). After multivariable adjustment, transient WRF (hazard ratio [HR] 1.19, 99% CI 1.05-1.35) and persistent WRF (HR 1.73, 99% CI 1.57-1.91) were associated with higher risks of 90-day postadmission mortality (P < .001 for both). Compared with transient WRF, persistent WRF was associated with a higher risk of 90-day postadmission mortality (HR 1.46, 99% CI 1.28-1.66, P < .001). Transient and persistent WRF during hospitalization for acute heart failure were associated with higher adjusted risks for 90-day all-cause postadmission mortality. Patients with persistent WRF had worse outcomes. Copyright © 2014 Elsevier Inc. All rights reserved.

Transient Thermal Testing and Analysis of a Thermally Insulating Structural Sandwich Panel

NASA Technical Reports Server (NTRS)

Blosser, Max L.; Daryabeigi, Kamran; Bird, Richard K.; Knutson, Jeffrey R.

2015-01-01

A core configuration was devised for a thermally insulating structural sandwich panel. Two titanium prototype panels were constructed to illustrate the proposed sandwich panel geometry. The core of one of the titanium panels was filled with Saffil(trademark) alumina fibrous insulation and the panel was tested in a series of transient thermal tests. Finite element analysis was used to predict the thermal response of the panel using one- and two-dimensional models. Excellent agreement was obtained between predicted and measured temperature histories.

Testing For EM Upsets In Aircraft Control Computers

NASA Technical Reports Server (NTRS)

Belcastro, Celeste M.

1994-01-01

Effects of transient electrical signals evaluated in laboratory tests. Method of evaluating nominally fault-tolerant, aircraft-type digital-computer-based control system devised. Provides for evaluation of susceptibility of system to upset and evaluation of integrity of control when system subjected to transient electrical signals like those induced by electromagnetic (EM) source, in this case lightning. Beyond aerospace applications, fault-tolerant control systems becoming more wide-spread in industry; such as in automobiles. Method supports practical, systematic tests for evaluation of designs of fault-tolerant control systems.

The paradox of transient worsening renal function in patients with acute heart failure: the role of B-type natriuretic peptide and diuretic response.

PubMed

Ruocco, Gaetano; Nuti, Ranuccio; Giambelluca, Amalia; Evangelista, Isabella; De Vivo, Oreste; Daniello, Cosimo; Palazzuoli, Alberto

2017-11-01

Worsening renal function (WRF) occurs in one-third of patients hospitalized for acute decompensated heart failure. Recently, WRF was categorized in two subtypes: persistent and transient WRF. Thus, we sought to investigate the different prognostic impact of persistent vs. transient WRF; we also evaluate the relation of two WRF phenotypes with congestion, B-type natriuretic peptide (BNP) changes, and diuretic response at discharge. The prospective was a single centre study including patients screened for interventional Diur-heart failure Trial (NCT01441245). Patients were eligible if they were admitted with a primary diagnosis of acute heart failure with evidence of volume overload. Persistent WRF was defined as a sustained creatinine increase by at least 0.3 mg/dl throughout the hospitalisation; transient WRF was defined as creatinine increase by at least 0.3 mg/dl within 72 h and a return to baseline levels at discharge. Patients were followed for 6 months after discharge. Our population included 192 acute decompensated heart failure patients. In total, 61 patients developed persistent WRF and 29 developed transient WRF. Patients with persistent WRF showed a lower mean urine output with respect to the transient WRF group and patients with preserved renal function (1618 ± 374 vs. 2132 ± 392 vs. 2075 ± 442 ml; P < 0.001). Similarly, patients with transient WRF demonstrated a higher rate of BNP decrease more than 30% than seen in patients with stable creatinine levels and in the persistent WRF group (95 vs. 76 vs. 54%; P = 0.001). Univariate Cox regression analysis demonstrated that BNP decrease less than 30% [HR 2.15 (1.40-3.40); P < 0.001] and persistent WRF [HR 1.70 (1.11-2.61); P = 0.01] were related to poor outcome; conversely, transient WRF should be considered as a protective factor [HR 0.42 (0.19-0.93); P = 0.03]. In the multivariable model, only persistent WRF appeared to be related to poor prognosis [HR 1.61 (1.02-2.57); P = 0.04]. WRF occurring during hospitalization has a different significance: transient deterioration appears to be associated with a favourable clinical course; conversely, persistent WRF is related to poor outcome.

Temporal Control over Transient Chemical Systems using Structurally Diverse Chemical Fuels.

PubMed

Chen, Jack L-Y; Maiti, Subhabrata; Fortunati, Ilaria; Ferrante, Camilla; Prins, Leonard J

2017-08-25

The next generation of adaptive, intelligent chemical systems will rely on a continuous supply of energy to maintain the functional state. Such systems will require chemical methodology that provides precise control over the energy dissipation process, and thus, the lifetime of the transiently activated function. This manuscript reports on the use of structurally diverse chemical fuels to control the lifetime of two different systems under dissipative conditions: transient signal generation and the transient formation of self-assembled aggregates. The energy stored in the fuels is dissipated at different rates by an enzyme, which installs a dependence of the lifetime of the active system on the chemical structure of the fuel. In the case of transient signal generation, it is shown that different chemical fuels can be used to generate a vast range of signal profiles, allowing temporal control over two orders of magnitude. Regarding self-assembly under dissipative conditions, the ability to control the lifetime using different fuels turns out to be particularly important as stable aggregates are formed only at well-defined surfactant/fuel ratios, meaning that temporal control cannot be achieved by simply changing the fuel concentration. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mechanistic prediction of fission-gas behavior during in-cell transient heating tests on LWR fuel using the GRASS-SST and FASTGRASS computer codes

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

Rest, J; Gehl, S M

1979-01-01

GRASS-SST and FASTGRASS are mechanistic computer codes for predicting fission-gas behavior in UO/sub 2/-base fuels during steady-state and transient conditions. FASTGRASS was developed in order to satisfy the need for a fast-running alternative to GRASS-SST. Althrough based on GRASS-SST, FASTGRASS is approximately an order of magnitude quicker in execution. The GRASS-SST transient analysis has evolved through comparisons of code predictions with the fission-gas release and physical phenomena that occur during reactor operation and transient direct-electrical-heating (DEH) testing of irradiated light-water reactor fuel. The FASTGRASS calculational procedure is described in this paper, along with models of key physical processes included inmore » both FASTGRASS and GRASS-SST. Predictions of fission-gas release obtained from GRASS-SST and FASTGRASS analyses are compared with experimental observations from a series of DEH tests. The major conclusions is that the computer codes should include an improved model for the evolution of the grain-edge porosity.« less

An approximation technique for predicting the transient response of a second order nonlinear equation

NASA Technical Reports Server (NTRS)

Laurenson, R. M.; Baumgarten, J. R.

1975-01-01

An approximation technique has been developed for determining the transient response of a nonlinear dynamic system. The nonlinearities in the system which has been considered appear in the system's dissipation function. This function was expressed as a second order polynomial in the system's velocity. The developed approximation is an extension of the classic Kryloff-Bogoliuboff technique. Two examples of the developed approximation are presented for comparative purposes with other approximation methods.

The Volumetric Rate of Calcium-rich Transients in the Local Universe

DOE PAGES

Frohmaier, Chris; Sullivan, Mark; Maguire, Kate; ...

2018-05-04

Here, we present a measurement of the volumetric rate of "calcium-rich" optical transients in the local universe, using a sample of three events from the Palomar Transient Factory (PTF). This measurement builds on a detailed study of the PTF transient detection efficiencies and uses a Monte Carlo simulation of the PTF survey. We measure the volumetric rate of calcium-rich transients to be higher than previous estimates: 1.21 -0.39 +1.13 10 -5 events yr -1Mpc -3. This is equivalent to 33%-94% of the local volumetric Type Ia supernova rate. This calcium-rich transient rate is sufficient to reproduce the observed calcium abundancesmore » in galaxy clusters, assuming an asymptotic calcium yield per calcium-rich event of ~0.05 M ⊙. As a result, we also study the PTF detection efficiency of these transients as a function of position within their candidate host galaxies. We confirm as a real physical effect previous results that suggest that calcium-rich transients prefer large physical offsets from their host galaxies.« less

The Volumetric Rate of Calcium-rich Transients in the Local Universe

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

Frohmaier, Chris; Sullivan, Mark; Maguire, Kate

Here, we present a measurement of the volumetric rate of "calcium-rich" optical transients in the local universe, using a sample of three events from the Palomar Transient Factory (PTF). This measurement builds on a detailed study of the PTF transient detection efficiencies and uses a Monte Carlo simulation of the PTF survey. We measure the volumetric rate of calcium-rich transients to be higher than previous estimates: 1.21 -0.39 +1.13 10 -5 events yr -1Mpc -3. This is equivalent to 33%-94% of the local volumetric Type Ia supernova rate. This calcium-rich transient rate is sufficient to reproduce the observed calcium abundancesmore » in galaxy clusters, assuming an asymptotic calcium yield per calcium-rich event of ~0.05 M ⊙. As a result, we also study the PTF detection efficiency of these transients as a function of position within their candidate host galaxies. We confirm as a real physical effect previous results that suggest that calcium-rich transients prefer large physical offsets from their host galaxies.« less

Transient finite element modeling of functional electrical stimulation.

PubMed

Filipovic, Nenad D; Peulic, Aleksandar S; Zdravkovic, Nebojsa D; Grbovic-Markovic, Vesna M; Jurisic-Skevin, Aleksandra J

2011-03-01

Transcutaneous functional electrical stimulation is commonly used for strengthening muscle. However, transient effects during stimulation are not yet well explored. The effect of an amplitude change of the stimulation can be described by static model, but there is no differency for different pulse duration. The aim of this study is to present the finite element (FE) model of a transient electrical stimulation on the forearm. Discrete FE equations were derived by using a standard Galerkin procedure. Different tissue conductive and dielectric properties are fitted using least square method and trial and error analysis from experimental measurement. This study showed that FE modeling of electrical stimulation can give the spatial-temporal distribution of applied current in the forearm. Three different cases were modeled with the same geometry but with different input of the current pulse, in order to fit the tissue properties by using transient FE analysis. All three cases were compared with experimental measurements of intramuscular voltage on one volunteer.

Timing of myocardial trpm7 deletion during cardiogenesis variably disrupts adult ventricular function, conduction, and repolarization.

PubMed

Sah, Rajan; Mesirca, Pietro; Mason, Xenos; Gibson, William; Bates-Withers, Christopher; Van den Boogert, Marjolein; Chaudhuri, Dipayan; Pu, William T; Mangoni, Matteo E; Clapham, David E

2013-07-09

Transient receptor potential (TRP) channels are a superfamily of broadly expressed ion channels with diverse physiological roles. TRPC1, TRPC3, and TRPC6 are believed to contribute to cardiac hypertrophy in mouse models. Human mutations in TRPM4 have been linked to progressive familial heart block. TRPM7 is a divalent-permeant channel and kinase of unknown function, recently implicated in the pathogenesis of atrial fibrillation; however, its function in ventricular myocardium remains unexplored. We generated multiple cardiac-targeted knockout mice to test the hypothesis that TRPM7 is required for normal ventricular function. Early cardiac Trpm7 deletion (before embryonic day 9; TnT/Isl1-Cre) results in congestive heart failure and death by embryonic day 11.5 as a result of hypoproliferation of the compact myocardium. Remarkably, Trpm7 deletion late in cardiogenesis (about embryonic day 13; αMHC-Cre) produces viable mice with normal adult ventricular size, function, and myocardial transcriptional profile. Trpm7 deletion at an intermediate time point results in 50% of mice developing cardiomyopathy associated with heart block, impaired repolarization, and ventricular arrhythmias. Microarray analysis reveals elevations in transcripts of hypertrophy/remodeling genes and reductions in genes important for suppressing hypertrophy (Hdac9) and for ventricular repolarization (Kcnd2) and conduction (Hcn4). These transcriptional changes are accompanied by action potential prolongation and reductions in transient outward current (Ito; Kcnd2). Similarly, the pacemaker current (If; Hcn4) is suppressed in atrioventricular nodal cells, accounting for the observed heart block. Trpm7 is dispensable in adult ventricular myocardium under basal conditions but is critical for myocardial proliferation during early cardiogenesis. Loss of Trpm7 at an intermediate developmental time point alters the myocardial transcriptional profile in adulthood, impairing ventricular function, conduction, and repolarization.

A universal procedure for evaluation and application of surge-protective devices

NASA Technical Reports Server (NTRS)

1980-01-01

The source, nature, and frequency of occurrence of transients must be identified and a representative standard test wave chosen for proof testing. The performance of candidate suppressor devices then can be evaluated against the withstand goals set for the equipment. The various suppressors divide into two classes of generic behavior. The key to a universal procedure for evaluating both classes lies in representing transients as quasi-current sources of defined current impulse duration. The available surge current is established by the Thevenin equivalent transient voltage and source impedance. A load line drawn on the V-I characteristic graph of the suppressor quickly determines the clamping voltage and peak current. These values then can be compared to the requirement. The deposited energy and average power dissipation for multiple transients also can be calculated. The method is illustrated with a design example for motor vehicle alternator load dump suppression.

Turbofan compressor dynamics during afterburner transients

NASA Technical Reports Server (NTRS)

Kurkov, A. P.

1975-01-01

The effects of afterburner light-off and shut-down transients on compressor stability were investigated. Experimental results are based on detailed high-response pressure and temperature measurements on the Tf30-p-3 turbofan engine. The tests were performed in an altitude test chamber simulating high-altitude engine operation. It is shown that during both types of transients, flow breaks down in the forward part of the fan-bypass duct. At a sufficiently low engine inlet pressure this resulted in a compressor stall. Complete flow breakdown within the compressor was preceded by a rotating stall. At some locations in the compressor, rotating stall cells initially extended only through part of the blade span. For the shutdown transient, the time between first and last detected occurrence of rotating stall is related to the flow Reynolds number. An attempt was made to deduce the number and speed of propagation of rotating stall cells.

The advantages and disadvantages of using the TREAT reactor for nuclear laser experiments

NASA Astrophysics Data System (ADS)

Dickson, P. W.; Snyder, A. M.; Imel, G. R.; McConnell, R. J.

The Transient Reactor Test Facility (TREAT) is a large air-cooled test facility located at the Idaho National Engineering Laboratory. Two of the major design features of TREAT, its large size and its being an air-cooled reactor, provide clues to both its advantages and disadvantages for supporting nuclear laser experiments. Its large size, which is dictated by the dilute uranium/graphite fuel, permits accommodation of geometrically large experiments. However, TREAT's large size also results in relatively long transients so that the energy deposited in an experiment is large relative to the peak power available from the reactor. TREAT's air-cooling mode of operation allows its configuration to be changed fairly readily. Due to air cooling, the reactor cools down slowly, permitting only one full power transient a day, which can be a disadvantage in some experimental programs. The reactor is capable of both steady-state or transient operation.

Transient receptor potential channel superfamily: Role in lower urinary tract function.

PubMed

Ogawa, Teruyuki; Imamura, Tetsuya; Nakazawa, Masaki; Hiragata, Shiro; Nagai, Takashi; Minagawa, Tomonori; Yokoyama, Hitoshi; Ishikawa, Masakuni; Domen, Takahisa; Ishizuka, Osamu

2015-11-01

Lower urinary tract symptoms associated with neurogenic bladder and overactive bladder syndrome are mediated in part by members of the transient receptor potential channel superfamily. The best studied member of this superfamily is the vanilloid receptor. Other transient receptor potential channels, such as the melastatin receptor and the ankyrin receptor, are also active in the pathogenesis of lower urinary tract dysfunction. However, the detailed mechanisms by which the transient receptor potential channels contribute to lower urinary tract symptoms are still not clear, and the therapeutic benefits of modulating transient receptor potential channel activity have not been proved in the clinical setting. In the present review, to better understand the pathophysiology and therapeutic potential for lower urinary tract symptoms, we summarize the presence and role of different members of the transient receptor potential channel superfamily in the lower urinary tract. © 2015 The Japanese Urological Association.

Operation Sun Beam, Shot Small Boy. Project Officer's report - Project 7. 8. Arming and fuzing component test

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

Taslitt, N.

1985-09-01

The objectives of this project were to (1) determine whether the radiation from a nuclear weapon can disable various arming and fuzing components by causing permanent damage; (2) determine whether transient nuclear radiation can induce an operating fuze to malfunction; and (3) compare nuclear weapon radiation effects with those produced by various radiation simulators. Data obtained revealed that none of the inertial components were detrimentally affected. The electronic components were severely degraded but would have satisfactorily accomplished their tactical functions. No electromagnetic effects were detected.

Design and evaluation of an electrohydraulic servoactuator using active standby redundancy

NASA Technical Reports Server (NTRS)

Anderson, R. L.; Cover, W. E.

1972-01-01

The application is described of active standby redundancy techniques to a large electrohydraulic servoactuator. The advantages and limitations of active standby redundancy are identified. Special areas of investigation during the development test phase of the program were the evaluation of output transients as a function of channel switching and the nuisance switching characteristics of the system. The feasibility of constructing large electrohydraulic servoactuators using active standby redundancy was successfully demonstrated. In particular the stability and predictability of a properly designed hydromechanical failure detector was demonstrated.

Robotic exoskeleton assessment of transient ischemic attack.

PubMed

Simmatis, Leif; Krett, Jonathan; Scott, Stephen H; Jin, Albert Y

2017-01-01

We used a robotic exoskeleton to quantify specific patterns of abnormal upper limb motor behaviour in people who have had transient ischemic attack (TIA). A cohort of people with TIA was recruited within two weeks of symptom onset. All individuals completed a robotic-based assessment of 8 behavioural tasks related to upper limb motor and proprioceptive function, as well as cognitive function. Robotic task performance was compared to a large cohort of controls without neurological impairments corrected for the influence of age. Impairment in people with TIA was defined as performance below the 5th percentile of controls. Participants with TIA were also assessed with the National Institutes of Health Stroke Scale (NIHSS) score, Chedoke-McMaster Stroke Assessment (CMSA) of the arm, the Behavioural Inattention Test (BIT), the Purdue pegboard test (PPB), and the Montreal Cognitive Assessment (MoCA). Age-related white matter change (ARWMC), prior infarction and cella-media index (CMI) were assessed from baseline CT scan that was performed within 24 hours of TIA. Acute infarction was assessed from diffusion-weighted imaging in a subset of people with TIA. Twenty-two people with TIA were assessed. Robotic assessment showed impaired upper limb motor function in 7/22 people with TIA patients and upper limb sensory impairment in 4/22 individuals. Cognitive tasks involving robotic assessment of the upper limb were completed in 13 participants, of whom 8 (61.5%) showed significant impairment. Abnormal performance in the CMSA arm inventory was present in 12/22 (54.5%) participants. ARWMC was 11.8 ± 6.4 and CMI was 5.4 ± 1.5. DWI was positive in 0 participants. Quantitative robotic assessment showed that people who have had a TIA display a spectrum of upper limb motor and sensory performance deficits as well as cognitive function deficits despite resolution of symptoms and no evidence of tissue infarction.

Transient Modeling of Hybrid Rocket Low Frequency Instabilities

NASA Technical Reports Server (NTRS)

Karabeyoglu, M. Arif; DeZilwa, Shane; Cantwell, Brian; Zilliac, Greg

2003-01-01

A comprehensive dynamic model of a hybrid rocket has been developed in order to understand and predict the transient behavior including instabilities. A linearized version of the transient model predicted the low-frequency chamber pressure oscillations that are commonly observed in hybrids. The source of the instabilities is based on a complex coupling of thermal transients in the solid fuel, wall heat transfer blocking due to fuel regression rate and the transients in the boundary layer that forms on the fuel surface. The oscillation frequencies predicted by the linearized theory are in very good agreement with 43 motor test results obtained from the hybrid propulsion literature. The motor test results used in the comparison cover a very wide spectrum of parameters including: 1) four separate research and development programs, 2) three different oxidizers (LOX, GOX, N2O), 3) a wide range of motor dimensions (i.e. from 5 inch diameter to 72 inch diameter) and operating conditions and 4) several fuel formulations. A simple universal scaling formula for the frequency of the primary oscillation mode is suggested.

Parameter Transient Behavior Analysis on Fault Tolerant Control System

NASA Technical Reports Server (NTRS)

Belcastro, Christine (Technical Monitor); Shin, Jong-Yeob

2003-01-01

In a fault tolerant control (FTC) system, a parameter varying FTC law is reconfigured based on fault parameters estimated by fault detection and isolation (FDI) modules. FDI modules require some time to detect fault occurrences in aero-vehicle dynamics. This paper illustrates analysis of a FTC system based on estimated fault parameter transient behavior which may include false fault detections during a short time interval. Using Lyapunov function analysis, the upper bound of an induced-L2 norm of the FTC system performance is calculated as a function of a fault detection time and the exponential decay rate of the Lyapunov function.

A new transiently chaotic flow with ellipsoid equilibria

NASA Astrophysics Data System (ADS)

Panahi, Shirin; Aram, Zainab; Jafari, Sajad; Pham, Viet-Thanh; Volos, Christos; Rajagopal, Karthikeyan

2018-03-01

In this article, a simple autonomous transiently chaotic flow with cubic nonlinearities is proposed. This system represents some unusual features such as having a surface of equilibria. We shall describe some dynamical properties and behaviours of this system in terms of eigenvalue structures, bifurcation diagrams, time series, and phase portraits. Various behaviours of this system such as periodic and transiently chaotic dynamics can be shown by setting special parameters in proper values. Our system belongs to a newly introduced category of transiently chaotic systems: systems with hidden attractors. Transiently chaotic behaviour of our proposed system has been implemented and tested by the OrCAD-PSpise software. We have found a proper qualitative similarity between circuit and simulation results.

Large liquid rocket engine transient performance simulation system

NASA Technical Reports Server (NTRS)

Mason, J. R.; Southwick, R. D.

1989-01-01

Phase 1 of the Rocket Engine Transient Simulation (ROCETS) program consists of seven technical tasks: architecture; system requirements; component and submodel requirements; submodel implementation; component implementation; submodel testing and verification; and subsystem testing and verification. These tasks were completed. Phase 2 of ROCETS consists of two technical tasks: Technology Test Bed Engine (TTBE) model data generation; and system testing verification. During this period specific coding of the system processors was begun and the engineering representations of Phase 1 were expanded to produce a simple model of the TTBE. As the code was completed, some minor modifications to the system architecture centering on the global variable common, GLOBVAR, were necessary to increase processor efficiency. The engineering modules completed during Phase 2 are listed: INJTOO - main injector; MCHBOO - main chamber; NOZLOO - nozzle thrust calculations; PBRNOO - preburner; PIPE02 - compressible flow without inertia; PUMPOO - polytropic pump; ROTROO - rotor torque balance/speed derivative; and TURBOO - turbine. Detailed documentation of these modules is in the Appendix. In addition to the engineering modules, several submodules were also completed. These submodules include combustion properties, component performance characteristics (maps), and specific utilities. Specific coding was begun on the system configuration processor. All functions necessary for multiple module operation were completed but the SOLVER implementation is still under development. This system, the Verification Checkout Facility (VCF) allows interactive comparison of module results to store data as well as provides an intermediate checkout of the processor code. After validation using the VCF, the engineering modules and submodules were used to build a simple TTBE.

Waterhammer Transient Simulation and Model Anchoring for the Robotic Lunar Lander Propulsion System

NASA Technical Reports Server (NTRS)

Stein, William B.; Trinh, Huu P.; Reynolds, Michael E.; Sharp, David J.

2011-01-01

Waterhammer transients have the potential to adversely impact propulsion system design if not properly addressed. Waterhammer can potentially lead to system plumbing, and component damage. Multi-thruster propulsion systems also develop constructive/destructive wave interference which becomes difficult to predict without detailed models. Therefore, it is important to sufficiently characterize propulsion system waterhammer in order to develop a robust design with minimal impact to other systems. A risk reduction activity was performed at Marshall Space Flight Center to develop a tool for estimating waterhammer through the use of anchored simulation for the Robotic Lunar Lander (RLL) propulsion system design. Testing was performed to simulate waterhammer surges due to rapid valve closure and consisted of twenty-two series of waterhammer tests, resulting in more than 300 valve actuations. These tests were performed using different valve actuation schemes and three system pressures. Data from the valve characterization tests were used to anchor the models that employed MSCSoftware.EASY5 v.2010 to model transient fluid phenomena by using transient forms of mass and energy conservation. The anchoring process was performed by comparing initial model results to experimental data and then iterating the model input to match the simulation results with the experimental data. The models provide good correlation with experimental results, supporting the use of EASY5 as a tool to model fluid transients and provide a baseline for future RLL system modeling. This paper addresses tasks performed during the waterhammer risk reduction activity for the RLL propulsion system. The problem of waterhammer simulation anchoring as applied to the RLL system is discussed with results from the corresponding experimental valve tests. Important factors for waterhammer mitigation are discussed along with potential design impacts to the RLL propulsion system.

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

Espinosa-Paredes, Gilberto; Prieto-Guerrero, Alfonso; Nunez-Carrera, Alejandro

This paper introduces a wavelet-based method to analyze instability events in a boiling water reactor (BWR) during transient phenomena. The methodology to analyze BWR signals includes the following: (a) the short-time Fourier transform (STFT) analysis, (b) decomposition using the continuous wavelet transform (CWT), and (c) application of multiresolution analysis (MRA) using discrete wavelet transform (DWT). STFT analysis permits the study, in time, of the spectral content of analyzed signals. The CWT provides information about ruptures, discontinuities, and fractal behavior. To detect these important features in the signal, a mother wavelet has to be chosen and applied at several scales tomore » obtain optimum results. MRA allows fast implementation of the DWT. Features like important frequencies, discontinuities, and transients can be detected with analysis at different levels of detail coefficients. The STFT was used to provide a comparison between a classic method and the wavelet-based method. The damping ratio, which is an important stability parameter, was calculated as a function of time. The transient behavior can be detected by analyzing the maximum contained in detail coefficients at different levels in the signal decomposition. This method allows analysis of both stationary signals and highly nonstationary signals in the timescale plane. This methodology has been tested with the benchmark power instability event of Laguna Verde nuclear power plant (NPP) Unit 1, which is a BWR-5 NPP.« less

Pretest predictions of the Fast Flux Test Facility Passive Safety Test Phase IIB transients using United States derived computer codes and methods

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

Heard, F.J.; Harris, R.A.; Padilla, A.

The SASSYS/SAS4A systems analysis code was used to simulate a series of unprotected loss of flow (ULOF) tests planned at the Fast Flux Test Facility (FFTF). The subject tests were designed to investigate the transient performance of the FFTF during various ULOF scenarios for two different loading patterns designed to produce extremes in the assembly load pad clearance and the direction of the initial assembly bows. The tests are part of an international program designed to extend the existing data base on the performance of liquid metal reactors (LMR). The analyses demonstrate that a wide range of power-to-flow ratios canmore » be reached during the transients and, therefore, will yield valuable data on the dynamic character of the structural feedbacks in LMRS. These analyses will be repeated once the actual FFTF core loadings for the tests are available. These predictions, similar ones obtained by other international participants in the FFTF program, and post-test analyses will be used to upgrade and further verify the computer codes used to predict the behavior of LMRS.« less

Revealing transient strain in geodetic data with Gaussian process regression

NASA Astrophysics Data System (ADS)

Hines, T. T.; Hetland, E. A.

2018-03-01

Transient strain derived from global navigation satellite system (GNSS) data can be used to detect and understand geophysical processes such as slow slip events and post-seismic deformation. Here we propose using Gaussian process regression (GPR) as a tool for estimating transient strain from GNSS data. GPR is a non-parametric, Bayesian method for interpolating scattered data. In our approach, we assume a stochastic prior model for transient displacements. The prior describes how much we expect transient displacements to covary spatially and temporally. A posterior estimate of transient strain is obtained by differentiating the posterior transient displacements, which are formed by conditioning the prior with the GNSS data. As a demonstration, we use GPR to detect transient strain resulting from slow slip events in the Pacific Northwest. Maximum likelihood methods are used to constrain a prior model for transient displacements in this region. The temporal covariance of our prior model is described by a compact Wendland covariance function, which significantly reduces the computational burden that can be associated with GPR. Our results reveal the spatial and temporal evolution of strain from slow slip events. We verify that the transient strain estimated with GPR is in fact geophysical signal by comparing it to the seismic tremor that is associated with Pacific Northwest slow slip events.

Ultrafast triggered transient energy storage by atomic layer deposition into porous silicon for integrated transient electronics

NASA Astrophysics Data System (ADS)

Douglas, Anna; Muralidharan, Nitin; Carter, Rachel; Share, Keith; Pint, Cary L.

2016-03-01

Here we demonstrate the first on-chip silicon-integrated rechargeable transient power source based on atomic layer deposition (ALD) coating of vanadium oxide (VOx) into porous silicon. A stable specific capacitance above 20 F g-1 is achieved until the device is triggered with alkaline solutions. Due to the rational design of the active VOx coating enabled by ALD, transience occurs through a rapid disabling step that occurs within seconds, followed by full dissolution of all active materials within 30 minutes of the initial trigger. This work demonstrates how engineered materials for energy storage can provide a basis for next-generation transient systems and highlights porous silicon as a versatile scaffold to integrate transient energy storage into transient electronics.Here we demonstrate the first on-chip silicon-integrated rechargeable transient power source based on atomic layer deposition (ALD) coating of vanadium oxide (VOx) into porous silicon. A stable specific capacitance above 20 F g-1 is achieved until the device is triggered with alkaline solutions. Due to the rational design of the active VOx coating enabled by ALD, transience occurs through a rapid disabling step that occurs within seconds, followed by full dissolution of all active materials within 30 minutes of the initial trigger. This work demonstrates how engineered materials for energy storage can provide a basis for next-generation transient systems and highlights porous silicon as a versatile scaffold to integrate transient energy storage into transient electronics. Electronic supplementary information (ESI) available: (i) Experimental details for ALD and material fabrication, ellipsometry film thickness, preparation of gel electrolyte and separator, details for electrochemical measurements, HRTEM image of VOx coated porous silicon, Raman spectroscopy for VOx as-deposited as well as annealed in air for 1 hour at 450 °C, SEM and transient behavior dissolution tests of uniformly coated VOx on porous silicon, dissolution tests for 0.1 M and 0.01 M NaOH trigger solutions, EIS analysis for VOx coated devices, and EDS compositional analysis of VOx. (ii) Video showing transient behavior of integrated VOx/porous silicon scaffolds. See DOI: 10.1039/c5nr09095d

Efficacy and safety of chloral hydrate sedation in infants for pulmonary function tests.

PubMed

Wandalsen, Gustavo Falbo; Lanza, Fernanda de Cordoba; Nogueira, Márcia Cristina Pires; Solé, Dirceu

2016-12-01

To describe the efficacy and safety of chloral hydrate sedation in infants for pulmonary function tests. All sedation attempts for pulmonary function tests in infants carried out between June 2007 and August 2014 were evaluated. Obstructive sleep apnea and heart disease were contraindications to the exams. Anthropometric data, exam indication, used dose, outcomes of sedation and clinical events were recorded and described. The sedation attempts in 277 infants (165 boys) with a median age of 51.5 weeks of life (14 to 182 weeks) were evaluated. The main indication for the tests was recurrent wheezing (56%) and the chloral hydrate dose ranged from 50 to 80mg/kg (orally). Eighteen (6.5%) infants had some type of clinical complication, with the most frequent being cough and/or airway secretion (1.8%); respiratory distress (1.4%) and vomiting (1.1%). A preterm infant had bradycardia for approximately 15 minutes, which was responsive to tactile stimulation. All observed adverse effects were transient and there was no need for resuscitation or use of injectable medications. The data demonstrated that chloral hydrate at the employed doses is a safe and effective medicament for sedation during short procedures in infants, such as pulmonary function tests. Because of the possibility of severe adverse events, recommendations on doses and contraindications should be strictly followed and infants should be monitored by trained staff. Copyright © 2016 Sociedade de Pediatria de São Paulo. Publicado por Elsevier Editora Ltda. All rights reserved.

Auditory dysfunction associated with solvent exposure

PubMed Central

2013-01-01

Background A number of studies have demonstrated that solvents may induce auditory dysfunction. However, there is still little knowledge regarding the main signs and symptoms of solvent-induced hearing loss (SIHL). The aim of this research was to investigate the association between solvent exposure and adverse effects on peripheral and central auditory functioning with a comprehensive audiological test battery. Methods Seventy-two solvent-exposed workers and 72 non-exposed workers were selected to participate in the study. The test battery comprised pure-tone audiometry (PTA), transient evoked otoacoustic emissions (TEOAE), Random Gap Detection (RGD) and Hearing-in-Noise test (HINT). Results Solvent-exposed subjects presented with poorer mean test results than non-exposed subjects. A bivariate and multivariate linear regression model analysis was performed. One model for each auditory outcome (PTA, TEOAE, RGD and HINT) was independently constructed. For all of the models solvent exposure was significantly associated with the auditory outcome. Age also appeared significantly associated with some auditory outcomes. Conclusions This study provides further evidence of the possible adverse effect of solvents on the peripheral and central auditory functioning. A discussion of these effects and the utility of selected hearing tests to assess SIHL is addressed. PMID:23324255

Proper Image Subtraction—Optimal Transient Detection, Photometry, and Hypothesis Testing

NASA Astrophysics Data System (ADS)

Zackay, Barak; Ofek, Eran O.; Gal-Yam, Avishay

2016-10-01

Transient detection and flux measurement via image subtraction stand at the base of time domain astronomy. Due to the varying seeing conditions, the image subtraction process is non-trivial, and existing solutions suffer from a variety of problems. Starting from basic statistical principles, we develop the optimal statistic for transient detection, flux measurement, and any image-difference hypothesis testing. We derive a closed-form statistic that: (1) is mathematically proven to be the optimal transient detection statistic in the limit of background-dominated noise, (2) is numerically stable, (3) for accurately registered, adequately sampled images, does not leave subtraction or deconvolution artifacts, (4) allows automatic transient detection to the theoretical sensitivity limit by providing credible detection significance, (5) has uncorrelated white noise, (6) is a sufficient statistic for any further statistical test on the difference image, and, in particular, allows us to distinguish particle hits and other image artifacts from real transients, (7) is symmetric to the exchange of the new and reference images, (8) is at least an order of magnitude faster to compute than some popular methods, and (9) is straightforward to implement. Furthermore, we present extensions of this method that make it resilient to registration errors, color-refraction errors, and any noise source that can be modeled. In addition, we show that the optimal way to prepare a reference image is the proper image coaddition presented in Zackay & Ofek. We demonstrate this method on simulated data and real observations from the PTF data release 2. We provide an implementation of this algorithm in MATLAB and Python.

Performance testing of lidar receivers

NASA Technical Reports Server (NTRS)

Shams, M. Y.

1986-01-01

In addition to the considerations about the different types of noise sources, dynamic range, and linearity of a lidar receiver, one requires information about the pulse shape retaining capabilities of the receiver. For this purpose, relatively precise information about the height resolution as well as the recovery time of the receiver, due both to large transients and to fast changes in the received signal, is required. As more and more analog receivers using fast analog to digital converters and transient recorders will be used in the future lidar systems, methods to test these devices are essential. The method proposed for this purpose is shown. Tests were carried out using LCW-10, LT-20, and FTVR-2 as optical parts of the optical pulse generator circuits. A commercial optical receiver, LNOR, and a transient recorder, VK 220-4, were parts of the receiver system.

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

Savich, A. I.; Bugaevskii, A. G., E-mail: office@geodyn.ru, E-mail: bugaevskiy@geodyn.ru

Functional dependencies are established for the characteristics of seismic transients recorded at various points of a studied site, which are used to propose a new approach to seismic microzonation (SMZ) that enables the creation of new SMZ maps of strong seismic motion, with due regard for dynamic parameters of recorded transients during weak earthquakes.

CIRCUS--A digital computer program for transient analysis of electronic circuits

NASA Technical Reports Server (NTRS)

Moore, W. T.; Steinbert, L. L.

1968-01-01

Computer program simulates the time domain response of an electronic circuit to an arbitrary forcing function. CIRCUS uses a charge-control parameter model to represent each semiconductor device. Given the primary photocurrent, the transient behavior of a circuit in a radiation environment is determined.

Nuclei-mode particulate emissions and their response to fuel sulfur content and primary dilution during transient operations of old and modern diesel engines.

PubMed

Liu, Z Gerald; Vasys, Victoria N; Kittelson, David B

2007-09-15

The effects of fuel sulfur content and primary dilution on PM number emissions were investigated during transient operations of an old and a modern diesel engine. Emissions were also studied during steady-state operations in order to confirm consistency with previous findings. Testing methods were concurrent with those implemented by the EPA to regulate PM mass emissions, including the use of the Federal Transient Testing Procedure-Heavy Duty cycle to simulate transient conditions and the use of a Critical Flow Venturi-Constant Volume System to provide primary dilution. Steady-state results were found to be consistent with previous studies in that nuclei-mode particulate emissions were largely reduced when lower-sulfur content fuel was used in the newer engine, while the nuclei-mode PM emissions from the older engine were much less affected by fuel sulfur content. The transient results, however, show that the total number of nuclei-mode PM emissions from both engines increases with fuel sulfur content, although this effect is only seen under the higher primary dilution ratios with the older engine. Transient results further show that higher primary dilution ratios increase total nuclei-mode PM number emissions in both engines.

Preliminary Results for the OECD/NEA Time Dependent Benchmark using Rattlesnake, Rattlesnake-IQS and TDKENO

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

DeHart, Mark D.; Mausolff, Zander; Weems, Zach

2016-08-01

One goal of the MAMMOTH M&S project is to validate the analysis capabilities within MAMMOTH. Historical data has shown limited value for validation of full three-dimensional (3D) multi-physics methods. Initial analysis considered the TREAT startup minimum critical core and one of the startup transient tests. At present, validation is focusing on measurements taken during the M8CAL test calibration series. These exercises will valuable in preliminary assessment of the ability of MAMMOTH to perform coupled multi-physics calculations; calculations performed to date are being used to validate the neutron transport solver Rattlesnake\\cite{Rattlesnake} and the fuels performance code BISON. Other validation projects outsidemore » of TREAT are available for single-physics benchmarking. Because the transient solution capability of Rattlesnake is one of the key attributes that makes it unique for TREAT transient simulations, validation of the transient solution of Rattlesnake using other time dependent kinetics benchmarks has considerable value. The Nuclear Energy Agency (NEA) of the Organization for Economic Cooperation and Development (OECD) has recently developed a computational benchmark for transient simulations. This benchmark considered both two-dimensional (2D) and 3D configurations for a total number of 26 different transients. All are negative reactivity insertions, typically returning to the critical state after some time.« less

Transient vibration analytical modeling and suppressing for vibration absorber system under impulse excitation

NASA Astrophysics Data System (ADS)

Wang, Xi; Yang, Bintang; Yu, Hu; Gao, Yulong

2017-04-01

The impulse excitation of mechanism causes transient vibration. In order to achieve adaptive transient vibration control, a method which can exactly model the response need to be proposed. This paper presents an analytical model to obtain the response of the primary system attached with dynamic vibration absorber (DVA) under impulse excitation. The impulse excitation which can be divided into single-impulse excitation and multi-impulse excitation is simplified as sinusoidal wave to establish the analytical model. To decouple the differential governing equations, a transform matrix is applied to convert the response from the physical coordinate to model coordinate. Therefore, the analytical response in the physical coordinate can be obtained by inverse transformation. The numerical Runge-Kutta method and experimental tests have demonstrated the effectiveness of the analytical model proposed. The wavelet of the response indicates that the transient vibration consists of components with multiple frequencies, and it shows that the modeling results coincide with the experiments. The optimizing simulations based on genetic algorithm and experimental tests demonstrate that the transient vibration of the primary system can be decreased by changing the stiffness of the DVA. The results presented in this paper are the foundations for us to develop the adaptive transient vibration absorber in the future.

Muscular exercise can cause highly pathological liver function tests in healthy men

PubMed Central

Pettersson, Jonas; Hindorf, Ulf; Persson, Paula; Bengtsson, Thomas; Malmqvist, Ulf; Werkström, Viktoria; Ekelund, Mats

2008-01-01

Aim To investigate the effect of intensive muscular exercise (weightlifting) on clinical chemistry parameters reflecting liver function in healthy men. Methods Fifteen healthy men, used to moderate physical activity not including weightlifting, performed an 1 h long weightlifting programme. Blood was sampled for clinical chemistry parameters [aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LD), gamma-glutamyl transferase (γGT), alkaline phosphatase (ALP), bilirubin, creatine kinase (CK) and myoglobin] at repeated intervals during 7 days postexercise and at a follow-up examination 10–12 days postexercise. Results Five out of eight studied clinical chemistry parameters (AST, ALT, LD, CK and myoglobin) increased significantly after exercise (P < 0.01) and remained increased for at least 7 days postexercise. Bilirubin, γGT and ALP remained within the normal range. Conclusion The liver function parameters, AST and ALT, were significantly increased for at least 7 days after the exercise. In addition, LD and, in particular, CK and myoglobin showed highly elevated levels. These findings highlight the importance of imposing restrictions on weightlifting prior to and during clinical studies. Intensive muscular exercise, e.g. weightlifting, should also be considered as a cause of asymptomatic elevations of liver function tests in daily clinical practice. What is already known about this subject The occurrence of idiosyncratic drug hepatotoxicity is a major problem in all phases of clinical drug development and the leading cause of postmarketing warnings and withdrawals.Physical exercise can result in transient elevations of liver function tests.There is no consensus in the literature on which forms of exercise may cause changes in liver function tests and to what extent. What this study adds Weightlifting results in profound increases in liver function tests in healthy men used to moderate physical activity, not including weightlifting.Liver function tests are significantly increased for at least 7 days after weightlifting.It is important to impose relevant restrictions on heavy muscular exercise prior to and during clinical studies. PMID:17764474

Muscular exercise can cause highly pathological liver function tests in healthy men.

PubMed

Pettersson, Jonas; Hindorf, Ulf; Persson, Paula; Bengtsson, Thomas; Malmqvist, Ulf; Werkström, Viktoria; Ekelund, Mats

2008-02-01

The occurrence of idiosyncratic drug hepatotoxicity is a major problem in all phases of clinical drug development and the leading cause of postmarketing warnings and withdrawals. Physical exercise can result in transient elevations of liver function tests. There is no consensus in the literature on which forms of exercise may cause changes in liver function tests and to what extent. Weightlifting results in profound increases in liver function tests in healthy men used to moderate physical activity, not including weightlifting. Liver function tests are significantly increased for at least 7 days after weightlifting. It is important to impose relevant restrictions on heavy muscular exercise prior to and during clinical studies. To investigate the effect of intensive muscular exercise (weightlifting) on clinical chemistry parameters reflecting liver function in healthy men. Fifteen healthy men, used to moderate physical activity not including weightlifting, performed an 1 h long weightlifting programme. Blood was sampled for clinical chemistry parameters [aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LD), gamma-glutamyl transferase (gamma GT), alkaline phosphatase (ALP), bilirubin, creatine kinase (CK) and myoglobin] at repeated intervals during 7 days postexercise and at a follow-up examination 10-12 days postexercise. Five out of eight studied clinical chemistry parameters (AST, ALT, LD, CK and myoglobin) increased significantly after exercise (P < 0.01) and remained increased for at least 7 days postexercise. Bilirubin, gamma GT and ALP remained within the normal range. The liver function parameters, AST and ALT, were significantly increased for at least 7 days after the exercise. In addition, LD and, in particular, CK and myoglobin showed highly elevated levels. These findings highlight the importance of imposing restrictions on weightlifting prior to and during clinical studies. Intensive muscular exercise, e.g. weightlifting, should also be considered as a cause of asymptomatic elevations of liver function tests in daily clinical practice.

Actively controlled shaft seals for aerospace applications

NASA Technical Reports Server (NTRS)

Salant, Richard F.

1993-01-01

An electronically controlled mechanical seal for use as the purge gas seal in a liquid oxygen turbo pump has been fabricated and tested under transient operating conditions. The thickness of the lubricating film is controlled by adjusting the coning of the carbon face. This is accomplished by applying a voltage to a piezoelectric actuator to which the carbon face is bonded. The seal has been operated with a closed-loop control system that utilizes either the leakage rate or the seal face temperature as the feedback. Both speed and pressure transients have been imposed on the seal. The transient tests have demonstrated that the seal is capable of maintaining low leakage rates while limiting the face temperatures.

Design criteria for a self-actuated shutdown system to ensure limitation of core damage. [LMFBR

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

Deane, N.A.; Atcheson, D.B.

1981-09-01

Safety-based functional requirements and design criteria for a self-actuated shutdown system (SASS) are derived in accordance with LOA-2 success criteria and reliability goals. The design basis transients have been defined and evaluated for the CDS Phase II design, which is a 2550 MWt mixed oxide heterogeneous core reactor. A partial set of reactor responses for selected transients is provided as a function of SASS characteristics such as reactivity worth, trip points, and insertion times.

The use of Lyapunov differential inequalities for estimating the transients of mechanical systems

NASA Astrophysics Data System (ADS)

Alyshev, A. S.; Dudarenko, N. A.; Melnikov, V. G.; Melnikov, G. I.

2018-05-01

In this paper we consider an autonomous mechanical system in a finite neighborhood of the zero of the phase space of states. The system is given as a matrix differential equation in the Cauchy form with the right-hand side of the polynomial structure. We propose a method for constructing a sequence of linear inhomogeneous differential inequalities for Lyapunov functions. As a result, we obtain estimates of transient processes in the form of functional inequalities.

Parametric Thermal Models of the Transient Reactor Test Facility (TREAT)

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

Bradley K. Heath

2014-03-01

This work supports the restart of transient testing in the United States using the Department of Energy’s Transient Reactor Test Facility at the Idaho National Laboratory. It also supports the Global Threat Reduction Initiative by reducing proliferation risk of high enriched uranium fuel. The work involves the creation of a nuclear fuel assembly model using the fuel performance code known as BISON. The model simulates the thermal behavior of a nuclear fuel assembly during steady state and transient operational modes. Additional models of the same geometry but differing material properties are created to perform parametric studies. The results show thatmore » fuel and cladding thermal conductivity have the greatest effect on fuel temperature under the steady state operational mode. Fuel density and fuel specific heat have the greatest effect for transient operational model. When considering a new fuel type it is recommended to use materials that decrease the specific heat of the fuel and the thermal conductivity of the fuel’s cladding in order to deal with higher density fuels that accompany the LEU conversion process. Data on the latest operating conditions of TREAT need to be attained in order to validate BISON’s results. BISON’s models for TREAT (material models, boundary convection models) are modest and need additional work to ensure accuracy and confidence in results.« less

Object-oriented approach for gas turbine engine simulation

NASA Technical Reports Server (NTRS)

Curlett, Brian P.; Felder, James L.

1995-01-01

An object-oriented gas turbine engine simulation program was developed. This program is a prototype for a more complete, commercial grade engine performance program now being proposed as part of the Numerical Propulsion System Simulator (NPSS). This report discusses architectural issues of this complex software system and the lessons learned from developing the prototype code. The prototype code is a fully functional, general purpose engine simulation program, however, only the component models necessary to model a transient compressor test rig have been written. The production system will be capable of steady state and transient modeling of almost any turbine engine configuration. Chief among the architectural considerations for this code was the framework in which the various software modules will interact. These modules include the equation solver, simulation code, data model, event handler, and user interface. Also documented in this report is the component based design of the simulation module and the inter-component communication paradigm. Object class hierarchies for some of the code modules are given.

The dynamic-response characteristics of a 35 degree swept-wing airplane as determined from flight measurements

NASA Technical Reports Server (NTRS)

Triplett, William C; Brown, Stuart C; Smith, G Allan

1955-01-01

The longitudinal and lateral-directional dynamic-response characteristics of a 35 degree swept-wing fighter-type airplane determined from flight measurements are presented and compared with predictions based on theoretical studies and wind-tunnel data. Flights were made at an altitude of 35,000 feet covering the Mach number range of 0.50 to 1.04. A limited amount of lateral-directional data were also obtained at 10,000 feet. The flight consisted essentially of recording transient responses to pilot-applied pulsed motions of each of the three primary control surfaces. These transient data were converted into frequency-response form by means of the Fourier transformation and compared with predicted responses calculated from the basic equations. Experimentally determined transfer functions were used for the evaluation of the stability derivatives that have the greatest effect on the dynamic response of the airplane. The values of these derivatives, in most cases, agreed favorably with predictions over the Mach number range of the test.

Measurement of transient gas flow parameters by diode laser absorption spectroscopy

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

Bolshov, M A; Kuritsyn, Yu A; Liger, V V

2015-04-30

An absorption spectrometer based on diode lasers is developed for measuring two-dimension maps of temperature and water vapour concentration distributions in the combustion zones of two mixing supersonic flows of fuel and oxidiser in the single run regime. The method of measuring parameters of hot combustion zones is based on detection of transient spectra of water vapour absorption. The design of the spectrometer considerably reduces the influence of water vapour absorption along the path of a sensing laser beam outside the burning chamber. The optical scheme is developed, capable of matching measurement results in different runs of mixture burning. Amore » new algorithm is suggested for obtaining information about the mixture temperature by constructing the correlation functions of the experimental spectrum with those simulated from databases. A two-dimensional map of temperature distribution in a test chamber is obtained for the first time under the conditions of plasma-induced combusion of the ethylene – air mixture. (laser applications and other topics in quantum electronics)« less

Analytical model for atomic resonant attosecond transient absorption

NASA Astrophysics Data System (ADS)

Cariker, C.; Kjellson, T.; Lindroth, E.; Argenti, L.

2017-04-01

Recent advancements in ultrafast laser technology have made it possible to probe electron dynamics in highly excited atomic states that autoionize on a femtosecond timescale, thus giving insight into the dynamics of Auger decay and its interference with the continuum. These experiments provide a stringent test for time-resolved analytical models of autoionization. Here we present a finite-pulse, multi-photon perturbative model which is used in conjunction with ab-initio structure calculations to predict the attosecond transient absorption spectrum (ATAS) of an atom above the ionization threshold. We apply this model to compute the ATAS of argon in the vicinity of the 3s-1 4 p resonance as a function of the time delay between an extreme ultraviolet (XUV) and an infrared (IR) pulse, as well as of the angle between their polarization. We show that by modulating the parameters of the IR pulse it is possible to control the dipolar coupling between neighboring states and hence the lineshape of the 3s-1 4 p resonance. NSF Grant No. 1607588.

Modification of the SAS4A Safety Analysis Code for Integration with the ADAPT Discrete Dynamic Event Tree Framework.

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

Jankovsky, Zachary Kyle; Denman, Matthew R.

It is difficult to assess the consequences of a transient in a sodium-cooled fast reactor (SFR) using traditional probabilistic risk assessment (PRA) methods, as numerous safety-related sys- tems have passive characteristics. Often there is significant dependence on the value of con- tinuous stochastic parameters rather than binary success/failure determinations. One form of dynamic PRA uses a system simulator to represent the progression of a transient, tracking events through time in a discrete dynamic event tree (DDET). In order to function in a DDET environment, a simulator must have characteristics that make it amenable to changing physical parameters midway through themore » analysis. The SAS4A SFR system analysis code did not have these characteristics as received. This report describes the code modifications made to allow dynamic operation as well as the linking to a Sandia DDET driver code. A test case is briefly described to demonstrate the utility of the changes.« less

[Neonatal diabetes mellitus and KCNJ11 gene mutation: report of a family case].

PubMed

Orío Hernández, M; de la Serna Martínez, M; González Casado, I; Lapunzina, P; Gracia Bouthelier, R

2008-06-01

Neonatal diabetes mellitus (NDM) is characterized by hyperglycemia within the first month of life and insulin dependence for at least two weeks. There are two types of NDM, transient (TNDM) and permanent (PNDM), which are genetically different. We report the case of two brothers who developed hyperglycemia without ketosis on the 18th day and 2 h of life, respectively. Thyroid function tests, abdominal ultrasound and karyotype where normal and there were no pancreatic antibodies. The first one required insulin therapy for the first 92 days of life and the second for 5 months. The mother developed gestational diabetes during both pregnancies and she was later diagnosed diabetes mellitus (without antibodies). They were studied for mutations in KCNJ11 gene (principally related to the permanent form). The three of them showed the E229K mutation (frequently associated with the transient form). A genetic study is essential in NDM to achieve the most accurate prognosis possible.

Thermal finite-element analysis of space shuttle main engine turbine blade

NASA Technical Reports Server (NTRS)

Abdul-Aziz, Ali; Tong, Michael T.; Kaufman, Albert

1987-01-01

Finite-element, transient heat transfer analyses were performed for the first-stage blades of the space shuttle main engine (SSME) high-pressure fuel turbopump. The analyses were based on test engine data provided by Rocketdyne. Heat transfer coefficients were predicted by performing a boundary-layer analysis at steady-state conditions with the STAN5 boundary-layer code. Two different peak-temperature overshoots were evaluated for the startup transient. Cutoff transient conditions were also analyzed. A reduced gas temperature profile based on actual thermocouple data was also considered. Transient heat transfer analyses were conducted with the MARC finite-element computer code.

Effects of Continuous Positive Airway Pressure on Neurocognitive Function in Obstructive Sleep Apnea Patients: The Apnea Positive Pressure Long-term Efficacy Study (APPLES)

PubMed Central

Kushida, Clete A.; Nichols, Deborah A.; Holmes, Tyson H.; Quan, Stuart F.; Walsh, James K.; Gottlieb, Daniel J.; Simon, Richard D.; Guilleminault, Christian; White, David P.; Goodwin, James L.; Schweitzer, Paula K.; Leary, Eileen B.; Hyde, Pamela R.; Hirshkowitz, Max; Green, Sylvan; McEvoy, Linda K.; Chan, Cynthia; Gevins, Alan; Kay, Gary G.; Bloch, Daniel A.; Crabtree, Tami; Dement, William C.

2012-01-01

Study Objective: To determine the neurocognitive effects of continuous positive airway pressure (CPAP) therapy on patients with obstructive sleep apnea (OSA). Design, Setting, and Participants: The Apnea Positive Pressure Long-term Efficacy Study (APPLES) was a 6-month, randomized, double-blind, 2-arm, sham-controlled, multicenter trial conducted at 5 U.S. university, hospital, or private practices. Of 1,516 participants enrolled, 1,105 were randomized, and 1,098 participants diagnosed with OSA contributed to the analysis of the primary outcome measures. Intervention: Active or sham CPAP Measurements: Three neurocognitive variables, each representing a neurocognitive domain: Pathfinder Number Test-Total Time (attention and psychomotor function [A/P]), Buschke Selective Reminding Test-Sum Recall (learning and memory [L/M]), and Sustained Working Memory Test-Overall Mid-Day Score (executive and frontal-lobe function [E/F]) Results: The primary neurocognitive analyses showed a difference between groups for only the E/F variable at the 2 month CPAP visit, but no difference at the 6 month CPAP visit or for the A/P or L/M variables at either the 2 or 6 month visits. When stratified by measures of OSA severity (AHI or oxygen saturation parameters), the primary E/F variable and one secondary E/F neurocognitive variable revealed transient differences between study arms for those with the most severe OSA. Participants in the active CPAP group had a significantly greater ability to remain awake whether measured subjectively by the Epworth Sleepiness Scale or objectively by the maintenance of wakefulness test. Conclusions: CPAP treatment improved both subjectively and objectively measured sleepiness, especially in individuals with severe OSA (AHI > 30). CPAP use resulted in mild, transient improvement in the most sensitive measures of executive and frontal-lobe function for those with severe disease, which suggests the existence of a complex OSA-neurocognitive relationship. Clinical Trial Information: Registered at clinicaltrials.gov. Identifier: NCT00051363. Citation: Kushida CA; Nichols DA; Holmes TH; Quan SF; Walsh JK; Gottlieb DJ; Simon RD; Guilleminault C; White DP; Goodwin JL; Schweitzer PK; Leary EB; Hyde PR; Hirshkowitz M; Green S; McEvoy LK; Chan C; Gevins A; Kay GG; Bloch DA; Crabtree T; Demen WC. Effects of continuous positive airway pressure on neurocognitive function in obstructive sleep apnea patients: the Apnea Positive Pressure Long-term Efficacy Study (APPLES). SLEEP 2012;35(12):1593-1602. PMID:23204602

Dual Functions of Perirhinal Cortex in Fear Conditioning

PubMed Central

Kent, Brianne A.; Brown, Thomas H.

2012-01-01

The present review examines the role of perirhinal cortex (PRC) in Pavlovian fear conditioning. The focus is on rats, partly because so much is known, behaviorally and neurobiologically, about fear conditioning in these animals. In addition, the neuroanatomy and neurophysiology of rat PRC have been described in considerable detail at the cellular and systems levels. The evidence suggests that PRC can serve at least two types of mnemonic functions in Pavlovian fear conditioning. The first function, termed "stimulus unitization," refers to the ability to treat two or more separate items or stimulus elements as a single entity. Supporting evidence for this perceptual function comes from studies of context conditioning as well as delay conditioning to discontinuous auditory cues. In a delay paradigm, the conditional stimulus (CS) and unconditional stimulus (US) overlap temporally and co-terminate. The second PRC function entails a type of "transient memory." Supporting evidence comes from studies of trace cue conditioning, where there is a temporal gap or trace interval between the CS offset and the US onset. For learning to occur, there must be a transient CS representation during the trace interval. We advance a novel neurophysiological mechanism for this transient representation. These two hypothesized functions of PRC are consistent with inferences based on non-aversive forms of learning. PMID:22903623

Single Event Transients in Low Voltage Dropout (LVDO) Voltage Regulators

NASA Technical Reports Server (NTRS)

LaBel, K.; Karsh, J.; Pursley, S.; Kleyner, I.; Katz, R.; Poivey, C.; Kim, H.; Seidleck, C.

2006-01-01

This viewgraph presentation reviews the use of Low Voltage Dropout (LVDO) Voltage Regulators in environments where heavy ion induced Single Event Transients are a concern to the designers.Included in the presentation are results of tests of voltage regulators.

Potential energy barriers to ion transport within lipid bilayers. Studies with tetraphenylborate.

PubMed Central

Andersen, P S; Fuchs, M

1975-01-01

Tetraphenylborate-induced current transients were studied in lipid bilayers formed from bacterial phosphatidylethanolamine in decane. This ion movement was essentially confined to the membrane in terior during the current transients. Charge movement through the interior of the membrane during the current transients was studied as a function of the applied potential. The transferred charge approached an upper limit with increasing potential, which is interpreted to be the amount of charge due to tetraphenylborate ions absorbed into the boundary regions of the bilayer. A further analysis of the charge transfer as a function of potential indicates that the movement of tetraphenylborate ions is only influenced by a certain farction of the applied potential. For bacterial phosphatidylethanolamine bilayers the effective potential is 77 +/- 4% of the applied potential. The initial conductance and the time constant of the current transients were studied as a function of the applied potential using a Nernst-Planck electrodiffusion regime. It was found that an image-force potential energy barrier gave a good prediction of the observed behavior, provided that the effective potential was used in the calculations. We could not get a satisfactory prediction of the observed behavior with an Eyring rate theory model or a trapezoidal potential energy barrier. PMID:1148364

Transient Characterization of Type B Particles in a Transport Riser

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

Shadle, L.J.; Monazam, E.R.; Mei, J.S.

2007-01-01

Simple and rapid dynamic tests were used to evaluate fluid dynamic behavior of granular materials in the transport regime. Particles with densities ranging from 189 to 2,500 kg/m3 and Sauter mean size from 61 to 812 μm were tested in a 0.305 m diameter, 15.5 m height circulating fluidized bed (CFB) riser. The transient tests involved the abrupt stoppage of solids flow for each granular material over a wide range gas flow rates. The riser emptying time was linearly related to the Froude number in each of three different operating regimes. The flow structure along the height of the risermore » followed a distinct pattern as tracked through incremental pressures. These results are discussed to better understand the transformations that take place when operating over various regimes. During the transients the particle size distribution was measured. The effects of pressure, particle size, and density on test performance are also presented.« less

Tantalum capacitor behavior under fast transient overvoltages. [circuit protection against lightning

NASA Technical Reports Server (NTRS)

Zill, J. A.; Castle, K. D.

1974-01-01

Tantalum capacitors were tested to determine failure time when subjected to short-duration, high-voltage surges caused by lightning strikes. Lightning is of concern to NASA because of possible damage to critical spacecraft circuits. The test was designed to determine the minimum time for tantalum capacitor failure and the amount of overvoltage a capacitor could survive, without permanent damage, in 100 microseconds. All tested exhibited good recovery from the transient one-shot pulses with no failure at any voltage, forward or reverse, in less than 25 microseconds.

Results of the ETV-1 breadboard tests under steady-state and transient conditions. [conducted in the NASA-LeRC Road Load Simulator

NASA Technical Reports Server (NTRS)

Sargent, N. B.; Dustin, M. O.

1981-01-01

Steady state tests were run to characterize the system and component efficiencies over the complete speed-torque capabilities of the propulsion system in both motoring and regenerative modes of operation. The steady state data were obtained using a battery simulator to separate the effects on efficiency caused by changing battery state-of-charge and component temperature. Transient tests were performed to determine the energy profiles of the propulsion system operating over the SAE J227a driving schedules.

Analysis and testing of a space crane articulating joint testbed

NASA Technical Reports Server (NTRS)

Sutter, Thomas R.; Wu, K. Chauncey

1992-01-01

The topics are presented in viewgraph form and include: space crane concept with mobile base; mechanical versus structural articulating joint; articulating joint test bed and reference truss; static and dynamic characterization completed for space crane reference truss configuration; improved linear actuators reduce articulating joint test bed backlash; 1-DOF space crane slew maneuver; boom 2 tip transient response finite element dynamic model; boom 2 tip transient response shear-corrected component modes torque driver profile; peak root member force vs. slew time torque driver profile; and open loop control of space crane motion.

The first PANDA tests

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

Dreier, J.; Huggenberger, M.; Aubert, C.

1996-08-01

The PANDA test facility at PSI in Switzerland is used to study the long-term Simplified Boiling Water Reactor (SBWR) Passive Containment Cooling System (PCCS) performance. The PANDA tests demonstrate performance on a larger scale than previous tests and examine the effects of any non-uniform spatial distributions of steam and non-condensables in the system. The PANDA facility has a 1:1 vertical scale, and 1:25 ``system`` scale (volume, power, etc.). Steady-state PCCS condenser performance tests and extensive facility characterization tests have been completed. Transient system behavior tests were conducted late in 1995; results from the first three transient tests (M3 series) aremore » reviewed. The first PANDA tests showed that the overall global behavior of the SBWR containment was globally repeatable and very favorable; the system exhibited great ``robustness.``« less

The sensorimotor and cognitive deficits in rats following 90- and 120-min transient occlusion of the middle cerebral artery.

PubMed

Zvejniece, Liga; Svalbe, Baiba; Liepinsh, Edgars; Pulks, Eduards; Dambrova, Maija

2012-07-15

Middle cerebral artery occlusion (MCAO) is the most commonly used method to study the neurological and histological outcomes and the pathological mechanisms of ischaemic stroke. The current work compares sensorimotor and cognitive deficits and the infarct volume in rats following a transient 90- or 120-min MCAO, which allows the appropriate behavioural tests to be chosen based on the goal and design of the experiment. In the beam-walking test, we found significant differences between the 90- and 120-min MCAO groups in the number of foot faults made with the impaired hindlimb on post-stroke days 3, 7 and 14. In the cylinder test, a difference between the 90- and 120-min groups was observed on post-operation day 14. The responses to tactile and proprioceptive stimulation were impaired to a similar extent after 90- and 120-min MCAO in the vibrissae-evoked forelimb-placing and limb-placing tests. Moreover, we found significant memory impairment in the 120-min MCAO group 6 days after the acquisition trial. The brain tissue damage was significantly higher after 120-min occlusion of the MCA compared with 90-min occlusion; the infarct volumes were 13% and 25% of the contralateral hemispheres, respectively. In conclusion, both the 90- and 120-min occlusion models result in a significant impairment of sensorimotor, tactile and proprioceptive function, but memory impairment is only observed in the 120-min MCAO group. The beam-walking and cylinder tests detected neurological dysfunction after the 120-min MCAO, whereas the limb-placing and vibrissae-evoked forelimb-placing tests were able to evaluate the neurological dysfunction in rats after 90- and 120-min MCAO. Copyright © 2012 Elsevier B.V. All rights reserved.

Structured Evaluation of Glioma Patients by an Occupational Therapist-Is Our Clinical Examination Enough?

PubMed

Freyschlag, Christian Franz; Kerschbaumer, Johannes; Pinggera, Daniel; Bacher, Gabriele; Mur, Erich; Thomé, Claudius

2017-07-01

Preservation of neurologic function is mandatory when offering a surgical intervention to patients with low-grade gliomas (LGGs), given that the goal of any treatment is the patient's return to their normal everyday life. To determine whether a structured evaluation by an occupational therapist can reveal deficits that might be overseen in routine clinical examination of patients with a surgically treated LGG. A total of 20 patients with radiographically suspected LGG were examined in a standardized fashion at 3 stages: preoperatively, postoperatively, and 3 months thereafter. Results were analyzed descriptively. A total of 19 patients (95%) showed no postoperative motor deficit; one suffered from akinesia due to supplementary motor area involvement and demonstrated a transient deficit with manifestation on the first postoperative day. Patients with eloquent LGGs, involving speech (n = 6, 30%), exhibited different transient speech disturbances according to the location of the lesion. Structured testing revealed a postoperative worsening of movement mirroring (upper extremity) and finger discrimination (sensory) in 5 of 20 patients (25%). Force meter evaluation of the upper extremity was decreased significantly postoperatively for the affected hemisphere, even though motor deficits were absent in most patients. The action research arm test detected deterioration in more than one half of the patients postoperatively. Patients recovered from these deficits within the first 3 months. Routine clinical examination and neuropsychological evaluation fail to detect mild deficits in sensory function, reactivity, and apraxia, which may have a serious impact on patients' ability to return to their normal lives and work. Copyright © 2017 Elsevier Inc. All rights reserved.

Immune modulation following immunization with polyvalent vaccines in dogs.

PubMed

Strasser, Alois; May, Bettina; Teltscher, Andrea; Wistrela, Eva; Niedermüller, Hans

2003-08-15

A decline in T-cell-mediated immunity and transient state of immunosuppression after immunization has been reported in dogs. Nevertheless, dogs are still routinely vaccinated with polyvalent live vaccines and severe disease does not generally occur. In order to investigate these effects on the canine immune system and to elucidate possible mechanisms we determined the following immune parameters in the blood of 33 clinically sound German shepherd dogs before and after standard vaccination with a polyvalent vaccine against distemper, parvovirus, viral hepatitis, leptospirosis, kennel cough and rabies: white and differential blood cell count, the serum concentrations and/or activities of IL-1, IL-2, IFN-gamma, TNF-alpha, neopterin and IgG, natural killer (NK) cell activity, bactericidal activity and complement hemolytic activity, lymphocyte proliferation test (LPT) and nitroblue tetrazolium test (NBT). Our major findings were that significant postvaccinal decreases in T-cell mitogenic response to PHA and in neutrophil function and neopterin serum concentration were accompanied by simultaneous increase in plasma IgG and hemolytic complement activity. This suggests a transient shift in the balance between cell-mediated and humoral (T(H)1/T(H)2) immunity rather than immunosuppression. These results do not imply that dogs should not receive live vaccines, as the response to vaccines just seems to create a state of altered homeostasis when immunization elicits protection by humoral and cell-mediated immunity. However, these recognized compromises of immune function should be considered and vaccines still be applied only in healthy animals and strictly according to the rules and regulations given by the manufacturer.

Global dynamic modeling of a transmission system

NASA Technical Reports Server (NTRS)

Choy, F. K.; Qian, W.

1993-01-01

The work performed on global dynamic simulation and noise correlation of gear transmission systems at the University of Akron is outlined. The objective is to develop a comprehensive procedure to simulate the dynamics of the gear transmission system coupled with the effects of gear box vibrations. The developed numerical model is benchmarked with results from experimental tests at NASA Lewis Research Center. The modal synthesis approach is used to develop the global transient vibration analysis procedure used in the model. Modal dynamic characteristics of the rotor-gear-bearing system are calculated by the matrix transfer method while those of the gear box are evaluated by the finite element method (NASTRAN). A three-dimensional, axial-lateral coupled bearing model is used to couple the rotor vibrations with the gear box motion. The vibrations between the individual rotor systems are coupled through the nonlinear gear mesh interactions. The global equations of motion are solved in modal coordinates and the transient vibration of the system is evaluated by a variable time-stepping integration scheme. The relationship between housing vibration and resulting noise of the gear transmission system is generated by linear transfer functions using experimental data. A nonlinear relationship of the noise components to the fundamental mesh frequency is developed using the hypercoherence function. The numerically simulated vibrations and predicted noise of the gear transmission system are compared with the experimental results from the gear noise test rig at NASA Lewis Research Center. Results of the comparison indicate that the global dynamic model developed can accurately simulate the dynamics of a gear transmission system.

Transient liquid-crystal technique used to produce high-resolution convective heat-transfer-coefficient maps

NASA Technical Reports Server (NTRS)

Hippensteele, Steven A.; Poinsatte, Philip E.

1993-01-01

In this transient technique the preheated isothermal model wall simulates the classic one-dimensional, semi-infinite wall heat transfer conduction problem. By knowing the temperature of the air flowing through the model, the initial temperature of the model wall, and the surface cooling rate measured at any location with time (using the fast-response liquid-crystal patterns recorded on video tape), the heat transfer coefficient can be calculated for the color isothermal pattern produced. Although the test was run transiently, the heat transfer coefficients are for the steady-state case. The upstream thermal boundary condition was considered to be isothermal. This transient liquid-crystal heat-transfer technique was used in a transient air tunnel in which a square-inlet, 3-to-1 exit transition duct was placed. The duct was preheated prior to allowing room temperature air to be suddenly drawn through it. The resulting isothermal contours on the duct surfaces were revealed using a surface coating of thermochromic liquid crystals that display distinctive colors at particular temperatures. A video record was made of the temperature and time data for all points on the duct surfaces during each test. The duct surfaces were uniformly heated using two heating systems: the first was an automatic temperature-controlled heater blanket completely surrounding the test duct like an oven, and the second was an internal hot-air loop through the inside of the test duct. The hot-air loop path was confined inside the test duct by insulated heat dams located at the inlet and exit ends of the test duct. A recirculating fan moved hot air into the duct inlet, through the duct, out of the duct exit, through the oven, and back to the duct inlet. The temperature nonuniformity of the test duct model wall was held very small. Test results are reported for two inlet Reynolds numbers of 200,000 and 1,150,000 (based on the square-inlet hydraulic diameter) and two free-stream turbulence intensities of about 1 percent, which is typical of wind tunnels, and up to 20 percent (using a grid), which is typical of real engine conditions.

Mary, a Pipeline to Aid Discovery of Optical Transients

NASA Astrophysics Data System (ADS)

Andreoni, I.; Jacobs, C.; Hegarty, S.; Pritchard, T.; Cooke, J.; Ryder, S.

2017-09-01

The ability to quickly detect transient sources in optical images and trigger multi-wavelength follow up is key for the discovery of fast transients. These include events rare and difficult to detect such as kilonovae, supernova shock breakout, and `orphan' Gamma-ray Burst afterglows. We present the Mary pipeline, a (mostly) automated tool to discover transients during high-cadenced observations with the Dark Energy Camera at Cerro Tololo Inter-American Observatory (CTIO). The observations are part of the `Deeper Wider Faster' programme, a multi-facility, multi-wavelength programme designed to discover fast transients, including counterparts to Fast Radio Bursts and gravitational waves. Our tests of the Mary pipeline on Dark Energy Camera images return a false positive rate of 2.2% and a missed fraction of 3.4% obtained in less than 2 min, which proves the pipeline to be suitable for rapid and high-quality transient searches. The pipeline can be adapted to search for transients in data obtained with imagers other than Dark Energy Camera.

Pulmonary function deficits in newborn screened infants with cystic fibrosis managed with standard UK care are mild and transient.

PubMed

Davies, Gwyneth; Stocks, Janet; Thia, Lena P; Hoo, Ah-Fong; Bush, Andrew; Aurora, Paul; Brennan, Lucy; Lee, Simon; Lum, Sooky; Cottam, Philippa; Miles, Joanne; Chudleigh, Jane; Kirkby, Jane; Balfour-Lynn, Ian M; Carr, Siobhán B; Wallis, Colin; Wyatt, Hilary; Wade, Angie

2017-11-01

With the advent of novel designer molecules for cystic fibrosis (CF) treatment, there is huge need for early-life clinical trial outcomes, such as infant lung function (ILF). We investigated the degree and tracking of ILF abnormality during the first 2 years of life in CF newborn screened infants.Forced expiratory volume in 0.5 s (FEV 0.5 ), lung clearance index (LCI) and plethysmographic functional residual capacity were measured at ∼3 months, 1 year and 2 years in 62 infants with CF and 34 controls.By 2 years there was no significant difference in FEV 0.5 z-score between CF and controls, whereas mean LCI z-score was 0.81 (95% CI 0.45-1.17) higher in CF. However, there was no significant association between LCI z-score at 2 years with either 3-month or 1-year results. Despite minimal average group changes in any ILF outcome during the second year of life, marked within-subject changes occurred. No child had abnormal LCI or FEV 0.5 on all test occasions, precluding the ability to identify "high-risk" infants in early life.In conclusion, changes in lung function are mild and transient during the first 2 years of life in newborn screened infants with CF when managed according to a standardised UK treatment protocol. Their potential role in tracking disease to later childhood will be ascertained by ongoing follow-up. Copyright ©ERS 2017.

Comparison of thin-film resistance heat-transfer gages with thin-skin transient calorimeter gages in conventional hypersonic wind tunnels

NASA Technical Reports Server (NTRS)

Miller, C. G., III

1981-01-01

Thin film gages deposited at the stagnation region of small (8.1-mm-diameter) hemispheres and gages mounted flush with the surface of a sharp-leading-edge flat plate were tested in the Langley continuous-flow hypersonic tunnel and in the Langley hypersonic CF4 tunnel. Two substrate materials were tested, quartz and a machinable glass-ceramic. Small hemispheres were also tested utilizing the thin-skin transient calorimeter technique usually employed in conventional tunnels. One transient calorimeter model was a thin shell of stainless steel, and the other was a thin-skin insert of stainless steel mounted into a hemisphere fabricated from a machinable-glass-ceramic. Measured heat-transfer rates from the various hemispheres were compared with one another and with predicted rates. The results demonstrate the feasibility and advantages of using-film resistance heat-transfer gages in conventional hypersonic wind tunnels over a wide range of conditions.

Steady and transient regimes in hydropower plants

NASA Astrophysics Data System (ADS)

Gajic, A.

2013-12-01

Hydropower plant that has been in operation for about 30 years has to be reconstructed. They have already installed 12 Kaplan turbines, the largest in the world at that time. The existing CAM relationship was determined based on hydraulic model tests and checked by efficiency on-site tests. It was also tested based on turbine bearing vibrations. In order to discover vibrations and long cracks on stay vanes detailed on-site measurements were performed. Influence of the modification of the trailing edges on the dynamic stresses of the stay vanes is also shown. In order to improve power output transient regimes were analyzed, both experimentally and numerically. Reversible hydropower plant, a pioneer in Europe since it was the first Pump storage power plant constructed with the highest head pump-turbines in the world. Analyses of transient regimes discover some problems with S-shaped characteristics coupled with non-symmetrical penstock.

Transient Three-Dimensional Startup Side Load Analysis of a Regeneratively Cooled Nozzle

NASA Technical Reports Server (NTRS)

Wang, Ten-See

2008-01-01

The objective of this effort is to develop a computational methodology to capture the startup side load physics and to anchor the computed aerodynamic side loads with the available data from a regeneratively cooled, high-aspect-ratio nozzle, hot-fired at sea level. The computational methodology is based on an unstructured-grid, pressure-based, reacting flow computational fluid dynamics and heat transfer formulation, a transient 5 s inlet history based on an engine system simulation, and a wall temperature distribution to reflect the effect of regenerative cooling. To understand the effect of regenerative wall cooling, two transient computations were performed using the boundary conditions of adiabatic and cooled walls, respectively. The results show that three types of shock evolution are responsible for side loads: generation of combustion wave; transitions among free-shock separation, restricted-shock separation, and simultaneous free-shock and restricted shock separations; along with the pulsation of shocks across the lip, although the combustion wave is commonly eliminated with the sparklers during actual test. The test measured two side load events: a secondary and lower side load, followed by a primary and peak side load. Results from both wall boundary conditions captured the free-shock separation to restricted-shock separation transition with computed side loads matching the measured secondary side load. For the primary side load, the cooled wall transient produced restricted-shock pulsation across the nozzle lip with peak side load matching that of the test, while the adiabatic wall transient captured shock transitions and free-shock pulsation across the lip with computed peak side load 50% lower than that of the measurement. The computed dominant pulsation frequency of the cooled wall nozzle agrees with that of a separate test, while that of the adiabatic wall nozzle is more than 50% lower than that of the measurement. The computed teepee-like formation and the tangential motion of the shocks during lip pulsation also qualitatively agree with those of test observations. Moreover, a third transient computation was performed with a proportionately shortened 1 s sequence, and lower side loads were obtained with the higher ramp rate.

Swelling and gas release in oxide fuels during fast temperature transients

NASA Astrophysics Data System (ADS)

Dollins, C. C.; Jursich, M.

1982-05-01

A previously reported intergranular swelling and gas release model for oxide fuels has been modified to predict fission gas behavior during fast temperature transients. Under steady state or slowly varying conditions it has been assumed in the previous model that the pressure caused by the fission gas within the gas bubbles is in equilibrium with the surface tension of the bubbles. During a fast transient, however, net vacancy migration to the bubbles may be insufficient to maintain this equilibrium. In order to ascertain the net vacancy flow, it is necessary to model the point defect behavior in the fuel. Knowing the net flow of vacancies to the bubble and the bubble size, the bubble diffusivity can be determined and the long range migration of the gas out of the fuel can be calculated. The model has also been modified to allow release of all the gas on the grain boundaries during a fast temperature transient. The gas release predicted by the revised model shows good agreement to fast transient gas release data from an EBR-II TREAT H-3 (Transient Reactor Test Facility) test. Agreement has also been obtained between predictions using the model and gas release data obtained by Argonne National Laboratory from out-of-reactor transient heating experiments on irradiated UO 2. It was found necessary to increase the gas bubble diffusivity used in the model by a factor of thirty during the transient to provide agreement between calculations and measurements. Other workers have also found that such an increase is necessary for agreement and attribute the increased diffusivity to yielding at the bubble surface due to the increased pressure.

Interleukin-4 Is Essential for Microglia/Macrophage M2 Polarization and Long-Term Recovery After Cerebral Ischemia.

PubMed

Liu, Xiangrong; Liu, Jia; Zhao, Shangfeng; Zhang, Haiyue; Cai, Wei; Cai, Mengfei; Ji, Xunming; Leak, Rehana K; Gao, Yanqin; Chen, Jun; Hu, Xiaoming

2016-02-01

Interleukin-4 (IL-4) is a unique cytokine that may contribute to brain repair by regulating microglia/macrophage functions. Thus, we examined the effect of IL-4 on long-term recovery and microglia/macrophage polarization in 2 well-established stroke models. Transient middle cerebral artery occlusion or permanent distal middle cerebral artery occlusion was induced in wild-type and IL-4 knockout C57/BL6 mice. In a separate cohort of wild-type animals, IL-4 (60 ng/d for 7 days) or vehicle was infused into the cerebroventricle after transient middle cerebral artery occlusion. Behavioral outcomes were assessed by the Rotarod, corner, foot fault, and Morris water maze tests. Neuronal tissue loss was verified by 2 independent neuron markers. Markers of classically activated (M1) and alternatively activated (M2) microglia were assessed by real-time polymerase chain reaction, immunofluorescence, and flow cytometry. Loss of IL-4 exacerbated sensorimotor deficits and impaired cognitive functions ≤21 days post injury. In contrast to the delayed deterioration of neurological functions, IL-4 deficiency increased neuronal tissue loss only in the acute phase (5 days) after stroke and had no impact on neuronal tissue loss 14 or 21 days post injury. Loss of IL-4 promoted expression of M1 microglia/macrophage markers and impaired expression of M2 markers at 5 and 14 days post injury. Administration of IL-4 into the ischemic brain also enhanced long-term functional recovery. The cytokine IL-4 improves long-term neurological outcomes after stroke, perhaps through M2 phenotype induction in microglia/macrophages. These results are the first to suggest that immunomodulation with IL-4 is a promising approach to promote long-term functional recovery after stroke. © 2016 American Heart Association, Inc.

A woman lost in the cemetery: A case of time-limited amnesia.

PubMed

Comparelli, A; De Carolis, A; Kotzalidis, G D; Masillo, A; Ferracuti, S; Tatarelli, R

2010-02-01

A 43-year-old woman one day experienced a dissociative fugue which she could not recall. She was married, nulliparous, with no history of dissociative disorder or other psychiatric disorders. She had been sexually abused during late childhood-early adolescence. She was examined thoroughly from both psychiatric and medical standpoints to exclude organic causes for her condition. Magnetic Resonance Imaging showed only some non-specific abnormalities. On personality tests, a histrionic structure of personality emerged, with obsessive and narcissistic traits accompanied by rigidity and anxiety, dysphoria and high risk for depression; some impairment was found in executive function tests. Final diagnosis was one of dissociative fugue. In fact, organic traits were not sufficient to establish a diagnosis of Transient Global Amnesia.

Electrically-Assisted Turbocharger Development for Performance and Emissions

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

Bailey, Milton

2000-08-20

Turbocharger transient lag inherently imposes a tradeoff between a robust engine response to transient load shifts and exhaust emissions. By itself, a well matched turbocharger for an engine has limited flexibility in improving this transient response. Electrically-assisted turbocharging has been seen as an attractive option to improve response and lower transient emissions. This paper presents the results of a multi-year joint CRADA between DDC and ORNL. Virtual lab diesel simulation models characterized the performance improvement potential of an electrically assisted turbocharger technology. Operating requirements to reduce transient duration between load shift time by up to 50% were determined. A turbomachinemore » has been conceptualized with an integrated motor-generator, providing transient burst boost plus energy recovery capability. Numerous electric motor designs were considered, and a prototype motor was developed, fabricated, and is undergoing tests. Power controls have been designed and fabricated.« less

Cognitive function and the emotional state of stroke patients on antihypertensive therapy.

PubMed

Starchina, Yu A; Parfenov, V A; Chazova, I E; Sinitsyn, V E; Pustovitova, T S; Kolos, I P; Ustyuzhanin, D V

2007-01-01

Combined antihypertensive therapy based on 2.5-5 mg of cilazapril (an angiotensin-converting enzyme inhibitor) to normalize arterial pressure (ABP) was studied in 22 patients (12 male, 10 female) aged 49-74 years (mean 63 +/- 7 years) with stroke (18 patients) or transient ischemic attacks (three patients). Magnetic resonance tomography (MRT) including perfusion studies, along with neuropsychological studies and assessment of emotional status (Beck depression inventory, Spielberger anxiety scale), were performed before and after treatment. After six months of treatment, patients showed normalization of ABP (systolic pressure decreased from 154.7 +/- 12 to 128 +/- 23 mmHg, diastolic from 90.3 +/- 9.6 to 79.4 +/- 23 mmHg). There were no side effects and no patient experienced stroke. MRT revealed no signs of new foci and there were no significant changes in brain blood flow. By the end of treatment, improvements in cognitive functions were noted on the Mini Mental State Examination, the 10-word memory test, the Boston naming test, or the Wisconsin card-sorting test, though there were no changes in the patients' emotional status.

Multiloop Integral System Test (MIST): MIST Facility Functional Specification

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

Habib, T F; Koksal, C G; Moskal, T E

1991-04-01

The Multiloop Integral System Test (MIST) is part of a multiphase program started in 1983 to address small-break loss-of-coolant accidents (SBLOCAs) specific to Babcock and Wilcox designed plants. MIST is sponsored by the US Nuclear Regulatory Commission, the Babcock Wilcox Owners Group, the Electric Power Research Institute, and Babcock and Wilcox. The unique features of the Babcock and Wilcox design, specifically the hot leg U-bends and steam generators, prevented the use of existing integral system data or existing integral facilities to address the thermal-hydraulic SBLOCA questions. MIST was specifically designed and constructed for this program, and an existing facility --more » the Once Through Integral System (OTIS) -- was also used. Data from MIST and OTIS are used to benchmark the adequacy of system codes, such as RELAP5 and TRAC, for predicting abnormal plant transients. The MIST Functional Specification documents as-built design features, dimensions, instrumentation, and test approach. It also presents the scaling basis for the facility and serves to define the scope of work for the facility design and construction. 13 refs., 112 figs., 38 tabs.« less

The hearing system in newborns from the Upper Silesia. Assessment of TEOAE depending on selected parameters of delivery disorders.

PubMed

Namyslowski, G; Morawski, K; Urbaniec, N; Lisowska, G; Trybalska, G; Bazowska, G; Oslislo, A

2001-01-01

Transient evoked otoacoustic emission (TEOAE) is an accepted test for screening of the cochlea function in newborns. In this study 300 newborns was tested using TEOAE, as well as analysing such parameters as birth weight, Apgar scale, bilirubinaemia. The study indicated the tendency of TEOAE to decrease in newborns with low birth weight and low Apgar scores. Hyperbilirubinaemia seems to have an influence on cochlea function monitored by TEOAE, especially if there were simultaneously low Apgar scores. A similar tendency, although slightly stronger, was observed in the preterm newborn group. TEOAE seems to be a good method of recording the negative influence on the cochlea activity such factors as low birth weight and asphyxia. Hyperbilirubinaemia with asphyxia acts upon the cochlea similarly. All these tendencies were observed more strongly in the preterm newborn group. It is concluded that TEOAE analysis demonstrated its utility as a screening test assessing the hearing state in newborns, additionally the associations of cochlea activity was found with a few parameters of delivery disorders.

Development of an algorithm for automatic detection and rating of squeak and rattle events

NASA Astrophysics Data System (ADS)

Chandrika, Unnikrishnan Kuttan; Kim, Jay H.

2010-10-01

A new algorithm for automatic detection and rating of squeak and rattle (S&R) events was developed. The algorithm utilizes the perceived transient loudness (PTL) that approximates the human perception of a transient noise. At first, instantaneous specific loudness time histories are calculated over 1-24 bark range by applying the analytic wavelet transform and Zwicker loudness transform to the recorded noise. Transient specific loudness time histories are then obtained by removing estimated contributions of the background noise from instantaneous specific loudness time histories. These transient specific loudness time histories are summed to obtain the transient loudness time history. Finally, the PTL time history is obtained by applying Glasberg and Moore temporal integration to the transient loudness time history. Detection of S&R events utilizes the PTL time history obtained by summing only 18-24 barks components to take advantage of high signal-to-noise ratio in the high frequency range. A S&R event is identified when the value of the PTL time history exceeds the detection threshold pre-determined by a jury test. The maximum value of the PTL time history is used for rating of S&R events. Another jury test showed that the method performs much better if the PTL time history obtained by summing all frequency components is used. Therefore, r ating of S&R events utilizes this modified PTL time history. Two additional jury tests were conducted to validate the developed detection and rating methods. The algorithm developed in this work will enable automatic detection and rating of S&R events with good accuracy and minimum possibility of false alarm.

Molecular Cloning and Functional Characterization of Xenopus tropicalis Frog Transient Receptor Potential Vanilloid 1 Reveal Its Functional Evolution for Heat, Acid, and Capsaicin Sensitivities in Terrestrial Vertebrates*

PubMed Central

Ohkita, Masashi; Saito, Shigeru; Imagawa, Toshiaki; Takahashi, Kenji; Tominaga, Makoto; Ohta, Toshio

2012-01-01

The functional difference of thermosensitive transient receptor potential (TRP) channels in the evolutionary context has attracted attention, but thus far little information is available on the TRP vanilloid 1 (TRPV1) function of amphibians, which diverged earliest from terrestrial vertebrate lineages. In this study we cloned Xenopus tropicalis frog TRPV1 (xtTRPV1), and functional characterization was performed using HeLa cells heterologously expressing xtTRPV1 (xtTRPV1-HeLa) and dorsal root ganglion neurons isolated from X. tropicalis (xtDRG neurons) by measuring changes in the intracellular calcium concentration ([Ca2+]i). The channel activity was also observed in xtTRPV1-expressing Xenopus oocytes. Furthermore, we tested capsaicin- and heat-induced nocifensive behaviors of the frog X. tropicalis in vivo. At the amino acid level, xtTRPV1 displays ∼60% sequence identity to other terrestrial vertebrate TRPV1 orthologues. Capsaicin induced [Ca2+]i increases in xtTRPV1-HeLa and xtDRG neurons and evoked nocifensive behavior in X. tropicalis. However, its sensitivity was extremely low compared with mammalian orthologues. Low extracellular pH and heat activated xtTRPV1-HeLa and xtDRG neurons. Heat also evoked nocifensive behavior. In oocytes expressing xtTRPV1, inward currents were elicited by heat and low extracellular pH. Mutagenesis analysis revealed that two amino acids (tyrosine 523 and alanine 561) were responsible for the low sensitivity to capsaicin. Taken together, our results indicate that xtTRPV1 functions as a polymodal receptor similar to its mammalian orthologues. The present study demonstrates that TRPV1 functions as a heat- and acid-sensitive channel in the ancestor of terrestrial vertebrates. Because it is possible to examine vanilloid and heat sensitivities in vitro and in vivo, X. tropicalis could be the ideal experimental lower vertebrate animal for the study of TRPV1 function. PMID:22130664

EHV-1 EICP22 protein sequences that mediate its physical interaction with the immediate-early protein are not sufficient to enhance the trans-activation activity of the IE protein.

PubMed

Derbigny, Wilbert A; Kim, Seong K; Jang, Hyung K; O'Callaghan, Dennis J

2002-03-20

The early 293 amino acid EICP22 protein (EICP22P) of equine herpesvirus 1 localizes within the nucleus and functions as an accessory regulatory protein (J. Virol. 68 (1994) 4329). Transient transfection assays indicated that although the EICP22P by itself only minimally trans-activates EHV-1 promoters, the EICP22P functions synergistically with the immediate-early protein (IEP) to enhance expression of EHV-1 early genes (J. Virol. 71 (1997) 1004). We previously showed that the EICP22 protein enhances the DNA-binding activity of the EHV-1 IEP and that it also physically interacts with the IEP (J. Virol. 74 (2000) 1425). In this communication, we employed transient trans-activation assays utilizing EICP22P deletion mutants to address whether the sequences required for EICP22P-IEP physical interactions are essential for EICP22P's ability to interact synergistically with the IEP. Assays employing various classes of the EHV-1 promoters fused to the chloramphenicol acetyl-transferase (CAT) reporter gene indicated that: (1) neither full length nor any of the EICP22P mutants tested was able to overcome repression of the IE promoter elicited by the IEP, (2) the full-length EICP22P interacted synergistically with the IEP to trans-activate the early and late promoters tested, and (3) all of the EICP22P mutants, including those that were able to physically interact with IEP and itself, failed to function synergistically with the IEP to trans-activate representative EHV-1 early and late promoters. The results suggest that EICP22P sequences required for its interaction with the IE protein are not sufficient to mediate its synergistic effect on the trans-activation function of the IEP. The possible explanations as to why sequences in addition to those that mediate EICP22P-IEP interaction and EICP22P self-interactions are essential for the synergistic function of EICP22P are discussed.

Biomimetic engineered muscle with capacity for vascular integration and functional maturation in vivo

PubMed Central

Juhas, Mark; Engelmayr, George C.; Fontanella, Andrew N.; Palmer, Gregory M.; Bursac, Nenad

2014-01-01

Tissue-engineered skeletal muscle can serve as a physiological model of natural muscle and a potential therapeutic vehicle for rapid repair of severe muscle loss and injury. Here, we describe a platform for engineering and testing highly functional biomimetic muscle tissues with a resident satellite cell niche and capacity for robust myogenesis and self-regeneration in vitro. Using a mouse dorsal window implantation model and transduction with fluorescent intracellular calcium indicator, GCaMP3, we nondestructively monitored, in real time, vascular integration and the functional state of engineered muscle in vivo. During a 2-wk period, implanted engineered muscle exhibited a steady ingrowth of blood-perfused microvasculature along with an increase in amplitude of calcium transients and force of contraction. We also demonstrated superior structural organization, vascularization, and contractile function of fully differentiated vs. undifferentiated engineered muscle implants. The described in vitro and in vivo models of biomimetic engineered muscle represent enabling technology for novel studies of skeletal muscle function and regeneration. PMID:24706792

Silicon Carbide Diodes Characterization at High Temperature and Comparison With Silicon Devices

NASA Technical Reports Server (NTRS)

Lebron-Velilla, Ramon C.; Schwarze, Gene E.; Gardner, Brent G.; Adams, Jerry D., Jr.

2004-01-01

Commercially available silicon carbide (SiC) Schottky diodes from different manufacturers rated at 200, 300, 600, and 1200 V, were electrically tested and characterized as a function of temperature up to 300 C. Electrical tests included both steady state and dynamic tests. Steady state tests produced forward and reverse I-V characteristic curves. Transient tests evaluated the switching performance of the diodes in either a hard-switched DC to DC buck converter or a half-bridge boost converter. For evaluation and comparison purposes, the same tests were performed with current state-of-the-art ultra fast silicon (Si) pn-junction diodes of similar ratings and also a Si Schottky diode. The comparisons made were forward voltage drop at rated current, reverse current at rated voltage, and turn-off peak reverse recovery current and reverse recovery time. In addition, efficiency measurements were taken for the buck DC to DC converter using both the SiC Schottky diodes and the Si pn-junction diodes at different temperatures and frequencies. The test results showed that at high temperature, the forward voltage drop for SiC Schottky diodes is higher than the forward drop of the ultra fast Si pn-junction diodes. As the temperature increased, the forward voltage drop of the SiC Schottky increased while for the ultra fast Si pn-junction diodes, the forward voltage drop decreased as temperature increased. For the elevated temperature steady state reverse voltage tests, the SiC Schottky diodes showed low leakage current at their rated voltage. Likewise, for the transient tests, the SiC Schottky diodes displayed low reverse recovery currents over the range of temperatures tested. Conversely, the Si pn-junction diodes showed increasing peak reverse current values and reverse recovery times with increasing temperature. Efficiency measurements in the DC to DC buck converter showed the advantage of the SiC Schottky diodes over the ultra fast Si pn-junction diodes, especially at the higher temperatures and higher frequencies.

OPTICAL THERMONUCLEAR TRANSIENTS FROM TIDAL COMPRESSION OF WHITE DWARFS AS TRACERS OF THE LOW END OF THE MASSIVE BLACK HOLE MASS FUNCTION

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

MacLeod, Morgan; Ramirez-Ruiz, Enrico; Guillochon, James

In this paper, we model the observable signatures of tidal disruptions of white dwarf (WD) stars using massive black holes (MBHs) of moderate mass, ≈10{sup 3}–10{sup 5} M{sub ⊙}. When the WD passes deep enough within the MBH’s tidal field, these signatures include thermonuclear transients from burning during maximum compression. We combine a hydrodynamic simulation that includes nuclear burning of the disruption of a 0.6 M{sub ⊙} C/O WD with a Monte Carlo radiative transfer calculation to synthesize the properties of a representative transient. The transient’s emission emerges in the optical, with light curves and spectra reminiscent of Type I supernovae. Themore » properties are strongly viewing angle dependent, and key spectral signatures are ≈10,000 km s{sup −1} doppler shifts, due to the orbital motion of the unbound ejecta. Disruptions of He WDs likely produce large quantities of intermediate-mass elements, offering a possible production mechanism for Ca-rich transients. Accompanying multi-wavelength transients are fueled by accretion and arise from the nascent accretion disk and relativistic jet. If MBHs of moderate mass exist with number densities similar to those of supermassive BHs, both high-energy wide-field monitors and upcoming optical surveys should detect tens to hundreds of WD tidal disruptions per year. The current best strategy for their detection may therefore be deep optical follow-up of high-energy transients of unusually long duration. The detection rate or the nondetection of these transients by current and upcoming surveys can thus be used to place meaningful constraints on the extrapolation of the MBH mass function to moderate masses.« less

Investigation of Natural Circulation Instability and Transients in Passively Safe Small Modular Reactors

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

Ishii, Mamoru

The NEUP funded project, NEUP-3496, aims to experimentally investigate two-phase natural circulation flow instability that could occur in Small Modular Reactors (SMRs), especially for natural circulation SMRs. The objective has been achieved by systematically performing tests to study the general natural circulation instability characteristics and the natural circulation behavior under start-up or design basis accident conditions. Experimental data sets highlighting the effect of void reactivity feedback as well as the effect of power ramp-up rate and system pressure have been used to develop a comprehensive stability map. The safety analysis code, RELAP5, has been used to evaluate experimental results andmore » models. Improvements to the constitutive relations for flashing have been made in order to develop a reliable analysis tool. This research has been focusing on two generic SMR designs, i.e. a small modular Simplified Boiling Water Reactor (SBWR) like design and a small integral Pressurized Water Reactor (PWR) like design. A BWR-type natural circulation test facility was firstly built based on the three-level scaling analysis of the Purdue Novel Modular Reactor (NMR) with an electric output of 50 MWe, namely NMR-50, which represents a BWR-type SMR with a significantly reduced reactor pressure vessel (RPV) height. The experimental facility was installed with various equipment to measure thermalhydraulic parameters such as pressure, temperature, mass flow rate and void fraction. Characterization tests were performed before the startup transient tests and quasi-steady tests to determine the loop flow resistance. The control system and data acquisition system were programmed with LabVIEW to realize the realtime control and data storage. The thermal-hydraulic and nuclear coupled startup transients were performed to investigate the flow instabilities at low pressure and low power conditions for NMR-50. Two different power ramps were chosen to study the effect of startup power density on the flow instability. The experimental startup transient results showed the existence of three different flow instability mechanisms, i.e., flashing instability, condensation induced flow instability, and density wave oscillations. In addition, the void-reactivity feedback did not have significant effects on the flow instability during the startup transients for NMR-50. ii Several initial startup procedures with different power ramp rates were experimentally investigated to eliminate the flow instabilities observed from the startup transients. Particularly, the very slow startup transient and pressurized startup transient tests were performed and compared. It was found that the very slow startup transients by applying very small power density can eliminate the flashing oscillations in the single-phase natural circulation and stabilize the flow oscillations in the phase of net vapor generation. The initially pressurized startup procedure was tested to eliminate the flashing instability during the startup transients as well. The pressurized startup procedure included the initial pressurization, heat-up, and venting process. The startup transient tests showed that the pressurized startup procedure could eliminate the flow instability during the transition from single-phase flow to two-phase flow at low pressure conditions. The experimental results indicated that both startup procedures were applicable to the initial startup of NMR. However, the pressurized startup procedures might be preferred due to short operating hours required. In order to have a deeper understanding of natural circulation flow instability, the quasi-steady tests were performed using the test facility installed with preheater and subcooler. The effect of system pressure, core inlet subcooling, core power density, inlet flow resistance coefficient, and void reactivity feedback were investigated in the quasi-steady state tests. The experimental stability boundaries were determined between unstable and stable flow conditions in the dimensionless stability plane of inlet subcooling number and Zuber number. To predict the stability boundary theoretically, linear stability analysis in the frequency domain was performed at four sections of the natural circulation test loop. The flashing phenomena in the chimney section was considered as an axially uniform heat source. And the dimensionless characteristic equation of the pressure drop perturbation was obtained by considering the void fraction effect and outlet flow resistance in the core section. The theoretical flashing boundary showed some discrepancies with previous experimental data from the quasi-steady state tests. In the future, thermal non-equilibrium was recommended to improve the accuracy of flashing instability boundary. As another part of the funded research, flow instabilities of a PWR-type SMR under low pressure and low power conditions were investigated experimentally as well. The NuScale reactor design was selected as the prototype for the PWR-type SMR. In order to experimentally study the natural circulation behavior of NuScale iii reactor during accidental scenarios, detailed scaling analyses are necessary to ensure that the scaled phenomena could be obtained in a laboratory test facility. The three-level scaling method is used as well to obtain the scaling ratios derived from various non-dimensional numbers. The design of the ideally scaled facility (ISF) was initially accomplished based on these scaling ratios. Then the engineering scaled facility (ESF) was designed and constructed based on the ISF by considering engineering limitations including laboratory space, pipe size, and pipe connections etc. PWR-type SMR experiments were performed in this well-scaled test facility to investigate the potential thermal hydraulic flow instability during the blowdown events, which might occur during the loss of coolant accident (LOCA) and loss of heat sink accident (LOHS) of the prototype PWR-type SMR. Two kinds of experiments, normal blowdown event and cold blowdown event, were experimentally investigated and compared with code predictions. The normal blowdown event was experimentally simulated since an initial condition where the pressure was lower than the designed pressure of the experiment facility, while the code prediction of blowdown started from the normal operation condition. Important thermal hydraulic parameters including reactor pressure vessel (RPV) pressure, containment pressure, local void fraction and temperature, pressure drop and natural circulation flow rate were measured and analyzed during the blowdown event. The pressure and water level transients are similar to the experimental results published by NuScale [51], which proves the capability of current loop in simulating the thermal hydraulic transient of real PWR-type SMR. During the 20000s blowdown experiment, water level in the core was always above the active fuel assemble during the experiment and proved the safety of natural circulation cooling and water recycling design of PWR-type SMR. Besides, pressure, temperature, and water level transient can be accurately predicted by RELAP5 code. However, the oscillations of natural circulation flow rate, water level and pressure drops were observed during the blowdown transients. This kind of flow oscillations are related to the water level and the location upper plenum, which is a path for coolant flow from chimney to steam generator and down comer. In order to investigate the transients start from the opening of ADS valve in both experimental and numerical way, the cold blow-down experiment is conducted. For the cold blowdown event, different from setting both reactor iv pressure vessel (RPV) and containment at high temperature and pressure, only RPV was heated close to the highest designed pressure and then open the ADS valve, same process was predicted using RELAP5 code. By doing cold blowdown experiment, the entire transients from the opening of ADS can be investigated by code and benchmarked with experimental data. Similar flow instability observed in the cold blowdown experiment. The comparison between code prediction and experiment data showed that the RELAP5 code can successfully predict the pressure void fraction and temperature transient during the cold blowdown event with limited error, but numerical instability exists in predicting natural circulation flow rate. Besides, the code is lack of capability in predicting the water level related flow instability observed in experiments.« less

Synchronizing noisy nonidentical oscillators by transient uncoupling

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

Tandon, Aditya, E-mail: adityat@iitk.ac.in; Mannattil, Manu, E-mail: mmanu@iitk.ac.in; Schröder, Malte, E-mail: malte@nld.ds.mpg.de

2016-09-15

Synchronization is the process of achieving identical dynamics among coupled identical units. If the units are different from each other, their dynamics cannot become identical; yet, after transients, there may emerge a functional relationship between them—a phenomenon termed “generalized synchronization.” Here, we show that the concept of transient uncoupling, recently introduced for synchronizing identical units, also supports generalized synchronization among nonidentical chaotic units. Generalized synchronization can be achieved by transient uncoupling even when it is impossible by regular coupling. We furthermore demonstrate that transient uncoupling stabilizes synchronization in the presence of common noise. Transient uncoupling works best if the unitsmore » stay uncoupled whenever the driven orbit visits regions that are locally diverging in its phase space. Thus, to select a favorable uncoupling region, we propose an intuitive method that measures the local divergence at the phase points of the driven unit's trajectory by linearizing the flow and subsequently suppresses the divergence by uncoupling.« less

The Impact of Threat of Shock-Induced Anxiety on Memory Encoding and Retrieval

ERIC Educational Resources Information Center

Bolton, Sorcha; Robinson, Oliver J.

2017-01-01

Anxiety disorders are the most common mental health disorders, and daily transient feelings of anxiety (or "stress") are ubiquitous. However, the precise impact of both transient and pathological anxiety on higher-order cognitive functions, including short- and long-term memory, is poorly understood. A clearer understanding of the…

The intensity recovery of Forbush-type decreases as a function of heliocentric distance and its relationship to the 11-year variation

NASA Astrophysics Data System (ADS)

Lockwood, J. A.; Webber, W. R.; Jokipii, J. R.

1985-08-01

Recent data indicating that the solar modulation effects are propagated outward in the heliospheric cavity suggest that the 11-year cosmic ray modulation can best be described by a dynamic time dependent model. In this context an understanding of the recovery characteristics of large transient Forbush type decreases is important. This includes the typical recovery time at a fixed energy at 1 AU as well as at large heliocentric radial distances, the energy dependence of the recovery time at 1 Au, and the dependence of the time for the intensity to decrease to the minimum in the transient decreases as a function of distance. These transient decreases are characterized by their asymmetrical decrease and recovery times, generally 1 to 2 days and 3 to 10 days respectively at approx. 1 AU. Near earth these are referred to as Forbush decreases, associated witha shock or blast wave passage. At R equal to or greater than + or - 10 AU, these transient decreases may represent the combined effects of several shock waves that have merged together.

Transient Thermoelectric Solution Employing Green's Functions

NASA Technical Reports Server (NTRS)

Mackey, Jon; Sehirlioglu, Alp; Dynys, Fred

2014-01-01

The study works to formulate convenient solutions to the problem of a thermoelectric couple operating under a time varying condition. Transient operation of a thermoelectric will become increasingly common as thermoelectric technology permits applications in an increasing number of uses. A number of terrestrial applications, in contrast to steady-state space applications, can subject devices to time varying conditions. For instance thermoelectrics can be exposed to transient conditions in the automotive industry depending on engine system dynamics along with factors like driving style. In an effort to generalize the thermoelectric solution a Greens function method is used, so that arbitrary time varying boundary and initial conditions may be applied to the system without reformulation. The solution demonstrates that in thermoelectric applications of a transient nature additional factors must be taken into account and optimized. For instance, the materials specific heat and density become critical parameters in addition to the thermal mass of a heat sink or the details of the thermal profile, such as oscillating frequency. The calculations can yield the optimum operating conditions to maximize power output andor efficiency for a given type of device.

Large liquid rocket engine transient performance simulation system

NASA Technical Reports Server (NTRS)

Mason, J. R.; Southwick, R. D.

1991-01-01

A simulation system, ROCETS, was designed and developed to allow cost-effective computer predictions of liquid rocket engine transient performance. The system allows a user to generate a simulation of any rocket engine configuration using component modules stored in a library through high-level input commands. The system library currently contains 24 component modules, 57 sub-modules and maps, and 33 system routines and utilities. FORTRAN models from other sources can be operated in the system upon inclusion of interface information on comment cards. Operation of the simulation is simplified for the user by run, execution, and output processors. The simulation system makes available steady-state trim balance, transient operation, and linear partial generation. The system utilizes a modern equation solver for efficient operation of the simulations. Transient integration methods include integral and differential forms for the trapezoidal, first order Gear, and second order Gear corrector equations. A detailed technology test bed engine (TTBE) model was generated to be used as the acceptance test of the simulation system. The general level of model detail was that reflected in the Space Shuttle Main Engine DTM. The model successfully obtained steady-state balance in main stage operation and simulated throttle transients, including engine starts and shutdown. A NASA FORTRAN control model was obtained, ROCETS interface installed in comment cards, and operated with the TTBE model in closed-loop transient mode.

Characterization of the startup transient electrokinetic flow in rectangular channels of arbitrary dimensions, zeta potential distribution, and time-varying pressure gradient.

PubMed

Miller, Andrew; Villegas, Arturo; Diez, F Javier

2015-03-01

The solution to the startup transient EOF in an arbitrary rectangular microchannel is derived analytically and validated experimentally. This full 2D transient solution describes the evolution of the flow through five distinct periods until reaching a final steady state. The derived analytical velocity solution is validated experimentally for different channel sizes and aspect ratios under time-varying pressure gradients. The experiments used a time resolved micro particle image velocimetry technique to calculate the startup transient velocity profiles. The measurements captured the effect of time-varying pressure gradient fields derived in the analytical solutions. This is tested by using small reservoirs at both ends of the channel which allowed a time-varying pressure gradient to develop with a time scale on the order of the transient EOF. Results showed that under these common conditions, the effect of the pressure build up in the reservoirs on the temporal development of the transient startup EOF in the channels cannot be neglected. The measurements also captured the analytical predictions for channel walls made of different materials (i.e., zeta potentials). This was tested in channels that had three PDMS and one quartz wall, resulting in a flow with an asymmetric velocity profile due to variations in the zeta potential between the walls. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Summary of efficiency testing of standard and high-capacity high-efficiency particulate air filters subjected to simulated tornado depressurization and explosive shock waves

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

Smith, P.R.; Gregory, W.S.

1985-04-01

Pressure transients in nuclear facility air cleaning systems can originate from natural phenomena such as tornadoes or from accident-induced explosive blast waves. This study was concerned with the effective efficiency of high-efficiency particulate air (HEPA) filters during pressure surges resulting from simulated tornado and explosion transients. The primary objective of the study was to examine filter efficiencies at pressure levels below the point of structural failure. Both standard and high-capacity 0.61-m by 0.61-m HEPA filters were evaluated, as were several 0.2-m by 0.2-m HEPA filters. For a particular manufacturer, the material release when subjected to tornado transients is the samemore » (per unit area) for both the 0.2-m by 0.2-m and the 0.61-m by 0.61-m filters. For tornado transients, the material release was on the order of micrograms per square meter. When subjecting clean HEPA filters to simulated tornado transients with aerosol entrained in the pressure pulse, all filters tested showed a degradation of filter efficiency. For explosive transients, the material release from preloaded high-capacity filters was as much as 340 g. When preloaded high-capacity filters were subjected to shock waves approximately 50% of the structural limit level, 1 to 2 mg of particulate was released.« less

PIV Measurement of Transient 3-D (Liquid and Gas Phases) Flow Structures Created by a Spreading Flame over 1-Propanol

NASA Technical Reports Server (NTRS)

Hassan, M. I.; Kuwana, K.; Saito, K.

2001-01-01

In the past, we measured three-D flow structure in the liquid and gas phases that were created by a spreading flame over liquid fuels. In that effort, we employed several different techniques including our original laser sheet particle tracking (LSPT) technique, which is capable of measuring transient 2-D flow structures. Recently we obtained a state-of-the-art integrated particle image velocimetry (IPIV), whose function is similar to LSPT, but it has an integrated data recording and processing system. To evaluate the accuracy of our IPIV system, we conducted a series of flame spread tests using the same experimental apparatus that we used in our previous flame spread studies and obtained a series of 2-D flow profiles corresponding to our previous LSPT measurements. We confirmed that both LSPT and IPIV techniques produced similar data, but IPIV data contains more detailed flow structures than LSPT data. Here we present some of newly obtained IPIV flow structure data, and discuss the role of gravity in the flame-induced flow structures. Note that the application of IPIV to our flame spread problems is not straightforward, and it required several preliminary tests for its accuracy including this IPIV comparison to LSPT.

Transient Three-Dimensional Side Load Analysis of Out-of-Round Film Cooled Nozzles

NASA Technical Reports Server (NTRS)

Wang, Ten-See; Lin, Jeff; Ruf, Joe; Guidos, Mike

2010-01-01

The objective of this study is to investigate the effect of nozzle out-of-roundness on the transient startup side loads. The out-of-roundness could be the result of asymmetric loads induced by hardware attached to the nozzle, asymmetric internal stresses induced by previous tests and/or deformation, such as creep, from previous tests. The rocket engine studied encompasses a regeneratively cooled thrust chamber and a film cooled nozzle extension with film coolant distributed from a turbine exhaust manifold. The computational methodology is based on an unstructured-grid, pressure-based computational fluid dynamics formulation, and a transient inlet history based on an engine system simulation. Transient startup computations were performed with the out-of-roundness achieved by four degrees of ovalization of the nozzle: one perfectly round, one slightly out-of-round, one more out-of-round, and one significantly out-of-round. The computed side load physics caused by the nozzle out-of-roundness and its effect on nozzle side load are reported and discussed.

Data and results of a laboratory investigation of microprocessor upset caused by simulated lightning-induced analog transients

NASA Technical Reports Server (NTRS)

Belcastro, C. M.

1984-01-01

A methodology was developed a assess the upset susceptibility/reliability of a computer system onboard an aircraft flying through a lightning environment. Upset error modes in a general purpose microprocessor were studied. The upset tests involved the random input of analog transients which model lightning induced signals onto interface lines of an 8080 based microcomputer from which upset error data was recorded. The program code on the microprocessor during tests is designed to exercise all of the machine cycles and memory addressing techniques implemented in the 8080 central processing unit. A statistical analysis is presented in which possible correlations are established between the probability of upset occurrence and transient signal inputs during specific processing states and operations. A stochastic upset susceptibility model for the 8080 microprocessor is presented. The susceptibility of this microprocessor to upset, once analog transients have entered the system, is determined analytically by calculating the state probabilities of the stochastic model.

Aeroelastic Modeling of a Nozzle Startup Transient

NASA Technical Reports Server (NTRS)

Wang, Ten-See; Zhao, Xiang; Zhang, Sijun; Chen, Yen-Sen

2014-01-01

Lateral nozzle forces are known to cause severe structural damage to any new rocket engine in development during test. While three-dimensional, transient, turbulent, chemically reacting computational fluid dynamics methodology has been demonstrated to capture major side load physics with rigid nozzles, hot-fire tests often show nozzle structure deformation during major side load events, leading to structural damages if structural strengthening measures were not taken. The modeling picture is incomplete without the capability to address the two-way responses between the structure and fluid. The objective of this study is to develop a tightly coupled aeroelastic modeling algorithm by implementing the necessary structural dynamics component into an anchored computational fluid dynamics methodology. The computational fluid dynamics component is based on an unstructured-grid, pressure-based computational fluid dynamics formulation, while the computational structural dynamics component is developed under the framework of modal analysis. Transient aeroelastic nozzle startup analyses at sea level were performed, and the computed transient nozzle fluid-structure interaction physics presented,

Hearing and loud music exposure in a group of adolescents at the ages of 14-15 and retested at 17-18.

PubMed

Biassoni, Ester C; Serra, Mario R; Hinalaf, María; Abraham, Mónica; Pavlik, Marta; Villalobo, Jorge Pérez; Curet, Carlos; Joekes, Silvia; Yacci, María R; Righetti, Andrea

2014-01-01

Young people expose themselves to potentially damaging loud sounds while leisure activities and noise induced hearing loss is diagnosed in increasing number of adolescents. Hearing and music exposure in a group of adolescents of a technical high school was assessed at the ages of: 14-15 (test) and 17-18 (retest). The aims of the current study were: (1) To compare the auditory function between test and retest; (2) to compare the musical exposure levels during recreational activities in test and retest; (3) to compare the auditory function with the musical exposure along time in a subgroup of adolescents. The participants in the test were 172 male; in the retest, this number was reduced to 59. At the test and retest the conventional and extended high frequency audiometry, transient evoked otoacoustic emissions (TEOAEs) and recreational habits questionnaire were performed. In the test, hearing threshold levels (HTLs) were classified as: Normal (Group 1), slightly shifted (Group 2), and significantly shifted (Group 3); the Musical General Exposure (MGE), categorized in: Low, moderate, high, and very high exposure. The results revealed a significant difference (P < 0.0001) between test and retest in the HTL and global amplitude of TEOAEs in Group 1, showing an increase of the HTL and a decrease TEOAEs amplitude. A subgroup of adolescents, with normal hearing and low exposure to music in the test, showed an increase of the HTL according with the categories of MGE in the retest. To implement educational programs for assessing hearing function, ear vulnerability and to promote hearing health, would be advisable.

Anodal transcranial direct current stimulation transiently improves contrast sensitivity and normalizes visual cortex activation in individuals with amblyopia.

PubMed

Spiegel, Daniel P; Byblow, Winston D; Hess, Robert F; Thompson, Benjamin

2013-10-01

Amblyopia is a neurodevelopmental disorder of vision that is associated with abnormal patterns of neural inhibition within the visual cortex. This disorder is often considered to be untreatable in adulthood because of insufficient visual cortex plasticity. There is increasing evidence that interventions that target inhibitory interactions within the visual cortex, including certain types of noninvasive brain stimulation, can improve visual function in adults with amblyopia. We tested the hypothesis that anodal transcranial direct current stimulation (a-tDCS) would improve visual function in adults with amblyopia by enhancing the neural response to inputs from the amblyopic eye. Thirteen adults with amblyopia participated and contrast sensitivity in the amblyopic and fellow fixing eye was assessed before, during and after a-tDCS or cathodal tDCS (c-tDCS). Five participants also completed a functional magnetic resonance imaging (fMRI) study designed to investigate the effect of a-tDCS on the blood oxygen level-dependent response within the visual cortex to inputs from the amblyopic versus the fellow fixing eye. A subgroup of 8/13 participants showed a transient improvement in amblyopic eye contrast sensitivity for at least 30 minutes after a-tDCS. fMRI measurements indicated that the characteristic cortical response asymmetry in amblyopes, which favors the fellow eye, was reduced by a-tDCS. These preliminary results suggest that a-tDCS deserves further investigation as a potential tool to enhance amblyopia treatment outcomes in adults.

Fast Flux Test Facility thermal and pressure transient events during Cycle 11

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

Ahrens, D. M.

1992-03-01

This report documents the thermal and pressure transients experienced by the Reactor Heat Transport System (RHTS) during Cycle 11 which included Cycles 11A, 11B-1, 11B-2 and 11C (i.e. 4 startups and 4 shutdowns). Cycle 11 consisted of a refueling period that began on March 14, 1989 and power operation which began on May 3, 1989 and ended on October 27, 1990. Transients resulted from secondary pump starts/stops while at refueling conditions. The major causes of transients at power were five unplanned reactor scrams from 100% power and problems with Loop 2 DHX Fan Controls During 11A.

Heavy Ion Microbeam- and Broadbeam-Induced Current Transients in SiGe HBTs

NASA Technical Reports Server (NTRS)

Pellish, Jonathan A.; Reed, R. A.; McMorrow, D.; Vizkelethy, G.; Ferlet-Cavrois, V.; Baggio, J.; Duhamel, O.; Moen, K. A.; Phillips, S. D.; Diestelhorst, R. M.;

Effects of geoduck (Panopea generosa) aquaculture on resident and transient macrofauna communities of Puget Sound, Washington, USA

USGS Publications Warehouse

Mcdonald, P. Sean; Galloway, Aaron W.E.; McPeek, Kathleen C.; VanBlaricom, Glenn R.

2015-01-01

In Washington state, commercial culture of geoducks (Panopea generosa) involves large-scale out-planting of juveniles to intertidal habitats, and installation of PVC tubes and netting to exclude predators and increase early survival. Structures associated with this nascent aquaculture method are examined to determine whether they affect patterns of use by resident and transient macrofauna. Results are summarized from regular surveys of aquaculture operations and reference beaches in 2009 to 2011 at three sites during three phases of culture: (1) pregear (-geoducks, -structure), (2) gear present (+geoducks, +structures), and (3) postgear (+geoducks, -structures). Resident macroinvertebrates (infauna and epifauna) were sampled monthly (in most cases) using coring methods at low tide during all three phases. Differences in community composition between culture plots and reference areas were examined with permutational analysis of variance and homogeneity of multivariate dispersion tests. Scuba and shoreline transect surveys were used to examine habitat use by transient fish and macroinvertebrates. Analysis of similarity and complementary nonmetric multidimensional scaling were used to compare differences between species functional groups and habitat type during different aquaculture phases. Results suggest that resident and transient macrofauna respond differently to structures associated with geoduck aquaculture. No consistent differences in the community of resident macrofauna were observed at culture plots or reference areas at the three sites during any year. Conversely, total abundance of transient fish and macroinvertebrates were more than two times greater at culture plots than reference areas when aquaculture structures were in place. Community composition differed (analysis of similarity) between culture and reference plots during the gear-present phase, but did not persist to the next farming stage (postgear). Habitat complexity associated with shellfish aquaculture may attract some structure-associated transient species observed infrequently on reference beaches, and may displace other species that typically occur in areas lacking epibenthic structure. This study provides a first look at the effects of multiple phases of geoduck farming on macrofauna, and has important implications for the management of a rapidly expanding sector of the aquaculture industry.

The performance of hafnium and gadolinium self powered neutron detectors in the TREAT reactor

NASA Astrophysics Data System (ADS)

Imel, G. R.; Hart, P. R.

1996-05-01

The use of gadolinium and hafnium self powered neutron detectors in a transient reactor is described in this paper. The detectors were calibrated to the fission rate of U-235 using calibrated fission chambers; the calibration factors were tested in two reactors in steady state and found to be consistent. Calibration of the detectors in transient reactor conditions was done by using uranium wires that were analyzed by radiochemistry techniques to determine total fissions during the transient. This was correlated to the time-integrated current of the detectors during the transient. A temperature correction factor was derived to account for self-shielding effects in the hafnium and gadolinium detectors. The dynamic response of the detectors under transient conditions was studied, and found to be excellent.

Attempting to link hydro-morphology, transient storage and metabolism in streams: Insights from reactive tracer experiments

NASA Astrophysics Data System (ADS)

Kurz, Marie J.; Schmidt, Christian; Blaen, Phillip; Knapp, Julia L. A.; Drummond, Jennifer D.; Martí, Eugenia; Zarnetske, Jay P.; Ward, Adam S.; Krause, Stefan

2016-04-01

In-stream transient storage zones, including the hyporheic zone and vegetation beds, can be hotspots of biogeochemical processing in streams, enhancing ecosystem functions such as metabolism and nutrient uptake. The spatio-temporal dynamics and reactivity of these storage zones are influenced by multiple factors, including channel geomorphology, substrate composition and hydrology, and by anthropogenic modifications to flow regimes and nutrient loads. Tracer injections are a commonly employed method to evaluate solute transport and transient storage in streams; however, reactive tracers are needed to differentiate between metabolically active and inactive transient storage zones. The reactive stream tracer resazurin (Raz), a weakly fluorescent dye which irreversibly transforms to resorufin (Rru) under mildly reducing conditions, provides a proxy for aerobic respiration and an estimate of the metabolic activity associated with transient storage zones. Across a range of lotic ecosystems, we try to assess the influence of stream channel hydro-morphology, morphologic heterogeneity, and substrate type on reach (103 m) and sub-reach (102 m) scale transient storage, respiration, and nutrient uptake. To do so, we coupled injections of Raz and conservative tracers (uranine and/or salt) at each study site. The study sites included: vegetated mesocosms controlled for water depth; vegetated and un-vegetated sediment-filled mesocosms fed by waste-water effluent; a contrasting sand- vs. gravel-bedded lowland stream (Q = 0.08 m3/s); and a series of upland streams with varying size (Q = 0.1 - 1.5 m3/s) and prevalence of morphologic features. Continuous time-series of tracer concentrations were recorded using in-situ fluorometers and EC loggers. At the stream sites, time-series were recorded at multiple downstream locations in order to resolve sub-reach dynamics. Analyses yielded highly variable transport metrics and Raz-Rru transformation between study sites and between sub-reaches within stream sites. Higher Raz-Rru transformation rates were typically observed in smaller streams, in sub-reaches with higher prevalence of morphologic features known to promote hyporheic exchange, and in mesocosms with higher water depth, vegetation density and retention time. However, relationships between transformation rates and common metrics of transient storage were not consistent among study cases, indicating the existence of yet unrealized complexities in the relationships between water and solute transport and metabolism. Further insights were also gained related to the utility of Raz and improved tracer test practices.

Picosecond Transient Photoconductivity in Functionalized Pentacene Molecular Crystals Probed by Terahertz Pulse Spectroscopy

NASA Astrophysics Data System (ADS)

Hegmann, F. A.; Tykwinski, R. R.; Lui, K. P.; Bullock, J. E.; Anthony, J. E.

2002-11-01

We have measured transient photoconductivity in functionalized pentacene molecular crystals using ultrafast optical pump-terahertz probe techniques. The single crystal samples were excited using 800nm, 100fs pulses, and the change in transmission of time-delayed, subpicosecond terahertz pulses was used to probe the photoconducting state over a temperature range from 10 to 300K. A subpicosecond rise in photoconductivity is observed, suggesting that mobile carriers are a primary photoexcitation. At times longer than 4ps, a power-law decay is observed consistent with dispersive transport.

A simplified model for tritium permeation transient predictions when trapping is active*1

NASA Astrophysics Data System (ADS)

Longhurst, G. R.

1994-09-01

This report describes a simplified one-dimensional tritium permeation and retention model. The model makes use of the same physical mechanisms as more sophisticated, time-transient codes such as implantation, recombination, diffusion, trapping and thermal gradient effects. It takes advantage of a number of simplifications and approximations to solve the steady-state problem and then provides interpolating functions to make estimates of intermediate states based on the steady-state solution. Comparison calculations with the verified and validated TMAP4 transient code show good agreement.

Multiple-Beam Detection of Fast Transient Radio Sources

NASA Technical Reports Server (NTRS)

Thompson, David R.; Wagstaff, Kiri L.; Majid, Walid A.

2011-01-01

A method has been designed for using multiple independent stations to discriminate fast transient radio sources from local anomalies, such as antenna noise or radio frequency interference (RFI). This can improve the sensitivity of incoherent detection for geographically separated stations such as the very long baseline array (VLBA), the future square kilometer array (SKA), or any other coincident observations by multiple separated receivers. The transients are short, broadband pulses of radio energy, often just a few milliseconds long, emitted by a variety of exotic astronomical phenomena. They generally represent rare, high-energy events making them of great scientific value. For RFI-robust adaptive detection of transients, using multiple stations, a family of algorithms has been developed. The technique exploits the fact that the separated stations constitute statistically independent samples of the target. This can be used to adaptively ignore RFI events for superior sensitivity. If the antenna signals are independent and identically distributed (IID), then RFI events are simply outlier data points that can be removed through robust estimation such as a trimmed or Winsorized estimator. The alternative "trimmed" estimator is considered, which excises the strongest n signals from the list of short-beamed intensities. Because local RFI is independent at each antenna, this interference is unlikely to occur at many antennas on the same step. Trimming the strongest signals provides robustness to RFI that can theoretically outperform even the detection performance of the same number of antennas at a single site. This algorithm requires sorting the signals at each time step and dispersion measure, an operation that is computationally tractable for existing array sizes. An alternative uses the various stations to form an ensemble estimate of the conditional density function (CDF) evaluated at each time step. Both methods outperform standard detection strategies on a test sequence of VLBA data, and both are efficient enough for deployment in real-time, online transient detection applications.

Acoustic stapedial reflexes in healthy neonates: normative data and test-retest reliability.

PubMed

Kei, Joseph

2012-01-01

The acoustic stapedial reflex (ASR) test provides useful information about the function of the auditory system. While it is frequently used with adults and children in a clinical setting, its use with young infants is limited. Presently, there are few data for neonates and inadequate research into the test-retest reliability of the ASR test. This study aimed to establish normative data and evaluate the test-retest reliability of the ASR test in healthy neonates. A cross-sectional experimental design was used to establish ASR normative data and assess the test-retest reliability of ASR thresholds obtained from healthy neonates. Sixty-eight full-term neonates with mean chronological age of 2.5 days (SD = 1.8 day), who passed the automated auditory brainstem response, transient evoked otoacoustic emission, and high frequency (1 kHz) tympanometry (HFT) tests. One randomly selected ear from each neonate was tested using TEOAE (transient evoked otoacoustic emission), HFT, and ASR tests using a 1 kHz probe tone. ASR thresholds were elicited by presenting pure tones of 0.5, 2, and 4 kHz and broadband noise (BBN) separately to the test ear in an ipsilateral stimulation mode. The ASR procedure was repeated to acquire retest data within the same testing session. Descriptive statistics, χ2, and analysis of variance with repeated measures tests were used to analyze ASR data. All neonates exhibited ASR when stimulated by tonal stimuli or BBN. The mean ASRTs (acoustic stapedial reflex thresholds) for the 0.5, 2, and 4 kHz tones were 81.6 ± 7.9, 71.3 ± 7.9, and 65.4 ± 8.7 dB HL, respectively. The mean ASRT for the BBN was estimated to be smaller than 57.2 dB HL, given the limitation of the equipment. The 95th percentiles of the ASRT were 95, 85, 80, and 75 dB HL for the 0.5, 2, and 4 kHz and BBN, respectively. The test-retest reliability of the ASR test for all stimuli was high, with no significant difference in mean ASRTs across the test and retest conditions. Test-retest differences were within 10 dB for more than 91% of ASRT data across all stimuli. There was a slight trend of ASRTs being more repeatable in the medium ASRT range than in the higher or lower range. This study demonstrated that ASRTs obtained from healthy neonates were highly repeatable across test and retest sessions. Given the availability of normative data and the high test-retest reliability, the ASR test will be useful as a diagnostic tool in a battery of tests to evaluate the auditory function of neonates. American Academy of Audiology.

Simulation of the transient processes of load rejection under different accident conditions in a hydroelectric generating set

NASA Astrophysics Data System (ADS)

Guo, W. C.; Yang, J. D.; Chen, J. P.; Peng, Z. Y.; Zhang, Y.; Chen, C. C.

2016-11-01

Load rejection test is one of the essential tests that carried out before the hydroelectric generating set is put into operation formally. The test aims at inspecting the rationality of the design of the water diversion and power generation system of hydropower station, reliability of the equipment of generating set and the dynamic characteristics of hydroturbine governing system. Proceeding from different accident conditions of hydroelectric generating set, this paper presents the transient processes of load rejection corresponding to different accident conditions, and elaborates the characteristics of different types of load rejection. Then the numerical simulation method of different types of load rejection is established. An engineering project is calculated to verify the validity of the method. Finally, based on the numerical simulation results, the relationship among the different types of load rejection and their functions on the design of hydropower station and the operation of load rejection test are pointed out. The results indicate that: The load rejection caused by the accident within the hydroelectric generating set is realized by emergency distributing valve, and it is the basis of the optimization for the closing law of guide vane and the calculation of regulation and guarantee. The load rejection caused by the accident outside the hydroelectric generating set is realized by the governor. It is the most efficient measure to inspect the dynamic characteristics of hydro-turbine governing system, and its closure rate of guide vane set in the governor depends on the optimization result in the former type load rejection.

Otoacoustic Emissions before and after Listening to Music on a Personal Player

PubMed Central

Trzaskowski, Bartosz; Jędrzejczak, W. Wiktor; Piłka, Edyta; Cieślicka, Magdalena; Skarżyński, Henryk

2014-01-01

Background The problem of the potential impact of personal music players on the auditory system remains an open question. The purpose of the present study was to investigate, by means of otoacoustic emissions (OAEs), whether listening to music on a personal player affected auditory function. Material/Methods A group of 20 normally hearing adults was exposed to music played on a personal player. Transient evoked OAEs (TEOAEs) and distortion product OAEs (DPOAEs), as well as pure tone audiometry (PTA) thresholds, were tested at 3 stages: before, immediately after, and the next day following 30 min of exposure to music at 86.6 dBA. Results We found no statistically significant changes in OAE parameters or PTA thresholds due to listening to the music. Conclusions These results suggest that exposure to music at levels similar to those used in our study does not disturb cochlear function in a way that can be detected by means of PTA, TEOAE, or DPOAE tests. PMID:25116920

Dichotic listening and otoacoustic emissions: shared variance between cochlear function and dichotic listening performance in adults with normal hearing.

PubMed

Markevych, Vladlena; Asbjørnsen, Arve E; Lind, Ola; Plante, Elena; Cone, Barbara

2011-07-01

The present study investigated a possible connection between speech processing and cochlear function. Twenty-two subjects with age range from 18 to 39, balanced for gender with normal hearing and without any known neurological condition, were tested with the dichotic listening (DL) test, in which listeners were asked to identify CV-syllables in a nonforced, and also attention-right, and attention-left condition. Transient evoked otoacoustic emissions (TEOAEs) were recorded for both ears, with and without the presentation of contralateral broadband noise. The main finding was a strong negative correlation between language laterality as measured with the dichotic listening task and of the TEOAE responses. The findings support a hypothesis of shared variance between central and peripheral auditory lateralities, and contribute to the attentional theory of auditory lateralization. The results have implications for the understanding of the cortico-fugal efferent control of cochlear activity. 2011 Elsevier Inc. All rights reserved.

On the Use of 3dB Qualification Margin for Structural Parts on Expendable Launch Vehicles

NASA Technical Reports Server (NTRS)

Yunis, Isam

2007-01-01

The standard random vibration qualification test used for Expendable Launch Vehicle components is Maximum Predicted Environment (MPE) + 6dB for a duration of 4 times the service life of the part. This can be a severe qualification test for these fatigue-sensitive structures. This paper uses flight data from several launch vehicles to establish that reducing the qualification approach to MPE+3dB for the duration of the peak environment (1x life) is valid for fatigue-sensitive structural components. Items that can be classified as fatigue-sensitive are probes, ducts, tubing, bellows, hoses, and any non-functional structure. Non-functional structure may be flight critical or carry fluid, but it cannot include any moving parts or electronics. This reduced qualification approach does not include primary or secondary structure which would be exclusively designed by peak loads, either transient or quasi-static, that are so large and of so few cycles as to make fatigue a moot point.

SCORE-EVET: a computer code for the multidimensional transient thermal-hydraulic analysis of nuclear fuel rod arrays. [BWR; PWR

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

Benedetti, R. L.; Lords, L. V.; Kiser, D. M.

1978-02-01

The SCORE-EVET code was developed to study multidimensional transient fluid flow in nuclear reactor fuel rod arrays. The conservation equations used were derived by volume averaging the transient compressible three-dimensional local continuum equations in Cartesian coordinates. No assumptions associated with subchannel flow have been incorporated into the derivation of the conservation equations. In addition to the three-dimensional fluid flow equations, the SCORE-EVET code ocntains: (a) a one-dimensional steady state solution scheme to initialize the flow field, (b) steady state and transient fuel rod conduction models, and (c) comprehensive correlation packages to describe fluid-to-fuel rod interfacial energy and momentum exchange. Velocitymore » and pressure boundary conditions can be specified as a function of time and space to model reactor transient conditions such as a hypothesized loss-of-coolant accident (LOCA) or flow blockage.« less

Radon inhalation protects against transient global cerebral ischemic injury in gerbils.

PubMed

Kataoka, Takahiro; Etani, Reo; Takata, Yuji; Nishiyama, Yuichi; Kawabe, Atsushi; Kumashiro, Masayuki; Taguchi, Takehito; Yamaoka, Kiyonori

2014-10-01

Although brain disorders are not the main indication for radon therapy, our previous study suggested that radon inhalation therapy might mitigate brain disorders. In this study, we assessed whether radon inhalation protects against transient global cerebral ischemic injury in gerbils. Gerbils were treated with inhaled radon at a concentration of 2,000 Bq/m(3) for 24 h. After radon inhalation, transient global cerebral ischemia was induced by bilateral occlusion of the common carotid artery. Results showed that transient global cerebral ischemia induced neuronal damage in hippocampal CA1, and the number of damaged neurons was significantly increased compared with control. However, radon treatment inhibited ischemic damage. Superoxide dismutase (SOD) activity in the radon-treated gerbil brain was significantly higher than that in sham-operated gerbils. These findings suggested that radon inhalation activates antioxidative function, especially SOD, thereby inhibiting transient global cerebral ischemic injury in gerbils.

Mapping the local protein interactome of the NuA3 histone acetyltransferase

PubMed Central

Smart, Sherri K; Mackintosh, Samuel G; Edmondson, Ricky D; Taverna, Sean D; Tackett, Alan J

2009-01-01

Protein–protein interactions modulate cellular functions ranging from the activity of enzymes to signal transduction cascades. A technology termed transient isotopic differentiation of interactions as random or targeted (transient I-DIRT) is described for the identification of stable and transient protein–protein interactions in vivo. The procedure combines mild in vivo chemical cross-linking and non-stringent affinity purification to isolate low abundance chromatin-associated protein complexes. Using isotopic labeling and mass spectrometric readout, purified proteins are categorized with respect to the protein ‘bait’ as stable, transient, or contaminant. Here we characterize the local interactome of the chromatin-associated NuA3 histone lysine-acetyltransferase protein complex. We describe transient associations with the yFACT nucleosome assembly complex, RSC chromatin remodeling complex and a nucleosome assembly protein. These novel, physical associations with yFACT, RSC, and Nap1 provide insight into the mechanism of NuA3-associated transcription and chromatin regulation. PMID:19621382

Preliminary tests of vulnerability of typical aircraft electronics to lightning-induced voltages

NASA Technical Reports Server (NTRS)

Plumer, J. A.; Walko, L. C.

1974-01-01

Tests made on two pieces of typical aircraft electronics equipment to ascertain their vulnerability to simulated lightning-induced transient voltages representative of those which might occur in flight when the aircraft is struck by lightning were conducted. The test results demonstrated that such equipment can be interfered with or damaged by transient voltages as low as 21 volts peak. Greater voltages can cause failure of semiconductor components within the equipment. The results emphasize a need for establishment of coordinated system susceptibility and component vulnerability criteria to achieve lightning protection of aerospace electrical and electronic systems.

Design, fabrication, and structural testing of a lightweight shadow shield for deep-space application

NASA Technical Reports Server (NTRS)

Miao, D.; Barber, J. R.; Dewitt, R. L.

1977-01-01

Two full-scale, lightweight, double-sheeted shadow shields were developed as the primary element of a deep-space thermal protection system for liquid-hydrogen propellant tankage. The thermal and mechanical considerations used in s, the method of fabrication, and the environmental testing results on a prototype shield are discussed. Testing consisted of a transient cooldown period, a prolonged cold soak, and a transient warmup. The mechanical and thermal analyses used in the shield design are sufficient to produce a lightweight rugged shadow shield assembly that is structurally adequate for its intended application.

A novel plant protection strategy for transient reactors

NASA Astrophysics Data System (ADS)

Bhattacharyya, Samit K.; Lipinski, Walter C.; Hanan, Nelson A.

The present plant protection system (PPS) has been defined for use in the TREAT-upgrade (TU) reactor for controlled transient operation of reactor-fuel behavior testing under simulated reactor-accident conditions. A PPS with energy-dependent trip set points lowered worst-case clad temperatures by as much as 180 K, relative to the use of conventional fixed-level trip set points. The multilayered multilevel protection strategy represents the state-of-the-art in terrestrial transient reactor protection systems, and should be applicable to multi-MW space reactors.

A theory of post-stall transients in axial compression systems. I - Development of equations

NASA Technical Reports Server (NTRS)

Moore, F. K.; Greitzer, E. M.

1985-01-01

An approximate theory is presented for post-stall transients in multistage axial compression systems. The theory leads to a set of three simultaneous nonlinear third-order partial differential equations for pressure rise, and average and disturbed values of flow coefficient, as functions of time and angle around the compressor. By a Galerkin procedure, angular dependence is averaged, and the equations become first order in time. These final equations are capable of describing the growth and possible decay of a rotating-stall cell during a compressor mass-flow transient. It is shown how rotating-stall-like and surgelike motions are coupled through these equations, and also how the instantaneous compressor pumping characteristic changes during the transient stall process.

Transient spatiotemporal chaos in the Morris-Lecar neuronal ring network.

PubMed

Keplinger, Keegan; Wackerbauer, Renate

2014-03-01

Transient behavior is thought to play an integral role in brain functionality. Numerical simulations of the firing activity of diffusively coupled, excitable Morris-Lecar neurons reveal transient spatiotemporal chaos in the parameter regime below the saddle-node on invariant circle bifurcation point. The neighborhood of the chaotic saddle is reached through perturbations of the rest state, in which few initially active neurons at an effective spatial distance can initiate spatiotemporal chaos. The system escapes from the neighborhood of the chaotic saddle to either the rest state or to a state of pulse propagation. The lifetime of the chaotic transients is manipulated in a statistical sense through a singular application of a synchronous perturbation to a group of neurons.

Power System Transient Stability Improvement by the Interline Power Flow Controller (IPFC)

NASA Astrophysics Data System (ADS)

Zhang, Jun; Yokoyama, Akihiko

This paper presents a study on the power system transient stability improvement by means of interline power flow controller (IPFC). The power injection model of IPFC in transient analysis is proposed and can be easily incorporated into existing power systems. Based on the energy function analysis, the operation of IPFC should guarantee that the time derivative of the global energy of the system is not greater than zero in order to damp the electromechanical oscillations. Accordingly, control laws of IPFC are proposed for its application to the single-machine infinite-bus (SMIB) system and the multimachine systems, respectively. Numerical simulations on the corresponding model power systems are presented to demonstrate their effectiveness in improving power system transient stability.

Analytical solution of the transient temperature profile in gain medium of passively Q-switched microchip laser.

PubMed

Han, Xiahui; Li, Jianlang

2014-11-01

The transient temperature evolution in the gain medium of a continuous wave (CW) end-pumped passively Q-switched microchip (PQSM) laser is analyzed. By approximating the time-dependent population inversion density as a sawtooth function of time and treating the time-dependent pump absorption of a CW end-pumped PQSM laser as the superposition of an infinite series of short pumping pulses, the analytical expressions of transient temperature evolution and distribution in the gain medium for four- and three-level laser systems, respectively, are given. These analytical solutions are applied to evaluate the transient temperature evolution and distribution in the gain medium of CW end-pumped PQSM Nd:YAG and Yb:YAG lasers.

Shear wave speed recovery in transient elastography and supersonic imaging using propagating fronts

NASA Astrophysics Data System (ADS)

McLaughlin, Joyce; Renzi, Daniel

2006-04-01

Transient elastography and supersonic imaging are promising new techniques for characterizing the elasticity of soft tissues. Using this method, an 'ultrafast imaging' system (up to 10 000 frames s-1) follows in real time the propagation of a low frequency shear wave. The displacement of the propagating shear wave is measured as a function of time and space. The objective of this paper is to develop and test algorithms whose ultimate product is images of the shear wave speed of tissue mimicking phantoms. The data used in the algorithms are the front of the propagating shear wave. Here, we first develop techniques to find the arrival time surface given the displacement data from a transient elastography experiment. The arrival time surface satisfies the Eikonal equation. We then propose a family of methods, called distance methods, to solve the inverse Eikonal equation: given the arrival times of a propagating wave, find the wave speed. Lastly, we explain why simple inversion schemes for the inverse Eikonal equation lead to large outliers in the wave speed and numerically demonstrate that the new scheme presented here does not have any large outliers. We exhibit two recoveries using these methods: one is with synthetic data; the other is with laboratory data obtained by Mathias Fink's group (the Laboratoire Ondes et Acoustique, ESPCI, Université Paris VII).

Transient pulse analysis of ionized electronics exposed to γ-radiation generated from a relativistic electron beam

NASA Astrophysics Data System (ADS)

Min, Sun-Hong; Kwon, Ohjoon; Sattorov, Matlabjon; Baek, In-Keun; Kim, Seontae; Hong, Dongpyo; Jeong, Jin-Young; Jang, Jungmin; Bera, Anirban; Barik, Ranjan Kumar; Bhattacharya, Ranajoy; Cho, Ilsung; Kim, Byungsu; Park, Chawon; Jung, Wongyun; Park, Seunghyuk; Park, Gun-Sik

2018-02-01

When a semiconductor element is irradiated with radiation in the form of a transient pulse emitted from a nuclear explosion, a large amount of charge is generated in a short time in the device. A photocurrent amplified in a certain direction by these types of charges cause the device to break down and malfunction or in extreme cases causes them to burn out. In this study, a pulse-type γ-ray generator based on a relativistic electron beam accelerator (γ=2.2, β=0.89) which functions by means of tungsten impingement was constructed and tested in an effort to investigate the process and effects of the photocurrent formed by electron hole pairs (EHP) generated in a pMOSFET device when a transient radiation pulse is incident in the device. The pulse-type γ-ray irradiating device used here to generate the electron beam current in a short time was devised to allow an increase in the irradiation dose. A precise signal processing circuit was constructed to measure the photocurrent of the small signal generated by the pMOSFET due to the electron beam accelerator pulse signal from the large noise stemming from the electromagnetic field around the relativistic electron beam accelerator. The pulse-type γ-ray generator was installed to meet the requirements of relativistic electron beam accelerators, and beam irradiation was conducted after a beam commissioning step.

Motivational effects on the processing of delayed intentions in the anterior prefrontal cortex.

PubMed

Bruening, Jovita; Ludwig, Vera U; Paschke, Lena M; Walter, Henrik; Stelzel, Christine

2018-05-15

Delaying intentions bears the risk of interference from distracting activities during the delay interval. Motivation can increase intention retrieval success but little is known about the underlying brain mechanisms. Here, we investigated whether motivational incentives (monetary reward) modulate the processing of delayed intentions in the anterior prefrontal cortex (aPFC), known to be crucial for intention processing. Using a mixed blocked and event-related functional Magnetic Resonance Imaging design, we specifically tested whether reward affects intention processing in the aPFC in a transient or in a sustained manner and whether this is related to individual differences in retrieval success. We found a generalized effect of reward on both correct intention retrieval and ongoing task performance. Fronto-parietal regions including bilateral lateral aPFC showed sustained activity increases in rewarded compared to non-rewarded blocks as well as transient reward-related activity during the storage phase. Additionally, individual differences in reward-related performance benefits were related to the degree of transient signal increases in right lateral aPFC, specifically during intention encoding. This suggests that the ability to integrate motivational relevance into the encoding of future intentions is crucial for successful intention retrieval in addition to general increases in processing effort. Bilateral aPFC is central to these motivation-cognition interactions. Copyright © 2018 Elsevier Inc. All rights reserved.

Temporal dependence of transient dark counts in an avalanche photodiode: A solution for power-law behavior of afterpulsing

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

Akiba, M., E-mail: akiba@nict.go.jp; Tsujino, K.

This paper offers a theoretical explanation of the temperature and temporal dependencies of transient dark count rates (DCRs) measured for a linear-mode silicon avalanche photodiode (APD) and the dependencies of afterpulsing that were measured in Geiger-mode Si and InGaAs/InP APDs. The temporal dependencies exhibit power-law behavior, at least to some extent. For the transient DCR, the value of the DCR for a given time period increases with decreases in temperature, while the power-law behavior remains unchanged. The transient DCR is attributed to electron emissions from traps in the multiplication layer of the APD with a high electric field, and itsmore » temporal dependence is explained by a continuous change in the electron emission rate as a function of the electric field strength. The electron emission rate is calculated using a quantum model for phonon-assisted tunnel emission. We applied the theory to the temporal dependence of afterpulsing that was measured for Si and InGaAs/InP APDs. The power-law temporal dependence is attributed to the power-law function of the electron emission rate from the traps as a function of their position across the p–n junction of the APD. Deviations from the power-law temporal dependence can be derived from the upper and lower limits of the electric field strength.« less

Some exact properties of the nonequilibrium response function for transient photoabsorption

NASA Astrophysics Data System (ADS)

Perfetto, E.; Stefanucci, G.

2015-03-01

The physical interpretation of time-resolved photoabsorption experiments is not as straightforward as for the more conventional photoabsorption experiments conducted on equilibrium systems. In fact, the relation between the transient photoabsorption spectrum and the properties of the examined sample can be rather intricate since the former is a complicated functional of both the driving pump and the feeble probe fields. In this work, we critically review the derivation of the time-resolved photoabsorption spectrum in terms of the nonequilibrium dipole response function χ and assess its domain of validity. We then analyze χ in detail and discuss a few exact properties useful to interpret the transient spectrum during (overlapping regime) and after (nonoverlapping regime) the action of the pump. The nonoverlapping regime is the simplest to address. The absorption energies are indeed independent of the delay between the pump and probe pulses and hence the transient spectrum can change only by a rearrangement of the spectral weights. We give a close expression of these spectral weights in two limiting cases (ultrashort and everlasting monochromatic probes) and highlight their strong dependence on coherence and probe envelope. In the overlapping regime, we obtain a Lehmann-type representation of χ in terms of light-dressed states and provide a unifying framework of various well-known effects in pump-driven systems. We also show the emergence of spectral substructures due to the finite duration of the pump pulse.

Transient decrease in nociceptor GRK2 expression produces long–term enhancement in inflammatory pain

PubMed Central

Ferrari, Luiz F.; Bogen, Oliver; Alessandri–Haber, Nicole; Levine, Emma; Gear, Robert W.; Levine, Jon D.

2012-01-01

In heterozygous mice, attenuation of G-protein-coupled receptor kinase 2 (GRK2) level in nociceptors is associated with enhanced and prolonged inflammatory hyperalgesia. To further elucidate the role of GRK2 in nociceptor function we reversibly decreased GRK2 expression using intrathecal antisense oligodeoxynucleotide (AS-ODN). GRK2 AS-ODN administration led to an enhanced and prolonged hyperalgesia induced by prostaglandin E 2, epinephrine and carrageenan. Morover, this effect persisted unattenuated 2 weeks after the last dose of antisense, well after GRK2 protein recovered, suggesting that transient attenuation of GRK2 produced neuroplastic changes in nociceptor function. Unlike hyperalgesic priming induced by transient attenuation of GRK2 produced neuroplastic changes in nociceptor function. Unlike hyperalgesic priming induced by transient activation of protein kinase C epsilon (PKCε), (Aley et al., 2000, Parada et al., 2003b), the enhanced and prolonged hyperalgesia following attenuation of GRK2 is PKCε- and cytoplasmic polyadenylation element binding protein (CPEB)-independent and is protein kinase A (PKA)- and Src tyrosine kinase (Src)-dependent. Finally, rats treated with GRK2 AS-ODN exhibited enhanced and prolonged hyperalgesia induced by direct activation of second messengers, adenyl cyclase, Epac or PKA, suggesting changes downstream of G-protein-coupled receptors. Because inflammation can produce a decrease in GRK2, such a mechanism could help explain a predilection to develop chronic pain, after resolution of acute inflammation. PMID:22796071

An analysis of transient flow in upland watersheds: interactions between structure and process

Treesearch

David Lawrence Brown

1995-01-01

The physical structure and hydrological processes of upland watersheds interact in response to forcing functions such as rainfall, leading to storm runoff generation and pore pressure evolution. Transient fluid flow through distinct flow paths such as the soil matrix, macropores, saprolite, and bedrock may be viewed as a consequence of such interactions. Field...

Evaluation of a multi-channel algorithm for reducing transient sounds.

PubMed

Keshavarzi, Mahmoud; Baer, Thomas; Moore, Brian C J

2018-05-15

The objective was to evaluate and select appropriate parameters for a multi-channel transient reduction (MCTR) algorithm for detecting and attenuating transient sounds in speech. In each trial, the same sentence was played twice. A transient sound was presented in both sentences, but its level varied across the two depending on whether or not it had been processed by the MCTR and on the "strength" of the processing. The participant indicated their preference for which one was better and by how much in terms of the balance between the annoyance produced by the transient and the audibility of the transient (they were told that the transient should still be audible). Twenty English-speaking participants were tested, 10 with normal hearing and 10 with mild-to-moderate hearing-impairment. Frequency-dependent linear amplification was provided for the latter. The results for both participant groups indicated that sounds processed using the MCTR were preferred over the unprocessed sounds. For the hearing-impaired participants, the medium and strong settings of the MCTR were preferred over the weak setting. The medium and strong settings of the MCTR reduced the annoyance produced by the transients while maintaining their audibility.

Recurrence of random walks with long-range steps generated by fractional Laplacian matrices on regular networks and simple cubic lattices

NASA Astrophysics Data System (ADS)

Michelitsch, T. M.; Collet, B. A.; Riascos, A. P.; Nowakowski, A. F.; Nicolleau, F. C. G. A.

2017-12-01

We analyze a Markovian random walk strategy on undirected regular networks involving power matrix functions of the type L\\frac{α{2}} where L indicates a ‘simple’ Laplacian matrix. We refer to such walks as ‘fractional random walks’ with admissible interval 0<α ≤slant 2 . We deduce probability-generating functions (network Green’s functions) for the fractional random walk. From these analytical results we establish a generalization of Polya’s recurrence theorem for fractional random walks on d-dimensional infinite lattices: The fractional random walk is transient for dimensions d > α (recurrent for d≤slantα ) of the lattice. As a consequence, for 0<α< 1 the fractional random walk is transient for all lattice dimensions d=1, 2, .. and in the range 1≤slantα < 2 for dimensions d≥slant 2 . Finally, for α=2 , Polya’s classical recurrence theorem is recovered, namely the walk is transient only for lattice dimensions d≥slant 3 . The generalization of Polya’s recurrence theorem remains valid for the class of random walks with Lévy flight asymptotics for long-range steps. We also analyze the mean first passage probabilities, mean residence times, mean first passage times and global mean first passage times (Kemeny constant) for the fractional random walk. For an infinite 1D lattice (infinite ring) we obtain for the transient regime 0<α<1 closed form expressions for the fractional lattice Green’s function matrix containing the escape and ever passage probabilities. The ever passage probabilities (fractional lattice Green’s functions) in the transient regime fulfil Riesz potential power law decay asymptotic behavior for nodes far from the departure node. The non-locality of the fractional random walk is generated by the non-diagonality of the fractional Laplacian matrix with Lévy-type heavy tailed inverse power law decay for the probability of long-range moves. This non-local and asymptotic behavior of the fractional random walk introduces small-world properties with the emergence of Lévy flights on large (infinite) lattices.

Transient neonatal hypothyroidism due to a maternal vegan diet.

PubMed

Shaikh, M G; Anderson, J M; Hall, S K; Jackson, M A

2003-01-01

Iodine is an important constituent of thyroid hormones and deficiency can lead to a range of problems depending on the degree and at what stage of life the deficiency occurs. We report a 10 day-old infant with a goitre, who presented with raised TSH on dried blood spot screening. It was observed that her mother also had a goitre. The mother was a vegan and, on dietary assessment, her iodine intake was extremely low. Both mother and infant had abnormal thyroid function tests. Mother was given Lugol's iodine and her thyroid function tests normalised. Her baby was initially prescribed thyroxine on the basis of the raised screening TSH. This was subsequently withdrawn at the age of 2 weeks, following a normal plasma TSH. Thyroid function tests remained normal and the goitre disappeared by the age of 2 months. Iodine deficiency is uncommon in the Western World. However the incidence may be rising in otherwise iodine replete areas, particularly in those who adhere to restrictive and unusual diets. In the case of pregnant mothers their unborn child's health is in danger. This report demonstrates the need to ascertain maternal diets early in antenatal care, and supplement if necessary to avoid risk to their own health and that of their offspring.

Space-time analysis of Down syndrome: results consistent with transient pre-disposing contagious agent.

PubMed

McNally, Richard J Q; Rankin, Judith; Shirley, Mark D F; Rushton, Stephen P; Pless-Mulloli, Tanja

2008-10-01

Whilst maternal age is an established risk factor for Patau syndrome (trisomy 13), Edwards syndrome (trisomy 18) and Down syndrome (trisomy 21), the aetiology and contribution of genetic and environmental factors remains unclear. We analysed for space-time clustering using high quality fully population-based data from a geographically defined region. The study included all cases of Patau, Edwards and Down syndrome, delivered during 1985-2003 and resident in the former Northern Region of England, including terminations of pregnancy for fetal anomaly. We applied the K-function test for space-time clustering with fixed thresholds of close in space and time using residential addresses at time of delivery. The Knox test was used to indicate the range over which the clustering effect occurred. Tests were repeated using nearest neighbour (NN) thresholds to adjust for variable population density. The study analysed 116 cases of Patau syndrome, 240 cases of Edwards syndrome and 1084 cases of Down syndrome. There was evidence of space-time clustering for Down syndrome (fixed threshold of close in space: P = 0.01, NN threshold: P = 0.02), but little or no clustering for Patau (P = 0.57, P = 0.19) or Edwards (P = 0.37, P = 0.06) syndromes. Clustering of Down syndrome was associated with cases from more densely populated areas and evidence of clustering persisted when cases were restricted to maternal age <40 years. The highly novel space-time clustering for Down syndrome suggests an aetiological role for transient environmental factors, such as infections.

Progesterone Treatment in Two Rat Models of Ocular Ischemia

PubMed Central

Allen, Rachael S.; Olsen, Timothy W.; Sayeed, Iqbal; Cale, Heather A.; Morrison, Katherine C.; Oumarbaeva, Yuliya; Lucaciu, Irina; Boatright, Jeffrey H.; Pardue, Machelle T.; Stein, Donald G.

2015-01-01

Purpose. To determine whether the neurosteroid progesterone, shown to have protective effects in animal models of traumatic brain injury, stroke, and spinal cord injury, is also protective in ocular ischemia animal models. Methods. Progesterone treatment was tested in two ocular ischemia models in rats: a rodent anterior ischemic optic neuropathy (rAION) model, which induces permanent monocular optic nerve stroke, and the middle cerebral artery occlusion (MCAO) model, which causes transient ischemia in both the retina and brain due to an intraluminal filament that blocks the ophthalmic and middle cerebral arteries. Visual function and retinal histology were assessed to determine whether progesterone attenuated retinal injury in these models. Additionally, behavioral testing and 2% 2,3,5-triphenyltetrazolium chloride (TTC) staining in brains were used to compare progesterone's neuroprotective effects in both retina and brain using the MCAO model. Results. Progesterone treatment showed no effect on visual evoked potential (VEP) reduction and retinal ganglion cell loss in the permanent rAION model. In the transient MCAO model, progesterone treatment reduced (1) electroretinogram (ERG) deficits, (2) MCAO-induced upregulation of glutamine synthetase (GS) and glial fibrillary acidic protein (GFAP), and (3) retinal ganglion cell loss. As expected, progesterone treatment also had significant protective effects in behavioral tests and a reduction in infarct size in the brain. Conclusions. Progesterone treatment showed protective effects in the retina following MCAO but not rAION injury, which may result from mechanistic differences with injury type and the therapeutic action of progesterone. PMID:26024074

Analysis of Spontaneous and Nerve-Evoked Calcium Transients in Intact Extraocular Muscles in Vitro

PubMed Central

Feng, Cheng-Yuan; Hennig, Grant W.; Corrigan, Robert D.; Smith, Terence K.; von Bartheld, Christopher S.

2012-01-01

Extraocular muscles (EOMs) have unique calcium handling properties, yet little is known about the dynamics of calcium events underlying ultrafast and tonic contractions in myofibers of intact EOMs. Superior oblique EOMs of juvenile chickens were dissected with their nerve attached, maintained in oxygenated Krebs buffer, and loaded with fluo-4. Spontaneous and nerve stimulation-evoked calcium transients were recorded and, following calcium imaging, some EOMs were double-labeled with rhodamine-conjugated alpha-bungarotoxin (rhBTX) to identify EOM myofiber types. EOMs showed two main types of spontaneous calcium transients, one slow type (calcium waves with 1/2max duration of 2–12 s, velocity of 25–50 μm/s) and two fast “flash-like” types (Type 1, 30–90 ms; Type 2, 90–150 ms 1/2max duration). Single pulse nerve stimulation evoked fast calcium transients identical to the fast (Type 1) calcium transients. Calcium waves were accompanied by a local myofiber contraction that followed the calcium transient wavefront. The magnitude of calcium-wave induced myofiber contraction far exceeded those of movement induced by nerve stimulation and associated fast calcium transients. Tetrodotoxin eliminated nerve-evoked transients, but not spontaneous transients. Alpha-bungarotoxin eliminated both spontaneous and nerve-evoked fast calcium transients, but not calcium waves, and caffeine increased wave activity. Calcium waves were observed in myofibers lacking spontaneous or evoked fast transients, suggestive of multiply-innervated myofibers, and this was confirmed by double-labeling with rhBTX. We propose that the abundant spontaneous calcium transients and calcium waves with localized contractions that do not depend on innervation may contribute to intrinsic generation of tonic functions of EOMs. PMID:22579493

Use of thromboelastography to tailor dual-antiplatelet therapy in patients undergoing treatment of intracranial aneurysms with the Pipeline embolization device.

PubMed

McTaggart, Ryan A; Choudhri, Omar A; Marcellus, Mary L; Brennan, Tom; Steinberg, Gary K; Dodd, Robert L; Do, Huy M; Marks, Michael P

2015-06-01

Platelet function testing is controversial and not well studied in patients with neurovascular disease. To evaluate the performance of thromboelastography (TEG) as a platelet function test in neurovascular patients treated with the Pipeline embolization device (PED). A prospective protocol was instituted for platelet function testing in patients undergoing repair of intracranial aneurysms with the PED. All patients received dual antiplatelet therapy (DAT) and their response to both P2Y12 inhibitors and aspirin was quantified with TEG. Each patient's DAT induction strategy was tailored based on the percentage ADP-induced and percentage arachidonic acid-induced platelet inhibition reported by TEG. Data collected included clinical presentation, aneurysm characteristics, treatment details, and periprocedural events. Patients were followed up clinically and/or angiographically at 30 days, 6 months, and 1 year. Thirty-four PED procedures were performed on 31 patients. TEG results altered the DAT strategy in 35% of patients. Technical success with the Pipeline placement was 100%. Two patients had minor strokes and five had transient ischemic attacks (TIAs). There have been no hemorrhagic complications. No patient had permanent neurologic deficits. Six of eight (75%) of patients with thromboembolic/TIA events were ADP-induced hyporesponders by TEG. Our 6- and 12-month angiographic occlusion rates were 78.9% and 89.5%, respectively. The 19 major branches covered by the PED that were assessed by follow-up imaging have all remained patent. Platelet function testing with TEG altered our DAT induction strategy in a significant number of cases. No hemorrhagic or disabling thromboembolic complications were seen in this series. Future studies should compare methods of platelet function testing and, possibly, no platelet function testing in neurovascular patients undergoing flow diversion and/or stent-assisted treatment of intracranial aneurysms. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Rural Transient Children and School Achievement: An Australian Perspective.

ERIC Educational Resources Information Center

Birch, Ian; Lally, Mike

1994-01-01

Among 336 students aged 4-8 in 4 rural Australian schools, transient students scored marginally lower on ability tests than their residentially stable peers. However, teachers gave more weight to family background and support, as opposed to disruption of schooling, as influencing children's adjustment to change and school achievement. (LP)

40 CFR 86.1333-2010 - Transient test cycle generation.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate... cycles. The heavy-duty transient engine cycles for Otto-cycle and diesel engines are listed in appendix I...

40 CFR 86.1333-2010 - Transient test cycle generation.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate... cycles. The heavy-duty transient engine cycles for Otto-cycle and diesel engines are listed in appendix I...

40 CFR 86.1333-2010 - Transient test cycle generation.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate... cycles. The heavy-duty transient engine cycles for Otto-cycle and diesel engines are listed in appendix I...

Transient hypoxia stimulates mitochondrial biogenesis in brain subcortex by a neuronal nitric oxide synthase-dependent mechanism

EPA Science Inventory

The adaptive mechanisms that protect brain metabolism during and after hypoxia, for instance, during hypoxic preconditioning, are coordinated in part by nitric oxide (NO). We tested the hypothesis that acute transient hypoxia stimulates NO synthase (NOS)-activated mechanisms of m...

Inhalational mold toxicity: fact or fiction? A clinical review of 50 cases.

PubMed

Khalili, Barzin; Montanaro, Marc T; Bardana, Emil J

2005-09-01

Three well-accepted mechanisms of mold-induced disease exist: allergy, infection, and oral toxicosis. Epidemiologic studies suggest a fourth category described as a transient aeroirritation effect. Toxic mold syndrome or inhalational toxicity continues to cause public concern despite a lack of scientific evidence that supports its existence. To conduct a retrospective review of 50 cases of purported mold-induced toxic effects and identify unrecognized conditions that could explain presenting symptoms; to characterize a subgroup with a symptom complex suggestive of an aeroirritation-mediated mechanism and compare this group to other diagnostic categories, such as sick building syndrome and idiopathic chemical intolerance; and to discuss the evolution of toxic mold syndrome from a clinical perspective. Eighty-two consecutive medical evaluations were analyzed of which 50 met inclusion criteria. These cases were critically reviewed and underwent data extraction of 23 variables, including demographic data, patient symptoms, laboratory, imaging, and pulmonary function test results, and an evaluation of medical diagnoses supported by medical record review, examination, and/or test results. Upper respiratory tract, lower respiratory tract, systemic, and neurocognitive symptoms were reported in 80%, 94%, 74%, and 84% of patients, respectively. Thirty patients had evidence of non-mold-related conditions that explained their presenting complaints. Two patients had evidence of allergy to mold allergens, whereas 1 patient exhibited mold-induced psychosis best described as toxic agoraphobia. Seventeen patients displayed a symptom complex that could be postulated to be caused by a transient mold-induced aeroirritation. The clinical presentation of patients with perceived mold-induced toxic effects is characterized by a disparate constellation of symptoms. Close scrutiny revealed a number of preexisting diagnoses that could plausibly explain presenting symptoms. The pathogenesis of aeroirritation implies completely transient symptoms linked to exposures at the incriminated site. Toxic mold syndrome represents the furtive evolution of aeroirritation from a transient to permanent symptom complex in patients with a psychogenic predisposition. In this respect, the core symptoms of toxic mold syndrome and their gradual transition to chronic symptoms related to nonspecific environmental fragrances and irritants appear to mimic what has been observed with other pseudodiagnostic categories, such as sick building syndrome and idiopathic chemical intolerance.

Pretest analysis document for Test S-FS-7

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

Hall, D.G.

This report documents the pretest calculations completed for Semiscale Test S-FS-7. This test will simulate a transient initiated by a 14.3% break in a steam generator bottom feedwater line downstream of the check valve. The initial conditions represent normal operating conditions for a C-E System 80 nuclear power plant. Predictions of transients resulting from feedwater line breaks in these plants have indicated that significant primary system overpressurization may occur. The results of a RELAP5/MOD2/CY21 code calculation indicate that the test objectives for Test S-FS-7 can be achieved. The primary system overpressurization will occur but pose no threat to personnel ormore » to plant integrity. 3 refs., 15 figs., 5 tabs.« less

Pretest analysis document for Test S-FS-11

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

Hall, D.G.; Shaw, R.A.

This report documents the pretest calculations completed for Semiscale Test S-FS-11. This test will simulate a transient initiated by a 50% break in a steam generator bottom feedwater line downstream of the check valve. The initial conditions represents normal operating conditions for a C-E System 80 nuclear plant. Prediction of transients resulting from feedwater line breaks in these plants have indicated that significant primary system overpressurization may occur. The results of a RELAP5/MOD2/CY21 code calculation indicate that the test objectives for Test S-FS-11 can be achieved. The primary system overpressurization will occur but pose no threat to personnel or plantmore » integrity. 3 refs., 15 figs., 5 tabs.« less

Augmentor transient capability of an F100 engine equipped with a digital electronic engine control

NASA Technical Reports Server (NTRS)

Burcham, F. W., Jr.; Pai, G. D.

1984-01-01

An F100 augmented turbofan engine equipped with digital electronic engine control (DEEC) system was evaluated. The engine was equipped with a specially modified augmentor to provide improved steady state and transient augmentor capability. The combination of the DEEC and the modified augmentor was evaluated in sea level and altitude facility tests and then in four different flight phases in an F-15 aircraft. The augmentor configuration, logic, and test results are presented.

SSME turbopump technology improvements via transient rotordynamic analysis

NASA Technical Reports Server (NTRS)

Childs, D. W.

1975-01-01

The rotordynamic behavior of the high pressure oxygen turbopump and high pressure fuel pump was analyzed for the Space Shuttle Main Engine. The identification of potential rotordynamic problem areas which might arise during operation of these units prior to their testing was accomplished. Alternative procedures for correcting potential rotordynamic problems should they occur were investigated. An adequate analytic and physical understanding of the turbopump rotordynamics was developed to improve the probability of a correct diagnosis of rotordynamic problems from test data. Transient rotordynamic models were developed for both turbopumps. The transient models model the hydrodynamic forces of the turbopump seals. A linear stability analysis was performed for the turbopump rotordynamics models, which included gyroscopic effects, seal forces, speed-dependent bearing characteristics, and internal rotor damping. Results are presented and discussed.

Transient neonatal myasthenia gravis due to a mother with ocular onset of anti-muscle specific kinase myasthenia gravis.

PubMed

Lee, Ju-Yeun; Min, Ju-Hong; Han, Sueng-Han; Han, Jinu

2017-07-01

We describe a 27-year-old pregnant female with new onset of conjugate gaze deficit during the third trimester of pregnancy. Repetitive nerve stimulation tests, neostigmine tests, and acetylcholine receptor antibody assays were all negative. The patient delivered a normal healthy baby at a local clinic via cesarean section. The baby became hypotonic and had respiratory failure several minutes after birth. The result of acetylcholine receptor antibody was negative in the neonate. The neonate became healthy spontaneously and was extubated after 21 days of ventilation care. Two months after delivery, the mother developed ptosis and generalized symptoms and subsequent workup revealed she was muscle specific kinase (MuSK) antibody positive. The neonate was presumed to have an anti-MuSK-mediated transient neonatal myasthenia gravis. Although MuSK antibody testing is rarely indicated in ocular myasthenia gravis, MuSK antibody testing is necessary in pregnant women who are presumed ocular myasthenia gravis to warn occurrence of transient neonatal myasthenia gravis. Copyright © 2017 Elsevier B.V. All rights reserved.

Experimental study of transient liquid motion in orbiting spacecraft

NASA Technical Reports Server (NTRS)

Berry, R. L.; Tegart, J. R.

1975-01-01

The results are presented of a twofold study of transient liquid motion such as that which will be experienced during orbital maneuvers by space tug. A test program was conducted in a low-g test facility involving twenty-two drops. Biaxial, low-g accelerations were applied to an instrumented, model propellant tank during free-fall testing, and forces exerted during liquid reorientation were measured and recorded. Photographic records of the liquid reorientation were also made. The test data were used to verify a mechanical analog which portrays the liquid as a point mass moving on an ellipsoidal constraint surface. The mechanical analog was coded into a FORTRAN IV digital computer program: LAMPS, Large AMPlitude Slosh. Test/analytical correlation indicates that the mechanical analog is capable of predicting the overall force trends measured during testing.

Effects of angiotensin-converting enzyme inhibition on transient ischemia: the Quinapril Anti-Ischemia and Symptoms of Angina Reduction (QUASAR) trial.

PubMed

Pepine, Carl J; Rouleau, Jean-Lucien; Annis, Karen; Ducharme, Anique; Ma, Patrick; Lenis, Jacques; Davies, Richard; Thadani, Udho; Chaitman, Bernard; Haber, Harry E; Freedman, S Ben; Pressler, Milton L; Pitt, Bertram

2003-12-17

We sought to determine whether angiotensin-converting enzyme inhibition (ACE-I) (i.e., quinapril) prevents transient ischemia (exertional and spontaneous) in patients with coronary artery disease (CAD). It is known that ACE-I reduces the risk of death, myocardial infarction (MI), and other CAD-related outcomes in high-risk patients. Numerous studies have confirmed that ACE-I improves coronary flow and endothelial function. Whether ACE-I also decreases transient ischemia is unclear, because no studies have been adequately designed or sufficiently powered to evaluate this issue. Using a randomized, double-blinded, placebo-controlled, multicenter design, we enrolled 336 CAD patients with stable angina. None had uncontrolled hypertension, left ventricular (LV) dysfunction, or recent MI, and all developed electrocardiographic (ECG) evidence of ischemia during exercise. They were randomly assigned to one of two groups: 40 mg/day quinapril (n = 177) or placebo (n = 159) for 8 weeks. Patients then entered an additional eight-week treatment phase to examine the full dose range. Those assigned to 40 mg quinapril continued that dose and those assigned to placebo were titrated to 80 mg/day. Treadmill testing, the Seattle Angina Questionnaire, and ambulatory ECG monitoring were used to assess responses at baseline and at 8 and 16 weeks. The groups did not differ significantly at entry or in terms of indexes assessing myocardial ischemia at 8 or 16 weeks of treatment. In this low-risk population, ACE-I was not associated with serious adverse events. Our findings suggest short-term ACE-I in CAD patients without hypertension, LV dysfunction, or acute MI is not associated with significant effects on transient ischemia.

Physiological response of cardiac tissue to bisphenol a: alterations in ventricular pressure and contractility

PubMed Central

Brooks, Daina; Chandra, Akhil; Jaimes, Rafael; Sarvazyan, Narine; Kay, Matthew

2015-01-01

Biomonitoring studies have indicated that humans are routinely exposed to bisphenol A (BPA), a chemical that is commonly used in the production of polycarbonate plastics and epoxy resins. Epidemiological studies have shown that BPA exposure in humans is associated with cardiovascular disease; however, the direct effects of BPA on cardiac physiology are largely unknown. Previously, we have shown that BPA exposure slows atrioventricular electrical conduction, decreases epicardial conduction velocity, and prolongs action potential duration in excised rat hearts. In the present study, we tested if BPA exposure also adversely affects cardiac contractile performance. We examined the impact of BPA exposure level, sex, and pacing rate on cardiac contractile function in excised rat hearts. Hearts were retrogradely perfused at constant pressure and exposed to 10−9-10−4 M BPA. Left ventricular developed pressure and contractility were measured during sinus rhythm and during pacing (5, 6.5, and 9 Hz). Ca2+ transients were imaged from whole hearts and from neonatal rat cardiomyocyte layers. During sinus rhythm in female hearts, BPA exposure decreased left ventricular developed pressure and inotropy in a dose-dependent manner. The reduced contractile performance was exacerbated at higher pacing rates. BPA-induced effects on contractile performance were also observed in male hearts, albeit to a lesser extent. Exposure to BPA altered Ca2+ handling within whole hearts (reduced diastolic and systolic Ca2+ transient potentiation) and neonatal cardiomyocytes (reduced Ca2+ transient amplitude and prolonged Ca2+ transient release time). In conclusion, BPA exposure significantly impaired cardiac performance in a dose-dependent manner, having a major negative impact upon electrical conduction, intracellular Ca2+ handing, and ventricular contractility. PMID:25980024

Transient Response to Rapid Cooling of a Stainless Steel Sodium Heat Pipe

NASA Technical Reports Server (NTRS)

Mireles, Omar R.; Houts, Michael G.

2011-01-01

Compact fission power systems are under consideration for use in long duration space exploration missions. Power demands on the order of 500 W, to 5 kW, will be required for up to 15 years of continuous service. One such small reactor design consists of a fast spectrum reactor cooled with an array of in-core alkali metal heat pipes coupled to thermoelectric or Stirling power conversion systems. Heat pipes advantageous attributes include a simplistic design, lack of moving parts, and well understood behavior. Concerns over reactor transients induced by heat pipe instability as a function of extreme thermal transients require experimental investigations. One particular concern is rapid cooling of the heat pipe condenser that would propagate to cool the evaporator. Rapid cooling of the reactor core beyond acceptable design limits could possibly induce unintended reactor control issues. This paper discusses a series of experimental demonstrations where a heat pipe operating at near prototypic conditions experienced rapid cooling of the condenser. The condenser section of a stainless steel sodium heat pipe was enclosed within a heat exchanger. The heat pipe - heat exchanger assembly was housed within a vacuum chamber held at a pressure of 50 Torr of helium. The heat pipe was brought to steady state operating conditions using graphite resistance heaters then cooled by a high flow of gaseous nitrogen through the heat exchanger. Subsequent thermal transient behavior was characterized by performing an energy balance using temperature, pressure and flow rate data obtained throughout the tests. Results indicate the degree of temperature change that results from a rapid cooling scenario will not significantly influence thermal stability of an operating heat pipe, even under extreme condenser cooling conditions.

Frequency of Inverted Electrocardiographic T Waves (Cerebral T Waves) in Patients With Acute Strokes and Their Relation to Left Ventricular Wall Motion Abnormalities.

PubMed

Stone, Jeremy; Mor-Avi, Victor; Ardelt, Agnieszka; Lang, Roberto M

2018-01-01

Transient, symmetric, and deep inverted electrocardiogram (ECG) T waves in the setting of stroke, commonly referred to as cerebral T waves, are rare, and the underlying mechanism is unclear. Our study aimed to test the hypothesis that cerebral T waves are associated with transient cardiac dysfunction. This retrospective study included 800 patients admitted with the primary diagnosis of hemorrhagic or ischemic stroke. ECGs were examined for cerebral T waves, defined as T-wave inversion of ≥5 mm depth in ≥4 contiguous precordial leads. Echocardiograms of those meeting these criteria were examined for the presence of left ventricular (LV) wall motion abnormalities. Follow-up evaluation included both ECG and echocardiogram. Of the 800 patients, 17 had cerebral T waves on ECG (2.1%). All 17 patients had ischemic strokes, of which 11 were in the middle cerebral artery distribution (65%), and 2 were cerebellar (12%), whereas the remaining 4 involved other locations. Follow-up ECG showed resolution of the T-wave changes in all 17 patients. Of these patients, 14 (82%) had normal wall motion, and 3 had transient wall motion abnormalities (18%). Two of these patients had Takotsubo-like cardiomyopathy with apical ballooning, and the third had globally reduced LV function. Coronary angiography showed no significant disease to explain the LV dysfunction. In summary, in our cohort of patients with acute stroke, cerebral T waves were rare and occurred only in ischemic stroke. Eighteen percent of patients with cerebral T waves had significant transient wall motion abnormalities. Patients with stroke with cerebral T waves, especially in those with ischemic strokes, should be assessed for cardiac dysfunction. Copyright © 2017 Elsevier Inc. All rights reserved.

Cerebrovascular blood pressure autoregulation monitoring and postoperative transient ischemic attack in pediatric moyamoya vasculopathy.

PubMed

Lee, Jennifer K; Williams, Monica; Reyes, Michael; Ahn, Edward S

2018-02-01

Children with moyamoya vasculopathy are at high risk of perioperative cerebral ischemia or hyperperfusion. Maintaining blood pressure within the range of functional cerebrovascular blood pressure autoregulation might reduce the risk of perioperative neurologic injury. We tested whether blood pressure autoregulation is associated with postoperative transient ischemic attack in a study of patients with pediatric moyamoya vasculopathy. We conducted an observational study of 15 pediatric patients undergoing surgical revascularization with pial synangiosis. Nine patients had bilateral moyamoya and 6 had unilateral moyamoya. We measured autoregulatory vasoreactivity intraoperatively and during the first postoperative night with the hemoglobin volume index, a value derived from near-infrared spectroscopy. We also identified the optimal mean arterial blood pressure at which autoregulation was most robust in each patient. Of the 15 children monitored, 3 with bilateral moyamoya and one with unilateral moyamoya experienced a transient ischemic attack. Poorer autoregulation during surgery was associated with postoperative transient ischemic attack among those with bilateral vasculopathy (P = .048, difference in hemoglobin volume index medians: 0.023, 95% confidence interval: 0.003-0.071). This relationship was not observed with postoperative autoregulation. The optimal mean arterial blood pressure was identifiable during surgery in all monitored patients, varied among patients, and often differed between the intraoperative and postoperative periods. Dysfunctional intraoperative autoregulation may increase the risk of TIA in patients with pediatric moyamoya vasculopathy. The blood pressure range that supports autoregulation appears to vary among patients. Using autoregulation monitoring to guide individualized blood pressure goals should be studied as a potential method to reduce perioperative neurologic morbidity in pediatric patients with moyamoya. © 2017 John Wiley & Sons Ltd.

Advanced Fuel Cycle Technology: Special Session in Honor of Dr. Michael Lineberry

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

D.M. Wachs; N. Woolstenhulme

2014-06-01

The US DOE recently initiated an effort to develop accident tolerant fuel designs for potential use in commercial power reactors. Evaluation of various fuel design concepts will require a broad array of testing that will include performance attributes at both steady state and transient irradiation conditions. The first stage of the transient testing program is intended to establish the relative performance limits of each proposed concept and to support development of first-draft fuel performance models. It is anticipated that this data can subsequently be used as the basis for larger scale qualification testing. This initial stage of the testing programmore » is outlined in this paper.« less

Enantioselective remote meta-C-H arylation and alkylation via a chiral transient mediator.

PubMed

Shi, Hang; Herron, Alastair N; Shao, Ying; Shao, Qian; Yu, Jin-Quan

2018-06-18

Enantioselective carbon-hydrogen (C-H) activation reactions by asymmetric metallation could provide new routes for the construction of chiral molecules 1,2 . However, current methods are typically limited to the formation of five- or six-membered metallacycles, thereby preventing the asymmetric functionalization of C-H bonds at positions remote to existing functional groups. Here we report enantioselective remote C-H activation using a catalytic amount of a chiral norbornene as a transient mediator, which relays initial ortho-C-H activation to the meta position. This was used in the enantioselective meta-C-H arylation of benzylamines, as well as the arylation and alkylation of homobenzylamines. The enantioselectivities obtained using the chiral transient mediator are comparable across different classes of substrates containing either neutral σ-donor or anionic coordinating groups. This relay strategy could provide an alternative means to remote chiral induction, one of the most challenging problems in asymmetric catalysis 3,4 .

AESOP: An interactive computer program for the design of linear quadratic regulators and Kalman filters

NASA Technical Reports Server (NTRS)

Lehtinen, B.; Geyser, L. C.

1984-01-01

AESOP is a computer program for use in designing feedback controls and state estimators for linear multivariable systems. AESOP is meant to be used in an interactive manner. Each design task that the program performs is assigned a "function" number. The user accesses these functions either (1) by inputting a list of desired function numbers or (2) by inputting a single function number. In the latter case the choice of the function will in general depend on the results obtained by the previously executed function. The most important of the AESOP functions are those that design,linear quadratic regulators and Kalman filters. The user interacts with the program when using these design functions by inputting design weighting parameters and by viewing graphic displays of designed system responses. Supporting functions are provided that obtain system transient and frequency responses, transfer functions, and covariance matrices. The program can also compute open-loop system information such as stability (eigenvalues), eigenvectors, controllability, and observability. The program is written in ANSI-66 FORTRAN for use on an IBM 3033 using TSS 370. Descriptions of all subroutines and results of two test cases are included in the appendixes.

TauG-guidance of transients in expressive musical performance.

PubMed

Schogler, Benjaman; Pepping, Gert-Jan; Lee, David N

2008-08-01

The sounds in expressive musical performance, and the movements that produce them, offer insight into temporal patterns in the brain that generate expression. To gain understanding of these brain patterns, we analyzed two types of transient sounds, and the movements that produced them, during a vocal duet and a bass solo. The transient sounds studied were inter-tone f (0)(t)-glides (the continuous change in fundamental frequency, f (0)(t), when gliding from one tone to the next), and attack intensity-glides (the continuous rise in sound intensity when attacking, or initiating, a tone). The temporal patterns of the inter-tone f (0)(t)-glides and attack intensity-glides, and of the movements producing them, all conformed to the mathematical function, tau (G)(t) (called tauG), predicted by General Tau Theory, and assumed to be generated in the brain. The values of the parameters of the tau (G)(t) function were modulated by the performers when they modulated musical expression. Thus the tau (G)(t) function appears to be a fundamental of brain activity entailed in the generation of expressive temporal patterns of movement and sound.

CFORM- LINEAR CONTROL SYSTEM DESIGN AND ANALYSIS: CLOSED FORM SOLUTION AND TRANSIENT RESPONSE OF THE LINEAR DIFFERENTIAL EQUATION

NASA Technical Reports Server (NTRS)

Jamison, J. W.

1994-01-01

CFORM was developed by the Kennedy Space Center Robotics Lab to assist in linear control system design and analysis using closed form and transient response mechanisms. The program computes the closed form solution and transient response of a linear (constant coefficient) differential equation. CFORM allows a choice of three input functions: the Unit Step (a unit change in displacement); the Ramp function (step velocity); and the Parabolic function (step acceleration). It is only accurate in cases where the differential equation has distinct roots, and does not handle the case for roots at the origin (s=0). Initial conditions must be zero. Differential equations may be input to CFORM in two forms - polynomial and product of factors. In some linear control analyses, it may be more appropriate to use a related program, Linear Control System Design and Analysis (KSC-11376), which uses root locus and frequency response methods. CFORM was written in VAX FORTRAN for a VAX 11/780 under VAX VMS 4.7. It has a central memory requirement of 30K. CFORM was developed in 1987.

Unsteady hovering wake parameters identified from dynamic model tests, part 1

NASA Technical Reports Server (NTRS)

Hohenemser, K. H.; Crews, S. T.

1977-01-01

The development of a 4-bladed model rotor is reported that can be excited with a simple eccentric mechanism in progressing and regressing modes with either harmonic or transient inputs. Parameter identification methods were applied to the problem of extracting parameters for linear perturbation models, including rotor dynamic inflow effects, from the measured blade flapping responses to transient pitch stirring excitations. These perturbation models were then used to predict blade flapping response to other pitch stirring transient inputs, and rotor wake and blade flapping responses to harmonic inputs. The viability and utility of using parameter identification methods for extracting the perturbation models from transients are demonstrated through these combined analytical and experimental studies.

Suppression of thermal transients in advanced LIGO interferometers using CO2 laser preheating

NASA Astrophysics Data System (ADS)

Jaberian Hamedan, V.; Zhao, C.; Ju, L.; Blair, C.; Blair, D. G.

2018-06-01

In high optical power interferometric gravitational wave detectors, such as Advanced LIGO, the thermal effects due to optical absorption in the mirror coatings and the slow thermal response of fused silica substrate cause time dependent changes in the mirror profile. After locking, high optical power builds up in the arm cavities. Absorption induced heating causes optical cavity transverse mode frequencies to drift over a period of hours, relative to the fundamental mode. At high optical power this can cause time dependent transient parametric instability, which can lead to interferometer disfunction. In this paper, we model the use of CO2 laser heating designed to enable the interferometer to be maintained in a thermal condition such that transient changes in the mirrors are greatly reduced. This can minimize transient parametric instability and compensate dark port power fluctuations. Modeling results are presented for both single compensation where a CO2 laser acting on one test mass per cavity, and double compensation using one CO2 laser for each test mass. Using parameters of the LIGO Hanford Observatory X-arm as an example, single compensation allows the maximum mode frequency shift to be limited to 6% of its uncompensated value. However, single compensation causes transient degradation of the contrast defect. Double compensation minimise contrast defect degradation and reduces transients to less than 1% if the CO2 laser spot is positioned within 2 mm of the cavity beam position.

Transient triggering of near and distant earthquakes

USGS Publications Warehouse

Gomberg, J.; Blanpied, M.L.; Beeler, N.M.

1997-01-01

We demonstrate qualitatively that frictional instability theory provides a context for understanding how earthquakes may be triggered by transient loads associated with seismic waves from near and distance earthquakes. We assume that earthquake triggering is a stick-slip process and test two hypotheses about the effect of transients on the timing of instabilities using a simple spring-slider model and a rate- and state-dependent friction constitutive law. A critical triggering threshold is implicit in such a model formulation. Our first hypothesis is that transient loads lead to clock advances; i.e., transients hasten the time of earthquakes that would have happened eventually due to constant background loading alone. Modeling results demonstrate that transient loads do lead to clock advances and that the triggered instabilities may occur after the transient has ceased (i.e., triggering may be delayed). These simple "clock-advance" models predict complex relationships between the triggering delay, the clock advance, and the transient characteristics. The triggering delay and the degree of clock advance both depend nonlinearly on when in the earthquake cycle the transient load is applied. This implies that the stress required to bring about failure does not depend linearly on loading time, even when the fault is loaded at a constant rate. The timing of instability also depends nonlinearly on the transient loading rate, faster rates more rapidly hastening instability. This implies that higher-frequency and/or longer-duration seismic waves should increase the amount of clock advance. These modeling results and simple calculations suggest that near (tens of kilometers) small/moderate earthquakes and remote (thousands of kilometers) earthquakes with magnitudes 2 to 3 units larger may be equally effective at triggering seismicity. Our second hypothesis is that some triggered seismicity represents earthquakes that would not have happened without the transient load (i.e., accumulated strain energy would have been relieved via other mechanisms). We test this using two "new-seismicity" models that (1) are inherently unstable but slide at steady-state conditions under the background load and (2) are conditionally stable such that instability occurs only for sufficiently large perturbations. For the new-seismicity models, very small-amplitude transients trigger instability relative to the clock-advance models. The unstable steady-state models predict that the triggering delay depends inversely and nonlinearly on the transient amplitude (as in the clock-advance models). We were unable to generate delayed triggering with conditionally stable models. For both new-seismicity models, the potential for triggering is independent of when the transient load is applied or, equivalently, of the prestress (unlike in the clock-advance models). In these models, a critical triggering threshold appears to be inversely proportional to frequency. Further advancement of our understanding will require more sophisticated, quantitative models and observations that distinguish between our qualitative, yet distinctly different, model predictions.

Understanding Charge Collection Mechanisms in InGaAs FinFETs Using High-Speed Pulsed-Laser Transient Testing With Tunable Wavelength

NASA Astrophysics Data System (ADS)

Ni, Kai; Sternberg, Andrew L.; Zhang, En Xia; Kozub, John A.; Jiang, Rong; Schrimpf, Ronald D.; Reed, Robert A.; Fleetwood, Daniel M.; Alles, Michael L.; McMorrow, Dale; Lin, Jianqiang; Vardi, Alon; del Alamo, Jesús

2017-08-01

A tunable wavelength laser system and high-resolution transient capture system are introduced to characterize transients in high-mobility MOSFETs. The experimental configuration enables resolution of fast transient signals and new understanding of charge collection mechanisms. The channel layer is critical in the charge collection process for the InGaAs FinFETs examined here. The transient current mainly comes from the channel current, due to shunt effects and parasitic bipolar effects, instead of the junction collection. The charge amplification factor is found to be as high as 14, which makes this technology relatively sensitive to transient radiation. The peak current is inversely proportional to the device gate length. Simulations show that the parasitic bipolar effect is due to source-to-channel barrier lowering caused by hole accumulation in the source and channel. Charge deposited in the channel causes prompt current, while charge deposited below the channel causes delayed and slow current.

Instrumented Taylor anvil-on-rod impact tests for validating applicability of standard strength models to transient deformation states

NASA Astrophysics Data System (ADS)

Eakins, D. E.; Thadhani, N. N.

2006-10-01

Instrumented Taylor anvil-on-rod impact tests have been conducted on oxygen-free electronic copper to validate the accuracy of current strength models for predicting transient states during dynamic deformation events. The experiments coupled the use of high-speed digital photography to record the transient deformation states and laser interferometry to monitor the sample back (free surface) velocity as a measure of the elastic/plastic wave propagation through the sample length. Numerical continuum dynamics simulations of the impact and plastic wave propagation employing the Johnson-Cook [Proceedings of the Seventh International Symposium on Ballistics, 1983, The Netherlands (Am. Def. Prep. Assoc. (ADPA)), pp. 541-547], Zerilli-Armstrong [J. Appl. Phys. C1, 1816 (1987)], and Steinberg-Guinan [J. Appl. Phys. 51, 1498 (1980)] constitutive equations were used to generate transient deformation profiles and the free surface velocity traces. While these simulations showed good correlation with the measured free surface velocity traces and the final deformed sample shape, varying degrees of deviations were observed between the photographed and calculated specimen profiles at intermediate deformation states. The results illustrate the usefulness of the instrumented Taylor anvil-on-rod impact technique for validating constitutive equations that can describe the path-dependent deformation response and can therefore predict the transient and final deformation states.

The PANDA tests for SBWR certification

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

Varadi, G.; Dreier, J.; Bandurski, Th.

1996-03-01

The ALPHA project is centered around the experimental and analytical investigation of the long-term decay heat removal from the containments of the next generation of {open_quotes}passive{close_quotes} ALWRs. The project includes integral system tests in the large-scale (1:25 in volume) PANDA facility as well as several other series of tests and supporting analytical work. The first series of experiments to be conducted in PANDA have become a required experimental element in the certification process for the General Electric Simplified Boiling Water Reactor (SBWR). The PANDA general experimental philosophy, facility design, scaling, and instrumentation are described. Steady-state PCCS condenser performance tests andmore » extensive facility characterization tests were already conducted. The transient system behavior tests are underway; preliminary results from the first transient test M3 are reviewed.« less

An investigation on die crack detection using Temperature Sensitive Parameter for high speed LED mass production

NASA Astrophysics Data System (ADS)

Annaniah, Luruthudass; Devarajan, Mutharasu; San, Teoh Kok

To ensure the highest quality & long-term reliability of LED components it is necessary to examine LED dice that have sustained mechanical damage during the manufacturing process. This paper has demonstrated that detection of die crack in mass manufactured LEDs can be achieved by measuring Temperature Sensitive Parameters (TSPs) during final testing. A newly-designed apparatus and microcontroller was used for this investigation in order to achieve the millisecond switching time needed for detecting thermal transient effects and at the same time meet the expected speed for mass manufacturing. Evaluations conducted at lab scale shows that thermal transient behaviour of cracked die is significantly different than that of an undamaged die. Having an established test limits to differentiate cracked dice, large volume tests in a production environment were used to confirm the effectiveness of this test method. Failure Bin Analysis (FBA) of this high volume experiment confirmed that all the cracked die LEDs were detected and the undamaged LEDs passed this test without over-rejection. The work verifies that tests based on TSP are effective in identifying die cracks and it is believed that the method could be extended to other types of rejects that have thermal transient signatures such as die delamination.

Multivariable Robust Control of a Simulated Hybrid Solid Oxide Fuel Cell Gas Turbine Plant

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

Tsai, Alex; Banta, Larry; Tucker, David

2010-08-01

This work presents a systematic approach to the multivariable robust control of a hybrid fuel cell gas turbine plant. The hybrid configuration under investigation built by the National Energy Technology Laboratory comprises a physical simulation of a 300kW fuel cell coupled to a 120kW auxiliary power unit single spool gas turbine. The public facility provides for the testing and simulation of different fuel cell models that in turn help identify the key difficulties encountered in the transient operation of such systems. An empirical model of the built facility comprising a simulated fuel cell cathode volume and balance of plant componentsmore » is derived via frequency response data. Through the modulation of various airflow bypass valves within the hybrid configuration, Bode plots are used to derive key input/output interactions in transfer function format. A multivariate system is then built from individual transfer functions, creating a matrix that serves as the nominal plant in an H{sub {infinity}} robust control algorithm. The controller’s main objective is to track and maintain hybrid operational constraints in the fuel cell’s cathode airflow, and the turbo machinery states of temperature and speed, under transient disturbances. This algorithm is then tested on a Simulink/MatLab platform for various perturbations of load and fuel cell heat effluence. As a complementary tool to the aforementioned empirical plant, a nonlinear analytical model faithful to the existing process and instrumentation arrangement is evaluated and designed in the Simulink environment. This parallel task intends to serve as a building block to scalable hybrid configurations that might require a more detailed nonlinear representation for a wide variety of controller schemes and hardware implementations.« less

Postnatal glucocorticoid-induced hypomyelination, gliosis, neurologic deficits are dose-dependent, preparation-specific, and reversible

PubMed Central

Zia, Muhammad TK; Vinukonda, Govindaiah; Vose, Linnea; Bhimavarapu, Bala B.R.; Iacobas, Sanda; Pandey, Nishi K.; Beall, Ann Marie; Dohare, Preeti; LaGamma, Edmund F.; Iacobas, Dumitru A.; Ballabh, Praveen

2014-01-01

Postnatal glucocorticoids (GCs) are widely used in the prevention of chronic lung disease in premature infants. Their pharmacologic use is associated with neurodevelopmental delay and cerebral palsy. However, the effect of GC dose and preparation (dexamethasone versus betamethasone) on short and long-term neurological outcomes remains undetermined, and the mechanisms of GC-induced brain injury are unclear. We hypothesized that postnatal GC would induce hypomyelination and motor impairment in a preparation- and dose-specific manner, and that GC receptor (GR) inhibition might restore myelination and neurological function in GC-treated animals. Additionally, GC-induced hypomyelination and neurological deficit might be transient. To test our hypotheses, we treated prematurely delivered rabbit pups with high (0.5 mg/kg/day) or low (0.2 mg/kg/day) doses of dexamethasone or betamethasone. Myelin basic protein (MBP), oligodendrocyte proliferation and maturation, astrocytes, transcriptomic profile, and neurobehavioral functions were evaluated. We found that high-dose GC treatment, but not low-dose, reduced MBP expression and impaired motor function at postnatal day 14. High-dose dexamethasone induced astrogliosis, betamethasone did not. Mifepristone, a GR antagonist, reversed dexamethasone-induced myelination, but not astrogliosis. Both GCs inhibited oligodendrocyte proliferation and maturation. Moreover, high-dose dexamethasone altered genes associated with myelination, cell-cycle, GR, and Mitogen-activated protein kinase. Importantly, GC-induced hypomyelination, gliosis, and motor-deficit, observed at day 14, completely recovered by day 21. Hence, high-dose, but not low-dose, postnatal GC causes reversible reductions in myelination and motor functions. GC treatment induces hypomyelination by GR-dependent genomic mechanisms, but astrogliosis by non-genomic mechanisms. GC-induced motor impairment and neurodevelopmental delay might be transient and recover spontaneously in premature infants. PMID:25263581

Does extracorporeal shock wave lithotripsy cause hearing impairment in children?

PubMed

Tuncer, Murat; Sahin, Cahit; Yazici, Ozgur; Kafkasli, Alper; Turk, Akif; Erdogan, Banu A; Faydaci, Gokhan; Sarica, Kemal

2015-03-01

We evaluated the possible effects of noise created by high energy shock waves on the hearing function of children treated with extracorporeal shock wave lithotripsy. A total of 65 children with normal hearing function were included in the study. Patients were divided into 3 groups, ie those becoming stone-free after 1 session of shock wave lithotripsy (group 1, 22 children), those requiring 3 sessions to achieve stone-free status (group 2, 21) and healthy children/controls (group 3, 22). Extracorporeal shock wave lithotripsy was applied with patients in the supine position with a 90-minute frequency and a total of 2,000 shock waves in each session (Compact Sigma, Dornier MedTech, Wessling, Germany). Second energy level was used with a maximum energy value of 58 joules per session in all patients. Hearing function and possible cochlear impairment were evaluated by transient evoked otoacoustic emissions test at 1.0, 1.4, 2.0, 2.8 and 4.0 kHz frequencies before the procedure, 2 hours later, and 1 month after completion of the first shock wave lithotripsy session in groups 1 and 2. In controls the same evaluation procedures were performed at the beginning of the study and 7 weeks later. Regarding transient evoked otoacoustic emissions data, in groups 1 and 2 there was no significant alteration in values obtained after shock wave lithotripsy compared to values obtained at the beginning of the study, similar to controls. A well planned shock wave lithotripsy procedure is a safe and effective treatment in children with urinary stones and causes no detectable harmful effect on hearing function. Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Coincident steam generator tube rupture and stuck-open safety relief valve carryover tests: MB-2 steam generator transient response test program

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

Garbett, K; Mendler, O J; Gardner, G C

In PWR steam generator tube rupture (SGTR) faults, a direct pathway for the release of radioactive fission products can exist if there is a coincident stuck-open safety relief valve (SORV) or if the safety relief valve is cycled. In addition to the release of fission products from the bulk steam generator water by moisture carryover, there exists the possibility that some primary coolant may be released without having first mixed with the bulk water - a process called primary coolant bypassing. The MB-2 Phase II test program was designed specifically to identify the processes for droplet carryover during SGTR faultsmore » and to provide data of sufficient accuracy for use in developing physical models and computer codes to describe activity release. The test program consisted of sixteen separate tests designed to cover a range of steady-state and transient fault conditions. These included a full SGTR/SORV transient simulation, two SGTR overfill tests, ten steady-state SGTR tests at water levels ranging from very low levels in the bundle up to those when the dryer was flooded, and three moisture carryover tests without SGTR. In these tests the influence of break location and the effect of bypassing the dryer were also studied. In a final test the behavior with respect to aerosol particles in a dry steam generator, appropriate to a severe accident fault, was investigated.« less

An application of polymer-enhanced capillary transient isotachophoresis with an emissive boronic acid functionalized squarylium dye as an on-capillary labeling agent for gram-positive bacteria.

PubMed

Saito, Shingo; Maeda, Takeshi; Nakazumi, Hiroyuki; Colyer, Christa L

2013-01-01

In this paper, the characterization and application of the "PectI" (polymer-enhanced capillary transient isotachophoresis) technique for the separation and detection of same genus, gram-positive bacteria, Bacillus globigii (Bg) and Bacillus subtilis, is demonstrated by employing a boronic acid-functionalized squarylium dye (SQ-BA) as an on-capillary labeling agent, including the quantitative performance and applicability to crude samples. The effect of borate in the separation buffer was also investigated, which revealed that borate strongly affects the separation behavior of bacteria.

Defining and measuring the mean residence time of lateral surface transient storage zones in small streams

Treesearch

T.R. Jackson; R. Haggerty; S.V. Apte; A. Coleman; K.J. Drost

2012-01-01

Surface transient storage (STS) has functional significance in stream ecosystems because it increases solute interaction with sediments. After volume, mean residence time is the most important metric of STS, but it is unclear how this can be measured accurately or related to other timescales and field-measureable parameters. We studied mean residence time of lateral...

Research on radiation detectors, boiling transients, and organic lubricants

NASA Technical Reports Server (NTRS)

1974-01-01

The accomplishments of a space projects research facility are presented. The subjects discussed are: (1) a study of radiation resistant semiconductor devices, (2) synthesis of high temperature organic lubricants, (3) departure from phase equilibrium during boiling transients, (4) effects of neutron irradiation on defect state in tungsten, and (5) determination of photon response function of NE-213 liquid scintillation detectors.

FlashPhotol: Using a Flash Photolysis Apparatus Simulator to Introduce Students to the Kinetics of Transient Species and Fast Reactions

ERIC Educational Resources Information Center

Bigger, Stephen W.

2016-01-01

FlashPhotol is an educational software package that introduces students to the kinetics of transient species and fast reactions. This is achieved by means of a computer-simulated flash photolysis apparatus that comprises all major functional elements and that students can use to perform various experiments. The experimental interface presents a…

Can We Remember Future Actions yet Forget the Last Two Minutes? Study in Transient Global Amnesia

ERIC Educational Resources Information Center

Hainselin, Mathieu; Quinette, Peggy; Desgranges, Beatrice; Martinaud, Olivier; Hannequin, Didier; de La Sayette, Vincent; Viader, Fausto; Eustache, Francis

2011-01-01

Transient global amnesia (TGA) is a clinical syndrome characterized by the abrupt onset of a massive episodic memory deficit that spares other cognitive functions. If the anterograde dimension is known to be impaired in TGA, researchers have yet to investigate prospective memory (PM)--which involves remembering to perform an intended action at…

Materials and processing approaches for foundry-compatible transient electronics.

PubMed

Chang, Jan-Kai; Fang, Hui; Bower, Christopher A; Song, Enming; Yu, Xinge; Rogers, John A

2017-07-11

Foundry-based routes to transient silicon electronic devices have the potential to serve as the manufacturing basis for "green" electronic devices, biodegradable implants, hardware secure data storage systems, and unrecoverable remote devices. This article introduces materials and processing approaches that enable state-of-the-art silicon complementary metal-oxide-semiconductor (CMOS) foundries to be leveraged for high-performance, water-soluble forms of electronics. The key elements are ( i ) collections of biodegradable electronic materials (e.g., silicon, tungsten, silicon nitride, silicon dioxide) and device architectures that are compatible with manufacturing procedures currently used in the integrated circuit industry, ( ii ) release schemes and transfer printing methods for integration of multiple ultrathin components formed in this way onto biodegradable polymer substrates, and ( iii ) planarization and metallization techniques to yield interconnected and fully functional systems. Various CMOS devices and circuit elements created in this fashion and detailed measurements of their electrical characteristics highlight the capabilities. Accelerated dissolution studies in aqueous environments reveal the chemical kinetics associated with the underlying transient behaviors. The results demonstrate the technical feasibility for using foundry-based routes to sophisticated forms of transient electronic devices, with functional capabilities and cost structures that could support diverse applications in the biomedical, military, industrial, and consumer industries.

Materials and processing approaches for foundry-compatible transient electronics

NASA Astrophysics Data System (ADS)

Chang, Jan-Kai; Fang, Hui; Bower, Christopher A.; Song, Enming; Yu, Xinge; Rogers, John A.

2017-07-01

Foundry-based routes to transient silicon electronic devices have the potential to serve as the manufacturing basis for “green” electronic devices, biodegradable implants, hardware secure data storage systems, and unrecoverable remote devices. This article introduces materials and processing approaches that enable state-of-the-art silicon complementary metal-oxide-semiconductor (CMOS) foundries to be leveraged for high-performance, water-soluble forms of electronics. The key elements are (i) collections of biodegradable electronic materials (e.g., silicon, tungsten, silicon nitride, silicon dioxide) and device architectures that are compatible with manufacturing procedures currently used in the integrated circuit industry, (ii) release schemes and transfer printing methods for integration of multiple ultrathin components formed in this way onto biodegradable polymer substrates, and (iii) planarization and metallization techniques to yield interconnected and fully functional systems. Various CMOS devices and circuit elements created in this fashion and detailed measurements of their electrical characteristics highlight the capabilities. Accelerated dissolution studies in aqueous environments reveal the chemical kinetics associated with the underlying transient behaviors. The results demonstrate the technical feasibility for using foundry-based routes to sophisticated forms of transient electronic devices, with functional capabilities and cost structures that could support diverse applications in the biomedical, military, industrial, and consumer industries.

Most-Critical Transient Disturbances in an Incompressible Flat-Plate Boundary Layer

NASA Astrophysics Data System (ADS)

Monschke, Jason; White, Edward

2015-11-01

Transient growth is a linear disturbance growth mechanism that plays a key role in roughness-induced boundary-layer transition. It occurs when superposed stable, non-orthogonal continuous spectrum modes experience algebraic disturbance growth followed by exponential decay. Algebraic disturbance growth can modify the basic state making it susceptible to secondary instabilities rapidly leading to transition. Optimal disturbance theory was developed to model the most-dangerous disturbances. However, evidence suggests roughness-induced transient growth is sub-optimal yet leads to transition earlier than optimal theory suggests. This research computes initial disturbances most unstable to secondary instabilities to further develop the applicability of transient growth theory to surface roughness. The main approach is using nonlinear adjoint optimization with solutions of the parabolized Navier-Stokes and BiGlobal stability equations. Two objective functions were considered: disturbance kinetic energy growth and sinuous instability growth rate. The first objective function was used as validation of the optimization method. Counter-rotating streamwise vortices located low in the boundary layer maximize the sinuous instability growth rate. The authors would like to acknowledge NASA and the AFOSR for funding this work through AFOSR Grant FA9550-09-1-0341.

An RL10A-3-3A rocket engine model using the rocket engine transient simulator (ROCETS) software

NASA Technical Reports Server (NTRS)

Binder, Michael

1993-01-01

Steady-state and transient computer models of the RL10A-3-3A rocket engine have been created using the Rocket Engine Transient Simulation (ROCETS) code. These models were created for several purposes. The RL10 engine is a critical component of past, present, and future space missions; the model will give NASA an in-house capability to simulate the performance of the engine under various operating conditions and mission profiles. The RL10 simulation activity is also an opportunity to further validate the ROCETS program. The ROCETS code is an important tool for modeling rocket engine systems at NASA Lewis. ROCETS provides a modular and general framework for simulating the steady-state and transient behavior of any desired propulsion system. Although the ROCETS code is being used in a number of different analysis and design projects within NASA, it has not been extensively validated for any system using actual test data. The RL10A-3-3A has a ten year history of test and flight applications; it should provide sufficient data to validate the ROCETS program capability. The ROCETS models of the RL10 system were created using design information provided by Pratt & Whitney, the engine manufacturer. These models are in the process of being validated using test-stand and flight data. This paper includes a brief description of the models and comparison of preliminary simulation output against flight and test-stand data.

Time-domain electromagnetic tests in the Wadi Bidah District, Kingdom of Saudi Arabia

USGS Publications Warehouse

Flanigan, Vincent J.; Sadek, Hamdy; Smith, Bruce; Tippens, C.L.

1983-01-01

A time-domain electromagnetic (TDEM) method was tested in two areas of mineralization in Precambrian rocks in the Wadi Bidah district, Kingdom of Saudi Arabia. Transient-decay voltages in profile mode were measured across the Sha'ab at Tare and Rabathan prospects by use of three transmitterreceiver loop configurations. At the Sha'ab at Tare prospect all of the loop configurations indicated the mineralized zone. Analysis of the coincident loop data at Sha'ab at Tare reveals that gossanous and altered rock of i0 ohm-m resistivity extends to a depth of 35 m, where there is an unweathered, dry mineralized zone of about 1 ohm-m resistivity. The model further suggests that the rocks at a depth of 55 m and below the water table are even less resistive (0. 1 ohm-m). The TDEM method successfully discriminated conductors within from those below the weathered zone at the Rabathan prospect. Conductors below the weathered zone are identified by a lack of transient response in the early part of the transient decay curve, followed by an increasing response in the middle to late parts of the transient decay curve. Results of these limited tests suggest the potential value of integrating TDEM with other geophysical tools in the Kingdom. Recommendations are made to expand these tests into a more comprehensive program that will evaluate the TDEM potential in various geologic environments that are host to mineral deposits of diverse origin.

Integration of fracturing dynamics and pressure transient analysis for hydraulic fracture evaluation

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

Arihara, N.; Abbaszadeh, M.; Wright, C.A.

This paper presents pre- and post-fracture pressure transient analysis, combined with net fracture pressure interpretation, for a well in a naturally fractured geothermal reservoir. Integrated analysis was performed to achieve a consistent interpretation of the created fracture geometry, propagation, conductivity, shrinkage, reservoir flow behavior, and formation permeability characteristics. The interpreted data includes two-rate pre-frac injection tests, step-rate injection tests, a series of pressure falloff tests, and the net fracturing pressure from a massive fracture treatment. Pressure transient analyses were performed utilizing advanced well test interpretation techniques and a thermal reservoir simulator with fracture propagation option. Hydraulic fracture propagation analysis wasmore » also performed Milt a generalized 3-D dynamic fracture growth model simulator. Three major conclusions resulted from the combined analysis: (1) that an increasing number of hydraulic fractures were being simultaneously propagated during the fracture treatment. (2) that the reservoir behaved as a composite reservoir Keith the outer region permeability being greater than the permeability of the region immediately surrounding the wellbore, and (3) that the created fractures extended into the outer region during the fracture treatment but retreated to the inner region several days after stimulation had ceased. These conclusions were apparent from independent pressure transient analysis and from independent hydraulic fracture propagation analysis. Integrated interpretation, however, increased the confidence in these conclusions and greatly aided the quantification of the created hydraulic fracture geometry and characterization of the reservoir permeability.« less

Preliminary Analysis of the Transient Reactor Test Facility (TREAT) with PROTEUS

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

Connaway, H. M.; Lee, C. H.

The neutron transport code PROTEUS has been used to perform preliminary simulations of the Transient Reactor Test Facility (TREAT). TREAT is an experimental reactor designed for the testing of nuclear fuels and other materials under transient conditions. It operated from 1959 to 1994, when it was placed on non-operational standby. The restart of TREAT to support the U.S. Department of Energy’s resumption of transient testing is currently underway. Both single assembly and assembly-homogenized full core models have been evaluated. Simulations were performed using a historic set of WIMS-ANL-generated cross-sections as well as a new set of Serpent-generated cross-sections. To supportmore » this work, further analyses were also performed using additional codes in order to investigate particular aspects of TREAT modeling. DIF3D and the Monte-Carlo codes MCNP and Serpent were utilized in these studies. MCNP and Serpent were used to evaluate the effect of geometry homogenization on the simulation results and to support code-to-code comparisons. New meshes for the PROTEUS simulations were created using the CUBIT toolkit, with additional meshes generated via conversion of selected DIF3D models to support code-to-code verifications. All current analyses have focused on code-to-code verifications, with additional verification and validation studies planned. The analysis of TREAT with PROTEUS-SN is an ongoing project. This report documents the studies that have been performed thus far, and highlights key challenges to address in future work.« less

ORNL rod-bundle heat-transfer test data. Volume 2. Thermal-Hydraulic Test Facility experimental data report for test 3. 03. 6AR - transient film boiling in upflow

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

Mullins, C. B.; Felde, D. K.; Sutton, A. G.

1982-04-01

Reduced instrument responses are presented for Thermal-Hydraulic Test Facility (THTF) Test 3.03.6AR. This test was conducted by members of the ORNL Pressurized-Water-Reactor (PWR) Blowdown Heat Transfer (BDHT) Separate-Effects Program on May 21, 1980. Objective was to investigate heat transfer phenomena believed to occur in PWRs during accidents, including small and large break loss-of-coolant accidents. Test 3.03.6AR was conducted to obtain transient film boiling data in rod bundle geometry under reactor accident-type conditions. The primary purpose of this report is to make the reduced instrument responses for THTF Test 3.03.6AR available. Included in the report are uncertainties in the instrument responses,more » calculated mass flows, and calculated rod powers.« less

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

March-Leuba, J.A.

Nuclear plants of the 21st century will employ higher levels of automation and fault tolerance to increase availability, reduce accident risk, and lower operating costs. Key developments in control algorithms, fault diagnostics, fault tolerance, and communication in a distributed system are needed to implement the fully automated plant. Equally challenging will be integrating developments in separate information and control fields into a cohesive system, which collectively achieves the overall goals of improved performance, safety, reliability, maintainability, and cost-effectiveness. Under the Nuclear Energy Research Initiative (NERI), the U. S. Department of Energy is sponsoring a project to address some of themore » technical issues involved in meeting the long-range goal of 21st century reactor control systems. This project, ''A New Paradigm for Automated Development Of Highly Reliable Control Architectures For Future Nuclear Plants,'' involves researchers from Oak Ridge National Laboratory, University of Tennessee, and North Carolina State University. This paper documents a research effort to develop methods for automated generation of control systems that can be traced directly to the design requirements. Our final goal is to allow the designer to specify only high-level requirements and stress factors that the control system must survive (e.g. a list of transients, or a requirement to withstand a single failure.) To this end, the ''control engine'' automatically selects and validates control algorithms and parameters that are optimized to the current state of the plant, and that have been tested under the prescribed stress factors. The control engine then automatically generates the control software from validated algorithms. Examples of stress factors that the control system must ''survive'' are: transient events (e.g., set-point changes, or expected occurrences such a load rejection,) and postulated component failures. These stress factors are specified by the designer and become a database of prescribed transients and component failures. The candidate control systems are tested, and their parameters optimized, for each of these stresses. Examples of high-level requirements are: response time less than xx seconds, or overshoot less than xx% ... etc. In mathematical terms, these types of requirements are defined as ''constraints,'' and there are standard mathematical methods to minimize an objective function subject to constraints. Since, in principle, any control design that satisfies all the above constraints is acceptable, the designer must also select an objective function that describes the ''goodness'' of the control design. Examples of objective functions are: minimize the number or amount of control motions, minimize an energy balance... etc.« less

Ensemble Classifier Strategy Based on Transient Feature Fusion in Electronic Nose

NASA Astrophysics Data System (ADS)

Bagheri, Mohammad Ali; Montazer, Gholam Ali

2011-09-01

In this paper, we test the performance of several ensembles of classifiers and each base learner has been trained on different types of extracted features. Experimental results show the potential benefits introduced by the usage of simple ensemble classification systems for the integration of different types of transient features.

Transport dynamics of a high-power-density matrix-type hydrogen-oxygen fuel cell

NASA Technical Reports Server (NTRS)

Prokopius, P. R.; Hagedorn, N. H.

1974-01-01

Experimental transport dynamics tests were made on a space power fuel cell of current design. Various operating transients were introduced and transport-related response data were recorded with fluidic humidity sensing instruments. Also, sampled data techniques were developed for measuring the cathode-side electrolyte concentration during transient operation.

TREAT Neutronics Analysis and Design Support, Part I: Multi-SERTTA

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

Bess, John D.; Woolstenhulme, Nicolas E.; Hill, Connie M.

2016-08-01

Experiment vehicle design is necessary in preparation for Transient Reactor Test (TREAT) facility restart and the resumption of transient testing to support Accident Tolerant Fuel (ATF) characterization and other future fuels testing requirements. Currently the most mature vehicle design is the Multi-SERTTA (Static Environments Rodlet Transient Test Apparatuses), which can accommodate up to four concurrent rodlet-sized specimens under separate environmental conditions. Robust test vehicle design requires neutronics analyses to support design development, optimization of the power coupling factor (PCF) to efficiently maximize energy generation in the test fuel rodlets, and experiment safety analyses. Calculations were performed to support analysis ofmore » a near-final design of the Multi-SERTTA vehicle, the design process for future TREAT test vehicles, and establish analytical practices for upcoming transient test experiments. Models of the Multi-SERTTA vehicle containing typical PWR-fuel rodlets were prepared and neutronics calculations were performed using MCNP6.1 with ENDF/B-VII.1 nuclear data libraries. Calculation of the PCF for reference conditions of a PWR fuel rodlet in clean water at operational temperature and pressure provided results between 1.10 and 1.74 W/g-MW depending on the location of the four Multi-SERTTA units with the stack. Basic changes to the Multi-SERTTA secondary vessel containment and support have minimal impact on PCF; using materials with less neutron absorption can improve expected PCF values, especially in the primary containment. An optimized balance is needed between structural integrity, experiment safety, and energy deposition in the experiment. Type of medium and environmental conditions within the primary vessel surrounding the fuel rodlet can also have a significant impact on resultant PCF values. The estimated reactivity insertion worth into the TREAT core is impacted more by the primary and secondary Multi-SERTTA vehicle structure with the experiment content and contained environment having a near negligible impact on overall system reactivity. Additional calculations were performed to evaluate the peak-to-average assembly powers throughout the TREAT core, as well as the nuclear heat generation for the various structural components of the Multi-SERTTA assembly. Future efforts include the evaluation of flux collars to shape the PCF for individual Multi-SERTTA units during an experiment such as to achieve uniformity in test unit environmental conditions impacted by the non-uniform axial flux/power profile of TREAT. Upon resumption of transient testing, experimental results from both the Multi-SERTTA and Multi-SERTTA-CAL will be compared against calculational results and methods for further optimization and design strategies.« less

Blade loss transient dynamic analysis of turbomachinery

NASA Technical Reports Server (NTRS)

Stallone, M. J.; Gallardo, V.; Storace, A. F.; Bach, L. J.; Black, G.; Gaffney, E. F.

1982-01-01

This paper reports on work completed to develop an analytical method for predicting the transient non-linear response of a complete aircraft engine system due to the loss of a fan blade, and to validate the analysis by comparing the results against actual blade loss test data. The solution, which is based on the component element method, accounts for rotor-to-casing rubs, high damping and rapid deceleration rates associated with the blade loss event. A comparison of test results and predicted response show good agreement except for an initial overshoot spike not observed in test. The method is effective for analysis of large systems.

Comparative multivariate analyses of transient otoacoustic emissions and distorsion products in normal and impaired hearing.

PubMed

Stamate, Mirela Cristina; Todor, Nicolae; Cosgarea, Marcel

2015-01-01

The clinical utility of otoacoustic emissions as a noninvasive objective test of cochlear function has been long studied. Both transient otoacoustic emissions and distorsion products can be used to identify hearing loss, but to what extent they can be used as predictors for hearing loss is still debated. Most studies agree that multivariate analyses have better test performances than univariate analyses. The aim of the study was to determine transient otoacoustic emissions and distorsion products performance in identifying normal and impaired hearing loss, using the pure tone audiogram as a gold standard procedure and different multivariate statistical approaches. The study included 105 adult subjects with normal hearing and hearing loss who underwent the same test battery: pure-tone audiometry, tympanometry, otoacoustic emission tests. We chose to use the logistic regression as a multivariate statistical technique. Three logistic regression models were developed to characterize the relations between different risk factors (age, sex, tinnitus, demographic features, cochlear status defined by otoacoustic emissions) and hearing status defined by pure-tone audiometry. The multivariate analyses allow the calculation of the logistic score, which is a combination of the inputs, weighted by coefficients, calculated within the analyses. The accuracy of each model was assessed using receiver operating characteristics curve analysis. We used the logistic score to generate receivers operating curves and to estimate the areas under the curves in order to compare different multivariate analyses. We compared the performance of each otoacoustic emission (transient, distorsion product) using three different multivariate analyses for each ear, when multi-frequency gold standards were used. We demonstrated that all multivariate analyses provided high values of the area under the curve proving the performance of the otoacoustic emissions. Each otoacoustic emission test presented high values of area under the curve, suggesting that implementing a multivariate approach to evaluate the performances of each otoacoustic emission test would serve to increase the accuracy in identifying the normal and impaired ears. We encountered the highest area under the curve value for the combined multivariate analysis suggesting that both otoacoustic emission tests should be used in assessing hearing status. Our multivariate analyses revealed that age is a constant predictor factor of the auditory status for both ears, but the presence of tinnitus was the most important predictor for the hearing level, only for the left ear. Age presented similar coefficients, but tinnitus coefficients, by their high value, produced the highest variations of the logistic scores, only for the left ear group, thus increasing the risk of hearing loss. We did not find gender differences between ears for any otoacoustic emission tests, but studies still debate this question as the results are contradictory. Neither gender, nor environment origin had any predictive value for the hearing status, according to the results of our study. Like any other audiological test, using otoacoustic emissions to identify hearing loss is not without error. Even when applying multivariate analysis, perfect test performance is never achieved. Although most studies demonstrated the benefit of using the multivariate analysis, it has not been incorporated into clinical decisions maybe because of the idiosyncratic nature of multivariate solutions or because of the lack of the validation studies.

Comparative multivariate analyses of transient otoacoustic emissions and distorsion products in normal and impaired hearing

PubMed Central

STAMATE, MIRELA CRISTINA; TODOR, NICOLAE; COSGAREA, MARCEL

2015-01-01

Background and aim The clinical utility of otoacoustic emissions as a noninvasive objective test of cochlear function has been long studied. Both transient otoacoustic emissions and distorsion products can be used to identify hearing loss, but to what extent they can be used as predictors for hearing loss is still debated. Most studies agree that multivariate analyses have better test performances than univariate analyses. The aim of the study was to determine transient otoacoustic emissions and distorsion products performance in identifying normal and impaired hearing loss, using the pure tone audiogram as a gold standard procedure and different multivariate statistical approaches. Methods The study included 105 adult subjects with normal hearing and hearing loss who underwent the same test battery: pure-tone audiometry, tympanometry, otoacoustic emission tests. We chose to use the logistic regression as a multivariate statistical technique. Three logistic regression models were developed to characterize the relations between different risk factors (age, sex, tinnitus, demographic features, cochlear status defined by otoacoustic emissions) and hearing status defined by pure-tone audiometry. The multivariate analyses allow the calculation of the logistic score, which is a combination of the inputs, weighted by coefficients, calculated within the analyses. The accuracy of each model was assessed using receiver operating characteristics curve analysis. We used the logistic score to generate receivers operating curves and to estimate the areas under the curves in order to compare different multivariate analyses. Results We compared the performance of each otoacoustic emission (transient, distorsion product) using three different multivariate analyses for each ear, when multi-frequency gold standards were used. We demonstrated that all multivariate analyses provided high values of the area under the curve proving the performance of the otoacoustic emissions. Each otoacoustic emission test presented high values of area under the curve, suggesting that implementing a multivariate approach to evaluate the performances of each otoacoustic emission test would serve to increase the accuracy in identifying the normal and impaired ears. We encountered the highest area under the curve value for the combined multivariate analysis suggesting that both otoacoustic emission tests should be used in assessing hearing status. Our multivariate analyses revealed that age is a constant predictor factor of the auditory status for both ears, but the presence of tinnitus was the most important predictor for the hearing level, only for the left ear. Age presented similar coefficients, but tinnitus coefficients, by their high value, produced the highest variations of the logistic scores, only for the left ear group, thus increasing the risk of hearing loss. We did not find gender differences between ears for any otoacoustic emission tests, but studies still debate this question as the results are contradictory. Neither gender, nor environment origin had any predictive value for the hearing status, according to the results of our study. Conclusion Like any other audiological test, using otoacoustic emissions to identify hearing loss is not without error. Even when applying multivariate analysis, perfect test performance is never achieved. Although most studies demonstrated the benefit of using the multivariate analysis, it has not been incorporated into clinical decisions maybe because of the idiosyncratic nature of multivariate solutions or because of the lack of the validation studies. PMID:26733749

Development and performance evaluation of an MR squeeze-mode damper

NASA Astrophysics Data System (ADS)

Sapiński, Bogdan; Gołdasz, Janusz

2015-11-01

In this paper the authors present results of a magnetorheological (MR) damper prototype development and performance evaluation study. The damper is a device functioning in the so-called squeeze-mode of MR fluid flow regime of operation. By principle, in a squeeze-mode damper the control (working) gap height varies according to the prescribed displacement or force input profile. Such hardware has been claimed to be well suited to small-amplitude vibration damping applications. However, it is still in its infancy. Its potential seems appealing yet unclear. Accordingly, the authors reveal performance figures of the damper complemented by numerical finite-element simulations of the electro-magnetic circuit of the device. The numerical results are presented in the form of maps of averaged magnetic flux density versus coil current and gap height as well as magnetic flux, inductance, and cogging force calculations, respectively. The simulated data are followed by experimental evaluation of the damper performance incorporating plots of force versus piston displacement (velocity) across a prescribed range of excitation inputs. Moreover, some insight into transient (unsteady) characteristics of the device is provided through testing results involving transient currents.

Effects of intracellular injection of calcium buffers on light adaptation in Limulus ventral photoreceptors

PubMed Central

1975-01-01

The calcium sequestering agent, EGTA, was injected into Limulus ventral photoreceptors. Before injection, the inward membrane current induced by a long stimulus had a large initial transient which declined to a smaller plateau. Iontophoretic injection of EGTA tended to prevent the decline from transient to plateau. Before injection the plateau response was a nonlinear function of light intensity. After EGTA injection the response-intensity curves tended to become linear. Before injection, bright lights lowered the sensitivity as determined with subsequent test flashes. EGTA injection decreased the light-induced changes in sensitivity. Ca-EGTA buffers having different levels of free calcium were pressure-injected into ventral photoreceptors; the higher the level of free calcium, the lower the sensitivity measured after injection. The effects of inotophoretic injection of EGTA were not mimicked by injection or similar amounts of sulfate and the effects of pressure injection of EGTA buffer solutions were not mimicked by injection of similar volumes of pH buffer or mannitol. The data are consistent with the hypothesis that light adaptation is mediated by a rise of the intracellular free calcium concentration. PMID:810540

Impulsive artistic creativity as a presentation of transient cognitive alterations.

PubMed

Finkelstein, Y; Vardi, J; Hod, I

1991-01-01

A 27-year-old right-handed male mosaic artisan who had not shown any interest in drawing or artistic activity was admitted to the Department of Neurology for attacks of bizarre behavior and convulsive disorder. The patient reported feeling "waves" engulfing him during the attacks, leaving him floating helplessly. During some attacks, the patient impulsively initiated drawing activity. Interictal sleep-deprivation EEG showed a left frontotemporal focus of paroxysmal discharge. Brain tomography with SPECT showed low 99Tc-HMPAO uptake in the left frontoparietal region. Psychodiagnostic tests gave evidence of dysfunction of the left frontal region, with preference of the right hemisphere. It is suggested that the attacks of altered cognitive state were, in this case, provoked by spreading depression of the left hemisphere, while the integrative functions of the right hemisphere remained intact. Thus, the impulsive artistic creativity during the attacks may represent a "release phenomenon" of the complex visuospatial skills of the right (subdominant) hemisphere. This symptomatology of transient cognitive alterations is unique and, to the best of our knowledge, has not been previously reported.

RNase P cleaves transient structures in some riboswitches.

PubMed

Altman, Sidney; Wesolowski, Donna; Guerrier-Takada, Cecilia; Li, Yong

2005-08-09

RNase P from Escherichia coli cleaves the coenzyme B12 riboswitch from E. coli and a similar one from Bacillus subtilis. The cleavage sites do not occur in any recognizable structure, as judged from theoretical schemes that have been drawn for these 5' UTRs. However, it is possible to draw a scheme that is a good representation of the E. coli cleavage site for RNase P and for the cleavage site in B. subtilis. These data indicate that transient structures are important in RNase P cleavage and in riboswitch function. Coenzyme B12 has a small inhibitory effect on E. coli RNase P cleavage of the E. coli riboswitch. Both E. coli RNase P and a partially purified RNase P from Aspergillus nidulans mycelia succeeded in cleaving a putative arginine riboswitch from A. nidulans. The cleavage site may be a representative of another model substrate for eukaryotic RNase P. This 5' UTR controls splicing of the arginase mRNA in A. nidulans. Four other riboswitches in E. coli were not cleaved by RNase P under the conditions tested.

RNase P cleaves transient structures in some riboswitches

PubMed Central

Altman, Sidney; Wesolowski, Donna; Guerrier-Takada, Cecilia; Li, Yong

2005-01-01

RNase P from Escherichia coli cleaves the coenzyme B12 riboswitch from E. coli and a similar one from Bacillus subtilis. The cleavage sites do not occur in any recognizable structure, as judged from theoretical schemes that have been drawn for these 5′ UTRs. However, it is possible to draw a scheme that is a good representation of the E. coli cleavage site for RNase P and for the cleavage site in B. subtilis. These data indicate that transient structures are important in RNase P cleavage and in riboswitch function. Coenzyme B12 has a small inhibitory effect on E. coli RNase P cleavage of the E. coli riboswitch. Both E. coli RNase P and a partially purified RNase P from Aspergillus nidulans mycelia succeeded in cleaving a putative arginine riboswitch from A. nidulans. The cleavage site may be a representative of another model substrate for eukaryotic RNase P. This 5′ UTR controls splicing of the arginase mRNA in A. nidulans. Four other riboswitches in E. coli were not cleaved by RNase P under the conditions tested. PMID:16061811

Transient Expression of Lumbrokinase (PI239) in Tobacco (Nicotiana tabacum) Using a Geminivirus-Based Single Replicon System Dissolves Fibrin and Blood Clots.

PubMed

Dickey, Alexia; Wang, Nan; Cooper, Edwin; Tull, Lauren; Breedlove, Drew; Mason, Hugh; Liu, Dehu; Wang, Kevin Yueju

2017-01-01

Lumbrokinases, a group of fibrinolytic enzymes extracted from earthworm, have been widely used to prevent and treat various cardiovascular diseases. They specifically target fibrin to effectively degrade thrombi without major side effects. Plant expression systems are becoming potential alternative expression platforms for producing pharmaceutical proteins. In this work, a lumbrokinase (PI239) was produced from a plant system. Both wild-type (WT) and plant codon-optimized (OP) PI239 gene sequences were synthesized and cloned into a geminivirus-based single-vector DNA replicon system. Both vectors were independently expressed in tobacco (Nicotiana tabacum) leaves transiently by agroinfiltration. Overexpressed PI239 resulted in sudden tissue necrosis 3 days after infiltration. Remaining proteins were purified through His-tag affinity chromatography and analyzed with SDS-PAGE and Western blot methods. Purified PI239 successfully degraded artificial fibrin with relative activity of 13,400 U/mg when compared with commercial lumbrokinase product. In vitro tests demonstrated that plant-derived PI239 dissolved human blood clots and that the plant expression system is capable of producing functional PI239.

Exploiting three kinds of interface propensities to identify protein binding sites.

PubMed

Liu, Bin; Wang, Xiaolong; Lin, Lei; Dong, Qiwen; Wang, Xuan

2009-08-01

Predicting the binding sites between two interacting proteins provides important clues to the function of a protein. In this study, we present a building block of proteins called order profiles to use the evolutionary information of the protein sequence frequency profiles and apply this building block to produce a class of propensities called order profile interface propensities. For comparisons, we revisit the usage of residue interface propensities and binary profile interface propensities for protein binding site prediction. Each kind of propensities combined with sequence profiles and accessible surface areas are inputted into SVM. When tested on four types of complexes (hetero-permanent complexes, hetero-transient complexes, homo-permanent complexes and homo-transient complexes), experimental results show that the order profile interface propensities are better than residue interface propensities and binary profile interface propensities. Therefore, order profile is a suitable profile-level building block of the protein sequences and can be widely used in many tasks of computational biology, such as the sequence alignment, the prediction of domain boundary, the designation of knowledge-based potentials and the protein remote homology detection.

Suppression of transient receptor potential melastatin 4 expression promotes conversion of endothelial cells into fibroblasts via transforming growth factor/activin receptor-like kinase 5 pathway.

PubMed

Echeverría, Cesar; Montorfano, Ignacio; Cabello-Verrugio, Claudio; Armisén, Ricardo; Varela, Diego; Simon, Felipe

2015-05-01

To study whether transient receptor potential melastatin 4 (TRPM4) participates in endothelial fibrosis and to investigate the underlying mechanism. Primary human endothelial cells were used and pharmacological and short interfering RNA-based approaches were used to test the transforming growth factor beta (TGF-β)/activin receptor-like kinase 5 (ALK5) pathway participation and contribution of TRPM7 ion channel. Suppression of TRPM4 expression leads to decreased endothelial protein expression and increased expression of fibrotic and extracellular matrix markers. Furthermore, TRPM4 downregulation increases intracellular Ca levels as a potential condition for fibrosis. The underlying mechanism of endothelial fibrosis shows that inhibition of TRPM4 expression induces TGF-β1 and TGF-β2 expression, which act through their receptor, ALK5, and the nuclear translocation of the profibrotic transcription factor smad4. TRPM4 acts to maintain endothelial features and its loss promotes fibrotic conversion via TGF-β production. The regulation of TRPM4 levels could be a target for preserving endothelial function during inflammatory diseases.

Measurements of microhardness during transient horizontal directional solidification of Al-Rich Al-Cu alloys: Effect of thermal parameters, primary dendrite arm spacing and Al2Cu intermetallic phase

NASA Astrophysics Data System (ADS)

Barros, André Santos; Magno, Igor Alexsander; Souza, Fabrício Andrade; Mota, Carlos Alberto; Moreira, Antonio Luciano; Silva, Maria Adrina; Rocha, Otávio Lima

2015-05-01

In this work, the effect of the growth rate (VL) and cooling rate (TR), primary dendritic arm spacing (λ1) and Al2Cu intermetallic phase on the microhardness was investigated during transient horizontal directional solidification of Al-3wt%Cu and Al-8wt%Cu alloys. Microstructural characterization of the investigated alloys was performed using traditional techniques of metallography, optical and SEM microscopy and X-Ray diffraction. The microhardness evolution as a function of the thermal and microstructural parameters (VL, TR, and λ1) was evaluated using power and Hall-Petch type experimental laws, which were compared with other laws in the literature. In order to examine the effect of the Al2Cu intermetallic phase, microhardness measurements were performed in interdendritic regions. Finally, a comparative analysis was performed between the experimental data of this work and theoretical models from the literature that have been proposed to predict primary dendrite arm spacing, which have been tested in numerous works considering upward directional solidification.

Nonviral RNA transfection to transiently modify T cells with chimeric antigen receptors for adoptive therapy.

PubMed

Riet, Tobias; Holzinger, Astrid; Dörrie, Jan; Schaft, Niels; Schuler, Gerold; Abken, Hinrich

2013-01-01

Redirecting T cells with a chimeric antigen receptor (CAR) of predefined specificity showed remarkable efficacy in the adoptive therapy trials of malignant diseases. The CAR consists of a single chain fragment of variable region (scFv) antibody targeting domain covalently linked to the CD3ζ signalling domain of the T cell receptor complex to mediate T cell activation upon antigen engagement. By using an antibody-derived targeting domain a CAR can potentially redirect T cells towards any target expressed on the cell surface as long as a binding domain is available. Antibody-mediated targeting moreover circumvents MHC restriction of the targeted antigen, thereby broadening the potential of applicability of adoptive T cell therapy. While T cells were so far genetically modified by viral transduction, transient modification with a CAR by RNA transfection gained increasing interest during the last years. This chapter focuses on methods to modify human T cells from peripheral blood with a CAR by electroporation of in vitro transcribed RNA and to test modified T cells for function for use in adoptive immunotherapy.

Protective effect of embelin from Embelia ribes Burm. against transient global ischemia-induced brain damage in rats.

PubMed

Thippeswamy, B S; Nagakannan, P; Shivasharan, B D; Mahendran, S; Veerapur, V P; Badami, S

2011-11-01

Embelia ribes is being used in Indian traditional herbal medicine for the treatment of mental disorders and as brain tonic. The present study was designed to investigate the protective effects of embelin from E. ribes on global ischemia/reperfusion-induced brain injury in rats. Transient global ischemia was induced by occluding bilateral common carotid arteries for 30 min followed by 24-h reperfusion. Neurological functions were measured using sensorimotor tests. Ischemia/reperfusion-induced neuronal injury was assessed by cerebral infarct area, biochemical and histopathological examination. Pretreatment of embelin (25 and 50 mg/kg, p.o.) significantly increased locomotor activity and hanging latency time and decreased beam walking latency when compared with ischemic control. The treatment also reduced significantly the lipid peroxidation and increased the total thiol content and glutathione-S-transferase activity in brain homogenates. The decreased cerebral infarction area in embelin-treated groups and histopathological observations confirmed the above findings. These observations suggested that embelin is a neuroprotective agent and may prove to be useful adjunct in the treatment of stroke.

A novel plant protection strategy for transient reactors

NASA Astrophysics Data System (ADS)

Bhattacharyya, Samit K.; Lipinski, Walter C.; Hanan, Nelson A.

A novel plant protection system designed for use in the TREAT Upgrade (TU) reactor is described. The TU reactor is designed for controlled transient operation in the testing of reactor fuel behavior under simulated reactor accident conditions. Safe operation of the reactor is of paramount importance and the Plant Protection System (PPS) had to be designed to exacting requirements. Researchers believe that the strategy developed for the TU has potential application to the multimegawatt space reactors and represents the state of the art in terrestrial transient reactor protection systems.