The Effect of Brain Based Instruction on Student Achievement in Algebra I

ERIC Educational Resources Information Center

Vass, Melissa G.

2010-01-01

This quantitative quasi-experimental study examined the effect of brain-based instruction compared to teacher-centered instruction on student achievement in algebra I. A pre-test and post-test were given to a control group of 30 and experimental group of 42 before and after a unit if study in algebra I, which was taught using the two instructional…

The effects of light curing units and environmental temperatures on C 000000000000 000000000000 000000000000 111111111111 000000000000 111111111111 000000000000 000000000000 000000000000 C conversion of commercial and experimental bonding agents.

PubMed

Jafarzadeh-Kashi, Tahereh Sadat; Erfan, Mohmmad; Kalbasi, Salmeh; Ghadiri, Malihe; Rakhshan, Vahid

2014-10-01

Polymerization of bonding agents (BA) is a critical factor in determining the success of bonded restorations. We aimed to assess the effects of two light curing units and two temperatures on the extent of polymerization (EP) of a commercial BA and an experimental BA. Forty BA specimens were randomly divided into 8 subgroups of n = 5 to compare the polymerization of two BAs (experimental/Scotchbond) based on the variables: temperature (23/37 °C) and light-curing unit (quartz-tungsten-halogen/light-emitting diode). The EP (%) was measured using differential scanning calorimetry, and analyzed using the t-test, two- and three-way analyses of variance (ANOVA), and the Bonferroni test (α = 0.05). There were significant differences between the EP results between the two BAs (P = 0.012) and due to the different temperatures (P = 0.001), but not between the different light-curing units (P = 0.548). The interaction between BA and temperature was significant (P < 0.001). The other interactions were nonsignificant. The two light-curing units had similar effects on the EP. The EP values were better when curing was performed at human body temperature.

The effect of A teacher questioning strategy training program on teaching behavior, student achievement, and retention

NASA Astrophysics Data System (ADS)

Otto, Paul B.; Schuck, Robert F.

The use of questions in the classroom has been employed throughout the recorded history of teaching. One still hears the term Socratic method during discussions of questioning procedures. The use of teacher questions is presently viewed as a viable procedure for effective instruction. This study was conducted to investigate the feasibility of training teachers in the use of a questioning technique and the resultant effect upon student learning. The Post-Test Only Control Group Design was used in randomly assigning teachers and students to experimental and control groups. A group of teachers was trained in the use of a specific questioning technique. Follow-up periodic observations were made of questioning technique behavior while teaching science units to groups of students. Post-unit achievement tests were administered to the student groups to obtain evidence of a relationship between the implementation of specific types of teacher questions and student achievement and retention. Analysis of observation data indicated a higher use of managerial and rhetorical questions by the control group than the experimental group. The experimental group employed a greater number of recall and data gathering questions as well as higher order data processing and data verification type questions. The student posttest achievement scores for both units of instruction were greater for the experimental groups than for the control groups. The retention scores for both units were Beater for the experimental groups than for the control groups.

Improved perceptual-motor performance measurement system

NASA Technical Reports Server (NTRS)

Parker, J. F., Jr.; Reilly, R. E.

1969-01-01

Battery of tests determines the primary dimensions of perceptual-motor performance. Eighteen basic measures range from simple tests to sophisticated electronic devices. Improved system has one unit for the subject containing test display and response elements, and one for the experimenter where test setups, programming, and scoring are accomplished.

Statistical Power in Experimental Audit Studies: Cautions and Calculations for Matched Tests With Nominal Outcomes

ERIC Educational Resources Information Center

Vuolo, Mike; Uggen, Christopher; Lageson, Sarah

2016-01-01

Given their capacity to identify causal relationships, experimental audit studies have grown increasingly popular in the social sciences. Typically, investigators send fictitious auditors who differ by a key factor (e.g., race) to particular experimental units (e.g., employers) and then compare treatment and control groups on a dichotomous outcome…

Development of the CCP-200 mathematical model for Syzran CHPP using the Thermolib software package

NASA Astrophysics Data System (ADS)

Usov, S. V.; Kudinov, A. A.

2016-04-01

Simplified cycle diagram of the CCP-200 power generating unit of Syzran CHPP containing two gas turbines PG6111FA with generators, two steam recovery boilers KUP-110/15-8.0/0.7-540/200, and one steam turbine Siemens SST-600 (one-cylinder with two variable heat extraction units of 60/75 MW in heatextraction and condensing modes, accordingly) with S-GEN5-100 generators was presented. Results of experimental guarantee tests of the CCP-200 steam-gas unit are given. Brief description of the Thermolib application for the MatLab Simulink software package is given. Basic equations used in Thermolib for modeling thermo-technical processes are given. Mathematical models of gas-turbine plant, heat-recovery steam generator, steam turbine and integrated plant for power generating unit CCP-200 of Syzran CHPP were developed with the help of MatLab Simulink and Thermolib. The simulation technique at different ambient temperature values was used in order to get characteristics of the developed mathematical model. Graphic comparison of some characteristics of the CCP-200 simulation model (gas temperature behind gas turbine, gas turbine and combined cycle plant capacity, high and low pressure steam consumption and feed water consumption for high and low pressure economizers) with actual characteristics of the steam-gas unit received at experimental (field) guarantee tests at different ambient temperature are shown. It is shown that the chosen degrees of complexity, characteristics of the CCP-200 simulation model, developed by Thermolib, adequately correspond to the actual characteristics of the steam-gas unit received at experimental (field) guarantee tests; this allows considering the developed mathematical model as adequate and acceptable it for further work.

Experimental study of main rotor/tail rotor/airframe interactions in hover. Volume 1: Text and figures

NASA Technical Reports Server (NTRS)

Balch, D. T.; Saccullo, A.; Sheehy, T. W.

1983-01-01

To assist in identifying and quantifying the relevant parameters associated with the complex topic of main rotor/fuselage/tail rotor interference, a model scale hover test was conducted in the Model Rotor Hover Facility. The test was conducted using the basic model test rig, fuselage skins to represent a UH-60A BLACK HAWK helicopter, 4 sets of rotor blades of varying geometry (i.e., twist, airfoils and solidity) and a model tail rotor that could be relocated to give changes in rotor clearance (axially, laterally, and vertically), can't angle and operating model (pusher or tractor). The description of the models and the tests, data analysis and summary (including plots) are included. The customary system of units gas used for principal measurements and calculations. Expressions in both SI units and customary units are used with the SI units stated first and the customary units afterwords, in parenthesis.

Development and Field Test of the Trial Battery for Project A. Improving the Selection, Classification and Utilization of Army Enlisted Personnel. Project A: Improving the Selection, Classification and Utilization of Army Enlisted Personnel. ARI Technical Report 739.

ERIC Educational Resources Information Center

Peterson, Norman G., Ed.

As part of the United States Army's Project A, research has been conducted to develop and field test a battery of experimental tests to complement the Armed Services Vocational Aptitude Battery in predicting soldiers' job performance. Project A is the United States Army's large-scale manpower effort to improve selection, classification, and…

Compilation of Steady State Automotive Engine Test Data

DOT National Transportation Integrated Search

1978-09-01

Experimental data were obtained in dynamometer tests of automotive engines used in the United States. The objective of this program is to obtain engine performance data for determining fuel consumption and emissions (carbon monoxide, hydrocarbons, an...

Experimental study of air delivery into water-conveyance system of the radial-axial turbine

NASA Astrophysics Data System (ADS)

Maslennikova, Alexandra; Platonov, Dmitry; Minakov, Andrey; Dekterev, Dmitry

2017-10-01

The paper presents an experimental study of oscillatory response in the Francis turbine of hydraulic unit. The experiment was performed on large-scale hydrodynamic test-bench with impeller diameter of 0.3 m. The effect of air injection on the intensity of pressure pulsations was studied at the maximum pressure pulsations in the hydraulic unit. It was revealed that air delivery into the water-conveyance system of the turbine results in almost two-fold reduction of pressure pulsations.

Multichannel electrochemical microbial detection unit

NASA Technical Reports Server (NTRS)

Wilkins, J. R.; Young, R. N.; Boykin, E. H.

1978-01-01

The paper describes the design and capabilities of a compact multichannel electrochemical unit devised to detect and automatically indicate detection time length of bacteria. By connecting this unit to a strip-chart recorder, a permanent record is obtained of the end points and growth curves for each of eight channels. The experimental setup utilizing the multichannel unit consists of a test tube (25 by 150 mm) containing a combination redox electrode plus 18 ml of lauryl tryptose broth and positioned in a 35-C water bath. Leads from the electrodes are connected to the multichannel unit, which in turn is connected to a strip-chart recorder. After addition of 2.0 ml of inoculum to the test tubes, depression of the push-button starter activates the electronics, timer, and indicator light for each channel. The multichannel unit is employed to test tenfold dilutions of various members of the Enterobacteriaceae group, and a typical dose-response curve is presented.

27 CFR 1.61 - Use of wine.

Code of Federal Regulations, 2013 CFR

2013-04-01

... for experimental or research purposes by any scientific university, college of learning, or institution of scientific research; or (c) Free of tax for use by the United States or any agency thereof, and for use for analysis, testing, research, or experimentation by the governments of the several States...

27 CFR 1.61 - Use of wine.

Code of Federal Regulations, 2014 CFR

2014-04-01

... for experimental or research purposes by any scientific university, college of learning, or institution of scientific research; or (c) Free of tax for use by the United States or any agency thereof, and for use for analysis, testing, research, or experimentation by the governments of the several States...

27 CFR 1.61 - Use of wine.

Code of Federal Regulations, 2012 CFR

2012-04-01

... for experimental or research purposes by any scientific university, college of learning, or institution of scientific research; or (c) Free of tax for use by the United States or any agency thereof, and for use for analysis, testing, research, or experimentation by the governments of the several States...

27 CFR 1.61 - Use of wine.

Code of Federal Regulations, 2011 CFR

2011-04-01

... for experimental or research purposes by any scientific university, college of learning, or institution of scientific research; or (c) Free of tax for use by the United States or any agency thereof, and for use for analysis, testing, research, or experimentation by the governments of the several States...

27 CFR 1.61 - Use of wine.

Code of Federal Regulations, 2010 CFR

2010-04-01

... for experimental or research purposes by any scientific university, college of learning, or institution of scientific research; or (c) Free of tax for use by the United States or any agency thereof, and for use for analysis, testing, research, or experimentation by the governments of the several States...

Using the Teach-Back Method in Patient Education to Improve Patient Satisfaction.

PubMed

Centrella-Nigro, Andrea M; Alexander, Catherine

2017-01-01

This quasi-experimental research study used two similar nursing units to test the effects of teach back on Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) scores. A pretest-posttest design tested 24 nurses' knowledge, attitudes, and beliefs about teach back. Education specialists provided a 1-hour teaching session on teach back to all nurses in the intervention unit. A significant improvement in knowledge scores in the pretest-posttest was found using paired t tests (p = .002). Qualitative analysis of nurses' comments demonstrated strong support for teach back in the post-test. The HCAHPS scores were not significantly improved in the intervention unit when compared with the control unit. More research needs to be conducted to determine the effectiveness of teach back on HCAHPS scores. J Contin Educ Nurs. 2017;48(1):47-52. Copyright 2017, SLACK Incorporated.

Age related neuromuscular changes in sEMG of m. Tibialis Anterior using higher order statistics (Gaussianity & linearity test).

PubMed

Siddiqi, Ariba; Arjunan, Sridhar P; Kumar, Dinesh K

2016-08-01

Age-associated changes in the surface electromyogram (sEMG) of Tibialis Anterior (TA) muscle can be attributable to neuromuscular alterations that precede strength loss. We have used our sEMG model of the Tibialis Anterior to interpret the age-related changes and compared with the experimental sEMG. Eighteen young (20-30 years) and 18 older (60-85 years) performed isometric dorsiflexion at 6 different percentage levels of maximum voluntary contractions (MVC), and their sEMG from the TA muscle was recorded. Six different age-related changes in the neuromuscular system were simulated using the sEMG model at the same MVCs as the experiment. The maximal power of the spectrum, Gaussianity and Linearity Test Statistics were computed from the simulated and experimental sEMG. A correlation analysis at α=0.05 was performed between the simulated and experimental age-related change in the sEMG features. The results show the loss in motor units was distinguished by the Gaussianity and Linearity test statistics; while the maximal power of the PSD distinguished between the muscular factors. The simulated condition of 40% loss of motor units with halved the number of fast fibers best correlated with the age-related change observed in the experimental sEMG higher order statistical features. The simulated aging condition found by this study corresponds with the moderate motor unit remodelling and negligible strength loss reported in literature for the cohorts aged 60-70 years.

Joint Services Electronics Program.

DTIC Science & Technology

1983-04-01

shape of the photon-assisted tunneling features and of their dependence on laser power. The cleanest test of the theory was made at 4.2 K, above T...Properties of Small-area Tunnel Junctions by research unit 2; Nonequilibrium Switching Phenomena on Picosecond Time Scales by research unit 2; Liquid...ocean, with the lower ends grounded or joined by a third conductor in a tunnel through the mountain has been suc-Tested. A theoretical and experimental

A Quasi-Experimental Study of Two Selected Units of the Industrial Arts Curriculum Project Materials to Determine the Measurable Additive Effects of a Unit on Design in Manfacturing Technology upon a Similar Unit on Design in Construction Technology.

ERIC Educational Resources Information Center

Kuwik, Paul David

The purpose of the study was to determine whether exposing junior high school students to a unit on design in construction technology and to a unit on design in manufacturing technology significantly affects their achievement on a test measuring "Technological Principles of Design" when compared to a group of junior high school students exposed…

Multiple ways to the prior occurrence of an event: an electrophysiological dissociation of experimental and conceptually driven familiarity in recognition memory.

PubMed

Wiegand, Iris; Bader, Regine; Mecklinger, Axel

2010-11-11

Recent research has shown that familiarity contributes to associative memory when the to-be-associated stimuli are unitized during encoding. However, the specific processes underlying familiarity-based recognition of unitized representations are still indefinite. In this study, we present electrophysiologically dissociable early old/new effects, presumably related to two different kinds of familiarity inherent in associative recognition tasks. In a study-test associative recognition memory paradigm, we employed encoding conditions that established unitized representations of two pre-experimentally unrelated words, e.g. vegetable-bible. We compared event-related potentials (ERP) during the retrieval of these unitized word pairs using different retrieval cues. Word pairs presented in the same order as during unitization at encoding elicited a parietally distributed early old/new effect which we interpret as reflecting conceptually driven familiarity for newly formed concepts. Conversely, word pairs presented in reversed order only elicited a topographically dissociable early effect, i.e. the mid-frontal old/new effect, the putative correlate of experimental familiarity. The late parietal old/new effect, the putative ERP correlate of recollection, was obtained irrespective of word order, though it was larger for words presented in same order. These results indicate that familiarity may not be a unitary process and that different task demands can promote the assessment of conceptually driven familiarity for novel unitized concepts or experimentally-induced increments of experimental familiarity, respectively. Copyright © 2010 Elsevier B.V. All rights reserved.

Impact of an inquiry unit on grade 4 students' science learning

NASA Astrophysics Data System (ADS)

Di Mauro, María Florencia; Furman, Melina

2016-09-01

This paper concerns the identification of teaching strategies that enhance the development of 4th grade students' experimental design skills at a public primary school in Argentina. Students' performance in the design of relevant experiments was evaluated before and after an eight-week intervention compared to a control group, as well as the persistence of this learning after eight months. The study involved a quasi-experimental longitudinal study with pre-test/post-test/delayed post-test measures, complemented with semi-structured interviews with randomly selected students. Our findings showed improvement in the experimental design skills as well as its sustainability among students working with the inquiry-based sequence. After the intervention, students were able to establish valid comparisons, propose pertinent designs and identify variables that should remain constant. Contrarily, students in the control group showed no improvement and continued to solve the posed problems based on prior beliefs. In summary, this paper shows evidence that implementing inquiry-based units involving problems set in cross-domain everyday situations that combine independent student work with teacher guidance significantly improves the development of scientific skills in real classroom contexts.

Tracking motor units longitudinally across experimental sessions with high‐density surface electromyography

PubMed Central

Martinez‐Valdes, E.; Negro, F.; Laine, C. M.; Falla, D.; Mayer, F.

2017-01-01

Key points Classic motor unit (MU) recording and analysis methods do not allow the same MUs to be tracked across different experimental sessions, and therefore, there is limited experimental evidence on the adjustments in MU properties following training or during the progression of neuromuscular disorders.We propose a new processing method to track the same MUs across experimental sessions (separated by weeks) by using high‐density surface electromyography.The application of the proposed method in two experiments showed that individual MUs can be identified reliably in measurements separated by weeks and that changes in properties of the tracked MUs across experimental sessions can be identified with high sensitivity.These results indicate that the behaviour and properties of the same MUs can be monitored across multiple testing sessions.The proposed method opens new possibilities in the understanding of adjustments in motor unit properties due to training interventions or the progression of pathologies. Abstract A new method is proposed for tracking individual motor units (MUs) across multiple experimental sessions on different days. The technique is based on a novel decomposition approach for high‐density surface electromyography and was tested with two experimental studies for reliability and sensitivity. Experiment I (reliability): ten participants performed isometric knee extensions at 10, 30, 50 and 70% of their maximum voluntary contraction (MVC) force in three sessions, each separated by 1 week. Experiment II (sensitivity): seven participants performed 2 weeks of endurance training (cycling) and were tested pre–post intervention during isometric knee extensions at 10 and 30% MVC. The reliability (Experiment I) and sensitivity (Experiment II) of the measured MU properties were compared for the MUs tracked across sessions, with respect to all MUs identified in each session. In Experiment I, on average 38.3% and 40.1% of the identified MUs could be tracked across two sessions (1 and 2 weeks apart), for the vastus medialis and vastus lateralis, respectively. Moreover, the properties of the tracked MUs were more reliable across sessions than those of the full set of identified MUs (intra‐class correlation coefficients ranged between 0.63—0.99 and 0.39–0.95, respectively). In Experiment II, ∼40% of the MUs could be tracked before and after the training intervention and training‐induced changes in MU conduction velocity had an effect size of 2.1 (tracked MUs) and 1.5 (group of all identified motor units). These results show the possibility of monitoring MU properties longitudinally to document the effect of interventions or the progression of neuromuscular disorders. PMID:28032343

On the Hedges Correction for a "t"-Test

ERIC Educational Resources Information Center

VanHoudnos, Nathan M.; Greenhouse, Joel B.

2016-01-01

When cluster randomized experiments are analyzed as if units were independent, test statistics for treatment effects can be anticonservative. Hedges proposed a correction for such tests by scaling them to control their Type I error rate. This article generalizes the Hedges correction from a posttest-only experimental design to more common designs…

The History and Implications of Design Standards for Underwater Breathing Apparatus - 1954 to 2015

DTIC Science & Technology

2015-02-11

respiratory loading using both simple models of fluid mechanics and experimental evidence. An understanding of the influence of both respiratory ventilatory... fluid dynamics of flow in divers’ airways. It allows testing laboratories to make maximum use of all of their testing data, and lo present that data in...tireless efforts of numerous military divers at Navy Experimental Diving Unit in Panama City, FL and Naval Medical Research Institute, Bethesda, MD

Interactive Technology and Engaging Learners in the Mathematics Classroom

ERIC Educational Resources Information Center

Camara, Phyllis

2013-01-01

The Program for International Assessment tested students in mathematics from 41 countries and found that students in the United States ranked in the lowest percentile. This struggle with math among youth in the United States prompted this quasi-experimental quantitative study about using interactive technology to engage and motivate 9th grade…

Effects of the Integrated Online Advance Organizer Teaching Materials on Students' Science Achievement and Attitude

ERIC Educational Resources Information Center

Korur, Fikret; Toker, Sacip; Eryilmaz, Ali

2016-01-01

This two-group quasi-experimental study investigated the effects of the Online Advance Organizer Concept Teaching Material (ONACOM) integrated with inquiry teaching and expository teaching methods. Grade 7 students' posttest performances on the light unit achievement and light unit attitude tests controlled for gender, previous semester science…

A Game Plan for Teaching Logic.

ERIC Educational Resources Information Center

Woloshin, Phyllis Lerman

An experiment using game-theory to teach a unit on "fallacies" in logic was conducted at Oakton Community College. One experimental and two control group lecture-style classes were taught by three teachers using the same text and final test. The experimental class, after an introductory segment presented in lecture style, were involved in a…

Prompting children to reason proportionally: Processing discrete units as continuous amounts.

PubMed

Boyer, Ty W; Levine, Susan C

2015-05-01

Recent studies reveal that children can solve proportional reasoning problems presented with continuous amounts that enable intuitive strategies by around 6 years of age but have difficulties with problems presented with discrete units that tend to elicit explicit count-and-match strategies until at least 10 years of age. The current study tests whether performance on discrete unit problems might be improved by prompting intuitive reasoning with continuous-format problems. Participants were kindergarten, second-grade, and fourth-grade students (N = 194) assigned to either an experimental condition, where they were given continuous amount proportion problems before discrete unit proportion problems, or a control condition, where they were given all discrete unit problems. Results of a three-way mixed-model analysis of variance examining school grade, experimental condition, and block of trials indicated that fourth-grade students in the experimental condition outperformed those in the control condition on discrete unit problems in the second half of the experiment, but kindergarten and second-grade students did not differ by condition. This suggests that older children can be prompted to use intuitive strategies to reason proportionally. (c) 2015 APA, all rights reserved).

Thermal-hydraulics modeling for prototype testing of the W7-X high heat flux scraper element

DOE PAGES

Clark, Emily; Lumsdaine, Arnold; Boscary, Jean; ...

2017-07-28

The long-pulse operation of the Wendelstein 7-X (W7-X) stellarator experiment is scheduled to begin in 2020. This operational phase will be equipped with water-cooled plasma facing components to allow for longer pulse durations. Certain simulated plasma scenarios have been shown to produce heat fluxes that surpass the technological limits on the edges of the divertor target elements during steady-state operation. In order to reduce the heat load on the target elements, the addition of a “scraper element” (SE) is under investigation. The SE is composed of 24 water-cooled carbon fiber reinforced carbon composite monoblock units. Multiple full-scale prototypes have beenmore » tested in the GLADIS high heat flux test facility. Previous computational studies revealed discrepancies between the simulations and experimental measurements. In this work, single-phase thermal-hydraulics modeling was performed in ANSYS CFX to identify potential causes for such discrepancies. Possible explanations investigated were the effects of a non-uniform thermal contact resistance and a potential misalignment of the monoblock fibers. And while the difference between the experimental and computational results was not resolved by a non-uniform thermal contact resistance, the computational results provided insight into the potential performance of a W7-X monoblock unit. Circumferential temperature distributions highlighted the expected boiling regions of such a unit. Finally, simulations revealed that modest angles of fiber misalignment in the monoblocks result in asymmetries at the unit edges and provide temperature differences similar to the experimental results.« less

Thermal-hydraulics modeling for prototype testing of the W7-X high heat flux scraper element

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

Clark, Emily; Lumsdaine, Arnold; Boscary, Jean

The long-pulse operation of the Wendelstein 7-X (W7-X) stellarator experiment is scheduled to begin in 2020. This operational phase will be equipped with water-cooled plasma facing components to allow for longer pulse durations. Certain simulated plasma scenarios have been shown to produce heat fluxes that surpass the technological limits on the edges of the divertor target elements during steady-state operation. In order to reduce the heat load on the target elements, the addition of a “scraper element” (SE) is under investigation. The SE is composed of 24 water-cooled carbon fiber reinforced carbon composite monoblock units. Multiple full-scale prototypes have beenmore » tested in the GLADIS high heat flux test facility. Previous computational studies revealed discrepancies between the simulations and experimental measurements. In this work, single-phase thermal-hydraulics modeling was performed in ANSYS CFX to identify potential causes for such discrepancies. Possible explanations investigated were the effects of a non-uniform thermal contact resistance and a potential misalignment of the monoblock fibers. And while the difference between the experimental and computational results was not resolved by a non-uniform thermal contact resistance, the computational results provided insight into the potential performance of a W7-X monoblock unit. Circumferential temperature distributions highlighted the expected boiling regions of such a unit. Finally, simulations revealed that modest angles of fiber misalignment in the monoblocks result in asymmetries at the unit edges and provide temperature differences similar to the experimental results.« less

The effect of inquiry based science instruction on student understanding

NASA Astrophysics Data System (ADS)

Nail, Jessica Lynette

According to the TIMSS Study (2007), the United States is falling behind in the subjects of math and science. In order for the students in the United States to develop scientific literacy and remain competitive globally, inquiry must be the priority when teaching science (NRC, 1996; AAAS, 1990). The main purpose of this research was to see if inquiry-based instruction in the science classroom had a significant effect on student understanding and retention of information in a rural school in Virginia. The effect of inquiry-based science instruction on gender was also examined. The researcher implemented a four-week, inquiry-based unit on Virginia Sol 6.7, written in the 5 E learning style to 358 sixth-grade students and compared their posttest gains and delayed posttest scores to a control group consisting of 268 students. The control group received traditional teaching methods. The results for the posttest gains produced a p = 0.01. Therefore, there was a significant difference in the experimental group, which received the treatment, when compared to the control group, which did not receive treatment. A t test was also used to compare the delayed test scores of the experimental group to the control group. The results showed a p < 0.0001 when comparing the experimental group, which received the four-week inquiry-based science instruction treatment, to the control, which did not receive the treatment. This t test showed a very highly significant difference between the experimental group and the control group. Based on these results, it is imperative that Virginia begin implementing inquiry-based instruction in the science classroom.

Damage Precursor Detection in Polymer Matrix Composites Using Novel Smart Composite Particles

DTIC Science & Technology

2016-09-20

during the deformation test. Good agreement was observed with experimental results : the intensity of fluorescence was found to be directly proportional to...agreement is observed with experimental results , for which the intensity of fluorescence was found to be directly proportional to the deformation. Epoxy...the estimated Tgs of both neat epoxy and the smart polymer were compared with the experimental results obtained by DSC. Unit cell preparation

Counter-Attrition Programs in the United States Armed Forces

DTIC Science & Technology

1984-07-01

the average pretest - posttest improvement of ART students on the Gates-MacGinitie Reading Test was 2.5 RGL. No comparison control group change scores...retraining programs, elaborate quasi - experimentation could be readily built Into the existing operational system. Every major installation has one or more...research on teach-n. Chicago: Rand McNally, 1963, pp. 171-246. Reprinted as Experimental and quasi - experimental designs for research. Chicago: Rand

Detection and analysis of part load and full load instabilities in a real Francis turbine prototype

NASA Astrophysics Data System (ADS)

Presas, Alexandre; Valentin, David; Egusquiza, Eduard; Valero, Carme

2017-04-01

Francis turbines operate in many cases out of its best efficiency point, in order to regulate their output power according to the instantaneous energy demand of the grid. Therefore, it is of paramount importance to analyse and determine the unstable operating points for these kind of units. In the framework of the HYPERBOLE project (FP7-ENERGY-2013-1; Project number 608532) a large Francis unit was investigated numerically, experimentally in a reduced scale model and also experimentally and numerically in the real prototype. This paper shows the unstable operating points identified during the experimental tests on the real Francis unit and the analysis of the main characteristics of these instabilities. Finally, it is shown that similar phenomena have been identified on previous research in the LMH (Laboratory for Hydraulic Machines, Lausanne) with the reduced scale model.

Initial comparison of single cylinder Stirling engine computer model predictions with test results

NASA Technical Reports Server (NTRS)

Tew, R. C., Jr.; Thieme, L. G.; Miao, D.

1979-01-01

A NASA developed digital computer code for a Stirling engine, modelling the performance of a single cylinder rhombic drive ground performance unit (GPU), is presented and its predictions are compared to test results. The GPU engine incorporates eight regenerator/cooler units and the engine working space is modelled by thirteen control volumes. The model calculates indicated power and efficiency for a given engine speed, mean pressure, heater and expansion space metal temperatures and cooler water inlet temperature and flow rate. Comparison of predicted and observed powers implies that the reference pressure drop calculations underestimate actual pressure drop, possibly due to oil contamination in the regenerator/cooler units, methane contamination in the working gas or the underestimation of mechanical loss. For a working gas of hydrogen, the predicted values of brake power are from 0 to 6% higher than experimental values, and brake efficiency is 6 to 16% higher, while for helium the predicted brake power and efficiency are 2 to 15% higher than the experimental.

Thermal measurement of brake pad lining surfaces during the braking process

NASA Astrophysics Data System (ADS)

Piątkowski, Tadeusz; Polakowski, Henryk; Kastek, Mariusz; Baranowski, Pawel; Damaziak, Krzysztof; Małachowski, Jerzy; Mazurkiewicz, Łukasz

2012-06-01

This paper presents the test campaign concept and definition and the analysis of the recorded measurements. One of the most important systems in cars and trucks are brakes. The braking temperature on a lining surface can rise above 500°C. This shows how linings requirements are so strict and, what is more, continuously rising. Besides experimental tests, very supportive method for investigating processes which occur on the brake pad linings are numerical analyses. Experimental tests were conducted on the test machine called IL-68. The main component of IL-68 is so called frictional unit, which consists of: rotational head, which convey a shaft torque and where counter samples are placed and translational head, where samples of coatings are placed and pressed against counter samples. Due to the high rotational speeds and thus the rapid changes in temperature field, the infrared camera was used for testing. The paper presents results of analysis registered thermograms during the tests with different conditions. Furthermore, based on this testing machine, the numerical model was developed. In order to avoid resource demanding analyses only the frictional unit (described above) was taken into consideration. Firstly the geometrical model was performed thanks to CAD techniques, which in the next stage was a base for developing the finite element model. Material properties and boundary conditions exactly correspond to experimental tests. Computations were performed using a dynamic LS-Dyna code where heat generation was estimated assuming full (100%) conversion of mechanical work done by friction forces. Paper presents the results of dynamic thermomechanical analysis too and these results were compared with laboratory tests.

Final construction and testing of an experimental sprinkler/groundwater treatment system for proposed use by the village of Utica, Nebraska.

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

NONE

2005-06-17

The testing described above demonstrates that the experimental sprinkler designed by Argonne could be successfully, and safely, used by the Village of Utica for irrigation of the town's playing fields, using contaminated (by carbon tetrachloride) groundwater from the shallow aquifer beneath the town. Routine operation of the sprinkler within the range of parameters identified by the testing program would effectively reduce carbon tetrachloride concentrations in the discharged spray reaching the ground to levels below the MCL (5 {micro}g/l). CCC/USDA and Argonne propose to test use of the experimental sprinkler by the Village of Utica during the next (Summer 2001) growingmore » season, under Argonne supervision. Water will be supplied from the well to the sprinkler drive unit using a temporary, flexible (high-pressure hose) connection. Argonne will provide training to Village staff in the setup and use of the sprinkler, and will conduct periodic monitoring (proposed biweekly, initially) of the watering operations and sampling and analysis of the spray discharge from the unit, to ensure that the specified groundwater cleanup performance of the sprinkler system (to carbon tetrachloride values <5 {micro}g/L) is maintained. If testing of the sprinkler in this manner proves successful during 2001, CCC/USDA will seek to permanently transfer ownership and operation responsibilities for the sprinkler to the Utica Village Board.« less

Simulation, Model Verification and Controls Development of Brayton Cycle PM Alternator: Testing and Simulation of 2 KW PM Generator with Diode Bridge Output

NASA Technical Reports Server (NTRS)

Stankovic, Ana V.

2003-01-01

Professor Stankovic will be developing and refining Simulink based models of the PM alternator and comparing the simulation results with experimental measurements taken from the unit. Her first task is to validate the models using the experimental data. Her next task is to develop alternative control techniques for the application of the Brayton Cycle PM Alternator in a nuclear electric propulsion vehicle. The control techniques will be first simulated using the validated models then tried experimentally with hardware available at NASA. Testing and simulation of a 2KW PM synchronous generator with diode bridge output is described. The parameters of a synchronous PM generator have been measured and used in simulation. Test procedures have been developed to verify the PM generator model with diode bridge output. Experimental and simulation results are in excellent agreement.

Watergate: A Teaching Unit. Curriculum Project Report No. 4040. Experimental Edition.

ERIC Educational Resources Information Center

Malament, Elizabeth E.

Because Watergate tested the strength of the U.S. constitutional system and proved that it worked, this unit could serve as a focal point for study of the U.S. Constitution. The three objectives of the document are: (1) to expand knowledge of the governance process through study of the separation of powers, the impeachment process, the right to…

Me and My Environment. Unit IV: Transfer and Cycling of Materials in My Environment.

ERIC Educational Resources Information Center

Biological Sciences Curriculum Study, Boulder, CO.

Presented is the experimental edition of Unit IV: Transfer and Cycling of Materials in My Environment, which consists of 29 life science curriculum activities intended for the 13-to-15-year-old educable mentally retarded child. The curriculum guide is being used in the final field test prior to revision. Stressed throughout the program are…

Land and Undersea Field Testing of Very Low Frequency RF Antennas and Loop Transceivers

DTIC Science & Technology

2017-12-01

VLF RF HARDWARE: SSC PACIFIC LOOP ANTENNAS ........................................... 4 2.3 EXPERIMENTAL CONCEPT...2.3 EXPERIMENTAL CONCEPT Figure 5 shows a drawing of a typical transmit/receive scenario. Each of the WFS units and loop antennas can both transmit...kilohertz is around 20 fT/root(Hz). One femtoTesla (fT) is equal to 10-15 Tesla. Our derived value is close to the 30 fT/root(Hz) value experimentally

Novel exposure units for at-home personalized testing of electromagnetic sensibility.

PubMed

Huss, Anke; Murbach, Manuel; van Moorselaar, Imke; Kuster, Niels; van Strien, Rob; Kromhout, Hans; Vermeulen, Roel; Slottje, Pauline

2016-01-01

Previous experimental studies on electromagnetic hypersensitivity have been criticized regarding inflexibility of choice of exposure and of study locations. We developed and tested novel portable exposure units that can generate different output levels of various extremely low frequency magnetic fields (ELF-MF; 50 Hz field plus harmonics) and radiofrequency electromagnetic fields (RF-EMF). Testing was done with a group of healthy volunteers (n = 25 for 5 ELF-MF and n = 25 for 5 RF-EMF signals) to assess if units were indeed able to produce double-blind exposure conditions. Results substantiated that double-blind conditions were met; on average participants scored 50.6% of conditions correct on the ELF-MF, and 50.0% on the RF-EMF unit, which corresponds to guessing probability. No cues as to exposure conditions were reported. We aim to use these units in a future experiment with subjects who wish to test their personal hypothesis of being able to sense or experience when being exposed to EMF. The new units allow for a high degree of flexibility regarding choice of applied electromagnetic signal, output power level and location (at home or another environment of subjects' choosing). © 2015 Wiley Periodicals, Inc.

Ecosystem nutrient responses to chronic nittogen inputs at Fernow Experimental Forest, West Virginia

Treesearch

Frank S. ​Gilliam; Mary Beth Adams; Bradley M. Yurish

1996-01-01

Among the current environmental concerns for forests of the eastern United States is nitrogen (N) saturation, a result of excessive inputs of N associated with acidic deposition. We studied nutrient responses on N-treated and untreated watersheds of the Fernow Experimental Forest, West Virginia, to test for evidence of N saturation on the treated watershed. The...

Fighting The Network: Manet Management In Support Of Littoral Operations

DTIC Science & Technology

2016-03-01

Solomon , 2015). DL widens the scope of naval Surface Action Groups (SAG) operations, introducing the concept of Adaptive Force Package (AFP...be implemented in littoral tactical networks. CENETIX research utilizes three Wave Relay radio models for experimentation : the Man-Portable Unit...enable seamless continuity in the transfer of research knowledge to subsequent testing and CONOPS development. CENETIX field experimentation

BDPU, Favier places new test chamber into experiment module in LMS-1 Spacelab

NASA Image and Video Library

1996-07-09

STS078-301-021 (20 June - 7 July 1996) --- Payload specialist Jean-Jacques Favier, representing the French Space Agency (CNES), holds up a test container to a Spacelab camera. The test involves the Bubble Drop Particle Unit (BDPU), which Favier is showing to ground controllers at the Marshall Space Flight Center (MSFC) in order to check the condition of the unit prior to heating in the BDPU facility. The test container holds experimental fluid and allows experiment observation through optical windows. BDPU contains three internal cameras that are used to continuously downlink BDPU activity so that behavior of the bubbles can be monitored. Astronaut Richard M. Linnehan, mission specialist, conducts biomedical testing in the background.

Testing a passive revegetation approach for restoring coastal plain depression wetlands

Treesearch

Diane De Steven; Rebecca R. Sharitz; Julian H. Singer; Christopher D. Barton

2006-01-01

Restoration of coastal plain depressions, a biologically significant and threatened wetland type of the southeastern United States, has received little systematic research. Within the context of an experimental project designed to evaluate several restoration approaches, we tested whether successful revegetation can be achieved by passive methods (recruitment from seed...

Larval aquatic insect responses to cadmium and zinc in experimental streams.

PubMed

Mebane, Christopher A; Schmidt, Travis S; Balistrieri, Laurie S

2017-03-01

To evaluate the risks of metal mixture effects to natural stream communities under ecologically relevant conditions, the authors conducted 30-d tests with benthic macroinvertebrates exposed to cadmium (Cd) and zinc (Zn) in experimental streams. The simultaneous exposures were with Cd and Zn singly and with Cd+Zn mixtures at environmentally relevant ratios. The tests produced concentration-response patterns that for individual taxa were interpreted in the same manner as classic single-species toxicity tests and for community metrics such as taxa richness and mayfly (Ephemeroptera) abundance were interpreted in the same manner as with stream survey data. Effect concentrations from the experimental stream exposures were usually 2 to 3 orders of magnitude lower than those from classic single-species tests. Relative to a response addition model, which assumes that the joint toxicity of the mixtures can be predicted from the product of their responses to individual toxicants, the Cd+Zn mixtures generally showed slightly less than additive toxicity. The authors applied a modeling approach called Tox to explore the mixture toxicity results and to relate the experimental stream results to field data. The approach predicts the accumulation of toxicants (hydrogen, Cd, and Zn) on organisms using a 2-pK a bidentate model that defines interactions between dissolved cations and biological receptors (biotic ligands) and relates that accumulation through a logistic equation to biological response. The Tox modeling was able to predict Cd+Zn mixture responses from the single-metal exposures as well as responses from field data. The similarity of response patterns between the 30-d experimental stream tests and field data supports the environmental relevance of testing aquatic insects in experimental streams. Environ Toxicol Chem 2017;36:749-762. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Structural Solutions for Low-Cost Bamboo Frames: Experimental Tests and Constructive Assessments

PubMed Central

Sassu, Mauro; De Falco, Anna; Giresini, Linda; Puppio, Mario Lucio

2016-01-01

Experimental tests and constructive assessments are presented for a simple bamboo framed structure with innovative low-cost and low technology joints, specifically conceived for small buildings in developing countries. Two full scale one-storey bamboo frames have been designed by using the simplest joints solution among three different tested typologies. The entire building process is based on low-technology and natural materials: bamboo canes, wooden cylinders, plywood plates and canapé rods. The first full scale specimen (Unit A) is a one-storey single deck truss structure subjected to monotonic collapse test; the second full scale specimen (Unit B) is a one-storey double deck truss structure used to evaluate the construction time throughout assembling tests. The first full scale specimen showed ductility in collapse and ease in strengthening; the second one showed remarkable ease and speed in assembling structural elements. Finally several constructive solutions are suggested for the design of simple one-storey buildings; they are addressed to four purposes (housing, school, chapel, health center) by the composition of the proposed full scale bamboo frames. Ease of use and maintenance with a low level of technology contribute to application in developing countries although not exclusively. PMID:28773472

Authorized Course of Instruction for the Quinmester Program. Science: Scientific Approach to Solving Problems; Who's Who; and What in the World's Going On.

ERIC Educational Resources Information Center

Dade County Public Schools, Miami, FL.

Performance objectives are stated for each of the three secondary school units included in this package prepared for the Dade County Florida Quinmester Program. The units all concern some aspect of instruction in scientific method. "The Scientific Approach to Solving Problems" introduces students to the use of experimental testing of…

Engine-Scale Combustor Rig Designed, Fabricated, and Tested for Combustion Instability Control Research

NASA Technical Reports Server (NTRS)

DeLaat, John C.; Breisacher, Kevin J.

2000-01-01

Low-emission combustor designs are prone to combustor instabilities. Because active control of these instabilities may allow future combustors to meet both stringent emissions and performance requirements, an experimental combustor rig was developed for investigating methods of actively suppressing combustion instabilities. The experimental rig has features similar to a real engine combustor and exhibits instabilities representative of those in aircraft gas turbine engines. Experimental testing in the spring of 1999 demonstrated that the rig can be tuned to closely represent an instability observed in engine tests. Future plans are to develop and demonstrate combustion instability control using this experimental combustor rig. The NASA Glenn Research Center at Lewis Field is leading the Combustion Instability Control program to investigate methods for actively suppressing combustion instabilities. Under this program, a single-nozzle, liquid-fueled research combustor rig was designed, fabricated, and tested. The rig has many of the complexities of a real engine combustor, including an actual fuel nozzle and swirler, dilution cooling, and an effusion-cooled liner. Prior to designing the experimental rig, a survey of aircraft engine combustion instability experience identified an instability observed in a prototype engine as a suitable candidate for replication. The frequency of the instability was 525 Hz, with an amplitude of approximately 1.5-psi peak-to-peak at a burner pressure of 200 psia. The single-nozzle experimental combustor rig was designed to preserve subcomponent lengths, cross sectional area distribution, flow distribution, pressure-drop distribution, temperature distribution, and other factors previously found to be determinants of burner acoustic frequencies, mode shapes, gain, and damping. Analytical models were used to predict the acoustic resonances of both the engine combustor and proposed experiment. The analysis confirmed that the test rig configuration and engine configuration had similar longitudinal acoustic characteristics, increasing the likelihood that the engine instability would be replicated in the rig. Parametric analytical studies were performed to understand the influence of geometry and condition variations and to establish a combustion test plan. Cold-flow experiments verified that the design values of area and flow distributions were obtained. Combustion test results established the existence of a longitudinal combustion instability in the 500-Hz range with a measured amplitude approximating that observed in the engine. Modifications to the rig configuration during testing also showed the potential for injector independence. The research combustor rig was developed in partnership with Pratt & Whitney of West Palm Beach, Florida, and United Technologies Research Center of East Hartford, Connecticut. Experimental testing of the combustor rig took place at United Technologies Research Center.

New Media for Instruction: Survey of Educational Media Research in the Far East. Instructional Uses and Research Direction. Bulletin, 1963, No. 40. OE-34025

ERIC Educational Resources Information Center

Duke, Benjamin C., Ed.

1963-01-01

The primary purpose of this project was to compile, translate, and publish educational media research material from the major Asian countries and to make that information available in the United States. Educational media research and experimentation is interpreted to include experimental programming, testing, evaluation, and use of all the newer…

Effect of prophylactic non-invasive mechanical ventilation on functional capacity after heart valve replacement: a clinical trial

PubMed Central

de Araújo-Filho, Amaro Afrânio; de Cerqueira-Neto, Manoel Luiz; de Assis Pereira Cacau, Lucas; Oliveira, Géssica Uruga; Cerqueira, Telma Cristina Fontes; de Santana-Filho, Valter Joviniano

2017-01-01

OBJECTIVE: During cardiac surgery, several factors contribute to the development of postoperative pulmonary complications. Non-invasive ventilation is a promising therapeutic tool for improving the functionality of this type of patient. The aim of this study is to evaluate the functional capacity and length of stay of patients in a nosocomial intensive care unit who underwent prophylactic non-invasive ventilation after heart valve replacement. METHOD: The study was a controlled clinical trial, comprising 50 individuals of both sexes who were allocated by randomization into two groups with 25 patients in each group: the control group and experimental group. After surgery, the patients were transferred to the intensive care unit and then participated in standard physical therapy, which was provided to the experimental group after 3 applications of non-invasive ventilation within the first 26 hours after extubation. For non-invasive ventilation, the positive pressure was 10 cm H2O, with a duration of 1 hour. The evaluation was performed on the 7th postoperative day/discharge and included a 6-minute walk test. The intensive care unit and hospitalization times were monitored in both groups. Brazilian Registry of Clinical Trials (REBeC): RBR number 8bxdd3. RESULTS: Analysis of the 6-minute walk test showed that the control group walked an average distance of 264.34±76 meters and the experimental group walked an average distance of 334.07±71 meters (p=0.002). The intensive care unit and hospitalization times did not differ between the groups. CONCLUSION: Non-invasive ventilation as a therapeutic resource was effective toward improving functionality; however, non-invasive ventilation did not influence the intensive care unit or hospitalization times of the studied cardiac patients. PMID:29160424

The effect of neuro-linguistic programming on occupational stress in critical care nurses

PubMed Central

HemmatiMaslakpak, Masumeh; Farhadi, Masumeh; Fereidoni, Javid

2016-01-01

Background: The use of coping strategies in reducing the adverse effects of stress can be helpful. Nero-linguistic programming (NLP) is one of the modern methods of psychotherapy. This study aimed to determine the effect of NLP on occupational stress in nurses working in critical care units of Urmia. Materials and Methods: This study was carried out quasi-experimentally (before–after) with control and experimental groups. Of all the nurses working in the critical care units of Urmia Imam Khomeini and Motahari educational/therapeutic centers, 60 people participated in this survey. Eighteen sessions of intervention were done, each for 180 min. The experimental group received NLP program (such as goal setting, time management, assertiveness skills, representational system, and neurological levels, as well as some practical and useful NLP techniques). Expanding Nursing Stress Scale (ENSS) was used as the data gathering tool. Data were analyzed using SPSS version 16. Descriptive statistics and Chi-square test, Mann–Whitney test, and independent t-test were used to analyze the data. Results: The baseline score average of job stress was 120.88 and 121.36 for the intervention and control groups, respectively (P = 0.65). After intervention, the score average of job stress decreased to 64.53 in the experimental group while that of control group remained relatively unchanged (120.96). Mann–Whitney test results showed that stress scores between the two groups was statistically significant (P = 0.0001). Conclusions: The results showed that the use of NLP can increase coping with stressful situations, and it can reduce the adverse effects of occupational stress. PMID:26985221

IMPLEMENTING PRACTICAL PICO-HYDROPOWER

EPA Science Inventory

Deliverables for this proposal will be energy output data modeled from experimental testing of the hydropower unit and monitoring of the stormwater handling infrastructure in the GIS building; along with a design and engineering plan for implementation and building integrat...

CSP cogeneration of electricity and desalinated water at the Pentakomo field facility

NASA Astrophysics Data System (ADS)

Papanicolas, C. N.; Bonanos, A. M.; Georgiou, M. C.; Guillen, E.; Jarraud, N.; Marakkos, C.; Montenon, A.; Stiliaris, E.; Tsioli, E.; Tzamtzis, G.; Votyakov, E. V.

2016-05-01

The Cyprus Institute's Pentakomo Field Facility (PFF) is a major infrastructure for research, development and testing of technologies relating to concentrated solar power (CSP) and solar seawater desalination. It is located at the south coast of Cyprus near the sea and its environmental conditions are fully monitored. It provides a test facility specializing in the development of CSP systems suitable for island and coastal environments with particular emphasis on small units (<25 MWth) endowed with substantial storage, suitable for use in isolation or distributed in small power grids. The first major experiment to take place at the PFF concerns the development of a pilot/experimental facility for the co-generation of electricity and desalinated seawater from CSP. Specifically, the experimental plant consists of a heliostat-central receiver system for solar harvesting, thermal energy storage in molten salts followed by a Rankine cycle for electricity production and a multiple-effect distillation (MED) unit for desalination.

Design assessment of a 150 kWt CFBC Test Unit

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

Batu, A.; Selcuk, N.; Kulah, G.

2010-04-15

For clean and efficient energy generation from coal, the most suitable technology known to date is 'Fluidized Bed Combustion' technology. Applications of circulating fluidized bed (CFB) combustion technology have been steadily increasing in both capacity and number over the past decade. Designs of these units have been based on the combustion tests carried out in pilot scale facilities to determine the combustion and desulfurization characteristics of coal and limestone reserves in CFB conditions. Similarly, utilization of Turkish lignites in CFB boilers necessitates adaptation of CFB combustion technology to these resources. However, the design of these test units are not basedmore » on firing coals with high ash, volatile matter and sulfur contents like Turkish lignites. For this purpose, a 150 kWt CFB combustor test unit is designed and constructed in Chemical Engineering Department of Middle East Technical University, based on the extensive experience acquired at the existing 0.3 MWt Bubbling Atmospheric Fluidized Bed Combustor (AFBC) Test Rig. Following the commissioning tests, a combustion test is carried out for investigation of combustion characteristics of Can lignite in CFB conditions and for assessment of the design of test unit. Comparison of the design outputs with experimental results reveals that most of the predictions and assumptions have acceptable agreement with the operating conditions. In conclusion, the performance of 150 kWt CFBC Test Unit is found to be satisfactory to be utilized for the long term research studies on combustion and desulfurization characteristics of indigenous lignite reserves in circulating fluidized bed combustors. (author)« less

Evaluation of a new immunocapture test for the diagnosis of ovine brucellosis caused by Brucella melitensis.

PubMed

Durán-Ferrer, M; Mendoza, J; Osuna, A; Caporale, V; Lucas, A; León, L; Garrido, F

2002-11-23

A new immunocapture technique has been applied to the diagnosis of ovine brucellosis under experimental conditions. The tests were made on a serum bank derived from both young and adult ewes vaccinated conjunctivally with the Rev 1 strain at a dose of 10(8) to 10(9) colony-forming units. Adult ewes were infected experimentally two-and-a-half years after they had been vaccinated and the results were compared with an unvaccinated control group. The condition of each animal in terms of infection with Brucella melitensis was determined by clinical and bacteriological investigations. The development of the immune response was compared by the rose bengal test, the complement fixation test, the Coombs' test and the immunocapture technique for 180 days after the vaccination and for 410 days after the experimental infection, that is, the two following gestations. The results suggest that the new technique is more specific in animals vaccinated conjunctivally, regardless of their age when they were vaccinated. After the experimental infection, significantly (P < 0.05) fewer of the vaccinated sheep which were free of clinical signs and were not excreting B melitensis reacted positively to the test.

Design and test of a 10kW ORC supersonic turbine generator

NASA Astrophysics Data System (ADS)

Seume, J. R.; Peters, M.; Kunte, H.

2017-03-01

Manufactures are searching for possibilities to increase the efficiency of combustion engines by using the remaining energy of the exhaust gas. One possibility to recover some of this thermal energy is an organic Rankine cycle (ORC). For such an ORC running with ethanol, the aerothermodynamic design and test of a supersonic axial, single stage impulse turbine generator unit is described. The blade design as well as the regulation by variable partial admission is shown. Additionally the mechanical design of the directly coupled turbine generator unit including the aerodynamic sealing and the test facility is presented. Finally the results of CFD-based computations are compared to the experimental measurements. The comparison shows a remarkably good agreement between the numerical computations and the test data.

High-Impact Aerobic and Zumba Fitness on Increasing VO2MAX, Heart Rate Recovery and Skinfold Thickness

NASA Astrophysics Data System (ADS)

Suminar, T. J.; Kusnanik, N. W.; Wiriawan, O.

2018-01-01

Purpose of this study is to determine the significant effect of high-impact aerobics exercise, and Zumba fitness on increasing VO2Max, decreasing of heart rate recovery, and decreasing of skinfold thickness. A sample of this study is 30 members aerobics of student activity unit. Type of this study was quantitative by using a quasi-experimental design method. The design of this study used Matching-Only Design. Data were Analyzed by using the t test (paired t-test). The samples divided into three groups consisted of experimental group I, experimental group II, and control group. They were given a treatment for 8 weeks or 24 meeting. For the data, retrieval is done by MFT test, heart rate recovery test, and skinfold thickness test. Furthermore, the result was analyzed by using SPSS 21 series. In conclusion, significant effect of high-impact aerobics and Zumba fitness on increasing VO2Max, heart rate recovery, skinfold thickness.

Minimize Solvent Oxidation with NO X Pre-Scrubbing

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

Sexton, Andrew; Sachde, Darshan; Vance, Austyn

A novel method to remove nitrogen dioxide (NO 2) from the flue gas of coal-fired power plants with CO 2 capture was further developed for commercial implementation. The technology leverages the equipment and chemistry in an existing (sulfur dioxide) SO 2 polishing scrubber upstream of the main CO 2 capture unit to remove the NO 2, preventing degradation of the CO 2 capture solvent and formation of nitrosamines (environmental hazards). The research in this report focuses on further evaluation of the chemical additives and operating conditions associated with the NO 2 removal process to define conditions for commercial scale testingmore » and deployment. Experimental work systematically evaluated a series of potential additives to minimize the oxidation of sulfite in a representative SO 2 pre-scrubber solution (sulfite, in turn, absorbs NO 2). The additive combinations and concentrations were varied alongside important process conditions such as temperature, oxygen concentration, and metals present in solution to mimic the conditions expected in a commercial system. Important results of the parametric experimental work include identifying a new, potent sulfite oxidation inhibitor, revealing the importance of combining inhibitors with metal chelating agents, validation of a low-cost additive process, and development of a new semi-empirical model to represent mechanisms associated with sulfite oxidation. In addition, the experimental work reveled the impact of operating at higher temperatures (representative of a field test unit), which will guide the selection and concertation of additives as well. Engineering analysis found that waste solutions from the pre-scrubber with NO 2 additives may potentially be integrated with existing processes on site (e.g., flue gas desulfurization unit). In addition, techno-economic analysis identified potential net savings as large as $1.30/tonne CO 2 captured and quantified the potential benefit of low cost additive options actively being pursued by the development team. Finally, the experimental results and engineering analysis supported the development of a detailed field testing plan and protocol to evaluate the technology at near-commercial scale. The field test preparation included development of procedures to introduce chemical additives to an existing SO 2 polishing unit and identification of representative flue gas conditions based on a review of existing plants. These activities will have direct bearing on operation and design of commercial units.« less

A Module Experimental Process System Development Unit (MEPSDU)

NASA Technical Reports Server (NTRS)

1981-01-01

Subsequent to the design review, a series of tests was conducted on simulated modules to demonstrate that all environmental specifications (wind loading, hailstone impact, thermal cycling, and humidity cycling) are satisfied by the design. All tests, except hailstone impact, were successfully completed. The assembly sequence was simplified by virtue of eliminating the frame components and assembly steps. Performance was improved by reducing the module edge border required to accommodate the frame of the preliminary design module. An ultrasonic rolling spot bonding technique was selected for use in the machine to perform the aluminum interconnect to cell metallization electrical joints required in the MEPSDU module configuration. This selection was based on extensive experimental tests and economic analyses.

SCI 236 AGARDograph. Part Two; National Aeronautics and Space Administration Armstrong Flight Research Center Annex

NASA Technical Reports Server (NTRS)

Neal, Bradford A.; Stoliker, Patrick C.

2018-01-01

NASA AFRC is a United States government entity that conducts the integration and operation of new and unproven technologies into proven flight vehicles as well as the flight test of one-of-a-kind experimental aircraft. AFRC also maintains and operates several platform aircraft that allow the integration of a wide range of sensors to conduct airborne remote sensing, science observations and airborne infrared astronomy. To support these types of operations AFRC has the organization, facilities and tools to support the experimental flight test of unique vehicles and conduct airborne sensing/observing.

Compressive Loading and Modeling of Stitched Composite Stiffeners

NASA Technical Reports Server (NTRS)

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

2016-01-01

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

Comparison of the heat generation of light curing units.

PubMed

Bagis, Bora; Bagis, Yildirim; Ertas, Ertan; Ustaomer, Seda

2008-02-01

The aim of this study was to evaluate the heat generation of three different types of light curing units. Temperature increases were recorded from a distance of 1 mm from a thermocouple to the tip of three different types of light curing units including one quartz-tungsten halogen (QTH), one plasma arc (PAC), and one light emitting diode (LED) unit. An experimental model was designed to fix the 1 mm distance between the tip of the light curing units and the thermocouple wire. Temperature changes were recorded in 10 second intervals up to 40 seconds. (10, 20, 30, and 40 seconds). Temperature measurements were repeated three times for every light curing unit after a one hour standby period. Statistical analysis of the results was performed using the analysis of variance (ANOVA) and the Bonferroni Test. The highest temperature rises (54.4+/-1.65 degrees C) occurred during activation of a PAC light curing unit for every test period (p<.05). The least temperature increase (11.8+/-1.3 degrees C) occurred with a LED curing unit for each tested period except for the measurement of the temperature rise using the QTH curing unit at the tenth second interval (p<.05). These results indicate the choice of light activation unit and curing time is important when polymerizing light activated resin based restorations to avoid any thermal damage to the pulp.

Advanced Stirling Radioisotope Generator Engineering Unit 2 (ASRG EU2) Final Assembly

NASA Technical Reports Server (NTRS)

Oriti, Salvatore M.

2015-01-01

NASA Glenn Research Center (GRC) has recently completed the assembly of a unique Stirling generator test article for laboratory experimentation. Under the Advanced Stirling Radioisotope Generator (ASRG) flight development contract, NASA GRC initiated a task to design and fabricate a flight-like generator for in-house testing. This test article was given the name ASRG Engineering Unit 2 (EU2) as it was effectively the second engineering unit to be built within the ASRG project. The intent of the test article was to duplicate Lockheed Martin's qualification unit ASRG design as much as possible to enable system-level tests not previously possible at GRC. After the cancellation of the ASRG flight development project, the decision was made to continue the EU2 build, and make use of a portion of the hardware from the flight development project. GRC and Lockheed Martin engineers collaborated to develop assembly procedures, leveraging the valuable knowledge gathered by Lockheed Martin during the ASRG development contract. The ASRG EU2 was then assembled per these procedures at GRC with Lockheed Martin engineers on site. The assembly was completed in August 2014. This paper details the components that were used for the assembly, and the assembly process itself.

ANALYSIS OF MATERIALS IN AN EXPERIMENTAL TESTING PIPE SYSTEM FOR AN INHIBITOR OF MUSSEL KILL

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

Daniel P. Molloy

2003-06-04

A comprehensive series of 16 laboratory experiments demonstrated that the presence of vinyl tubing within a recirculating pipe system was responsible for lowering zebra mussel kill following treatment with the bacterium Pseudomonas fluorescens. All vinyl tubing was replaced in all testing units with silicone tubing, and high mussel kill (>95%) was then obtained.

Measurement-based evaluation of noncomposite steel girder bridges.

DOT National Transportation Integrated Search

2000-02-01

The results from an experimental study into the behavior of noncomposite slab-on-steel girder bridges are presented. Two bridge : units were tested under increasing static loads beyond first yield of the girders with a flatbed trailer loaded with con...

Acute hepatitis B virus window-period blood donations detected by individual-donation nucleic acid testing: a report on the first two cases found and interdicted in Spain.

PubMed

González, Rocio; Echevarria, José Manuel; Avellón, Ana; Barea, Luisa; Castro, Emma

2006-07-01

Mathematical models predict that, in Spain, a significant number of blood units will be obtained during the window period of the hepatitis B virus (HBV) infection. Routine nucleic acid testing (NAT) on individual blood units may provide experimental data to evaluate such a theoretical risk. Between February and July 2005, a total of 34,631 individual units were screened for HBV DNA by a multiplex transcription-mediated amplification (TMA) test. Units that repeatedly reacted in the test, but did not react for HBV surface antigen (HBsAg), were submitted to additional testing by both molecular and conventional assays, and the donors were recalled for follow-up studies and the collection of clinical and epidemiologic data. Confirmatory testing and follow-up studies identified 2 blood units donated during the HBV infection window period (1/17,316 units studied). Sequencing of amplification products obtained by nested polymerase chain reaction (n-PCR) revealed two HBV strains from genotypes D/ayw3 and F/adw4q-, but did not identify HBsAg mutants. The HBV DNA concentration in the index donations was estimated to be below the n-PCR detection level (180 IU/mL), in both cases. One donor developed acute hepatitis 2 months after donating blood, but the other remained asymptomatic and displayed normal alanine aminotransferase levels at follow-up. The HBV infection window period is a real issue in the setting of Spanish blood transfusions. NAT of individual units by TMA would make a significant contribution to improving the safety of the blood supply in Spain. Additional studies involving a larger number of units and longer periods of time are required, however, to ascertain the true incidence of the problem in this country.

Development and fabrication of structural components for a scramjet engine

NASA Technical Reports Server (NTRS)

Buchmann, O. A.

1990-01-01

A program broadly directed toward design and development of long-life (100 hours and 1,000 cycles with a goal of 1,000 hours and 10,000 cycles) hydrogen-cooled structures for application to scramjets is presented. Previous phases of the program resulted in an overall engine design and analytical and experimental characterization of selected candidate materials and concepts. The latter efforts indicated that the basic life goals for the program can be reached with available means. The main objective of this effort was an integrated, experimental evaluation of the results of the previous program phases. The fuel injection strut was selected for this purpose, including fabrication development and fabrication of a full-scale strut. Testing of the completed strut was to be performed in a NASA-Langley wind tunnel. In addition, conceptual designs were formulated for a heat transfer test unit and a flat panel structural test unit. Tooling and fabrication procedures required to fabricate the strut were developed, and fabrication and delivery to NASA of all strut components, including major subassemblies, were completed.

Testing and Results of Vacuum Swing Adsorption Units for Spacesuit Carbon Dioxide and Humidity Control

NASA Technical Reports Server (NTRS)

McMillin, Summer; Broerman, Craig; Swickrath, Mike; Anderson, Molly

2010-01-01

A principal concern for extravehicular activity (EVA) space suits is the capability to control carbon dioxide (CO2) and humidity (H2O) for the crewmember. The release of CO2 in a confined or unventilated area is dangerous for human health and leads to asphyxiation; therefore, CO2 and H2O become leading factors in the design and development of the spacesuit. An amine-based CO2 and H2O vapor sorbent for use in pressure-swing re-generable beds has been developed by Hamilton Sundstrand. The application of solid-amine materials with vacuum swing adsorption technology has shown the capacity to concurrently manage CO2 and H2O levels through a fully regenerative cycle eliminating mission constraints imposed with non-regenerative technologies. Two prototype solid amine-based systems, known as rapid cycle amine (RCA), were designed to continuously remove CO2 and H2O vapor from a flowing ventilation stream through the use of a two-bed amine based, vacuum-swing adsorption system. The Engineering and Science Contract Group (ESCG) RCA is the first RCA unit implementing radial flow paths, whereas the Hamilton Sundstrand RCA was designed with linear flow paths. Testing was performed in a sea-level pressure environment and a reduced-pressure environment with simulated human metabolic loads in a closed-loop configuration. This paper presents the experimental results of laboratory testing for a full-size and a sub-scale test article. The testing described here characterized and evaluated the performance of each RCA unit at the required Portable Life Support Subsystem (PLSS) operating conditions. The test points simulated a range of crewmember metabolic rates. The experimental results demonstrate the ability of each RCA unit to sufficiently remove CO2 and H2O from a closed loop ambient or subambient atmosphere.

The United States Army Logistics Center Historical Summary. (RCS-HIS-6 (R2)). 1 October 1976 to 30 September 1978.

DTIC Science & Technology

1980-01-10

Experimentation (FDTE) 138 Corps Automation Requirements Baseline Identification Test (CARBIT) 138 Division Materiel Management Center (DMMC) 139 Concept...Evaluation Programs (CEP) 139 Test Design and Evaluation 140 Test and Evaluation Milestone Management System (TEMMS) 140 Manpower Analysis/Force...System (CS3) Maintenance Reporting and Management (MRM) 153 DA - Standard Port System (DASPS) 154 DA - Standard Port System - Enhancement (DASPS-E) 155 DA

Liquid propellant thermal conditioning system test program

NASA Technical Reports Server (NTRS)

Bullard, B. R.

1972-01-01

Results are presented from more than 1500 hours of testing on a liquid hydrogen thermal conditioning unit. Test parameters included: mixer and vent flow rates; tank size; ullage volume; pressurant gas; pressurant temperature; pressure level; and heat rate. Gaseous hydrogen and helium were used as pressurants. Analytical models were developed to correlate the test data and relate the performance to that anticipated in zero gravity. Experimental and theoretical results are presented which relate the variables controlling vapor condensation at a moving interface.

Effect of Multiaxial Loading on Crack Growth. Volume 2. Compilation of Experimental Data

DTIC Science & Technology

1978-12-01

3121 9. PERFORMING ORGANIZATION NAME AND ADORESS 10 . PROGRAM ELEMENT. PROJECT, TASK Northrop Corporation AREA & WORK UNIT NUMBERS Aircraft Group 3901...Stresses in the Center of the 2024-T351 9 Cruciform Specimen 9 Stress Distribution along the X-axis of the 10 Cruciform Specimen 10 Stress Distribution...Tensile Test Results for 7075-T7351 584 8 Tensile Test Results for 7075-T7351 600 9 Tensile Test Results for 2024-T351 610 10 Tensile Test Results for

75TH Field Artillery Brigade Ammunition Resupply During Operation Desert Storm

DTIC Science & Technology

1992-06-05

units. Ammunition delivery competes for these assets but usually has a significantly higher priority than general supplies. Road or rail networks ...Eckelston, Tom MAJ. Interview with author. Tape recording. Ft. Leavenworth, Kansas, 10 January 1992. Force devopment test and experimentation

Testing and Results of Vacuum Swing Adsorption Units for Spacesuit Carbon Dioxide and Humidity Control

NASA Technical Reports Server (NTRS)

McMillin, Summer D.; Broerman, Craig D.; Swickrath, Michael; Anderson, Molly

2011-01-01

A principal concern for extravehicular activity (EVA) spacesuits is the capability to control carbon dioxide (CO2) and humidity (H2O) for the crewmember. The release of CO2 in a confined or unventilated area is dangerous for human health and leads to asphyxiation; therefore, CO2 and H2O control become leading factors in the design and development of the spacesuit. An amine-based CO2 and H2O vapor sorbent for use in pressure-swing regenerable beds has been developed by Hamilton Sundstrand. The application of solidamine materials with vacuum swing adsorption technology has shown the capacity to concurrently manage CO2 and H2O levels through a fully regenerative cycle eliminating mission constraints imposed with nonregenerative technologies. Two prototype solid amine-based systems, known as rapid cycle amine (RCA), were designed to continuously remove CO2 and H2O vapor from a flowing ventilation stream through the use of a two-bed amine based, vacuum-swing adsorption system. The Engineering and Science Contract Group (ESCG) RCA implements radial flow paths, whereas the Hamilton Sundstrand RCA was designed with linear flow paths. Testing was performed in a sea-level pressure environment and a reduced-pressure environment with simulated human metabolic loads in a closed-loop configuration. This paper presents the experimental results of laboratory testing for a full-size and a sub-scale test article. The testing described here characterized and evaluated the performance of each RCA unit at the required Portable Life Support Subsystem (PLSS) operating conditions. The test points simulated a range of crewmember metabolic rates. The experimental results demonstrated the ability of each RCA unit to sufficiently remove CO2 and H2O from a closed loop ambient or sub-ambient atmosphere.

Development status of a high cooling capacity single stage pulse tube cryocooler

NASA Astrophysics Data System (ADS)

Hirayama, T.; Li, R.; Y Xu, M.; Zhu, S. W.

2017-12-01

High temperature superconducting (HTS) applications require high-capacity and high-reliability cooling solutions to keep HTS materials at temperatures of approximately 80 K. In order to meet such requirements, Sumitomo Heavy Industries, Ltd.(SHI) has been developing high cooling capacity GM-type active-buffer pulse tube cryocooler. An experimental unit was designed, built and tested. A cooling capacity of 390.5 W at 80 K, COP 0.042 was achieved with an input power of approximately 9 kW. The cold stage usually reaches a stable temperature of about 25 K within one hour starting at room temperature. Also, a simplified analysis was carried out to better understand the experimental unit. In the analysis, the regenerator, thermal conduction, heat exchanger and radiation losses were calculated. The net cooling capacity was about 80% of the PV work. The experimental results, the analysis method and results are reported in this paper.

Experimental Data for Two Different Alternator Configurations in a Solar Brayton Power System

NASA Technical Reports Server (NTRS)

Mason, Lee S.; Shaltens, Richard K.; Espinosa, William D.

1997-01-01

A solar dynamic (SD) space power system has been under test at the NASA Lewis Research Center since 1994. The SD Ground Test Demonstration (GTD) system includes a solar concentrator, heat receiver with thermal energy storage, Brayton power conversion unit, and radiator installed in a thermal-vacuum chamber with a solar simulator. The Brayton unit has been operated with two different turboalternator compressor (TAC) assemblies, one which included a Rice Lundell alternator and another which incorporated a permanent magnet (PM) alternator. The Rice alternator was part of the mini-Brayton rotating unit, designed and built during the 1970's and refurbished for the GTD. The PM TAC was a development unit from the Joint US/Russian SD Flight Project. This paper highlights the operational differences (and similarities) between the Rice and PM TAC configurations including a comparative evaluation of startup characteristics and operating performance. The two alternator configurations were tested under similar thermal conditions, as an interchangeable component within the SD system. The electrical characteristics of the two units, however, dictated the use of significantly different power conditioning and control strategies. The electrical control architectures are described and compared. Test data are presented on TAC startup and system operating performance for both configurations.

The Effects of Captioning Videos on Academic Achievement and Motivation: Reconsideration of Redundancy Principle in Instructional Videos

ERIC Educational Resources Information Center

Ozdemir, Muzaffer; Izmirli, Serkan; Sahin-Izmirli, Ozden

2016-01-01

The purpose of the present study was to investigate the effect of captioned vs. non-captioned instructional videos on the motivation and achievement. To this end, a pre-test and post-test experimental design was used on 109 sophomores from a Turkish state university. Videos with and without captions of the unit in question were prepared by the…

29 CFR Appendix C to Subpart T of... - Alternative Conditions Under § 1910.401(a)(3) for Recreational Diving Instructors and Diving...

Code of Federal Regulations, 2014 CFR

2014-07-01

... (i.e., commercially pre-packed), disposable scrubber cartridge containing a CO2-sorbent material that... permit a diver to use a dive-decompression computer designed to regulate decompression when the dive...-activity test; (ii) The RoTap shaker and nested-sieves test; (iii) The Navy Experimental Diving Unit (“NEDU...

29 CFR Appendix C to Subpart T to... - Alternative Conditions Under § 1910.401(a)(3) for Recreational Diving Instructors and Diving...

Code of Federal Regulations, 2010 CFR

2010-07-01

... (i.e., commercially pre-packed), disposable scrubber cartridge containing a CO2-sorbent material that... permit a diver to use a dive-decompression computer designed to regulate decompression when the dive...-activity test; (ii) The RoTap shaker and nested-sieves test; (iii) The Navy Experimental Diving Unit (“NEDU...

29 CFR Appendix C to Subpart T of... - Alternative Conditions Under § 1910.401(a)(3) for Recreational Diving Instructors and Diving...

Code of Federal Regulations, 2013 CFR

2013-07-01

... (i.e., commercially pre-packed), disposable scrubber cartridge containing a CO2-sorbent material that... permit a diver to use a dive-decompression computer designed to regulate decompression when the dive...-activity test; (ii) The RoTap shaker and nested-sieves test; (iii) The Navy Experimental Diving Unit (“NEDU...

29 CFR Appendix C to Subpart T to... - Alternative Conditions Under § 1910.401(a)(3) for Recreational Diving Instructors and Diving...

Code of Federal Regulations, 2011 CFR

2011-07-01

... (i.e., commercially pre-packed), disposable scrubber cartridge containing a CO2-sorbent material that... permit a diver to use a dive-decompression computer designed to regulate decompression when the dive...-activity test; (ii) The RoTap shaker and nested-sieves test; (iii) The Navy Experimental Diving Unit (“NEDU...

29 CFR Appendix C to Subpart T to... - Alternative Conditions Under § 1910.401(a)(3) for Recreational Diving Instructors and Diving...

Code of Federal Regulations, 2012 CFR

2012-07-01

... (i.e., commercially pre-packed), disposable scrubber cartridge containing a CO2-sorbent material that... permit a diver to use a dive-decompression computer designed to regulate decompression when the dive...-activity test; (ii) The RoTap shaker and nested-sieves test; (iii) The Navy Experimental Diving Unit (“NEDU...

Advanced Motor Control Test Facility for NASA GRC Flywheel Energy Storage System Technology Development Unit

NASA Technical Reports Server (NTRS)

Kenny, Barbara H.; Kascak, Peter E.; Hofmann, Heath; Mackin, Michael; Santiago, Walter; Jansen, Ralph

2001-01-01

This paper describes the flywheel test facility developed at the NASA Glenn Research Center with particular emphasis on the motor drive components and control. A four-pole permanent magnet synchronous machine, suspended on magnetic bearings, is controlled with a field orientation algorithm. A discussion of the estimation of the rotor position and speed from a "once around signal" is given. The elimination of small dc currents by using a concurrent stationary frame current regulator is discussed and demonstrated. Initial experimental results are presented showing the successful operation and control of the unit at speeds up to 20,000 rpm.

The Effect of Guided-Inquiry Instruction on 6th Grade Turkish Students' Achievement, Science Process Skills, and Attitudes Toward Science

NASA Astrophysics Data System (ADS)

Koksal, Ela Ayse; Berberoglu, Giray

2014-01-01

The purpose of this study is to investigate the effectiveness of guided-inquiry approach in science classes over existing science and technology curriculum in developing content-based science achievement, science process skills, and attitude toward science of grade level 6 students in Turkey. Non-equivalent control group quasi-experimental design was used to investigate the treatment effect. There were 162 students in the experimental group and 142 students in the control group. Both the experimental and control group students took the Achievement Test in Reproduction, Development, and Growth in Living Things (RDGLT), Science Process Skills Test, and Attitudes Toward Science Questionnaire, as pre-test and post-test. Repeated analysis of variance design was used in analyzing the data. Both the experimental and control group students were taught in RDGLT units for 22 class hours. The results indicated the positive effect of guided-inquiry approach on the Turkish students' cognitive as well as affective characteristics. The guided inquiry enhanced the experimental group students' understandings of the science concepts as well as the inquiry skills more than the control group students. Similarly, the experimental group students improved their attitudes toward science more than the control group students as a result of treatment. The guided inquiry seems a transition between traditional teaching method and student-centred activities in the Turkish schools.

The Effect of Planetariums on Teaching Specific Astronomy Concepts

NASA Astrophysics Data System (ADS)

Türk, Cumhur; Kalkan, Hüseyin

2015-02-01

This study aimed to determine students' knowledge levels related to specific astronomy concepts and the effect of a planetarium environment on teaching. The study sample included seventh-grade (12-13 years old) students. For this purpose, 240 students of various socioeconomic and cultural levels from six schools (two in the city center, two in the districts and two in the villages) were enrolled in the study. The pretest-posttest control group quasi-experimental design was used in the study. The experimental and control groups were generated by random assignment. The "Solar System and Beyond" unit was selected. In the experimental group, the unit was taught with the use of a planetarium environment, whereas the same unit was taught to the control group students in a classroom environment. A test consisting of 14 multiple-choice questions was used as the pretest and posttest at the beginning and end of the unit. The data obtained were evaluated using the SPSS 20.0 software package program. The study results showed that teaching astronomical concepts in a planetarium environment was more effective than in a classroom environment. The study also revealed that students in the planetarium-assisted group were more successful in comprehending subjects that require 3D thinking, a reference system, changing the time and observation of periodic motion than those in control group.

Model validations for low-global warming potential refrigerants in mini-split air-conditioning units

DOE PAGES

Shen, Bo; Shrestha, Som; Abdelaziz, Omar

2016-09-02

To identify low GWP (global warming potential) refrigerants to replace R-22 and R-410A, extensive experimental evaluations were conducted for multiple candidates of refrigerant at the standard test conditions and at high-ambient conditions with outdoor temperature varying from 27.8 C to 55.0 C.. In the study, R-22 was compared to propane (R-290), DR-3, ARM-20B, N-20B and R-444B in a mini-split air conditioning unit originally designed for R-22; R-410A was compared to R-32, DR-55, ARM-71A, L41-2 (R-447A) in a mini-split unit designed for R-410A. To reveal physics behind the measured performance results, thermodynamic properties of the alternative refrigerants were analysed. In addition,more » the experimental data was used to calibrate a physics-based equipment model, i.e. ORNL Heat Pump Design Model (HPDM). The calibrated model translated the experimental results to key calculated parameters, i.e. compressor efficiencies, refrigerant side two-phase heat transfer coefficients, corresponding to each refrigerant. As a result, these calculated values provide scientific insights on the performance of the alternative refrigerants and are useful for other applications beyond mini-split air conditioning units.« less

Model validations for low-global warming potential refrigerants in mini-split air-conditioning units

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

Shen, Bo; Shrestha, Som; Abdelaziz, Omar

To identify low GWP (global warming potential) refrigerants to replace R-22 and R-410A, extensive experimental evaluations were conducted for multiple candidates of refrigerant at the standard test conditions and at high-ambient conditions with outdoor temperature varying from 27.8 C to 55.0 C.. In the study, R-22 was compared to propane (R-290), DR-3, ARM-20B, N-20B and R-444B in a mini-split air conditioning unit originally designed for R-22; R-410A was compared to R-32, DR-55, ARM-71A, L41-2 (R-447A) in a mini-split unit designed for R-410A. To reveal physics behind the measured performance results, thermodynamic properties of the alternative refrigerants were analysed. In addition,more » the experimental data was used to calibrate a physics-based equipment model, i.e. ORNL Heat Pump Design Model (HPDM). The calibrated model translated the experimental results to key calculated parameters, i.e. compressor efficiencies, refrigerant side two-phase heat transfer coefficients, corresponding to each refrigerant. As a result, these calculated values provide scientific insights on the performance of the alternative refrigerants and are useful for other applications beyond mini-split air conditioning units.« less

78 FR 25565 - Controlled Import Permits

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-02

... importation into the United States of otherwise prohibited or restricted plant material for experimental... could apply to import material infected with a plant disease to test diagnostic techniques.). APHIS will... being adequate to prevent plant pest introduction. Post Entry Quarantine Under Sec. 319.37-7, certain...

Empirical study of alginate impression materials by customized proportioning system

PubMed Central

2016-01-01

PURPOSE Alginate mixers available in the market do not have the automatic proportioning unit. In this study, an automatic proportioning unit for the alginate mixer and controller software were designed and produced for a new automatic proportioning unit. With this device, it was ensured that proportioning operation could arrange weight-based alginate impression materials. MATERIALS AND METHODS The variation of coefficient in the tested groups was compared with the manual proportioning. Compression tension and tear tests were conducted to determine the mechanical properties of alginate impression materials. The experimental data were statistically analyzed using one way ANOVA and Tukey test at the 0.05 level of significance. RESULTS No statistically significant differences in modulus of elastisity (P>0.3), tensional/compresional strength (P>0.3), resilience (P>0.2), strain in failure (P>0.4), and tear energy (P>0.7) of alginate impression materials were seen. However, a decrease in the standard deviation of tested groups was observed when the customized machine was used. To verify the efficiency of the system, powder and powder/water mixing were weighed and significant decrease was observed. CONCLUSION It was possible to obtain more mechanically stable alginate impression materials by using the custom-made proportioning unit. PMID:27826387

Turbomachinery group for cold energy concept application

NASA Astrophysics Data System (ADS)

Alavi, S.; Arpi, A.; Ascani, M.; Cerri, G.; Chennaoui, L.; Manni, A.

2017-08-01

The paper discusses a special attempt to improve COP and compressor capacity. Theoretical and experimental results are presented, and they show a very positive trend. Compressor and Expander Group impellers are selected among the Car Engine Turbocharger Units. Modifications are proposed to achieve the best performance, taking the peculiar characteristics of the refrigerant into consideration. Tests have confirmed the positive saving trend, which can reach up to 22%-24% for an optimized bleed vapour generator and turbomachinery-based booster unit.

Design and fabrication of a prototype for an automatic transport system for transferring human and other wastes to an incinerator unit onboard spacecraft, phase A

NASA Technical Reports Server (NTRS)

Labak, L. J.; Remus, G. A.; Mansnerus, R.

1971-01-01

Three transport system concepts were experimentally evaluated for transferring human and nonhuman wastes from a collection site to an incineration unit onboard spacecraft. The operating parameters, merits, and shortcomings of a porous-pneumatic, nozzle-pneumatic, and a mechanical screw-feed system were determined. An analysis of the test data was made and a preliminary design of two prototype systems was prepared.

A Formative Evaluation of Me Now, Unit I, Digestion and Circulation, Life Sciences for the Educable Mentally Handicapped Intermediate Grades (11-13 years).

ERIC Educational Resources Information Center

Robinson, James T.; Tolman, Richard R.

In order to evaluate Unit I (Digestion and Circulation) of the Me Now series of Life Sciences for the Educable Mentally Handicapped, 139 students in an experimental group (mean IQ 72.04; mean CA 144.9 months) and 154 control subjects (mean IQ 70.2; mean CA 148.3 months) were pre- and post-tested following instruction in the Me Now series…

Cross-protection between experimental anti-leptospirosis bacterins

PubMed Central

Dib, Cristina Corsi; Gonçales, Amane Paldês; de Morais, Zenaide Maria; de Souza, Gisele Oliveira; Miraglia, Fabiana; Abreu, Patricia Antonia Estima; Vasconcellos, Silvio Arruda

2014-01-01

We investigated the existence of cross-protection between two anti-leptospirosis monovalent experimental bacterins produced with two strains of Leptospira serogroup Pomona: Fromm strain of serovar Kennewicky, isolated from pigs in the United States, and strain GR6 of serovar Pomona isolated from pigs in Brazil. Both were added of aluminum hydroxide as an adjuvant. Experimental bacterins were tested with the hamster potency test in order to assess protection provided against the disease and against the establishment of kidney infection. Controls were polyvalent commercial vaccine produced with Leptospira strains isolated outside Brazil, which included a representative of Pomona serovar, or Sorensen solution added of aluminum hydroxide adjuvant. The challenge was performed with cross-strains of serogroup Pomona tested in accordance with international standards established for the potency test. After 21 days of the challenge, survivors were killed to evaluate the condition of Leptospira renal carrier. Experimental bacterins protected hamsters against homologous and heterologous strains, demonstrating the existence of cross-protection. The commercial vaccine protected the hamsters challenged with both strains, but there was a high proportion of animals diagnosed as renal carriers when the challenge was performed with strain GR6, isolated from pigs in Brazil. PMID:25477946

Testing the quantum superposition principle: matter waves and beyond

NASA Astrophysics Data System (ADS)

Ulbricht, Hendrik

2015-05-01

New technological developments allow to explore the quantum properties of very complex systems, bringing the question of whether also macroscopic systems share such features, within experimental reach. The interest in this question is increased by the fact that, on the theory side, many suggest that the quantum superposition principle is not exact, departures from it being the larger, the more macroscopic the system. Testing the superposition principle intrinsically also means to test suggested extensions of quantum theory, so-called collapse models. We will report on three new proposals to experimentally test the superposition principle with nanoparticle interferometry, optomechanical devices and by spectroscopic experiments in the frequency domain. We will also report on the status of optical levitation and cooling experiments with nanoparticles in our labs, towards an Earth bound matter-wave interferometer to test the superposition principle for a particle mass of one million amu (atomic mass unit).

CSI Flight Computer System and experimental test results

NASA Technical Reports Server (NTRS)

Sparks, Dean W., Jr.; Peri, F., Jr.; Schuler, P.

1993-01-01

This paper describes the CSI Computer System (CCS) and the experimental tests performed to validate its functionality. This system is comprised of two major components: the space flight qualified Excitation and Damping Subsystem (EDS) which performs controls calculations; and the Remote Interface Unit (RIU) which is used for data acquisition, transmission, and filtering. The flight-like RIU is the interface between the EDS and the sensors and actuators positioned on the particular structure under control. The EDS and RIU communicate over the MIL-STD-1553B, a space flight qualified bus. To test the CCS under realistic conditions, it was connected to the Phase-0 CSI Evolutionary Model (CEM) at NASA Langley Research Center. The following schematic shows how the CCS is connected to the CEM. Various tests were performed which validated the ability of the system to perform control/structures experiments.

Development and fabrication of a solar cell junction processing system

NASA Technical Reports Server (NTRS)

Banker, S.

1982-01-01

Development of a pulsed electron beam subsystem, wafer transport system, and ion implanter are discussed. A junction processing system integration and cost analysis are reviewed. Maintenance of the electron beam processor and the experimental test unit of the non-mass analyzed ion implanter is reviewed.

A Module Experimental Process System Development Unit (MEPSDU)

NASA Technical Reports Server (NTRS)

1981-01-01

A cost effective process sequence and machinery for the production of flat plate photovoltaic modules are described. Cells were fabricated using the process sequence which was optimized, as was a lamination procedure. Insulator tapes and edge seal material were identified and tested. Encapsulation materials were evaluated.

Experimental comparison between R409A and R437A performance in a heat pump unit

NASA Astrophysics Data System (ADS)

Duarte, M. V.; Pires, L. C.; Silva, P. D.; Gaspar, P. D.

2017-04-01

This paper reports an experimental comparison between the use of the refrigerants R409A and R437A in a heat pump unit designed and developed to work with R12. Although the use of both refrigerants in new equipments were abolished in EU and US according the new F-Gas Regulation of EU and SNAP, they still being used as options for R12 in old equipments, especially in developing countries. Both refrigerants were studied for the same test conditions, according to two groups of tests: group A (variation of the heat source temperature) and group B (variation of refrigerant flow rate). The results obtained showed that the R437A presents a higher discharge pressure and a lower discharge temperature. The heating and cooling capacities of both refrigerants were similar, as well as the exergetic efficiency. For the group A of tests the COP of both refrigerants was similar and for the group B of tests the R409A presented an average COP 15% higher. According to the results obtained it is recommended the use of R409A in old equipments (as transition refrigerant) until the acquisition of equipments operating with refrigerants with low-GWP becomes technically and economic feasible.

Compressive Testing of Stitched Frame and Stringer Alternate Configurations

NASA Technical Reports Server (NTRS)

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

2016-01-01

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

Application of Dilute Hydrogen Peroxide Gas Technology for Continuous Room Decontamination of Multidrug-Resistant Organisms: Negative Results from A Preliminary Experimental Study

PubMed Central

Rutala, William A; Kanamori, Hajime; Gergen, Maria; Sickbert-Bennett, Emily; Anderson, Deverick; Sexton, Daniel; Weber, David J

2017-01-01

Abstract Background Healthcare room environmental surfaces can be frequently and continuously contaminated with multidrug-resistant organisms (MDROs) that can persist in the environment for a prolonged time. Here, we used a dilute hydrogen peroxide (DHP) gas system for continuous room decontamination and experimentally examined the germicidal efficacy of the new technology against MDROs. Methods DHP units were installed in ceilings of a model room and the hallway in front of the room. We tested three test organisms; methicillin-resistant staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and MDR-Acinetobacter baumannii. An estimated 100–500 CFU for each test organism was inoculated and spread separately on each Formica sheet then exposed to DHP gas released into the room air. Triplicate samples were collected at times 0, 1, 3, 5, 6, 7, 24, and 48 hours. Following incubation, the colony forming units (CFU) of the test organisms on each Rodac plate were counted. Two separate experimental trials were performed for all time points. Statistical significance between intervention and control groups at each time point was determined by the Wilcoxon test, and P < 0.05 was considered significant. Results There were no statistical differences in survival between DHP intervention and control groups except data at very few time points for each organism (i.e., for MRSA in Figure 1, P = 0.0063 at 24 hours; for VRE in Figure 2, P = 0.0163 at 1 hour, P = 0.0163 at 3 hours; for MDR-Acinetobacter in in Figure 3, P = 0.0369 at 24 hours). The survival curves between both groups for each organism intersected at around 24 hours. The DHP units maintained a germicidal concentration (<0.3ppm for all runs) that was inadequate, despite attempts to control factors that could interfere with the hydrogen peroxide gas concentration. Conclusion Our preliminary study using DHP demonstrated inactivity against MDROs on room surfaces, likely because we were unable to generate a sufficient germicidal level under our test conditions with the particular DHP units. Additional technologic modifications would be required to maintain stable and effective DHP level for continuous room decontamination in patient rooms. Disclosures D. Sexton, Centers for Disease Control and Prevention: Grant Investigator, Grant recipient. Centers for Disease Control and Prevention Foundation: Grant Investigator, Grant recipient. UpToDate: Collaborator, Royalty Recipient. D. J. Weber, PDI: Consultant, Consulting fee.

The effects of guided inquiry instruction on student achievement in high school biology

NASA Astrophysics Data System (ADS)

Vass, Laszlo

The purpose of this quantitative, quasi-experimental study was to measure the effect of a student-centered instructional method called guided inquiry on the achievement of students in a unit of study in high school biology. The study used a non-random sample of 109 students, the control group of 55 students enrolled in high school one, received teacher centered instruction while the experimental group of 54 students enrolled at high school two received student-centered, guided inquiry instruction. The pretest-posttest design of the study analyzed scores using an independent t-test, a dependent t-test (p = <.001), an ANCOVA (p = .007), mixed method ANOVA (p = .024) and hierarchical linear regression (p = <.001). The experimental group that received guided inquiry instruction had statistically significantly higher achievement than the control group.

The vacuum system reform and test of the super-critical 600mw unit

NASA Astrophysics Data System (ADS)

Yan, Tao; Wan, Zhonghai; Lu, Jin; Chen, Wen; Cai, Wen

2017-11-01

The deficiencies of the designed vacuum system of the super-critical unit is pointed out in this paper, and then it is reformed by the steam ejector. The experimental results show that the vacuum of the condenser can be improved, the coal consumption can be reduced and the plant electricity consumption can be lowered dramatically at a small cost of the steam energy consumption. Meanwhile, the water-ring vacuum pumps cavitation problems can be solved.

On the mechanisms of secondary flows in a gas vortex unit

PubMed Central

Niyogi, Kaustav; Torregrosa, Maria M.; Marin, Guy B.; Shtern, Vladimir N.

2018-01-01

The hydrodynamics of secondary flow phenomena in a disc‐shaped gas vortex unit (GVU) is investigated using experimentally validated numerical simulations. The simulation using ANSYS FLUENT® v.14a reveals the development of a backflow region along the core of the central gas exhaust, and of a counterflow multivortex region in the bulk of the disc part of the unit. Under the tested conditions, the GVU flow is found to be highly spiraling in nature. Secondary flow phenomena develop as swirl becomes stronger. The backflow region develops first via the swirl‐decay mechanism in the exhaust line. Near‐wall jet formation in the boundary layers near the GVU end‐walls eventually results in flow reversal in the bulk of the unit. When the jets grow stronger the counterflow becomes multivortex. The simulation results are validated with experimental data obtained from Stereoscopic Particle Image Velocimetry and surface oil visualization measurements. © 2018 The Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers AIChE J, 64: 1859–1873, 2018 PMID:29937545

Atomization of coal water mixtures: evaluation of fuel nozzles and a cellulose gum simulant

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

Rosfjord, T.J.

1985-03-01

An experimental evaluation of four air-assist fuel nozzles has been conducted to determine atomization levels of coal-water mixture (CWM) fuels at operating conditions simulating a high pressure combustor. Two of the nozzles were commercial units marketed for use in atmospheric burners, while two nozzles were specially designed for CWM operation in a high pressure combustor. Sprays from all four injectors were characterized in tests performed over a range of liquid and air flowrates. Most of the tests were performed using a cellulose-gum water solution prepared to match the viscosity and drip characteristics of an available CWM. Atomization data acquired frommore » a limited test series using the CWM were found to be properly represented by the gum solution data. High levels of atomization (SMD about 10 micron) were achieved by two of the nozzles - one commercial unit and one special unit - at an assist airflow level corresponding to a nozzle air-fuel ratio between 0.6 - 0.8.« less

The Experimental World Literacy Programme: A Critical Assessment.

ERIC Educational Resources Information Center

United Nations Educational, Scientific, and Cultural Organization, Paris (France).

In 1964, Unesco, the United Nations Development Programme, and the governments of 11 countries agreed to evolve an effective approach to the problem of world illiteracy, which included the implementation and testing of functional literacy activities. This report of the pilot projects and microexperiments attempts to present the lessons learned by…

Performance Characteristics of Automotive Engines in the United States : Report No. 7. Mercedes Benz Model OM617 Diesel Engine.

DOT National Transportation Integrated Search

1977-01-01

Experimental data were obtained in dynamometer tests of the Mercedes Benz Model OM617 diesel engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitroge, and smoke) at steady-state engine-operating modes. The o...

Performance Characteristics of Automotive Engines in the United States : Report No. 8. Mitsubishi Model 6DS7 Diesel Engine.

DOT National Transportation Integrated Search

1977-08-01

Experimental data were obtained in dynamometer tests of the Mitsubishi Model 6DS7 diesel engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen, and smoke) at steady-state engine operating modes. The obje...

Performance Characteristics of Automotive Engines in the United States : Report No. 10. Chevrolet (1975) 250 CID 1-BBL Engine.

DOT National Transportation Integrated Search

1977-08-01

Experimental data were obtained in dynamometer tests of a 1975 Chevrolet 250-CID, 1-bbl engine to determine fuel consumption and emissions (hydrocarbons, carbon monoxide, and oxides of nitrogen) at steady-state engine operating modes. The objective o...

Performance Characteristics of Automotive Engines in the United States : Report No. 9. Chrysler (1975) 225-CID 1-BBL Engine.

DOT National Transportation Integrated Search

1977-08-01

Experimental data were obtained in dynamometer tests of a 1975 Chrysler 225-CID, 1-bbl engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, and oxides of nitrogen) at steady-state engine operating modes. The objective of ...

Performance Characteristics of Automotive Engines in the United States : Third Series - Report No. 14 - 1978 Buick 196 CID (3.2L)

DOT National Transportation Integrated Search

1981-02-01

Experimental data were obtained in dynamometer tests of a 1978 Buick 231 CID turbocharged to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine operating modes. The objective of the prog...

Performance Characteristics of Automotive Engines in the United States : Third Series - Report No. 13 - 1977 Chrysler 318 CID (5.2L)

DOT National Transportation Integrated Search

1981-06-01

Experimental data were obtained in dynamometer tests of a 1977 Chrysler 318 CID engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine operating modes. The objective of the program...

Performance Characteristics of Automotive Engines in the United States, Third Series - Report No. 10, 1978 Honda, 98 CID (1.6 Liters)

DOT National Transportation Integrated Search

1979-02-01

Experimental data were obtained in dynamometer tests of a 1978 Honda 98 CID engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine operating modes. The objective of the program is ...

Performance Characteristics of Automotive Engines in the United States : Second Series - Report No. 4 - 1976 Chevrolet 85 CID (1.4 Liters), IV.

DOT National Transportation Integrated Search

1978-05-01

Experimental data were obtained in dynamometer tests of a 1976 Chevrolet 85 CID engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine-operating modes. The objective of the program...

Performance Characteristics of Automotive Engines in the United States : First Series - Report No. 20 - 1975 Chevrolet 350 CID (5.7 Liters) ...

DOT National Transportation Integrated Search

1978-05-01

Experimental data were obtained in dynamometer tests of a 1975 Chevrolet 350 CID engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine-operating modes. The objective of the progra...

Performance Characteristics of Automotive Engines in the United States : Report No. 11. Chrysler (1975) 318-CID 2-BBL Engine.

DOT National Transportation Integrated Search

1977-08-01

Experimental data were obtained in dynamometer tests of a 1975 Chrysler 318-CID, 2-bbl engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, and oxides of nitrogen) at steady-state engine operating modes. The objective of ...

Further follow up of mortality and incidence of cancer in men from the United Kingdom who participated in the United Kingdom's atmospheric nuclear weapon tests and experimental programmes.

PubMed Central

Darby, S C; Kendall, G M; Fell, T P; Doll, R; Goodill, A A; Conquest, A J; Jackson, D A; Haylock, R G

1993-01-01

OBJECTIVES--To study the long term effects of participation in the United Kingdom's atmospheric nuclear weapon tests and experimental programmes and to test hypotheses generated by an earlier report, including the possibility that participation in tests caused small hazards of leukaemia and multiple myeloma. DESIGN--Follow up study of mortality and cancer incidence. SUBJECTS--21,358 servicemen and civilians from the United Kingdom who participated in the tests and a control group of 22,333 non-participants. MAIN OUTCOME MEASURES--Numbers of deaths; standardised mortality ratios; relative risks of mortality from all causes and 27 types of cancer. RESULTS--During seven further years of follow up the numbers of deaths observed in participants were fewer than expected from national rates for all causes, all neoplasms, leukaemia, and multiple myeloma (standardised mortality ratios 0.86, 0.85, 0.57, and 0.46); death rates were lower than in controls (relative risks 0.99, 0.96, 0.57, and 0.57; 90% confidence intervals all included 1.00). In the period more than 10 years after the initial participation in tests the relative risk of death in participants compared with controls was near unity for all causes (relative risk 0.99 (0.95 to 1.04) and all neoplasms (0.95 (0.87 to 1.04)); it was raised for bladder cancer (2.69 (1.42 to 5.20)) and reduced for cancers of the mouth, tongue, and pharynx (0.45 (0.22 to 0.93)) and for lung cancer (0.85 (0.73 to 0.99)). For leukaemia mortality was equal to that expected from national rates but greater than in controls for both the whole follow up period (1.75 (1.01 to 3.06)) and the period 2-25 years after the tests (3.38 (1.45 to 8.25)). CONCLUSION--Participation in nuclear weapon tests had no detectable effect on expectation of life or on subsequent risk of developing cancer or other fatal diseases. The excess of leukaemia in participants compared with controls seems to be principally due to a chance deficit in the controls, but the possibility that participation in the tests may have caused a small risk of leukaemia in the early years afterwards cannot be ruled out. PMID:8274923

[A new machinability test machine and the machinability of composite resins for core built-up].

PubMed

Iwasaki, N

2001-06-01

A new machinability test machine especially for dental materials was contrived. The purpose of this study was to evaluate the effects of grinding conditions on machinability of core built-up resins using this machine, and to confirm the relationship between machinability and other properties of composite resins. The experimental machinability test machine consisted of a dental air-turbine handpiece, a control weight unit, a driving unit of the stage fixing the test specimen, and so on. The machinability was evaluated as the change in volume after grinding using a diamond point. Five kinds of core built-up resins and human teeth were used in this study. The machinabilities of these composite resins increased with an increasing load during grinding, and decreased with repeated grinding. There was no obvious correlation between the machinability and Vickers' hardness; however, a negative correlation was observed between machinability and scratch width.

Detection of asymptomatic renal Leptospira infection in abattoir slaughtered cattle in southeastern Georgia, United States

PubMed Central

Ilha, Marcia; Woldemeskel, Moges; Berghaus, Roy D; Pence, Mel E

2014-01-01

Objectives: Leptospirosis is one of the most widespread zoonotic infectious diseases affecting humans and animals. Several animal species, including cattle, can act as potential asymptomatic carriers facilitating zoonotic transmission of Leptospira. This study was conducted to assess the occurrence of asymptomatic renal Leptospira carriers among cattle slaughtered in southeastern Georgia, United States. Methods: A battery of diagnostic tests, including dark field microscopy, direct fluorescent antibody staining, polymerase chain reaction, and culture, were performed on a set of bovine kidneys (n = 37) collected from an abattoir in southeastern Georgia, United States. Virulence of a field isolate obtained from this study was tested in a hamster experimental model. Results: Motile spirochete-like structures were observed by dark field microscopy in 23 (59%) out of 37 kidney samples tested. In all, 29 samples (78%) were positive by direct fluorescent antibody staining. Only 11 (29.7%) samples by polymerase chain reaction and 3 (8.1%) by culture were positive for Leptospira sp. The isolates obtained by culture were confirmed as Leptospira borgpetersenii. Hamsters experimentally infected with one of the Leptospira field isolates obtained from this study did not show clinical signs but developed renal infection with interstitial nephritis and tubular necrosis. Conclusions: This study confirms that asymptomatic Leptospira renal infection is present among cattle in the region. Our findings underscore the need for future studies to assess the potential environmental contamination and transmission to humans in contact with infected cattle. PMID:26770734

FELASA recommendations for the health monitoring of mouse, rat, hamster, guinea pig and rabbit colonies in breeding and experimental units.

PubMed

Mähler Convenor, M; Berard, M; Feinstein, R; Gallagher, A; Illgen-Wilcke, B; Pritchett-Corning, K; Raspa, M

2014-07-01

The microbiological quality of experimental animals can critically influence animal welfare and the validity and reproducibility of research data. It is therefore important for breeding and experimental facilities to establish a laboratory animal health monitoring (HM) programme as an integrated part of any quality assurance system. FELASA has published recommendations for the HM of rodent and rabbit colonies in breeding and experimental units (Nicklas et al. Laboratory Animals, 2002), with the intention of harmonizing HM programmes. As stated in the preamble, these recommendations need to be adapted periodically to meet current developments in laboratory animal medicine. Accordingly, previous recommendations have been revised and shall be replaced by the present recommendations. These recommendations are aimed at all breeders and users of laboratory mice, rats, Syrian hamsters, guinea pigs and rabbits as well as diagnostic laboratories. They describe essential aspects of HM, such as the choice of agents, selection of animals and tissues for testing, frequency of sampling, commonly used test methods, interpretation of results and HM reporting. Compared with previous recommendations, more emphasis is put on the role of a person with sufficient understanding of the principles of HM, opportunistic agents, the use of sentinel animals (particularly under conditions of cage-level containment) and the interpretation and reporting of HM results. Relevant agents, testing frequencies and literature references are updated. Supplementary information on specific agents and the number of animals to be monitored and an example of a HM programme description is provided in the appendices. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

From Concrete to Abstract in the Measurement of Length

NASA Astrophysics Data System (ADS)

Stephanou, Andreas; Fisher, William P., Jr.

2013-09-01

The concatenation of units of length is widely viewed as the paradigmatic expression of fundamental measurement. Survey, assessment, and test scores in educational and psychological measurement are often interpreted in ways that assume a concatenation of units to have been established, even though these assumptions are rarely stated or tested. A concatenation model for measurement is shown to be equivalent to a Rasch model: any two units of measurement placed end to end must together be of the same length as either one of them added to itself. This additive principle and a concatenation model of measurement together serve as a heuristic guide for organizing two experimental approaches to calibrating instruments for measuring length. The capacity to reproduce the unit of measurement from theory with no need for repeated empirical calibration experiments, as in the geometrical bisection of the line and the resultant halving of the length measure, is highlighted as essential to demonstrating a thorough understanding of the construct.

High-Throughput Screening of Therapeutic Neural Stimulation Targets: Toward Principles of Preventing and Treating Post-Traumatic Stress Disorder

DTIC Science & Technology

2009-09-01

onset and averaged across all excited units tested (mean ± SE). 7 SUPPLEMENTAL EXPERIMENTAL PROCEDURES Virus design and production...to baseline level 355 ± 505 ms later. The level of post -light firing did not vary with repeated light exposure (p > 0.7, paired t- test comparing...High-Throughput Screening of Therapeutic Neural Stimulation Targets: Toward Principles of Preventing and Treating Post - Traumatic Stress Disorder

78 FR 25137 - Radio Experimentation and Market Trials-Streamlining Rules

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-29

...This document revises and streamlines the Commission rules to modernize the Experimental Radio Service (ERS). The rules adopted in the Report and Order updates the ERS to a more flexible framework to keep pace with the speed of modern technological change while continuing to provide an environment where creativity can thrive. To accomplish this transition, the Commission created three new types of ERS licenses--the program license, the medical testing license, and the compliance testing license--to benefit the development of new technologies, expedite their introduction to the marketplace, and unleash the full power of innovators to keep the United States at the forefront of the communications industry. The Commission's actions also modify the market trial rules to eliminate confusion and more clearly articulate its policies with respect to marketing products prior to equipment certification. The Commission believes that these actions will remove regulatory barriers to experimentation, thereby permitting institutions to move from concept to experimentation to finished product more rapidly and to more quickly implement creative problem- solving methodologies.

Stereochemical analysis of (+)-limonene using theoretical and experimental NMR and chiroptical data

NASA Astrophysics Data System (ADS)

Reinscheid, F.; Reinscheid, U. M.

2016-02-01

Using limonene as test molecule, the success and the limitations of three chiroptical methods (optical rotatory dispersion (ORD), electronic and vibrational circular dichroism, ECD and VCD) could be demonstrated. At quite low levels of theory (mpw1pw91/cc-pvdz, IEFPCM (integral equation formalism polarizable continuum model)) the experimental ORD values differ by less than 10 units from the calculated values. The modelling in the condensed phase still represents a challenge so that experimental NMR data were used to test for aggregation and solvent-solute interactions. After establishing a reasonable structural model, only the ECD spectra prediction showed a decisive dependence on the basis set: only augmented (in the case of Dunning's basis sets) or diffuse (in the case of Pople's basis sets) basis sets predicted the position and shape of the ECD bands correctly. Based on these result we propose a procedure to assign the absolute configuration (AC) of an unknown compound using the comparison between experimental and calculated chiroptical data.

A Novel Framework Based on FastICA for High Density Surface EMG Decomposition

PubMed Central

Chen, Maoqi; Zhou, Ping

2015-01-01

This study presents a progressive FastICA peel-off (PFP) framework for high density surface electromyogram (EMG) decomposition. The novel framework is based on a shift-invariant model for describing surface EMG. The decomposition process can be viewed as progressively expanding the set of motor unit spike trains, which is primarily based on FastICA. To overcome the local convergence of FastICA, a “peel off” strategy (i.e. removal of the estimated motor unit action potential (MUAP) trains from the previous step) is used to mitigate the effects of the already identified motor units, so more motor units can be extracted. Moreover, a constrained FastICA is applied to assess the extracted spike trains and correct possible erroneous or missed spikes. These procedures work together to improve the decomposition performance. The proposed framework was validated using simulated surface EMG signals with different motor unit numbers (30, 70, 91) and signal to noise ratios (SNRs) (20, 10, 0 dB). The results demonstrated relatively large numbers of extracted motor units and high accuracies (high F1-scores). The framework was also tested with 111 trials of 64-channel electrode array experimental surface EMG signals during the first dorsal interosseous (FDI) muscle contraction at different intensities. On average 14.1 ± 5.0 motor units were identified from each trial of experimental surface EMG signals. PMID:25775496

Frame-dragging effect in the field of non rotating body due to unit gravimagnetic moment

NASA Astrophysics Data System (ADS)

Deriglazov, Alexei A.; Ramírez, Walberto Guzmán

2018-04-01

Nonminimal spin-gravity interaction through unit gravimagnetic moment leads to modified Mathisson-Papapetrou-Tulczyjew-Dixon equations with improved behavior in the ultrarelativistic limit. We present exact Hamiltonian of the resulting theory and compute an effective 1/c2-Hamiltonian and leading post-Newtonian corrections to the trajectory and spin. Gravimagnetic moment causes the same precession of spin S as a fictitious rotation of the central body with angular momentum J = M/m S. So the modified equations imply a number of qualitatively new effects, that could be used to test experimentally, whether a rotating body in general relativity has null or unit gravimagnetic moment.

Steam ejector-condenser: stage I of a differential vacuum pumping station

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

Hanson, C.L.; Alger, T.W.

1981-04-01

A steam ejector-condenser unit was built and tested to produce a 10 Torr (13.3 x 10/sup 2/Pa) vacuum with a 2 cm aperture to the atmosphere. This unit is the first stage of a differential vacuum pumping station that will be used with the Experimental Test Accelerator. The accelerator's electron beam will pass through a series of openings from a high vacuum (5 x 10/sup -6/ Torr) to the atmosphere. The differential system consists of four vacuum pumping units separated by 2 cm-diam apertures. Superheated steam is injected near the final beamline orifice to reduce the quantity of atmospheric airmore » flowing into the steam ejector--condenser unit. The steam ejector in the condenser vessel is open at its center to permit passage of the accelerator beam. Five nozzles mounted in a conical array produce the ejector vacuum of 10 Torr. The ejector exhausts into the condenser and forms a barrier to air flow into the lower pressure region. This feature permits high volume cold trapping and cryopumping of water vapor in the remaining lower-pressure stages. Tests have proven that the steam ejector--condenser is a reliable operating unit and suitable for long-term, steady-state accelerator operation.« less

Supplemental treatment of air in airborne infection isolation rooms using high-throughput in-room air decontamination units.

PubMed

Bergeron, Vance; Chalfine, Annie; Misset, Benoît; Moules, Vincent; Laudinet, Nicolas; Carlet, Jean; Lina, Bruno

2011-05-01

Evidence has recently emerged indicating that in addition to large airborne droplets, fine aerosol particles can be an important mode of influenza transmission that may have been hitherto underestimated. Furthermore, recent performance studies evaluating airborne infection isolation (AII) rooms designed to house infectious patients have revealed major discrepancies between what is prescribed and what is actually measured. We conducted an experimental study to investigate the use of high-throughput in-room air decontamination units for supplemental protection against airborne contamination in areas that host infectious patients. The study included both intrinsic performance tests of the air-decontamination unit against biological aerosols of particular epidemiologic interest and field tests in a hospital AII room under different ventilation scenarios. The unit tested efficiently eradicated airborne H5N2 influenza and Mycobacterium bovis (a 4- to 5-log single-pass reduction) and, when implemented with a room extractor, reduced the peak contamination levels by a factor of 5, with decontamination rates at least 33% faster than those achieved with the extractor alone. High-throughput in-room air treatment units can provide supplemental control of airborne pathogen levels in patient isolation rooms. Copyright © 2011 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

Development of the virtual experimental bench on the basis of modernized research centrifugal compressor stage test unit with the 3D impeller.

NASA Astrophysics Data System (ADS)

Aksenov, A. A.; Danilishin, A. M.; Dubenko, A. M.; Kozhukov, Y. V.

2017-08-01

Design modernization of the centrifugal compressor stage test bench with three dimensional impeller blades was carried out for the possibility of holding a series of experimental studies of different 3D impeller models. The studies relates to the problem of joint work of the impeller and the stationary channels of the housing when carrying out works on modernization with the aim of improving the parameters of the volumetric capacity or pressure in the presence of design constraints. The object of study is the experimental single end centrifugal compressor stage with the 3D impeller. Compressor stage consists of the 3D impeller, vaneless diffuser (VLD), outlet collector - folded side scroll and downstream pipe. The drive is a DC motor 75 kW. The increase gear (multiplier) was set between the compressor and DC motor, gear ratio is i = 9.8. To obtain the characteristics of the compressor and the flow area the following values were measured: total pressure, static pressure, direction (angles) of the stream in different cross sections. Additional pneumometric probes on the front wall of the VLD of the test bench have been installed. Total pressure probes and foster holes for the measurement of total and static pressure by the new drainage scheme. This allowed carrying out full experimental studies for two elements of centrifugal compressor stage. After the experimental tests the comprehensive information about the performance of model stage were obtained. Was measured geometric parameters and the constructed virtual model of the experimental bench flow part with the help of Creo Parametric 3.0 and ANSYS v. 16.2. Conducted CFD calculations and verification with experimental data. Identifies the steps for further experimental and virtual works.

Effectiveness of a patient education plan on knowledge of post-op venous thromboembolism survival skills.

PubMed

Green, Julie; Bernhofer, Esther I

2018-04-01

To investigate the effectiveness of a multimethod venous thromboembolism prevention patient education plan on participants' knowledge retention. A potential complication of surgery requiring general anaesthesia, worldwide, is the development of life-threatening venous thromboembolism. Patients need education on preventing, recognising and immediately responding to a suspected thromboembolism. Written instructional materials given to patients at discharge may be inadequate. A randomised controlled trial. Setting was multiple general surgery units at a large Midwestern United States academic medical centre. Sample included patients recovering from surgery with general anaesthesia: (N = 66), 68% female, 34 = experimental, 32 = usual care. Prior to discharge, participants in the experimental group were given a multimethod venous thromboembolism prevention education plan including a video, pamphlet and verbal instruction; control group received usual instructional pamphlet. Both groups received a knowledge test immediately before instruction. Two weeks following discharge, a phone call was made to participants to complete the postinstruction test. The relevant EQUATOR guideline, CONSORT checklist, was used for reporting this study. There were no statistically significant differences in age, gender, race, length of stay, surgery and history of venous thromboembolism among participants and group or test score results. No statistically significant difference in postinstruction score was found between groups. However, there was a trend in greater perception of importance in all groups and higher knowledge scores in the experimental group, with the percentage of participants in the experimental group answering all questions correctly rising from 38.2% correct to 73.5% correct. Teaching patients the importance of knowing venous thromboembolism signs and preventive/survival skills is potentially life-saving and nurses must know the importance of using the most effective methods for the learning needs of their patients. Further research including different education methods and testing is suggested. © 2018 John Wiley & Sons Ltd.

Nonlinear mathematical modeling and sensitivity analysis of hydraulic drive unit

NASA Astrophysics Data System (ADS)

Kong, Xiangdong; Yu, Bin; Quan, Lingxiao; Ba, Kaixian; Wu, Liujie

2015-09-01

The previous sensitivity analysis researches are not accurate enough and also have the limited reference value, because those mathematical models are relatively simple and the change of the load and the initial displacement changes of the piston are ignored, even experiment verification is not conducted. Therefore, in view of deficiencies above, a nonlinear mathematical model is established in this paper, including dynamic characteristics of servo valve, nonlinear characteristics of pressure-flow, initial displacement of servo cylinder piston and friction nonlinearity. The transfer function block diagram is built for the hydraulic drive unit closed loop position control, as well as the state equations. Through deriving the time-varying coefficient items matrix and time-varying free items matrix of sensitivity equations respectively, the expression of sensitivity equations based on the nonlinear mathematical model are obtained. According to structure parameters of hydraulic drive unit, working parameters, fluid transmission characteristics and measured friction-velocity curves, the simulation analysis of hydraulic drive unit is completed on the MATLAB/Simulink simulation platform with the displacement step 2 mm, 5 mm and 10 mm, respectively. The simulation results indicate that the developed nonlinear mathematical model is sufficient by comparing the characteristic curves of experimental step response and simulation step response under different constant load. Then, the sensitivity function time-history curves of seventeen parameters are obtained, basing on each state vector time-history curve of step response characteristic. The maximum value of displacement variation percentage and the sum of displacement variation absolute values in the sampling time are both taken as sensitivity indexes. The sensitivity indexes values above are calculated and shown visually in histograms under different working conditions, and change rules are analyzed. Then the sensitivity indexes values of four measurable parameters, such as supply pressure, proportional gain, initial position of servo cylinder piston and load force, are verified experimentally on test platform of hydraulic drive unit, and the experimental research shows that the sensitivity analysis results obtained through simulation are approximate to the test results. This research indicates each parameter sensitivity characteristics of hydraulic drive unit, the performance-affected main parameters and secondary parameters are got under different working conditions, which will provide the theoretical foundation for the control compensation and structure optimization of hydraulic drive unit.

Enhancing Productivity Through Feedback and Goal Setting. Final Report.

ERIC Educational Resources Information Center

Pritchard, Robert D.; And Others

A field test was conducted to research the effects of feedback and goal-setting techniques on increasing productivity. Subjects were regular employees of two autonomous clerical-type units in a credit card and payment processing center of a Southwestern oil company. The study desiqn had three phases--baseline period and two experimental conditions…

Performance Characteristics of Automotive Engines in the United States : First Series - Report No. 12 - 1975 Perkins Diesel 247 CID (4.0 Liters)

DOT National Transportation Integrated Search

1978-04-01

Experimental data were obtained in dynamometer tests of a 1975 Perkins 247-CID diesel engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine-operating modes. The objective of the p...

Performance Characteristics of Automotive Engines in the United States : Third Series - Report No. 11 - 1978 Oldsmobile Diesel, 350 CID (5.7 Liters)

DOT National Transportation Integrated Search

1979-02-01

Experimental data were obtained in dynamometer tests of a 1978 Oldsmobile Diesel, 350 CID (5.7 Liters) engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine-operating modes. The o...

Performance Characteristics of Automotive Engines in the United States : First Series - Report No. 14 - 1975 Mazda Rotary 70 CID (1.1 Liters), 4V

DOT National Transportation Integrated Search

1978-05-01

Experimental data were obtained in dynamometer tests of a 1975 Mazda 70 CID, 4V rotary engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine-operating modes. The objective of the ...

Problems of the Randomization Test for AB Designs

ERIC Educational Resources Information Center

Manolov, Rumen; Solanas, Antonio

2009-01-01

N = 1 designs imply repeated registrations of the behaviour of the same experimental unit and the measurements obtained are often few due to time limitations, while they are also likely to be sequentially dependent. The analytical techniques needed to enhance statistical and clinical decision making have to deal with these problems. Different…

Milling and Baking Test REsults for Eastern Soft Winter Wheats Harvested in 2010

USDA-ARS?s Scientific Manuscript database

The Soft Wheat Quality Council (SWQC) will provide an organization structure to evaluate the quality of soft wheat experimental lines and variety that may be grown in the traditional growing regions of the United States. The SWQC also will establish other activities as requested by the membership. ...

Performance Characteristics of Automotive Engines in the United States, Third Series - Report No. 6, 1978 Volkswagen Diesel, 90 CID (1.5 Liter), F.I.

DOT National Transportation Integrated Search

1979-02-01

Experimental data were obtained in dynamometer tests of a 1978 VW 90 CID engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine operating modes. The objective of the program is to ...

Performance Characteristics of Automotive Engines in the United States, Third Series - Report No. 7, 1978 Ford, 98 CID (1.6 Liters), 2V

DOT National Transportation Integrated Search

1979-02-01

Experimental data were obtained in dynamometer tests of a 1977 Chrysler 318 CID engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine operating modes. The objective of the program...

The Effects of Scenario Planning on Participant Decision-Making Style

ERIC Educational Resources Information Center

Chermack, Thomas J.; Nimon, Kim

2008-01-01

This research examines changes in decision-making styles as a result of participation in scenario planning. A quasi-experimental pretest-posttest design and several nonparametric tests were used to analyze data gathered from research participants in a technology firm in the Northeastern United States. Results show that participants tend to…

Test of localized nanagement for reducing deer browsing in forest regeneration areas

Treesearch

Brad F. Miller; Tyler A. Campbell; Ben R. Laseter; W.Mark Ford; Karl V. Miller

2010-01-01

White-tailed deer (Odocoileus virginianus) browsing in forest regeneration sites can affect current and future stand structure and species composition. Removal of deer social units (localized management) has been proposed as a strategy to alleviate deer overbrowsing in forest systems. We conducted an experimental localized removal in a high-density...

Collaborative Tool for Command and Control Team Effectiveness Studies: Experimental Test of Interventions to Improve Performance in Command and Control

DTIC Science & Technology

2008-11-01

weapons system in the United States Air Force (USAF) inventory (Garrity, Morley, Rodriguez , & Tossell, 2004). It is important for potential AOC operators...Research Division in Mesa , AZ. Additionally, cadets were able to participate in two conferences. Please see conference report at Attachment 3

International Space Station (ISS)

NASA Image and Video Library

1995-07-11

Artist's concept for Phase III of the International Space Station (ISS) as shown here in its completed and fully operational state with elements from the United States, Europe, Canada, Japan, and Russia. Sixteen countries are cooperating to provide a multidisciplinary laboratory, technology test bed, and observatory that will provide an unprecedented undertaking in scientific, technological, and international experimentation.

Performance Characteristics of Automotive Engines in the United States : First Series - Report No. 13 - 1975 American Motors 258 CID (4.2 Liters)

DOT National Transportation Integrated Search

1978-04-01

Experimental data were obtained in dynamometer tests of a 1975 AMC 258-CID production 1V engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine-operating modes. The objective of th...

Performance Characteristics of Automotive Engines in the United States, Third Series - Report No. 2, 1978 Pontiac, 301 CID (4.9 Liters), 2V

DOT National Transportation Integrated Search

1979-02-01

Experimental data were obtained in dynamometer tests of a 1978 Pontiac 301 CID engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine operating modes. The objective of the program ...

Performance Characteristics of Automotive Engines in the United States : First Series - Report No. 17 - 1975 Buick 455 CID (7.5 Liters), 4V

DOT National Transportation Integrated Search

1978-05-01

Experimental data were obtained in dynamometer tests of a 1975 Buick 455 CID, 4V engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine-operating modes. The objective of the progra...

Performance Characteristics of Automotive Engines in the United States : Second Series - Report No. 2 - 1976 Chevrolet 305 CID (5.0 Liters), 2V

DOT National Transportation Integrated Search

1978-04-01

Experimental data were obtained in dynamometer tests of a 1976 Chevrolet 305-CID V-8 engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine-operating modes. The objective of the pr...

Performance Characteristics of Automotive Engines in the United States : Third Series - Report No. 12 - 1978 Ford 140 CID (2.3 Liters), 2V

DOT National Transportation Integrated Search

1980-09-01

Experimental data were obtained in dynamometer tests of a 1978 Ford 140 CID engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine operating modes. The objective of the program is ...

Performance Characteristics of Automotive Engines in the United States : First Series - Report No. 16 - 1975 Volvo 121 CID (2.0 Liters), F.I.

DOT National Transportation Integrated Search

1978-05-01

Experimental data were obtained in dynamometer tests of a 1975 Volvo, 2.0 liter (121 CID) engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine-operating modes. The objective of t...

Performance Characteristics of Automotive Engines in the United States : Second Series - Report No. 5 - 1977 Ford 140 CID (2.3 Liters), 2V

DOT National Transportation Integrated Search

1978-05-01

Experimental data were obtained in dynamometer tests of a 1977 Ford 2.3 liter (140 CID) engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine-operating modes. The objective of the...

Performance Characteristics of Automotive Engines in the United States : Third Series - Report No. 1 - 1977 Volvo 130 CID (2.1 Liters), F.I.

DOT National Transportation Integrated Search

1978-05-01

Experimental data were obtained in dynamometer tests of a 1977 Volvo 130 CID engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine-operating modes. The objective of the program is...

Performance Characteristics of Automotive Engines in the United States : Second Series - Report No. 7 - 1977 Ford 171 CID (2.8 Liters), 2V

DOT National Transportation Integrated Search

1978-05-01

Experimental data were obtained in dynamometer tests of a 1977 Ford 171 CID engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine-operating modes. The objective of the program is ...

Performance Characteristics of Automotive Engines in the United States : First Series - Report No. 15 - 1975 Dodge Colt 98 CID (1.6 Liters), 2V

DOT National Transportation Integrated Search

1978-05-01

Experimental data were obtained in dynamometer tests of a 1975 Dodge Colt 1.6 liter (98 CID) engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine-operating modes. The objective o...

Performance Characteristics of Automotive Engines in the United States : Second Series - Report No. 3 - 1977 Chrysler 225 CID (3.7 Liters), 2V

DOT National Transportation Integrated Search

1978-04-01

Experimental data were obtained in dynamometer tests of a 1977 Chrysler 225-CID engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine-operating modes. The objective of the program...

Performance Characteristics of Automotive Engines in the United States, Third Series - Report No. 9, 1978 Ford, 300 CID (4.9 Liters), 1V

DOT National Transportation Integrated Search

1979-02-01

Experimental data were obtained in dynamometer tests of a 1978 Ford 140 300 CID engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine operating modes. The objective of the program...

Performance Characteristics of Automotive Engines in the United States : First Series - Report No. 18 - 1976 Ford 400 CID (6.6 Liters), 2V

DOT National Transportation Integrated Search

1978-05-01

Experimental data were obtained in dynamometer tests of a 1976 Ford 400 CID, 2V engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine-operating modes. The objective of the program...

Performance Characteristics of Automotive Engines in the United States : First Series - Report No. 19 - 1975 Ford Windsor 351 CID (5.7 Liters), 2V

DOT National Transportation Integrated Search

1978-05-01

Experimental data were obtained in dynamometer tests of a 1975 Ford 351 CID, 2V, Windsor engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine-operating modes. The objective of th...

Performance Characteristics of Automotive Engines in the United States, Third Series - Report No. 5, 1978 Chevrolet, 200 CID (3.3 Liter), 2V

DOT National Transportation Integrated Search

1979-02-01

Experimental data were obtained in dynamometer tests of a 1978 Chevrolet 200 CID engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine operating modes. The objective of the progra...

Performance Characteristics of Automotive Engines in the United States, Third Series, Report No. 8, 1978 Buick, 231 CID (3.8 Liters), 4V, Turbocharge

DOT National Transportation Integrated Search

1979-02-01

Experimental data were obtained in dynamometer tests of a 1978 Buick 231 CID turbocharged to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine operating modes. The objective of the prog...

Performance Characteristics of Automotive Engines in the United States, Third Series - Report No. 4, 1978 Pontiac, 151 CID (2.5 Liters), 2V

DOT National Transportation Integrated Search

1979-02-01

Experimental data were obtained in dynamometer tests of a 1978 Pontiac 151 CID engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine operating modes. The objective of the program ...

Performance Characteristics of Automotive Engines in the United States, Third Series, Report No. 3, 1978 AMC, 121 CID (2.0 Liters), 2V

DOT National Transportation Integrated Search

1979-02-01

Experimental data were obtained in dynamometer tests of a 1978 AMC 121 CID engine to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine operating modes. The objective of the program is t...

Performance Characteristics of Automotive Engines in the United States : Second Series - Report No. 6 - 1976 Nissan Diesel 198 CID (3.2 Liters), F.I.

DOT National Transportation Integrated Search

1978-05-01

Experimental data were obtained in dynamometer tests of a 1976 Nissan diesel engine, Model SD-33 CN6-33, to determine fuel consumption and emissions (hydrocarbon, carbon monoxide, oxides of nitrogen) at steady-state engine-operating modes. The object...

Experimental characterization of a solar cooker with thermal energy storage based on solar salt

NASA Astrophysics Data System (ADS)

Coccia, G.; Di Nicola, G.; Tomassetti, S.; Gabrielli, G.; Chieruzzi, M.; Pierantozzi, M.

2017-11-01

High temperature solar cooking allows to cook food fast and with good efficiency. An unavoidable drawback of this technology is that it requires nearly clear-sky conditions. In addition, evening cooking is difficult to be accomplished, particularly on the winter season during which solar radiation availability is limited to a few hours in the afternoon in most of countries. These restrictions could be overcome using a cooker thermal storage unit (TSU). In this work, a TSU based on solar salt was studied. The unit consists of two metal concentric cylindrical vessels, connected together to form a double-walled vessel. The volume between walls was filled with a certain amount of nitrate based phase change material (solar salt). In order to characterize the TSU, a test bench used to assess solar cooker performance was adopted. Experimental load tests with the TSU were carried out to evaluate the cooker performance. The obtained preliminary results show that the adoption of the solar salt TSU seems to allow both the opportunity of evening cooking and the possibility to better stabilize the cooker temperature when sky conditions are variable.

Accelerated/abbreviated test methods of the low-cost silicon solar array project. Study 4, task 3: Encapsulation

NASA Technical Reports Server (NTRS)

Kolyer, J. M.; Mann, N. R.

1977-01-01

Methods of accelerated and abbreviated testing were developed and applied to solar cell encapsulants. These encapsulants must provide protection for as long as 20 years outdoors at different locations within the United States. Consequently, encapsulants were exposed for increasing periods of time to the inherent climatic variables of temperature, humidity, and solar flux. Property changes in the encapsulants were observed. The goal was to predict long term behavior of encapsulants based upon experimental data obtained over relatively short test periods.

Simulation and Optimization of Vacuum Swing Adsorption Units for Spacesuit Carbon Dioxide and Humidity Control

NASA Technical Reports Server (NTRS)

Swickrath, Michael J.; Anderson, Molly; McMillin, Summer; Broerman, Craig

2011-01-01

Controlling carbon dioxide (CO2) and humidity levels in a spacesuit is critical to ensuring both the safety and comfort of an astronaut during extra-vehicular activity (EVA). Traditionally, this has been accomplished utilizing either non-regenerative lithium hydroxide (LiOH) or regenerative but heavy metal oxide (MetOx) canisters which pose a significant weight burden. Although such technology enables air revitalization, the volume requirements to store the waste canisters as well as the mass to transport multiple units become prohibitive as mission durations increase. Consequently, motivation exists toward developing a fully regenerative technology for spacesuit environmental control. The application of solid amine materials with vacuum swing adsorption technology has shown the capacity to control CO2 while concomitantly managing humidity levels through a fully regenerative cycle eliminating constraints imposed with the traditional technologies. Prototype air revitalization units employing this technology have been fabricated in both a rectangular and cylindrical geometry. Experimental results for these test articles have been collected and are described herein. In order to accelerate the developmental efforts, an axially-dispersed plug flow model with an accompanying energy balance has been established and correlated with the experimental data. The experimental and simulation results display good agreement for a variety of flow rates (110-170 ALM), replicated metabolic challenges (100-590 Watts), and atmosphere pressures under consideration for the spacesuit (248 and 760 mm Hg). The testing and model results lend insight into the operational capabilities of these devices as well as the influence the geometry of the device has on performance. In addition, variable metabolic profiles were imposed on the test articles in order to assess the ability of the technology to transition to new metabolic conditions. The advent of the model provides the capacity to apply computer-aided engineering practices to support the ongoing efforts to optimize and mature this technology for future application to space exploration.

A direct comparison of U.S. Environmental Protection Agency's method 304B and batch tests for determining activated-sludge biodegradation rate constants for volatile organic compounds

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

Cano, M.L.; Wilcox, M.E.; Compernolle, R. van

Biodegradation rate constants for volatile organic compounds (VOCs) in activated-sludge systems are needed to quantify emissions. One current US environmental Protection Agency method for determining a biodegradation rate constant is Method 304B. In this approach, a specific activated-sludge unit is simulated by a continuous biological treatment system with a sealed headspace. Batch experiments, however, can be alternatives to Method 304B. Two of these batch methods are the batch test that uses oxygen addition (BOX) and the serum bottle test (SBT). In this study, Method 304B was directly compared to BOX and SBT experiments. A pilot-scale laboratory reactor was constructed tomore » serve as the Method 304B unit. Biomass from the unit was also used to conduct BOX and modified SBT experiments (modification involved use of a sealed draft-tube reactor with a headspace recirculation pump instead of a serum bottle) for 1,2-dichloroethane, diisopropyl ether, methyl tertiary butyl ether, and toluene. Three experimental runs--each consisting of one Method 304B experiment, one BOX experiment, and one modified SBT experiment--were completed. The BOX and SBT data for each run were analyzed using a Monod model, and best-fit biodegradation kinetic parameters were determined for each experiment, including a first-order biodegradation rate constant (K{sub 1}). Experimental results suggest that for readily biodegradable VOCs the two batch techniques can provide improved means of determining biodegradation rate constants compared with Method 304B. In particular, these batch techniques avoid the Method 304B problem associated with steady-state effluent concentrations below analytical detection limits. However, experimental results also suggest that the two batch techniques should not be used to determine biodegradation rate constants for slowly degraded VOCs (i.e., K{sub 1} {lt} 0.1 L/g VSS-h).« less

Influence of computational fluid dynamics on experimental aerospace facilities: A fifteen year projection

NASA Technical Reports Server (NTRS)

1983-01-01

An assessment was made of the impact of developments in computational fluid dynamics (CFD) on the traditional role of aerospace ground test facilities over the next fifteen years. With improvements in CFD and more powerful scientific computers projected over this period it is expected to have the capability to compute the flow over a complete aircraft at a unit cost three orders of magnitude lower than presently possible. Over the same period improvements in ground test facilities will progress by application of computational techniques including CFD to data acquisition, facility operational efficiency, and simulation of the light envelope; however, no dramatic change in unit cost is expected as greater efficiency will be countered by higher energy and labor costs.

Quiet Clean Short-haul Experimental Engine (QCSEE) whirl test of cam/harmonic pitch change actuation system

NASA Technical Reports Server (NTRS)

1976-01-01

A variable pitch fan actuation system, which incorporates a remote nacelle mounted blade angle regulator, was tested. The regulator drives a rotating fan mounted mechanical actuator through a flexible shaft and differential gear train. The actuator incorporates a high ratio harmonic drive attached to a multitrack spherical cam which changes blade pitch through individual cam follower arms attached to each blade trunnion. Testing of the actuator on a whirl rig, is reported. Results of tests conducted to verify that the unit satisfied the design requirements and was structurally adequate for use in an engine test are presented.

Functionalization of SBA-15 mesoporous silica by Cu-phosphonate units: Probing of synthesis route

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

Laskowski, Lukasz, E-mail: lukasz.laskowski@kik.pcz.pl; Czestochowa University of Technology, Institute of Physics, Al. Armii Krajowej 19, 42-201 Czestochowa; Laskowska, Magdalena, E-mail: magdalena.laskowska@onet.pl

2014-12-15

Mesoporous silica SBA-15 containing propyl-copper phosphonate units was investigated. The structure of mesoporous samples was tested by N{sub 2} isothermal sorption (BET and BHJ analysis), TEM microscopy and X-Ray scattering. Quantitative analysis EDX has given information about proportions between component atoms in the sample. Quantitative elemental analysis has been carried out to support EDX. To examine bounding between copper atoms and phosphonic units the Raman spectroscopy was carried out. As a support of Raman scattering, the theoretical calculations were made based on density functional theory, with the B3LYP method. By comparison of the calculated vibrational spectra of the molecule withmore » experimental results, distribution of the active units inside silica matrix has been determined. - Graphical abstract: The present study is devoted to mesoporous silica SBA-15 containing propyl-copper phosphonate units. The species were investigated to confirm of synthesis procedure correctness by the micro-Raman technique combined with DFT numerical simulations. Complementary research was carried out to test the structure of mesoporous samples. - Highlights: • SBA-15 silica functionalized with propyl-copper phosphonate units was synthesized. • Synthesis efficiency probed by Raman study supported with DFT simulations. • Homogenous distribution of active units was proved. • Synthesis route enables precise control of distance between copper ions.« less

Development of a new photocatalytic oxidation air filter for aircraft cabin.

PubMed

Ginestet, A; Pugnet, D; Rowley, J; Bull, K; Yeomans, H

2005-10-01

A new photocatalytic oxidation air filter (PCO unit) has been designed for aircraft cabin applications. The PCO unit is designed as a regenerable VOC removal system in order to improve the quality of the recirculated air entering the aircraft cabin. The PCO was designed to be a modular unit, with four UV lamps sandwiched between two interchangeable titanium dioxide coated panels. Performances of the PCO unit has been measured in a single pass mode test rig in order to show the ability of the unit to decrease the amount of VOCs (toluene, ethanol, and acetone) entering it (VOCs are fed separately), and in a multipass mode test rig in order to measure the ability of the unit to clean the air of an experimental room polluted with the same VOCs (fed separately). Triangular cell panels have been chosen instead of the wire mesh panels because they have higher efficiency. The efficiency of the PCO unit depends on the type of VOCs that challenges it, toluene being the most difficult one to oxidise. The efficiency of the PCO unit decreases when the air flow rate increases. The multipass mode test results show that the VOCs are oxidized but additional testing time would be necessary in order to show if they can be fully oxidized. The intermediate reaction products are mainly acetaldehyde and formaldehyde whose amount depends on the challenge VOC. The intermediate reaction products are also oxidized and additional testing time would be necessary in order to show if they can be fully oxidized. The development of this new photocatalytic air filter is still going on. The VOC/odor removing adsorbers are available for only a small proportion of aircraft currently in service. The photocatalytic oxidation (PCO) technique has appeared to be a promising solution to odors problems met in aircraft. This article reports the test results of a new photocatalytic oxidation air filter (PCO unit) designed for aircraft cabin applications. The overall efficiency of the PCO unit is function of the compound (toluene, ethanol, and acetone) that challenges the unit and toluene appears to be the most difficult compound to oxidize. Test results have shown the influence of the design of the PCO unit, the air flow rate and the type of UV on the efficiency of the PCO unit. The results obtained in this study represent a first attempt on the way to design a filter for VOC removal in cabin aircraft applications. The PCO technique used by the tested prototype unit is able to partially oxidized the challenge VOCs but one has to be aware that some harmful intermediate reaction products (mainly formaldehyde and acetaldehyde) are produced during the oxidation process before being partially oxidized too.

Design and Theoretical Analysis of a Resonant Sensor for Liquid Density Measurement

PubMed Central

Zheng, Dezhi; Shi, Jiying; Fan, Shangchun

2012-01-01

In order to increase the accuracy of on-line liquid density measurements, a sensor equipped with a tuning fork as the resonant sensitive component is designed in this paper. It is a quasi-digital sensor with simple structure and high precision. The sensor is based on resonance theory and composed of a sensitive unit and a closed-loop control unit, where the sensitive unit consists of the actuator, the resonant tuning fork and the detector and the closed-loop control unit comprises precondition circuit, digital signal processing and control unit, analog-to-digital converter and digital-to-analog converter. An approximate parameters model of the tuning fork is established and the impact of liquid density, position of the tuning fork, temperature and structural parameters on the natural frequency of the tuning fork are also analyzed. On this basis, a tuning fork liquid density measurement sensor is developed. In addition, experimental testing on the sensor has been carried out on standard calibration facilities under constant 20 °C, and the sensor coefficients are calibrated. The experimental results show that the repeatability error is about 0.03% and the accuracy is about 0.4 kg/m3. The results also confirm that the method to increase the accuracy of liquid density measurement is feasible. PMID:22969378

Design and theoretical analysis of a resonant sensor for liquid density measurement.

PubMed

Zheng, Dezhi; Shi, Jiying; Fan, Shangchun

2012-01-01

In order to increase the accuracy of on-line liquid density measurements, a sensor equipped with a tuning fork as the resonant sensitive component is designed in this paper. It is a quasi-digital sensor with simple structure and high precision. The sensor is based on resonance theory and composed of a sensitive unit and a closed-loop control unit, where the sensitive unit consists of the actuator, the resonant tuning fork and the detector and the closed-loop control unit comprises precondition circuit, digital signal processing and control unit, analog-to-digital converter and digital-to-analog converter. An approximate parameters model of the tuning fork is established and the impact of liquid density, position of the tuning fork, temperature and structural parameters on the natural frequency of the tuning fork are also analyzed. On this basis, a tuning fork liquid density measurement sensor is developed. In addition, experimental testing on the sensor has been carried out on standard calibration facilities under constant 20 °C, and the sensor coefficients are calibrated. The experimental results show that the repeatability error is about 0.03% and the accuracy is about 0.4 kg/m(3). The results also confirm that the method to increase the accuracy of liquid density measurement is feasible.

The effect of reflective writing interventions on the critical thinking skills and dispositions of baccalaureate nursing students.

PubMed

Naber, Jessica; Wyatt, Tami H

2014-01-01

The importance of critical thinking is well-documented by the American Association of Colleges of Nursing and the National League for Nursing. Reflective writing is often used to increase understanding and analytical ability. The lack of empirical evidence about the effect of reflective writing interventions on critical thinking supports the examination of this concept. Study objectives were: This study used an experimental, pretest-posttest design. The setting was two schools of nursing at universities in the southern United States. The convenience sample included 70 fourth-semester students in baccalaureate nursing programs. Randomly assigned control and experimental groups completed the California Critical Thinking Skills Test (CCTST) and the California Critical Thinking Dispositions Inventory Test (CCTDI). The experimental group completed six reflective writing assignments. Both groups completed the two tests again. Results showed that the experimental group had a significant increase (p=0.03) on the truthseeking subscale of the CCTDI when compared to the control group. The experimental group's scores increased on four CCTST subscales and were higher than the control group's on three CCTST subscales. The results of this study make it imperative for nursing schools to consider including reflective writing-especially assignments based on Paul's (1993) model-in nursing courses. If future studies, testing over longer periods of time, show significant increases in critical thinking, those interventions could be incorporated into nursing curriculum and change the way nurse educators evaluate students. Copyright © 2013 Elsevier Ltd. All rights reserved.

Experimental Interactions of Components of Hemodialysis Units with Human Blood

PubMed Central

Zucker, W. H.; Shinoda, B. A.; Mason, R. G.

1974-01-01

An in vitro model test system for estimation of the blood compatibility of hemodialysis membranes and tubing is described. The model test system consists of a modified hemodialysis unit and blood pump through which fresh citrated human blood is circulated. The effects of the use of different pump and tubing types upon hematologic and blood coagulation parameters are described. Preexposure of test surfaces to albumin appeared to enhance blood compatibility characteristics of the model test system, whereas preexposure to a high density lipoprotein preparation or a proteinpolysaccharide preparation was without appreciable benefit. Use of blood from subjects receiving aspirin resulted in enhanced blood compatibility in the test system as did use of heparin. Use of Warfarin or dextran did not appear to enhance blood compatibility of test surfaces under the conditions of this test system. Dialysis membranes and tubing which formed parts of the test system were examined by scanning and transmission electron microscopy in control tests and in tests for effects of proteins and antithrombotic agents. ImagesFig 5Fig 6Fig 7Fig 8Fig 9Fig 10Fig 11Fig 12Fig 13Fig 14Fig 1Fig 2Fig 3Fig 4 PMID:4825611

Mixing soil samples across experimental units ignores uncertainty and generates falsely precise estimates of soil biota effects on plants

USDA-ARS?s Scientific Manuscript database

A number of recent soil biota studies have deviated from the standard experimental approach of generating a distinct data value for each experimental unit (e.g. Yang et al., 2013; Gundale et al., 2014). Instead, these studies have mixed together soils from multiple experimental units (i.e. sites wi...

Light-Emitting Diodes: A Hidden Treasure

ERIC Educational Resources Information Center

Planinšic, Gorazd; Etkina, Eugenia

2014-01-01

LEDs, or light-emitting diodes, are cheap, easy to purchase, and thus commonly used in physics instruction as indicators of electric current or as sources of light (Fig. 1). In our opinion LEDs represent a unique piece of equipment that can be used to collect experimental evidence, and construct and test new ideas in almost every unit of a general…

GROUP COUNSELING-PLUS--INCREASING SCHOOL SUCCESS OF JUNIOR COLLEGE STUDENTS.

ERIC Educational Resources Information Center

DESSENT, SHIRLEY C.

TO TEST THE HYPOTHESIS THAT STUDENTS ON ACADEMIC PROBATION WHO RECEIVED SUPPORT AND INSIGHT FROM A GROUP WOULD OBTAIN HIGHER GRADE POINT AVERAGES THAN THOSE WITHOUT SUCH AN EXPERIENCE, THE RECORDS OF AN EXPERIMENTAL GROUP OF 30 PROBATIONARY STUDENTS WERE MATCHED ON THE BASIS OF AGE, SEX, AND NUMBER OF UNITS TAKEN, MARITAL STATUS OF PARENTS,…

76 FR 30341 - Town of Edgartown; Notice of Preliminary Permit Application Accepted for Filing and Soliciting...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-25

...), filed an application for a successive preliminary permit, pursuant to section 4(f) of the Federal Power Act (FPA), proposing to study the feasibility of the Muskeget Channel Tidal Energy Project to be..., and one experimental turbine unit that would be used to test various open- bladed and helical tidal...

Advanced Communications Technology Satellite (ACTS). Phase 1: Industrial/academic experimenters

NASA Technical Reports Server (NTRS)

Maisel, James E.; Nowlin, Robert W.

1992-01-01

This report presents the work done at Arizona State University under the ACTS Experimenters Program. The main thrust of the Program was to develop experiments to test, evaluate, and prove the commercial worthiness of the ACTS satellite which is scheduled for launch in 1993. To accomplish this goal, meetings were held with various governmental, industrial, and academic units to discuss the ACTS satellite and its technology and possible experiments that would generate industrial interest and support for ASU's efforts. Several local industries generated several experiments of their own. The investigators submitted several experiments of educational, medical, commercial, and technical value and interest. The disposition of these experimental proposals is discussed in this report.

Design, Fabrication and Testing of Two Different Laboratory Prototypes of CSI-based Induction Heating Units

NASA Astrophysics Data System (ADS)

Roy, M.; Sengupta, M.

2012-09-01

Induction heating is a non-contact heating process which became popular due to its energy efficiency. Current source inverter (CSI) based induction heating units are commonly used in the industry. Most of these CSIs are thyristor based, since thyristors of higher ratings are easily available. These being load commutated apparatus a start-up circuit is needed to initiate commutation. In this paper the design and fabrication of two laboratory prototypes have been presented. The first one, a SCR-based CSI fed controlled induction heating unit (IHU), has been tested with two different types of start-up procedures. Thereafter the fabrication and performance of another IGBT-based CSI is compared with the thyristor-based CSI for a 2 kW, 10 kHz application. These two types of CSIs are fully fabricated in laboratory along with the IHU. Performance analysis and simulation of two different CSIs has been done by using SequelGUI2. The triggering pulses for the inverter devices (for both CSI devices as well as auxilliary thyristor of start-up circuit) have been generated and closed-loop control has been done in FPGA platform built around an Altera make cyclone EPIC12Q240C processor which can be programmed using Quartus II software. Close agreement between simulated and experimental results highlight the accuracy of the experimental work.

Experimental Investigations And Numerical Modelling of 210CR12 Steel in Semi-Solid State

NASA Astrophysics Data System (ADS)

Macioł, Piotr; Zalecki, Władysław; Kuziak, Roman; Jakubowicz, Aleksandra; Weglarczyk, Stanisław

2011-05-01

Experimental investigation, including hot compression and simple closed die filling was performed. Temperature range of tests was between 1225 °C and 1320 °C. Temperature selection was adequate with liquid fraction between 20 and 60%, which is typical for thixoforming processes. In the die filling test, steel dies with ceramic layer was used (highly refractory air-setting mortar JM 3300 manufactured by Thermal Ceramics). Experiments were carried out on the Gleeble 3800 physical simulator with MCU unit. In the paper, methodology of experimental investigation is described. Dependency of forming forces on temperature and forming velocities is analysed. Obtained results are discussed. The second part of the paper concerns numerical modelling of semi-solid forming. Numerical models for both sets of test were developed. Structural and Computational Fluid Dynamics models are compared. Initial works in microstructural modelling of 210CR12 steel behaviour are described. Lattice Boltzman Method model for thixotropic flows is introduced. Microscale and macroscale models were integrated into multiscale simulation of semi-solid forming. Some fundamental issues related to multiscale modelling of thixoforming are discussed.

Experimental Techniques for Evaluating the Effects of Aging on Impact and High Strain Rate Properties of Triaxial Braided Composite Materials

NASA Technical Reports Server (NTRS)

Pereira, J. Michael; Roberts, Gary D.; Ruggeri, Charles R.; Gilat, Amos; Matrka, Thomas

2010-01-01

An experimental program is underway to measure the impact and high strain rate properties of triaxial braided composite materials and to quantify any degradation in properties as a result of thermal and hygroscopic aging typically encountered during service. Impact tests are being conducted on flat panels using a projectile designed to induce high rate deformation similar to that experienced in a jet engine fan case during a fan blade-out event. The tests are being conducted on as-fabricated panels and panels subjected to various numbers of aging cycles. High strain rate properties are being measured using a unique Hopkinson bar apparatus that has a larger diameter than conventional Hopkinson bars. This larger diameter is needed to measure representative material properties because of the large unit cell size of the materials examined in this work. In this paper the experimental techniques used for impact and high strain rate testing are described and some preliminary results are presented for both as-fabricated and aged composites.

Testing of the 15-inch air-sparged hydrocyclone for fine coal flotation at the Homer City preparation plant

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

Miller, J.D.; Yi, Y.; Gopalakrishnan, S.

1993-12-31

Previous plant testing had been limited to the processing of minus 100 mesh classifier overflow (Upper Freeport Coal {approximately} 20% ash) with the 6-inch air-sparged hydrocyclone (ASH-6C) as reported at Coal Prep 92. The ASH-6C unit was found to provide separation efficiencies equivalent, or superior, to separations with the ASH-2C system. During the summer of 1992 the construction of the first 15-inch air-sparged hydrocyclone prototype was completed by the Advanced Processing Technologies, Inc. Installation at the Homer City Coal Preparation Plant was accomplished and testing began in October 1992. The ASH-15C unit can operate at a flowrate as high asmore » 1,000 gpm. Experimental results are reported with respect to capacity, combustible recovery and clean coal quality.« less

Experimental research on a modular miniaturization nanoindentation device

NASA Astrophysics Data System (ADS)

Huang, Hu; Zhao, Hongwei; Mi, Jie; Yang, Jie; Wan, Shunguang; Yang, Zhaojun; Yan, Jiwang; Ma, Zhichao; Geng, Chunyang

2011-09-01

Nanoindentation technology is developing toward the in situ test which requires miniaturization of indentation instruments. This paper presents a miniaturization nanoindentation device based on the modular idea. It mainly consists of macro-adjusting mechanism, x-y precise positioning platform, z axis precise driving unit, and the load-depth measuring unit. The device can be assembled with different forms and has minimum dimensions of 200 mm × 135 mm × 200 mm. The load resolution is about 0.1 mN and the displacement resolution is about 10 nm. A new calibration method named the reference-mapping method is proposed to calibrate the developed device. Output performance tests and indentation experiments indicate the feasibility of the developed device and calibration method. This paper gives an example that combining piezoelectric actuators with flexure hinge to realize nanoindentation tests. Integrating a smaller displacement sensor, a more compact nanoindentation device can be designed in the future.

Accelerated Leach Testing of GLASS: ALTGLASS Version 3.0

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

Trivelpiece, Cory L.; Jantzen, Carol M.; Crawford, Charles L.

The Accelerated Leach Testing of GLASS (ALTGLASS) database is a collection of data from short- and long-term product consistency tests (PCT, ASTM C1285 A and B) on high level waste (HLW) as well as low activity waste (LAW) glasses. The database provides both U.S. and international researchers with an archive of experimental data for the purpose of studying, modeling, or validating existing models of nuclear waste glass corrosion. The ALTGLASS database is maintained and updated by researchers at the Savannah River National Laboratory (SRNL). This newest version, ALTGLASS Version 3.0, has been updated with an additional 503 rows of datamore » representing PCT results from corrosion experiments conducted in the United States by the Savannah River National Laboratory, Pacific Northwest National Laboratory, Argonne National Laboratory, and the Vitreous State Laboratory (SRNL, PNNL, ANL, VSL, respectively) as well as the National Nuclear Laboratory (NNL) in the United Kingdom.« less

Evaluation of BAUER UTILUS 10 and TRIPLEX Purification Systems

DTIC Science & Technology

1993-08-01

of the test was to: A. Determine if the compressor and Purification System provides compressed air at the required pressures, flow rates, quality and...optimum filtering, moisture separation, third stage piston ring expansion/cylinder sealing and prevents compressed air return from the storage flasks to the...551 COMPRESSED AIR PLANTS AND SYSTEMS S9086-SY-STM-O0O PARA 551-4.2.2.1. 6. Navy Experimental Diving Unit Test Plan Number 93-01, Jan 93. 7. NAVSEAINST

Clinical trials transparency and the Trial and Experimental Studies Transparency (TEST) act.

PubMed

Logvinov, Ilana

2014-03-01

Clinical trial research is the cornerstone for successful advancement of medicine that provides hope for millions of people in the future. Full transparency in clinical trials may allow independent investigators to evaluate study designs, perform additional analysis of data, and potentially eliminate duplicate studies. Current regulatory system and publishers rely on investigators and pharmaceutical industries for complete and accurate reporting of results from completed clinical trials. Legislation seems to be the only way to enforce mandatory disclosure of results. The Trial and Experimental Studies Transparency (TEST) Act of 2012 was introduced to the legislators in the United States to promote greater transparency in research industry. Public safety and advancement of science are the driving forces for the proposed policy change. The TEST Act may benefit the society and researchers; however, there are major concerns with participants' privacy and intellectual property protection. Copyright © 2014 Elsevier Inc. All rights reserved.

An experimental determination of the drag coefficient of a Mens 8+ racing shell.

PubMed

Buckmann, James G; Harris, Samuel D

2014-01-01

This study centered around an experimental analysis of a Mens Lightweight Eight racing shell and, specifically, determining an approximation for the drag coefficient. A testing procedure was employed that used a Global Positioning System (GPS) unit in order to determine the acceleration and drag force on the shell, and through calculations yield a drag coefficient. The testing was run over several days in numerous conditions, and a 95% confidence interval was established to capture the results. The results obtained, over these varying trials, maintained a successful level of consistency. The significance of this study transcends the determination an approximation for the drag coefficient of the racing shell; it defined a successful means of quantifying performance of the shell itself. The testing procedures outlined in the study represent a uniform means of evaluating the factors that influence drag on the shell, and thus influence speed.

An Electromagnetic/Capacitive Composite Sensor for Testing of Thermal Barrier Coatings

PubMed Central

Ren, Yuan; Pan, Mengchun; Chen, Dixiang; Tian, Wugang

2018-01-01

Thermal barrier coatings (TBCs) can significantly reduce the operating temperature of the aeroengine turbine blade substrate, and their testing technology is very urgently demanded. Due to their complex multi-layer structure, it is hard to evaluate TBCs with a single function sensor. In this paper, an electromagnetic/capacitive composite sensor is proposed for the testing of thermal barrier coatings. The dielectric material is tested with planar capacitor, and the metallic material is tested with electromagnetic coils. Then, the comprehensive test and evaluation of thermal barrier coating system can be realized. The sensor is optimized by means of theoretical and simulation analysis, and the interaction between the planar capacitor and the electromagnetic coil is studied. The experimental system is built based on an impedance analyser and multiplex unit to evaluate the performance of the composite sensor. The transimpedances and capacitances are measured under different coating parameters, such as thickness and permittivity of top coating as well as bond layer conductivity. The experimental results agree with the simulation analysis, and the feasibility of the sensor is proved. PMID:29783746

Teaching About Genetics and Sickle Cell Disease In Fifth Grade.

PubMed

Day, Lucille Lang; Murray, Eileen; Treadwell, Marsha J; Lubin, Bertram H

2015-02-01

We are grateful to Laura McVittie Gray for her work on the development of the student activities described in this article. This work was made possible by a Science Education Partnership Award (SEPA), Grant Number R25RR020449, from the National Center for Research Resources (NCRR), a component of the National Institutes of Health (NIH). Additional support for this SEPA-funded project was provided by Grant Number UL1RR024131-01 from NCRR. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of NCRR or NIH. A 5-lesson, 5th-grade instructional unit, "Genetics and Sickle Cell Disease," was developed and tested as part of a 40-lesson curriculum entitled SEEK (Science Exploration, Excitement, and Knowledge): A Curriculum in Health and Biomedical Science for Diverse 4th and 5th Grade Students. The genetics lessons include hands-on activities (e.g., DNA extraction from cheek cells), a simulated plant genetics experiment, and a classroom visit by a person with sickle cell disease, as well as by a health care practitioner who works with sickle cell patients or a scientist specializing in genetics. The unit was tested with 82 5th-grade students at public elementary schools in Oakland, CA; 96% were racial and ethnic minorities. The comparison group consisted of 84 5th-grade Oakland students racially/ ethnically, academically, and socio-economically matched to those in the experimental group. Both groups completed a 20-question, multiple-choice pre/posttest covering science concepts, scientific process, lifestyle choices, and careers. The experimental group showed significant improvement on 13 of 20 questions (P<.05, t-tests) and on the test as a whole, whereas the comparison group did not show significant improvement either on any of the questions or on the test as a whole. The experimental group improved on 10 concept questions, 2 scientific process questions, and 1 lifestyle question. Teachers rated the educational value of the unit as 9.5 on a scale from 1 (low) to 10 (high). These results show that genetics and sickle cell disease can be taught successfully in 5th grade, although they are not typically covered at this level. © 2015 National Medical Association. Published by Elsevier Inc. All rights reserved.

The effectiveness of interventions to meet family needs of critically ill patients in an adult intensive care unit: a systematic review.

PubMed

Kynoch, Kate; Chang, Anne M; Coyer, Fiona

Background Attending to the needs of family members of critically ill patients is an important and necessary step in providing appropriate care for both the patient and the family. An initial search of the Cochrane and Joanna Briggs Institute Libraries did not reveal any published systematic reviews recommending effective interventions for addressing family needs of critically ill patients in an acute intensive care unit.Objectives This systematic review aims to establish best practice in addressing the needs of family members with a relative admitted to an adult critical care unit.Search strategy An extensive search of the major databases was conducted. Databases searched included: MEDLINE, CINAHL, psycINFO, Health source, Web of science, EMBASE, the Cochrane library and Database of abstracts of reviews of effects (DARE) as well as Pubmed. The search included published and unpublished studies and papers in English from 1980-2010.Selection criteria This review considered any randomised controlled trials that evaluated the effectiveness of interventions in addressing family needs of critically ill patients in an adult intensive care unit. In the absence of randomised controlled trials, other research designs such as quasi-experimental as well as before and after studies were considered for inclusion in the narrative summary to enable the identification of current approaches and possible future strategies for addressing family needs of critically ill patients.Assessment of quality Each included study was assessed by two independent reviewers using the appropriate appraisal checklist developed by the Joanna Briggs Institute.Data collection and analysis Data was extracted from the papers included in this review using standardised data extraction tools from the Joanna Briggs Institute Meta Analysis of Statistics Assessment and Review Instrument package. The studies included in this review were not suitable for meta-analysis and therefore the results are presented in narrative form.Results Fourteen studies and one dissertation met the inclusion criteria and were included in the review. There were 12 quasi-experimental studies identified including 8 two or three group, pre-test/post-test studies; 1 one-way between subjects design; 1 interrupted time series and 1 two-group comparative design study. The dissertation was a quasi-experimental three group pre-test/post-test design. There were 3 prospective randomised trials included. The evidence identified includes: the use of support groups for family members of patients admitted to an intensive care unit, structured communication and/or education programs for family members, the use of leaflets or brochures to meet family information needs and open or more flexible visiting hours.Conclusion/Recommendations This review makes several recommendations for clinical practice to address family needs of patients admitted to a critical care unit, however this review highlights the need for significant further research in this area. Future intervention studies focusing on family needs could include: the use of technology such as DVD's and SMS for informing families and interventions specifically designed to improve family comfort.

A study to compare traditional and constructivism-based instruction of a high school biology unit on biosystematics

NASA Astrophysics Data System (ADS)

Saigo, Barbara Woodworth

The researcher collaborated with four high school biology teachers who had been involved for 2-1/2 years in a constructivism-based professional development experience that emphasized teaching for conceptual change and using classroom-based inquiry as a basis for making instructional decisions. The researcher and teachers designed a five-day instructional unit on biosystematics using two contrasting approaches, comprising the treatment variable. The "traditional" unit emphasized lecture, written materials, and some laboratory activities. The "constructivist" unit emphasized a specific, inquiry-based, conceptual change strategy and collaborative learning. The study used a quasi-experimental, factorial design to explore impact of instructional approach (the treatment variable) on student performance (the dependent variable) on repeated measures (three) of a biology concept test. Additional independent variables considered were gender, cumulative GPA, and the section in which students were enrolled. Scores on the biology concept test were compiled for the 3 constructivist sections (N = 44) and the 3 traditional sections (N = 42). Analysis of Covariance (ANCOVA) was applied. The main findings in regard to the primary research question were that instructional approach did not have a significant relationship to immediate post test scores or gain, but that one month after instruction students in the constructivist group demonstrated less loss of gain than those in the traditional group; i.e., their longer-term retention was greater. Also, GPA*instructional approach effects were detected for post-post-test gain. GPA and gender were significantly associated with pre-test, post-test, and post-post scores; however, in terms of change (gain) from pre-test to post-test and pre-test to post-post-test, GPA and gender were not significant effects. Section was a significant effect for all three tests, in terms of both score and gain. Gender*section effects were detected for post-test gain and post-post-test scores.

SPHERES Facility

NASA Technical Reports Server (NTRS)

Martinez, Andres; Benavides, Jose Victor; Ormsby, Steve L.; GuarnerosLuna, Ali

2014-01-01

Synchronized Position Hold, Engage, Reorient, Experimental Satellites (SPHERES) are bowling-ball sized satellites that provide a test bed for development and research into multi-body formation flying, multi-spacecraft control algorithms, and free-flying physical and material science investigations. Up to three self-contained free-flying satellites can fly within the cabin of the International Space Station (ISS), performing flight formations, testing of control algorithms or as a platform for investigations requiring this unique free-flying test environment. Each satellite is a self-contained unit with power, propulsion, computers, navigation equipment, and provides physical and electrical connections (via standardized expansion ports) for Principal Investigator (PI) provided hardware and sensors.

Computer experimental analysis of the CHP performance of a 100 kW e SOFC Field Unit by a factorial design

NASA Astrophysics Data System (ADS)

Calì, M.; Santarelli, M. G. L.; Leone, P.

Gas Turbine Technologies (GTT) and Politecnico di Torino, both located in Torino (Italy), have been involved in the design and installation of a SOFC laboratory in order to analyse the operation, in cogenerative configuration, of the CHP 100 kW e SOFC Field Unit, built by Siemens-Westinghouse Power Corporation (SWPC), which is at present (May 2005) starting its operation and which will supply electric and thermal power to the GTT factory. In order to take the better advantage from the analysis of the on-site operation, and especially to correctly design the scheduled experimental tests on the system, we developed a mathematical model and run a simulated experimental campaign, applying a rigorous statistical approach to the analysis of the results. The aim of this work is the computer experimental analysis, through a statistical methodology (2 k factorial experiments), of the CHP 100 performance. First, the mathematical model has been calibrated with the results acquired during the first CHP100 demonstration at EDB/ELSAM in Westerwoort. After, the simulated tests have been performed in the form of computer experimental session, and the measurement uncertainties have been simulated with perturbation imposed to the model independent variables. The statistical methodology used for the computer experimental analysis is the factorial design (Yates' Technique): using the ANOVA technique the effect of the main independent variables (air utilization factor U ox, fuel utilization factor U F, internal fuel and air preheating and anodic recycling flow rate) has been investigated in a rigorous manner. Analysis accounts for the effects of parameters on stack electric power, thermal recovered power, single cell voltage, cell operative temperature, consumed fuel flow and steam to carbon ratio. Each main effect and interaction effect of parameters is shown with particular attention on generated electric power and stack heat recovered.

A Compact Energy Harvesting System for Outdoor Wireless Sensor Nodes Based on a Low-Cost In Situ Photovoltaic Panel Characterization-Modelling Unit.

PubMed

Antolín, Diego; Medrano, Nicolás; Calvo, Belén; Martínez, Pedro A

2017-08-04

This paper presents a low-cost high-efficiency solar energy harvesting system to power outdoor wireless sensor nodes. It is based on a Voltage Open Circuit (VOC) algorithm that estimates the open-circuit voltage by means of a multilayer perceptron neural network model trained using local experimental characterization data, which are acquired through a novel low cost characterization system incorporated into the deployed node. Both units-characterization and modelling-are controlled by the same low-cost microcontroller, providing a complete solution which can be understood as a virtual pilot cell, with identical characteristics to those of the specific small solar cell installed on the sensor node, that besides allows an easy adaptation to changes in the actual environmental conditions, panel aging, etc. Experimental comparison to a classical pilot panel based VOC algorithm show better efficiency under the same tested conditions.

Effect of Cooling Units on the Performance of an Automotive Exhaust-Based Thermoelectric Generator

NASA Astrophysics Data System (ADS)

Su, C. Q.; Zhu, D. C.; Deng, Y. D.; Wang, Y. P.; Liu, X.

2017-05-01

Currently, automotive exhaust-based thermoelectric generators (AETEGs) are a hot topic in energy recovery. In order to investigate the influence of coolant flow rate, coolant flow direction and cooling unit arrangement in the AETEG, a thermoelectric generator (TEG) model and a related test bench are constructed. Water cooling is adopted in this study. Due to the non-uniformity of the surface temperature of the heat source, the coolant flow direction would affect the output performance of the TEG. Changing the volumetric flow rate of coolant can increase the output power of multi-modules connected in series or/and parallel as it can improve the temperature uniformity of the cooling unit. Since the temperature uniformity of the cooling unit has a strong influence on the output power, two cooling units are connected in series or parallel to research the effect of cooling unit arrangements on the maximum output power of the TEG. Experimental and theoretical analyses reveal that the net output power is generally higher with cooling units connected in parallel than cooling units connected in series in the cooling system with two cooling units.

Supporting High School Student Accomplishment of Biology Content Using Interactive Computer-Based Curricular Case Studies

NASA Astrophysics Data System (ADS)

Oliver, Joseph Steve; Hodges, Georgia W.; Moore, James N.; Cohen, Allan; Jang, Yoonsun; Brown, Scott A.; Kwon, Kyung A.; Jeong, Sophia; Raven, Sara P.; Jurkiewicz, Melissa; Robertson, Tom P.

2017-11-01

Research into the efficacy of modules featuring dynamic visualizations, case studies, and interactive learning environments is reported here. This quasi-experimental 2-year study examined the implementation of three interactive computer-based instructional modules within a curricular unit covering cellular biology concepts in an introductory high school biology course. The modules featured dynamic visualizations and focused on three processes that underlie much of cellular biology: diffusion, osmosis, and filtration. Pre-tests and post-tests were used to assess knowledge growth across the unit. A mixture Rasch model analysis of the post-test data revealed two groups of students. In both years of the study, a large proportion of the students were classified as low-achieving based on their pre-test scores. The use of the modules in the Cell Unit in year 2 was associated with a much larger proportion of the students having transitioned to the high-achieving group than in year 1. In year 2, the same teachers taught the same concepts as year 1 but incorporated the interactive computer-based modules into the cell biology unit of the curriculum. In year 2, 67% of students initially classified as low-achieving were classified as high-achieving at the end of the unit. Examination of responses to assessments embedded within the modules as well as post-test items linked transition to the high-achieving group with correct responses to items that both referenced the visualization and the contextualization of that visualization within the module. This study points to the importance of dynamic visualization within contextualized case studies as a means to support student knowledge acquisition in biology.

The Effect of Environmental Field Trips on Student Learning in Middle School

ERIC Educational Resources Information Center

Legutko, Robert S.

2005-01-01

The effect of an environmental field trip on student learning in one middle school in the mid-Atlantic region of the United States was examined. An experimental one-group pretest-posttest group design was implemented on a sample of 579 students which comprised 12 groups. Although a t-test for dependent samples indicated that less than half of the…

Compaction Characteristics of Earth-Rock Mixtures. Report 1. Vicksburg Silty Clay and Degray Dam Clayey Sandy Gravel

DTIC Science & Technology

1973-05-01

dry density of total sample Yf = dry unit weight of finer fraction G = bulk specific gravity of coarser fraction (based on ovendry weightq). Same as G...ttl~o o 40 oe o Fig. ii. Theoretical and experimental densities of eclayey sandy gravel (GC) DeGray meterial expressions require tests performed on

A New Experimental System Design Related to the Plasma State

ERIC Educational Resources Information Center

Korkmaz, S. D.

2015-01-01

The plasma state is included in the unit on matter and its properties in the 9th grade Physics course secondary school curriculum prepared by the Ministry of National Education of Turkey. Any tools and equipment required by tests to be conducted in the scope of the Physics course curriculum are in general easily accessible. However, in cases in…

A Multilevel Analysis of a Guided Inquiry Curriculum Unit on Motion and Force for a Diverse Student Population in "Ability-Grouped" Classrooms

ERIC Educational Resources Information Center

Rethinam, Vasuki; Lynch, Sharon J.

2011-01-01

This study is an evaluation of "Exploring Motion and Forces: Speed, Acceleration, and Friction" ("M&F") developed by ARIES of the Harvard-Smithsonian Center for Astrophysics (2001). Although "M&F" has been used in many schools and field-tested, it has never been evaluated in rigorous experimental or…

A trial of direct control of pine engraver beetles on a small logging unit

Treesearch

W. L. Jackson

1960-01-01

Laboratory tests and small-scale field trials have shown the insecticide lindane to be highly toxic to pine engraver beetles. On the basis of that information, the insecticide was applied to fresh logging slash heavily infested with pine engraver beetles at Challenge Experimental Forest in 1959. Costs were reasonable and no insurmountable problems were encountered....

Do Mathematics and Reading Competencies Integrated into Career and Technical Education Courses Improve High School Student State Assessment Scores?

ERIC Educational Resources Information Center

Pierce, Kristin B.; Hernandez, Victor M.

2015-01-01

A quasi experimental study tested a contextual teaching and learning model for integrating reading and mathematics competencies through 13 introductory career and technical education (CTE) courses. The treatment group consisted of students in the 13 introductory courses taught by the CTE teachers who designed the units and the control group…

Guiding the Design of Lessons by Using the MAPLET Framework: Matching Aims, Processes, Learner Expertise and Technologies

ERIC Educational Resources Information Center

Ifenthaler, Dirk; Gosper, Maree

2014-01-01

This paper introduces the MAPLET framework that was developed to map and link teaching aims, learning processes, learner expertise and technologies. An experimental study with 65 participants is reported to test the effectiveness of the framework as a guide to the design of lessons embedded within larger units of study. The findings indicate the…

Kinetics and advanced digester design for anaerobic digestion of water hyacinth and primary sludge

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

Chynoweth, D.P.; Dolenc, D.A.; Ghosh, S.

1982-01-01

A research program centered around a facility located at Walt Disney World (WDW) is in progress to evaluate the use of water hyacinth (WH) for secondary and tertiary wastewater treatment, to optimize growth of WH under these conditions, and to convert the resultant primary sludge (PS) and WH to methane via anaerobic digestion. This article describes the status of the biogasification component of this program, which includes baseline and advanced digestion experiments with individual feeds and blends and the design of an experimental test unit (ETU) to be installed at WDW. Experiments with several blends demonstrated that methane yields canmore » be predicted from the fractional content and methane yield of each component. The process was found to adhere to the Monod kinetic model for microbial growth, and associated kinetic parameters were developed for various feed combinations. A novel upflow digester is achieving significantly higher conversion than a stirred-tank digester. Of several pretreatment techniques used, only alkaline treatment resulted in increased biodegradability. A larger scale (4.5 m/sup 3/) experimental test unit is being designed for installation at WDW in 1982. 13 figures, 4 tables.« less

Design, fabrication, and testing of a low frequency MEMS piezoelectromagnetic energy harvester

NASA Astrophysics Data System (ADS)

Fernandes, Egon; Martin, Blake; Rua, Isabel; Zarabi, Sid; Debéda, Hélène; Nairn, David; Wei, Lan; Salehian, Armaghan

2018-03-01

This paper details a power solution for smart grid applications to replace batteries by harvesting the electromagnetic energy from a current-carrying wire. A MEMS piezoelectromagnetic energy harvester has been fabricated using PZT screen-printing technology with a centrally-supported meandering geometry. The energy harvesting device employs a symmetric geometry to increase its power output by reducing the effects of the torsional modes and the resultant overall strain nodes in the system subsequently reduce the complexities for the electrode fabrication. The unit is modelled using COMSOL to determine mode shapes and frequency response functions. A 12.7 mm by 14.7 mm unit is fabricated by screen-printing 75 μm-thick PZT on a stainless steel substrate and then experimentally tested to validate the FEA results. Experimentally, the harvester is shown to produce 9 μW from a wire carrying 7 A while operating at a distance of 6.5 mm from the wire. The design of the current work results in a greater normalized power density than other MEMS based piezoelectromagnetic devices and shows great potential relative to larger devices that use bulk or thin film piezoelectrics.

On the Physics of Flow Separation Along a Low Pressure Turbine Blade Under Unsteady Flow Conditions

NASA Technical Reports Server (NTRS)

Schobeiri, Meinhard T.; Ozturk, Burak; Ashpis, David E.

2005-01-01

The present study, which is the first of a series of investigations dealing with specific issues of low pressure turbine (LPT) boundary layer aerodynamics, is aimed at providing detailed unsteady boundary flow information to understand the underlying physics of the inception, onset, and extent of the separation zone. A detailed experimental study on the behavior of the separation zone on the suction surface of a highly loaded LPT-blade under periodic unsteady wake flow is presented. Experimental investigations were performed at Texas A&M Turbomachinery Performance and Flow Research Laboratory using a large-scale unsteady turbine cascade research facility with an integrated wake generator and test section unit. To account for a high flow deflection of LPT-cascades at design and off-design operating points, the entire wake generator and test section unit including the traversing system is designed to allow a precise angle adjustment of the cascade relative to the incoming flow. This is done by a hydraulic platform, which simultaneously lifts and rotates the wake generator and test section unit. The unit is then attached to the tunnel exit nozzle with an angular accuracy of better than 0.05 , which is measured electronically. Utilizing a Reynolds number of 110,000 based on the blade suction surface length and the exit velocity, one steady and two different unsteady inlet flow conditions with the corresponding passing frequencies, wake velocities and turbulence intensities are investigated using hot-wire anemometry. In addition to the unsteady boundary layer measurements, blade surface pressure measurements were performed at Re=50,000, 75,000, 100,000, and 125,000 at one steady and two periodic unsteady inlet flow conditions. Detailed unsteady boundary layer measurement identifies the onset and extent of the separation zone as well as its behavior under unsteady wake flow. The results presented in ensemble-averaged and contour plot forms contribute to understanding the physics of the separation phenomenon under periodic unsteady wake flow. Several physical mechanisms are discussed.

On the physics of unstable infiltration, seepage, and gravity drainage in partially saturated tuffs

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

Faybishenko, B.; Bodvarsson, G.S.; Salve, R.

2002-04-01

To improve understanding of the physics of dynamic instabilities in unsaturated flow processes within the Paintbrush nonwelded unit (PTn) and the middle nonlithophysal portion of the Tonopah Spring welded tuff unit (TSw) of Yucca Mountain, we analyzed data from a series of infiltration tests carried out at two sites (Alcove 4 and Alcove 6) in the Exploratory Studies Facility, using analytical and empirical functions. The analysis of infiltration rates measured at both sites showed three temporal scales of infiltration rate: (1) a macro-scale trend of overall decreasing flow, (2) a meso-scale trend of fast and slow motion exhibiting three-stage variationsmore » of the flow rate (decreasing, increasing, and [again] decreasing flow rate, as observed in soils in the presence of entrapped air), and (3) micro-scale (high frequency) fluctuations. Infiltration tests in the nonwelded unit at Alcove 4 indicate that this unit may effectively dampen episodic fast infiltration events; however, well-known Kostyakov, Horton, and Philip equations do not satisfactorily describe the observed trends of the infiltration rate. Instead, a Weibull distribution model can most accurately describe experimentally determined time trends of the infiltration rate. Infiltration tests in highly permeable, fractured, welded tuff at Alcove 6 indicate that the infiltration rate exhibits pulsation, which may have been caused by multiple threshold effects and water-air redistribution between fractures and matrix. The empirical relationships between the extrinsic seepage from fractures, matrix imbibition, and gravity drainage versus the infiltration rate, as well as scaling and self-similarity for the leading edge of the water front are the hallmark of the nonlinear dynamic processes in water flow under episodic infiltration through fractured tuff. Based on the analysis of experimental data, we propose a conceptual model of a dynamic fracture flow and fracture-matrix interaction in fractured tuff, incorporating the time dependent processes of water redistribution in the fracture-matrix system.« less

On the Physics of Flow Separation Along a Low Pressure Turbine Blade Under Unsteady Flow Conditions

NASA Technical Reports Server (NTRS)

Schobeiri, Meinhard T.; Ozturk, Burak; Ashpis, David E.

2003-01-01

The present study, which is the first of a series of investigations dealing with specific issues of low pressure turbine (LPT) boundary layer aerodynamics, is aimed at providing detailed unsteady boundary flow information to understand the underlying physics of the inception, onset, and extent of the separation zone. A detailed experimental study on the behavior of the separation zone on the suction surface of a highly loaded LPT-blade under periodic unsteady wake flow is presented. Experimental investigations were performed at Texas A&M Turbomachinery Performance and Flow Research Laboratory using a large-scale unsteady turbine cascade research facility with an integrated wake generator and test section unit. To account for a high flow deflection of LPT-cascades at design and off-design operating points, the entire wake generator and test section unit including the traversing system is designed to allow a precise angle adjustment of the cascade relative to the incoming flow. This is done by a hydraulic platform, which simultaneously lifts and rotates the wake generator and test section unit. The unit is then attached to the tunnel exit nozzle with an angular accuracy of better than 0.05 , which is measured electronically. Utilizing a Reynolds number of 110,000 based on the blade suction surface length and the exit velocity, one steady and two different unsteady inlet flowconditions with the corresponding passing frequencies, wake velocities and turbulence intensities are investigated using hot-wire anemometry. In addition to the unsteady boundary layer measurements, blade surface pressure measurements were performed at Re=50,000, 75,000, 100,000, and 125,000 at one steady and two periodic unsteady inlet flow conditions. Detailed unsteady boundary layer measurement identifies the onset and extent of the separation zone as well as its behavior under unsteady wake flow. The results presented in ensemble-averaged and contour plot forms contribute to understanding the physics of the separation phenomenon under periodic unsteady wake flow. Several physical mechanisms are discussed.

Vibration characteristics of walls and a plate glass window representative of those of a wood-frame house

NASA Technical Reports Server (NTRS)

Carden, H. D.

1979-01-01

Mechanical excitation was used, and measurements of acceleration response, natural frequencies, and nodal patterns were performed. Results indicate that the wall sections and the complete wall did not act as a unit in responding to sinusoidal vibration inputs. Calculated frequencies of the components that account for this independent behavior of the studs and face sheets agreed resonably well with experimental frequencies. Experimental vibrations of the plate glass window agreed with the calculated behavior, and responses of the window exposed to airplane flyover noise were readily correlated with the test results.

Superconducting Magnetic Energy Storage (SMES) Program

NASA Astrophysics Data System (ADS)

Rogers, J. D.

1985-05-01

The 30 MJ, 10 MW superconducting magnetic energy storage (SMES) system was devised to interact in the Western US Power System as an alternate means to damp unstable oscillations at 0.35 Hz on the Pacific HVAC Interites. The operating limits of the 30 MJ SMES unit were established, and different means of controlling real and reactive power were tested. The unit can follow a sinusoidal power demand signal with an amplitude of up to 8.6 MW with the converter working in a 12 pulse mode. When the converter operates in the constant VAR mode, a time varying real power demand signal of up to 5 MW can be met. It was shown that the Pacific ac Interite has current and reactive power variations of the same frequency as the modulating frequency of the SMES device. The reliability of the SMES subsystems with a narrow band noise input was assessed. Parameters of the ac power system were determined. Converter short circuit tests, load tests under various control conditions, dc breaker tests for coil current interruption, and converter failure mode tests were conducted. The experimental operation of the SMES system is concluded.

X-38 Experimental Aeroheating at Mach 10

NASA Technical Reports Server (NTRS)

Berry, Scott A.; Horvath, Thomas J.; Weilmuenster, K. James; Alter, Stephan J.; Merski, N. Ronald

2001-01-01

This report provides an update of the hypersonic aerothermodynamic wind tunnel test program conducted at the NASA Langley Research Center in support of the X-38 program. Global surface heat transfer distributions were measured on 0.0177 and 0.0236 scale models of the proposed X-38 configuration at Mach 10 in air. The parametrics that were investigated primarily include freestream unit Reynolds numbers of 0.6 to 2.2 million per foot and body flap deflections of 15, 20, and 25 deg for an angle-of-attack of 40 deg. The model-scale variance was tested to obtain laminar, transitional, and turbulent heating levels on the defected bodyflaps. In addition, a limited investigation of forced boundary layer transition through the use of discrete roughness elements was performed. Comparisons of the present experimental results to computational predictions and previous experimental data were conducted Laminar, transitional, and turbulent heating levels were observed on the deflected body flap, which compared favorably to the computational results and to the predicted heating based on the flight aerothermodynamic database.

Fuel alcohol production from agricultural lignocellulosic feedstocks

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

Farina, G.E.; Barrier, J.W.; Forsythe, M.L.

1988-01-01

A two-stage, low-temperature, ambient pressure, acid hydrolysis process that utilizes separate unit operations to convert hemicellulose and cellulose in agricultural residues and crops to fermentable sugars is being developed and tested. Based on the results of the bench-scale tests, an acid hydrolysis experimental plant to demonstrate the concepts of low-temperature acid hydrolysis on a much larger scale was built. Plant tests using corn stover have been conducted for more that a year and conversion efficiences have equaled those achieved in the laboratory. Laboratory tests to determine the potential for low-temperature acid hydrolysis of other feedstocks - including red clover, alfalfa,more » kobe lespedeza, winter rape, and rye grass - are being conducted. Where applicable, process modifications to include extraction before or after hydrolysis also are being studied. This paper describes the experimental plant and process, results obtained in the plant, results of alternative feedstocks testing in the laboratory, and a plan for an integrated system that will produce other fuels, feed, and food from crops grown on marginal land.« less

Physiological Event Prediction in Evaluations of Underwater Breathing Apparatus

DTIC Science & Technology

2016-10-25

Navy Experimental Diving Unit TA 15-02 321 Bullfinch Rd. NEDU TR 16-04 Panama City, FL 32407-7015 October 2016 Physiological...Event Prediction in Evaluations of Underwater Breathing Apparatus NAVY EXPERIMENTAL DIVING UNIT Author...5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER Navy Experimental

Collaborative testing: assessing teamwork and critical thinking behaviors in baccalaureate nursing students.

PubMed

Wiggs, Carol M

2011-04-01

The purpose of this study was to foster teamwork and critical thinking behaviors in baccalaureate nursing students using a collaborative testing environment. Collaborative testing affords the nurse educator a unique opportunity to actively influence the development of critical thinking skills directly influencing the nursing student's ability to solve complex patient problems. Using a quasi-experimental approach exam scores from students in prior semesters were compared to students in several semesters using collaborative testing in one undergraduate course taught by the same faculty. In the experimental group collaborative testing was used in the two unit examinations, while the final examination remained individual. For collaborative testing the students were grouped by random assignment. They were not allowed the use of notes, textbooks, or other resource materials. Any student who wished to work alone was allowed do so and any student coming late (within 15 min of examination beginning) was required to work alone. Each student submitted individual examination answer forms, and groups were not required to reach consensus. Collaborative testing is one means to foster critical thinking by allowing students to solve complex patient problems within an examination environment. This better prepares them for national certification exams. Copyright © 2010 Elsevier Ltd. All rights reserved.

Evaluation of shear bond strength of orthodontic brackets using trans-illumination technique with different curing profiles of LED light-curing unit in posterior teeth.

PubMed

Heravi, Farzin; Moazzami, Saied Mostafa; Ghaffari, Negin; Jalayer, Javad; Bozorgnia, Yasaman

2013-11-21

Although using light-cured composites for bonding orthodontic brackets has become increasingly popular, curing light cannot penetrate the metallic bulk of brackets and polymerization of composites is limited to the edges. Limited access and poor direct sight may be a problem in the posterior teeth. Meanwhile, effectiveness of the trans-illumination technique is questionable due to increased bucco-lingual thickness of the posterior teeth. Light-emitting diode (LED) light-curing units cause less temperature rise and lower risk to the pulpal tissue. The purpose of this study was to evaluate the clinical effectiveness of trans-illumination technique in bonding metallic brackets to premolars, using different light intensities and curing times of an LED light-curing unit. Sixty premolars were randomly divided into six groups. Bonding of brackets was done with 40- and 80-s light curing from the buccal or lingual aspect with different intensities. Shear bond strengths of brackets were measured using a universal testing machine. Data were analyzed by one-way analysis of variance test and Duncan's post hoc test. The highest shear bond belonged to group 2 (high intensity, 40 s, buccal) and the lowest belonged to group 3 (low intensity, 40 s, lingual). Bond strength means in control groups were significantly higher than those in experimental groups. In all experimental groups except group 6 (80 s, high intensity, lingual), shear bond strength was below the clinically accepted values. In clinical limitations where light curing from the same side of the bracket is not possible, doubling the curing time and increasing the light intensity during trans-illumination are recommended for achieving acceptable bond strengths.

Effects of in situ CO2 enrichment on structural characteristics, photosynthesis, and growth of the Mediterranean seagrass Posidonia oceanica

NASA Astrophysics Data System (ADS)

Cox, T. Erin; Gazeau, Frédéric; Alliouane, Samir; Hendriks, Iris E.; Mahacek, Paul; Le Fur, Arnaud; Gattuso, Jean-Pierre

2016-04-01

Seagrass is expected to benefit from increased carbon availability under future ocean acidification. This hypothesis has been little tested by in situ manipulation. To test for ocean acidification effects on seagrass meadows under controlled CO2/pH conditions, we used a Free Ocean Carbon Dioxide Enrichment (FOCE) system which allows for the manipulation of pH as continuous offset from ambient. It was deployed in a Posidonia oceanica meadow at 11 m depth in the Northwestern Mediterranean Sea. It consisted of two benthic enclosures, an experimental and a control unit both 1.7 m3, and an additional reference plot in the ambient environment (2 m2) to account for structural artifacts. The meadow was monitored from April to November 2014. The pH of the experimental enclosure was lowered by 0.26 pH units for the second half of the 8-month study. The greatest magnitude of change in P. oceanica leaf biometrics, photosynthesis, and leaf growth accompanied seasonal changes recorded in the environment and values were similar between the two enclosures. Leaf thickness may change in response to lower pH but this requires further testing. Results are congruent with other short-term and natural studies that have investigated the response of P. oceanica over a wide range of pH. They suggest any benefit from ocean acidification, over the next century (at a pH of ˜ 7.7 on the total scale), on Posidonia physiology and growth may be minimal and difficult to detect without increased replication or longer experimental duration. The limited stimulation, which did not surpass any enclosure or seasonal effect, casts doubts on speculations that elevated CO2 would confer resistance to thermal stress and increase the buffering capacity of meadows.

Bioresorbable scaffolds for bone tissue engineering: optimal design, fabrication, mechanical testing and scale-size effects analysis.

PubMed

Coelho, Pedro G; Hollister, Scott J; Flanagan, Colleen L; Fernandes, Paulo R

2015-03-01

Bone scaffolds for tissue regeneration require an optimal trade-off between biological and mechanical criteria. Optimal designs may be obtained using topology optimization (homogenization approach) and prototypes produced using additive manufacturing techniques. However, the process from design to manufacture remains a research challenge and will be a requirement of FDA design controls to engineering scaffolds. This work investigates how the design to manufacture chain affects the reproducibility of complex optimized design characteristics in the manufactured product. The design and prototypes are analyzed taking into account the computational assumptions and the final mechanical properties determined through mechanical tests. The scaffold is an assembly of unit-cells, and thus scale size effects on the mechanical response considering finite periodicity are investigated and compared with the predictions from the homogenization method which assumes in the limit infinitely repeated unit cells. Results show that a limited number of unit-cells (3-5 repeated on a side) introduce some scale-effects but the discrepancies are below 10%. Higher discrepancies are found when comparing the experimental data to numerical simulations due to differences between the manufactured and designed scaffold feature shapes and sizes as well as micro-porosities introduced by the manufacturing process. However good regression correlations (R(2) > 0.85) were found between numerical and experimental values, with slopes close to 1 for 2 out of 3 designs. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

Experimental control requirements for life sciences

NASA Technical Reports Server (NTRS)

Berry, W. E.; Sharp, J. C.

1978-01-01

The Life Sciences dedicated Spacelab will enable scientists to test hypotheses in various disciplines. Building upon experience gained in mission simulations, orbital flight test experiments, and the first three Spacelab missions, NASA will be able to progressively develop the engineering and management capabilities necessary for the first Life Sciences Spacelab. Development of experiments for these missions will require implementation of life-support systems not previously flown in space. Plant growth chambers, animal holding facilities, aquatic specimen life-support systems, and centrifuge-mounted specimen holding units are examples of systems currently being designed and fabricated for flight.

Experimental Investigations from the Operation of a 2 Kw Brayton Power Conversion Unit and a Xenon Ion Thruster

NASA Technical Reports Server (NTRS)

Mason, Lee; Birchenough, Arthur; Pinero, Luis

2004-01-01

A 2 kW Brayton Power Conversion Unit (PCU) and a xenon ion thruster were integrated with a Power Management and Distribution (PMAD) system as part of a Nuclear Electric Propulsion (NEP) Testbed at NASA's Glenn Research Center. Brayton converters and ion thrusters are potential candidates for use on future high power NEP missions such as the proposed Jupiter Icy Moons Orbiter (JIMO). The use of existing lower power test hardware provided a cost-effective means to investigate the critical electrical interface between the power conversion system and ion propulsion system. The testing successfully demonstrated compatible electrical operations between the converter and the thruster, including end-to-end electric power throughput, high efficiency AC to DC conversion, and thruster recycle fault protection. The details of this demonstration are reported herein.

Experimental Investigation from the Operation of a 2 kW Brayton Power Conversion Unit and a Xenon Ion Thruster

NASA Technical Reports Server (NTRS)

Hervol, David; Mason, Lee; Birchenough, Art; Pinero, Luis

2004-01-01

A 2kW Brayton Power Conversion Unit (PCU) and a xenon ion thruster were integrated with a Power Management and Distribution (PMAD) system as part of a Nuclear Electric Propulsion (NEP) Testbed at NASA's Glenn Research Center. Brayton Converters and ion thrusters are potential candidates for use on future high power NEP mission such as the proposed Jupiter Icy Moons Orbiter (JIMO). The use of a existing lower power test hardware provided a cost effective means to investigate the critical electrical interface between the power conversion system and the propulsion system. The testing successfully demonstrated compatible electrical operations between the converter and the thruster, including end-to-end electric power throughput, high efficiency AC to DC conversion, and thruster recycle fault protection. The details of this demonstration are reported herein.

Development of Electric Power Units Driven by Waste Heat

NASA Astrophysics Data System (ADS)

Inoue, Naoyuki; Takeuchi, Takao; Kaneko, Atsushi; Uchimura, Tomoyuki; Irie, Kiichi; Watanabe, Hiroyoshi

For the development of a simple and compact power generator driven by waste heat, working fluids and an expander were studied, then a practical electric power unit was put to test. Many working fluids were calculated with the low temperature power cycle (evaporated at 77°C, condensed at 42°C),and TFE,R123,R245fa were selected to be suitable for the cycle. TFE(Trifluoroethanol CF3CH2OH) was adopted to the actual power generator which was tested. A radial turbine was adopted as an expander, and was newly designed and manufactured for working fluid TFE. The equipment was driven by hot water as heat source and cooling water as cooling source, and generated power was connected with electric utility. Characteristics of the power generating cycle and characteristics of the turbine were obtained experimentally.

Light and short arc rubs in rotating machines: Experimental tests and modelling

NASA Astrophysics Data System (ADS)

Pennacchi, P.; Bachschmid, N.; Tanzi, E.

2009-10-01

Rotor-to-stator rub is a non-linear phenomenon which has been analyzed many times in rotordynamics literature, but very often these studies are devoted simply to highlight non-linearities, using very simple rotors, rather than to present reliable models. However, rotor-to-stator rub is actually one of the most common faults during the operation of rotating machinery. The frequency of its occurrence is increasing due to the trend of reducing the radial clearance between the seal and the rotor in modern turbine units, pumps and compressors in order to increase efficiency. Often the rub occurs between rotor and seals and the analysis of the phenomenon cannot set aside the consideration of the different relative stiffness. This paper presents some experimental results obtained by means of a test rig in which rub conditions of real machines are reproduced. In particular short arc rubs are considered and the shaft is stiffer than the obstacle. Then a model, suitable to be employed for real rotating machinery, is presented and the simulations obtained are compared with the experimental results. The model is able to reproduce the behaviour of the test rig.

Experimental Characterization and Micromechanical Modeling of Woven Carbon/Copper Composites

NASA Technical Reports Server (NTRS)

Bednarcyk, Brett A.; Pauly, Christopher C.; Pindera, Marek-Jerzy

1997-01-01

The results of an extensive experimental characterization and a preliminary analytical modeling effort for the elastoplastic mechanical behavior of 8-harness satin weave carbon/copper (C/Cu) composites are presented. Previous experimental and modeling investigations of woven composites are discussed, as is the evolution of, and motivation for, the continuing research on C/Cu composites. Experimental results of monotonic and cyclic tension, compression, and Iosipescu shear tests, and combined tension-compression tests, are presented. With regard to the test results, emphasis is placed on the effect of strain gauge size and placement, the effect of alloying the copper matrix to improve fiber-matrix bonding, yield surface characterization, and failure mechanisms. The analytical methodology used in this investigation consists of an extension of the three-dimensional generalized method of cells (GMC-3D) micromechanics model, developed by Aboudi (1994), to include inhomogeneity and plasticity effects on the subcell level. The extension of the model allows prediction of the elastoplastic mechanical response of woven composites, as represented by a true repeating unit cell for the woven composite. The model is used to examine the effects of refining the representative geometry of the composite, altering the composite overall fiber volume fraction, changing the size and placement of the strain gauge with respect to the composite's reinforcement weave, and including porosity within the infiltrated fiber yarns on the in-plane elastoplastic tensile, compressive, and shear response of 8-harness satin C/Cu. The model predictions are also compared with the appropriate monotonic experimental results.

A comparison of three erosion control mulches on decommissioned forest road corridors in the northern Rocky Mountains, United States

Treesearch

R. B. Foltz

2012-01-01

This study tested the erosion mitigation effectiveness of agricultural straw and two wood-based mulches for four years on decommissioned forest roads. Plots were installed on the loosely consolidated, bare soil to measure sediment production, mulch cover, and plant regrowth. The experimental design was a repeated measures, randomized block on two soil types common in...

Response of nesting northern goshawks to logging truck noise in northern Arizona

Treesearch

Teryl G. Grubb; Larry L. Pater; Angela E. Gatto; David K. Delaney

2013-01-01

We recorded 94 sound-response events at 3 adult-occupied northern goshawk (Accipiter gentilis) nests 78 m, 143 m, and 167m from the nearest United States Forest Service maintenance level 3, improved gravel road on the Kaibab Plateau in northern Arizona. During 4 test sessions on 7, 8, 10, and 11 June 2010, we recorded 60 experimentally controlled logging trucks; 30 non...

Quantitative computer simulations of extraterrestrial processing operations

NASA Technical Reports Server (NTRS)

Vincent, T. L.; Nikravesh, P. E.

1989-01-01

The automation of a small, solid propellant mixer was studied. Temperature control is under investigation. A numerical simulation of the system is under development and will be tested using different control options. Control system hardware is currently being put into place. The construction of mathematical models and simulation techniques for understanding various engineering processes is also studied. Computer graphics packages were utilized for better visualization of the simulation results. The mechanical mixing of propellants is examined. Simulation of the mixing process is being done to study how one can control for chaotic behavior to meet specified mixing requirements. An experimental mixing chamber is also being built. It will allow visual tracking of particles under mixing. The experimental unit will be used to test ideas from chaos theory, as well as to verify simulation results. This project has applications to extraterrestrial propellant quality and reliability.

Advanced air revitalization system testing

NASA Technical Reports Server (NTRS)

Heppner, D. B.; Hallick, T. M.; Schubert, F. H.

1983-01-01

A previously developed experimental air revitalization system was tested cyclically and parametrically. One-button startup without manual interventions; extension by 1350 hours of tests with the system; capability for varying process air carbon dioxide partial pressure and humidity and coolant source for simulation of realistic space vehicle interfaces; dynamic system performance response on the interaction of the electrochemical depolarized carbon dioxide concentrator, the Sabatier carbon dioxide reduction subsystem, and the static feed water electrolysis oxygen generation subsystem, the carbon dioxide concentrator module with unitized core technology for the liquid cooled cell; and a preliminary design for a regenerative air revitalization system for the space station are discussed.

Unitized Stiffened Composite Textile Panels: Manufacturing, Characterization, Experiments, and Analysis

NASA Astrophysics Data System (ADS)

Kosztowny, Cyrus Joseph Robert

Use of carbon fiber textiles in complex manufacturing methods creates new implementations of structural components by increasing performance, lowering manufacturing costs, and making composites overall more attractive across industry. Advantages of textile composites include high area output, ease of handling during the manufacturing process, lower production costs per material used resulting from automation, and provide post-manufacturing assembly mainstreaming because significantly more complex geometries such as stiffened shell structures can be manufactured with fewer pieces. One significant challenge with using stiffened composite structures is stiffener separation under compression. Axial compression loading conditions have frequently observed catastrophic structural failure due to stiffeners separating from the shell skin. Characterizing stiffener separation behavior is often costly computationally and experimentally. The objectives of this research are to demonstrate unitized stiffened textile composite panels can be manufactured to produce quality test specimens, that existing characterization techniques applied to state-of-the-art high-performance composites provide valuable information in modeling such structures, that the unitized structure concept successfully removes stiffener separation as a primary structural failure mode, and that modeling textile material failure modes are sufficient to accurately capture postbuckling and final failure responses of the stiffened structures. The stiffened panels in this study have taken the integrally stiffened concept to an extent such that the stiffeners and skin are manufactured at the same time, as one single piece, and from the same composite textile layers. Stiffener separation is shown to be removed as a primary structural failure mode for unitized stiffened composite textile panels loaded under axial compression well into the postbuckling regime. Instead of stiffener separation, a material damaging and failure model effectively captures local post-peak material response via incorporating a mesoscale model using a multiscaling framework with a smeared crack element-based failure model in the macroscale stiffened panel. Material damage behavior is characterized by simple experimental tests and incorporated into the post-peak stiffness degradation law in the smeared crack implementation. Computational modeling results are in overall excellent agreement compared to the experimental responses.

Experimental muscle pain produces central modulation of proprioceptive signals arising from jaw muscle spindles.

PubMed

Capra, N F; Ro, J Y

2000-05-01

The aim of the present study was to investigate the effects of intramuscular injection with hypertonic saline, a well-established experimental model for muscle pain, on central processing of proprioceptive input from jaw muscle spindle afferents. Fifty-seven cells were recorded from the medial edge of the subnucleus interpolaris (Vi) and the adjacent parvicellular reticular formation from 11 adult cats. These cells were characterized as central units receiving jaw muscle spindle input based on their responses to electrical stimulation of the masseter nerve, muscle palpation and jaw stretch. Forty-five cells, which were successfully tested with 5% hypertonic saline, were categorized as either dynamic-static (DS) (n=25) or static (S) (n=20) neurons based on their responses to different speeds and amplitudes of jaw movement. Seventy-six percent of the cells tested with an ipsilateral injection of hypertonic saline showed a significant modulation of mean firing rates (MFRs) during opening and/or holding phases. The most remarkable saline-induced change was a significant reduction of MFR during the hold phase in S units (100%, 18/18 modulated). Sixty-nine percent of the DS units (11/16 modulated) also showed significant changes in MFRs limited to the hold phase. However, in the DS neurons, the MFRs increased in seven units and decreased in four units. Finally, five DS neurons showed significant changes of MFRs during both opening and holding phases. Injections of isotonic saline into the ipsilateral masseter muscle had little effect, but hypertonic saline injections made into the contralateral masseter muscle produced similar results to ipsilateral injections with hypertonic saline. These results unequivocally demonstrate that intramuscular injection with an algesic substance, sufficient to produce muscle pain, produces significant changes in the proprioceptive properties of the jaw movement-related neurons. Potential mechanisms involved in saline-induced changes in the proprioceptive signals and functional implications of the changes are discussed.

Experimental design, operation, and results of a 4 kW high temperature steam electrolysis experiment

DOE PAGES

Zhang, Xiaoyu; O'Brien, James E.; Tao, Greg; ...

2015-08-06

High temperature steam electrolysis (HTSE) is a promising technology for large-scale hydrogen production. However, research on HTSE performance above the kW level is limited. This paper presents the results of 4 kW HTSE long-term test completed in a multi-kW test facility recently developed at the Idaho National Laboratory (INL). The 4 kW HTSE unit included two solid oxide electrolysis stacks operating in parallel, each of which included 40 electrode-supported planar cells. A current density of 0.41 A/cm2 was used for the long-term operation, resulting in a hydrogen production rate about 25 slpm. A demonstration of 920 hours stable operation wasmore » achieved. The paper also includes detailed descriptions of the piping layout, steam generation and delivery system, test fixture, heat recuperation system, hot zone, instrumentation, and operating conditions. As a result, this successful demonstration of multi-kW scale HTSE unit will help to advance the technology toward near-term commercialization.« less

A New Test Unit for Disintegration End-Point Determination of Orodispersible Films.

PubMed

Low, Ariana; Kok, Si Ling; Khong, Yuet Mei; Chan, Sui Yung; Gokhale, Rajeev

2015-11-01

No standard time or pharmacopoeia disintegration test method for orodispersible films (ODFs) exists. The USP disintegration test for tablets and capsules poses significant challenges for end-point determination when used for ODFs. We tested a newly developed disintegration test unit (DTU) against the USP disintegration test. The DTU is an accessory to the USP disintegration apparatus. It holds the ODF in a horizontal position, allowing top-view of the ODF during testing. A Gauge R&R study was conducted to assign relative contributions of the total variability from the operator, sample or the experimental set-up. Precision was compared using commercial ODF products in different media. Agreement between the two measurement methods was analysed. The DTU showed improved repeatability and reproducibility compared to the USP disintegration system with tighter standard deviations regardless of operator or medium. There is good agreement between the two methods, with the USP disintegration test giving generally longer disintegration times possibly due to difficulty in end-point determination. The DTU provided clear end-point determination and is suitable for quality control of ODFs during product developmental stage or manufacturing. This may facilitate the development of a standardized methodology for disintegration time determination of ODFs. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

[Effect of manual cleaning and machine cleaning for dental handpiece].

PubMed

Zhou, Xiaoli; Huang, Hao; He, Xiaoyan; Chen, Hui; Zhou, Xiaoying

2013-08-01

Comparing the dental handpiece' s cleaning effect between manual cleaning and machine cleaning. Eighty same contaminated dental handpieces were randomly divided into experimental group and control group, each group contains 40 pieces. The experimental group was treated by full automatic washing machine, and the control group was cleaned manually. The cleaning method was conducted according to the operations process standard, then ATP bioluminescence was used to test the cleaning results. Average relative light units (RLU) by ATP bioluminescence detection were as follows: Experimental group was 9, control group was 41. The two groups were less than the recommended RLU value provided by the instrument manufacturer (RLU < or = 45). There was significant difference between the two groups (P < 0.05). The cleaning quality of the experimental group was better than that of control group. It is recommended that the central sterile supply department should clean dental handpieces by machine to ensure the cleaning effect and maintain the quality.

Experimental Investigation of Textile Composite Materials Using Moire Interferometry

NASA Technical Reports Server (NTRS)

Ifju, Peter G.

1995-01-01

The viability as an efficient aircraft material of advanced textile composites is currently being addressed in the NASA Advanced Composites Technology (ACT) Program. One of the expected milestones of the program is to develop standard test methods for these complex material systems. Current test methods for laminated composites may not be optimum for textile composites, since the architecture of the textile induces nonuniform deformation characteristics on the scale of the smallest repeating unit of the architecture. The smallest repeating unit, also called the unit cell, is often larger than the strain gages used for testing of tape composites. As a result, extending laminated composite test practices to textiles can often lead to pronounced scatter in material property measurements. It has been speculated that the fiber architectures produce significant surface strain nonuniformities, however, the magnitudes were not well understood. Moire interferometry, characterized by full-field information, high displacement sensitivity, and high spatial resolution, is well suited to document the surface strain on textile composites. Studies at the NASA Langley Research Center on a variety of textile architectures including 2-D braids and 3-D weaves, has evidenced the merits of using moire interferometry to guide in test method development for textile composites. Moire was used to support tensile testing by validating instrumentation practices and documenting damage mechanisms. It was used to validate shear test methods by mapping the full-field deformation of shear specimens. Moire was used to validate open hole tension experiments to determine the strain concentration and compare then to numeric predictions. It was used for through-the-thickness tensile strength test method development, to verify capabilities for testing of both 2-D and 3-D material systems. For all of these examples, moire interferometry provided vision so that test methods could be developed with less speculation and more documentation.

International Space Station

NASA Technical Reports Server (NTRS)

1998-01-01

This artist's digital concept depicts the completely assembled International Space Station (ISS) passing over Florida. As a gateway to permanent human presence in space, the Space Station Program is to expand knowledge benefiting all people and nations. The ISS is a multidisciplinary laboratory, technology test bed, and observatory that will provide unprecedented undertakings in scientific, technological, and international experimentation. Experiments to be conducted in the ISS include: microgravity research, Earth science, space science, life sciences, space product development, and engineering research and technology. The sixteen countries participating the ISS are: United States, Russian Federation, Canada, Japan, United Kingdom, Germany, Italy, France, Norway, Netherlands, Belgium, Spain, Denmark, Sweden, Switzerland, and Brazil.

International Space Station

NASA Technical Reports Server (NTRS)

1998-01-01

This artist's concept depicts the completely assembled International Space Station (ISS) passing over the Straits of Gibraltar and the Mediterranean Sea. As a gateway to permanent human presence in space, the Space Station Program is to expand knowledge benefiting all people and nations. The ISS is a multidisciplinary laboratory, technology test bed, and observatory that will provide unprecedented undertakings in scientific, technological, and international experimentation. Experiments to be conducted in the ISS include: microgravity research, Earth science, space science, life sciences, space product development, and engineering research and technology. The sixteen countries participating the ISS are: United States, Russian Federation, Canada, Japan, United Kingdom, Germany, Italy, France, Norway, Netherlands, Belgium, Spain, Denmark, Sweden, Switzerland, and Brazil.

International Space Station

NASA Technical Reports Server (NTRS)

1998-01-01

This artist's concept depicts the completely assembled International Space Station (ISS) passing over Florida and the Bahamas. As a gateway to permanent human presence in space, the Space Station Program is to expand knowledge benefiting all people and nations. The ISS is a multidisciplinary laboratory, technology test bed, and observatory that will provide unprecedented undertakings in scientific, technological, and international experimentation. Experiments to be conducted in the ISS include: microgravity research, Earth science, space science, life sciences, space product development, and engineering research and technology. The sixteen countries participating in the ISS are: United States, Russian Federation, Canada, Japan, United Kingdom, Germany, Italy, France, Norway, Netherlands, Belgium, Spain, Denmark, Sweden, Switzerland, and Brazil.

International Space Station (ISS)

NASA Image and Video Library

1998-01-01

This artist's concept depicts the completely assembled International Space Station (ISS) passing over Florida and the Bahamas. As a gateway to permanent human presence in space, the Space Station Program is to expand knowledge benefiting all people and nations. The ISS is a multidisciplinary laboratory, technology test bed, and observatory that will provide unprecedented undertakings in scientific, technological, and international experimentation. Experiments to be conducted in the ISS include: microgravity research, Earth science, space science, life sciences, space product development, and engineering research and technology. The sixteen countries participating in the ISS are: United States, Russian Federation, Canada, Japan, United Kingdom, Germany, Italy, France, Norway, Netherlands, Belgium, Spain, Denmark, Sweden, Switzerland, and Brazil.

International Space Station (ISS)

NASA Image and Video Library

1998-01-01

This artist's digital concept depicts the completely assembled International Space Station (ISS) passing over Florida. As a gateway to permanent human presence in space, the Space Station Program is to expand knowledge benefiting all people and nations. The ISS is a multidisciplinary laboratory, technology test bed, and observatory that will provide unprecedented undertakings in scientific, technological, and international experimentation. Experiments to be conducted in the ISS include: microgravity research, Earth science, space science, life sciences, space product development, and engineering research and technology. The sixteen countries participating the ISS are: United States, Russian Federation, Canada, Japan, United Kingdom, Germany, Italy, France, Norway, Netherlands, Belgium, Spain, Denmark, Sweden, Switzerland, and Brazil.

Signal conditioning units for vibration measurement in HUMS

NASA Astrophysics Data System (ADS)

Wu, Kaizhi; Liu, Tingting; Yu, Zirong; Chen, Lijuan; Huang, Xinjie

2018-03-01

A signal conditioning units for vibration measurement in HUMS is proposed in the paper. Due to the frequency of vibrations caused by components in helicopter are different, two steps amplifier and programmable anti-aliasing filter are designed to meet the measurement of different types of helicopter. Vibration signals are converted into measurable electrical signals combing with ICP driver firstly. Then pre-amplifier and programmable gain amplifier is applied to magnify the weak electrical signals. In addition, programmable anti-aliasing filter is utilized to filter the interference of noise. The units were tested using function signal generator and oscilloscope. The experimental results have demonstrated the effectiveness of our proposed method in quantitatively and qualitatively. The method presented in this paper can meet the measurement requirement for different types of helicopter.

Parallel In Vivo DNA Assembly by Recombination: Experimental Demonstration and Theoretical Approaches

PubMed Central

Shi, Zhenyu; Wedd, Anthony G.; Gras, Sally L.

2013-01-01

The development of synthetic biology requires rapid batch construction of large gene networks from combinations of smaller units. Despite the availability of computational predictions for well-characterized enzymes, the optimization of most synthetic biology projects requires combinational constructions and tests. A new building-brick-style parallel DNA assembly framework for simple and flexible batch construction is presented here. It is based on robust recombination steps and allows a variety of DNA assembly techniques to be organized for complex constructions (with or without scars). The assembly of five DNA fragments into a host genome was performed as an experimental demonstration. PMID:23468883

Evaluation of Selected Chemical Processes for Production of Low-cost Silicon, Phase 3

NASA Technical Reports Server (NTRS)

Blocher, J. M.; Browning, M. F.

1979-01-01

Refinements of the design of the 50 MT/year Experimental Process System Development Unit were made and competitive bids were received from mechanical, electrical, and structural contractors. Bids on most of the equipment were received and cataloged. Emergency procedures were defined to counter a variety of contingencies disclosed in operations and safety reviews. Experimental work with an electrolytic cell for zinc chloride disclosed no significant increase in power efficiency by steps taken to increase electrolyte circulation. On the basis of materials compatibility and permeability tests, 310 stainless steel was chosen for the shell of the fluidized-bed reactor and SiC-coated graphite for the liner.

Aerothermodynamic Insight From The HIFIRE Program

NASA Astrophysics Data System (ADS)

Kimmel, Roger L.; Adamczak, David; Dolvin, Douglas; Borg, Matthew; Stanfield, Scott

2011-05-01

The HIFiRE (Hypersonic International Flight Research and Experimentation) program is a joint venture of the United States Air Force Research Laboratory and Australian Defence Science and Technology Organisation to utilize economical flight research opportunities in the exploration of flight science issues for space access systems. Flights 1 and 5 focus on collecting high-resolution experimental data on critical aerothermodynamic phenomena, including laminar-turbulent transition and shock/boundary layer interactions. Flight 1, successfully flown in March 2010, employed a test article composed of a 7-deg right angle cone, followed by a cylinder and flare. The test article remained attached to the second-stage booster throughout the ballistic trajectory. Flight 5, to be launched in a similar fashion, will feature a 2:1 elliptic cross-section cone as the test article. For both flights significant resources have been invested in pre-flight aerothermodynamic analysis and testing. This manuscript will summarize the overall strategy of the HIFiRE program, review the pre-flight aerothermodynamic analysis for Flights 1 and 5, and present a brief look at preliminary results from the post-flight analysis of Flight 1.

Internal consistency tests for evaluation of measurements of anthropogenic hydrocarbons in the troposphere

NASA Astrophysics Data System (ADS)

Parrish, D. D.; Trainer, M.; Young, V.; Goldan, P. D.; Kuster, W. C.; Jobson, B. T.; Fehsenfeld, F. C.; Lonneman, W. A.; Zika, R. D.; Farmer, C. T.; Riemer, D. D.; Rodgers, M. O.

1998-09-01

Measurements of tropospheric nonmethane hydrocarbons (NMHCs) made in continental North America should exhibit a common pattern determined by photochemical removal and dilution acting upon the typical North American urban emissions. We analyze 11 data sets collected in the United States in the context of this hypothesis, in most cases by analyzing the geometric mean and standard deviations of ratios of selected NMHCs. In the analysis we attribute deviations from the common pattern to plausible systematic and random experimental errors. In some cases the errors have been independently verified and the specific causes identified. Thus this common pattern provides a check for internal consistency in NMHC data sets. Specific tests are presented which should provide useful diagnostics for all data sets of anthropogenic NMHC measurements collected in the United States. Similar tests, based upon the perhaps different emission patterns of other regions, presumably could be developed. The specific tests include (1) a lower limit for ethane concentrations, (2) specific NMHCs that should be detected if any are, (3) the relatively constant mean ratios of the longer-lived NMHCs with similar atmospheric lifetimes, (4) the constant relative patterns of families of NMHCs, and (5) limits on the ambient variability of the NMHC ratios. Many experimental problems are identified in the literature and the Southern Oxidant Study data sets. The most important conclusion of this paper is that a rigorous field intercomparison of simultaneous measurements of ambient NMHCs by different techniques and researchers is of crucial importance to the field of atmospheric chemistry. The tests presented here are suggestive of errors but are not definitive; only a field intercomparison can resolve the uncertainties.

The Effects of Kangaroo Care in the Neonatal Intensive Care Unit on the Physiological Functions of Preterm Infants, Maternal-Infant Attachment, and Maternal Stress.

PubMed

Cho, Eun-Sook; Kim, Shin-Jeong; Kwon, Myung Soon; Cho, Haeryun; Kim, Eun Hye; Jun, Eun Mi; Lee, Sunhee

2016-01-01

This study was conducted to identify the effects of kangaroo care on the physiological functions of preterm infants, maternal-infant attachment, and maternal stress. For this study, a quasi-experiment design was used with a nonequivalent control group, and a pre- and post-test. Data were collected from preterm infants with corrected gestational ages of ≥33weeks who were hospitalized between May and October 2011. Twenty infants were assigned to the experimental group and 20 to the control group. As an intervention, kangaroo care was provided in 30-min sessions conducted thrice a week for a total of 10 times. The collected data were analyzed by using the t test, repeated-measures ANOVA, and the ANCOVA test. After kangaroo care, the respiration rate significantly differed between the two groups (F=5.701, p=.020). The experimental group had higher maternal-infant attachment scores (F=25.881, p<.001) and lower maternal stress scores (F=47.320, p<.001) than the control group after the test. In other words, kangaroo care showed significantly positive effects on stabilizing infant physiological functions such as respiration rate, increasing maternal-infant attachment, and reducing maternal stress. This study suggests that kangaroo care can be used to promote emotional bonding and support between mothers and their babies, and to stabilize the physiological functions of premature babies. Kangaroo care may be one of the most effective nursing interventions in the neonatal intensive care unit for the care of preterm infants and their mothers. Copyright © 2016 Elsevier Inc. All rights reserved.

Micromechanics Fatigue Damage Analysis Modeling for Fabric Reinforced Ceramic Matrix Composites

NASA Technical Reports Server (NTRS)

Min, J. B.; Xue, D.; Shi, Y.

2013-01-01

A micromechanics analysis modeling method was developed to analyze the damage progression and fatigue failure of fabric reinforced composite structures, especially for the brittle ceramic matrix material composites. A repeating unit cell concept of fabric reinforced composites was used to represent the global composite structure. The thermal and mechanical properties of the repeating unit cell were considered as the same as those of the global composite structure. The three-phase micromechanics, the shear-lag, and the continuum fracture mechanics models were integrated with a statistical model in the repeating unit cell to predict the progressive damages and fatigue life of the composite structures. The global structure failure was defined as the loss of loading capability of the repeating unit cell, which depends on the stiffness reduction due to material slice failures and nonlinear material properties in the repeating unit cell. The present methodology is demonstrated with the analysis results evaluated through the experimental test performed with carbon fiber reinforced silicon carbide matrix plain weave composite specimens.

Plant Disease Severity Assessment-How Rater Bias, Assessment Method, and Experimental Design Affect Hypothesis Testing and Resource Use Efficiency.

PubMed

Chiang, Kuo-Szu; Bock, Clive H; Lee, I-Hsuan; El Jarroudi, Moussa; Delfosse, Philippe

2016-12-01

The effect of rater bias and assessment method on hypothesis testing was studied for representative experimental designs for plant disease assessment using balanced and unbalanced data sets. Data sets with the same number of replicate estimates for each of two treatments are termed "balanced" and those with unequal numbers of replicate estimates are termed "unbalanced". The three assessment methods considered were nearest percent estimates (NPEs), an amended 10% incremental scale, and the Horsfall-Barratt (H-B) scale. Estimates of severity of Septoria leaf blotch on leaves of winter wheat were used to develop distributions for a simulation model. The experimental designs are presented here in the context of simulation experiments which consider the optimal design for the number of specimens (individual units sampled) and the number of replicate estimates per specimen for a fixed total number of observations (total sample size for the treatments being compared). The criterion used to gauge each method was the power of the hypothesis test. As expected, at a given fixed number of observations, the balanced experimental designs invariably resulted in a higher power compared with the unbalanced designs at different disease severity means, mean differences, and variances. Based on these results, with unbiased estimates using NPE, the recommended number of replicate estimates taken per specimen is 2 (from a sample of specimens of at least 30), because this conserves resources. Furthermore, for biased estimates, an apparent difference in the power of the hypothesis test was observed between assessment methods and between experimental designs. Results indicated that, regardless of experimental design or rater bias, an amended 10% incremental scale has slightly less power compared with NPEs, and that the H-B scale is more likely than the others to cause a type II error. These results suggest that choice of assessment method, optimizing sample number and number of replicate estimates, and using a balanced experimental design are important criteria to consider to maximize the power of hypothesis tests for comparing treatments using disease severity estimates.

Design, construction and testing of a DC bioeffects test enclosure for small animals. Final report

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

Frazier, M J; Preache, M M

1980-11-01

This final report describes both the engineering development of a DC bioeffects test enclosure for small laboratory animals, and the biological protocol for the use of such enclosures in the testing of animals to determine possible biological effects of the environment associated with HVDC transmission lines. The test enclosure which has been designed is a modular unit, which will house up to eight rat-sized animals in individual compartments. Multiple test enclosures can be used to test larger numbers of animals. A prototype test enclosure has been fabricated and tested to characterize its electrical performance characteristics. The test enclosure provides amore » simulation of the dominant environment associated with HVDC transmission lines; namely, a static electric field and an ion current density. A biological experimental design has been developed for assessing the effects of the dominant components of the HVDC transmission line environment.« less

Does Film Affect Learning Engagement?: Historical Inquiry and the Document-Based Question in a Middle School Social Studies Classroom

ERIC Educational Resources Information Center

Paska, Lawrence M.

2010-01-01

This quasi-experimental study uses mixed methodologies to examine learning engagement on a social studies unit test based on primary and secondary sources (a "document-based question", or DBQ), to determine whether the use of film in a DBQ changes the nature of historical inquiry. The study was conducted in two Grade 7 classes taught by the same…

Experimental evaluation of thermal energy storage

NASA Technical Reports Server (NTRS)

Asbury, J. G.; Hersh, H. N.

1980-01-01

The technical performance of commercially available thermal energy storage (TES) residential heating units under severe weather conditions is discussed. The benefits and costs of TES to the user and utility companies were assessed. The TES issues, research and development needs, and barriers to commercialization were identified. The field tests which determined the performance characteristics for the TES are described and the TES systems, which included both ceramic and hydronic systems, are compared.

Krypton-85 Powered Lights for Airfield Application.

DTIC Science & Technology

1981-11-01

Department of Energy.(DOE), and eight lights were fabricated for testing by actual observation under airfield conditions. Light is produced in the units...concepts of radionuclide-powered lights, the R&D program carried out, and fabrication constraints involved in the production of the experimental...visible light has been known for many years. Early use of radium mixed with zinc sulfide phosphors provided self-illuminated clock dials. The military has

The effect of constructivist teaching strategies on science test scores of middle school students

NASA Astrophysics Data System (ADS)

Vaca, James L., Jr.

International studies show that the United States is lagging behind other industrialized countries in science proficiency. The studies revealed how American students showed little significant gain on standardized tests in science between 1995 and 2005. Little information is available regarding how reform in American teaching strategies in science could improve student performance on standardized testing. The purpose of this quasi-experimental quantitative study using a pretest/posttest control group design was to examine how the use of a hands-on, constructivist teaching approach with low achieving eighth grade science students affected student achievement on the 2007 Ohio Eighth Grade Science Achievement Test posttest (N = 76). The research question asked how using constructivist teaching strategies in the science classroom affected student performance on standardized tests. Two independent samples of 38 students each consisting of low achieving science students as identified by seventh grade science scores and scores on the Ohio Eighth Grade Science Half-Length Practice Test pretest were used. Four comparisons were made between the control group receiving traditional classroom instruction and the experimental group receiving constructivist instruction including: (a) pretest/posttest standard comparison, (b) comparison of the number of students who passed the posttest, (c) comparison of the six standards covered on the posttest, (d) posttest's sample means comparison. A Mann-Whitney U Test revealed that there was no significant difference between the independent sample distributions for the control group and the experimental group. These findings contribute to positive social change by investigating science teaching strategies that could be used in eighth grade science classes to improve student achievement in science.

A Computer Model of the Evaporator for the Development of an Automatic Control System

NASA Astrophysics Data System (ADS)

Kozin, K. A.; Efremov, E. V.; Kabrysheva, O. P.; Grachev, M. I.

2016-08-01

For the implementation of a closed nuclear fuel cycle it is necessary to carry out a series of experimental studies to justify the choice of technology. In addition, the operation of the radiochemical plant is impossible without high-quality automatic control systems. In the technologies of spent nuclear fuel reprocessing, the method of continuous evaporation is often used for a solution conditioning. Therefore, the effective continuous technological process will depend on the operation of the evaporation equipment. Its essential difference from similar devices is a small size. In this paper the method of mathematic simulation is applied for the investigation of one-effect evaporator with an external heating chamber. Detailed modelling is quite difficult because the phase equilibrium dynamics of the evaporation process is not described. Moreover, there is a relationship with the other process units. The results proved that the study subject is a MIMO plant, nonlinear over separate control channels and not selfbalancing. Adequacy was tested using the experimental data obtained at the laboratory evaporation unit.

Onsite 40-kilowatt fuel cell power plant manufacturing and field test program

NASA Technical Reports Server (NTRS)

1985-01-01

A joint Gas Research Institute and U.S. Department of Energy Program was initiated in 1982 to evaluate the use of fuel cell power systems for on-site energy service. Forty-six 40 kW fuel cell power plants were manufactured at the United Technologies Corporation facility in South Windsor, Connecticut, and are being delivered to host utilities and other program participants in the United States and Japan for field testing. The construction of the 46 fully-integrated power plants was completed in January 1985 within the constraints of the contract plan. The program has provided significant experience in the manufacture, acceptance testing, deployment, and support of on-site fuel cell systems. Initial field test results also show that these experimental power plants meet the performance and environmental requirements of a commercial specification. This Interim Report encompasses the design and manufacturing phases of the 40 kW Power Plant Manufacturing and Field Test program. The contract between UTC and NASA also provides UTC field engineering support to the host utilities, training programs and associated manuals for utility operating and maintenance personnel, spare parts support for a defined test period, and testing at UTC of a power plant made available from a preceding program phase. These activities are ongoing and will be reported subsequently.

Development of in situ product removal strategies in biocatalysis applying scaled-down unit operations.

PubMed

Heintz, Søren; Börner, Tim; Ringborg, Rolf H; Rehn, Gustav; Grey, Carl; Nordblad, Mathias; Krühne, Ulrich; Gernaey, Krist V; Adlercreutz, Patrick; Woodley, John M

2017-03-01

An experimental platform based on scaled-down unit operations combined in a plug-and-play manner enables easy and highly flexible testing of advanced biocatalytic process options such as in situ product removal (ISPR) process strategies. In such a platform, it is possible to compartmentalize different process steps while operating it as a combined system, giving the possibility to test and characterize the performance of novel process concepts and biocatalysts with minimal influence of inhibitory products. Here the capabilities of performing process development by applying scaled-down unit operations are highlighted through a case study investigating the asymmetric synthesis of 1-methyl-3-phenylpropylamine (MPPA) using ω-transaminase, an enzyme in the sub-family of amino transferases (ATAs). An on-line HPLC system was applied to avoid manual sample handling and to semi-automatically characterize ω-transaminases in a scaled-down packed-bed reactor (PBR) module, showing MPPA as a strong inhibitor. To overcome the inhibition, a two-step liquid-liquid extraction (LLE) ISPR concept was tested using scaled-down unit operations combined in a plug-and-play manner. Through the tested ISPR concept, it was possible to continuously feed the main substrate benzylacetone (BA) and extract the main product MPPA throughout the reaction, thereby overcoming the challenges of low substrate solubility and product inhibition. The tested ISPR concept achieved a product concentration of 26.5 g MPPA  · L -1 , a purity up to 70% g MPPA  · g tot -1 and a recovery in the range of 80% mol · mol -1 of MPPA in 20 h, with the possibility to increase the concentration, purity, and recovery further. Biotechnol. Bioeng. 2017;114: 600-609. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Quantitative structure-activity relationships for predicting potential ecological hazard of organic chemicals for use in regulatory risk assessments.

PubMed

Comber, Mike H I; Walker, John D; Watts, Chris; Hermens, Joop

2003-08-01

The use of quantitative structure-activity relationships (QSARs) for deriving the predicted no-effect concentration of discrete organic chemicals for the purposes of conducting a regulatory risk assessment in Europe and the United States is described. In the United States, under the Toxic Substances Control Act (TSCA), the TSCA Interagency Testing Committee and the U.S. Environmental Protection Agency (U.S. EPA) use SARs to estimate the hazards of existing and new chemicals. Within the Existing Substances Regulation in Europe, QSARs may be used for data evaluation, test strategy indications, and the identification and filling of data gaps. To illustrate where and when QSARs may be useful and when their use is more problematic, an example, methyl tertiary-butyl ether (MTBE), is given and the predicted and experimental data are compared. Improvements needed for new QSARs and tools for developing and using QSARs are discussed.

Chromatic dispersive confocal technology for intra-oral scanning: first in-vitro results

NASA Astrophysics Data System (ADS)

Ertl, T.; Zint, M.; Konz, A.; Brauer, E.; Hörhold, H.; Hibst, R.

2015-02-01

Various test objects, plaster models, partially equipped with extracted teeth and pig jaws representing various clinical situations of tooth preparations were used for in-vitro scanning tests with an experimental intra-oral scanning system based on chromatic-dispersive confocal technology. Scanning results were compared against data sets of the same object captured by an industrial μCT measuring system. Compared to μCT data an average error of 18 - 30 μm was achieved for a single tooth scan area and less than 40 to 60 μm error measured over the restoration + the neighbor teeth and pontic areas up to 7 units. Mean error for a full jaw is within 100 - 140 μm. The length error for a 3 - 4 unit bridge situation form contact point to contact point is below 100 μm and excellent interproximal surface coverage and prep margin clarity was achieved.

On the suitability of different representations of solid catalysts for combinatorial library design by genetic algorithms.

PubMed

Gobin, Oliver C; Schüth, Ferdi

2008-01-01

Genetic algorithms are widely used to solve and optimize combinatorial problems and are more often applied for library design in combinatorial chemistry. Because of their flexibility, however, their implementation can be challenging. In this study, the influence of the representation of solid catalysts on the performance of genetic algorithms was systematically investigated on the basis of a new, constrained, multiobjective, combinatorial test problem with properties common to problems in combinatorial materials science. Constraints were satisfied by penalty functions, repair algorithms, or special representations. The tests were performed using three state-of-the-art evolutionary multiobjective algorithms by performing 100 optimization runs for each algorithm and test case. Experimental data obtained during the optimization of a noble metal-free solid catalyst system active in the selective catalytic reduction of nitric oxide with propene was used to build up a predictive model to validate the results of the theoretical test problem. A significant influence of the representation on the optimization performance was observed. Binary encodings were found to be the preferred encoding in most of the cases, and depending on the experimental test unit, repair algorithms or penalty functions performed best.

Computational Homogenization of Mechanical Properties for Laminate Composites Reinforced with Thin Film Made of Carbon Nanotubes

NASA Astrophysics Data System (ADS)

El Moumen, A.; Tarfaoui, M.; Lafdi, K.

2018-06-01

Elastic properties of laminate composites based Carbone Nanotubes (CNTs), used in military applications, were estimated using homogenization techniques and compared to the experimental data. The composite consists of three phases: T300 6k carbon fibers fabric with 5HS (satin) weave, baseline pure Epoxy matrix and CNTs added with 0.5%, 1%, 2% and 4%. Two step homogenization methods based RVE model were employed. The objective of this paper is to determine the elastic properties of structure starting from the knowledge of those of constituents (CNTs, Epoxy and carbon fibers fabric). It is assumed that the composites have a geometric periodicity and the homogenization model can be represented by a representative volume element (RVE). For multi-scale analysis, finite element modeling of unit cell based two step homogenization method is used. The first step gives the properties of thin film made of epoxy and CNTs and the second is used for homogenization of laminate composite. The fabric unit cell is chosen using a set of microscopic observation and then identified by its ability to enclose the characteristic periodic repeat in the fabric weave. The unit cell model of 5-Harness satin weave fabric textile composite is identified for numerical approach and their dimensions are chosen based on some microstructural measurements. Finally, a good comparison was obtained between the predicted elastic properties using numerical homogenization approach and the obtained experimental data with experimental tests.

Computational Homogenization of Mechanical Properties for Laminate Composites Reinforced with Thin Film Made of Carbon Nanotubes

NASA Astrophysics Data System (ADS)

El Moumen, A.; Tarfaoui, M.; Lafdi, K.

2017-08-01

Elastic properties of laminate composites based Carbone Nanotubes (CNTs), used in military applications, were estimated using homogenization techniques and compared to the experimental data. The composite consists of three phases: T300 6k carbon fibers fabric with 5HS (satin) weave, baseline pure Epoxy matrix and CNTs added with 0.5%, 1%, 2% and 4%. Two step homogenization methods based RVE model were employed. The objective of this paper is to determine the elastic properties of structure starting from the knowledge of those of constituents (CNTs, Epoxy and carbon fibers fabric). It is assumed that the composites have a geometric periodicity and the homogenization model can be represented by a representative volume element (RVE). For multi-scale analysis, finite element modeling of unit cell based two step homogenization method is used. The first step gives the properties of thin film made of epoxy and CNTs and the second is used for homogenization of laminate composite. The fabric unit cell is chosen using a set of microscopic observation and then identified by its ability to enclose the characteristic periodic repeat in the fabric weave. The unit cell model of 5-Harness satin weave fabric textile composite is identified for numerical approach and their dimensions are chosen based on some microstructural measurements. Finally, a good comparison was obtained between the predicted elastic properties using numerical homogenization approach and the obtained experimental data with experimental tests.

Motor coordination and balance in rodents.

PubMed

Carter, R J; Morton, J; Dunnett, S B

2001-08-01

Measurement of motor coordination and balance can be used not only to assess the effect of drugs or other experimental manipulations on mice and rats, but also to characterize the motor phenotype of transgenic or knock-out animals. Three well established and widely used protocols for measuring motor coordination and balance in mice and rats (rotarod, beam walking and footprint analysis) are described in this unit. The tests can be used equally well for rats and mice, and have been used both for the phenotypic characterization of transgenic mice and for evaluating the effects of lesions and aging in rats. The protocols are described in the primary context of testing mice, but modifications of the test apparatus or variations in the test parameters for assessment of rats are noted.

Experimental evaluation of battery cells for space-based radar application

NASA Technical Reports Server (NTRS)

Maskell, Craig A.; Metcalfe, John R.

1994-01-01

A test program was conducted to characterize five space-quality nickel-hydrogen (NiH2) battery cells. A subset of those tests was also done on five commercial nickel-cadmium (NiCd) cells, for correlation to the characteristics of an Energy Storage Unit Simulator. The test program implemented the recommendations of a 1991 study, as reported to IECEC-92. The findings of the tests are summarized, and expected impacts on the performance of the electrical power system (EPS) of a large space-based radar (SBR) surveillance satellite are derived. The main characteristics examined and compared were terminal voltage (average and transient) and capacity through discharge, equivalent series resistance, derived inductance and capacitance, charge return efficiency, and inter-pulse charge effectiveness.

Material Control and Accounting (MC&A) System Upgrades and Performance Testing at the Russian Federal Nuclear Center-All-Russian Scientific Research Institute of Experimental Physics (RFNC-VNIIEF) VNIIEF)

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

Bushmelev, Vadim; Viktorov, Vladimir; Zhikharev, Stanislav

2008-01-01

The All-Russian Scientific Research Institute of Experimental Physics (VNIIEF), founded in 1946 at the historic village of Sarov, in Nizhniy Novgorod Oblast, is the largest nuclear research center in the Rosatom complex. In the framework of international collaboration, the United States (US) Department of Energy/National Nuclear Security Agency, in cooperation with US national laboratories, on the one hand, Rosatom and VNIIEF on the other hand, have focused their cooperative efforts to upgrade the existing material protection control and accountability system to prevent unauthorized access to the nuclear material. In this paper we will discuss the present status of material controlmore » and accounting (MC&A) system upgrades and the preliminary results from a pilot program on the MC&A system performance testing that was recently conducted at one technical area.« less

Experimental investigation of localized stress-induced leakage current distribution in gate dielectrics using array test circuit

NASA Astrophysics Data System (ADS)

Park, Hyeonwoo; Teramoto, Akinobu; Kuroda, Rihito; Suwa, Tomoyuki; Sugawa, Shigetoshi

2018-04-01

Localized stress-induced leakage current (SILC) has become a major problem in the reliability of flash memories. To reduce it, clarifying the SILC mechanism is important, and statistical measurement and analysis have to be carried out. In this study, we applied an array test circuit that can measure the SILC distribution of more than 80,000 nMOSFETs with various gate areas at a high speed (within 80 s) and a high accuracy (on the 10-17 A current order). The results clarified that the distributions of localized SILC in different gate areas follow a universal distribution assuming the same SILC defect density distribution per unit area, and the current of localized SILC defects does not scale down with the gate area. Moreover, the distribution of SILC defect density and its dependence on the oxide field for measurement (E OX-Measure) were experimentally determined for fabricated devices.

Yield of four Agaricus bisporus strains in three compost formulations and chemical composition analyses of the mushrooms

PubMed Central

de Andrade, Meire Cristina Nogueira; Zied, Diego Cunha; de Almeida Minhoni, Marli Teixeira; Kopytowski Filho, João

2008-01-01

Three compost formulations, consisting of two varieties of Cynodom dactylon (L.) Pers. (Coast-cross and Tyfton) and oat (Avena sativa) straw were tested for the cultivation of A. bisporus strains ABI-01/01, ABI-04/02, ABI-05/03, and ABI-06/04. A completely randomized experimental design in a factorial scheme was adopted, with 12 treatments (4 A. bisporus strains × 3 types of compost) and 8 replicates. Each experimental unit corresponded to one box containing 12 – 12.5 kg fresh wet compost. The data were submitted to analysis of variance and the means were compared by Tukey test. According to the results, productivity of mushrooms was influenced by strain and/or compost type. It was also verified that crude protein, ash, and crude fiber contents in the mushroom varied with A. bisporus strain and straw used in the formulation of the compost. PMID:24031271

Detection of antibodies against Theiler's murine encephalomyelitis virus GDVII strain in experimental guinea pigs.

PubMed

Häger, C; Glage, S; Held, N; Bleich, E M; Burghard, A; Mähler, M; Bleich, André

2016-10-01

A disease affecting guinea pigs called 'guinea pig lameness' characterized by clinical signs of depression, lameness of limbs, flaccid paralysis, weight loss and death within a few weeks was first described by Römer in 1911. After a research group in our facility kept laboratory guinea pigs from two different origins together in one room, lameness was observed in two animals. Further investigations revealed a serological immune response against Theiler's murine encephalomyelitis virus (TMEV; GDVII strain) in these animals. Histopathology of the lumbar spinal cord of these animals showed mononuclear cell infiltration and necrotic neurons in the anterior horn. Therefore, all guinea pigs from this contaminated animal unit, from other units in our facility, as well as from different European institutions and breeding centres were screened for antibodies directed against GDVII. Our investigations showed that approximately 80% of all guinea pigs from the contaminated animal unit were seropositive for GDVII, whereas animals from other separate units were completely negative. In addition, 43% of tested sera from the different European institutions and breeding centres contained antibodies against GDVII. The present data confirm that an unknown viral infection causes an immune response in experimental guinea pigs leading to seroconversion against GDVII and that guinea pigs from a commercial breeder are the source of the infection. © The Author(s) 2015.

Theoretical and experimental analysis of AlGaInP micro-LED array with square-circle anode

NASA Astrophysics Data System (ADS)

Tian, Chao; Wang, Weibiao; Liang, Jingqiu; Liang, Zhongzhu; Qin, Yuxin; Lv, Jinguang

2015-04-01

An array of 320 × 240 micro-light-emitting diodes (micro-LEDs) based on an AlGaInP epitaxial wafer and with a unit size of 100 µm×100 µm was designed and fabricated. The optimum width of the isolation groove between adjacent light-emitting units was determined based on a compromise between full isolation of each LED and maximization of the light emitting area, and was found to be 20 µm. The grooves were filled with a mixed Si granule-polyurethane composite medium, because this type of insulating material can reflect part of the emitted light from the sidewall to the window layer in each light-emitting unit, and could thus improve lighting output efficiency. The 10-µm-wide square-circle anode was designed to increase the light emitting area while simultaneously being simple to fabricate. The device current used was in the 0.42-1.06 mA range to guarantee internal quantum efficiency of more than 85%, with a corresponding voltage range of 2-2.3 V. The layered temperature distribution in a single unit was simulated under a drive voltage of 2.2 V, and the maximum device temperature was 341 K. The micro-opto-electro-mechanical systems (MOEMS) technology-based fabrication process, experimental images of the device and device test results are presented here.

Analysis of the mechanical behavior of a titanium scaffold with a repeating unit-cell substructure.

PubMed

Ryan, Garrett; McGarry, Patrick; Pandit, Abhay; Apatsidis, Dimitrios

2009-08-01

Titanium scaffolds with controlled microarchitecture have been developed for load bearing orthopedic applications. The controlled microarchitecture refers to a repeating array of unit-cells, composed of sintered titanium powder, which make up the scaffold structure. The objective of this current research was to characterize the mechanical performance of three scaffolds with increasing porosity, using finite element analysis (FEA) and to compare the results with experimental data. Scaffolds were scanned using microcomputed tomography and FEA models were generated from the resulting computer models. Macroscale and unit-cell models of the scaffolds were created. The material properties of the sintered titanium powders were first evaluated in mechanical tests and the data used in the FEA. The macroscale and unit-cell FEA models proved to be a good predictor of Young's modulus and yield strength. Although macroscale models showed similar failure patterns and an expected trend in UCS, strain at UCS did not compare well with experimental data. Since a rapid prototyping method was used to create the scaffolds, the original CAD geometries of the scaffold were also evaluated using FEA but they did not reflect the mechanical properties of the physical scaffolds. This indicates that at present, determining the actual geometry of the scaffold through computed tomography imaging is important. Finally, a fatigue analysis was performed on the scaffold to simulate the loading conditions it would experience as a spinal interbody fusion device.

Theoretical and experimental analysis of AlGaInP micro-LED array with square-circle anode

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

Tian, Chao; University of Chinese Academy of Sciences, Beijing 100049; Wang, Weibiao, E-mail: wangwbcn@163.com

An array of 320 × 240 micro-light-emitting diodes (micro-LEDs) based on an AlGaInP epitaxial wafer and with a unit size of 100 µm×100 µm was designed and fabricated. The optimum width of the isolation groove between adjacent light-emitting units was determined based on a compromise between full isolation of each LED and maximization of the light emitting area, and was found to be 20 µm. The grooves were filled with a mixed Si granule-polyurethane composite medium, because this type of insulating material can reflect part of the emitted light from the sidewall to the window layer in each light-emitting unit,more » and could thus improve lighting output efficiency. The 10-µm-wide square-circle anode was designed to increase the light emitting area while simultaneously being simple to fabricate. The device current used was in the 0.42–1.06 mA range to guarantee internal quantum efficiency of more than 85%, with a corresponding voltage range of 2–2.3 V. The layered temperature distribution in a single unit was simulated under a drive voltage of 2.2 V, and the maximum device temperature was 341 K. The micro-opto-electro-mechanical systems (MOEMS) technology-based fabrication process, experimental images of the device and device test results are presented here.« less

Design of Magnetic Shielding and Field Coils for a TES X-Ray Microcalorimeter Test Platform

NASA Technical Reports Server (NTRS)

Miniussi, Antoine R.; Adams, Joseph S.; Bandler, Simon R.; Chervenak, James A.; Datesman, Aaron M.; Doriese, William B.; Eckart, Megan E.; Finkbeiner, Fred M.; Kelley, Richard L.; Kilbourne, Caroline A.;

Mechanisms of Injury and Countermeasures for EVA Associated Upper Extremity Medical Issues: Extended Vent Tube Study

NASA Technical Reports Server (NTRS)

Jones, Jeff; Hoffman, Ron; Harvey, Craig; Bowen, C. K.; Hudy, C. E.; Tuxhorn, Jennifer; Gernhardt, Mike; Scheuring, Richard A.

2007-01-01

The goal of this study is to determine the role that moisture plays in the injury to the fingers and fingernails during EVA training operations in the Neutral Buoyancy Laboratory. Current Extravehicular Mobility Unit (EMU, with a PLSS) as configured in the NBL was used for all testing and a vent tube was extended down a single arm of the crewmember during the test; vent tube was moved between left and right arm to serve as experimental condition being investigated and the other arm served as control condition.

Combined experimental and numerical evaluation of a prototype nano-PCM enhanced wallboard

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

Biswas, Kaushik; LuPh.D., Jue; Soroushian, Parviz

2014-01-01

In the United States, forty-eight (48) percent of the residential end-use energy consumption is spent on space heating and air conditioning. Reducing envelope-generated heating and cooling loads through application of phase change material (PCM)-enhanced building envelopes can facilitate maximizing the energy efficiency of buildings. Combined experimental testing and numerical modeling of PCM-enhanced envelope components are two important aspects of the evaluation of their energy benefits. An innovative phase change material (nano-PCM) was developed with PCM encapsulated with expanded graphite (interconnected) nanosheets, which is highly conductive for enhanced thermal storage and energy distribution, and is shape-stable for convenient incorporation into lightweightmore » building components. A wall with cellulose cavity insulation and prototype PCM-enhanced interior wallboards was built and tested in a natural exposure test (NET) facility in a hot-humid climate location. The test wall contained PCM wallboards and regular gypsum wallboard, for a side-by-side annual comparison study. Further, numerical modeling of the walls containing the nano-PCM wallboard was performed to determine its actual impact on wall-generated heating and cooling loads. The model was first validated using experimental data, and then used for annual simulations using Typical Meteorological Year (TMY3) weather data. This article presents the measured performance and numerical analysis evaluating the energy-saving potential of the nano-PCM-enhanced wallboard.« less

Effect of a toothpaste containing triclosan, cetylpyridinium chloride, and essential oils on gingival status in schoolchildren: a randomized clinical pilot study.

PubMed

Cagetti, Maria Grazia; Strohmenger, Laura; Basile, Valentina; Abati, Silvio; Mastroberardino, Stefano; Campus, Guglielmo

2015-05-01

This randomized double-blind in vivo pilot study has evaluated the effects of a toothpaste containing fluoride (control) versus toothpaste containing fluoride, triclosan, cetylpyridinium chloride and essential oils (experimental) in controlling supragingival dental plaque and bleeding on probing in a sample of healthy schoolchildren. In total, 48 children (8 to 10 years) were selected and randomly divided into two groups (experimental and control), using the two different toothpastes twice a day for 2 minutes each for a 4-week period. The investigation included an evaluation of plaque quantity, using the Turesky modified Quigley-Hein method, and bleeding on probing that was recorded dichotomously. The unit of analysis was set at the gingival site level. Plaque Index and bleeding on probing were analyzed using distribution tables and chi-square test. A generalized estimating equation was used to estimate the parameters of a generalized linear model with a possible unknown correlation between outcomes. In total, 40 schoolchildren completed the trial. Considering each group separately, a statistically significant difference in plaque scores was recorded for both treatments (z-test = 9.23, P < .01 for the experimental toothpaste; and z-test = 7.47, P < .01 for the control toothpaste). Nevertheless, the effect over time was higher for the experimental toothpaste than for the control one (3.38 vs 1.96). No statistically significant results were observed regarding bleeding on probing. The 4-week use of the experimental toothpaste seems to produce higher plaque reduction compared to fluoridated toothpaste without other antibacterial ingredients. This finding has to be confirmed in a larger study.

The difference between “equivalent” and “not different”

DOE PAGES

Anderson-Cook, Christine M.; Borror, Connie M.

2015-10-27

Often, experimenters wish to establish that populations of units can be considered equivalent to each other, in order to leverage improved knowledge about one population for characterizing the new population, or to establish the comparability of items. Equivalence tests have existed for many years, but their use in industry seems to have been largely restricted to biomedical applications, such as for assessing the equivalence of two drugs or protocols. We present the fundamentals of equivalence tests, compare them to traditional two-sample and ANOVA tests that are better suited to establishing differences in populations, and propose the use of a graphicalmore » summary to compare p-values across different thresholds of practically important differences.« less

Integrated control and health monitoring capacitive displacement sensor development task. Orbit transfer rocket engine technology program

NASA Technical Reports Server (NTRS)

Collamore, Frank N.

1989-01-01

The development of a miniature multifunction turbomachinery shaft displacement sensor using state-of-the-art non-contract capacitive sensing technology is described. Axial displacement, radial displacement, and speed are sensed using a single probe within the envelope normally required for a single function. A survey of displacement sensing technology is summarized including inductive, capacitive, optical and ultrasonic techniques. The design and operation of an experimental triple function sensor is described. Test results are included showing calibration tests and simultaneous dynamic testing of multiple functions. Recommendations for design changes are made to improve low temperature performance, reliability, and for design of a flight type signal conditioning unit.

The effect of aromatherapy on haemodialysis patients' pruritus.

PubMed

Cürcani, Mehtap; Tan, Mehtap

2014-12-01

To determine the effect of aromatherapy on pruritus observed in haemodialysis patients. Although the prevalence of pruritus in kidney failure has decreased in the recent years, pruritus is a difficult and serious problem which concerns the majority of haemodialysis patents and is hard to cure. A prospective, pretest-post-test quasi-experimental design was used. The research is quasi-experimental clinical trial conducted as pretest and post-test with control groups between January 2011-April 2012, in haemodialysis units of hospitals in Erzurum. The collection of the data is achieved using a questionnaire to detect the patients' individual and pruritus score scale and to clarify certain laboratory parameters regarding the pruritus. Chi-square analysis and t-test are used for the analysis of data. The experimental group's mean post-test pruritus scores (7·20 ± 3·14) were found to be lower than that of control group patients (10·00 ± 2·47), and a highly significant difference was found between the groups (p < 0·001). In the between-groups comparisons of experimental and control group's laboratory parameters, the experimental group's post-test blood urea nitrogen levels (118·26 ± 36·76) were found to be lower than that of control group patients (138·80 ± 48·69), and the between-groups difference was found to be statistically significant (p < 0·05). The results demonstrate that aromatherapy was found to decrease the pruritus problem of haemodialyses patients and led to positive changes in some laboratory parameters related to pruritus. One of the roles of health professionals is to advise individuals, who are living on this problem, using the nonpharmacological methods in checking the itching. By preventing or reducing uraemic pruritus, aromatherapy may also improve quality of life in this patient group. © 2014 John Wiley & Sons Ltd.

HIFIRE Flight 2 Overview and Status Update 2011

NASA Technical Reports Server (NTRS)

Jackson, Kevin R.; Gruber, Mark R.; Buccellato, Salvatore

2011-01-01

A collaborative international effort, the Hypersonic International Flight Research Experimentation (HIFiRE) Program aims to study basic hypersonic phenomena through flight experimentation. HIFiRE Flight 2 teams the United States Air Force Research Lab (AFRL), NASA, and the Australian Defence Science and Technology Organisation (DSTO). Flight 2 will develop an alternative test technique for acquiring high enthalpy scramjet flight test data, allowing exploration of accelerating hydrocarbon-fueled scramjet performance and dual-to-scram mode transition up to and beyond Mach 8 flight. The generic scramjet flowpath is research quality and the test fuel is a simple surrogate for an endothermically cracked liquid hydrocarbon fuel. HIFiRE Flight 2 will be a first of its kind in contribution to scramjets. The HIFiRE program builds upon the HyShot and HYCAUSE programs and aims to leverage the low-cost flight test technique developed in those programs. It will explore suppressed trajectories of a sounding rocket propelled test article and their utility in studying ramjet-scramjet mode transition and flame extinction limits research. This paper describes the overall scramjet flight test experiment mission goals and objectives, flight test approach and strategy, ground test and analysis summary, development status and project schedule. A successful launch and operation will present to the scramjet community valuable flight test data in addition to a new tool, and vehicle, with which to explore high enthalpy scramjet technologies.

Develop and test fuel cell powered on-site integrated total energy system

NASA Technical Reports Server (NTRS)

Kaufman, A.; Johnson, G. K.

1982-01-01

Satisfactory performance is reported for the first 12-cell sub-stack of the 5 kW rebuild using improved ABA reactant distribution plates. Construction and test results are described for the first full-sized single-cell test (0.33 m x 0.56 m). Test duration was 450 hours. Plans are outlined for construction and testing of two methanol reformer units based on commercially-available shell-and-tube heat exchangers. A 5 kW-equivalent precursor and a 50 kW-equivalent prototype will be built. Supporting design and single-tube experimental data are presented. Stack support efforts are summarized on corrosion currents of graphite materials and acid-management of single-cell test facilities. Comparative properties are summarized for the two methanol/steam reforming catalysts evauated under Task V (now completed); T2107RS and C70-2RS.

Colloidal Material Box: In-situ Observations of Colloidal Self-Assembly and Liquid Crystal Phase Transitions in Microgravity

NASA Astrophysics Data System (ADS)

Li, WeiBin; Lan, Ding; Sun, ZhiBin; Geng, BaoMing; Wang, XiaoQing; Tian, WeiQian; Zhai, GuangJie; Wang, YuRen

2016-05-01

To study the self-assembly behavior of colloidal spheres in the solid/liquid interface and elucidate the mechanism of liquid crystal phase transition under microgravity, a Colloidal Material Box (CMB) was designed which consists of three modules: (i) colloidal evaporation experimental module, made up of a sample management unit, an injection management unit and an optical observation unit; (ii) liquid crystal phase transition experimental module, including a sample management unit and an optical observation unit; (iii) electronic control module. The following two experimental plans will be performed inside the CMB aboard the SJ-10 satellite in space. (i) Self-assembly of colloidal spheres (with and without Au shell) induced by droplet evaporation, allowing observation of the dynamic process of the colloidal spheres within the droplet and the change of the droplet outer profile during evaporation; (ii) Phase behavior of Mg2Al LDHs suspensions in microgravity. The experimental results will be the first experimental observations of depositing ordered colloidal crystals and their self-assembly behavior under microgravity, and will illustrate the influence of gravity on liquid crystal phase transition.

Energy consumption analysis and simulation of waste heat recovery technology of ceramic rotary kiln

NASA Astrophysics Data System (ADS)

Chen, Zhiguang; Zhou, Yu; Qin, Chaokui; Zhang, Xuemei

2018-03-01

Ceramsite is widely used in the construction industry, insulation works and oil industry in China, and the manufacture equipment is mainly industrial kiln. In this paper, energy consumption analysis had been carried out through experimental test of a Ceramsite kiln in Henan province. Results showed that the discharge temperature of Ceramsite was about 1393K, and the waste heat accounted for 22.1% of the total energy consumption. A structure of cyclone preheater which recovered waste heat of the high temperature Ceramsite by blast cooling was designed. Then, using Fluent software, performance of the unit was simulated. The minimum temperature that Ceramsite could reach, heat dissipating capacity of Ceramsite, temperature at air outlet, wall temperature of the unit and pressure loss were analyzed. Performance of the designed unit under different inlet velocity was analyzed as well.

Building NYX [Engineering Materials

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

Not Available

1988-01-01

From April, 1951, to August 1954, New York Shipbuilding corporation carried out a subcontract with E.I. du Pont de Nemours company that was without parallel in the shipyard's history. The work, designated the NYX Project'' for reasons of security, which was vital to the operations of the Savannah River Plant, Aiken, S.C., which was then being designed and constructed by du Pont for the Atomic Energy Commission. It consisted of three broad parts: Development and experimental work; fabrication and testing of a prototype unit; and fabrication of production units. Five production units were ultimately built, one of them converted frommore » the prototype. All were fabricated from stainless steel, and involved welding techniques, control of thermal distortion and tolerances never previously attempted on assemblies of comparable size. This report provides engineering drawings for this project.« less

Building NYX [Engineering Materials

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

Not Available

1988-12-31

From April, 1951, to August 1954, New York Shipbuilding corporation carried out a subcontract with E.I. du Pont de Nemours & company that was without parallel in the shipyard`s history. The work, designated the ``NYX Project`` for reasons of security, which was vital to the operations of the Savannah River Plant, Aiken, S.C., which was then being designed and constructed by du Pont for the Atomic Energy Commission. It consisted of three broad parts: Development and experimental work; fabrication and testing of a prototype unit; and fabrication of production units. Five production units were ultimately built, one of them convertedmore » from the prototype. All were fabricated from stainless steel, and involved welding techniques, control of thermal distortion and tolerances never previously attempted on assemblies of comparable size. This report provides engineering drawings for this project.« less

Teaching Semantic Radicals Facilitates Inferring New Character Meaning in Sentence Reading for Nonnative Chinese Speakers

PubMed Central

Nguyen, Thi Phuong; Zhang, Jie; Li, Hong; Wu, Xinchun; Cheng, Yahua

2017-01-01

This study investigates the effects of teaching semantic radicals in inferring the meanings of unfamiliar characters among nonnative Chinese speakers. A total of 54 undergraduates majoring in Chinese Language from a university in Hanoi, Vietnam, who had 1 year of learning experience in Chinese were assigned to two experimental groups that received instructional intervention, called “old-for-new” semantic radical teaching, through two counterbalanced sets of semantic radicals, with one control group. All of the students completed pre- and post-tests of a sentence cloze task where they were required to choose an appropriate character that fit the sentence context among four options. The four options shared the same phonetic radicals but had different semantic radicals. The results showed that the pre-test and post-test score increases were significant for the experimental groups, but not for the control group. Most importantly, the experimental groups successfully transferred the semantic radical strategy to figure out the meanings of unfamiliar characters containing semantic radicals that had not been taught. The results demonstrate the effectiveness of teaching semantic radicals for lexical inference in sentence reading for nonnative speakers, and highlight the ability of transfer learning to acquire semantic categories of sub-lexical units (semantic radicals) in Chinese characters among foreign language learners. PMID:29109694

Effects of a needs-based education programme for family carers with a relative in an intensive care unit: a quasi-experimental study.

PubMed

Chien, Wai-Tong; Chiu, Y L; Lam, Lai-Wah; Ip, Wan-Yim

2006-01-01

Critical illness and subsequent hospitalisation of a relative to an intensive care unit (ICU) can result in many physiological and psychosocial problems for patients and their family members. Caring for the anxiety and frustration of these families is an integral part of critical care nursing. The purpose of this study was to examine the effect of a needs-based education programme provided within the first 3 days of patients' hospitalisation, on the anxiety levels and satisfaction of psychosocial needs of their families. This was a quasi-experimental study with pre- and post-test design. A convenience sample was recruited over a period of three months, consisting of one primary family carer of each critically ill patient who had been admitted to an ICU in Hong Kong. Conducted by an ICU nurse specially assigned for the purpose, family carers in the experimental group (n=34) received an individual education programme based on the results of a literature review and an individual family needs assessment carried out at the time of patient admission, using the Critical Care Family Needs Inventory. The subjects in the control group (n=32) received the usual orientation and explanation given by the ICU nurses. Anxiety and need satisfaction were measured in the two groups at pre- and post-test and their mean scores were compared. Of the ten most important statements identified by the family carers in the two groups, the statements regarding the needs for information and assurance were found to predominate. After the needs-based intervention, the experimental group reported significantly lower levels of anxiety and higher levels of satisfaction of family needs than the control group at the post-test. The findings support the effectiveness of providing families of newly admitted critically ill patients, with a needs-based educational intervention to allay anxiety and satisfy immediate psychosocial needs. The formulation of a family education programme should be based on the results of a needs assessment, in order to meet family carers' individual needs.

The effect of the 4MAT learning model on the achievement and motivation of 7th grade students on the subject of particulate nature of matter and an examination of student opinions on the model

NASA Astrophysics Data System (ADS)

Aktas, İdris; Bılgın, İbrahim

2015-01-01

Background:Many researchers agree that students, especially primary students, have learning difficulties on the 'Particulate Nature of Matter' unit. One reason for this difficulty is not considering individual differences for teaching science. In 4MAT model learning, environment is arranged according to individual differences. Purpose:The purpose of this study is to examine (1) the effects of the 4MAT learning model on the7th grade students' academic achievement and motivation on the 'Particulate Nature of Matter' unit and (2) identify student opinions on the 4MAT model. Sample:The sample consists of 235 students (115 experimental, 120 control) in Turkey. Design and methods:Experimental groups were instructed with the 4MAT model while control groups were instructed with a traditional method. Achievement Test (AchToM) and Motivation Scale (MotScl) were administered to students as pre- and post-tests. Moreover, the opinions of students in the experimental groups on the 4MAT model were ascertained through open-ended questions after the application. Results:According to independent t-test results, statistical difference in favour of the experimental groups was detected between the post-AchToM (ES = 1.43; p < .0001) and post-MotScl (ES = 0.32; p < .05) scores. According to data obtained from the questionnaire, the application of the 4MAT model increases student motivation and participation in the lesson, lessons are more amusing and enjoyable, and the self-confidence of the students increases. Besides these positive opinions, however, a few students stated that the method took too much time, they were not motivated and it did not help them in understanding the subject. Conclusions:The 4MAT model is more effective than traditional method in terms of increasing achievement and motivation. The model takes all learners into account. Thus, the teacher or educator should use the 4MAT model to ensure all students' learning in their classroom.

Experimental digester facility modifications and digester gas upgrading research

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

Srivastava, V.J.; Biljetina, R.; Akin, C.

1989-01-01

The Institute of Gas Technology (IGT) has been participating in an experimental program at the Community Waste Research Facility (CWRF) located at the Walt Disney World Resort Complex, Orlando, Florida. Four institutions have formed a team to provide solutions to community waste treatment and disposal programs. Of primary importance to this research effort is the implementation of low-cost, energy-efficient waste treatment and recovery technologies and the net production of energy (methane) from biomass and waste resources. The production of methane is being studied in a novel, high-rate digester. During 1988, we were responsible for modifying the Experimental Test Unit (ETU)more » to permit dry solids feeding of refuse-derived fuel (RDF) and for conducting bench-scale experiments to evaluate techniques for efficient removal of carbon dioxide produced during anaerobic digestion.« less

Hovering Dual-Spin Vehicle Groundwork for Bias Momentum Sizing Validation Experiment

NASA Technical Reports Server (NTRS)

Rothhaar, Paul M.; Moerder, Daniel D.; Lim, Kyong B.

2008-01-01

Angular bias momentum offers significant stability augmentation for hovering flight vehicles. The reliance of the vehicle on thrust vectoring for agility and disturbance rejection is greatly reduced with significant levels of stored angular momentum in the system. A methodical procedure for bias momentum sizing has been developed in previous studies. This current study provides groundwork for experimental validation of that method using an experimental vehicle called the Dual-Spin Test Device, a thrust-levitated platform. Using measured data the vehicle's thrust vectoring units are modeled and a gust environment is designed and characterized. Control design is discussed. Preliminary experimental results of the vehicle constrained to three rotational degrees of freedom are compared to simulation for a case containing no bias momentum to validate the simulation. A simulation of a bias momentum dominant case is presented.

Experimental Progress Toward Detection and Identification of Electromagnetically Complex Structures

DTIC Science & Technology

2008-12-01

M. Jaenisch and J. W. Handley Amtec Corporation Huntsville, Alabama 35816-3429 T.A. Baginski and A.S. Hodel Auburn University Auburn, Alabama...ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Amtec ...transmitter power is relatively low; consequently, our target is entirely above ground for now. Measurements are conducted at the Amtec Outdoor Test

Coexistence of twitch potentiation and tetanic force decline in rat hindlimb muscle

NASA Technical Reports Server (NTRS)

Rankin, Lucinda L.; Enoka, Roger M.; Volz, Kathryn A.; Stuart, Douglas G.

1988-01-01

The effect of whole-muscle fatigue on the isometric twitch was investigated in various hindlimb muscles of anesthetized rats, using an experimental protocol designed to assess the levels of fatigability in motor units. The results of EMG and force measurements revealed the existence of a linear relationship between fatigability and the magnitude of the twitch force following the fatigue test in both soleus and extensor digitorum longus muscles.

From enumeration districts to output areas: experiments in the automated creation of a census output geography.

PubMed

Martin, D

1997-01-01

This article briefly reviews the advantages of using separate geographies for census enumeration and output, and explains how a geographical information system is being used for the planning of enumeration districts for the 1997 Census Test. Experimental work is described which offers the potential to automatically create a new output geography, formed from aggregations of unit postcodes, and which offers control over output area population and boundaries.

Interruption of Neural Function.

DTIC Science & Technology

1987-05-01

applcbse) University of Colorado I Be. ADDRESS (City. Stele and ZIP Code) 10. SOURCE OF FUNDING NOS. Campus Box B-19 PROGRAM PROJECT TASK WORK UNIT Boulder...rectification, frequency-sensitive phenomena, safety, and some effects on bio - logical systems," invited review, Charles Polk, Ed., CRC Handbook of Biological...experimental test", Mathematical Bio - Sciences, Vol. 29, pp. 235-253, 1978. [131 Kuf1er. S. WV., J. G. Nicholls, and A. R. Martin, "From Nettron to Brain

International Space Station (ISS)

NASA Image and Video Library

1998-01-01

This artist's concept depicts the completely assembled International Space Station (ISS) passing over the Straits of Gibraltar and the Mediterranean Sea. As a gateway to permanent human presence in space, the Space Station Program is to expand knowledge benefiting all people and nations. The ISS is a multidisciplinary laboratory, technology test bed, and observatory that will provide unprecedented undertakings in scientific, technological, and international experimentation. Experiments to be conducted in the ISS include: microgravity research, Earth science, space science, life sciences, space product development, and engineering research and technology. The sixteen countries participating the ISS are: United States, Russian Federation, Canada, Japan, United Kingdom, Germany, Italy, France, Norway, Netherlands, Belgium, Spain, Denmark, Sweden, Switzerland, and Brazil.

Fractionated analysis of paired-electrode nerve recordings.

PubMed

Fiore, Lorenzo; Lorenzetti, Walter; Ratti, Giovannino; Geppetti, Laura

2003-12-30

Multi-unit activity recorded from two electrodes positioned at a distance on a nerve may be analysed by cross-correlation, but units similar in direction and velocity of propagation cannot be distinguished and separately evaluated by this method. To overcome this limit, we added two features, represented by the impulse amplitudes of the paired recordings, to the dimension given by the impulse delay. The analysis was fractionated according to the new dimensions. In experimental recordings from the locomotor appendage of the lobster Homarus americanus, the fractionated analysis proved capable of identifying the contributions of single active units, even if these were superimposed and indiscernible in the global cross-correlation histogram. Up to 5 motor and 10 sensory units could be identified. The shape of the paired impulses was evaluated by an averaging procedure. Analogous evaluations on simulated recordings made it possible to estimate the influences exerted on performance by variations in noise level and in the number and firing rate of active units. The global signal could be resolved into single units even under the worst conditions. Accuracy in evaluating the amount of unit activity varied, exceeding 90% in about half of the cases tested; a similar performance was attained by evaluation of the impulse shapes.

Opposed piston linear compressor driven two-stage Stirling Cryocooler for cooling of IR sensors in space application

NASA Astrophysics Data System (ADS)

Bhojwani, Virendra; Inamdar, Asif; Lele, Mandar; Tendolkar, Mandar; Atrey, Milind; Bapat, Shridhar; Narayankhedkar, Kisan

2017-04-01

A two-stage Stirling Cryocooler has been developed and tested for cooling IR sensors in space application. The concept uses an opposed piston linear compressor to drive the two-stage Stirling expander. The configuration used a moving coil linear motor for the compressor as well as for the expander unit. Electrical phase difference of 80 degrees was maintained between the voltage waveforms supplied to the compressor motor and expander motor. The piston and displacer surface were coated with Rulon an anti-friction material to ensure oil less operation of the unit. The present article discusses analysis results, features of the cryocooler and experimental tests conducted on the developed unit. The two-stages of Cryo-cylinder and the expander units were manufactured from a single piece to ensure precise alignment between the two-stages. Flexure bearings were used to suspend the piston and displacer about its mean position. The objective of the work was to develop a two-stage Stirling cryocooler with 2 W at 120 K and 0.5 W at 60 K cooling capacity for the two-stages and input power of less than 120 W. The Cryocooler achieved a minimum temperature of 40.7 K at stage 2.

Cortical modulation of the nucleus of the optic tract in the rabbit.

PubMed

Pettorossi, V E; Troiani, D

1983-09-01

We analyzed in rabbits the relationships between the temporooccipital nystagmogenic cortex (NGC)--the region sited at the border between cortical areas 17, 21, and 22--and the nucleus of the optic tract (NOT). Two experimental approaches were used: (a) eye movement analysis before and after electrolytic lesion of the NOT region provided an indication of the importance of the NOT for the interaction between the ocular nystagmus elicited by natural optokinetic stimulation (OKN) and the nystagmus evoked by electrical stimulation of the nystagmogenic area; (b) NOT direction-selective and velocity-sensitive units were tested with single shock or repetitive electrical stimulation of the nystagmogenic region. Single-shock stimulation evoked single or multiple spikes in 50% of NOT units analyzed and repetitive stimuli induced prolonged facilitation and inhibitory rebounds in 70% of the units tested. Comparison of orthodromic activation latencies of the NOT cells (3.2 and 6.1 ms) after cortical stimulation and of antidromic activation latencies of cortical nystagmogenic units (2.6 ms) after NOT shocks, suggested monosynaptic as well as polysynaptic connections between the temporooccipital cortex and the NOT. The existence of such cortical-NOT linkage indicates that the NOT is intercalated between the cortex and the oculomotor centers and represents the most probable site of interaction of the cortical nystagmus pathway with the optokinetic reflex arc.

Different leachate phytotreatment systems using sunflowers.

PubMed

Garbo, Francesco; Lavagnolo, Maria Cristina; Malagoli, Mario; Schiavon, Michela; Cossu, Raffaello

2017-01-01

The use of energy crops in the treatment of wastewaters is of increasing interest, particularly in view of the widespread scarcity of water in many countries and the possibility of obtaining renewable fuels of vegetable origin. The aim of this study was to evaluate the feasibility of landfill leachate phytotreatment using sunflowers, particularly as seeds from this crop are suitable for use in biodiesel production. Two different irrigation systems were tested: vertical flow and horizontal subsurface flow, with or without effluent recirculation. Plants were grown in 130L rectangular tanks placed in a special climatic chamber. Leachate irrigated units were submitted to increasing nitrogen concentrations up to 372mgN/L. Leachate was successfully tested as an alternative fertilizer for plants and was not found to inhibit biomass development. The experiment revealed good removal efficiencies for COD (η>50%) up until flowering, while phosphorous removal invariably exceeded 60%. Nitrogen removal rates decreased over time in all experimental units, particularly in vertical flow tanks. In general, horizontal flow units showed the best performances in terms of contaminant removal capacity; the effluent recirculation procedure did not improve performance. Significant evapo-transpiration was observed, particularly in vertical flow units, promoting removal of up to 80% of the inlet irrigation volume. Copyright © 2016 Elsevier Ltd. All rights reserved.

Pharmaceutics, Drug Delivery and Pharmaceutical Technology: A New Test Unit for Disintegration End-Point Determination of Orodispersible Films.

PubMed

Low, Ariana; Kok, Si Ling; Khong, Yuetmei; Chan, Sui Yung; Gokhale, Rajeev

2015-11-01

No standard time or pharmacopoeia disintegration test method for orodispersible films (ODFs) exists. The USP disintegration test for tablets and capsules poses significant challenges for end-point determination when used for ODFs. We tested a newly developed disintegration test unit (DTU) against the USP disintegration test. The DTU is an accessory to the USP disintegration apparatus. It holds the ODF in a horizontal position, allowing top-view of the ODF during testing. A Gauge R&R study was conducted to assign relative contributions of the total variability from the operator, sample or the experimental set-up. Precision was compared using commercial ODF products in different media. Agreement between the two measurement methods was analysed. The DTU showed improved repeatability and reproducibility compared to the USP disintegration system with tighter standard deviations regardless of operator or medium. There is good agreement between the two methods, with the USP disintegration test giving generally longer disintegration times possibly due to difficulty in end-point determination. The DTU provided clear end-point determination and is suitable for quality control of ODFs during product developmental stage or manufacturing. This may facilitate the development of a standardized methodology for disintegration time determination of ODFs. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 104:3893-3903, 2015. Copyright © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

A randomized controlled trial of an intervention program to Brazilian mothers who use corporal punishment.

PubMed

Santini, Paolla Magioni; Williams, Lucia C A

2017-09-01

This study evaluated a positive parenting program to Brazilian mothers who used corporal punishment with their children. The intervention was conducted in four agencies serving vulnerable children, and at a home replica laboratory at the University. Mothers who admitted using corporal punishment were randomly assigned between experimental (n=20) and control group (n=20). The program consisted of 12 individual sessions using one unit from Projeto Parceria (Partnership Project), with specific guidelines and materials on positive parenting, followed by observational sessions of mother-child interaction with live coaching and a video feedback session in the lab. The study used an equivalent group experimental design with pre/post-test and follow-up, in randomized controlled trials. Measures involved: Initial Interview; Strengths and Difficulties Questionnaire (SDQ) - parent and child versions; Beck Depression Inventory (BDI); observational sessions with a protocol; and a Program Evaluation by participants. Analysis of mixed models for repeated measures revealed significant positive effects on the BDI and SDQ total scores, as well as less Conduct problems and Hyperactivity in SDQ measures from the experimental group mothers, comparing pre with post-test. Observational data also indicated significant improvement in positive interaction from the experimental group mothers at post-test, in comparison with controls. No significant results were found, however, in children's observational measures. Limitations of the study involved using a restricted sample, among others. Implications for future research are suggested. Copyright © 2017 Elsevier Ltd. All rights reserved.

Statistical analysis of early failures in electromigration

NASA Astrophysics Data System (ADS)

Gall, M.; Capasso, C.; Jawarani, D.; Hernandez, R.; Kawasaki, H.; Ho, P. S.

2001-07-01

The detection of early failures in electromigration (EM) and the complicated statistical nature of this important reliability phenomenon have been difficult issues to treat in the past. A satisfactory experimental approach for the detection and the statistical analysis of early failures has not yet been established. This is mainly due to the rare occurrence of early failures and difficulties in testing of large sample populations. Furthermore, experimental data on the EM behavior as a function of varying number of failure links are scarce. In this study, a technique utilizing large interconnect arrays in conjunction with the well-known Wheatstone Bridge is presented. Three types of structures with a varying number of Ti/TiN/Al(Cu)/TiN-based interconnects were used, starting from a small unit of five lines in parallel. A serial arrangement of this unit enabled testing of interconnect arrays encompassing 480 possible failure links. In addition, a Wheatstone Bridge-type wiring using four large arrays in each device enabled simultaneous testing of 1920 interconnects. In conjunction with a statistical deconvolution to the single interconnect level, the results indicate that the electromigration failure mechanism studied here follows perfect lognormal behavior down to the four sigma level. The statistical deconvolution procedure is described in detail. Over a temperature range from 155 to 200 °C, a total of more than 75 000 interconnects were tested. None of the samples have shown an indication of early, or alternate, failure mechanisms. The activation energy of the EM mechanism studied here, namely the Cu incubation time, was determined to be Q=1.08±0.05 eV. We surmise that interface diffusion of Cu along the Al(Cu) sidewalls and along the top and bottom refractory layers, coupled with grain boundary diffusion within the interconnects, constitutes the Cu incubation mechanism.

Investigations of a Complex, Realistic Task: Intentional, Unsystematic, and Exhaustive Experimenters

ERIC Educational Resources Information Center

McElhaney, Kevin W.; Linn, Marcia C.

2011-01-01

This study examines how students' experimentation with a virtual environment contributes to their understanding of a complex, realistic inquiry problem. We designed a week-long, technology-enhanced inquiry unit on car collisions. The unit uses new technologies to log students' experimentation choices. Physics students (n = 148) in six diverse high…

A sEMG model with experimentally based simulation parameters.

PubMed

Wheeler, Katherine A; Shimada, Hiroshima; Kumar, Dinesh K; Arjunan, Sridhar P

2010-01-01

A differential, time-invariant, surface electromyogram (sEMG) model has been implemented. While it is based on existing EMG models, the novelty of this implementation is that it assigns more accurate distributions of variables to create realistic motor unit (MU) characteristics. Variables such as muscle fibre conduction velocity, jitter (the change in the interpulse interval between subsequent action potential firings) and motor unit size have been considered to follow normal distributions about an experimentally obtained mean. In addition, motor unit firing frequencies have been considered to have non-linear and type based distributions that are in accordance with experimental results. Motor unit recruitment thresholds have been considered to be related to the MU type. The model has been used to simulate single channel differential sEMG signals from voluntary, isometric contractions of the biceps brachii muscle. The model has been experimentally verified by conducting experiments on three subjects. Comparison between simulated signals and experimental recordings shows that the Root Mean Square (RMS) increases linearly with force in both cases. The simulated signals also show similar values and rates of change of RMS to the experimental signals.

[Development and effects of an e-learning program in operating room nursing for nursing students].

PubMed

Park, Eun Hee; Hwang, Seon Young

2011-02-01

This study was conducted to develop an e-Learning program that assists nursing students' clinical practice in operating room nursing and to examine the learning effects. Based on content and need analysis, 9 learning modules were developed for nursing care in operating rooms and with operating equipment. To verify the effects of the program, a quasi-experimental pretest-posttest control group design was employed. The participants in this study were 74 third-year nursing students (34 in the experimental and 40 in the control group) from a junior college in G-city, Korea, who were engaged in a one week clinical practicum in an operating unit. Frequencies, χ(2)-test and t-test with the SPSS program 17.0 were used to analyze the data. Knowledge was significantly higher in the experimental group compared to the control group (p=.018). However, there was no significant difference between the two groups in self-directed learning. The experimental group had significantly higher motivation toward learning, which was examined posttest only (p=.027). These results indicate that the implementation of an e-Learning program needs to be continued as an effective educational tool, but more research on the best way to implement e-Learning in students' practicum is needed.

Meteorite Unit Models for Structural Properties

NASA Astrophysics Data System (ADS)

Agrawal, Parul; Carlozzi, Alexander A.; Karajeh, Zaid S.; Bryson, Kathryn L.

2017-10-01

To assess the threat posed by an asteroid entering Earth’s atmosphere, one must predict if, when, and how it fragments during entry. A comprehensive understanding of the asteroid material properties is needed to achieve this objective. At present, the meteorite material found on earth are the only objects from an entering asteroid that can be used as representative material and be tested inside a laboratory. Due to complex composition, it is challenging and expensive to obtain reliable material properties by means of laboratory test for a family of meteorites. In order to circumvent this challenge, meteorite unit models are developed to determine the effective material properties including Young’s modulus, compressive and tensile strengths and Poisson’s ratio, that in turn would help deduce the properties of asteroids. The meteorite unit model is a representative volume that accounts for diverse minerals, porosity, cracks and matrix composition.The Young’s Modulus and Poisson’s Ratio in the meteorite units are calculated by performing several hundreds of Monte Carlo simulations by randomly distributing the various phases inside these units. Once these values are obtained, cracks are introduced in these units. The size, orientation and distribution of cracks are derived by CT-scans and visual scans of various meteorites. Subsequently, simulations are performed to attain stress-strain relations, strength and effective modulus values in the presence of these cracks. The meteorite unit models are presented for H, L and LL ordinary chondrites, as well as for terrestrial basalt. In the case of the latter, data from the simulations is compared with experimental data to validate the methodology. These meteorite unit models will be subsequently used in fragmentation modeling of full scale asteroids.

Oxidizer heat exchanger component test

NASA Technical Reports Server (NTRS)

Kanic, P. G.

1988-01-01

The RL10-IIB engine, is capable of multimode thrust operation. The engine operates at two low-thrust levels: tank head idle (THI), approximately 1 to 2 percent of full thrust; and pumped idle, 10 percent of full thrust. Operation at THI provides vehicle propellant settling thrust and efficient thermal conditioning; PI operation provides vehicle tank prepressurization and maneuver thrust for low-g deployment. Stable combustion of the RL10-IIB engine during the low-thrust operating modes can be accomplished by using a heat exchanger to supply gaseous oxygen to the propellant injector. The oxidized heat exchanger (OHE) vaporizes the liquid oxygen using hydrogen as the energy source. This report summarizes the test activity and post-test data analysis for two possible heat exchangers, each of which employs a completely different design philosophy. One design makes use of a low-heat transfer (PHT) approach in combination with a volume to attenuate pressure and flow oscillations. The test data showed that the LHT unit satisfied the oxygen exit quality of 0.95 or greater in both the THI and PI modes while maintaining stability. The HHT unit fulfilled all PI requirements; data for THI satisfactory operation is implied from experimental data that straddle the exact THI operating point.

Variation in gaze-following between two Asian colobine monkeys.

PubMed

Chen, Tao; Gao, Jie; Tan, Jingzhi; Tao, Ruoting; Su, Yanjie

2017-10-01

Gaze-following is a basic cognitive ability found in numerous primate and nonprimate species. However, little is known about this ability and its variation in colobine monkeys. We compared gaze-following of two Asian colobines-François' langurs (Trachypithecus francoisi) and golden snub-nosed monkeys (Rhinopithecus roxellana). Although both species live in small polygynous family units, units of the latter form multilevel societies with up to hundreds of individuals. François' langurs (N = 15) were less sensitive to the gaze of a human experimenter than were golden snub-nosed monkeys (N = 12). We then tested the two species using two classic inhibitory control tasks-the cylinder test and the A-not-B test. We found no difference between species in inhibitory control, which called into question the nonsocial explanation for François' langur's weaker sensitivity to human gaze. These findings are consistent with the social intelligence hypothesis, which predicted that golden snub-nosed monkeys would outperform François' langurs in gaze-following because of the greater size and complexity of their social groups. Furthermore, our results underscore the need for more comparative studies of cognition in colobines, which should provide valuable opportunities to test hypotheses of cognitive evolution.

End-to-end test of the electron-proton spectrometer

NASA Technical Reports Server (NTRS)

Cash, B. L.

1972-01-01

A series of end-to-end tests were performed to demonstrate the proper functioning of the complete Electron-Proton Spectrometer (EPS). The purpose of the tests was to provide experimental verification of the design and to provide a complete functional performance check of the instrument from the excitation of the sensors to and including the data processor and equipment test set. Each of the channels of the EPS was exposed to a calibrated beam of energetic particles, and counts were accumulated for a predetermined period of time for each of several energies. The counts were related to the known flux of particles to give a monodirectional response function for each channel. The measured response function of the test unit was compared to the response function determined for the calibration sensors from the data taken from the calibration program.

Experimental Results Obtained with Air Liquide Cold Compression System: CERN LHC and SNS Projects

NASA Astrophysics Data System (ADS)

Delcayre, F.; Courty, J.-C.; Hamber, F.; Hilbert, B.; Monneret, E.; Toia, J.-L.

2006-04-01

Large scale collider facilities will make intensive use of superconducting magnets, operating below 2.0 K. This dictates high-capacity refrigeration systems operating below 2.0 K. These systems, making use of cryogenic centrifugal compressors in a series arrangement with room temperature screw compressors will be coupled to a refrigerator, providing a certain power at 4.5 K. A first Air Liquide Cold Compression System (CCS) unit was built and delivered to CERN in 2001. Installed at the beginning of 2002, it was commissioned and tested successfully during year 2002. A series of four sets of identical CCS were then tested in 2004. Another set of four cryogenic centrifugal compressors (CCC) has been delivered to Thomas Jefferson National Accelerator Facility (JLAB) for the Spallation Neutron Source (SNS) in 2002. These compressors were tested and commissioned from December 2004 to July 2005. The experimental results obtained with these systems will be presented and discussed: the characteristics of the CCC will be detailed. The principles of control for the CCC in series will be detailed.

Arcjet nozzle area ratio effects

NASA Technical Reports Server (NTRS)

Curran, Francis M.; Sarmiento, Charles J.; Birkner, Bjorn W.; Kwasny, James

1990-01-01

An experimental investigation was conducted to determine the effect of nozzle area ratio on the operating characteristics and performance of a low power dc arcjet thruster. Conical thoriated tungsten nozzle inserts were tested in a modular laboratory arcjet thruster run on hydrogen/nitrogen mixtures simulating the decomposition products of hydrazine. The converging and diverging sides of the inserts had half angles of 30 and 20 degrees, respectively, similar to a flight type unit currently under development. The length of the diverging side was varied to change the area ratio. The nozzle inserts were run over a wide range of specific power. Current, voltage, mass flow rate, and thrust were monitored to provide accurate comparisons between tests. While small differences in performance were observed between the two nozzle inserts, it was determined that for each nozzle insert, arcjet performance improved with increasing nozzle area ratio to the highest area ratio tested and that the losses become very pronounced for area ratios below 50. These trends are somewhat different than those obtained in previous experimental and analytical studies of low Re number nozzles. It appears that arcjet performance can be enhanced via area ratio optimization.

Arcjet Nozzle Area Ratio Effects

NASA Technical Reports Server (NTRS)

Curran, Francis M.; Sarmiento, Charles J.; Birkner, Bjorn W.; Kwasny, James

1990-01-01

An experimental investigation was conducted to determine the effect of nozzle area ratio on the operating characteristics and performance of a low power dc arcjet thruster. Conical thoriated tungsten nozzle inserts were tested in a modular laboratory arcjet thruster run on hydrogen/nitrogen mixtures simulating the decomposition products of hydrazine. The converging and diverging sides of the inserts had half angles of 30 and 20 degrees, respectively, similar to a flight type unit currently under development. The length of the diverging side was varied to change the area ratio. The nozzle inserts were run over a wide range of specific power. Current, voltage, mass flow rate, and thrust were monitored to provide accurate comparisons between tests. While small differences in performance were observed between the two nozzle inserts, it was determined that for each nozzle insert, arcjet performance improved with increasing nozzle area ratio to the highest area ratio tested and that the losses become very pronounced for area ratios below 50. These trends are somewhat different than those obtained in previous experimental and analytical studies of low Re number nozzles. It appears that arcjet performance can be enhanced via area ratio optimization.

A Review of the Experimental and Modeling Development of a Water Phase Change Heat Exchanger for Future Exploration Support Vehicles

NASA Technical Reports Server (NTRS)

Cognata, Thomas; Leimkuehler, Thomas; Ramaswamy, Balasubramaniam; Nayagam, Vedha; Hasan, Mohammad; Stephan, Ryan

2011-01-01

Water affords manifold benefits for human space exploration. Its properties make it useful for the storage of thermal energy as a Phase Change Material (PCM) in thermal control systems, in radiation shielding against Solar Particle Events (SPE) for the protection of crew members, and it is indisputably necessary for human life support. This paper envisions a single application for water which addresses these benefits for future exploration support vehicles and it describes recent experimental and modeling work that has been performed in order to arrive at a description of the thermal behavior of such a system. Experimental units have been developed and tested which permit the evaluation of the many parameters of design for such a system with emphasis on the latent energy content, temperature rise, mass, and interstitial material geometry. The experimental results are used to develop a robust and well correlated model which is intended to guide future design efforts toward the multi-purposed water PCM heat exchanger envisioned.

Metrological analysis of the human foot: 3D multisensor exploration

NASA Astrophysics Data System (ADS)

Muñoz Potosi, A.; Meneses Fonseca, J.; León Téllez, J.

2011-08-01

In the podiatry field, many of the foot dysfunctions are mainly generated due to: Congenital malformations, accidents or misuse of footwear. For the treatment or prevention of foot disorders, the podiatrist diagnoses prosthesis or specific adapted footwear, according to the real dimension of foot. Therefore, it is necessary to acquire 3D information of foot with 360 degrees of observation. As alternative solution, it was developed and implemented an optical system of threedimensional reconstruction based in the principle of laser triangulation. The system is constituted by an illumination unit that project a laser plane into the foot surface, an acquisition unit with 4 CCD cameras placed around of axial foot axis, an axial moving unit that displaces the illumination and acquisition units in the axial axis direction and a processing and exploration unit. The exploration software allows the extraction of distances on three-dimensional image, taking into account the topography of foot. The optical system was tested and their metrological performances were evaluated in experimental conditions. The optical system was developed to acquire 3D information in order to design and make more appropriate footwear.

The Stephen F. Austin Experimental Forest

Treesearch

Cary C. Russell; Ronald E. Thill; David L. Kulhavy

2002-01-01

On December 14, 1944, the Seventy-Eighth United States Congress passed a bill that authorized the transfer of 2,560 acres in Nacogdoches County, Texas, to the research branch of the United States Forest Service (USFS). This land became the Stephen F. Austin Experimental Forest (SFAEF) on September 19. 1945. One of eighty-one federal experimental forests and ranges...

Development of a 12-Thrust Chamber Kerosene /Oxygen Primary Rocket Sub-System for an Early (1964) Air-Augmented Rocket Ground-Test System

NASA Technical Reports Server (NTRS)

Pryor, D.; Hyde, E. H.; Escher, W. J. D.

1999-01-01

Airbreathing/Rocket combined-cycle, and specifically rocket-based combined- cycle (RBCC), propulsion systems, typically employ an internal engine flow-path installed primary rocket subsystem. To achieve acceptably short mixing lengths in effecting the "air augmentation" process, a large rocket-exhaust/air interfacial mixing surface is needed. This leads, in some engine design concepts, to a "cluster" of small rocket units, suitably arrayed in the flowpath. To support an early (1964) subscale ground-test of a specific RBCC concept, such a 12-rocket cluster was developed by NASA's Marshall Space Flight Center (MSFC). The small primary rockets used in the cluster assembly were modified versions of an existing small kerosene/oxygen water-cooled rocket engine unit routinely tested at MSFC. Following individual thrust-chamber tests and overall subsystem qualification testing, the cluster assembly was installed at the U. S. Air Force's Arnold Engineering Development Center (AEDC) for RBCC systems testing. (The results of the special air-augmented rocket testing are not covered here.) While this project was eventually successfully completed, a number of hardware integration problems were met, leading to catastrophic thrust chamber failures. The principal "lessons learned" in conducting this early primary rocket subsystem experimental effort are documented here as a basic knowledge-base contribution for the benefit of today's RBCC research and development community.

Aeroheating Testing and Predictions for Project Orion CEV at Turbulent Conditions

NASA Technical Reports Server (NTRS)

Hollis, Brian R.; Berger, Karen T.; Horvath, Thomas J.; Coblish, Joseph J.; Norris, Joseph D.; Lillard, Randolph P.; Kirk, Benjamin S.

2009-01-01

An investigation of the aeroheating environment of the Project Orion Crew Exploration Vehicle was performed in the Arnold Engineering Development Center Hypervelocity Wind Tunnel No. 9 Mach 8 and Mach 10 nozzles and in the NASA Langley Research Center 20 - Inch Mach 6 Air Tunnel. Heating data were obtained using a thermocouple-instrumented approx.0.035-scale model (0.1778-m/7-inch diameter) of the flight vehicle. Runs were performed in the Tunnel 9 Mach 10 nozzle at free stream unit Reynolds numbers of 1x10(exp 6)/ft to 20x10(exp 6)/ft, in the Tunnel 9 Mach 8 nozzle at free stream unit Reynolds numbers of 8 x 10(exp 6)/ft to 48x10(exp 6)/ft, and in the 20-Inch Mach 6 Air Tunnel at free stream unit Reynolds numbers of 1x10(exp 6)/ft to 7x10(exp 6)/ft. In both facilities, enthalpy levels were low and the test gas (N2 in Tunnel 9 and air in the 20-Inch Mach 6) behaved as a perfect-gas. These test conditions produced laminar, transitional and turbulent data in the Tunnel 9 Mach 10 nozzle, transitional and turbulent data in the Tunnel 9 Mach 8 nozzle, and laminar and transitional data in the 20- Inch Mach 6 Air Tunnel. Laminar and turbulent predictions were generated for all wind tunnel test conditions and comparisons were performed with the experimental data to help define the accuracy of computational method. In general, it was found that both laminar data and predictions, and turbulent data and predictions, agreed to within less than the estimated 12% experimental uncertainty estimate. Laminar heating distributions from all three data sets were shown to correlate well and demonstrated Reynolds numbers independence when expressed in terms of the Stanton number based on adiabatic wall-recovery enthalpy. Transition onset locations on the leeside centerline were determined from the data and correlated in terms of boundary-layer parameters. Finally turbulent heating augmentation ratios were determined for several body-point locations and correlated in terms of the boundary-layer momentum Reynolds number.

Evaluation of a Unique Defibrillation Unit with Dual-Vector Biphasic Waveform Capabilities: Towards a Miniaturized Defibrillator.

PubMed

Okamura, Hideo; Desimone, Christopher V; Killu, Ammar M; Gilles, Emily J; Tri, Jason; Asirvatham, Roshini; Ladewig, Dejae J; Suddendorf, Scott H; Powers, Joanne M; Wood-Wentz, Christina M; Gray, Peter D; Raymond, Douglas M; Savage, Shelley J; Savage, Walter T; Bruce, Charles J; Asirvatham, Samuel J; Friedman, Paul A

2017-02-01

Automated external defibrillators can provide life-saving therapies to treat ventricular fibrillation. We developed a prototype unit that can deliver a unique shock waveform produced by four independent capacitors that is delivered through two shock vectors, with the rationale of providing more robust shock pathways during emergent defibrillation. We describe the initial testing and feasibility of this unique defibrillation unit, features of which may enable downsizing of current defibrillator devices. We tested our defibrillation unit in four large animal models (two canine and two swine) under general anesthesia. Experimental defibrillation thresholds (DFT) were obtained by delivery of a unique waveform shock pulse via a dual-vector pathway with four defibrillation pads (placed across the chest). DFTs were measured and compared with those of a commercially available biphasic defibrillator (Zoll M series, Zoll Medical, Chelmsford, MA, USA) tested in two different vectors. Shocks were delivered after 10 seconds of stable ventricular fibrillation and the output characteristics and shock outcome recorded. Each defibrillation series used a step-down to failure protocol to define the defibrillation threshold. A total of 96 shocks were delivered during ventricular fibrillation in four large animals. In comparison to the Zoll M series, which delivered a single-vector, biphasic shock, the energy required for successful defibrillation using the unique dual-vector biphasic waveform did not differ significantly (P = 0.65). Our early findings support the feasibility of a unique external defibrillation unit using a dual-vector biphasic waveform approach. This warrants further study to leverage this unique concept and work toward a miniaturized, portable shock delivery system. © 2016 Wiley Periodicals, Inc.

Bayesian Dose-Response Modeling in Sparse Data

NASA Astrophysics Data System (ADS)

Kim, Steven B.

This book discusses Bayesian dose-response modeling in small samples applied to two different settings. The first setting is early phase clinical trials, and the second setting is toxicology studies in cancer risk assessment. In early phase clinical trials, experimental units are humans who are actual patients. Prior to a clinical trial, opinions from multiple subject area experts are generally more informative than the opinion of a single expert, but we may face a dilemma when they have disagreeing prior opinions. In this regard, we consider compromising the disagreement and compare two different approaches for making a decision. In addition to combining multiple opinions, we also address balancing two levels of ethics in early phase clinical trials. The first level is individual-level ethics which reflects the perspective of trial participants. The second level is population-level ethics which reflects the perspective of future patients. We extensively compare two existing statistical methods which focus on each perspective and propose a new method which balances the two conflicting perspectives. In toxicology studies, experimental units are living animals. Here we focus on a potential non-monotonic dose-response relationship which is known as hormesis. Briefly, hormesis is a phenomenon which can be characterized by a beneficial effect at low doses and a harmful effect at high doses. In cancer risk assessments, the estimation of a parameter, which is known as a benchmark dose, can be highly sensitive to a class of assumptions, monotonicity or hormesis. In this regard, we propose a robust approach which considers both monotonicity and hormesis as a possibility. In addition, We discuss statistical hypothesis testing for hormesis and consider various experimental designs for detecting hormesis based on Bayesian decision theory. Past experiments have not been optimally designed for testing for hormesis, and some Bayesian optimal designs may not be optimal under a wrong parametric assumption. In this regard, we consider a robust experimental design which does not require any parametric assumption.

Evaluating Middle School Students' Spatial-scientific Performance in Earth-space Science

NASA Astrophysics Data System (ADS)

Wilhelm, Jennifer; Jackson, C.; Toland, M. D.; Cole, M.; Wilhelm, R. J.

2013-06-01

Many astronomical concepts cannot be understood without a developed understanding of four spatial-mathematics domains defined as follows: a) Geometric Spatial Visualization (GSV) - Visualizing the geometric features of a system as it appears above, below, and within the system’s plane; b) Spatial Projection (SP) - Projecting to a different location and visualizing from that global perspective; c) Cardinal Directions (CD) - Distinguishing directions (N, S, E, W) in order to document an object’s vector position in space; and d) Periodic Patterns - (PP) Recognizing occurrences at regular intervals of time and/or space. For this study, differences were examined between groups of sixth grade students’ spatial-scientific development pre/post implementation of an Earth/Space unit. Treatment teachers employed a NASA-based curriculum (Realistic Explorations in Astronomical Learning), while control teachers implemented their regular Earth/Space units. A 2-level hierarchical linear model was used to evaluate student performance on the Lunar Phases Concept Inventory (LPCI) and four spatial-mathematics domains, while controlling for two variables (gender and ethnicity) at the student level and one variable (teaching experience) at the teacher level. Overall LPCI results show pre-test scores predicted post-test scores, boys performed better than girls, and Whites performed better than non-Whites. We also compared experimental and control groups’ by spatial-mathematics domain outcomes. For GSV, it was found that boys, in general, tended to have higher GSV post-scores. For domains CD and SP, no statistically significant differences were observed. PP results show Whites performed better than non-Whites. Also for PP, a significant cross-level interaction term (gender-treatment) was observed, which means differences in control and experimental groups are dependent on students’ gender. These findings can be interpreted as: (a) the experimental girls scored higher than the control girls and/or (b) the control group displayed a gender gap in favor of boys while no gender gap was displayed within the experimental group.

A computer-based education intervention to enhance surrogates' informed consent for genomics research.

PubMed

Shelton, Ann K; Freeman, Bradley D; Fish, Anne F; Bachman, Jean A; Richardson, Lloyd I

2015-03-01

Many research studies conducted today in critical care have a genomics component. Patients' surrogates asked to authorize participation in genomics research for a loved one in the intensive care unit may not be prepared to make informed decisions about a patient's participation in the research. To examine the effectiveness of a new, computer-based education module on surrogates' understanding of the process of informed consent for genomics research. A pilot study was conducted with visitors in the waiting rooms of 2 intensive care units in a Midwestern tertiary care medical center. Visitors were randomly assigned to the experimental (education module plus a sample genomics consent form; n = 65) or the control (sample genomics consent form only; n = 69) group. Participants later completed a test on informed genomics consent. Understanding the process of informed consent was greater (P = .001) in the experimental group than in the control group. Specifically, compared with the control group, the experimental group had a greater understanding of 8 of 13 elements of informed consent: intended benefits of research (P = .02), definition of surrogate consenter (P= .001), withdrawal from the study (P = .001), explanation of risk (P = .002), purpose of the institutional review board (P = .001), definition of substituted judgment (P = .03), compensation for harm (P = .001), and alternative treatments (P = .004). Computer-based education modules may be an important addition to conventional approaches for obtaining informed consent in the intensive care unit. Preparing patients' family members who may consider serving as surrogate consenters is critical to facilitating genomics research in critical care. ©2015 American Association of Critical-Care Nurses.

The effect of massage therapy on occupational stress of Intensive Care Unit nurses.

PubMed

Nazari, Fateme; Mirzamohamadi, Mojtaba; Yousefi, Hojatollah

2015-01-01

One of the main causes of stress in the lives of people is their jobs. Occupational stress is causing a wide range of significant issues in health and community services. Nursing is the most stressful profession in the health services. Massage therapy is one way of coping with stress. This study was conducted to determine the effect of massage therapy on stress in nurses. This study was a clinical trial on 66 male and female nurses working in intensive care units (dialysis, ICU, and CCU) of Isfahan University of Medical Sciences, Iran, in 2013. Participants were selected according to the aims and inclusion criteria of the study. Then, they were randomly divided into experimental and control groups. The Occupational Stress Inventory (OSI) (Osipow and Spokane, 1987) was completed by participants of the two groups before, immediately after, and 2 weeks after the intervention. General Swedish massage was performed on participants of the experimental group for 25 min in each session, twice a week for 4 weeks. Data were analyzed by descriptive and inferential statistics [Chi-square, t-test, and repeated measures analysis of variance (ANOVA)] using SPSS software. Results showed that the difference in overall mean occupation stress scores between experimental and control groups 2 weeks after the intervention was significant (P < 0.001). According to the results, it is recommended that massage, as a valuable noninvasive method, be used for nurses in intensive care units to reduce their stress, promote mental health, and prevent the decrease in quality of nursing work life.

Characterizing Adhesion between a Micropatterned Surface and a Soft Synthetic Tissue.

PubMed

Kern, Madalyn D; Qi, Yuan; Long, Rong; Rentschler, Mark E

2017-01-31

The work of adhesion and work of separation are characteristic properties of a contact interface that describe the amount of energy per unit area required to adhere or separate two contacting substrates, respectively. In this work, the authors present experimental and data analysis procedures that allow the contact interface between a soft synthetic tissue and a smooth or micropatterned poly(dimethylsiloxane) (PDMS) substrate to be characterized in terms of these characteristic parameters. Because of physical geometry limitations, the experimental contact geometry chosen for this study differs from conventional test geometries. Therefore, the authors used finite element modeling to develop correction factors specific to the experimental contact geometry used in this work. A work of adhesion was directly extracted from experimental data while the work of separation was estimated on the basis of experimental results. These values are compared to other theoretical calculations for validation. The results of this work indicate that the micropatterned PDMS substrate significantly decreases both the work of adhesion and work of separation as compared to a smooth PDMS substrate when in contact with a soft synthetic tissue substrate.

Unmanned powered balloons

NASA Technical Reports Server (NTRS)

Korn, A. O.

1975-01-01

In the late 1960's several governmental agencies sponsored efforts to develop unmanned, powered balloon systems for scientific experimentation and military operations. Some of the programs resulted in hardware and limited flight tests; others, to date, have not progressed beyond the paper study stage. Balloon system designs, materials, propulsion units and capabilities are briefly described, and critical problem areas are pointed out which require further study in order to achieve operational powered balloon systems capable of long duration flight at high altitudes.

Interaction between polymer constituents and the structure of biopolymers

NASA Technical Reports Server (NTRS)

Rein, R.

1974-01-01

The paper reviews the current status of methods for calculating intermolecular interactions between biopolymer units. The nature of forces contributing to the various domains of intermolecular separations is investigated, and various approximations applicable in the respective regions are examined. The predictive value of current theory is tested by establishing a connection with macroscopic properties and comparing the theoretical predicted values with those derived from experimental data. This has led to the introduction of a statistical model describing DNA.

The Effects of the Activities of Current Textbook and 5 E Model on the Attitude of the Students: Sample of "The Global Effects of Natural Resources Unit"

ERIC Educational Resources Information Center

Uzunoz, Abdulkadir

2011-01-01

This study aimed to determine the effects of the activities of current textbook and 5 E Model on the attitude of the students. This study is a research as an experimental model. For testing the effects of geography education supported by 5 E model and geography education based on activities of current textbook attitude of students, controlled…

Virulence of Curvularia in a murine model.

PubMed

Paredes, Katihuska; Capilla, Javier; Sutton, Deanna A; Mayayo, Emilio; Fothergill, Annette W; Guarro, Josep

2013-09-01

We have evaluated the virulence of two clinically relevant species of Curvularia; Curvularia spicifera and C. hawaiiensis, using an experimental model of disseminated infection in immunocompromised mice. Several inocula were tested over a range 1 × 10(3) -1 × 10(6) colony-forming units/animal. Both species had a similar behaviour, producing a high mortality. Tissue burden and histopathology studies demonstrated that lung was the organ most affected. © 2013 Blackwell Verlag GmbH.

Effects of two grading techniques of zirconia material on the fatigue limit of full-contour 3-unit fixed dental prostheses

PubMed Central

Villefort, Regina Furbino; Amaral, Marina; Pereira, Gabriel Kalil Rocha; Campos, Tiago Moreira Bastos; Zhang, Yu; Bottino, Marco Antonio; Valandro, Luiz Felipe; de Melo, Renata Marques

2017-01-01

Objective This study evaluated the effects of two grading zirconia techniques on the fatigue limit of 3-unit fixed dental prostheses (FDPs). Methods Presintered blocks of 3Y-TZP were milled to obtain sixty-nine 3-unit FDPs, which were divided into three groups (n = 23). The control group (CTL) was sintered and glazed following manufacturer’s instructuctions. The two experimental groups presintered FDPs received a surface silica/glass infiltration treatment before the sintering process. Silica sol-gel group (SSG) was graded by the sol-gel processing route, while the glass-zirconia-glass group (GZG) was graded by an enameling technique. Graded groups did not receive a glaze layer after sintering. All FDPs were then luted with a dual-curing resin cement on composite abutments, embedded in polyurethane and stored in water for five days. The initial load of the fatigue test was calculated based on the results of the monotonic testing applied on three specimens of each group. To determine the fatigue limit, 20 samples of each group were subjected to staircase testing (100,000 cycles/5 Hz). Results The fatigue limits (in Newtons) were CTL = 1607.27, SSG = 1824.31, and GZG = 2006.57, and the Dixon and Mood test indicated statistically significant differences among groups (95% confidence interval). Significance The infiltration of silica and glass on bulk zirconia, by two different grading methods, increased the fatigue limits of monolithic zirconia FDPs. PMID:28118929

Gas-fired duplex free-piston Stirling refrigerator

NASA Astrophysics Data System (ADS)

Urieli, L.

1984-03-01

The duplex free-piston Stirling refrigerator is a potentially high efficiency, high reliability device which is ideally suited to the home appliance field, in particular as a gas-fired refrigerator. It has significant advantages over other equivalent devices including freedom from halogenated hydrocarbons, extremely low temperatures available at a high efficiency, integrated water heating, and simple burner system control. The design and development of a portable working demonstration gas-fired duplex Stirling refrigeration unit is described. A unique combination of computer aided development and experimental development was used, enabling a continued interaction between the theoretical analysis and practical testing and evaluation. A universal test rig was developed in order to separately test and evaluate major subunits, enabling a smooth system integration phase.

Three-Dimensional Simulation of Base Bleed Unit with AP/HTPB Propellant in Fast Cook-off Conditions

NASA Astrophysics Data System (ADS)

Li, Wen-feng; Yu, Yong-gang; Ye, Rui; Yang, Hou-wen

2017-07-01

In this work, a three-dimensional unsteady heat transfer model of base bleed unit with trilobite ammonium perchlorate (AP)/hydroxyl-terminated polybutadiene (HTPB) composite solid propellant is presented to analyze the cook-off characteristics. According to the two-step chemical reaction of AP/HTPB propellant, a small-scale cook-off test is established. A comparison of the experimental and calculated results is made to verify the rationality of the computation model. On this basis, a cook-off numerical simulation of the base bleed unit at the heating rates of 0.33, 0.58 and 0.83 K/s is presented to investigate the ignition and initiation characteristics. The results show that the ignitions occur on the head face of the AP/HTPB propellant and near the internal gas chamber in these conditions. As the heating rate increases, the runaway time decreases and the ignition temperature rises.

Determining the effectiveness of illustrated communication material for communication with intubated patients at an intensive care unit.

PubMed

Otuzoğlu, Münevver; Karahan, Azize

2014-10-01

Communication with non-speaking patients in intensive care unit is stress for both nurse and patients. Semi-experimental study that took place at a University Hospital was to develop illustrated material for patient communication and determine its effectiveness. The study sample consisted of 90 intubated patients at the Adult Cardiovascular Intensive Care Unit who had undergone open heart surgery. The patients were divided into the intervention and control groups. Data analysis was with descriptive statistics and the χ(2) test. The illustrated communication material was stated to be helpful by 77.8% and partially helpful by 22.2% of the intervention group patients regarding the communication between the health-care staff and the patients. Control group patients had more difficulties communicating with the health-care staff. Illustrated communication material was an effective method in communicating with intubated patients. © 2013 Wiley Publishing Asia Pty Ltd.

Effect of stress management interventions on job stress among nurses working in critical care units.

PubMed

Light Irin, C; Bincy, R

2012-01-01

Stress in nurses affects their health and increases absenteeism, attrition rate, injury claims, infection rates and errors in treating patients. This in turn significantly increases the cost of employment in healthcare units. Proper management of stress ensures greater efficiency at work place and improved wellbeing of the employee. Therefore, a pre-experimental study was conducted among 30 Critical Care Unit nurses working inMedical College Hospital, Thiruvananthapuram, (Kerala) to assess the effect of stress management interventions such as Job Stress Awareness, Assertiveness Training, Time Management, andProgressive Muscle Relaxation on job stress. The results showed that caring for patients, general job requirements and workload were the major sources of stress for the nurses. The level of severe stress was reduced from 60 percent to 20 percent during post-test. The Stress Management Interventions were statistically effective in reducing the stress of nurses at p<0.001 level.

Methane enrichment digestion experiments at the anaerobic experimental test unit at Walt Disney World. Final report, March 1989-August 1990

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

Srivastava, V.J.; Hill, A.H.

1993-06-01

The goal of the project was to determine the technical feasibility of utilizing a novel concept in anaerobic digestion, in-situ methane enrichment digestion or MED for producing utility-grade gas from a pilot-scale anaerobic digester. MED tests conducted during this program consistently achieved digester product gas with a methane (CH4) content of greater than 90% (on a dry-, nitrogen-free basis). The MED concept, because it requires relatively simple equipment and modest energy input, has the potential to simplify gas cleanup requirements and substantially reduce the cost of converting wastes and biomass to pipeline quality gas.

An assessment of RELAP5-3D using the Edwards-O'Brien Blowdown problem

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

Tomlinson, E.T.; Aumiller, D.L.

1999-07-01

The RELAP5-3D (version bt) computer code was used to assess the United States Nuclear Regulatory Commission's Standard Problem 1 (Edwards-O'Brien Blowdown Test). The RELAP5-3D standard installation problem based on the Edwards-O'Brien Blowdown Test was modified to model the appropriate initial conditions and to represent the proper location of the instruments present in the experiment. The results obtained using the modified model are significantly different from the original calculation indicating the need to model accurately the experimental conditions if an accurate assessment of the calculational model is to be obtained.

Nutrient balancing for phytoremediation enhancement of urea manufacturing raw wastewater.

PubMed

Yavari, Sara; Malakahmad, Amirhossein; Sapari, Nasiman B; Yavari, Saba; Khan, Eakalak

2017-11-01

Application of urea manufacturing wastewater to teak (Tectona grandis) trees, a fast growing tropical timber plants, is an environmentally-friendly and cost-effective alternative for treatment of nitrogen-rich wastewater. However, the plant growth is strongly limited by lack of phosphorus (P) and potassium (K) elements when the plants are irrigated with wastewater containing high concentration of nitrogen (N). A greenhouse experiment was conducted to optimize the efficiency of teak-based remediation systems in terms of nutrient balance. Twelve test solutions consisted of 4 levels of P (95, 190, 570, 1140 mgL -1 ) and 3 levels of K (95, 190, 570 mgL -1 ) with a constant level of N (190 mgL -1 ) were applied to teak seedlings every four days during the study period. Evapotranspiration rate, nutrient removal percentage, leaf surface area, dry weight and nutrient contents of experimental plants were determined and compared with those grown in control solution containing only N (N:P:K = 1:0:0). Teak seedlings grown in units with 1:0.5:1 N:P:K ratio were highly effective at nutrient removal upto 47%, 48% and 49% for N, P and K, respectively. Removal efficiency of teak plants grown in other experimental units decreased with increasing P and K concentrations in test solutions. The lowest nutrient removal and plant growth were recorded in units with 1:6:0.5 N:P:K ratio which received the highest ratio of P to K. The findings indicated that teak seedlings functioned effectively as phytoremediation plants for N-rich wastewater treatment when they were being supplied with proper concentrations of P and K. Copyright © 2017. Published by Elsevier Ltd.

Multi-Evaporator Miniature Loop Heat Pipe for Small Spacecraft Thermal Control. Part 2; Validation Results

NASA Technical Reports Server (NTRS)

Ku, Jentung; Ottenstein, Laura; Douglas, Donya; Hoang, Triem

2010-01-01

Under NASA s New Millennium Program Space Technology 8 (ST 8) Project, Goddard Space Fight Center has conducted a Thermal Loop experiment to advance the maturity of the Thermal Loop technology from proof of concept to prototype demonstration in a relevant environment , i.e. from a technology readiness level (TRL) of 3 to a level of 6. The thermal Loop is an advanced thermal control system consisting of a miniature loop heat pipe (MLHP) with multiple evaporators and multiple condensers designed for future small system applications requiring low mass, low power, and compactness. The MLHP retains all features of state-of-the-art loop heat pipes (LHPs) and offers additional advantages to enhance the functionality, performance, versatility, and reliability of the system. An MLHP breadboard was built and tested in the laboratory and thermal vacuum environments for the TRL 4 and TRL 5 validations, respectively, and an MLHP proto-flight unit was built and tested in a thermal vacuum chamber for the TRL 6 validation. In addition, an analytical model was developed to simulate the steady state and transient behaviors of the MLHP during various validation tests. The MLHP demonstrated excellent performance during experimental tests and the analytical model predictions agreed very well with experimental data. All success criteria at various TRLs were met. Hence, the Thermal Loop technology has reached a TRL of 6. This paper presents the validation results, both experimental and analytical, of such a technology development effort.

The Wilcoxon signed rank test for paired comparisons of clustered data.

PubMed

Rosner, Bernard; Glynn, Robert J; Lee, Mei-Ling T

2006-03-01

The Wilcoxon signed rank test is a frequently used nonparametric test for paired data (e.g., consisting of pre- and posttreatment measurements) based on independent units of analysis. This test cannot be used for paired comparisons arising from clustered data (e.g., if paired comparisons are available for each of two eyes of an individual). To incorporate clustering, a generalization of the randomization test formulation for the signed rank test is proposed, where the unit of randomization is at the cluster level (e.g., person), while the individual paired units of analysis are at the subunit within cluster level (e.g., eye within person). An adjusted variance estimate of the signed rank test statistic is then derived, which can be used for either balanced (same number of subunits per cluster) or unbalanced (different number of subunits per cluster) data, with an exchangeable correlation structure, with or without tied values. The resulting test statistic is shown to be asymptotically normal as the number of clusters becomes large, if the cluster size is bounded. Simulation studies are performed based on simulating correlated ranked data from a signed log-normal distribution. These studies indicate appropriate type I error for data sets with > or =20 clusters and a superior power profile compared with either the ordinary signed rank test based on the average cluster difference score or the multivariate signed rank test of Puri and Sen. Finally, the methods are illustrated with two data sets, (i) an ophthalmologic data set involving a comparison of electroretinogram (ERG) data in retinitis pigmentosa (RP) patients before and after undergoing an experimental surgical procedure, and (ii) a nutritional data set based on a randomized prospective study of nutritional supplements in RP patients where vitamin E intake outside of study capsules is compared before and after randomization to monitor compliance with nutritional protocols.

A Comparison of Classical Force-Fields for Molecular Dynamics Simulations of Lubricants

PubMed Central

Ewen, James P.; Gattinoni, Chiara; Thakkar, Foram M.; Morgan, Neal; Spikes, Hugh A.; Dini, Daniele

2016-01-01

For the successful development and application of lubricants, a full understanding of their complex nanoscale behavior under a wide range of external conditions is required, but this is difficult to obtain experimentally. Nonequilibrium molecular dynamics (NEMD) simulations can be used to yield unique insights into the atomic-scale structure and friction of lubricants and additives; however, the accuracy of the results depend on the chosen force-field. In this study, we demonstrate that the use of an accurate, all-atom force-field is critical in order to; (i) accurately predict important properties of long-chain, linear molecules; and (ii) reproduce experimental friction behavior of multi-component tribological systems. In particular, we focus on n-hexadecane, an important model lubricant with a wide range of industrial applications. Moreover, simulating conditions common in tribological systems, i.e., high temperatures and pressures (HTHP), allows the limits of the selected force-fields to be tested. In the first section, a large number of united-atom and all-atom force-fields are benchmarked in terms of their density and viscosity prediction accuracy of n-hexadecane using equilibrium molecular dynamics (EMD) simulations at ambient and HTHP conditions. Whilst united-atom force-fields accurately reproduce experimental density, the viscosity is significantly under-predicted compared to all-atom force-fields and experiments. Moreover, some all-atom force-fields yield elevated melting points, leading to significant overestimation of both the density and viscosity. In the second section, the most accurate united-atom and all-atom force-field are compared in confined NEMD simulations which probe the structure and friction of stearic acid adsorbed on iron oxide and separated by a thin layer of n-hexadecane. The united-atom force-field provides an accurate representation of the structure of the confined stearic acid film; however, friction coefficients are consistently under-predicted and the friction-coverage and friction-velocity behavior deviates from that observed using all-atom force-fields and experimentally. This has important implications regarding force-field selection for NEMD simulations of systems containing long-chain, linear molecules; specifically, it is recommended that accurate all-atom potentials, such as L-OPLS-AA, are employed. PMID:28773773

A Comparison of Classical Force-Fields for Molecular Dynamics Simulations of Lubricants.

PubMed

Ewen, James P; Gattinoni, Chiara; Thakkar, Foram M; Morgan, Neal; Spikes, Hugh A; Dini, Daniele

2016-08-02

For the successful development and application of lubricants, a full understanding of their complex nanoscale behavior under a wide range of external conditions is required, but this is difficult to obtain experimentally. Nonequilibrium molecular dynamics (NEMD) simulations can be used to yield unique insights into the atomic-scale structure and friction of lubricants and additives; however, the accuracy of the results depend on the chosen force-field. In this study, we demonstrate that the use of an accurate, all-atom force-field is critical in order to; (i) accurately predict important properties of long-chain, linear molecules; and (ii) reproduce experimental friction behavior of multi-component tribological systems. In particular, we focus on n -hexadecane, an important model lubricant with a wide range of industrial applications. Moreover, simulating conditions common in tribological systems, i.e., high temperatures and pressures (HTHP), allows the limits of the selected force-fields to be tested. In the first section, a large number of united-atom and all-atom force-fields are benchmarked in terms of their density and viscosity prediction accuracy of n -hexadecane using equilibrium molecular dynamics (EMD) simulations at ambient and HTHP conditions. Whilst united-atom force-fields accurately reproduce experimental density, the viscosity is significantly under-predicted compared to all-atom force-fields and experiments. Moreover, some all-atom force-fields yield elevated melting points, leading to significant overestimation of both the density and viscosity. In the second section, the most accurate united-atom and all-atom force-field are compared in confined NEMD simulations which probe the structure and friction of stearic acid adsorbed on iron oxide and separated by a thin layer of n -hexadecane. The united-atom force-field provides an accurate representation of the structure of the confined stearic acid film; however, friction coefficients are consistently under-predicted and the friction-coverage and friction-velocity behavior deviates from that observed using all-atom force-fields and experimentally. This has important implications regarding force-field selection for NEMD simulations of systems containing long-chain, linear molecules; specifically, it is recommended that accurate all-atom potentials, such as L-OPLS-AA, are employed.

Evaluation of Antimicrobial and Healing Activities of Frog Skin on Guinea Pigs Wounds

PubMed Central

Rezazade Bazaz, Mahere; Mashreghi, Mohammad; Mahdavi Shahri, Nasser; Mashreghi, Mansour; Asoodeh, Ahmad; Behnam Rassouli, Morteza

2015-01-01

Background: Frog skin secretions have potentials against a wide spectrum of bacteria. Also, frog skin compositions have healing properties. Objectives: The aim of this study was to investigate the antibacterial potentials along with healing properties of frog skin Rana ridibunda, a species which thoroughly lives in Iran marshes, as a biological dressing on wounds. Materials and Methods: In this study, excisional wounds, dressed with frog skin, were compared between experimental and control groups of guinea pigs. In the experimental groups, wounds were dressed with the dermal (FS) and epidermal (RFS) sides of fresh frog R. ridibunda skin, while only usual cotton gauze covered the wounds of the control group. Furthermore, microbial samples were taken on different days (0, 3, 5, and 7 days post injury) to count the number of the colony-forming units. Additionally, the microbial penetration test was performed on frog skin and then the progression of wound closure was evaluated. Results: In the microbial studies, the bacterial load considerably declined in the wounds treated with FS and RFS compared with the control wounds. On day 7 post injury, the numbers of the colony-forming units for the FS, RFS, and control groups were 6.75, 105, and 375, respectively. In the penetration test, fresh frog skin showed to be a bacterial resistant dressing. The results revealed that the rate of wound closure in the experimental groups significantly was accelerated in comparison with that in the control group. Conclusions: Our results demonstrated the antimicrobial properties of frog skin as a wound dressing, which has antimicrobial effects per se. This biological dressing shows promise as an effective biological wound dressing insofar as not only is it capable of resisting microbes and accelerating wound healing but also it is cost-effective and easy to use. PMID:26468364

Simulation and Optimization of Vacuum Swing Adsorption Units for Spacesuit Carbon Dioxide and Humidity Control

NASA Technical Reports Server (NTRS)

Swickrath, Michael J.; Anderson, Molly; McMillin, Summer; Broerman, Craig

2010-01-01

Controlling carbon dioxide (CO2) and humidity levels in a spacesuit is critical to ensuring both the safety and comfort of an astronaut during extra-vehicular activity (EVA). Traditionally, this has been accomplished utilizing non-regenerative lithium hydroxide (LiOH) or regenerative metal oxide (MetOx) canisters which pose a significant weight burden. Although such technology enables air revitalization, the volume requirements to store the waste canisters as well as the mass to transport multiple units become prohibitive as mission durations increase. Consequently, motivation exists toward developing a fully regenerative technology for environmental control. The application of solid amine materials with vacuum swing adsorption technology has shown the capacity to control CO2 and concomitantly manage humidity levels through a fully regenerative cycle eliminating mission constraints imposed with non-regenerative technologies. Experimental results for full-size and sub-scale test articles have been collected and are described herein. In order to accelerate the developmental efforts, an axially-dispersed plug ow model with an accompanying energy balance has been established and correlated with the experimental data. The experimental and simulation results display good agreement for a variety of ow rates (110-170 SLM), replicated metabolic challenges (100-590 Watts), and atmosphere pressures under consideration for the spacesuit (248 and 760 mm Hg). The relationship between swing adsorption cycles for an outlet criterion of 6.0 mm Hg of CO2 partial pressure has been established for each metabolic challenge. In addition, variable metabolic profiles were imposed on the test articles in order to assess the ability of the technology to transition to new operational constraints. The advent of the model provides the capacity to apply computer-aided engineering practices to support the ongoing efforts to optimize and mature this technology for future application to space exploration.

Experimental Investigation of Eccentricity Ratio, Friction, and Oil Flow of Short Journal Bearings

NASA Technical Reports Server (NTRS)

Dubois, G B; Ocvirk, F W

1952-01-01

An experimental investigation was conducted to obtain performance data on bearings of length-diameter ratios of 1, 1/2, and 1/4 for comparison with theoretical curves. A 1.375-inch-diameter bearing was tested at speeds up to 6000 rpm and with unit loads from 0 to 900 pounds per square inch. Experimental data for eccentricity ratio and friction followed single lines when plotted against a theoretically derived capacity number, which is equal to Sommerfeld number times the square of the length-diameter ratio. The form of the capacity number indicates that under certain conditions the eccentricity ratio is theoretically independent of bearing diameter. A method of plotting oil flow data as a single line is shown. Methods are also discussed for approximating a maximum bearing temperature and evaluating the effect of deflection or misalignment on the eccentricity ratio at the ends of the bearings.

Instructional Efficiency of Changing Cognitive Load in an Out-of-School Laboratory

NASA Astrophysics Data System (ADS)

Scharfenberg, Franz-Josef; Bogner, Franz X.

2010-04-01

Our research objective focused on monitoring students' mental effort and cognitive achievement to unveil potential effects of an instructional change in an out-of-school laboratory offering gene technology modules. Altogether, 231 students (12th graders) attended our day-long hands-on module. Within a quasi-experimental design, a treatment group followed the newly developed two-step approach derived from cognitive load theory while a control group applied experimentation in a conventional one-step mode. The difference consisted of additional focused discussions combined with noting students' ideas (Step 1) prior to starting any experimental procedure (Step 2). We monitored mental effort (nine times during the teaching unit) and cognitive achievement (in a pre-post-design with follow-up test). The treatment demonstrated a change in instructional efficiency (by combining mental effort and cognitive achievement data), especially for intrinsically high-loaded students. Conclusions for optimizing individual cognitive load in science teaching were drawn.

Continuous microalgal cultivation in a laboratory-scale photobioreactor under seasonal day-night irradiation: experiments and simulation.

PubMed

Bertucco, Alberto; Beraldi, Mariaelena; Sforza, Eleonora

2014-08-01

In this work, the production of Scenedesmus obliquus in a continuous flat-plate laboratory-scale photobioreactor (PBR) under alternated day-night cycles was tested both experimentally and theoretically. Variation of light intensity according to the four seasons of the year were simulated experimentally by a tunable LED lamp, and effects on microalgal growth and productivity were measured to evaluate the conversion efficiency of light energy into biomass during the different seasons. These results were used to validate a mathematical model for algae growth that can be applied to simulate a large-scale production unit, carried out in a flat-plate PBR of similar geometry. The cellular concentration in the PBR was calculated in both steady-state and transient conditions, and the value of the maintenance kinetic term was correlated to experimental profiles. The relevance of this parameter was finally outlined.

Developments in Screening Tests and Strategies for Colorectal Cancer

PubMed Central

Sovich, Justin L.; Sartor, Zachary

2015-01-01

Background. Worldwide, colorectal cancer (CRC) is the third most common cancer in men and second most common in women. It is the fourth most common cause of cancer mortality. In the United States, CRC is the third most common cause of cancer and second most common cause of cancer mortality. Incidence and mortality rates have steadily fallen, primarily due to widespread screening. Methods. We conducted keyword searches on PubMed in four categories of CRC screening: stool, endoscopic, radiologic, and serum, as well as news searches in Medscape and Google News. Results. Colonoscopy is the gold standard for CRC screening and the most common method in the United States. Technological improvements continue to be made, including the promising “third-eye retroscope.” Fecal occult blood remains widely used, particularly outside the United States. The first at-home screen, a fecal DNA screen, has also recently been approved. Radiological methods are effective but seldom used due to cost and other factors. Serum tests are largely experimental, although at least one is moving closer to market. Conclusions. Colonoscopy is likely to remain the most popular screening modality for the immediate future, although its shortcomings will continue to spur innovation in a variety of modalities. PMID:26504799

The effect of visiting surgical patients in the postanesthesia care unit on family members' anxiety: a prospective quasi-experimental study.

PubMed

Patelarou, Athina; Melidoniotis, Evangelos; Sgouraki, Maria; Karatzi, Maria; Souvatzis, Xenia

2014-06-01

Surgical procedures pose stressful events for patients and their family members. The main purpose of this study was to determine if visiting patients in the postanesthesia care unit (PACU) would reduce the anxiety levels of Greek patients' family members. A prospective study with a one-group quasi-experimental pretest/post-test design was used. Situational anxiety of surgical patients' relatives was assessed using the state subscale of the State-Trait Anxiety Inventory (STAI; Greek validation) at the beginning of the surgical procedure and again after their visitation of patients in the PACU. STAI scores were significantly higher preoperatively (57 [23-80]) than postoperatively (51 [21-77]; P=.000008). Clinically significant levels of anxiety were present in 76% and 58% of the participants, pre- and postoperatively, respectively. Although postoperative STAI scores were reduced, family visitation in the PACU did not sufficiently reduce the anxiety of Greek family members to clinically acceptable levels. Copyright © 2014 American Society of PeriAnesthesia Nurses. Published by Elsevier Inc. All rights reserved.

Low cost solar array project: Experimental process system development unit for producing semiconductor-grade silicon using the silane-to-silicon process

NASA Technical Reports Server (NTRS)

1981-01-01

The results of the free space reactor experimental work are summarized. Overall, the objectives were achieved and the unit can be confidently scaled to the EPSDU size based on the experimental work and supporting theoretical analyses. The piping and instrumentation of the fluidized bed reactor was completed.

Experimental Model School Unit. Application for Continuation Grant. P.L. 89-10 ESEA, Title III.

ERIC Educational Resources Information Center

Charlotte-Mecklenburg Public Schools, Charlotte, NC.

This application for continuation of an ESEA, Title III, grant to the Charlotte-Mecklenburg, N.C., Schools' Experimental Model School Unit (a senior high school and its two junior high and six elementary feeder schools with a program of research, experimentation, innovation, and dissemination designed to act as a catalyst for curriculum,…

The use of concrete learning objects taken from the history of mathematics in mathematics education

NASA Astrophysics Data System (ADS)

Bütüner, Suphi Önder

2016-11-01

This study aimed to reveal the effects of teaching with concrete learning objects taken from the history of mathematics on student achievement. Being a quasi-experimental study, it was conducted with two grade 8 classes in a secondary school located in Trabzon. The experimental group consisted of 27 students and the control group consisted of 25. Data were collected by using worksheets, an achievement exam and written opinion forms. The data from the achievement exam were analysed by using the Mann-Whitney U-test while the data from written opinion forms were analysed through content analysis. The Mann-Whitney U-test results showed a significant difference between the mean ranks of the experimental and control groups in favour of the former. Findings from the written opinion forms suggested that the students found the activities to be instructive and fun, enjoyed using concrete models in their classes, and learned from discovering the rules. It was also found that students had previously not engaged in similar activities and had only experienced the history of mathematics through the life stories and works of mathematicians and the representation of ancient numbers at the beginning of each unit.

X-34 Experimental Aeroheating at Mach 6 and 10

NASA Technical Reports Server (NTRS)

Berry, Scott A.; Horvath, Thomas J.; DiFulvio, Michael; Glass, Christopher; Merski, N. Ronald

1998-01-01

Critical technologies are being developed to support the goals of the NASA Office of Aeronautics and Space Transportation Technology Access to Space initiative for next-generation reusable space transportation systems. From the perspective of aerothermodynamic performance throughout the flight trajectory, the Reusable Launch Vehicle program incorporates conceptual analysis, ground-based testing, and computational fluid dynamics to provide flyable suborbital flight demonstrator vehicles. This report provides an overview of the hypersonic aeroheating wind tunnel test program conducted at the NASA Langley Research Center in support of one of these vehicles, the X-34 small reusable technology demonstrator program. Global surface heat transfer images, surface streamline patterns, and shock shapes were measured on 0.0153- and 0.0183-scale models of proposed X-34 flight vehicles at Mach 6 and 10 in air. The primary parametrics that were investigated include angles-of-attack from 0 to 35 deg. and freestream unit Reynolds numbers from 0.5 to 8 million per foot (which was sufficient to produce laminar, transitional, and turbulent heating data), both with and without control surface deflections. Comparisons of the experimental data to computational predictions are included, along with a discussion of the implications of some of the experimental flow features for the flight vehicle.

Development of the Plant Growth Facility for Use in the Shuttle Middeck and Test Units for Ground-Based Experiments

NASA Technical Reports Server (NTRS)

Chapman, David K.; Wells, H. William

1996-01-01

The plant growth facility (PGF), currently under development as a Space Shuttle middeck facility for the support of research on higher plants in microgravity, is presented. The PGF provides controlled fluorescent lighting and the active control of temperature, relative humidity and CO2 concentration. These parameters are designed to be centrally controlled by a dedicated microprocessor. The status of the experiment can be displayed for onboard analysis, and will be automatically archived for post-flight analysis. The facility is designed to operate for 15 days and will provide air filtration to remove ethylene and trace organics with replaceable potassium permanganate filters. Similar ground units will be available for pre-flight experimentation.

Recent results on qualification of the RITA components for the ARTEMIS satellite

NASA Astrophysics Data System (ADS)

Bassner, H.; Berg, H.-P.; Kukies, R.

1992-07-01

An improved version of RITA, a radiofrequency ion thruster assembly, is planned to be used as part of the Ion Propulsion Package of an experimental communication satellite, ARTEMIS, now under development in Europe. The Ion Propulsion Package will be used to perform north/south stationkeeping as a responsible subsystem during 10 years of satellite operation. For this purpose, the thrust level of RITA has been increased from 10 to 15 mN. A complete redesign of the Power Supply and Control Unit will simplify the control of the thruster and neutralizer and decrease the number of parts in this electronic unit. The RF generator has been redesigned using latest technology. Results of lifetime and function tests are reported.

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

Schaeffel, J.A.; Mullinix, B.R.; Ranson, W.F.

An experimental technique to simulate and evaluate the effects of high concentrations of x-rays resulting from a nuclear detonation on missile structures is presented. Data from 34 tests are included to demonstrate the technique. The effects of variations in the foil thickness, capacitor voltage, and plate thickness on the total impulse and maximum strain in the structure were determined. The experimental technique utilizes a high energy capacitor discharge unit to explode an aluminum foil on the surface of the structure. The structural response is evaluated by optical methods using the grid slope deflection method. The fringe patterns were recorded usingmore » a high-speed framing camera. The data were digitized using an optical comparator with an x-y table. The analysis was performed on a CDC 6600 computer.« less

Use of biogas for cogeneration of heat and electricity for local application: performance evaluation of an engine power generator and a sludge thermal dryer.

PubMed

Lobato, L C S; Chernicharo, C A L; Pujatti, F J P; Martins, O M; Melo, G C B; Recio, A A R

2013-01-01

A small unit of cogeneration of energy and heat was tested at the Centre for Research and Training on Sanitation UFMG/COPASA - CePTS, located at the Arrudas Sewage Treatment Plant, in Belo Horizonte, Minas Gerais, Brazil. The unit consisted of an engine power generator adapted to run on biogas, a thermal dryer prototype and other peripherals (compressor, biogas storage tank, air blower, etc.). The heat from engine power generator exhaust gases was directed towards the thermal dryer prototype to dry the sludge and disinfect it. The results showed that the experimental apparatus is self-sufficient in electricity, even producing a surplus, available for other uses. The tests of drying and disinfection of sludge lasted 7 h, leading to an increase in solids content from 4 to 8% (50% reduction in sludge volume). Although the drying of sludge was not possible (only thickening was achieved), the disinfection process proved very effective, enabling the complete inactivation of helminth eggs.

An investigation on wireless sensors for asset management and health monitoring of civil structures

NASA Astrophysics Data System (ADS)

Furkan, Mustafa; Mao, Qiang; Mazzotti, Matteo; DeVitis, John; Sumitro, S. Paul; Faridazar, Fred; Aktan, A. Emin; Moon, Franklin; Bartoli, Ivan

2016-04-01

Application of wireless sensors and sensor networks for Structural Health Monitoring has been investigated for a long time. Key limitations for practical use are energy requirements, connectivity, and integration with existing systems. Current sensors and sensor networks mainly rely on wired connectivity for communication and external power source for energy. This paper presents a suite of wireless sensors that are low-cost, maintenance free, rugged, and have long service life. The majority of the sensors considered were designed by transforming existing, proven, and robust wired sensors into wireless units. In this study, the wireless sensors were tested in laboratory conditions for calibration and evaluation along with wired sensors. The experimental results were also compared to theoretical results. The tests mostly show satisfactory performance of the wireless units. This work is part of a broader Federal Highway Administration sponsored project intended to ultimately validate a wireless sensing system on a real, operating structure to account for all the uncertainties, environmental conditions and operational variability that are encountered in the field.

Density Functional Theory Calculation of pKa's of Thiols in Aqueous Solution Using Explicit Water Molecules and the Polarizable Continuum Model.

PubMed

Thapa, Bishnu; Schlegel, H Bernhard

2016-07-21

The pKa's of substituted thiols are important for understanding their properties and reactivities in applications in chemistry, biochemistry, and material chemistry. For a collection of 175 different density functionals and the SMD implicit solvation model, the average errors in the calculated pKa's of methanethiol and ethanethiol are almost 10 pKa units higher than for imidazole. A test set of 45 substituted thiols with pKa's ranging from 4 to 12 has been used to assess the performance of 8 functionals with 3 different basis sets. As expected, the basis set needs to include polarization functions on the hydrogens and diffuse functions on the heavy atoms. Solvent cavity scaling was ineffective in correcting the errors in the calculated pKa's. Inclusion of an explicit water molecule that is hydrogen bonded with the H of the thiol group (in neutral) or S(-) (in thiolates) lowers error by an average of 3.5 pKa units. With one explicit water and the SMD solvation model, pKa's calculated with the M06-2X, PBEPBE, BP86, and LC-BLYP functionals are found to deviate from the experimental values by about 1.5-2.0 pKa units whereas pKa's with the B3LYP, ωB97XD and PBEVWN5 functionals are still in error by more than 3 pKa units. The inclusion of three explicit water molecules lowers the calculated pKa further by about 4.5 pKa units. With the B3LYP and ωB97XD functionals, the calculated pKa's are within one unit of the experimental values whereas most other functionals used in this study underestimate the pKa's. This study shows that the ωB97XD functional with the 6-31+G(d,p) and 6-311++G(d,p) basis sets, and the SMD solvation model with three explicit water molecules hydrogen bonded to the sulfur produces the best result for the test set (average error -0.11 ± 0.50 and +0.15 ± 0.58, respectively). The B3LYP functional also performs well (average error -1.11 ± 0.82 and -0.78 ± 0.79, respectively).

United States Department of Energy solar receiver technology development

NASA Astrophysics Data System (ADS)

Klimas, P. C.; Diver, R. B.; Chavez, J. M.

The United States Department of Energy (DOE), through Sandia National Laboratories, has been conducting a Solar Thermal Receiver Technology Development Program, which maintains a balance between analytical modeling, bench and small scale testing, and experimentation conducted at scales representative of commercially-sized equipment. Central receiver activities emphasize molten salt-based systems on large scales and volumetric devices in the modeling and small scale testing. These receivers are expected to be utilized in solar power plants rated between 100 and 200 MW. Distributed receiver research focuses on liquid metal refluxing devices. These are intended to mate parabolic dish concentrators with Stirling cycle engines in the 5 to 25 kW(sub e) power range. The effort in the area of volumetric receivers is less intensive and highly cooperative in nature. A ceramic foam absorber of Sandia design was successfully tested on the 200 kW(sub t) test bed at Plataforma Solar during 1989. Material integrity during the approximately 90-test series was excellent. Significant progress has been made with parabolic dish concentrator-mounted receivers using liquid metals (sodium or a potassium/sodium mixture) as heat transport media. Sandia has successfully solar-tested a pool boiling reflux receiver sized to power a 25 kW Stirling engine. Boiling stability and transient operation were both excellent. This document describes these activities in detail and will outline plans for future development.

Preliminary lithogeochemical map showing near-surface rock types in the Chesapeake Bay watershed, Virginia and Maryland

USGS Publications Warehouse

Peper, John D.; McCartan, Lucy; Horton, J. Wright; Reddy, James E.

2001-01-01

This preliminary experimental lithogeochemical map shows the distribution of rock types in the Virginia and Maryland parts of the Chesapeake Bay watershed. The map was produced digitally by classifying geologic-map units according to composition, mineralogy, and texture; rather than by age and stratigraphic relationships as shown on traditional geologic maps. This map differs from most lithologic maps in that the lithogeochemical unit classification distinguishes those rock units having key water-reactive minerals that may induce acid neutralization, or reduction, of hosted water at the weathering interface. The validity of these rock units, however, is independent of water chemistry, because the rock units are derived from geologic maps and rock descriptions. Areas of high soil carbon content, and sulfide metal deposits are also shown. Water-reactive minerals and their weathering reactions yield five lithogeochemical unit classes: 1) carbonate rock and calcareous rocks and sediments, the most acid-neutralizing; 2)carbonaceous-sulfidic rocks and sediments, oxygen-depleting and reducing; 3) quartzofeldspathic rocks and siliciclastic sediments, relatively weakly reactive with water; 4) mafic silicate rocks/sediments, oxygen consuming and high solute-load delivering; and, 5) the rarer calcareous-sulfidic (carbonaceous) rocks, neutralizing and reducing. Earlier studies in some parts of the map area have related solute loads in ground and stream waters to some aspects of bedrock lithology. More recent preliminary tests of relationships between four of the classes of mapped lithogeochemical units and ground water chemistry, in the Mid-Atlantic area using this map, have focused on and verified the nitrate-reducing and acid-neutralizing properties of some bedrock and unconsolidated aquifer rock types. Sulfide mineral deposits and their mine-tailings effects on waters are beginning to be studied by others. Additional testing of relationships among the lithogeochemical units and aspects of ground and surface water chemistry could help to refine the lithogeochemical classification, and this map. The testing could also improve the usefulness of the map for assessing aquifer reactivity and the transport properties of reactive contaminants such as acid rain, and nitrate from agricultural sources, in the Chesapeake Bay watershed.

The theory of granular packings for coarse soils

NASA Astrophysics Data System (ADS)

Yanqui, Calixtro

2013-06-01

Coarse soils are substances made of grains of different shape, size and orientation. In this paper, new massive-measurable grain indexes are defined to develop a simple and systematic theory for the ideal packing of grains. First, a linear relationship between an assemblage of monodisperse spheres and an assemblage of polydisperse grains is deduced. Then, a general formula for the porosity of linearly ordered packings of spheres in contact is settled down by the appropriated choosing of eight neighboring spheres located at the vertices of the unit parallelepiped. The porosity of axisymmetric packings of grains, related to sand piles and axisymmetric compression tests, is proposed to be determined averaging the respective linear parameters. Since they can be tested experimentally, porosities of the densest state and the loosest state of a granular soil can be used to verify the accuracy of the present theory. Diagrams for these extreme quantities show a good agreement between the theoretical lines and the experimental data, no matter the dependency on the protocols and mineral composition.

Development of a standardized and safe airborne antibacterial assay, and its evaluation on antibacterial biomimetic model surfaces.

PubMed

Al-Ahmad, Ali; Zou, Peng; Solarte, Diana Lorena Guevara; Hellwig, Elmar; Steinberg, Thorsten; Lienkamp, Karen

2014-01-01

Bacterial infection of biomaterials is a major concern in medicine, and different kinds of antimicrobial biomaterial have been developed to deal with this problem. To test the antimicrobial performance of these biomaterials, the airborne bacterial assay is used, which involves the formation of biohazardous bacterial aerosols. We here describe a new experimental set-up which allows safe handling of such pathogenic aerosols, and standardizes critical parameters of this otherwise intractable and strongly user-dependent assay. With this new method, reproducible, thorough antimicrobial data (number of colony forming units and live-dead-stain) was obtained. Poly(oxonorbornene)-based Synthetic Mimics of Antimicrobial Peptides (SMAMPs) were used as antimicrobial test samples. The assay was able to differentiate even between subtle sample differences, such as different sample thicknesses. With this new set-up, the airborne bacterial assay was thus established as a useful, reliable, and realistic experimental method to simulate the contamination of biomaterials with bacteria, for example in an intraoperative setting.

Enabling CSPA Operations Through Pilot Involvement in Longitudinal Approach Spacing

NASA Technical Reports Server (NTRS)

Battiste, Vernol (Technical Monitor); Pritchett, Amy

2003-01-01

Several major airports around the United States have, or plan to have, closely-spaced parallel runways. This project complemented current and previous research by examining the pilots ability to control their position longitudinally within their approach stream.This project s results considered spacing for separation from potential positions of wake vortices from the parallel approach. This preventive function could enable CSPA operations to very closely spaced runways. This work also considered how pilot involvement in longitudinal spacing could allow for more efficient traffic flow, by allowing pilots to keep their aircraft within tighter arrival slots then air traffic control (ATC) might be able to establish, and by maintaining space within the arrival stream for corresponding departure slots. To this end, this project conducted several research studies providing an analytic and computational basis for calculating appropriate aircraft spacings, experimental results from a piloted flight simulator test, and an experimental testbed for future simulator tests. The following sections summarize the results of these three efforts.

IMAGE-GUIDED TREATMENT USING AN X-RAY THERAPY UNIT AND GOLD NANOPARTICLES: TEST OF CONCEPT.

PubMed

Le Loirec, Cindy; Chambellan, Dominique; Tisseur, David

2016-06-01

Gold nanoparticles (GNPs) have the potential to enhance the radiation dose locally in conjunction with kV X-rays used for radiation therapy. As for other radiotherapy modalities, the absorbed dose needs to be controlled. To do that, it is an advantage to know the distribution of GNPs. However, no effective imaging tool exists to determine the GNP distribution in vivo. Various approaches have been proposed to determine the concentration of GNPs and its distribution in a tumour and in other organs and tissues. X-ray fluorescence computed tomography (XFCT) is a promising imaging technique to do that. A new experimental device based on the XFCT technique allowing the in vivo control of GNP radiotherapy treatments is proposed. As a test of concept, experimental acquisitions and Monte Carlo simulations were performed to determine the performance that a XFCT detector has to fulfil. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

[A Study on the Cognitive Learning Effectiveness of Scenario-Based Concept Mapping in a Neurological Nursing Course].

PubMed

Pan, Hui-Ching; Hsieh, Suh-Ing; Hsu, Li-Ling

2015-12-01

The multiple levels of knowledge related to the neurological system deter many students from pursuing studies on this topic. Thus, in facing complicated and uncertain medical circumstances, nursing students have diffi-culty adjusting and using basic neurological-nursing knowledge and skills. Scenario-based concept-mapping teaching has been shown to promote the integration of complicated data, clarify related concepts, and increase the effectiveness of cognitive learning. To investigate the effect on the neurological-nursing cognition and learning attitude of nursing students of a scenario-based concept-mapping strategy that was integrated into the neurological nursing unit of a medical and surgical nursing course. This quasi-experimental study used experimental and control groups and a pre-test / post-test design. Sopho-more (2nd year) students in a four-year program at a university of science and technology in Taiwan were convenience sampled using cluster randomization that was run under SPSS 17.0. Concept-mapping lessons were used as the intervention for the experimental group. The control group followed traditional lesson plans only. The cognitive learning outcome was measured using the neurological nursing-learning examination. Both concept-mapping and traditional lessons significantly improved post-test neurological nursing learning scores (p < .001), with no significant difference between the two groups (p = .51). The post-test feedback from the control group mentioned that too much content was taught and that difficulties were experienced in understanding mechanisms and in absorbing knowledge. In contrast, the experimental group held a significantly more positive perspective and learning attitude with regard to the teaching material. Furthermore, a significant number in the experimental group expressed the desire to add more lessons on anatomy, physiology, and pathology. These results indicate that this intervention strategy may help change the widespread fear and refusal of nursing students with regard to neurological lessons and may facilitate interest and positively affect learning in this important subject area. Integrating the concept-mapping strategy and traditional clinical-case lessons into neurological nursing lessons holds the potential to increase post-test scores significantly. Concept mapping helped those in the experimental group adopt views and attitudes toward learning the teaching material that were more positive than those held by their control-group peers. In addition, while 59% of the experimental group and 49% of the control group submitted opinions related to learning attitude in the open-ended questions, positive feedback was greater in the experimental group than in the control group.

Plasma core reactor simulations using RF uranium seeded argon discharges

NASA Technical Reports Server (NTRS)

Roman, W. C.

1975-01-01

An experimental investigation was conducted using the United Technologies Research Center (UTRC) 80 kW and 1.2 MW RF induction heater systems to aid in developing the technology necessary for designing a self-critical fissioning uranium plasma core reactor (PCR). A nonfissioning, steady-state RF-heated argon plasma seeded with pure uranium hexafluoride (UF6) was used. An overall objective was to achieve maximum confinement of uranium vapor within the plasma while simultaneously minimizing the uranium compound wall deposition. Exploratory tests were conducted using the 80 kW RF induction heater with the test chamber at approximately atmospheric pressure and discharge power levels on the order of 10 kW. Four different test chamber flow configurations were tested to permit selection of the configuration offering the best confinement characteristics for subsequent tests at higher pressure and power in the 1.2 MW RF induction heater facility.

Experimental Characterization of Gas Turbine Emissions at Simulated Flight Altitude Conditions

NASA Technical Reports Server (NTRS)

Howard, R. P.; Wormhoudt, J. C.; Whitefield, P. D.

1996-01-01

NASA's Atmospheric Effects of Aviation Project (AEAP) is developing a scientific basis for assessment of the atmospheric impact of subsonic and supersonic aviation. A primary goal is to assist assessments of United Nations scientific organizations and hence, consideration of emissions standards by the International Civil Aviation Organization (ICAO). Engine tests have been conducted at AEDC to fulfill the need of AEAP. The purpose of these tests is to obtain a comprehensive database to be used for supplying critical information to the atmospheric research community. It includes: (1) simulated sea-level-static test data as well as simulated altitude data; and (2) intrusive (extractive probe) data as well as non-intrusive (optical techniques) data. A commercial-type bypass engine with aviation fuel was used in this test series. The test matrix was set by parametrically selecting the temperature, pressure, and flow rate at sea-level-static and different altitudes to obtain a parametric set of data.

The antimicrobial effect of spice-based marinades against Campylobacter jejuni on contaminated fresh broiler wings.

PubMed

Zakarienė, Gintarė; Rokaitytė, Anita; Ramonaitė, Sigita; Novoslavskij, Aleksandr; Mulkytė, Kristina; Zaborskienė, Gintarė; Malakauskas, Mindaugas

2015-03-01

The antimicrobial effect of spice-based marinades against Campylobacter jejuni on inoculated fresh broiler wings was investigated. Experiments were carried out with 1 strain of C. jejuni and 6 marinades. Four experimental marinades were composed for the study and contained spices (thyme, rosemary, basil, marjoram, and so on) and different combination of bioactive compounds. Two marinades were commercial and contained spices (black pepper, sweet red pepper, and so on) and chemical additives (monosodium glutamate, sodium diacetate, calcium lactate), 1 commercial marinade was also enriched with bioactive compounds (linalool, cinnamaldehyde, lactic acid). Total aerobic bacterial count was examined to estimate the possible effect of tested marinades on the shelf-life of marinated broiler wings. Study revealed that thyme-based marinade was the most effective against C. jejuni on broiler wings and reduced the numbers of campylobacters by 1.04 log colony forming unit (CFU)/g (P ≤ 0.05) during storage for 168 h at 4 °C temperature. Moreover, it was more effective against C. jejuni than commercial marinade with 0.47 log CFU/g (P ≤ 0.05) reduction effect. Both experimental and commercial marinades had very similar effect on the total aerobic bacterial count. Although experimental and commercial marinades had different effect on pH of broiler wings, this parameter did not show a major impact on the antimicrobial effect of tested marinades (P ≥ 0.05). Our study shows that experimental natural thyme-based marinade can reduce numbers of C. jejuni more effectively than tested commercial marinades. © 2015 Institute of Food Technologists®

Quantitative inhibition of soil C and N cycling by ectomycorrhizal fungi under field condition

NASA Astrophysics Data System (ADS)

Averill, C.; Hawkes, C.

2014-12-01

Ectomycorrhizal (ECM) ecosystems store more carbon than non-ectomycorrhizal ecosystems at global scale. Recent theoretical and empirical work suggests the presence of ECM fungi allows plants to compete directly with decomposers for soil nitrogen (N) via exo-enzyme synthesis. Experimental ECM exclusion often results in a release from competition of saprotrophic decomposers, allowing for increased C-degrading enzyme production, increased microbial biomass, and eventually declines in soil C stocks. Our knowledge of this phenomenon is limited, however, to the presence or absence of ECM fungi. It remains unknown if competitive repression of saprotrophic microbes and soil C cycling by ECM fungi varies with ECM abundance. This is particularly relevant to global change experiments when manipulations alter plant C allocation to ECM symbionts. To test if variation in ECM abundance alters the competitive inhibition of saprotrophic soil microbes (quantitative inhibition) we established experimental ECM exclusion treatments along an ECM abundance gradient. We dug trenches to experimentally exclude ECM fungi, allowing us to test for competitive release of soil saprotrophs from competition. To control for disturbance we placed in-growth bags both inside and outside of trenches. Consistent with the quantitative inhibition hypothesis, sites with more ECM fungi had significantly less microbial biomass per unit soil C and lower rates of N mineralization. Consistent with a release from competition, C-degrading enzyme activities were higher and gross proteolytic rates were lower per unit microbial biomass inside compared to outside trenches. We interpret this to reflect increased microbial investment in C-acquisition and decreased investment in N-acquisition in the absence of ECM fungi. Furthermore, the increase in C-degrading enzymes per unit microbial biomass was significantly greater in sites with the most abundant ECM fungi. Based on these results, ECM-saprotroph competition does appear to slow soil C cycling and the effect is quantitative. Soil C cycling is at least partly controlled by interactions between ECM fungi and soil saprotrophs. Environmental change that alters ECM abundance may thus alter soil C stocks by ameliorating or exacerbating plant-decomposer competition for nitrogen.

Experimental Analysis of the Vorticity and Turbulent Flow Dynamics of a Pitching Airfoil at Realistic Flight Conditions

DTIC Science & Technology

2007-08-31

Element type Hex, independent meshing, Linear 3D stress Hex, independent meshing, Linear 3D stress 1 English Units were used in ABAQUS The NACA...Flow Freestream Condition Instrumentation Test section conditions were measured using a Druck DPI 203 digital pressure gage and an Omega Model 199...temperature gage. The Druck pressure gage measures the set dynamic pressure within 0.08%± of full scale, and the Omega thermometer is accurate to

Development of burners for afterburning chambers of heat-recovery boilers at cogeneration stations equipped with combined-cycle plants

NASA Astrophysics Data System (ADS)

Khomenok, L. A.

2007-09-01

Problems related to efficient afterburning of fuel in the medium of gas-turbine unit exhaust gases, as well as new design arrangements of gas-jet burners used in the chambers for afterburning fuel in heat-recovery boilers at cogeneration stations equipped with combined-cycle plants, are considered. Results obtained from comparative experimental investigations of different gas-jet flame stabilizers at a test facility are presented, and the advantages of jet-ejector stabilizers are demonstrated.

In-plant testing of membranes to treat electroplating wastewater

NASA Technical Reports Server (NTRS)

Shah, D. B.; Talu, Orhan

1995-01-01

This is the final report submitted for the work performed under the NASA Cooperative Agreement NCC3-301 for the project entitled 'In-Plant Testing of Membranes To Treat Electroplating Waste water'. The main objective of the research project was to determine if the crosslinked polyacrylic acid salt films developed by NASA scientists could be used for heavy metal removal from the wastewater generated by the metals-finishing or electroplating industry. A variety of tasks identified in the original proposal were completed. These included: (1) analysis of our industrial partner Aetna Plating's zinc electroplating process and its wastewater treatment needs for zinc removal; (2) design and construction of a laboratory-scale unit to continuously supply and remove the ion exchange films from the zinc wastewater; (3) performance of a series of runs on such a unit to determine its operating characteristics; and (4) design of a prototype unit for use at the industrial site. In addition, there were a number of tasks that had not been identified in the original proposal but were later judged to be necessary for the successful completion of the project. These were: (1) batch equilibrium and kinetic experiments with analysis of the experimental results to accurately determine the equilibrium and kinetic parameters for the ion exchange films; (2 ) simulation studies for proper design of the prototype unit; and (3) preliminary runs to exchange the films from H form to Calcium form.

A Novel Analysis Method for Paired-Sample Microbial Ecology Experiments.

PubMed

Olesen, Scott W; Vora, Suhani; Techtmann, Stephen M; Fortney, Julian L; Bastidas-Oyanedel, Juan R; Rodríguez, Jorge; Hazen, Terry C; Alm, Eric J

2016-01-01

Many microbial ecology experiments use sequencing data to measure a community's response to an experimental treatment. In a common experimental design, two units, one control and one experimental, are sampled before and after the treatment is applied to the experimental unit. The four resulting samples contain information about the dynamics of organisms that respond to the treatment, but there are no analytical methods designed to extract exactly this type of information from this configuration of samples. Here we present an analytical method specifically designed to visualize and generate hypotheses about microbial community dynamics in experiments that have paired samples and few or no replicates. The method is based on the Poisson lognormal distribution, long studied in macroecology, which we found accurately models the abundance distribution of taxa counts from 16S rRNA surveys. To demonstrate the method's validity and potential, we analyzed an experiment that measured the effect of crude oil on ocean microbial communities in microcosm. Our method identified known oil degraders as well as two clades, Maricurvus and Rhodobacteraceae, that responded to amendment with oil but do not include known oil degraders. Our approach is sensitive to organisms that increased in abundance only in the experimental unit but less sensitive to organisms that increased in both control and experimental units, thus mitigating the role of "bottle effects".

An End-To-End Test of A Simulated Nuclear Electric Propulsion System

NASA Technical Reports Server (NTRS)

VanDyke, Melissa; Hrbud, Ivana; Goddfellow, Keith; Rodgers, Stephen L. (Technical Monitor)

2002-01-01

The Safe Affordable Fission Engine (SAFE) test series addresses Phase I Space Fission Systems issues in it particular non-nuclear testing and system integration issues leading to the testing and non-nuclear demonstration of a 400-kW fully integrated flight unit. The first part of the SAFE 30 test series demonstrated operation of the simulated nuclear core and heat pipe system. Experimental data acquired in a number of different test scenarios will validate existing computational models, demonstrated system flexibility (fast start-ups, multiple start-ups/shut downs), simulate predictable failure modes and operating environments. The objective of the second part is to demonstrate an integrated propulsion system consisting of a core, conversion system and a thruster where the system converts thermal heat into jet power. This end-to-end system demonstration sets a precedent for ground testing of nuclear electric propulsion systems. The paper describes the SAFE 30 end-to-end system demonstration and its subsystems.

Dynamic neural network models of the premotoneuronal circuitry controlling wrist movements in primates.

PubMed

Maier, M A; Shupe, L E; Fetz, E E

2005-10-01

Dynamic recurrent neural networks were derived to simulate neuronal populations generating bidirectional wrist movements in the monkey. The models incorporate anatomical connections of cortical and rubral neurons, muscle afferents, segmental interneurons and motoneurons; they also incorporate the response profiles of four populations of neurons observed in behaving monkeys. The networks were derived by gradient descent algorithms to generate the eight characteristic patterns of motor unit activations observed during alternating flexion-extension wrist movements. The resulting model generated the appropriate input-output transforms and developed connection strengths resembling those in physiological pathways. We found that this network could be further trained to simulate additional tasks, such as experimentally observed reflex responses to limb perturbations that stretched or shortened the active muscles, and scaling of response amplitudes in proportion to inputs. In the final comprehensive network, motor units are driven by the combined activity of cortical, rubral, spinal and afferent units during step tracking and perturbations. The model displayed many emergent properties corresponding to physiological characteristics. The resulting neural network provides a working model of premotoneuronal circuitry and elucidates the neural mechanisms controlling motoneuron activity. It also predicts several features to be experimentally tested, for example the consequences of eliminating inhibitory connections in cortex and red nucleus. It also reveals that co-contraction can be achieved by simultaneous activation of the flexor and extensor circuits without invoking features specific to co-contraction.

Performance Characterization and Simulation of Amine-Based Vacuum Swing Sorption Units for Spacesuit Carbon Dioxide and Humidity Control

NASA Technical Reports Server (NTRS)

Swickrath, Michael J.; Watts, Carly; Anderson, Molly; McMillin, Summer; Broerman, Craig; Colunga, Aaron; Vogel, Matthew

2012-01-01

Controlling carbon dioxide (CO2) and water (H2O) vapor concentrations in a space suit is critical to ensuring an astronauts safety, comfort, and capability to perform extra-vehicular activity (EVA) tasks. Historically, this has been accomplished using lithium hydroxide (LiOH) and metal oxide (MetOx) canisters. Lithium hydroxide is a consumable material that requires priming with water before it becomes effective at removing carbon dioxide. MetOx is regenerable through a power-intensive thermal cycle but is significantly heavier on a volume basis than LiOH. As an alternative, amine-based vacuum swing beds are under aggressive development for EVA applications. The vacuum swing units control atmospheric concentrations of both CO2 and H2O through fully-regenerative process. The current concept, referred to as the rapid cycle amine (RCA), has resulted in numerous laboratory prototypes. Performance of these prototypes have been assessed experimentally and documented in previous reports. To support developmental e orts, a first principles model has also been established for the vacuum swing sorption technology. For the first time in several decades, a major re-design of Portable Life Support System (PLSS) for the extra-vehicular mobility unit (EMU) is underway. NASA at Johnson Space Center built and tested an integrated PLSS test bed of all subsystems under a variety of simulated EVA conditions of which the RCA prototype played a significant role. The efforts documented herein summarize RCA test performance and simulation results for single and variable metabolic rate experiments in an integrated context. In addition, a variety of off-nominal tests were performed to assess the capability of the RCA to function under challenging circumstances. Tests included high water production experiments, degraded vacuum regeneration, and deliberate valve/power failure and recovery.

Experimental and numerical investigation of the recovery ratio of a wedge-shaped hot-film probe

NASA Astrophysics Data System (ADS)

Krause, M.; Gaisbauer, U.; Kraemer, E.; Kosinov, A. D.

2017-03-01

The recovery ratio of a wedge-shaped hot-film probe was determined in an experimental as well as numerical study, since this information is still unpublished and essential for using the probe in hot-film anemometry. The experiments were conducted at the Khristianovich Institute of Theoretical and Applied Mechanics (ITAM) in Novosibirsk, Russia, and the simulations were performed with StarCCM+, a commercial 2nd order finite volume code. In the analysis, the Mach number was varied between M = 2 and M = 4, and the unit Reynolds number ranged from Re1 = 3.8•106 to Re1 = 26.1•106 m-1, depending on the Mach number. During the experiment, the stagnation temperature was kept constant for each Mach number at a separate value in the range of T 0 = 289 ± 7 K. Three different stagnation temperatures were used in the simulations: T 0 = 259 K, T 0 = 289 K, and T 0 = 319 K. The difference between the experimental and the numerical results is ≤ 0.5 %, and, therefore, both are in very good accordance. The influence of the Mach number, of the unit Reynolds number, and of the stagnation temperature was analysed, and three different fitting functions for the recovery ratio were established. In general, the recovery ratio shows small variations with all three tested parameters. These dependencies are of the same order of magnitude.

Sample size considerations for paired experimental design with incomplete observations of continuous outcomes.

PubMed

Zhu, Hong; Xu, Xiaohan; Ahn, Chul

2017-01-01

Paired experimental design is widely used in clinical and health behavioral studies, where each study unit contributes a pair of observations. Investigators often encounter incomplete observations of paired outcomes in the data collected. Some study units contribute complete pairs of observations, while the others contribute either pre- or post-intervention observations. Statistical inference for paired experimental design with incomplete observations of continuous outcomes has been extensively studied in literature. However, sample size method for such study design is sparsely available. We derive a closed-form sample size formula based on the generalized estimating equation approach by treating the incomplete observations as missing data in a linear model. The proposed method properly accounts for the impact of mixed structure of observed data: a combination of paired and unpaired outcomes. The sample size formula is flexible to accommodate different missing patterns, magnitude of missingness, and correlation parameter values. We demonstrate that under complete observations, the proposed generalized estimating equation sample size estimate is the same as that based on the paired t-test. In the presence of missing data, the proposed method would lead to a more accurate sample size estimate comparing with the crude adjustment. Simulation studies are conducted to evaluate the finite-sample performance of the generalized estimating equation sample size formula. A real application example is presented for illustration.

The effect of nurse manager turnover on patient fall and pressure ulcer rates.

PubMed

Warshawsky, Nora; Rayens, Mary Kay; Stefaniak, Karen; Rahman, Rana

2013-07-01

The purpose of this study was to explore the effects of nurse manager turnover on the occurrence of adverse events. Nurse managers create professional nurse practice environments to support the provision of quality patient outcomes. Inconsistent findings were reported in the literature testing the relationship between nurse managers and patient outcomes. All prior studies assumed stable nursing management. A longitudinal quasi-experimental study of 23 nursing units in two hospitals was used to determine whether unit characteristics, including nurse manager turnover, have an effect on patient falls or pressure ulcers. Statistical analyses included repeated measures and hierarchical modelling. Patients in medical/surgical units experienced more falls than in intensive care units (F1,11 = 15.9, P = 0.002). Patients in units with a nurse manager turnover [odds ratio: 3.16; 95% confidence interval: 1.49-6.70] and intensive care units (odds ratio: 2.70; 95% confidence interval: 1.33-5.49) were more likely to develop pressure ulcers. Nurse manager turnover and intensive care unit status were associated with more pressure ulcers. Medical/surgical unit status was associated with more falls. The study was limited by a small sample size. Nurse manager turnover may negatively impact patient outcomes. Stable nursing management, strategic interim management and long-term succession planning may reduce adverse patient events. © 2013 John Wiley & Sons Ltd.

Full-Scale Tests of a New Type NACA Nose-Slot Cowling

NASA Technical Reports Server (NTRS)

Theodorsen, Theodore; Brevoort, M J; Stickle, George W; Gough, M N

1937-01-01

An extended experimental study has been made in regard to the various refinements in the design of engine cowlings as related to the propeller-nacelle unit as a whole, under conditions corresponding to take-off, climb, and normal flight. The tests were all conducted at full scale in the 20-foot wind tunnel. This report presents the results of a novel type of engine cowling, characterized by the fact that the exit opening discharging the cooling air is not, as usual, located behind the engine but at the foremost extremity or nose of the cowling. The efficiency is found to be high, owing to the fact that higher velocities may be used in the exit opening.

Verification and Quantification of Single Event Effects on High Speed SRAM in Terrestrial Environments

NASA Technical Reports Server (NTRS)

Huff, H.; You, Z.; Williams, T.; Nichols, T.; Attia, J.; Fogarty, T. N.; Kirby, K.; Wilkins, R.; Lawton, R.

1998-01-01

As integrated circuits become more sensitive to charged particles and neutrons, anomalous performance due to single event effects (SEE) is a concern and requires experimental verification and quantification. The Center for Applied Radiation Research (CARR) at Prairie View A&M University has developed experiments as a participant in the NASA ER-2 Flight Program, the APEX balloon flight program and the Student Launch Program. Other high altitude and ground level experiments of interest to DoD and commercial applications are being developed. The experiment characterizes the SEE behavior of high speed and high density SRAM's. The system includes a PC-104 computer unit, an optical drive for storage, a test board with the components under test, and a latchup detection and reset unit. The test program will continuously monitor the stored checkerboard data pattern in the SW and record errors. Since both the computer and the optical drive contain integrated circuits, they are also vulnerable to radiation effects. A latchup detection unit with discrete components will monitor the test program and reset the system when necessary. The first results will be obtained from the NASA ER-2 flights, which are now planned to take place in early 1998 from Dryden Research Center in California. The series of flights, at altitudes up to 70,000 feet, and a variety of flight profiles should yield a distribution of conditions for correlating SEES. SEE measurements will be performed from the time of aircraft power-up on the ground throughout the flight regime until systems power-off after landing.

The ejector-loop fermenter: Description and performance of the apparatus.

PubMed

Moresi, M; Bartolo Gianturco, G; Sebastiani, E

1983-12-01

A novel fermentation unit, the ejector-loop fermenter (ELF), consisting of an outer-loop tower fermenter, a centrifugal pump, a plate-heat exchanger, and a gas-liquid ejector, was designed and constructed. Aeration was achieved by continuously recirculating the fermentation medium through two different nozzle devices instead of using the traditional expensive air compressor. By carrying out a whey fermentation with Kluyveromyces fragilis as the test organism, either in the ELF or in conventional stirred fermenter, it was possible to confirm that the high sheat streses and mixing shock occurring in the ejector nozzle and diffuser sections did not affect microbial growth. Within the range of experimental power consumption per unit volume (-0.1-5 kW/m(3)), the oxygen transfer capability of the ELF per unit power input was found to vary from 1 to 2.5 kg O(2) kW(-1)h(-1). Moreover, it is shown that there is suficient room for improvement in the performance of the ELF unit by care fully designing the aeration device. In fact, at constant volumetric oxygen transfer coefficient, the power consumpotion per unit volume in a 4-mm nozzle was found to be about 40% less than that in a 6-mm nozzle.

A centerless grinding unit used for precisely processing ferrules of optical fiber connector

NASA Astrophysics Data System (ADS)

Wu, Yongbo; Kondo, Takahiro; Kato, Masana

2005-02-01

This paper describes the development of a centerless grinding unit used for precisely processing ferrules, a key component of optical fiber connectors. In conventional processing procedure, the outer diameter of a ferrule is ground by employing a special machine tool, i.e., centerless grinder. However, in the case of processing small amount of ferrules, introducing a centerless grinder leads to high processing cost. Therefore, in order to take measures against this problem, the present authors propose a new centerless grinding technique where a compact centerless grinding unit, which is composed of an ultrasonic elliptic-vibration shoe, a workrest blade, and their respective holders, is installed on a popular surface grinder to perform the centerless grinding operations for outer diameter machining of ferrules. In this work, a unit is designed and constructed, and is installed on a surface grinder equipped with a diamond grinding wheel. Then, the performance of the unit is examined experimentally followed by grinding tests of ferrule"s outer diameter. As a result, the roundness of the ferrule"s outer diameter improved from the original value of around 3μm to the final value of around 0.5 μm, confirming the validity of the new technique.

Experimental Performance Evaluation of a High Speed Permanent Magnet Synchronous Motor and Drive for a Flywheel Application at Different Frequencies

NASA Technical Reports Server (NTRS)

Nagorny, Aleksandr S.; Jansen, Ralph H.; Kankam, M. David

2007-01-01

This paper presents the results of an experimental performance characterization study of a high speed, permanent magnet motor/generator (M/G) and drive applied to a flywheel module. Unlike the conventional electric machine the flywheel M/G is not a separated unit; its stator and rotor are integrated into a flywheel assembly. The M/G rotor is mounted on a flywheel rotor, which is magnetically levitated and sealed within a vacuum chamber during the operation. Thus, it is not possible to test the M/G using direct load measurements with a dynamometer and torque transducer. Accordingly, a new in-situ testing method had to be developed. The paper describes a new flywheel M/G and drive performance evaluation technique, which allows the estimation of the losses, efficiency and power quality of the flywheel high speed permanent magnet M/G, while working in vacuum, over wide frequency and torque ranges. This method does not require any hardware modification nor any special addition to the test rig. This new measurement technique is useful for high-speed applications, when applying an external load is technically difficult.

Meteorite Material Model for Structural Properties

NASA Technical Reports Server (NTRS)

Agrawal, Parul; Carlozzi, Alexander A.; Karajeh, Zaid S.; Bryson, Kathryn L.

2017-01-01

To assess the threat posed by an asteroid entering Earth's atmosphere, one must predict if, when, and how it fragments during entry. A comprehensive understanding of the asteroid material properties is needed to achieve this objective. At present, the meteorite material found on earth are the only objects from an entering asteroid that can be used as representative material and be tested inside a laboratory setting. Due to complex petrology, it is technically challenging and expensive to obtain reliable material properties by means of laboratory test for a family of meteorites. In order to circumvent this challenge, meteorite unit models are developed to determine the effective material properties including Youngs modulus, compressive and tensile strengths and Poissons ratio, that in turn would help deduce the properties of asteroids. The meteorite unit is a representative volume that accounts for diverse minerals, porosity, cracks and matrix composition. The Youngs Modulus and Poissons Ratio in the meteorite units are calculated by performing several hundreds of Monte-Carlo simulations by randomly distributing the various phases inside these units. Once these values are obtained, cracks are introduced in these meteorite units. The size, orientation and distribution of cracks are derived by extensive CT-scans and visual scans of various meteorites from the same family. Subsequently, simulations are performed to attain stress-strain relations, strength and effective modulus values in the presence of these cracks. The meteorite unit models are presented for H, L and LL ordinary chondrites, as well as for terrestrial basalt. In the case of the latter, data from the simulations is compared with experimental data to validate the methodology. These material models will be subsequently used in fragmentation modeling of full scale asteroids.

Short Duration Reduced Gravity Drop Tower Design and Development

NASA Astrophysics Data System (ADS)

Osborne, B.; Welch, C.

The industrial and commercial development of space-related activities is intimately linked to the ability to conduct reduced gravity research. Reduced gravity experimentation is important to many diverse fields of research in the understanding of fundamental and applied aspects of physical phenomena. Both terrestrial and extra-terrestrial experimental facilities are currently available to allow researchers access to reduced gravity environments. This paper discusses two drop tower designs, a 2.0 second facility built in Australia and a proposed 2.2 second facility in the United Kingdom. Both drop towers utilise a drag shield for isolating the falling experiment from the drag forces of the air during the test. The design and development of The University of Queensland's (Australia) 2.0 second drop tower, including its specifications and operational procedures is discussed first. Sensitive aspects of the design process are examined. Future plans are then presented for a new short duration (2.2 sec) ground-based reduced gravity drop tower. The new drop tower has been designed for Kingston University (United Kingdom) to support teaching and research in the field of reduced gravity physics. The design has been informed by the previous UQ drop tower design process and utilises a catapult mechanism to increase test time and also incorporates features to allow participants for a variety of backgrounds (from high school students through to university researchers) to learn and experiment in reduced gravity. Operational performance expectations for this new facility are also discussed.

Uptake rate constants and partition coefficients for vapor phase organic chemicals using semipermeable membrane devices (SPMDs)

USGS Publications Warehouse

Cranor, W.L.; Alvarez, D.A.; Huckins, J.N.; Petty, J.D.

2009-01-01

To fully utilize semipermeable membrane devices (SPMDs) as passive samplers in air monitoring, data are required to accurately estimate airborne concentrations of environmental contaminants. Limited uptake rate constants (kua) and no SPMD air partitioning coefficient (Ksa) existed for vapor-phase contaminants. This research was conducted to expand the existing body of kinetic data for SPMD air sampling by determining kua and Ksa for a number of airborne contaminants including the chemical classes: polycyclic aromatic hydrocarbons, organochlorine pesticides, brominated diphenyl ethers, phthalate esters, synthetic pyrethroids, and organophosphate/organosulfur pesticides. The kuas were obtained for 48 of 50 chemicals investigated and ranged from 0.03 to 3.07??m3??g-1??d-1. In cases where uptake was approaching equilibrium, Ksas were approximated. Ksa values (no units) were determined or estimated for 48 of the chemicals investigated and ranging from 3.84E+5 to 7.34E+7. This research utilized a test system (United States Patent 6,877,724 B1) which afforded the capability to generate and maintain constant concentrations of vapor-phase chemical mixtures. The test system and experimental design employed gave reproducible results during experimental runs spanning more than two years. This reproducibility was shown by obtaining mean kua values (n??=??3) of anthracene and p,p???-DDE at 0.96 and 1.57??m3??g-1??d-1 with relative standard deviations of 8.4% and 8.6% respectively.

Effects of the Integrated Online Advance Organizer Teaching Materials on Students' Science Achievement and Attitude

NASA Astrophysics Data System (ADS)

Korur, Fikret; Toker, Sacip; Eryılmaz, Ali

2016-08-01

This two-group quasi-experimental study investigated the effects of the Online Advance Organizer Concept Teaching Material (ONACOM) integrated with inquiry teaching and expository teaching methods. Grade 7 students' posttest performances on the light unit achievement and light unit attitude tests controlled for gender, previous semester science grade, and pretest scores were analyzed. No significant treatment effects were found between the inquiry and expository approaches. However, both groups demonstrated significant pretest-posttest gains in achievement and attitude. Independent from the method used, ONACOM was judged effective in both groups as students demonstrated increased achievement and attitude scores. ONACOM has a social and semantic network-aided infrastructure that can be adapted to both methods to increase students' achievement and improve their attitude.

Transforming prevention systems in the United States and the Netherlands using Communities That Care Promising prevention in the eyes of Josine Junger-Tas

PubMed Central

Steketee, Majone; Oesterle, Sabrina; Jonkman, Harrie; Hawkins, J. David; Haggerty, Kevin P.; Aussems, Claire

2013-01-01

Josine Junger-Tas introduced the Communities That Care (CTC) prevention system to the Netherlands as a promising approach to address the growing youth violence and delinquency. Using data from a randomized trial of CTC in the United States and a quasi-experimental study of CTC in the Netherlands, this article describes the results of a comparison of the implementation of CTC in 12 U.S. communities and 5 Dutch neighborhoods. CTC communities in both countries achieved higher stages of a science-based approach to prevention than control communities, but full implementation of CTC in the Netherlands was hampered by the very small list of prevention programs tested and found effective in the Dutch context. PMID:24465089

Research exemption/experimental use in the European Union: patents do not block the progress of science.

PubMed

Jaenichen, Hans-Rainer; Pitz, Johann

2014-11-06

In the public debate about patents, specifically in the area of biotechnology, the position has been taken that patents block the progress of science. As we demonstrate in this review, this is not the case in the European Union (EU). The national patent acts of the EU member states define research and experimental use exemptions from patent infringement that allow sufficient room for research activities to promote innovation. This review provides a comparative overview of the legal requirements and the extent and limitations of experimental use exemptions, including the so-called Bolar provision, in Germany, the United Kingdom, France, Spain, Italy, and The Netherlands. The legal framework in the respective countries is illustrated with reference to practical examples concerning tests on patent-protected genetic targets and antibodies. Specific questions concerning the use of patent-protected research tools, the outsourcing of research activities, and the use of preparatory and supplying acts for experimental purposes that are necessary for conducting experiments are covered. Copyright © 2015 Cold Spring Harbor Laboratory Press; all rights reserved.

Comparison of forcefields for molecular dynamics simulations of hydrocarbon phase diagrams

NASA Astrophysics Data System (ADS)

Pisarev, V. V.; Zakharov, S. A.

2018-01-01

Molecular dynamics calculations of vapor-liquid equilibrium of methane-n-butane mixture are performed. Three force-field models are tested: the TraPPE-UA united-atom forcefield, LOPLS-AA all-atom forcefield and a fully flexible version of the TraPPE-EH all-atom forcefield. All those forcefields reproduce well the composition of liquid phase in the mixture as a function of pressure at the 300 K isotherm, while significant discrepancies from experimental data are observed in the saturated vapor compositions with OPLS-AA and TraPPE-UA forcefields. The best agreement with the experimental phase diagram is found with TraPPE-EH forcefield which accurately reproduces compositions of both liquid and vapor phase. This forcefield can be recommended for simulation of two-phase hydrocarbon systems.

Large area sheet task: Advanced dendritic web growth development

NASA Technical Reports Server (NTRS)

Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Hopkins, R. H.; Meier, D.; Schruben, J.

1981-01-01

The growth of silicon dendritic web for photovoltaic applications was investigated. The application of a thermal model for calculating buckling stresses as a function of temperature profile in the web is discussed. Lid and shield concepts were evaluated to provide the data base for enhancing growth velocity. An experimental web growth machine which embodies in one unit the mechanical and electronic features developed in previous work was developed. In addition, evaluation of a melt level control system was begun, along with preliminary tests of an elongated crucible design. The economic analysis was also updated to incorporate some minor cost changes. The initial applications of the thermal model to a specific configuration gave results consistent with experimental observation in terms of the initiation of buckling vs. width for a given crystal thickness.

The effects of enteral feeding improvement massage on premature infants: A randomised controlled trial.

PubMed

Kim, Hee-Young; Bang, Kyung-Sook

2018-01-01

To prove the effects of an enteral feeding improvement massage for premature infants with regard to their feeding, growing and superior mesentery artery blood flow aspect by a randomised controlled trial. Premature infants have feeding-related problems related to eating and absorbing nutrition due to their immature gastrointestinal function. Studies regarding the effectiveness of premature infants' enteral feeding improvement by tactile stimulation massage are rare. The study group was composed of 55 patients. Of the 55 patients, 26 were randomised into an experimental group and 29 were randomised into a control group. They were all born <34 weeks of gestational age between 1 July 2011 and 30 March 2012. Premature infants in the experimental group received enteral feeding improvement massage twice a day for 14 days, and infants in the control group received a sham exercise. The collected data were analysed by spss 19.0, through t test, chi-square test (Fisher's exact) and ANCOVA. (i) The experimental group had reached the day of full enteral feeding significantly faster. (ii) The experimental group had a higher superior mesentery artery peak velocity (V max ) and lower RI (resistant index). (iii) The experimental group of the feeding-intolerant subgroup had a higher superior mesentery artery V max and V min . (iv) The experimental group had a heavier weight and larger head circumference after 14 days. This study demonstrates that enteral feeding improvement massage can be helpful for achieving earlier full enteral feeding, more increased superior mesentery artery, and faster growing. In particular, it can be a therapeutic, independent and evidence-based nursing intervention for feeding-intolerant premature infants. Neonatal nurses in neonatal intensive care unit can apply enteral feeding improvement massage massage for feeding-intolerant infants. © 2017 John Wiley & Sons Ltd.

The impact of football training on motor development in male children.

PubMed

Erceg, Marko; Zagorac, Nebojsa; Katić, Ratko

2008-03-01

The aim of the study was to determine the effect of football school program and physical education curriculum on changes in the motor abilities of 7- and 8-year-old boys. The study included a sample of 180 boys divided into group 1 (7-year-old boys), subdivided to experimental (n = 40) and control (n = 50) groups, and group 2 (8-year-old boys), subdivided to experimental (n = 40) and control (n = 50) groups. Experimental groups included children attending three training units of football training over a 9-month period, in addition to the conventional physical education curriculum. Control groups included children attending only conventional physical education curriculum. All study subjects underwent testing with a battery of 12 motor tests at the beginning and at the end of the study. Results obtained by discriminative canonic analysis showed no statistically significant between-group difference in motor abilities at the beginning of the study. However, significant differences in favor of experimental groups were recorded at the end of the study. Favorable changes in all motor variables were observed in both experimental and control groups of children from the initial through the final state. These changes were more pronounced in experimental groups. Analysis of variance for difference variables (final to initial measurement) indicated programmed education in the form of football training in addition to regular physical education curriculum to predominantly influence the development of aerobic endurance, agility, speed and flexibility in 7-year-old boys, and of explosive strength, aerobic endurance, flexibility and speed in 8-year-old boys. In the latter, football training led to the formation of a motor complex integrating explosiveness, speed, coordination, endurance and flexibility as a general motor factor determining future quality development in football.

Quasi-experimental nonequivalent (pretest and posttest) control-group study of the effects of microcomputer-based laboratory systems on academic achievement in high school chemistry students at two South Carolina high schools

NASA Astrophysics Data System (ADS)

Venables, Jeffrey M.

The literature on microcomputer-based laboratories (MBL) lacks quantitative studies that measure the effect of MBL on student achievement. The purpose of this study was to investigate the effect of MBL systems on the achievement of high school chemistry students. The first research question examined the effect of MBL systems on student achievement in high school chemistry laboratories. The second question analyzed the effect of MBL systems on the academic achievement of students of different genders, ethnicities, and socioeconomic backgrounds. This quasi-experimental quantitative research study evaluated the effects of MBL on student achievement in high school chemistry. The sample consisted of 124 college preparatory chemistry students at two high schools in a South Carolina school district. There were 42 participants in the experimental group and 82 participants in the control group. Both experimental and groups completed a pre- and post-test with MBL being the independent variable. The mean difference score for the experimental group was compared to that of the control group using an independent-measures t test and an analysis of variance. For the second research question, results were analyzed using a two-factor analysis of variance. Participant scores were broken down by gender, ethnicity, and socioeconomic status in order to identify potential differences. The results revealed no significant differences between the experimental and control groups, and no significant differences in effects of MBL on different segments of the population. Future studies should examine students using MBL for longer durations than one unit of study. As society continues to make technological advances, the effective assessment and implementation of technology resources for the classroom are becoming increasingly important.

Development of the anode bipolar plate/membrane assembly unit for air breathing PEMFC stack using silicone adhesive bonding

NASA Astrophysics Data System (ADS)

Kim, Minkook; Lee, Dai Gil

2016-05-01

Polymer electrolyte membrane fuel cells (PEMFC) exhibit a wide power range, low operating temperature, high energy density and long life time. These advantages favor PEMFC for applications such as vehicle power sources, portable power, and backup power applications. With the push towards the commercialization of PEMFC, especially for portable power applications, the overall balance of plants (BOPs) of the systems should be minimized. To reduce the mass and complexity of the systems, air-breathing PEMFC stack design with open cathode channel configuration is being developed. However, the open cathode channel configuration incurs hydrogen leakage problem. In this study, the bonding strength of a silicon adhesive between the Nafion membrane and the carbon fiber/epoxy composite bipolar plate was measured. Then, an anode bipolar plate/membrane assembly unit which was bonded with the silicone adhesive was developed to solve the hydrogen leakage problem. The reliability of the anode bipolar plate/membrane assembly unit was estimated under the internal pressure of hydrogen by the FE analysis. Additionally, the gas sealability of the developed air breathing PEMFC unit cell was experimentally measured. Finally, unit cell performance of the developed anode bipolar plate/membrane assembly unit was tested and verified under operating conditions without humidity and temperature control.

Experimental broadband absorption enhancement in silicon nanohole structures with optimized complex unit cells.

PubMed

Lin, Chenxi; Martínez, Luis Javier; Povinelli, Michelle L

2013-09-09

We design silicon membranes with nanohole structures with optimized complex unit cells that maximize broadband absorption. We fabricate the optimized design and measure the optical absorption. We demonstrate an experimental broadband absorption about 3.5 times higher than an equally-thick thin film.

Some experience with Barnwell-Sewall type correction to two-dimensional airfoil data

NASA Technical Reports Server (NTRS)

Jenkins, R. V.

1984-01-01

A series of airfoils were tested in the Langley 0.3-Meter Transonic Cryogenic Tunnel (TCT) at Reynolds numbers from 2 to 50 million. The 0.3-m TCT is equipped with Barnwell slots designed to minimize blockage due to the tunnel flow and ceiling. This design suggests that sidewall corrections for blockage is needed, and that a lifting airfoil produces a change in angle of attack. Sidewall correction methods were developed for subsonic and subsonic-transonic flow. Comparisons of theory with experimental data obtained in the 0.3-m TCT for two airfoils, the British NPL 9510 and the German R-4 are presented. The NPL 9510 was tested as part of the NASA/United Kingdom Joint Aeronautical Program and R-4 was tested as part f the DFVLR/NASA Advanced Airfoil Research Program. For the NPL 9510 airfoil, only those test points that one would anticipate being difficult to predict theoretically are presented.

Mechanical characterization and force-displacement hysteretic curves from in-plane cyclic tests on strong masonry infills.

PubMed

Morandi, Paolo; Hak, Sanja; Magenes, Guido

2018-02-01

This article contains information related to a recent study "Performance-based interpretation of in-plane cyclic tests on RC frames with strong masonry infills" (Morandi et al., 2017 [1]). Motivated by the necessity to improve the knowledge of the in-plane seismic response of rigid strong masonry infills, a wide experimental campaign based on in-plane cyclic tests on full-scale RC infilled frame specimens, supplemented with a complete characterization of the materials, has been conducted at the laboratory of the Department of Civil Engineering and Architecture of the University of Pavia. The masonry is constituted by vertically perforated 35 cm thick clay units with tongue and groove and dry head-joints and general-purpose mortar bed-joints. The paper reports the results of the mechanical characterization and of the force-displacement hysteretic curves from the in-plane cyclic tests.

Thermal tests of the SGT5-4000F gas-turbine plant of the PGU-420T power-generating unit at Combined Heat And Power Plant 16 of Mosenergo

NASA Astrophysics Data System (ADS)

Teplov, B. D.; Radin, Yu. A.; Filin, A. A.; Rudenko, D. V.

2016-08-01

In December 2014, the PGU-420T power-generating unit was put into operation at the Combined Heat and Power Plant 16, an affiliated company of PAO Mosenergo. In 2014-2015, thermal tests of the SGT5- 4000F gas-turbine plant (GTP) integrated into the power-generating unit were carried out. In the article, the test conditions are described and the test results are presented and analyzed. During the tests, 92 operating modes within a wide range of electrical loads and ambient air temperatures and operating conditions of the GTP when fired with fuel oil were investigated. In the tests, an authorized automated measuring system was applied. The experimental data were processed according to ISO 2314:2009 "Gas turbines—Acceptance tests" standard. The available capacity and the GTP efficiency vary from 266 MW and 38.8% to 302 MW and 39.8%, respectively, within the ambient air temperature range from +24 to-12°C, while the turbine inlet temperature decreases from 1200 to 1250°C. The switch to firing fuel oil results in a reduction in the turbine inlet temperature and the capacity of the GTP. With the full load and a reduction in the ambient temperature from +24 to-12°C, the compressor efficiency decreases from 89.6 to 86.4%. The turbine efficiency is approximately 89-91%. Within the investigated range of power output, the emissions of nitrogen oxides do not exceed 35 ppm for the gas-fired plant and 65 ppm for the fuel-oil-fired plant. Within the range of the GTP power output from 50 to 100% of the rated output, the combustion chamber operates without underburning and with hardly any CO being formed. At low loads close to the no-load operation mode, the CO emissions drastically increase.

End-to-End Demonstrator of the Safe Affordable Fission Engine (SAFE) 30: Power Conversion and Ion Engine Operation

NASA Technical Reports Server (NTRS)

Hrbud, Ivana; VanDyke, Melissa; Houts, Mike; Goodfellow, Keith; Schafer, Charles (Technical Monitor)

2001-01-01

The Safe Affordable Fission Engine (SAFE) test series addresses Phase 1 Space Fission Systems issues in particular non-nuclear testing and system integration issues leading to the testing and non-nuclear demonstration of a 400-kW fully integrated flight unit. The first part of the SAFE 30 test series demonstrated operation of the simulated nuclear core and heat pipe system. Experimental data acquired in a number of different test scenarios will validate existing computational models, demonstrated system flexibility (fast start-ups, multiple start-ups/shut downs), simulate predictable failure modes and operating environments. The objective of the second part is to demonstrate an integrated propulsion system consisting of a core, conversion system and a thruster where the system converts thermal heat into jet power. This end-to-end system demonstration sets a precedent for ground testing of nuclear electric propulsion systems. The paper describes the SAFE 30 end-to-end system demonstration and its subsystems.

Comet sample acquisition for ROSETTA lander mission

NASA Astrophysics Data System (ADS)

Marchesi, M.; Campaci, R.; Magnani, P.; Mugnuolo, R.; Nista, A.; Olivier, A.; Re, E.

2001-09-01

ROSETTA/Lander is being developed with a combined effort of European countries, coordinated by German institutes. The commitment for such a challenging probe will provide a unique opportunity for in-situ analysis of a comet nucleus. The payload for coring, sampling and investigations of comet materials is called SD2 (Sampling Drilling and Distribution). The paper presents the drill/sampler tool and the sample transfer trough modeling, design and testing phases. Expected drilling parameters are then compared with experimental data; limited torque consumption and axial thrust on the tool constraint the operation and determine the success of tests. Qualification campaign involved the structural part and related vibration test, the auger/bit parts and drilling test, and the coring mechanism with related sampling test. Mechanical check of specimen volume is also reported, with emphasis on the measurement procedure and on the mechanical unit. The drill tool and all parts of the transfer chain were tested in the hypothetical comet environment, charcterized by frozen material at extreme low temperature and high vacuum (-160°C, 10-3 Pa).

Enamel colour changes after debonding using various bonding systems.

PubMed

Zaher, Abbas R; Abdalla, Essam M; Abdel Motie, Maha A; Rehman, Noman Atiq; Kassem, Hassan; Athanasiou, Athanasios E

2012-06-01

To test the possible association between enamel colour alteration and resin tag depth. In vitro laboratory study. Department of Orthodontics, Alexandria University, Egypt. Fifty freshly extracted human premolar teeth were equally divided randomly into a control and four experimental groups. Teeth in group I received only enamel prophylaxis. Teeth in groups II and III were etched with 35% phosphoric acid for 15 and 60 seconds, respectively. Teeth in group IV were conditioned with Prompt L-pop self-etching primer and in group V with Xeno III self-etching primer, according to the manufacturer's instructions. Orthodontic brackets were bonded to the teeth in all experimental groups using Transbond XT composite. Following bracket debonding, finishing and polishing were performed. Enamel colour was evaluated spectrophotometrically at baseline and then after debonding, with the corresponding colour differences ΔE calculated. Resin tags lengths were measured on sectioned teeth in each experimental group under scanning electron microscope. All experimental groups showed clinically perceivable colour change after debonding and finishing as all values were exceeded the clinical colour detection threshold of ΔE = 3.7 units. Significant differences (P<0.05) in resin tag length were found in all experimental groups. Significant moderate correlation was found between colour change and resin tags length when all teeth were combined and tested, irrespective of group. Moderate evidence exists that shorter resin tag penetration produces less change in enamel colour following clean-up and polishing. Self-etch primers produce less resin penetration and these systems may produce less iatrogenic colour change in enamel following orthodontic treatment.

Testing the responses of four wheat crop models to heat stress at anthesis and grain filling.

PubMed

Liu, Bing; Asseng, Senthold; Liu, Leilei; Tang, Liang; Cao, Weixing; Zhu, Yan

2016-05-01

Higher temperatures caused by future climate change will bring more frequent heat stress events and pose an increasing risk to global wheat production. Crop models have been widely used to simulate future crop productivity but are rarely tested with observed heat stress experimental datasets. Four wheat models (DSSAT-CERES-Wheat, DSSAT-Nwheat, APSIM-Wheat, and WheatGrow) were evaluated with 4 years of environment-controlled phytotron experimental datasets with two wheat cultivars under heat stress at anthesis and grain filling stages. Heat stress at anthesis reduced observed grain numbers per unit area and individual grain size, while heat stress during grain filling mainly decreased the size of the individual grains. The observed impact of heat stress on grain filling duration, total aboveground biomass, grain yield, and grain protein concentration (GPC) varied depending on cultivar and accumulated heat stress. For every unit increase of heat degree days (HDD, degree days over 30 °C), grain filling duration was reduced by 0.30-0.60%, total aboveground biomass was reduced by 0.37-0.43%, and grain yield was reduced by 1.0-1.6%, but GPC was increased by 0.50% for cv Yangmai16 and 0.80% for cv Xumai30. The tested crop simulation models could reproduce some of the observed reductions in grain filling duration, final total aboveground biomass, and grain yield, as well as the observed increase in GPC due to heat stress. Most of the crop models tended to reproduce heat stress impacts better during grain filling than at anthesis. Some of the tested models require improvements in the response to heat stress during grain filling, but all models need improvements in simulating heat stress effects on grain set during anthesis. The observed significant genetic variability in the response of wheat to heat stress needs to be considered through cultivar parameters in future simulation studies. © 2016 John Wiley & Sons Ltd.

X-33 Experimental Aeroheating at Mach 6 Using Phosphor Thermography

NASA Technical Reports Server (NTRS)

Horvath, Thomas J.; Berry, Scott A.; Hollis, Brian R.; Liechty, Derek S.; Hamilton, H. Harris, II; Merski, N. Ronald

1999-01-01

The goal of the NASA Reusable Launch Vehicle (RLV) technology program is to mature and demonstrate essential, cost effective technologies for next generation launch systems. The X-33 flight vehicle presently being developed by Lockheed Martin is an experimental Single Stage to Orbit (SSTO) demonstrator that seeks to validate critical technologies and insure applicability to a full scale RLV. As with the design of any hypersonic vehicle, the aeroheating environment is an important issue and one of the key technologies being demonstrated on X-33 is an advanced metallic Thermal Protection System (TPS). As part of the development of this TPS system, the X-33 aeroheating environment is being defined through conceptual analysis, ground based testing, and computational fluid dynamics. This report provides an overview of the hypersonic aeroheating wind tunnel program conducted at the NASA Langley Research Center in support of the ground based testing activities. Global surface heat transfer images, surface streamline patterns, and shock shapes were measured on 0.013 scale (10-in.) ceramic models of the proposed X-33 configuration in Mach 6 air. The test parametrics include angles of attack from -5 to 40 degs, unit Reynolds numbers from 1x106 to 8x106/ft, and body flap deflections of 0, 10, and 20 deg. Experimental and computational results indicate the presence of shock/shock interactions that produced localized heating on the deflected flaps and boundary layer transition on the canted fins. Comparisons of the experimental data to laminar and turbulent predictions were performed. Laminar windward heating data from the wind tunnel was extrapolated to flight surface temperatures and generally compared to within 50 deg F of flight prediction along the centerline. When coupled with the phosphor technique, this rapid extrapolation method would serve as an invaluable TPS design tool.

Solid oxide fuel cell short stack performance testing - Part A: Experimental analysis and μ-combined heat and power unit comparison

NASA Astrophysics Data System (ADS)

Mastropasqua, L.; Campanari, S.; Brouwer, J.

2017-12-01

The need to experimentally understand the detailed performance of SOFC stacks under operating conditions typical of commercial SOFC systems has prompted this two-part study. The steady state performance of a 6-cell short stack of yttria (Y2O3) stabilised zirconia (YSZ) with Ni/YSZ anodes and composite Sr-doped lanthanum manganite (LaMnO3, LSM)/YSZ cathodes is experimentally evaluated. In Part A, the stack characterisation is carried out by means of sensitivity analyses on the fuel utilisation factor and the steam-to-carbon ratio. Electrical and environmental performances are assessed and the results are compared with a commercial full-scale micro-CHP system, which comprises the same cells. The results show that the measured temperature dynamics of the short stack in a test stand environment are on the order of many minutes; therefore, one cannot neglect temperature dynamics for a precise measurement of the steady state polarisation behaviour. The overall polarisation performance is comparable to that of the full stack employed in the micro-CHP system, confirming the good representation that short-stack analyses can give of the entire SOFC module. The environmental performance is measured verifying the negligible values of NO emissions (<10 ppb) across the whole polarisation curve.

A novel analysis method for paired-sample microbial ecology experiments

DOE PAGES

Olesen, Scott W.; Vora, Suhani; Techtmann, Stephen M.; ...

2016-05-06

Many microbial ecology experiments use sequencing data to measure a community s response to an experimental treatment. In a common experimental design, two units, one control and one experimental, are sampled before and after the treatment is applied to the experimental unit. The four resulting samples contain information about the dynamics of organisms that respond to the treatment, but there are no analytical methods designed to extract exactly this type of information from this configuration of samples. Here we present an analytical method specifically designed to visualize and generate hypotheses about microbial community dynamics in experiments that have paired samplesmore » and few or no replicates. The method is based on the Poisson lognormal distribution, long studied in macroecology, which we found accurately models the abundance distribution of taxa counts from 16S rRNA surveys. To demonstrate the method s validity and potential, we analyzed an experiment that measured the effect of crude oil on ocean microbial communities in microcosm. Our method identified known oil degraders as well as two clades, Maricurvus and Rhodobacteraceae, that responded to amendment with oil but do not include known oil degraders. Furthermore, our approach is sensitive to organisms that increased in abundance only in the experimental unit but less sensitive to organisms that increased in both control and experimental units, thus mitigating the role of bottle effects .« less

A novel analysis method for paired-sample microbial ecology experiments

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

Olesen, Scott W.; Vora, Suhani; Techtmann, Stephen M.

Many microbial ecology experiments use sequencing data to measure a community s response to an experimental treatment. In a common experimental design, two units, one control and one experimental, are sampled before and after the treatment is applied to the experimental unit. The four resulting samples contain information about the dynamics of organisms that respond to the treatment, but there are no analytical methods designed to extract exactly this type of information from this configuration of samples. Here we present an analytical method specifically designed to visualize and generate hypotheses about microbial community dynamics in experiments that have paired samplesmore » and few or no replicates. The method is based on the Poisson lognormal distribution, long studied in macroecology, which we found accurately models the abundance distribution of taxa counts from 16S rRNA surveys. To demonstrate the method s validity and potential, we analyzed an experiment that measured the effect of crude oil on ocean microbial communities in microcosm. Our method identified known oil degraders as well as two clades, Maricurvus and Rhodobacteraceae, that responded to amendment with oil but do not include known oil degraders. Furthermore, our approach is sensitive to organisms that increased in abundance only in the experimental unit but less sensitive to organisms that increased in both control and experimental units, thus mitigating the role of bottle effects .« less

Quality by design: scale-up of freeze-drying cycles in pharmaceutical industry.

PubMed

Pisano, Roberto; Fissore, Davide; Barresi, Antonello A; Rastelli, Massimo

2013-09-01

This paper shows the application of mathematical modeling to scale-up a cycle developed with lab-scale equipment on two different production units. The above method is based on a simplified model of the process parameterized with experimentally determined heat and mass transfer coefficients. In this study, the overall heat transfer coefficient between product and shelf was determined by using the gravimetric procedure, while the dried product resistance to vapor flow was determined through the pressure rise test technique. Once model parameters were determined, the freeze-drying cycle of a parenteral product was developed via dynamic design space for a lab-scale unit. Then, mathematical modeling was used to scale-up the above cycle in the production equipment. In this way, appropriate values were determined for processing conditions, which allow the replication, in the industrial unit, of the product dynamics observed in the small scale freeze-dryer. This study also showed how inter-vial variability, as well as model parameter uncertainty, can be taken into account during scale-up calculations.

Research on a power management system for thermoelectric generators to drive wireless sensors on a spindle unit.

PubMed

Li, Sheng; Yao, Xinhua; Fu, Jianzhong

2014-07-16

Thermoelectric energy harvesting is emerging as a promising alternative energy source to drive wireless sensors in mechanical systems. Typically, the waste heat from spindle units in machine tools creates potential for thermoelectric generation. However, the problem of low and fluctuant ambient temperature differences in spindle units limits the application of thermoelectric generation to drive a wireless sensor. This study is devoted to presenting a transformer-based power management system and its associated control strategy to make the wireless sensor work stably at different speeds of the spindle. The charging/discharging time of capacitors is optimized through this energy-harvesting strategy. A rotating spindle platform is set up to test the performance of the power management system at different speeds. The experimental results show that a longer sampling cycle time will increase the stability of the wireless sensor. The experiments also prove that utilizing the optimal time can make the power management system work more effectively compared with other systems using the same sample cycle.

Research on a Power Management System for Thermoelectric Generators to Drive Wireless Sensors on a Spindle Unit

PubMed Central

Li, Sheng; Yao, Xinhua; Fu, Jianzhong

2014-01-01

Thermoelectric energy harvesting is emerging as a promising alternative energy source to drive wireless sensors in mechanical systems. Typically, the waste heat from spindle units in machine tools creates potential for thermoelectric generation. However, the problem of low and fluctuant ambient temperature differences in spindle units limits the application of thermoelectric generation to drive a wireless sensor. This study is devoted to presenting a transformer-based power management system and its associated control strategy to make the wireless sensor work stably at different speeds of the spindle. The charging/discharging time of capacitors is optimized through this energy-harvesting strategy. A rotating spindle platform is set up to test the performance of the power management system at different speeds. The experimental results show that a longer sampling cycle time will increase the stability of the wireless sensor. The experiments also prove that utilizing the optimal time can make the power management system work more effectively compared with other systems using the same sample cycle. PMID:25033189

The effect of the local use of chlorhexidine in surgical treatment of experimental peri-implantitis in dogs.

PubMed

Carcuac, Olivier; Abrahamsson, Ingemar; Charalampakis, Georgios; Berglundh, Tord

2015-02-01

To evaluate the effect of surgical treatment of experimental peri-implantitis at implants with different surface characteristics using different anti-infective procedures. Four implants with different surface characteristics (A: TiOblast, B: OsseoSpeed, C: AT-I, D: TiUnite) were installed in a randomized order in each side of the mandible in 6 labrador dogs 3 months after tooth extraction. Experimental peri-implantitis was induced 3 months later. Surgical treatment of peri-implantitis was performed. The implants were cleaned with gauze soaked in either saline (control) or chlorhexidine (test). Clinical and radiographical examinations were performed and microbiological samples were taken during a 6-month period after surgery. Biopsies were obtained and prepared for histological analysis. Clinical signs of soft tissue inflammation were reduced after surgical therapy in most test and control sites. While the analysis of bone level alterations in radiographs together with histological and microbiological assessments of resolution of peri-implantitis lesions failed to demonstrate statistically significant differences between test and control procedures, the evaluations disclosed significant differences between implant D and implants A, B and C on treatment outcome. It is suggested that (i) the local use of chlorhexidine has minor influence on treatment outcome, (ii) resolution of peri-implantitis following surgical treatment without the adjunctive use of local and systemic antimicrobial agents is possible and (iii) the results are influenced by implant surface characteristics. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Functional assessment of the ex vivo vocal folds through biomechanical testing: A review

PubMed Central

Dion, Gregory R.; Jeswani, Seema; Roof, Scott; Fritz, Mark; Coelho, Paulo; Sobieraj, Michael; Amin, Milan R.; Branski, Ryan C.

2016-01-01

The human vocal folds are complex structures made up of distinct layers that vary in cellular and extracellular composition. The mechanical properties of vocal fold tissue are fundamental to the study of both the acoustics and biomechanics of voice production. To date, quantitative methods have been applied to characterize the vocal fold tissue in both normal and pathologic conditions. This review describes, summarizes, and discusses the most commonly employed methods for vocal fold biomechanical testing. Force-elongation, torsional parallel plate rheometry, simple-shear parallel plate rheometry, linear skin rheometry, and indentation are the most frequently employed biomechanical tests for vocal fold tissues and each provide material properties data that can be used to compare native tissue verses diseased for treated tissue. Force-elongation testing is clinically useful, as it allows for functional unit testing, while rheometry provides physiologically relevant shear data, and nanoindentation permits micrometer scale testing across different areas of the vocal fold as well as whole organ testing. Thoughtful selection of the testing technique during experimental design to evaluate a hypothesis is important to optimizing biomechanical testing of vocal fold tissues. PMID:27127075

A portable device for rapid nondestructive detection of fresh meat quality

NASA Astrophysics Data System (ADS)

Lin, Wan; Peng, Yankun

2014-05-01

Quality attributes of fresh meat influence nutritional value and consumers' purchasing power. In order to meet the demand of inspection department for portable device, a rapid and nondestructive detection device for fresh meat quality based on ARM (Advanced RISC Machines) processor and VIS/NIR technology was designed. Working principal, hardware composition, software system and functional test were introduced. Hardware system consisted of ARM processing unit, light source unit, detection probe unit, spectral data acquisition unit, LCD (Liquid Crystal Display) touch screen display unit, power unit and the cooling unit. Linux operating system and quality parameters acquisition processing application were designed. This system has realized collecting spectral signal, storing, displaying and processing as integration with the weight of 3.5 kg. 40 pieces of beef were used in experiment to validate the stability and reliability. The results indicated that prediction model developed using PLSR method using SNV as pre-processing method had good performance, with the correlation coefficient of 0.90 and root mean square error of 1.56 for validation set for L*, 0.95 and 1.74 for a*，0.94 and 0.59 for b*, 0.88 and 0.13 for pH, 0.79 and 12.46 for tenderness, 0.89 and 0.91 for water content, respectively. The experimental result shows that this device can be a useful tool for detecting quality of meat.

Experimental Investigation of SBLI to Unravel Inlet Unstart Physics

NASA Astrophysics Data System (ADS)

Funderburk, Morgan; Narayanaswamy, Venkateswaran

2016-11-01

The phenomenon of shock boundary layer interaction (SBLI) driven inlet unstart persists as one of the most significant problems facing supersonic ramjet/scramjet engines. In order to determine how the characteristics of the SBLI units specific to rectangular inlets evolve during an unstart event, an experimental investigation is made using surface streakline methods and pitot/wall pressure measurements in the vicinity of the floor and corner SBLI induced by a compression ramp in a rectangular channel. Mean and unsteady measurements were taken at a variety of shock strengths to simulate the evolution of the combustion-induced back pressure ratio during unstart. The freestream Mach number was also varied. Statistical correlation methods were used to determine the degree of interaction between the floor and corner SBLI with different flowfield locations for the various test conditions. Finally, comparison to a two-dimensional compression ramp SBLI was made to determine any modification caused by the introduction of the corner SBLI. Results indicate that the floor and corner SBLI transition from distinct units to members of a global separated flow with increasing back pressure, and that considerable modification of the floor SBLI by the corner flow occurs. AFOSR Grant FA9550-15-1-0296.

Structural Optimization of Triboelectric Nanogenerator for Harvesting Water Wave Energy.

PubMed

Jiang, Tao; Zhang, Li Min; Chen, Xiangyu; Han, Chang Bao; Tang, Wei; Zhang, Chi; Xu, Liang; Wang, Zhong Lin

2015-12-22

Ocean waves are one of the most abundant energy sources on earth, but harvesting such energy is rather challenging due to various limitations of current technologies. Recently, networks formed by triboelectric nanogenerator (TENG) have been proposed as a promising technology for harvesting water wave energy. In this work, a basic unit for the TENG network was studied and optimized, which has a box structure composed of walls made of TENG composed of a wavy-structured Cu-Kapton-Cu film and two FEP thin films, with a metal ball enclosed inside. By combination of the theoretical calculations and experimental studies, the output performances of the TENG unit were investigated for various structural parameters, such as the size, mass, or number of the metal balls. From the viewpoint of theory, the output characteristics of TENG during its collision with the ball were numerically calculated by the finite element method and interpolation method, and there exists an optimum ball size or mass to reach maximized output power and electric energy. Moreover, the theoretical results were well verified by the experimental tests. The present work could provide guidance for structural optimization of wavy-structured TENGs for effectively harvesting water wave energy toward the dream of large-scale blue energy.

Modelling short time series in metabolomics: a functional data analysis approach.

PubMed

Montana, Giovanni; Berk, Maurice; Ebbels, Tim

2011-01-01

Metabolomics is the study of the complement of small molecule metabolites in cells, biofluids and tissues. Many metabolomic experiments are designed to compare changes observed over time under two or more experimental conditions (e.g. a control and drug-treated group), thus producing time course data. Models from traditional time series analysis are often unsuitable because, by design, only very few time points are available and there are a high number of missing values. We propose a functional data analysis approach for modelling short time series arising in metabolomic studies which overcomes these obstacles. Our model assumes that each observed time series is a smooth random curve, and we propose a statistical approach for inferring this curve from repeated measurements taken on the experimental units. A test statistic for detecting differences between temporal profiles associated with two experimental conditions is then presented. The methodology has been applied to NMR spectroscopy data collected in a pre-clinical toxicology study.

Improved thermodynamic modeling of the no-vent fill process and correlation with experimental data

NASA Technical Reports Server (NTRS)

Taylor, William J.; Chato, David J.

1991-01-01

The United States' plans to establish a permanent manned presence in space and to explore the Solar System created the need to efficiently handle large quantities of subcritical cryogenic fluids, particularly propellants such as liquid hydrogen and liquid oxygen, in low- to zero-gravity environments. One of the key technologies to be developed for fluid handling is the ability to transfer the cryogens between storage and spacecraft tanks. The no-vent fill method was identified as one way to perform this transfer. In order to understand how to apply this method, a model of the no-vent fill process is being developed and correlated with experimental data. The verified models then can be used to design and analyze configurations for tankage and subcritical fluid depots. The development of an improved macroscopic thermodynamic model is discussed of the no-vent fill process and the analytical results from the computer program implementation of the model are correlated with experimental results for two different test tanks.

Comparison of theoretical and experimental boundary-layer development in a Mach 2.5 mixed-compression inlet

NASA Technical Reports Server (NTRS)

Hingst, W. R.; Towne, C. E.

1974-01-01

An analytical investigation was made of the boundary layer flow in an axisymmetric Mach 2.5 mixed compression inlet, and the results were compared with experimental measurements. The inlet tests were conducted in the Lewis 10- by 10-foot supersonic wind tunnel at a unit Reynolds number of 8.2 million/m. The inlet incorporated porous bleed regions for boundary layer control, and the effect of this bleed was taken into account in the analysis. The experimental boundary layer data were analyzed by using similarity laws from which the skin friction coefficient was obtained. The boundary layer analysis included predictions of laminar and turbulent boundary layer growth, transition, and the effects of the shock boundary layer interactions. In addition, the surface static pressures were compared with those obtained from an inviscid characteristics program. The results of investigation showed that the analytical techniques gave satisfactory predictions of the boundary layer flow except in regions that were badly distorted by the terminal shock.

Review of Combustion Stability Characteristics of Swirl Coaxial Element Injectors

NASA Technical Reports Server (NTRS)

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

2013-01-01

Liquid propellant rocket engine injectors using coaxial elements where the center liquid is swirled have become more common in the United States over the past several decades, although primarily for technology or advanced development programs. Currently, only one flight engine operates with this element type in the United States (the RL10 engine), while the element type is very common in Russian (and ex-Soviet) liquid propellant rocket engines. In the United States, the understanding of combustion stability characteristics of swirl coaxial element injectors is still very limited, despite the influx of experimental and theoretical information from Russia. The empirical and theoretical understanding is much less advanced than for the other prevalent liquid propellant rocket injector element types, the shear coaxial and like-on-like paired doublet. This paper compiles, compares and explores the combustion stability characteristics of swirl coaxial element injectors tested in the United States, dating back to J-2 and RL-10 development, and extending to very recent programs at the NASA MSFC using liquid oxygen and liquid methane and kerosene propellants. Included in this study are several other relatively recent design and test programs, including the Space Transportation Main Engine (STME), COBRA, J-2X, and the Common Extensible Cryogenic Engine (CECE). A presentation of the basic data characteristics is included, followed by an evaluation by several analysis techniques, including those included in Rocket Combustor Interactive Design and Analysis Computer Program (ROCCID), and methodologies described by Hewitt and Bazarov.

The impact of constructivist teaching strategies on the acquisition of higher order cognition and learning

NASA Astrophysics Data System (ADS)

Merrill, Alison Saricks

The purpose of this quasi-experimental quantitative mixed design study was to compare the effectiveness of brain-based teaching strategies versus a traditional lecture format in the acquisition of higher order cognition as determined by test scores. A second purpose was to elicit student feedback about the two teaching approaches. The design was a 2 x 2 x 2 factorial design study with repeated measures on the last factor. The independent variables were type of student, teaching method, and a within group change over time. Dependent variables were a between group comparison of pre-test, post-test gain scores and a within and between group comparison of course examination scores. A convenience sample of students enrolled in medical-surgical nursing was used. One group (n=36) was made up of traditional students and the other group (n=36) consisted of second-degree students. Four learning units were included in this study. Pre- and post-tests were given on the first two units. Course examinations scores from all four units were compared. In one cohort two of the units were taught via lecture format and two using constructivist activities. These methods were reversed for the other cohort. The conceptual basis for this study derives from neuroscience and cognitive psychology. Learning is defined as the growth of new dendrites. Cognitive psychologists view learning as a constructive activity in which new knowledge is built on an internal foundation of existing knowledge. Constructivist teaching strategies are designed to stimulate the brain's natural learning ability. There was a statistically significant difference based on type of teaching strategy (t = -2.078, df = 270, p = .039, d = .25)) with higher mean scores on the examinations covering brain-based learning units. There was no statistical significance based on type of student. Qualitative data collection was conducted in an on-line forum at the end of the semester. Students had overall positive responses about the constructivist activities. Major themes were described. Constructivist strategies help bridge the gap between neurological and cognitive sciences and classroom teaching and learning. A variety of implications for nursing educators are outlined as well as directions for future research.

The LENS Facilities and Experimental Studies to Evaluate the Modeling of Boundary Layer Transition, Shock/Boundary Layer Interaction, Real Gas, Radiation and Plasma Phenomena in Contemporary CFD Codes

DTIC Science & Technology

2010-04-01

Layer Interaction, Real Gas, Radiation and Plasma Phenomena in Contemporary CFD Codes Michael S. Holden, PhD CUBRC , Inc. 4455 Genesee Street Buffalo...NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) CUBRC , Inc. 4455 Genesee Street Buffalo, NY 14225, USA 8. PERFORMING...HyFly Navy EMRG Reentry-F Slide 2 X-43 HIFiRE-2 Figure 17: Transition in Hypervelocity Flows: CUBRC Focus – Fully Duplicated Ground Test

Gasification of land-based biomass. Final report July 78-December 82

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

Chynoweth, D.P.; Jerger, D.E.; Conrad, J.R.

1983-06-01

The objective of this research was to develop efficient processes for conversion of land-based biomass to methane and other resources. One task was to determine the relative suitability of selected species or feedstocks for biological and thermal gasification processes. The second task was to narrow options for design and operation of the experimental test unit (ETU) on water hyacinth and sludge at Walt Disney World (WDW) and to provide a scientific base for understanding rate- and yield-limiting reactions for biogasification of these feedstocks, (separately and as blends).

Space Shuttle STS-87 Columbia launch

NASA Technical Reports Server (NTRS)

1997-01-01

Like a rising sun lighting up the afternoon sky, the Space Shuttle Columbia (STS-87) soared from Launch Pad 39B on the fourth flight of the United States Microgravity Payload (USMP-4) and Spartan-201 satellite which were managed by scientists and engineers from the Marshall Space Flight Center. During the 16-day mission, the crew oversaw experiments in microgravity; deployed and retrieved a solar satellite; and tested a new experimental camera, the AERCam Sprint. Two crew members, Dr. Takao Doi and Winston Scott also performed a spacewalk to practice International Space Station maneuvers.

Superconducting fault current limiter for railway transport

NASA Astrophysics Data System (ADS)

Fisher, L. M.; Alferov, D. F.; Akhmetgareev, M. R.; Budovskii, A. I.; Evsin, D. V.; Voloshin, I. F.; Kalinov, A. V.

2015-12-01

A resistive switching superconducting fault current limiter (SFCL) for DC networks with voltage of 3.5 kV and nominal current of 2 kA is developed. The SFCL consists of two series-connected units: block of superconducting modules and high-speed vacuum breaker with total disconnection time not more than 8 ms. The results of laboratory tests of superconducting SFCL modules in current limiting mode are presented. The recovery time of superconductivity is experimentally determined. The possibility of application of SFCL on traction substations of Russian Railways is considered.

Effects of a home-exercise therapy programme on cervical and lumbar range of motion among nurses with neck and lower back pain: a quasi-experimental study.

PubMed

Freimann, Tiina; Merisalu, Eda; Pääsuke, Mati

2015-01-01

Cervical and lumbar range of motion limitations are usually associated with musculoskeletal pain in the neck and lower back, and are a major health problem among nurses. Physical exercise has been evaluated as an effective intervention method for improving cervical and lumbar range of motion, and for preventing and reducing musculoskeletal pain. The purpose of this study was to investigate the effects of a home-exercise therapy programme on cervical and lumbar range of motion among intensive care unit nurses who had experienced mild to moderate musculoskeletal pain in the neck and or lower back during the previous six months. A quasi-experimental study was conducted among intensive care unit nurses at Tartu University Hospital (Estonia) between May and July 2011. Thirteen nurses who had suffered musculoskeletal pain episodes in the neck and or lower back during the previous six months underwent an 8-week home-exercise therapy programme. Eleven nurses without musculoskeletal pain formed a control group. Questions from the Nordic Musculoskeletal Questionnaire and the 11-point Visual Analogue Scale were used to select potential participants for the experimental group via an assessment of the prevalence and intensity of musculoskeletal pain. Cervical range of motion and lumbar range of motion in flexion, extension, lateral flexion and (cervical range of motion only) rotation were measured with a digital goniometer. A paired t-test was used to compare the measured parameters before and after the home-exercise therapy programme. A Student's t-test was used to analyse any differences between the experimental and control groups. After the home-exercise therapy, there was a significant increase (p < 0.05) in cervical range of motion in flexion, extension, lateral flexion and rotation, and in lumbar range of motion in lateral flexion. Cervical range of motion in flexion was significantly higher (p < 0.01) in the experimental group compared to the control group after therapy. Our results suggest an 8-week intensive home-exercise therapy programme may improve cervical and lumbar range of motion among intensive care nurses. Further studies are needed to develop this simple but effective home-exercise therapy programme to help motivate nurses to perform such exercises regularly. Current Controlled Trials ISRCTN19278735. Registered 27 November 2015.

HandTutor™ enhanced hand rehabilitation after stroke--a pilot study.

PubMed

Carmeli, Eli; Peleg, Sara; Bartur, Gadi; Elbo, Enbal; Vatine, Jean-Jacques

2011-12-01

This study assessed the potential therapeutic benefi t of using HandTutor™ in combination with traditional rehabilitation in a post-stroke sub-acute population. The study compares an experimental group receiving traditional therapy combined with HandTutorTM treatment, against a control group receiving only traditional therapy. An assessor-blinded, randomized controlled pilot trial, was conducted in the Reuth rehabilitation unit in Israel. Thirty-one stroke patients in the sub-acute phase, were randomly assigned to one of the two groups (experimental or control) in sets of three. The experimental group (n = 16) underwent a hand rehabilitation programme using the HandTutorTM combined with traditional therapy. The control group (n = 15) received only traditional therapy. The treatment schedules for both groups were of similar duration and frequency. Improvements were evaluated using three indicators: 1) The Brunnström-Fugl-Meyer (FM) test, 2) the Box and Blocks (B&B) test and 3) improvement parameters as determined by the HandTutorTM software. Following 15 consecutive treatment sessions, a signifi cant improvement was observed within the experimental group (95% confi dence intervals) compared with the control group: B&B p = 0.015; FM p = 0.041, HandTutor™ performance accuracy on x axis and performance accuracy on y axis p < 0.0003. The results from this pilot study support further investigation of the use of the HandTutorTM in combination with traditional occupational therapy and physiotherapy during post stroke hand function rehabilitation.

Psychoeducational preparation of children for surgery: the importance of parental involvement.

PubMed

Li, Ho Cheung William; Lopez, Violeta; Lee, Tin Loi Isabel

2007-01-01

To examine the effects of therapeutic play intervention on outcomes of children undergoing day surgery, and to highlight the importance of parental involvement in the psychoeducational preparation of children for surgery. A randomized controlled trial, two group pre-test and repeated post-test, between subjects design was employed. Hong Kong Chinese children (7-12 years of age; n=203) admitted for elective surgery in a day surgery unit, along with their parents during a 13-month period, were invited to participate in the study. By using a simple complete randomization method, 97 of children with their parents were assigned to the experimental group receiving therapeutic play intervention, and 106 children with their parents were assigned to the control group receiving routine information preparation. The results showed that both children and their parents in the experimental group reported lower state anxiety scores in pre- and post-operative periods. Children in the experimental group exhibited fewer instances of negative emotional behaviors and parents in the experimental group reported greater satisfaction. The results, however, find no differences in children's post-operative pain between the two groups. The study provides empirical evidence to support the effectiveness of using therapeutic play intervention and the importance of parental involvement in the psychoeducational preparation of children for surgery. The findings heighten the awareness of the importance of integrating therapeutic play and parental involvement as essential components of holistic and quality nursing care to prepare children for surgery.

Comparing the Hydrologic and Watershed Processes between a Full Scale Stochastic Model Versus a Scaled Physical Model of Bell Canyon

NASA Astrophysics Data System (ADS)

Hernandez, K. F.; Shah-Fairbank, S.

2016-12-01

The San Dimas Experimental Forest has been designated as a research area by the United States Forest Service for use as a hydrologic testing facility since 1933 to investigate watershed hydrology of the 27 square mile land. Incorporation of a computer model provides validity to the testing of the physical model. This study focuses on San Dimas Experimental Forest's Bell Canyon, one of the triad of watersheds contained within the Big Dalton watershed of the San Dimas Experimental Forest. A scaled physical model was constructed of Bell Canyon to highlight watershed characteristics and each's effect on runoff. The physical model offers a comprehensive visualization of a natural watershed and can vary the characteristics of rainfall intensity, slope, and roughness through interchangeable parts and adjustments to the system. The scaled physical model is validated and calibrated through a HEC-HMS model to assure similitude of the system. Preliminary results of the physical model suggest that a 50-year storm event can be represented by a peak discharge of 2.2 X 10-3 cfs. When comparing the results to HEC-HMS, this equates to a flow relationship of approximately 1:160,000, which can be used to model other return periods. The completion of the Bell Canyon physical model can be used for educational instruction in the classroom, outreach in the community, and further research using the model as an accurate representation of the watershed present in the San Dimas Experimental Forest.

The effects of different opacifiers on the translucency of experimental dental composite resins.

PubMed

Haas, Karine; Azhar, Gulelala; Wood, Duncan J; Moharamzadeh, Keyvan; van Noort, Richard

2017-08-01

The aim of this study was to evaluate the effects of different opacifiers on the translucency of experimental dental composite-resins. Three metal oxides that are used as opacifiers were tested in this study: titanium oxide (TiO 2 ), aluminium oxide (Al 2 O 3 ) and zirconium oxide (ZrO 2 ). Experimental composite-resins were fabricated containing 25wt.% urethane dimethacrylate (UDMA)-based resin matrix and 75% total filler including different concentrations of metal oxides (0, 0.25, 0.5, 0.75 and 1wt.%) blended into silane treated barium-silicate filler. The specimens (15.5mm diameter and 1mm thickness) were light-cured and tested in the transmittance mode using a UV/VIS spectrophotometer at wavelengths from 380 to 700nm under a standard illuminant D65. The color differences (ΔE* ab) between different concentrations of opacifiers were also measured in transmittance mode based on their Lab values. Statistical analysis by ANOVA and Tukey's test showed a significant decrease (p<0.05) in light transmittance with the addition of opacifiers to the experimental composite-resins. There was a linear correlation between different concentrations of TiO 2 and Al 2 O 3 and total transmittance. Total transmittance was also found to be wavelength dependent. The color differences for the concentrations of 0-1wt.% of the opacifiers were above 1 ΔE* unit, with Al 2 O 3 showing the smallest color shift. The type and the amount of the opacifiers used in this study had a significant effect on the translucency of the experimental UDMA-based dental composite resins. The most effective opacifier was TiO 2 , followed by ZrO 2 and Al 2 O 3 in decreasing order, respectively. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Quality of nursing diagnoses: evaluation of an educational intervention.

PubMed

Florin, Jan; Ehrenberg, Anna; Ehnfors, Margareta

2005-01-01

To investigate the effects on the quality of nursing diagnostic statements in patient records after education in the nursing process and implementation of new forms for recording. Quasi-experimental design. Randomly selected patient records reviewed before and after intervention from one experimental unit (n = 70) and three control units (n = 70). A scale with 14 characteristics pertaining to nursing diagnoses was developed and used together with the instrument (CAT-CH-ING) for record review. Quality of nursing diagnostic statements improved in the experimental unit, whereas no improvement was found in the control units. Serious flaws in the use of the etiology component were found. CONCLUSION. Nurses must be more concerned with the accuracy and quality of the nursing diagnoses and the etiology component needs to be given special attention. Education of RNs in nursing diagnostic statements and peer review using standardized evaluation instruments can be means to further enhance RNs' documentation practice.

A Low Cost Environmentally Benign Waste Lubricants Recycling/Re-refining Technology.

DTIC Science & Technology

1999-05-01

EXPERIMENTAL 3 2.1 Ceramic Membrane Ultrafiltration Pilot Unit 3 2.2 Polishing/Finishing Pilot Unit 3 2.3 Feed Samples 3 2.4 Sample...development of an additional 2 to 3 sites in the US. 2. EXPERIMENTAL 2.1. Ceramic Membrane Ultrafiltration Pilot Unit A photograph of the pilot...scale ceramic membrane system used in this work is shown in Figure la. Samples of spent turbine oil were charged to the feed tank and heated to 150°C

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

Forman, S. E.; Themelis, M. P.

The Department of Energy has set a 20-year lifetime goal for terrestrial photovoltaic modules. Massachusetts Institute of Technology's Lincoln Laboratory, in its capacity as a Photovoltaic Field Tests and Applications Center, has established various experimental test sites in the United States ranging in size from 0.1 to 25 kW of peak power. These sites serve as test beds for photovoltaic system components and include modules from several manufacturers. This report summarizes the activities of the Materials, Processes and Testing Laboratory of the Solar Photovoltaic Project during a three-month (10/1/78--12/31/78) period. Particular attention is given to testing and analysis of solarmore » modules from the Mead, Nebraska site, which contains a 25-kW array. A trip to the site was made, where various testing and inspection procedures were followed, in order to ascertain the physical and electrical degradation which had occurred in modules. In addition, several modules were removed for more detailed testing and inspection in the Laboratory. The results of both the field testing and laboratory analyses are reported here.« less

Efficacy of clade 2.3.2 H5 commercial vaccines in protecting chickens from clade 2.3.4.4 H5N8 highly pathogenic avian influenza infection.

PubMed

Yuk, Seong-Su; Erdene-Ochir, T O; Kwon, Jung-Hoon; Noh, Jin-Yong; Hong, Woo-Tack; Jeong, Jei-Hyun; Jeong, Sol; Gwon, Gyeong-Bin; Shin, Jong-Il; Sur, Jung-Hyang; Song, Chang-Seon

2017-03-01

Emerging clade 2.3.4.4 of the highly pathogenic avian influenza (HPAI) virus strain H5N8, which had been detected sporadically in domestic poultry in China, started to affect wild birds and poultry in South Korea in 2014. The virus was spread to Germany, Italy, the Netherlands, United Kingdom, and even United States by migratory birds. Here, we tested currently used commercial clade 2.3.2 H5 vaccines to evaluate mortality, clinical signs, virus shedding, and histological damage after experimental infection of chickens with the clade 2.3.4.4 HPAI H5N8 virus. Although the vaccination protected chickens from death, it failed to prevent chickens from shedding the virus and from tissue damage according to histological examination. These results suggest that the use of appropriate vaccines that match the currently epidemic HPAI virus is recommended, and continuous HPAI surveillance and testing of currently used commercial vaccines should be performed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Carbachol dimers as homobivalent modulators of muscarinic receptors.

PubMed

Matucci, Rosanna; Nesi, Marta; Martino, Maria Vittoria; Bellucci, Cristina; Manetti, Dina; Ciuti, Elisa; Mazzolari, Angelica; Dei, Silvia; Guandalini, Luca; Teodori, Elisabetta; Vistoli, Giulio; Romanelli, Maria Novella

2016-05-15

A series of homodimers of the well-known cholinergic agonist carbachol have been synthesized, showing the two agonist units symmetrically connected through a methylene chain of variable length. The new compounds have been tested on the five cloned muscarinic receptors (hM1-5) expressed in CHO cells by means of equilibrium binding studies, showing an increase in affinity by rising the number of methylene units up to 7 and 9. Functional experiments on guinea-pig ileum and assessment of ERK1/2 phosphorylation on hM1, hM2 and hM3 on CHO cells have shown that the new compounds are endowed with muscarinic antagonistic properties. Kinetic binding studies have revealed that some of the tested compounds are able to slow the rate of dissociation of NMS, suggesting a bitopic behavior. Docking simulations, performed on the hM1 and hM2 receptors, give a sound rationalization of the experimental data revealing how these compounds are able to interact with both orthosteric and allosteric binding sites depending on the length of their connecting chain. Copyright © 2016 Elsevier Inc. All rights reserved.

A Test for Anchoring and Yea-Saying in Experimental Consumption Data.

PubMed

van Soest, Arthur; Hurd, Michael

2008-01-01

We analyze experimental survey data, with a random split into respondents who get an open-ended question on the amount of total family consumption (with follow-up unfolding brackets of the form "Is consumption $X or more?" for those who answer "don't know" or "refuse") and respondents who are immediately directed to unfolding brackets. In both cases, the entry point of the unfolding bracket sequence is randomized. Allowing for any type of selection into answering the open-ended or bracket questions, a nonparametric test is developed for errors in the answers to the first bracket question that are different from the usual reporting errors that will also affect open-ended answers. Two types of errors are considered explicitly: anchoring and yea-saying. Data are collected in the 1995 wave of the Assets and Health Dynamics survey, which is representative of the population in the United States that is 70 years and older. We reject the joint hypothesis of no anchoring and no yea-saying. Once yea-saying is taken into account, we find no evidence of anchoring at the entry point.

A Test for Anchoring and Yea-Saying in Experimental Consumption Data

PubMed Central

van Soest, Arthur; Hurd, Michael

2017-01-01

We analyze experimental survey data, with a random split into respondents who get an open-ended question on the amount of total family consumption (with follow-up unfolding brackets of the form “Is consumption $X or more?” for those who answer “don’t know” or “refuse”) and respondents who are immediately directed to unfolding brackets. In both cases, the entry point of the unfolding bracket sequence is randomized. Allowing for any type of selection into answering the open-ended or bracket questions, a nonparametric test is developed for errors in the answers to the first bracket question that are different from the usual reporting errors that will also affect open-ended answers. Two types of errors are considered explicitly: anchoring and yea-saying. Data are collected in the 1995 wave of the Assets and Health Dynamics survey, which is representative of the population in the United States that is 70 years and older. We reject the joint hypothesis of no anchoring and no yea-saying. Once yea-saying is taken into account, we find no evidence of anchoring at the entry point. PMID:29056797

Software and mathematical support of Kazakhstani star tracker

NASA Astrophysics Data System (ADS)

Akhmedov, D.; Yelubayev, S.; Ten, V.; Bopeyev, T.; Alipbayev, K.; Sukhenko, A.

2016-10-01

Currently the specialists of Kazakhstan have been developing the star tracker that is further planned to use on Kazakhstani satellites of various purposes. At the first stage it has been developed the experimental model of star tracker that has following characteristics: field of view 20°, update frequency 2 Hz, exclusion angle 40°, accuracy of attitude determination of optical axis/around optical axis 15/50 arcsec. Software and mathematical support are the most high technology parts of star tracker. The results of software and mathematical support development of experimental model of Kazakhstani star tracker are represented in this article. In particular, there are described the main mathematical models and algorithms that have been used as a basis for program units of preliminary image processing of starry sky, stars identification and star tracker attitude determination. The results of software and mathematical support testing with the help of program simulation complex using various configurations of defects including image sensor noises, point spread function modeling, optical system distortion up to 2% are presented. Analysis of testing results has shown that accuracy of attitude determination of star tracker is within the permissible range

The Role of Formal Experiment Design in Hypersonic Flight System Technology Development

NASA Technical Reports Server (NTRS)

McClinton, Charles R.; Ferlemann, Shelly M.; Rock, Ken E.; Ferlemann, Paul G.

2002-01-01

Hypersonic airbreathing engine (scramjet) powered vehicles are being considered to replace conventional rocket-powered launch systems. Effective utilization of scramjet engines requires careful integration with the air vehicle. This integration synergistically combines aerodynamic forces with propulsive cycle functions of the engine. Due to the highly integrated nature of the hypersonic vehicle design problem, the large flight envelope, and the large number of design variables, the use of a statistical design approach in design is effective. Modern Design-of-Experiments (MDOE) has been used throughout the Hyper-X program, for both systems analysis and experimental testing. Application of MDOE fall into four categories: (1) experimental testing; (2) studies of unit phenomena; (3) refining engine design; and (4) full vehicle system optimization. The MDOE process also provides analytical models, which are also used to document lessons learned, supplement low-level design tools, and accelerate future studies. This paper will discuss the design considerations for scramjet-powered vehicles, specifics of MDOE utilized for Hyper-X, and present highlights from the use of these MDOE methods within the Hyper-X Program.

Experimental and Analytical Performance of a Dual Brayton Power Conversion System

NASA Technical Reports Server (NTRS)

Lavelle, Thomas A.; Hervol, David S.; Briggs, Maxwell; Owen, A. Karl

2009-01-01

The interactions between two closed Brayton cycle (CBC) power conversion units (PCU) which share a common gas inventory and heat source have been studied experimentally using the Dual Brayton Power Conversion System (DBPCS) and analytically using the Closed- Cycle System Simulation (CCSS) computer code. Selected operating modes include steady-state operation at equal and unequal shaft speeds and various start-up scenarios. Equal shaft speed steady-state tests were conducted for heater exit temperatures of 840 to 950 K and speeds of 50 to 90 krpm, providing a system performance map. Unequal shaft speed steady-state testing over the same operating conditions shows that the power produced by each Brayton is sensitive to the operating conditions of the other due to redistribution of gas inventory. Startup scenarios show that starting the engines one at a time can dramatically reduce the required motoring energy. Although the DBPCS is not considered a flight-like system, these insights, as well as the operational experience gained from operating and modeling this system provide valuable information for the future development of Brayton systems.

Using a handbook to improve nurses' continence care.

PubMed

Williams, K; Roe, B; Sindhu, F

Nursing care should be based on sound research evidence with demonstrated clinical effectiveness. Dissemination of this research evidence is, therefore, of paramount importance. A study using focus groups was undertaken during 1993-1994 to evaluate the dissemination of a clinical handbook for continence care to qualified nurses, in relation to reported nursing practice in care of the elderly wards/units in one health authority. A total of 124 nurses participated in the study and 98 variables were included. Improvements were recorded in nurses' responses between the pre-test and post-test for 84 (86 per cent) variables in the experimental group and 58 (59 per cent) in the control group. This demonstrates the positive value of the clinical handbook as a method of disseminating research evidence.

Preliminary design of mesoscale turbocompressor and rotordynamics tests of rotor bearing system

NASA Astrophysics Data System (ADS)

Hossain, Md Saddam

2011-12-01

A mesoscale turbocompressor spinning above 500,000 RPM is evolutionary technology for micro turbochargers, turbo blowers, turbo compressors, micro-gas turbines, auxiliary power units, etc for automotive, aerospace, and fuel cell industries. Objectives of this work are: (1) to evaluate different air foil bearings designed for the intended applications, and (2) to design & perform CFD analysis of a micro-compressor. CFD analysis of shrouded 3-D micro compressor was conducted using Ansys Bladegen as blade generation tool, ICEM CFD as mesh generation tool, and CFX as main solver for different design and off design cases and also for different number of blades. Comprehensive experimental facilities for testing the turbocompressor system have been also designed and proposed for future work.

Benchmarking density functional theory predictions of framework structures and properties in a chemically diverse test set of metal-organic frameworks

DOE PAGES

Nazarian, Dalar; Ganesh, P.; Sholl, David S.

2015-09-30

We compiled a test set of chemically and topologically diverse Metal–Organic Frameworks (MOFs) with high accuracy experimentally derived crystallographic structure data. The test set was used to benchmark the performance of Density Functional Theory (DFT) functionals (M06L, PBE, PW91, PBE-D2, PBE-D3, and vdW-DF2) for predicting lattice parameters, unit cell volume, bonded parameters and pore descriptors. On average PBE-D2, PBE-D3, and vdW-DF2 predict more accurate structures, but all functionals predicted pore diameters within 0.5 Å of the experimental diameter for every MOF in the test set. The test set was also used to assess the variance in performance of DFT functionalsmore » for elastic properties and atomic partial charges. The DFT predicted elastic properties such as minimum shear modulus and Young's modulus can differ by an average of 3 and 9 GPa for rigid MOFs such as those in the test set. Moreover, we calculated the partial charges by vdW-DF2 deviate the most from other functionals while there is no significant difference between the partial charges calculated by M06L, PBE, PW91, PBE-D2 and PBE-D3 for the MOFs in the test set. We find that while there are differences in the magnitude of the properties predicted by the various functionals, these discrepancies are small compared to the accuracy necessary for most practical applications.« less

Design, construction, and operation of an actively controlled deep-sea CO2 enrichment experiment using a cabled observatory system

NASA Astrophysics Data System (ADS)

Kirkwood, William J.; Walz, Peter M.; Peltzer, Edward T.; Barry, James P.; Herlien, Robert A.; Headley, Kent L.; Kecy, Chad; Matsumoto, George I.; Maughan, Thom; O'Reilly, Thomas C.; Salamy, Karen A.; Shane, Farley; Brewer, Peter G.

2015-03-01

We describe the design, testing, and performance of an actively controlled deep-sea Free Ocean CO2 Enrichment (dp-FOCE) system for the execution of seafloor experiments relating to the impacts of ocean acidification on natural ecosystems. We used the 880 m deep MARS (Monterey Accelerated Research System) cable site offshore Monterey Bay, California for this work, but the Free Ocean CO2 Enrichment (FOCE) system concept is designed to be scalable and can be modified to be used in a wide variety of ocean depths and locations. The main frame is based on a flume design with active thruster control of flow and a central experimental chamber. The unit was allowed to free fall to the seafloor and connected to the cable node by remotely operated vehicle (ROV) manipulation. For operation at depth we designed a liquid CO2 containment reservoir which provided the CO2 enriched working fluid as ambient seawater was drawn through the reservoir beneath the more buoyant liquid CO2. Our design allowed for the significant lag time associated with the hydration of the dissolved CO2 molecule, resulting in an e-folding time, τ, of 97 s between fluid injection and pH sensing at the mean local T=4.31±0.14 °C and pHT of 7.625±0.011. The system maintained a pH offset of 0.4 pH units compared to the surrounding ocean for a period of 1 month. The unit allows for the emplacement of deep-sea animals for testing. We describe the components and software used for system operation and show examples of each. The demonstrated ability for active control of experimental systems opens new possibilities for deep-sea biogeochemical perturbation experiments of several kinds and our developments in open source control systems software and hardware described here are applicable to this end.

A Case Study on Teaching the Topic "Experimental Unit" and How It Is Presented in Advanced Placement Statistics Textbooks

ERIC Educational Resources Information Center

Perrett, Jamis J.

2012-01-01

This article demonstrates how textbooks differ in their description of the term "experimental unit". Advanced Placement Statistics teachers and students are often limited in their statistical knowledge by the information presented in their classroom textbook. Definitions and descriptions differ among textbooks as well as among different…

A 7.4 ps FPGA-Based TDC with a 1024-Unit Measurement Matrix

PubMed Central

Zhang, Min; Wang, Hai; Liu, Yan

2017-01-01

In this paper, a high-resolution time-to-digital converter (TDC) based on a field programmable gate array (FPGA) device is proposed and tested. During the implementation, a new architecture of TDC is proposed which consists of a measurement matrix with 1024 units. The utilization of routing resources as the delay elements distinguishes the proposed design from other existing designs, which contributes most to the device insensitivity to variations of temperature and voltage. Experimental results suggest that the measurement resolution is 7.4 ps, and the INL (integral nonlinearity) and DNL (differential nonlinearity) are 11.6 ps and 5.5 ps, which indicates that the proposed TDC offers high performance among the available TDCs. Benefitting from the FPGA platform, the proposed TDC has superiorities in easy implementation, low cost, and short development time. PMID:28420121

German-Korean cooperation for erection and test of industrialized solar technologies

NASA Astrophysics Data System (ADS)

Pfeiffer, H.

1986-01-01

A combined small solar-wind power station and a solar-thermal experimental plant were built. The plants are designed to demonstrate the effective exploitation of solar energy and wind energy and enhanced availability achievable through combination of these two energy sources. A 14 kW wind energy converter and a 2.5 kW solar-cell generator were operated in parallel. The biaxial tracking system used on the solar generator leads to increased and constant generation of electricity throughout the day. A consumer control system switches the energy generators and the consumers in autonomous mode according to changing supply and demand. The solar powered air conditioning unit operates with an absorption type refrigerating unit, high-output flat collectors and an automatic control system. All design values are achieved on start-up of the plant.

A 7.4 ps FPGA-Based TDC with a 1024-Unit Measurement Matrix.

PubMed

Zhang, Min; Wang, Hai; Liu, Yan

2017-04-14

In this paper, a high-resolution time-to-digital converter (TDC) based on a field programmable gate array (FPGA) device is proposed and tested. During the implementation, a new architecture of TDC is proposed which consists of a measurement matrix with 1024 units. The utilization of routing resources as the delay elements distinguishes the proposed design from other existing designs, which contributes most to the device insensitivity to variations of temperature and voltage. Experimental results suggest that the measurement resolution is 7.4 ps, and the INL (integral nonlinearity) and DNL (differential nonlinearity) are 11.6 ps and 5.5 ps, which indicates that the proposed TDC offers high performance among the available TDCs. Benefitting from the FPGA platform, the proposed TDC has superiorities in easy implementation, low cost, and short development time.

Instrument performance of a radon measuring system with the alpha-track detection technique.

PubMed

Tokonami, S; Zhuo, W; Ryuo, H; Yonehara, H; Yamada, Y; Shimo, M

2003-01-01

An instrument performance test has been carried out for a radon measuring system made in Hungary. The system measures radon using the alpha-track detection technique. It consists of three parts: the passive detector, the etching unit and the evaluation unit. A CR-39 detector is used as the radiation detector. Alpha-track reading and data analysis are carried out after chemical etching. The following subjects were examined in the present study: (1) radon sensitivity, (2) performance of etching and evaluation processes and (3) thoron sensitivity. The radon sensitivity of 6.9 x 10(-4) mm(-2) (Bq m(-3) d)(-1) was acceptable for practical application. The thoron sensitivity was estimated to be as low as 3.3 x 10(-5) mm(-2) (Bq m(-3) d)(-1) from the experimental study.

Optical lenses design and experimental investigations of a dynamic focusing unit for a CO2 laser scanning system

NASA Astrophysics Data System (ADS)

Chen, Wei; Xu, Yue; Zhang, Huaxin; Liu, Peng; Jiao, Guohua

2016-09-01

Laser scanners are critical components in material processing systems, such as welding, cutting, and drilling. To achieve high-accuracy processing, the laser spot size should be small and uniform in the entire objective flat field. However, traditional static focusing method using F-theta objective lens is limited by the narrow flat field. To overcome these limitations, a dynamic focusing unit consisting of two lenses is presented in this paper. The dual-lens system has a movable plano-concave lens and a fixed convex lens. As the location of the movable optical elements is changed, the focal length is shifted to keep a small focus spot in a broad flat processing filed. The optical parameters of the two elements are theoretical analyzed. The spot size is calculated to obtain the relationship between the moving length of first lens and the shift focus length of the system. Also, the Zemax model of the optical system is built up to verify the theoretical design and optimize the optical parameter. The proposed lenses are manufactured and a test system is built up to investigate their performances. The experimental results show the spot size is smaller than 450um in all the 500*500mm 2 filed with CO2 laser. Compared with the other dynamic focusing units, this design has fewer lenses and no focusing spot in the optical path. In addition, the focal length minimal changes with the shit of incident laser beam.

Family relations and eating disorders. The effectiveness of an integrated approach in the treatment of anorexia and bulimia in teenagers: results of a case-control systemic research.

PubMed

Onnis, L; Barbara, E; Bernardini, M; Caggese, A; Di Giacomo, S; Giambartolomei, A; Leonelli, A; Mule', A M; Nicoletti, P G; Vietri, A

2012-03-01

This article presents the results of a broader clinical research into the effectiveness of integrated treatments in teenage eating disorders, carried out at the Complex Operative Unit of Psychotherapy (Unità Operativa Complessa or U.O.C.) of the Department of Psychiatric Sciences and Psychological Medicine in collaboration with the Department of Neuropsychiatric Science for Child Development (Dipartimento di Scienze Neuropsichiatriche dell'Età Evolutiva), both at the "La Sapienza" University of Rome. The hypothesis of this research project is that in diagnosticable situations such as anorexia or bulimia, an integrated and multidisciplinary treatment, which combines medical-nutritional interventions and family psychotherapy, allows better results than a single kind of treatment, which is the usual medical- nutritional intervention supported by psychiatric counselling. Twenty-eight cases (16 of bulimia and 12 of anorexia) were selected and then subdivided, with a randomized distribution, into two (experimental and control) homogeneous groups of 14 patients. The grouping variables were the diagnosis, the disorder's seriousness and duration, BMI, gender, age, family composition and social status. The variables which have been examined in this article are the clinical parameters, which were valuated in accordance with the DSM IV-TR criteria, and relational parameters which were explored through the use of the W.F.T. Test (Wiltwyck Family Tasks). These parameters were tested at beginning as well as at the end of the therapies, in both the experimental group and the control group. Statistical analysis has shown that the experimental group, which was followed with the integrated treatment, experienced a significant improvement of the parameters as related to dysfunctional family interaction modalities, and that this improvement was correlated to the positive evolution of the clinical parameters. This improvement was not present or not of the same degree in the control group. The results, moreover, demonstrate the effectiveness of an integrated systemic treatment based on a complex approach compared to a reductionist approach.

Temperature prediction of space flight experiments by computer thermal analysis

NASA Technical Reports Server (NTRS)

Birdsong, M. B.; Luttges, M. W.

1994-01-01

Life sciences experiments are especially sensitive to temperature. A small temperature difference between otherwise identical samples can cause various differences in biological reaction rates. Knowledge of experimental temperatures and temperature histories help to distinguish the effects of microgravity and temperature on spaceflight experiments compared to ground based studies, and allow appropriate controls and sensitivity tests. Up to the present time, the Orbiter (Space Shuttle) has not generally provided temperature measurement instrumentation inside ambient lockers located in the Mid-deck of the Orbiter, or inside similar facilities such as Spacehab and Spacelab, but many pieces of hardware do have temperature recording capability. Most of these temperatures, however, have only been roughly measured or estimated. Such reported experimental temperatures, while accurate within a range of several degrees Celsius, are of limited utility to biological researchers. The temperature controlled lockers used in spaceflight, such as Commerical-Refrigeration Incubation Modules (C-R/IMs), severely reduce the mass and volume available for test samples and do not necessarily provide uniform thermal environments. While these test carriers avoid some of the experimental temperature variations of the ambient lockers, the number of samples which can be accommodated in these temperature controlled units is limited. In the present work, improved models of thermal prediction and control were sought. Temperatures are predicted by thermal analysis software using empirical temperatures recorded during STS-57. These temperatures are compared to data recorded throughout the mission using Ambient Temperature Recorders (ATRs) located within several payload lockers. Additional test cases are undertaken using controlled ground experiments to more precisely determine the reliability of the thermal model. The approach presented should increase the utility of various spaceflight carriers in the support of biological and material science research and ground control studies done in preparation for flight.

Temperature prediction of space flight experiments by computer thermal analysis.

PubMed

Birdsong, M B; Luttges, M W

1995-02-01

Life sciences experiments are especially sensitive to temperature. A small temperature difference between otherwise identical samples can cause various differences in biological reaction rates. Knowledge of experimental temperatures and temperature histories help to distinguish the effects of microgravity and temperature on spaceflight experiments compared to ground based studies, and allow appropriate controls and sensitivity tests. Up to the present time, the Orbiter (Space Shuttle) has not generally provided temperature measurement instrumentation inside ambient lockers located in the Mid-deck of the Orbiter, or inside similar facilities such as Spacehab and Spacelab, but many pieces of hardware do have temperature recording capability. Most of these temperatures, however, have only been roughly measured or estimated. Such reported experimental temperatures, while accurate within a range of several degrees Celsius, are of limited utility to biological researchers. The temperature controlled lockers used in spaceflight, such as Commercial-Refrigeration Incubation Modules (C-R/IMs), severely reduce the mass and volume available for test samples and do not necessarily provide uniform thermal environments. While these test carriers avoid some of the experimental temperature variations of the ambient lockers, the number of samples which can be accommodated in these temperature controlled units is limited. In the present work, improved models of thermal prediction and control were sought. Temperatures are predicted by thermal analysis software using empirical temperatures recorded during STS-57. These temperatures are compared to data recorded throughout the mission using Ambient Temperature Recorders (ATRs) located within several payload lockers. Additional test cases are undertaken using controlled ground experiments to more precisely determine the reliability of the thermal model. The approach presented should increase the utility of various spaceflight carriers in the support of biological and material science research and ground control studies done in preparation for flight.

Large-scale neural circuit mapping data analysis accelerated with the graphical processing unit (GPU).

PubMed

Shi, Yulin; Veidenbaum, Alexander V; Nicolau, Alex; Xu, Xiangmin

2015-01-15

Modern neuroscience research demands computing power. Neural circuit mapping studies such as those using laser scanning photostimulation (LSPS) produce large amounts of data and require intensive computation for post hoc processing and analysis. Here we report on the design and implementation of a cost-effective desktop computer system for accelerated experimental data processing with recent GPU computing technology. A new version of Matlab software with GPU enabled functions is used to develop programs that run on Nvidia GPUs to harness their parallel computing power. We evaluated both the central processing unit (CPU) and GPU-enabled computational performance of our system in benchmark testing and practical applications. The experimental results show that the GPU-CPU co-processing of simulated data and actual LSPS experimental data clearly outperformed the multi-core CPU with up to a 22× speedup, depending on computational tasks. Further, we present a comparison of numerical accuracy between GPU and CPU computation to verify the precision of GPU computation. In addition, we show how GPUs can be effectively adapted to improve the performance of commercial image processing software such as Adobe Photoshop. To our best knowledge, this is the first demonstration of GPU application in neural circuit mapping and electrophysiology-based data processing. Together, GPU enabled computation enhances our ability to process large-scale data sets derived from neural circuit mapping studies, allowing for increased processing speeds while retaining data precision. Copyright © 2014 Elsevier B.V. All rights reserved.

A controlled experiment to evaluate the impact of summer research experiences on attitudes towards science in high school aged students

NASA Astrophysics Data System (ADS)

White, M. A.; Tcherednichenko, I.; Hamar, M.; Taylor, M. J.; Litizzette, L.

2006-12-01

United States funding agencies increasingly are supporting activities designed to increase the enrollment of United States high school students in science, math, or engineering careers. However, in many cases, the likely outcomes of educational activities are unknown. A common approach within the physical and natural sciences is to provide high school aged students with a summer research experience, with the expectation that such experiences will increase student interest in science, possibly as a career choice. With funding support from the National Aeronautics and Space Administration New Investigator Grant program, we conducted a controlled experiment to test this assumption. In collaboration with Mountain Crest High School in Logan, UT, we recruited 40 students currently enrolled in science courses, assessed attitudes towards science (with informed consent), and randomly assigned 20 students to a control group and 20 students to an experimental group. Students in the experimental group were paired with faculty and graduate students in a wide range of field and laboratory research groups in natural resources and biology. Students were employed in at least two different research groups for an average of 30-40 hours per week for eight weeks in the summer of 2006. Following the completion of the summer work experience, we again assessed attitudes towards science in both groups and gathered additional information from the experimental group on satisfaction with the work experience and reasons for participating. Results are presented and discussed.

Large scale neural circuit mapping data analysis accelerated with the graphical processing unit (GPU)

PubMed Central

Shi, Yulin; Veidenbaum, Alexander V.; Nicolau, Alex; Xu, Xiangmin

2014-01-01

Background Modern neuroscience research demands computing power. Neural circuit mapping studies such as those using laser scanning photostimulation (LSPS) produce large amounts of data and require intensive computation for post-hoc processing and analysis. New Method Here we report on the design and implementation of a cost-effective desktop computer system for accelerated experimental data processing with recent GPU computing technology. A new version of Matlab software with GPU enabled functions is used to develop programs that run on Nvidia GPUs to harness their parallel computing power. Results We evaluated both the central processing unit (CPU) and GPU-enabled computational performance of our system in benchmark testing and practical applications. The experimental results show that the GPU-CPU co-processing of simulated data and actual LSPS experimental data clearly outperformed the multi-core CPU with up to a 22x speedup, depending on computational tasks. Further, we present a comparison of numerical accuracy between GPU and CPU computation to verify the precision of GPU computation. In addition, we show how GPUs can be effectively adapted to improve the performance of commercial image processing software such as Adobe Photoshop. Comparison with Existing Method(s) To our best knowledge, this is the first demonstration of GPU application in neural circuit mapping and electrophysiology-based data processing. Conclusions Together, GPU enabled computation enhances our ability to process large-scale data sets derived from neural circuit mapping studies, allowing for increased processing speeds while retaining data precision. PMID:25277633

Research on electrodischarge drilling of polycrystalline diamond with increased gap voltage

NASA Astrophysics Data System (ADS)

Skoczypiec, Sebastian; Bizoń, Wojciech; Żyra, Agnieszka

2018-05-01

This paper presents an experimental investigation of the machining characteristics of polycrystalline diamond (PCD). Machining of PCD by conventional technologies is not an effective solution. Due to presence of cobalt this material can be machined by application of electrical discharges. On the other side, electrical conductivity of PCD is on the limit of electrodischarge machining (EDM) possibilities. Proposed paper reports experimental investigation on electrodischarge drilling of PCD samples. The test were carried out with application on of high-voltage (up to 550 V) pulse power unit for two kinds of dielectrics: carbon based (Exxsol D80) and de-ionized water. As output parameters machining accuracy (side gap), material removal rate were selected. Also, based on SEM photographs and energy dispersive X-ray spectroscopy (EDS) analysis, a qualitative evaluation of the obtained results was presented.

The impact of retirement on health: quasi-experimental methods using administrative data.

PubMed

Horner, Elizabeth Mokyr; Cullen, Mark R

2016-02-19

Is retirement good or bad for health? Disentangling causality is difficult. Much of the previous quasi-experimental research on the effect of health on retirement used self-reported health and relied upon discontinuities in public retirement incentives across Europe. The current study investigated the effect of retirement on health by exploiting discontinuities in private retirement incentives to test the effect of retirement on health using a quasi-experimental study design. Secondary data (1997-2009) on a cohort of male manufacturing workers in a United States setting. Health status was determined using claims data from private insurance and Medicare. Analyses used employer-based administrative and claims data and claim data from Medicare. Widely used selection on observables models overstate the negative impact of retirement due to the endogeneity of the decision to retire. In addition, health status as measured by administrative claims data provide some advantages over the more commonly used survey items. Using an instrument and administrative health records, we find null to positive effects from retirement on all fronts, with a possible exception of increased risk for diabetes. This study provides evidence that retirement is not detrimental and may be beneficial to health for a sample of manufacturing workers. In addition, it supports previous research indicating that quasi-experimental methodologies are necessary to evaluate the relationship between retirement and health, as any selection on observable model will overstate the negative relationship of retirement on health. Further, it provides a model for how such research could be implemented in countries like the United States that do not have a strong public pension program. Finally, it demonstrates that such research need-not rely upon survey data, which has certain shortcomings and is not always available for homogenous samples.

Analytical and experimental study of sleeper SAT S 312 in slab track Sateba system

NASA Astrophysics Data System (ADS)

Guigou-Carter, C.; Villot, M.; Guillerme, B.; Petit, C.

2006-06-01

In this paper, a simple prediction tool based on a two-dimensional model is developed for a slab track system composed of two rails with rail pads, sleepers with sleeper pads, and a concrete base slab. The track and the slab are considered as infinite beams with bending stiffness, loss factor and mass per unit length. The track system is represented by its impedance per unit length of track and the ground by its line input impedance calculated using a two-dimensional elastic half-space ground model based on the wave approach. Damping of each track component is modelled as hysteretic damping and is taken into account by using a complex stiffness. The unsprung mass of the vehicle is considered as a concentrated mass at the excitation point on the rail head. The effect of the dynamic stiffness of the sleeper pads on the vibration isolation is studied in detail, the vibration isolation provided by the track system being quantified by an insertion gain in dB per one-third octave band. The second part of this paper presents an experimental test rig used to measure the dynamic stiffness of the sleeper pads on a full width section of the track (two rails). The experimental set-up is submitted to vertical as well as horizontal static loads (via hydraulic jacks) and an electrodynamic shaker is used for dynamic excitation of the system. The determination of the dynamic stiffness of the sleeper pads is based on the approach called the "direct method". The limitations of the experimental set-up are discussed. The measurement results for one type of sleeper pad are presented.

Simplified Estimation and Testing in Unbalanced Repeated Measures Designs.

PubMed

Spiess, Martin; Jordan, Pascal; Wendt, Mike

2018-05-07

In this paper we propose a simple estimator for unbalanced repeated measures design models where each unit is observed at least once in each cell of the experimental design. The estimator does not require a model of the error covariance structure. Thus, circularity of the error covariance matrix and estimation of correlation parameters and variances are not necessary. Together with a weak assumption about the reason for the varying number of observations, the proposed estimator and its variance estimator are unbiased. As an alternative to confidence intervals based on the normality assumption, a bias-corrected and accelerated bootstrap technique is considered. We also propose the naive percentile bootstrap for Wald-type tests where the standard Wald test may break down when the number of observations is small relative to the number of parameters to be estimated. In a simulation study we illustrate the properties of the estimator and the bootstrap techniques to calculate confidence intervals and conduct hypothesis tests in small and large samples under normality and non-normality of the errors. The results imply that the simple estimator is only slightly less efficient than an estimator that correctly assumes a block structure of the error correlation matrix, a special case of which is an equi-correlation matrix. Application of the estimator and the bootstrap technique is illustrated using data from a task switch experiment based on an experimental within design with 32 cells and 33 participants.

The widespread misuse of effect sizes.

PubMed

Dankel, Scott J; Mouser, J Grant; Mattocks, Kevin T; Counts, Brittany R; Jessee, Matthew B; Buckner, Samuel L; Loprinzi, Paul D; Loenneke, Jeremy P

2017-05-01

Studies comparing multiple groups (i.e., experimental and control) often examine the efficacy of an intervention by calculating within group effect sizes using Cohen's d. This method is inappropriate and largely impacted by the pre-test variability as opposed to the variability in the intervention itself. Furthermore, the percentage change is often analyzed, but this is highly impacted by the baseline values and can be potentially misleading. Thus, the objective of this study was to illustrate the common misuse of the effect size and percent change measures. Here we provide a realistic sample data set comparing two resistance training groups with the same pre-test to post-test change. Statistical tests that are commonly performed within the literature were computed. Analyzing the within group effect size favors the control group, while the percent change favors the experimental group. The most appropriate way to present the data would be to plot the individual responses or, for larger samples, provide the mean change and 95% confidence intervals of the mean change. This details the magnitude and variability within the response to the intervention itself in units that are easily interpretable. This manuscript demonstrates the common misuse of the effect size and details the importance for investigators to always report raw values, even when alternative statistics are performed. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Development of a compact HTS lead unit for the SC correction coils of the SuperKEKB final focusing magnet system

NASA Astrophysics Data System (ADS)

Zong, Zhanguo; Ohuchi, Norihito; Tsuchiya, Kiyosumi; Arimoto, Yasushi

2016-09-01

Forty-three superconducting (SC) correction coils with maximum currents of about 60 A are installed in the SuperKEKB final focusing magnet system. Current leads to energize the SC correction coils should have an affordable heat load and fit the spatial constraints in the service cryostat where the current leads are installed. To address the requirements, design optimization of individual lead was performed with vapor cooled current lead made of a brass material, and a compact unit was designed to accommodate eight current leads together in order to be installed with one port in the service cryostat. The 2nd generation high temperature SC (HTS) tape was adopted and soldered at the cold end of the brass current lead to form a hybrid HTS lead structure. A prototype of the compact lead unit with HTS tape was constructed and tested with liquid helium (LHe) environment. This paper presents a cryogenic measurement system to simulate the real operation conditions in the service cryostat, and analysis of the experimental results. The measured results showed excellent agreement with the theoretical analysis and numerical simulation. In total, 11 sets of the compact HTS lead units were constructed for the 43 SC correction coils at KEK. One set from the mass production was tested in cryogenic conditions, and exhibited the same performance as the prototype. The compact HTS lead unit can feed currents to four SC correction coils simultaneously with the simple requirement of controlling and monitoring helium vapor flow, and has a heat load of about 0.762 L/h in terms of LHe consumption.

Thermal Performance of Cryogenic Piping Multilayer Insulation in Actual Field Installations

NASA Technical Reports Server (NTRS)

Fesmire, J.; Augustnynowicz, S.; Thompson, K. (Technical Monitor)

2002-01-01

A standardized way of comparing the thermal performance of different pipelines in different sizes is needed. Vendor data for vacuum-insulated piping are typically given in heat leak rate per unit length (W/m) for a specific diameter pipeline. An overall k-value for actual field installations (k(sub oafi)) is therefore proposed as a more generalized measure for thermal performance comparison and design calculation. The k(sub oafi) provides a direct correspondence to the k-values reported for insulation materials and illustrates the large difference between ideal multilayer insulation (MLI) and actual MLI performance. In this experimental research study, a section of insulated piping was tested under cryogenic vacuum conditions, including simulated spacers and bending. Several different insulation systems were tested using a 1-meter-long cylindrical cryostat test apparatus. The simulated spacers tests showed significant degradation in the thermal performance of a given insulation system. An 18-meter-long pipeline test apparatus is now in operation at the Cryogenics Test Laboratory, NASA Kennedy Space Center, for conducting liquid nitrogen thermal performance tests.

Use of aromatherapy to promote a therapeutic nurse environment.

PubMed

Johnson, Kari; West, Toni; Diana, Shelly; Todd, Jodi; Haynes, Brianna; Bernhardt, Judy; Johnson, Roberta

2017-06-01

Workplace stress can affect nurse satisfaction. Aroma therapy as a therapeutic use of essential oil can be beneficial in reducing stress. Assess perceived stress pre-post introduction of Essential Oil Lavender among registered nurses, charge nurses, and patient care technicians in a trauma intensive care unit, surgical specialty care unit and an orthopedic trauma unit. Pre-post intervention with a quasi-experimental design. After a pre-survey, Essential Oil Lavender was diffused 24h per day over 30days in a designated nursing area that all nurses were not required to enter on each unit. Dependent sample t-test for "how often do nurses feel stressed a work in a typical week" revealed pre-survey mean 2.97 (SD=0.99) which was significantly higher than post-survey mean 2.70 (SD=0.92) with significance, t(69)=2.36, p=0.021, suggesting a difference in how often staff felt stressed at work in a typical week, trending down from "feeling stressed half of time" to "once in a while". There were no statistically significant differences in pre-post survey scores for TICU, TOU, or SSC as separate units. Use of essential oils to decrease work-related stress among nursing staff may improve retention, workplace environment, and increase nurse satisfaction. Copyright © 2017 Elsevier Ltd. All rights reserved.

A pilot study on using chlorine dioxide gas for disinfection of gastrointestinal endoscopes* #

PubMed Central

Yi, Ying; Hao, Li-mei; Ma, Shu-ren; Wu, Jin-hui; Wang, Tao; Lin, Song; Zhang, Zong-xing; Qi, Jian-cheng

2016-01-01

Objectives: This pilot study of employing chlorine dioxide (CD) gas to disinfect gastrointestinal endoscopes was conducted to meet the expectations of many endoscopy units in China for a high-efficiency and low-cost disinfectant. Methods: An experimental prototype with an active circulation mode was designed to use CD gas to disinfect gastrointestinal endoscopes. One type of testing device composed of polytetrafluoroethylene (PTFE) tubes (2 m long, inner diameter 1 mm) and bacterial carrier containers was used to simulate the channel of the endoscope. PTFE bacterial carriers inoculated with Bacillus atrophaeus with or without organic burden were used to evaluate the sporicidal activity of CD gas. Factors including exposure dosage, relative humidity (RH), and flow rate (FR) influencing the disinfection effect of CD gas were investigated. Moreover, an autoptic disinfecting test on eight real gastrointestinal endoscopes after clinical use was performed using the experimental prototype. Results: RH, exposure dosage, organic burden, and the FR through the channel significantly (P<0.05) affected the disinfection efficacy of CD gas for a long and narrow lumen. The log reduction increased as FR decreased. Treatment with 4 mg/L CD gas for 30 min at 0.8 L/min FR and 75% RH, resulted in complete inactivation of spores. Furthermore, all eight endoscopes with a maximum colony-forming unit of 915 were completely disinfected. The cost was only 3 CNY (0.46 USD) for each endoscope. Conclusions: The methods and results reported in this study could provide a basis for further studies on using CD gas for the disinfection of endoscopes. PMID:27381729

Distinguishing familiarity from fluency for the compound word pair effect in associative recognition.

PubMed

Ahmad, Fahad N; Hockley, William E

2017-09-01

We examined whether processing fluency contributes to associative recognition of unitized pre-experimental associations. In Experiments 1A and 1B, we minimized perceptual fluency by presenting each word of pairs on separate screens at both study and test, yet the compound word (CW) effect (i.e., hit and false-alarm rates greater for CW pairs with no difference in discrimination) did not reduce. In Experiments 2A and 2B, conceptual fluency was examined by comparing transparent (e.g., hand bag) and opaque (e.g., rag time) CW pairs in lexical decision and associative recognition tasks. Lexical decision was faster for transparent CWs (Experiment 2A) but in associative recognition, the CW effect did not differ by CW pair type (Experiment 2B). In Experiments 3A and 3B, we examined whether priming that increases processing fluency would influence the CW effect. In Experiment 3A, CW and non-compound word pairs were preceded with matched and mismatched primes at test in an associative recognition task. In Experiment 3B, only transparent and opaque CW pairs were presented. Results showed that presenting matched versus mismatched primes at test did not influence the CW effect. The CW effect in yes-no associative recognition is due to reliance on enhanced familiarity of unitized CW pairs.

Carbon capture test unit design and development using amine-based solid sorbent

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

Breault, Ronald W.; Spenik, James L.; Shadle, Lawrence J.

This study presents the design and development of a reactor system and the subsequent modifications to evaluate an integrated process to scrub carbon dioxide (CO 2) from synthetic flue gas using amine based solid sorbents. The paper presents the initial system design and then discusses the various changes implemented to address the change in sorbent from a 180 μm Geldart group B material to a 115 μm Geldart group A material as well as issues discovered during experimental trials where the major obstacle in system operation was the ability to maintain a constant circulation of a solid sorbent stemming frommore » this change in sorbent material. The system primarily consisted of four fluid beds, through which an amine impregnated solid sorbent was circulated and adsorption, pre-heat, regeneration, and cooling processes occurred. Instrumentation was assembled to characterize thermal, hydrodynamic, and gas adsorption performance in this integrated unit. A series of shakedown tests were performed and the configuration altered to meet the needs of the sorbent performance and achieve desired target capture efficiencies. Finally, methods were identified, tested, and applied to continuously monitor critical operating parameters including solids circulation rate, adsorbed and desorbed CO 2, solids inventories, and pressures.« less

78 FR 51678 - Market Tests of Experimental Postal Products

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-21

...] Market Tests of Experimental Postal Products AGENCY: Postal Regulatory Commission. ACTION: Proposed rule... tests of experimental products. The proposed rules address the contents of market test filings, describe... Tests I. Introduction The Commission proposes to establish rules governing market tests of experimental...

Contractor's STTR Phase I Final Report- Experimental Analysis and Model Development of Pyrolysis/Combustion of Coal/Biomass in a Bench Scale Spouted Bed Reactor

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

Baird, Benjamin; Loebick, Codruta; Roychoudhury, Subir

During Phase I both experimental evaluation and computational validation of an advanced Spouted Bed Reactor (SBR) approach for biomass and coal combustion was completed. All Phase I objectives were met and some exceeded. Comprehensive insight on SBR operation was achieved via design, fabrication, and testing of a small demonstration unit with pulverized coal and biomass as feedstock at University of Connecticut (UCONN). A scale-up and optimization tool for the next generation of coal and biomass co-firing for reducing GHG emissions was also developed. The predictive model was implemented with DOE’s MFIX computational model and was observed to accurately mimic evenmore » unsteady behavior. An updated Spouted Bed Reactor was fabricated, based on model feedback, and experimentally displayed near ideal behavior. This predictive capability based upon first principles and experimental correlation allows realistic simulation of mixed fuel combustion in these newly proposed power boiler designs. Compared to a conventional fluidized bed the SBR facilitates good mixing of coal and biomass, with relative insensitivity to particle size and densities, resulting in improved combustion efficiency. Experimental data with mixed coal and biomass fuels demonstrated complete oxidation at temperatures as low as 500ºC. This avoids NOx formation and residual carbon in the waste ash. Operation at stoichiometric conditions without requiring cooling or sintering of the carrier was also observed. Oxygen-blown operation were tested and indicated good performance. This highlighted the possibility of operating the SBR at a wide range of conditions suitable for power generation and partial oxidation byproducts. It also supports the possibility of implementing chemical looping (for readily capturing CO 2 and SO x).« less

Experimental Analysis and Model Development of Pyrolysis/Combustion of Coal/Biomass in a Bench Scale Spouted Bed Reactor.

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

Baird, Benjamin; Loebick, Codruta; Roychoudhury, Subir

During Phase I both experimental evaluation and computational validation of an advanced Spouted Bed Reactor (SBR) approach for biomass and coal combustion was completed. All Phase I objectives were met and some exceeded. Comprehensive insight on SBR operation was achieved via design, fabrication, and testing of a small demonstration unit with pulverized coal and biomass as feedstock at University of Connecticut (UCONN). A scale-up and optimization tool for the next generation of coal and biomass co-firing for reducing GHG emissions was also developed. The predictive model was implemented with DOE’s MFIX computational model and was observed to accurately mimic evenmore » unsteady behavior. An updated Spouted Bed Reactor was fabricated, based on model feedback, and experimentally displayed near ideal behavior. This predictive capability based upon first principles and experimental correlation allows realistic simulation of mixed fuel combustion in these newly proposed power boiler designs. Compared to a conventional fluidized bed the SBR facilitates good mixing of coal and biomass, with relative insensitivity to particle size and densities, resulting in improved combustion efficiency. Experimental data with mixed coal and biomass fuels demonstrated complete oxidation at temperatures as low as 500C. This avoids NOx formation and residual carbon in the waste ash. Operation at stoichiometric conditions without requiring cooling or sintering of the carrier was also observed. Oxygen-blown operation were tested and indicated good performance. This highlighted the possibility of operating the SBR at a wide range of conditions suitable for power generation and partial oxidation byproducts. It also supports the possibility of implementing chemical looping (for readily capturing CO2 and SOx).« less

Theory, design, and experimental verification of a reflectionless bianisotropic Huygens' metasurface for wide-angle refraction

NASA Astrophysics Data System (ADS)

Chen, Michael; Abdo-Sánchez, Elena; Epstein, Ariel; Eleftheriades, George V.

2018-03-01

Huygens' metasurfaces are electrically thin devices which allow arbitrary field transformations. Beam refraction is among the first demonstrations of realized metasurfaces. As previously shown for extreme-angle refraction, control over only the electric impedance and magnetic admittance of the Huygens' metasurface proved insufficient to produce the desired reflectionless field transformation. To maintain zero reflections for wide refraction angles, magnetoelectric coupling between the electric and magnetic response of the metasurface, leading to bianisotropy, can be introduced. In this paper, we report the theory, design, and experimental characterization of a reflectionless bianisotropic metasurface for extreme-angle refraction of a normally incident plane wave towards 71.8° at 20 GHz. The theory and design of three-layer asymmetric bianisotropic unit cells are discussed. The realized printed circuit board structure was tested via full-wave simulations as well as experimental characterization. To experimentally verify the prototype, two setups were used. A quasi-optical experiment was conducted to assess the specular reflections of the metasurface, while a far-field antenna measurement characterized its refraction nature. The measurements verify that the fabricated metasurface has negligible reflections and the majority of the scattered power is refracted to the desired Floquet mode. This provides an experimental demonstration of a reflectionless wide-angle refracting metasurface using a bianisotropic Huygens' metasurface at microwave frequencies.

Electrifying Engagement in Middle School Science Class: Improving Student Interest Through E-textiles

NASA Astrophysics Data System (ADS)

Tofel-Grehl, Colby; Fields, Deborah; Searle, Kristin; Maahs-Fladung, Cathy; Feldon, David; Gu, Grace; Sun, Chongning

2017-08-01

Most interventions with "maker" technologies take place outside of school or out of core area classrooms. However, intervening in schools holds potential for reaching much larger numbers of students and the opportunity to shift instructional dynamics in classrooms. This paper shares one such intervention where electronic textiles (sewable circuits) were introduced into eighth grade science classes with the intent of exploring possible gains in student learning and motivation, particularly for underrepresented minorities. Using a quasi-experimental design, four classes engaged in a traditional circuitry unit while the other four classes undertook a new e-textile unit. Overall, students in both groups demonstrated significant learning gains on standard test items without significant differences between conditions. Significant differences appeared between groups' attitudes toward science after the units in ways that show increasing interest in science by students in the e-textile unit. In particular, they reported positive identity shifts pertaining to their perceptions of the beliefs of their friends, family, and teacher. Findings and prior research suggest that student-created e-textile designs provide opportunities for connections outside of the classroom with friends and family and may shift students' perceptions of their teacher's beliefs about them more positively.

Effect of 0.2% chlorhexidine on microbial and fungal contamination of dental unit waterlines

PubMed Central

Agahi, Raha Habib; Hashemipour, Maryam Alsadat; Kalantari, Mahsa; Ayatollah-Mosavi, Amin; Aghassi, Hossein; Nassab, Amir Hossein Gandjalikhan

2014-01-01

Background: It is known that dental unit waterline can be a source of infection. The aim of this study was to evaluate the efficacy of a mouthwash, chlorhexidine, in controlling microbial and fungal contamination of dental unit waterlines. Materials and Methods: In the present experimental study, the water in high-speed handpieces and air/water syringes of 35 dental units in a dental school was investigated microbiologically. Five of the units and one tap water served as controls; 100-200-mL water samples were collected aseptically in sterile containers in the morning after a 2-min purge. Water reservoir bottles were emptied and 50 mL of 0.2% chlorhexidine mouthwash was introduced into the tank. Then the water syringe was used to flush the waterline until the pink-colored chlorhexidine was observed to flow from the water syringe. Before the next day's session and before the students used the unit, two water samples from the water syringe and water turbine was collected. The samples were transferred to the laboratory. After 48 h at 37°C, the microbial colonies were counted. The number of these colonies was evaluated using colony forming unit CFU. Data were analyzed with Mann — Whitney U test and SPSS 13.5 statistical program. The statistical significance was defined at P ≤ 0.05. Results: All 35 units were contaminated before chlorhexidine use; no contamination was detected after adding chlorhexidine to the waterlines of the units. After week 1, 28 of the 30 treated dental unit waterlines (DUWLs) had values of CFU/mL less than 200. Conclusion: The present study showed that the use of chlorhexidine could reduce microbial counts in dental unit waterlines. PMID:25097645

Effect of 0.2% chlorhexidine on microbial and fungal contamination of dental unit waterlines.

PubMed

Agahi, Raha Habib; Hashemipour, Maryam Alsadat; Kalantari, Mahsa; Ayatollah-Mosavi, Amin; Aghassi, Hossein; Nassab, Amir Hossein Gandjalikhan

2014-05-01

It is known that dental unit waterline can be a source of infection. The aim of this study was to evaluate the efficacy of a mouthwash, chlorhexidine, in controlling microbial and fungal contamination of dental unit waterlines. In the present experimental study, the water in high-speed handpieces and air/water syringes of 35 dental units in a dental school was investigated microbiologically. Five of the units and one tap water served as controls; 100-200-mL water samples were collected aseptically in sterile containers in the morning after a 2-min purge. Water reservoir bottles were emptied and 50 mL of 0.2% chlorhexidine mouthwash was introduced into the tank. Then the water syringe was used to flush the waterline until the pink-colored chlorhexidine was observed to flow from the water syringe. Before the next day's session and before the students used the unit, two water samples from the water syringe and water turbine was collected. The samples were transferred to the laboratory. After 48 h at 37°C, the microbial colonies were counted. The number of these colonies was evaluated using colony forming unit CFU. Data were analyzed with Mann - Whitney U test and SPSS 13.5 statistical program. The statistical significance was defined at P ≤ 0.05. All 35 units were contaminated before chlorhexidine use; no contamination was detected after adding chlorhexidine to the waterlines of the units. After week 1, 28 of the 30 treated dental unit waterlines (DUWLs) had values of CFU/mL less than 200. The present study showed that the use of chlorhexidine could reduce microbial counts in dental unit waterlines.

Effects of repeated anodal tDCS coupled with cognitive training for patients with severe traumatic brain injury: a pilot randomized controlled trial.

PubMed

Leśniak, Marcin; Polanowska, Katarzyna; Seniów, Joanna; Członkowska, Anna

2014-01-01

To determine whether cumulative anodal transcranial direct current stimulation (A-tDCS) of the left dorsolateral prefrontal cortex (DLPFC) could enhance rehabilitation of memory and attention in patients with traumatic brain injury (TBI). Inpatient and outpatient neurorehabilitation unit. Twenty-three adult patients, 4- to 92- months post severe TBI. Participants were randomly allocated to 2 groups. The experimental group received A-tDCS (10 minutes; 1 mA; in the DLPFC), followed by rehabilitative cognitive training, daily for 15 days. Controls received A-tDCS for 25 seconds (sham condition) with the same rehabilitation. Battery of memory and attention tests, which included visual and auditory modalities. Participants were tested twice before beginning rehabilitation (to control for spontaneous recovery), after rehabilitation completion, and 4 months later. Tests scores in both groups were similar at 3 weeks before and immediately before treatment. After treatment, the experimental group exhibited larger effect sizes in 6 of 8 cognitive outcome measures, but they were not significantly different from controls. At follow-up, differences remained insignificant. In contrast to previous studies, our study did not provide sufficient evidence to support the efficacy of repeated A-tDCS for enhancing rehabilitation of memory and attention in patients after severe TBI.

Variation: Use It or Misuse It--Replication and Its Variants

ERIC Educational Resources Information Center

Drummond, Gordon B.; Vowler, Sarah L.

2012-01-01

In this article, the authors talk about variation and how variation between measurements may be reduced if sampling is not random. They also talk about replication and its variants. A replicate is a repeated measurement from the same experimental unit. An experimental unit is the smallest part of an experiment or a study that can be subject to a…

Me and My Environment, Unit V: Air and Water in My Environment, Experimental Edition 1973-74.

ERIC Educational Resources Information Center

Biological Sciences Curriculum Study, Boulder, CO.

The experimental 1973-74 edition of Unit V consists of 35 life science curriculum activities intended for 13- to 16-year-old educable mentally handicapped adolescents. The role of the teacher in continuing field trials is noted and environmental themes and elements, inquiry skills, problem solving skills, and applicational behaviors and attitudes…

Boise Basin Experimental Forest (Idaho)

Treesearch

Russell T. Graham; Theresa B. Jain

2004-01-01

The Boise Basin Experimental Forest was established in 1933 to study ponderosa pine. It consists of 3,537 ha with elevations ranging from 1,200 to 3,630 m. Boise Basin is divided into three units surrounding Idaho City in southern Idaho. Idaho City was a booming mining town in the 1870s and the surrounding forests supplied material to the community. Two units were...

Gender and Racial Differences: Development of Sixth Grade Students' Geometric Spatial Visualization within an Earth/Space Unit

ERIC Educational Resources Information Center

Jackson, Christa; Wilhelm, Jennifer Anne; Lamar, Mary; Cole, Merryn

2015-01-01

This study investigated sixth-grade middle-level students' geometric spatial development by gender and race within and between control and experimental groups at two middle schools as they participated in an Earth/Space unit. The control group utilized a regular Earth/Space curriculum and the experimental group used a National Aeronautics and…

Me and My Environment, Unit IV: Transfer and Cycling of Materials in My Environment, Experimental Edition 1973-74.

ERIC Educational Resources Information Center

Biological Sciences Curriculum Study, Boulder, CO.

The experimental 1973-74 edition of Unit IV consists of 28 life science curriculum activities for 13- to 16-year-old educable mentally handicapped children. The role of the teacher in continuing field trials is noted and environmental themes and elements, inquiry skills, problem solving skills, and applicational behaviors and attitudes are…

Feasibility study on phyto-remediation techniques for soil contaminated by the Fukushima Dai-Ichi nuclear power plant accident

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

Yuu Ishimori; Akihiro Sakoda; Mina Yamada

2013-07-01

Tottori University and the Japan Atomic Energy Agency carried out jointly the feasibility study on phyto-remediation techniques, which apply to soil contaminated by the TEPCO's Fukushima Dai-ichi NPP accident. This paper illustrates the results from experimental investigations. Experimental investigations include both water-culture tests and field tests. Several plants, mainly halophytes that can specifically absorb more Na than K, and others like sunflower demonstrated for other domestic large-scale tests, were water-cultured and examined for screening. Easily cultivated and harvested plants without harmful effects on subsequent cultivation were also considered. New Zealand spinach was selected as a candidate for demonstrations in fields.more » The field tests were carried out at two sites of different agricultural types in Minami-soma, Fukushima prefecture. Concentration of {sup 137}Cs in soil is about 4.5 Bq/g-dry as the average of 10 cm depth. The aims of the field tests are to confirm absorption ability and environmental adaptation of the test plants and to document the cost and performance of projects. In conclusion, the absorption of {sup 137}Cs activity per unit area (Bq/m{sup 2}) by New Zealand spinach could be approximately 0.5%. To achieve an effective result in removal of {sup 137}Cs from soil in around a decade, it is required to find the plant which has ten or more times higher absorption capacity than New Zealand spinach. From the consistency of both results in water-culture and field tests, the water-culture test can be valid for screening. In addition, applicable sites will be limited to fields which are too steep or too narrow to use mechanical diggers, and which are free from any restrictions to enter. (authors)« less

Mechanical behavior of regular open-cell porous biomaterials made of diamond lattice unit cells.

PubMed

Ahmadi, S M; Campoli, G; Amin Yavari, S; Sajadi, B; Wauthle, R; Schrooten, J; Weinans, H; Zadpoor, A A

2014-06-01

Cellular structures with highly controlled micro-architectures are promising materials for orthopedic applications that require bone-substituting biomaterials or implants. The availability of additive manufacturing techniques has enabled manufacturing of biomaterials made of one or multiple types of unit cells. The diamond lattice unit cell is one of the relatively new types of unit cells that are used in manufacturing of regular porous biomaterials. As opposed to many other types of unit cells, there is currently no analytical solution that could be used for prediction of the mechanical properties of cellular structures made of the diamond lattice unit cells. In this paper, we present new analytical solutions and closed-form relationships for predicting the elastic modulus, Poisson׳s ratio, critical buckling load, and yield (plateau) stress of cellular structures made of the diamond lattice unit cell. The mechanical properties predicted using the analytical solutions are compared with those obtained using finite element models. A number of solid and porous titanium (Ti6Al4V) specimens were manufactured using selective laser melting. A series of experiments were then performed to determine the mechanical properties of the matrix material and cellular structures. The experimentally measured mechanical properties were compared with those obtained using analytical solutions and finite element (FE) models. It has been shown that, for small apparent density values, the mechanical properties obtained using analytical and numerical solutions are in agreement with each other and with experimental observations. The properties estimated using an analytical solution based on the Euler-Bernoulli theory markedly deviated from experimental results for large apparent density values. The mechanical properties estimated using FE models and another analytical solution based on the Timoshenko beam theory better matched the experimental observations. Copyright © 2014 Elsevier Ltd. All rights reserved.

Sequential Pumping and Tracing Experiments Using Packer Systems in a Chalk Aquifer

NASA Astrophysics Data System (ADS)

Goderniaux, P.; Poulain, A.

2016-12-01

The hydraulic characterization of subsurface geological unit is crucial for many hydrogeological applications. The quantification and the spatial distribution of the related parameters is however not always straightforward. As a consequence, parameters values are often considered as homogeneous over the thickness of an aquifer unit. To try to catch the possible heterogeneity, sequential tracer and pumping tests have been performed between two piezometers, using inflatable packer systems to isolate and study specific sections of the boreholes. The experimental site is composed of two 50m-deep piezometers located in a chalk aquifer, in South-West Belgium. The boreholes are not equipped with any casing or screen, to allow the use of the packers. The chalk is characterized by a high porosity, which enables the storage of large quantities of groundwater, and by fractures where fast preferential flow occurs. Recordings made with a borehole camera system has evidenced the presence of many fractures along the borehole, with a mean density of 2 fractures by meter. The frequency of fracture occurrences is however variable along the borehole. Pumping and tracer tests have been performed (1) using the whole borehole depth, and (2) over specific 1-meter sections, isolated with packers. Results confirm that flow and transport parameters are heterogeneous within the chalk aquifer unit. Groundwater head variations, induced by water pumping or injection, and tracer transfer times are variable according to the studied borehole section. Tests are still going on, and the objective is to have measurements over the whole borehole, to be used for numerical interpretation.

Experimentally valid predictions of muscle force and EMG in models of motor-unit function are most sensitive to neural properties.

PubMed

Keenan, Kevin G; Valero-Cuevas, Francisco J

2007-09-01

Computational models of motor-unit populations are the objective implementations of the hypothesized mechanisms by which neural and muscle properties give rise to electromyograms (EMGs) and force. However, the variability/uncertainty of the parameters used in these models--and how they affect predictions--confounds assessing these hypothesized mechanisms. We perform a large-scale computational sensitivity analysis on the state-of-the-art computational model of surface EMG, force, and force variability by combining a comprehensive review of published experimental data with Monte Carlo simulations. To exhaustively explore model performance and robustness, we ran numerous iterative simulations each using a random set of values for nine commonly measured motor neuron and muscle parameters. Parameter values were sampled across their reported experimental ranges. Convergence after 439 simulations found that only 3 simulations met our two fitness criteria: approximating the well-established experimental relations for the scaling of EMG amplitude and force variability with mean force. An additional 424 simulations preferentially sampling the neighborhood of those 3 valid simulations converged to reveal 65 additional sets of parameter values for which the model predictions approximate the experimentally known relations. We find the model is not sensitive to muscle properties but very sensitive to several motor neuron properties--especially peak discharge rates and recruitment ranges. Therefore to advance our understanding of EMG and muscle force, it is critical to evaluate the hypothesized neural mechanisms as implemented in today's state-of-the-art models of motor unit function. We discuss experimental and analytical avenues to do so as well as new features that may be added in future implementations of motor-unit models to improve their experimental validity.