14 CFR 25.939 - Turbine engine operating characteristics.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Turbine engine operating characteristics... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.939 Turbine engine operating characteristics. (a) Turbine engine operating characteristics must be investigated in...

14 CFR 25.939 - Turbine engine operating characteristics.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Turbine engine operating characteristics... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.939 Turbine engine operating characteristics. (a) Turbine engine operating characteristics must be investigated in...

14 CFR 25.939 - Turbine engine operating characteristics.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Turbine engine operating characteristics... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.939 Turbine engine operating characteristics. (a) Turbine engine operating characteristics must be investigated in...

14 CFR 25.939 - Turbine engine operating characteristics.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Turbine engine operating characteristics... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.939 Turbine engine operating characteristics. (a) Turbine engine operating characteristics must be investigated in...

14 CFR 25.939 - Turbine engine operating characteristics.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Turbine engine operating characteristics... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.939 Turbine engine operating characteristics. (a) Turbine engine operating characteristics must be investigated in...

Confidence intervals for differences between volumes under receiver operating characteristic surfaces (VUS) and generalized Youden indices (GYIs).

PubMed

Yin, Jingjing; Nakas, Christos T; Tian, Lili; Reiser, Benjamin

2018-03-01

This article explores both existing and new methods for the construction of confidence intervals for differences of indices of diagnostic accuracy of competing pairs of biomarkers in three-class classification problems and fills the methodological gaps for both parametric and non-parametric approaches in the receiver operating characteristic surface framework. The most widely used such indices are the volume under the receiver operating characteristic surface and the generalized Youden index. We describe implementation of all methods and offer insight regarding the appropriateness of their use through a large simulation study with different distributional and sample size scenarios. Methods are illustrated using data from the Alzheimer's Disease Neuroimaging Initiative study, where assessment of cognitive function naturally results in a three-class classification setting.

Adolescent bariatric surgery program characteristics: the Teen Longitudinal Assessment of Bariatric Surgery (Teen-LABS) study experience.

PubMed

Michalsky, Marc P; Inge, Thomas H; Teich, Steven; Eneli, Ihuoma; Miller, Rosemary; Brandt, Mary L; Helmrath, Michael; Harmon, Carroll M; Zeller, Meg H; Jenkins, Todd M; Courcoulas, Anita; Buncher, Ralph C

2014-02-01

The number of adolescents undergoing weight loss surgery (WLS) has increased in response to the increasing prevalence of severe childhood obesity. Adolescents undergoing WLS require unique support, which may differ from adult programs. The aim of this study was to describe institutional and programmatic characteristics of centers participating in Teen Longitudinal Assessment of Bariatric Surgery (Teen-LABS), a prospective study investigating safety and efficacy of adolescent WLS. Data were obtained from the Teen-LABS database, and site survey completed by Teen-LABS investigators. The survey queried (1) institutional characteristics, (2) multidisciplinary team composition, (3) clinical program characteristics, and (4) clinical research infrastructure. All centers had extensive multidisciplinary involvement in the assessment, pre-operative education, and post-operative management of adolescents undergoing WLS. Eligibility criteria and pre-operative clinical and diagnostic evaluations were similar between programs. All programs have well-developed clinical research infrastructure, use adolescent-specific educational resources, and maintain specialty equipment, including high weight capacity diagnostic imaging equipment. The composition of clinical team and institutional resources is consistent with current clinical practice guidelines. These characteristics, coupled with dedicated research staff, have facilitated enrollment of 242 participants into Teen-LABS. © 2013 Published by Elsevier Inc.

Case-Mix Variables and Predictors for Outcomes of Laparoscopic Hysterectomy: A Systematic Review.

PubMed

Driessen, Sara R C; Sandberg, Evelien M; la Chapelle, Claire F; Twijnstra, Andries R H; Rhemrev, Johann P T; Jansen, Frank Willem

2016-01-01

The assessment of surgical quality is complex, and an adequate case-mix correction is missing in currently applied quality indicators. The purpose of this study is to give an overview of all studies mentioning statistically significant associations between patient characteristics and surgical outcomes for laparoscopic hysterectomy (LH). Additionally, we identified a set of potential case-mix characteristics for LH. This systematic review was conducted according to the Meta-Analysis of Observational Studies in Epidemiology guidelines. We searched PubMed and EMBASE from January 1, 2000 to August 1, 2015. All articles describing statistically significant associations between patient characteristics and adverse outcomes of LH for benign indications were included. Primary outcomes were blood loss, operative time, conversion, and complications. The methodologic quality of the included studies was assessed using the Newcastle-Ottawa Quality Assessment Scale. The included articles were summed per predictor and surgical outcome. Three sets of case-mix characteristics were determined, stratified by different levels of evidence. Eighty-five of 1549 identified studies were considered eligible. Uterine weight and body mass index (BMI) were the most mentioned predictors (described, respectively, 83 and 45 times) in high quality studies. For longer operative time and higher blood loss, uterine weight ≥ 250 to 300 g and ≥500 g and BMI ≥ 30 kg/m(2) dominated as predictors. Previous operations, adhesions, and higher age were also considered as predictors for longer operative time. For complications and conversions, the patient characteristics varied widely, and uterine weight, BMI, previous operations, adhesions, and age predominated. Studies of high methodologic quality indicated uterine weight and BMI as relevant case-mix characteristics for all surgical outcomes. For future development of quality indicators of LH and to compare surgical outcomes adequately, a case-mix correction is suggested for at least uterine weight and BMI. A potential case-mix correction for adhesions and previous operations can be considered. For both surgeons and patients it is valuable to be aware of potential factors predicting adverse outcomes and to anticipate this. Finally, to benchmark clinical outcomes at an international level, it is of the utmost importance to introduce uniform outcome definitions. Copyright © 2016 AAGL. Published by Elsevier Inc. All rights reserved.

Analysis of operational requirements for medium density air transportation. Volume 1: Summary

NASA Technical Reports Server (NTRS)

1975-01-01

The medium density air travel market was studied to determine the aircraft design and operational requirements. The impact of operational characteristics on the air travel system and the economic viability of the study aircraft were also evaluated. Medium density is defined in terms of numbers of people transported (20 to 500 passengers per day on round trip routes), and frequency of service ( a minumium of two and maximum of eight round trips per day) for 10 regional carriers. The operational characteristics of aircraft best suited to serve the medium density air transportation market are determined and a basepoint aircraft is designed from which tradeoff studies and parametric variations could be conducted. The impact of selected aircraft on the medium density market, economics, and operations is ascertained. Research and technology objectives for future programs in medium density air transportation are identified and ranked.

14 CFR 27.939 - Turbine engine operating characteristics.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Turbine engine operating characteristics....939 Turbine engine operating characteristics. (a) Turbine engine operating characteristics must be... limitations of the rotorcraft and of the engine. (b) The turbine engine air inlet system may not, as a result...

14 CFR 27.939 - Turbine engine operating characteristics.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Turbine engine operating characteristics....939 Turbine engine operating characteristics. (a) Turbine engine operating characteristics must be... limitations of the rotorcraft and of the engine. (b) The turbine engine air inlet system may not, as a result...

14 CFR 27.939 - Turbine engine operating characteristics.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Turbine engine operating characteristics....939 Turbine engine operating characteristics. (a) Turbine engine operating characteristics must be... limitations of the rotorcraft and of the engine. (b) The turbine engine air inlet system may not, as a result...

14 CFR 29.939 - Turbine engine operating characteristics.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Turbine engine operating characteristics....939 Turbine engine operating characteristics. (a) Turbine engine operating characteristics must be... limitations of the rotorcraft and of the engine. (b) The turbine engine air inlet system may not, as a result...

14 CFR 29.939 - Turbine engine operating characteristics.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Turbine engine operating characteristics....939 Turbine engine operating characteristics. (a) Turbine engine operating characteristics must be... limitations of the rotorcraft and of the engine. (b) The turbine engine air inlet system may not, as a result...

14 CFR 29.939 - Turbine engine operating characteristics.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Turbine engine operating characteristics....939 Turbine engine operating characteristics. (a) Turbine engine operating characteristics must be... limitations of the rotorcraft and of the engine. (b) The turbine engine air inlet system may not, as a result...

14 CFR 29.939 - Turbine engine operating characteristics.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Turbine engine operating characteristics....939 Turbine engine operating characteristics. (a) Turbine engine operating characteristics must be... limitations of the rotorcraft and of the engine. (b) The turbine engine air inlet system may not, as a result...

14 CFR 27.939 - Turbine engine operating characteristics.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Turbine engine operating characteristics....939 Turbine engine operating characteristics. (a) Turbine engine operating characteristics must be... limitations of the rotorcraft and of the engine. (b) The turbine engine air inlet system may not, as a result...

14 CFR 27.939 - Turbine engine operating characteristics.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Turbine engine operating characteristics....939 Turbine engine operating characteristics. (a) Turbine engine operating characteristics must be... limitations of the rotorcraft and of the engine. (b) The turbine engine air inlet system may not, as a result...

14 CFR 29.939 - Turbine engine operating characteristics.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Turbine engine operating characteristics....939 Turbine engine operating characteristics. (a) Turbine engine operating characteristics must be... limitations of the rotorcraft and of the engine. (b) The turbine engine air inlet system may not, as a result...

The Obsessive Compulsive Scale of the Child Behavior Checklist Predicts Obsessive-Compulsive Disorder: A Receiver Operating Characteristic Curve Analysis

ERIC Educational Resources Information Center

Hudziak, James J.; Althoff, Robert R.; Stanger, Catherine; van Beijsterveldt, C. E. M.; Nelson, Elliot C.; Hanna, Gregory L.; Boomsma, Dorret I.; Todd, Richard D.

2006-01-01

Background: The purpose of this study was to determine a score on the Obsessive Compulsive Scale (OCS) from the Child Behavior Checklist (CBCL) to screen for obsessive compulsive disorder (OCD) in children and to rigorously test the specificity and sensitivity of a single cutpoint. Methods: A receiver operating characteristic (ROC) curve analysis…

Attitude control of an orbiting space vehicle.

NASA Technical Reports Server (NTRS)

Sutherlin, D. W.; Boland, J. S. , III; Borelli, M. T.

1971-01-01

Study of the normal and clamped modes of operation and dynamic response characteristics of the gimbaled control moment gyro (CMG) designed to fulfill the stringent pointing requirements of the Skylab telescope mount when the spacecraft is under the influence of both external and internal torques. The results indicate that the clamped mode of operation provides a feasible approach for significantly improving the system characteristics.

Impact characteristics for high-pressure large-flow water-based emulsion pilot operated check valve reverse opening

NASA Astrophysics Data System (ADS)

Liu, Lei; Huang, Chuanhui; Yu, Ping; Zhang, Lei

2017-10-01

To improve the dynamic characteristics and cavitation characteristics of large-flow pilot operated check valve, consider the pilot poppet as the research object, analyses working principle and design three different kinds of pilot poppets. The vibration characteristics and impact characteristics are analyzed. The simulation model is established through flow field simulation software. The cavitation characteristics of large-flow pilot operated check valve are studied and discussed. On this basis, high-pressure large-flow impact experimental system is used for impact experiment, and the cavitation index is discussed. Then optimal structure is obtained. Simulation results indicate that the increase of pilot poppet half cone angle can effectively reduce the cavitation area, reducing the generation of cavitation. Experimental results show that the pressure impact is not decreasing with increasing of pilot poppet half cone angle in process of unloading, but the unloading capacity, response speed and pilot poppet half cone angle are positively correlated. The impact characteristics of 60° pilot poppet, and its cavitation index is lesser, which indicates 60° pilot poppet is the optimal structure, with the theory results are basically identical.

Analysis of Performance of Jet Engine from Characteristics of Components II : Interaction of Components as Determined from Engine Operation

NASA Technical Reports Server (NTRS)

Goldstein, Arthur W; Alpert, Sumner; Beede, William; Kovach, Karl

1949-01-01

In order to understand the operation and the interaction of jet-engine components during engine operation and to determine how component characteristics may be used to compute engine performance, a method to analyze and to estimate performance of such engines was devised and applied to the study of the characteristics of a research turbojet engine built for this investigation. An attempt was made to correlate turbine performance obtained from engine experiments with that obtained by the simpler procedure of separately calibrating the turbine with cold air as a driving fluid in order to investigate the applicability of component calibration. The system of analysis was also applied to prediction of the engine and component performance with assumed modifications of the burner and bearing characteristics, to prediction of component and engine operation during engine acceleration, and to estimates of the performance of the engine and the components when the exhaust gas was used to drive a power turbine.

49 CFR 234.205 - Operating characteristics of warning system apparatus.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Operating characteristics of warning system... Maintenance Standards § 234.205 Operating characteristics of warning system apparatus. Operating... system shall be maintained in accordance with the limits within which the system is designed to operate. ...

49 CFR 234.205 - Operating characteristics of warning system apparatus.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Operating characteristics of warning system... Maintenance Standards § 234.205 Operating characteristics of warning system apparatus. Operating... system shall be maintained in accordance with the limits within which the system is designed to operate. ...

49 CFR 234.205 - Operating characteristics of warning system apparatus.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Operating characteristics of warning system... Maintenance Standards § 234.205 Operating characteristics of warning system apparatus. Operating... system shall be maintained in accordance with the limits within which the system is designed to operate. ...

An evaluation of energy conservation measures utilized by public transit systems : a case study in Texas

DOT National Transportation Integrated Search

1995-07-01

The primary focus of this study was to emphasize transit system energy characteristics by examining the vehicle characteristics, right-of-way charactertistics and the operational aspects of the services. The objectives : of this study were to become ...

33 CFR 157.158 - COW operations: Changed characteristics.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false COW operations: Changed... CARRYING OIL IN BULK Crude Oil Washing (COW) System on Tank Vessels Cow Operations § 157.158 COW operations: Changed characteristics. The COW system may be operated with characteristics that do not meet those...

Experimental Study of Injection Characteristics of a Multi-hole port injector on various Fuel Injection pressures and Temperatures

NASA Astrophysics Data System (ADS)

Movahednejad, E.; Ommi, F.; Nekofar, K.

2013-04-01

The structures of the port injector spray dominates the mixture preparation process and strongly affect the subsequent engine combustion characteristics over a wide range of operating conditions in port-injection gasoline engines. All these spray characteristics are determined by particular injector design and operating conditions. In this paper, an experimental study is made to characterize the breakup mechanism and spray characteristics of a injector with multi-disc nozzle (SAGEM,D2159MA). A comparison was made on injection characteristics of the multi-hole injectors and its effects on various fuel pressure and temperature. The distributions of the droplet size and velocity and volume flux were characterized using phase Doppler anemometry (PDA) technique. Through this work, it was found that the injector produces a finer spray with a wide spray angle in higher fuel pressure and temperature.

Drive Control Scheme of Electric Power Assisted Wheelchair Based on Neural Network Learning of Human Wheelchair Operation Characteristics

NASA Astrophysics Data System (ADS)

Tanohata, Naoki; Seki, Hirokazu

This paper describes a novel drive control scheme of electric power assisted wheelchairs based on neural network learning of human wheelchair operation characteristics. “Electric power assisted wheelchair” which enhances the drive force of the operator by employing electric motors is expected to be widely used as a mobility support system for elderly and disabled people. However, some handicapped people with paralysis of the muscles of one side of the body cannot maneuver the wheelchair as desired because of the difference in the right and left input force. Therefore, this study proposes a neural network learning system of such human wheelchair operation characteristics and a drive control scheme with variable distribution and assistance ratios. Some driving experiments will be performed to confirm the effectiveness of the proposed control system.

Screening for Depressive Disorders Using the Mood and Anxiety Symptoms Questionnaire Anhedonic Depression Scale: A Receiver-Operating Characteristic Analysis

ERIC Educational Resources Information Center

Bredemeier, Keith; Spielberg, Jeffery M.; Silton, Rebecca Levin; Berenbaum, Howard; Heller, Wendy; Miller, Gregory A.

2010-01-01

The present study examined the utility of the anhedonic depression scale from the Mood and Anxiety Symptoms Questionnaire (MASQ-AD scale) as a way to screen for depressive disorders. Using receiver-operating characteristic analysis, we examined the sensitivity and specificity of the full 22-item MASQ-AD scale, as well as the 8- and 14-item…

Accuracy of micro powder dosing via a vibratory sieve-chute system.

PubMed

Besenhard, M O; Faulhammer, E; Fathollahi, S; Reif, G; Calzolari, V; Biserni, S; Ferrari, A; Lawrence, S M; Llusa, M; Khinast, J G

2015-08-01

This paper describes a powder dosing system with a vibratory sieve mounted on a chute that doses particles into a capsule. Vertical vibration occurred with a broad range of frequencies and amplitudes. During dosing events, the fill weight was accurately recorded via a capacitance sensor, covering the capsules and making it possible to analyze filling characteristics, that is, the fill rates and their robustness. The range of frequencies and amplitudes was screened for settings that facilitated reasonable (no blocking, no spilling) fill rates for three lactose powders. The filling characteristics were studied within this operating space. The results reveal similar operating spaces for all investigated powders. The fill rate robustness varied distinctly in the operating space, which is of prime importance for selecting the settings for continuous feeding applications. In addition, we present accurate dosing studies utilizing the knowledge about the filling characteristics of each powder. Copyright © 2015 Elsevier B.V. All rights reserved.

Considerations for Architecture Level Trade Studies for Environmental Sensors

NASA Technical Reports Server (NTRS)

Peterson, Craig

2010-01-01

Comparisons of key characteristics of environmental sensors such as technology readiness levels, mass, power, volume, and detection capabilities are essential for initial trade studies to determine likely candidates for further development and evaluation. However, these trade studies only provide part of the information necessary to make selection decisions. Ultimately, the sensors must be judged based on the overall system architectures and operational scenarios for which they are intended. This means that additional characteristics, such as architectural needs for redundancy, operational lifetime, ability to maintain calibration, and repair and replacement strategies, among others, must also be considered. Given that these characteristics can be extremely time-consuming and costly to obtain, careful planning is essential to minimize the effort involved. In this paper, an approach is explored for determining an effective yet comprehensive set of architecture level trades which is minimally impacted by the inevitable changes in operational (mission) scenarios. The approach will also identify and integrate the various facilities and opportunities required to obtain the desired architecture level trade information.

Feasibility study of modern airships, phase 1. Volume 3: Historical overview (task 1)

NASA Technical Reports Server (NTRS)

Faurote, G. L.

1975-01-01

The history of lighter-than-air vehicles is reviewed in terms of providing a background for the mission analysis and parametric analysis tasks. Data from past airships and airship operations are presented in the following areas: (1) parameterization of design characteristics; (2) markets, missions, costs, and operating procedures, (3) indices of efficiency for comparison; (4) identification of critical design and operational characteristics; and (5) definition of the 1930 state-of-the-art and the 1974 state-of-the-art from a technical and economic standpoint.

Planning for success: desired characteristics of special operations surgeons, a pilot study.

PubMed

Campbell, Barrett H; Alderman, Shawn M

2012-01-01

Selection criteria for Special Operations Forces (SOF) physicians are often unclear to potential candidates without prior SOF experience. To date, no published career resource exists to guide the careers of physicians interested in becoming a SOF surgeon. Using a survey tool, desirable characteristics and personal attributes were identified that can be used to inform candidate career decisions and better prepare them for a future position in Special Operations. A descriptive, cross-sectional survey instrument was developed and distributed to current Army SOF Command Surgeons for further distribution to subordinate surgeons. RESULTS were analyzed as a cohort and by subordinate command. Respondents consisted of current SOF Surgeons. Uniformly, the individual characteristics most strongly desired are professionalism, being a team player, and leadership. Possessing or obtaining Airborne and Flight Surgeon qualifications prior to consideration for a surgeon position was highly desired. Residency training within Family Medicine or Emergency Medicine constituted the vast majority of specialty preference. Understanding which characteristics and attributes are desirable to current surgeons and commanders can aid physicians interested in SOF surgeon positions. Using this study and future studies can guide career planning and foster the selection of ideally trained physicians who will operate at the tip of the spear. The views expressed are those of the author(s) and do not reflect the official policy of the Department of the Army, the Department of Defense or the U.S. Government. 2012.

Time and frequency domain characteristics of detrending-operation-based scaling analysis: Exact DFA and DMA frequency responses

NASA Astrophysics Data System (ADS)

Kiyono, Ken; Tsujimoto, Yutaka

2016-07-01

We develop a general framework to study the time and frequency domain characteristics of detrending-operation-based scaling analysis methods, such as detrended fluctuation analysis (DFA) and detrending moving average (DMA) analysis. In this framework, using either the time or frequency domain approach, the frequency responses of detrending operations are calculated analytically. Although the frequency domain approach based on conventional linear analysis techniques is only applicable to linear detrending operations, the time domain approach presented here is applicable to both linear and nonlinear detrending operations. Furthermore, using the relationship between the time and frequency domain representations of the frequency responses, the frequency domain characteristics of nonlinear detrending operations can be obtained. Based on the calculated frequency responses, it is possible to establish a direct connection between the root-mean-square deviation of the detrending-operation-based scaling analysis and the power spectrum for linear stochastic processes. Here, by applying our methods to DFA and DMA, including higher-order cases, exact frequency responses are calculated. In addition, we analytically investigate the cutoff frequencies of DFA and DMA detrending operations and show that these frequencies are not optimally adjusted to coincide with the corresponding time scale.

Time and frequency domain characteristics of detrending-operation-based scaling analysis: Exact DFA and DMA frequency responses.

PubMed

Kiyono, Ken; Tsujimoto, Yutaka

2016-07-01

We develop a general framework to study the time and frequency domain characteristics of detrending-operation-based scaling analysis methods, such as detrended fluctuation analysis (DFA) and detrending moving average (DMA) analysis. In this framework, using either the time or frequency domain approach, the frequency responses of detrending operations are calculated analytically. Although the frequency domain approach based on conventional linear analysis techniques is only applicable to linear detrending operations, the time domain approach presented here is applicable to both linear and nonlinear detrending operations. Furthermore, using the relationship between the time and frequency domain representations of the frequency responses, the frequency domain characteristics of nonlinear detrending operations can be obtained. Based on the calculated frequency responses, it is possible to establish a direct connection between the root-mean-square deviation of the detrending-operation-based scaling analysis and the power spectrum for linear stochastic processes. Here, by applying our methods to DFA and DMA, including higher-order cases, exact frequency responses are calculated. In addition, we analytically investigate the cutoff frequencies of DFA and DMA detrending operations and show that these frequencies are not optimally adjusted to coincide with the corresponding time scale.

Patient Versus Physician Variation in Use of Transradial Percutaneous Coronary Intervention.

PubMed

Shamim, Shariq; Tang, Fengming; Safley, David; Jones, Philip; Spertus, John A; Baklanov, Dmitri

2017-06-15

The prevalence of radial access for transradial catheterization remains low in the United States, occurring in only 28% of cases in the National Cardiovascular Data Registry (NCDR) CathPCI. It is unknown whether the low adoption rate has been influenced by patient characteristics or is more operator dependent. In a 10-center study, we compared clinical and demographic characteristics among 323 radial and 1,506 femoral access percutaneous coronary intervention (PCIs) performed by 65 interventionists capable of radial PCI. We created a hierarchical logistic regression model to identify operator and patient characteristics associated with radial PCI and the median rate ratio to quantify the variation across operators. A subset was interviewed to assess health literacy and preferences in shared medical decision making. Radial access was used in 17.7% of patients. Patient factors associated with lower rate of radial PCI were previous PCI (33.4% vs 41.4%, p = 0.008), history of coronary artery bypass graft (8.4% vs 23.0%, p <0.001), and chronic total occlusion PCI (10.2% vs 17.9%, p <0.001). Operator characteristics associated with lower rate of radial PCI are being older, being longer in practice, lower number of publications, and Southern practice location. The range of radial use across operators was 1% to 99% and the median rate ratio was 1.97. Patients with radial access had lower health literacy, as assessed by the Rapid Estimate of Adult Literacy in Medicine Revised (REALM) score (6.6 ± 2.6 vs 7.1 ± 2.0, p = 0.03) but did not differ in their preferences for shared decision making. In conclusion, our study demonstrates a high degree of variability of radial access for PCI among different operators, with few differences in patient characteristics, suggesting that improvement efforts should focus on operators. Copyright © 2017 Elsevier Inc. All rights reserved.

The effect of applied control strategy on the current-voltage correlation of a solid oxide fuel cell stack during dynamic operation

NASA Astrophysics Data System (ADS)

Szmyd, Janusz S.; Komatsu, Yosuke; Brus, Grzegorz; Ghigliazza, Francesco; Kimijima, Shinji; Ściążko, Anna

2014-09-01

This paper discusses the transient characteristics of the planar type SOFC cell stack, of which the standard output is 300 W. The transient response of the voltage to the manipulation of an electric current was investigated. The effects of the response and of the operating condition determined by the operating temperature of the stack were studied by mapping a current-voltage (I-V) correlation. The current-based fuel control (CBFC) was adopted for keeping the fuel utilization factor at constant while the value of the electric current was ramped at the constant rate. The present experimental study shows that the transient characteristics of the cell voltage are determined by primarily the operating temperature caused by the manipulation of the current. Particularly, the slope of the I-V curve and the overshoot found on the voltage was remarkably influenced by the operating temperature. The different values of the fuel utilization factor influence the height of the settled voltages. The CBFC has significance in determining the slope of the I-V characteristic, but the different values ofthe fuel utilization factor does not affect the slope as the operating temperature does. The CBFC essentially does not alter the amplitude of the overshoot on the voltage response, since this is dominated by the operating temperature and its change is caused by manipulating the current.

The Factor Structure of Concrete and Formal Operations: A Confirmation of Piaget.

ERIC Educational Resources Information Center

Gray, William M.

Piaget has hypothesized that concrete and formal operations can be described by specific logical models. The present study focused on assessing various aspects of four concrete operational groupings and two variations of two formal operational characteristics. Six hundred twenty-two 9-14 year old students participating in the Human Sciences…

Offshore wind development research (technical brief).

DOT National Transportation Integrated Search

2014-04-01

The study addresses all aspects of Offshore Wind (OSW) development. This includes identifying : vessel types, vessel installation methods, needs and operating characteristics through all phases : of OSW installation, construction, operations and main...

A case study of experimental passing zones on Route 8 in Patrick County.

DOT National Transportation Integrated Search

1982-01-01

This study examined the operational characteristics of the four-mile section of Route 8 between Routes 57 and 58. It was noted that these characteristics were significantly improved after provision of the experimental passing zones. Average and 85th ...

Operational and safety characteristics of lane widths : final report.

DOT National Transportation Integrated Search

2015-01-15

The primary goal of this study was to investigate and assess the effect of lane widths on the safety and : operation of highways in South Carolina. Because of the many site conditions that affect safety and : operations on roadways, this type of rese...

Dual operation characteristics of resistance random access memory in indium-gallium-zinc-oxide thin film transistors

NASA Astrophysics Data System (ADS)

Yang, Jyun-Bao; Chang, Ting-Chang; Huang, Jheng-Jie; Chen, Yu-Chun; Chen, Yu-Ting; Tseng, Hsueh-Chih; Chu, Ann-Kuo; Sze, Simon M.

2014-04-01

In this study, indium-gallium-zinc-oxide thin film transistors can be operated either as transistors or resistance random access memory devices. Before the forming process, current-voltage curve transfer characteristics are observed, and resistance switching characteristics are measured after a forming process. These resistance switching characteristics exhibit two behaviors, and are dominated by different mechanisms. The mode 1 resistance switching behavior is due to oxygen vacancies, while mode 2 is dominated by the formation of an oxygen-rich layer. Furthermore, an easy approach is proposed to reduce power consumption when using these resistance random access memory devices with the amorphous indium-gallium-zinc-oxide thin film transistor.

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

Logan, Jeffrey S.; Paranhos, Elizabeth; Kozak, Tracy G.

This study focuses on onshore natural gas operations and examines the extent to which oil and gas firms have embraced certain organizational characteristics that lead to 'high reliability' - understood here as strong safety and reliability records over extended periods of operation. The key questions that motivated this study include whether onshore oil and gas firms engaged in exploration and production (E&P) and midstream (i.e., natural gas transmission and storage) are implementing practices characteristic of high reliability organizations (HROs) and the extent to which any such practices are being driven by industry innovations and standards and/or regulatory requirements.

Building Assessment Survey and Evaluation (BASE) Study: Summarized Data - Test Space HVAC Characteristics

EPA Pesticide Factsheets

Information on the characteristics of the heating, ventilation, and air conditioning (HVAC) system(s) in the entire BASE building including types of ventilation, equipment configurations, and operation and maintenance issues

Orbit Transfer Vehicle (OTV) advanced expander cycle engine point design study. Volume 3: Engine data summary

NASA Technical Reports Server (NTRS)

1981-01-01

The engine operating characteristics were examined. Inlet pressure effects, tank pressurization effects, steady-state specific impulse, and the steady-state cycle were studied. The propellant flow schematic and operating sequence are presented. Engine hardware drawings are included.

Influence of median surgeon operative duration on adverse outcomes in bariatric surgery.

PubMed

Reames, Bradley N; Bacal, Daniel; Krell, Robert W; Birkmeyer, John D; Birkmeyer, Nancy J O; Finks, Jonathan F

2015-01-01

Evidence suggests that prolonged operative time adversely affects surgical outcomes. However, whether faster surgeons have better outcomes is unclear, as a surgeon׳s speed could reflect skill and efficiency, but may alternatively reflect haste. This study evaluates whether median surgeon operative time is associated with adverse surgical outcomes after laparoscopic Roux-en-Y gastric bypass. We performed a retrospective cohort study using statewide clinical registry data from the years 2006 to 2012. Surgeons were ranked by their median operative time and grouped into terciles. Multivariable logistic regression with robust standard errors was used to evaluate the influence of median surgeon operative time on 30-day surgical outcomes, adjusting for patient and surgeon characteristics, trainee involvement, concurrent procedures, and the complex interaction between these variables. A total of 16,344 patients underwent surgery during the study period. Compared to surgeons in the fastest tercile, slow surgeons required 53 additional minutes to complete a gastric bypass procedure (median [interquartile range] 139 [133-150] versus 86 [69-91], P<.001). After adjustment for patient characteristic only, slow surgeons had significantly higher adjusted rates of any complication, prolonged length of stay, emergency department visits or readmissions, and venous thromboembolism (VTE). After further adjustment for surgeon characteristics, resident involvement, and the interaction between these variables, slow surgeons had higher rates of any complication (10.5% versus 7.1%, P=.039), prolonged length of stay (14.0% versus 4.4%, P=.002), and VTE (0.39% versus .22%, P<.001). Median surgeon operative duration is independently associated with adjusted rates of certain adverse outcomes after laparoscopic Roux-en-Y gastric bypass. Improving surgeon efficiency while operating may reduce operative time and improve the safety of bariatric surgery. Copyright © 2015 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

Clinical usefulness of the definitions for defining characteristics of activity intolerance, excess fluid volume and decreased cardiac output in decompensated heart failure: a descriptive exploratory study.

PubMed

de Souza, Vanessa; Zeitoun, Sandra Salloum; Lopes, Camila Takao; de Oliveira, Ana Paula Dias; Lopes, Juliana de Lima; de Barros, Alba Lucia Bottura Leite

2015-09-01

To assess the clinical usefulness of the operational definitions for the defining characteristics of the NANDA International nursing diagnoses, activity intolerance, decreased cardiac output and excess fluid volume, and the concomitant presence of those diagnoses in patients with decompensated heart failure. Content validity of the operational definitions for the defining characteristics of activity intolerance, excess fluid volume and decreased cardiac output have been previously validated by experts. Their clinical usefulness requires clinical validation. This was a descriptive exploratory study. Two expert nurses independently assessed 25 patients with decompensated heart failure for the presence or absence of 29 defining characteristics. Interrater reliability was analysed using the Kappa coefficient as a measure of clinical usefulness. The Fisher's exact test was used to test the association of the defining characteristics of activity intolerance and excess fluid volume in the presence of decreased cardiac output, and the correlation between the three diagnoses. Assessments regarding the presence of all defining characteristics reached 100% agreement, except with anxiety. Five defining characteristics of excess fluid volume were significantly associated with the presence of decreased cardiac output. Concomitant presence of the three diagnoses occurred in 80% of the patients. However, there was no significant correlation between the three diagnoses. The operational definitions for the diagnoses had strong interrater reliability, therefore they were considered clinically useful. Only five defining characteristics were representative of the association between excess fluid volume and decreased cardiac output. Therefore, excess fluid volume is related to decreased cardiac output, although these diagnoses are not necessarily associated with activity intolerance. The operational definitions may favour early recognition of the sequence of responses to decompensation, guiding the choice of common interventions to improve or resolve excess fluid volume and decreased cardiac output. © 2015 John Wiley & Sons Ltd.

Clinical characteristics and outcomes of septic bursitis.

PubMed

Lieber, Sarah B; Fowler, Mary Louise; Zhu, Clara; Moore, Andrew; Shmerling, Robert H; Paz, Ziv

2017-12-01

Limited data guide practice in evaluation and treatment of septic bursitis. We aimed to characterize clinical characteristics, microbiology, and outcomes of patients with septic bursitis stratified by bursal involvement, presence of trauma, and management type. We conducted a retrospective cohort study of adult patients admitted to a single center from 1998 to 2015 with culture-proven olecranon and patellar septic bursitis. Baseline characteristics, clinical features, microbial profiles, operative interventions, hospitalization lengths, and 60-day readmission rates were determined. Patients were stratified by bursitis site, presence or absence of trauma, and operative or non-operative management. Of 44 cases of septic bursitis, patients with olecranon and patellar bursitis were similar with respect to age, male predominance, and frequency of bursal trauma; patients managed operatively were younger (p = 0.05). Clinical features at presentation and comorbidities were similar despite bursitis site, history of trauma, or management. The most common organism isolated from bursal fluid was Staphylococcus aureus. Patients managed operatively were discharged to rehabilitation less frequently (p = 0.04). This study of septic bursitis is among the largest reported. We were unable to identify presenting clinical features that differentiated patients treated surgically from those treated conservatively. There was no clear relationship between preceding trauma or bursitis site and clinical course, management, or outcomes. Patients with bursitis treated surgically were younger. Additional study is needed to identify patients who would benefit from early surgical intervention for septic bursitis.

Truck characteristics for use in highway design and operation. Volume II, Appendices

DOT National Transportation Integrated Search

1990-08-01

Highway geometric design and traffic operations are based in part on consideration of vehicle characteristics. However, many of the current highway design and operational criteria are based on passenger car characteristics, even though truck characte...

49 CFR 236.717 - Characteristics, operating.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Characteristics, operating. 236.717 Section 236.717 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... § 236.717 Characteristics, operating. The measure of electrical values at which electrical or electronic...

49 CFR 236.717 - Characteristics, operating.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Characteristics, operating. 236.717 Section 236.717 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... § 236.717 Characteristics, operating. The measure of electrical values at which electrical or electronic...

The short-term effects of merger on hospital operations.

PubMed Central

Alexander, J A; Halpern, M T; Lee, S Y

1996-01-01

OBJECTIVE: The short-term effects of merger on three areas of hospital operations - scale of activity, personnel/staffing practices, and operating efficiency - is examined. DATA SOURCES: Secondary data obtained from the AHA Annual Surveys (1980-1990) were applied to analyze 92 hospital mergers over the period 1982-1989. STUDY DESIGN: The study employed a multiple time-series design involving a six-year longitudinal assessment of change in hospital operating characteristics before and after merger, and a parallel analysis of change in a randomly selected group of nonmerging hospitals. DATA COLLECTION: Pooled, cross-sectional data files were constructed. Comparisons were evaluated using paired and two-sample t-tests. PRINCIPAL FINDINGS: General merger effects occurred primarily in areas related to operating efficiency. Merger resulted in slowing rates of preexisting trends, rather than dramatic improvements in operating practices. CONCLUSIONS: The short-term impact of merger was generally modest but differed by the conditions under which the merger occurred. Specifically, mergers occurring later in the study period and mergers between similarly sized hospitals displayed greater change in operating characteristics than those occurring earlier in the study period and those between hospitals of dissimilar size. Such differences are attributed respectively to increased competitive pressures after PPS and to greater opportunities for consolidation and efficiencies in mergers involving similarly sized hospitals. PMID:8591932

Electrochemical models for the discharge characteristics of the nickel cadmium cell

NASA Technical Reports Server (NTRS)

Spritzer, M. S.

1981-01-01

The potential time characteristics of a preconditioned fully charged cell discharge at constant current was studied. Electrochemical principles applied to the sealed nickel cadmium cell and its behavior and to predict operating characteristics were described. A thermodynamic approach to arrive at several related but different equations and its discharge are reported.

A 100 kW experimental wind turbine: Simulation of starting, overspeed, and shutdown characteristics

NASA Technical Reports Server (NTRS)

Gilbert, L. J.

1976-01-01

The ERDA/NASA 100 kW experimental wind turbine is modeled on a digital computer in order to study the performance of a wind turbine under operating conditions. Simulation studies of starting, overspeed, and shutdown performance were made. From these studies operating procedures, precautions, and limitations are prescribed.

Characterization of advanced electric propulsion systems

NASA Technical Reports Server (NTRS)

Ray, P. K.

1982-01-01

Characteristics of several advanced electric propulsion systems are evaluated and compared. The propulsion systems studied are mass driver, rail gun, MPD thruster, hydrogen free radical thruster and mercury electron bombardment ion engine. These are characterized by specific impulse, overall efficiency, input power, average thrust, power to average thrust ratio and average thrust to dry weight ratio. Several important physical characteristics such as dry system mass, accelerator length, bore size and current pulse requirement are also evaluated in appropriate cases. Only the ion engine can operate at a specific impulse beyond 2000 sec. Rail gun, MPD thruster and free radical thruster are currently characterized by low efficiencies. Mass drivers have the best performance characteristics in terms of overall efficiency, power to average thrust ratio and average thrust to dry weight ratio. But, they can only operate at low specific impulses due to large power requirements and are extremely long due to limitations of driving current. Mercury ion engines have the next best performance characteristics while operating at higher specific impulses. It is concluded that, overall, ion engines have somewhat better characteristics as compared to the other electric propulsion systems.

Dynamic characteristics of single crystal SSME blades

NASA Technical Reports Server (NTRS)

Moss, L. A.; Smith, T. E.

1987-01-01

The Space Shuttle Main Engine (SSME) High Pressure Fuel Turbopump (HPFTP) blades are currently manufactured using a directionally solidified (DS) material, MAR-M-246+Hf. However, a necessity to reduce the occurrence of fatigue cracking within the DS blades has lead to an interest in the use of a single crystal (SC) material, PWA-1480. A study was initiated to determine the dynamic characteristics of the HPFTP blades made of SC material and find possible critical engine order excitations. This study examined both the first and second stage drive turbine blades of the HPFTP. The dynamic characterization was done analytically as well as experimentally. The analytical study examined the SC first stage HPFTP blade dynamic characteristics under typical operating conditions. The blades were analyzed using MSC/NASTRAN and a finite element model. Two operating conditions, 27500 RPM and 35000 RPM, were investigated.

Fixation of operating point and measurement of turn on characteristics of IGBT F4-75R06W1E3

NASA Astrophysics Data System (ADS)

Haseena, A.; Subhash Joshi T., G.; George, Saly

2018-05-01

For the proficient operation of the Power electronic circuit, signal level performance of power electronic devices are very important. For getting good signal level characteristics, fixing operating point is very critical. Device deviates from the typical characteristics given in the datasheet due to the presence of stray components in the circuit lay out. Fixation of operating point of typical silicon IGBT and its turn on characteristics is discussed in this paper.

Assisted care as a baseline patient risk characteristic affecting the outcome of transcatheter aortic valve insertion.

PubMed

Traynor, Megan M; Greason, Kevin L; Nkomo, Vuyisile T; Pochettino, Alberto; Holmes, David R; Rihal, Charanjit S; Reeder, Guy S; Bresnahan, John F; Mathew, Verghese

2017-06-01

Objective measures of frailty have not been well defined as risk factors for a poor outcome after transcatheter aortic valve insertion. We hypothesized that assisted care as a baseline patient characteristic was a simple objective measure of frailty. We reviewed our experience to assess for an association between assisted care and outcome of operation. We retrospectively reviewed the records of 597 patients operated with transcatheter aortic valve insertion from November 2008 through July 2015. The study cohort included patients with a dichotomous baseline characteristic of receiving assisted care (AC group, n = 60, 10.1%) or not receiving assisted care (NC group, n = 537, 89.9%). The endpoints of the study were operative stroke/death and 1-year survival. The age of the patients was 80.6 ± 9.0 years, male sex was present in 349 (58.5%), and STS predicted risk of mortality was 9.2 ± 6.2%. Alternate access was used in 26 (43.3%) patients in the AC care group and in 220 (41.0%) in the NC group (P = 0.724). Operative stroke/death occurred in 4 (6.7%) patients in the AC group and in 25 (4.7%) in the NC group (P = 0.492). Mortality at 1 year in the AC group was 14.8 ± 5.2% and in the NC group was 12.9 ± 1.7%; (P = 0. 250). Assisted care as a baseline patient characteristic does not result in increased operative stroke/death or 1-year mortality in patients following transcatheter aortic valve insertion. Assisted care should not by itself preclude operation. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Validation of a Predictive Scoring System for Deep Sternal Wound Infection after Bilateral Internal Thoracic Artery Grafting in a Cohort of French Patients.

PubMed

Perrotti, Andrea; Gatti, Giuseppe; Dorigo, Enrica; Sinagra, Gianfranco; Pappalardo, Aniello; Chocron, Sidney

The Gatti score is a weighted scoring system based on risk factors for deep sternal wound infection (DSWI) that was created in an Italian center to predict DSWI risk after bilateral internal thoracic artery (BITA) grafting. No external evaluation based on validation samples derived from other surgical centers has been performed. The aim of this study is to perform this validation. During 2015, BITA grafts were used as skeletonized conduits in all 255 consecutive patients with multi-vessel coronary disease who underwent isolated coronary bypass surgery at the Department of Thoracic and Cardio-Vascular Surgery, University Hospital Jean Minjoz, Besançon, France. Baseline characteristics, operative data, and immediate outcomes of every patient were collected prospectively. A DSWI risk score was assigned to each patient pre-operatively. The discrimination power of both models, pre-operative and combined, of the Gatti score was assessed with the calculation of the area under the receiver operating characteristic curve. Fourteen (5.5%) patients had DSWI. Major differences both as the baseline characteristics of patients and surgical techniques were found between this series and the original series from which the Gatti score was derived. The area under the receiver operating characteristic curve was 0.78 (95% confidence interval: 0.64-0.92) for the pre-operative model and 0.84 (95% confidence interval: 0.69-0.98) for the combined model. The Gatti score has proven to be effective even in a cohort of French patients despite major differences from the original Italian series. Multi-center validation studies must be performed before introducing the score into clinical practice.

District Survey I. Policy Research Corporation Analyses. Final Report.

ERIC Educational Resources Information Center

Policy Research Corp., Chicago, IL.

This study, mandated by Congress in the Education Amendments of 1974, was designed to produce estimates which describe the goals of compensatory programs, program operating characteristics, and evaluation techniques in use in compensatory programs. For the purpose of the study, the population sample was defined as all operating public school…

Operational Maneuver: Function or Fiction?

DTIC Science & Technology

1996-02-12

characteristics of Vego’s operational functions. Although Schroedel’s model was constructed for the art and science of operational maneuver, his model...Schroedel, Joseph. "The Art and Science of operational Maneuver. " Fort Leavenworth, Kansas, SAMS Monograph, 1988, p. 5. 3 U.S. Joint Chiefs of Staff...Important Than Others? Ft. Leavenworth, Kansas: Study, 1986. Schroedel, Joseph. "The Art and Science of Operational Maneuver." Ft. Leavenworth, Kansas: SAMS

Investigating the effect of characteristic x-rays in cadmium zinc telluride detectors under breast computerized tomography operating conditions

PubMed Central

Glick, Stephen J.; Didier, Clay

2013-01-01

A number of research groups have been investigating the use of dedicated breast computerized tomography (CT). Preliminary results have been encouraging, suggesting an improved visualization of masses on breast CT as compared to conventional mammography. Nonetheless, there are many challenges to overcome before breast CT can become a routine clinical reality. One potential improvement over current breast CT prototypes would be the use of photon counting detectors with cadmium zinc telluride (CZT) (or CdTe) semiconductor material. These detectors can operate at room temperature and provide high detection efficiency and the capability of multi-energy imaging; however, one factor in particular that limits image quality is the emission of characteristic x-rays. In this study, the degradative effects of characteristic x-rays are examined when using a CZT detector under breast CT operating conditions. Monte Carlo simulation software was used to evaluate the effect of characteristic x-rays and the detector element size on spatial and spectral resolution for a CZT detector used under breast CT operating conditions. In particular, lower kVp spectra and thinner CZT thicknesses were studied than that typically used with CZT based conventional CT detectors. In addition, the effect of characteristic x-rays on the accuracy of material decomposition in spectral CT imaging was explored. It was observed that when imaging with 50-60 kVp spectra, the x-ray transmission through CZT was very low for all detector thicknesses studied (0.5–3.0 mm), thus retaining dose efficiency. As expected, characteristic x-ray escape from the detector element of x-ray interaction increased with decreasing detector element size, approaching a 50% escape fraction for a 100 μm size detector element. The detector point spread function was observed to have only minor degradation with detector element size greater than 200 μm and lower kV settings. Characteristic x-rays produced increasing distortion in the spectral response with decreasing detector element size. If not corrected for, this caused a large bias in estimating tissue density parameters for material decomposition. It was also observed that degradation of the spectral response due to characteristic x-rays caused worsening precision in the estimation of tissue density parameters. It was observed that characteristic x-rays do cause some degradation in the spatial and spectral resolution of thin CZT detectors operating under breast CT conditions. These degradations should be manageable with careful selection of the detector element size. Even with the observed spectral distortion from characteristic x-rays, it is still possible to correctly estimate tissue parameters for material decomposition using spectral CT if accurate modeling is used. PMID:24187383

Chaotic behaviors of operational amplifiers.

PubMed

Yim, Geo-Su; Ryu, Jung-Wan; Park, Young-Jai; Rim, Sunghwan; Lee, Soo-Young; Kye, Won-Ho; Kim, Chil-Min

2004-04-01

We investigate nonlinear dynamical behaviors of operational amplifiers. When the output terminal of an operational amplifier is connected to the inverting input terminal, the circuit exhibits period-doubling bifurcation, chaos, and periodic windows, depending on the voltages of the positive and the negative power supplies. We study these nonlinear dynamical characteristics of this electronic circuit experimentally.

Space tug point design study. Volume 2: Operations, performance and requirements

NASA Technical Reports Server (NTRS)

1973-01-01

A design study to determine the configuration and characteristics of a space tug was conducted. Among the subjects analyzed in the study are: (1) flight and ground operations, (2) vehicle flight performance and performance enhancement techniques, (3) flight requirements, (4) basic design criteria, and (5) functional and procedural interface requirements between the tug and other systems.

Structural and biomechanical characteristics after early mobilization in an Achilles tendon rupture model: operative versus nonoperative treatment.

PubMed

Krapf, Daniel; Kaipel, Martin; Majewski, Martin

2012-09-01

Acute Achilles tendon ruptures are common sports injuries; however, treatment remains a clinical challenge. Studies show a superior effect of early mobilization and full weight bearing on tendon healing and clinical outcome; however, few data exist on structural and biomechanical characteristics in the early healing phase. This study investigated the histological and biomechanical characteristics of early mobilization and full weight bearing in an Achilles tendon rupture model. Eighty rats underwent dissection of a hindpaw Achilles tendon; 40 rats were treated conservatively and 40 underwent open repair of the transected Achilles tendon by suturing. Early mobilization and full weight bearing were allowed in both groups. At 1, 2, 4, and 8 weeks after tenotomy, tensile strength, stiffness, thickness, tissue characteristics (histological analysis), and length were determined. Dissected Achilles tendons healed in all animals during full weight-bearing early mobilization. One and 2 weeks after tenotomy, rats in the operative group showed increased tensile strength and stiffness compared with the nonoperative group. Repair-site diameters were increased at 1, 2, and 8 weeks after tenotomy. Tendon length was decreased in the operative group throughout observation, whereas the nonoperative group showed increased structural characteristics on the cellular level and a more homogeneous collagen distribution. Surgical treatment of dissected rat Achilles tendons showed superior biomechanical characteristics within the first 2 weeks. Conservative treatment resulted in superior histological findings but significant lengthening of the tendon in the early healing phase (weeks 1-8). Copyright 2012, SLACK Incorporated.

Control of a 30 cm diameter mercury bombardment thruster

NASA Technical Reports Server (NTRS)

Terdan, F. F.; Bechtel, R. T.

1973-01-01

Increased thruster performance has made closed-loop automatic control more difficult than previously. Specifically, high perveance optics tend to make reliable recycling more difficult. Control logic functions were established for three automatic modes of operation of a 30-cm thruster using a power conditioner console with flight-like characteristics. The three modes provide (1) automatic startup to reach thermal stability, (2) steady-state closed-loop control, and (3) the reliable recycling of the high voltages following an arc breakdown to reestablish normal operation. Power supply impedance characteristics necessary for stable operation and the effect of the magnetic baffle on the reliable recycling was studied.

Measurement and analysis of operating system fault tolerance

NASA Technical Reports Server (NTRS)

Lee, I.; Tang, D.; Iyer, R. K.

1992-01-01

This paper demonstrates a methodology to model and evaluate the fault tolerance characteristics of operational software. The methodology is illustrated through case studies on three different operating systems: the Tandem GUARDIAN fault-tolerant system, the VAX/VMS distributed system, and the IBM/MVS system. Measurements are made on these systems for substantial periods to collect software error and recovery data. In addition to investigating basic dependability characteristics such as major software problems and error distributions, we develop two levels of models to describe error and recovery processes inside an operating system and on multiple instances of an operating system running in a distributed environment. Based on the models, reward analysis is conducted to evaluate the loss of service due to software errors and the effect of the fault-tolerance techniques implemented in the systems. Software error correlation in multicomputer systems is also investigated.

Feasibility Analysis of UAV Technology to Improve Tactical Surveillance in South Korea’s Rear Area Operations

DTIC Science & Technology

2017-03-01

determine the optimum required operational capability of the unmanned aerial vehicles to support Korean rear area operations. We use Map Aware Non ...area operations. Through further experimentations and analyses, we were able to find the optimum characteristics of an improved unmanned aerial...operations. We use Map Aware Non -Uniform Automata, an agent-based simulation software platform for computational experiments. The study models a scenario

Second branchial cleft fistulae: patient characteristics and surgical outcome.

PubMed

Kajosaari, Lauri; Mäkitie, Antti; Salminen, Päivi; Klockars, Tuomas

2014-09-01

Second branchial cleft anomalies predispose to recurrent infections, and surgical resection is recommended as the treatment of choice. There is no clear consensus regarding the timing or surgical technique in the operative treatment of these anomalies. Our aim was to compare the effect of age and operative techniques to patient characteristics and treatment outcome. A retrospective study of pediatric patients treated for second branchial sinuses or fistulae during 1998-2012 at two departments in our academic tertiary care referral center. Comparison of patient characteristics, preoperative investigations, surgical techniques and postoperative sequelae. Our data is based on 68 patients, the largest series in the literature. One-fourth (24%) of patients had any infectious symptoms prior to operative treatment. Patient demographics, preoperative investigations, use of methylene blue, or tonsillectomy had no effect on the surgical outcome. There were no re-operations due to residual disease. Three complications were observed postoperatively. Our patient series of second branchial cleft sinuses/fistulae is the largest so far and enables analyses of patient characteristics and surgical outcomes more reliably than previously. Preoperative symptoms are infrequent and mild. There was no difference in clinical outcome between the observed departments. Performing ipsilateral tonsillectomy gave no outcome benefits. The operation may be delayed to an age of approximately three years when anesthesiological risks are and possible harms are best avoided. Considering postoperative pain and risk of postoperative hemorrhage a routine tonsillectomy should not be included to the operative treatment of second branchial cleft fistulae. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Adolescent Bariatric Surgery Program Characteristics: The Teen Longitudinal Assessment of Bariatric Surgery (Teen-LABS) Study Experience

PubMed Central

Michalsky, M.P.; Inge, T.H.; Teich, S.; Eneli, I.; Miller, R.; Brandt, M.L.; Helmrath, M.; Harmon, C.M.; Zeller, M.H.; Jenkins, T.M.; Courcoulas, A.; Buncher, C.R.

2013-01-01

Background The number of adolescents undergoing weight loss surgery (WLS) has increased in response to the increasing prevalence of severe childhood obesity. Adolescents undergoing WLS require unique support, which may differ from adult programs. The aim of this study was to describe institutional and programmatic characteristics of centers participating in Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS), a prospective study investigating safety and efficacy of adolescent WLS. Methods Data were obtained from the Teen-LABS database and site survey completed by Teen-LABS investigators. The survey queried (1) institutional characteristics, (2) multidisciplinary team composition, (3) clinical program characteristics, and (4) clinical research infrastructure. Results All centers had extensive multidisciplinary involvement in the assessment, preoperative education and post-operative management of adolescents undergoing WLS. Eligibility criteria, pre-operative clinical and diagnostic evaluations were similar between programs. All programs have well developed clinical research infrastructure, use adolescent-specific educational resources, and maintain specialty equipment, including high weight capacity diagnostic imaging equipment. Conclusions The composition of clinical team and institutional resources are consistent with current clinical practice guidelines. These characteristics, coupled with dedicated research staff, have facilitated enrollment of 242 participants into Teen-LABS. PMID:24491361

Systems Operation Studies for Automated Guideway Transit Systems - Classification and Definition of AGT Systems

DOT National Transportation Integrated Search

1980-02-01

The report describes the development of an AGT classification structure. Five classes are defined based on three system characteristics: service type, minimum travelling unit capacity, and maximum operating velocity. The five classes defined are: Per...

V/STOL tilt-rotor study, task 1. Volume 1: Conceptual design

NASA Technical Reports Server (NTRS)

1972-01-01

A conceptual design study was conducted to define a representative military and/or commercial tilt-propeller aircraft for short takeoff and landing operation. The level of structural technology selected for the operational aircraft was based on aluminum, steel, titanium, and adhesive bonded structures. The data describe the following: (1) aircraft weight, (2) performance and stability, (3) aerodynamic noise, (4) dynamic characteristics, (5) maintainability and reliability, and (6) operating economics.

Improving the environmental and performance characteristics of vehicles by introducing the surfactant additive into gasoline.

PubMed

Magaril, Elena; Magaril, Romen

2016-09-01

The operation of modern vehicles requires the introduction of package of fuel additives to ensure the required level of operating characteristics, some of which cannot be achieved by current oil refining methods. The use of additives allows flexibility of impact on the properties of the fuel at minimal cost, increasing the efficiency and environmental safety of vehicles. Among the wide assortment of additives available on the world market, many are surfactants. It has been shown that the introduction of some surfactants into gasoline concurrently reduces losses from gasoline evaporation, improves the mixture formation during injection of gasoline into the engine and improves detergent and anticorrosive properties. The surfactant gasoline additive that provides significant improvement in the quality of gasoline used and environmental and operating characteristics of vehicles has been developed and thoroughly investigated. The results of studies confirming the efficiency of the gasoline additive application are herein presented.

Operation of staged membrane oxidation reactor systems

DOEpatents

Repasky, John Michael

2012-10-16

A method of operating a multi-stage ion transport membrane oxidation system. The method comprises providing a multi-stage ion transport membrane oxidation system with at least a first membrane oxidation stage and a second membrane oxidation stage, operating the ion transport membrane oxidation system at operating conditions including a characteristic temperature of the first membrane oxidation stage and a characteristic temperature of the second membrane oxidation stage; and controlling the production capacity and/or the product quality by changing the characteristic temperature of the first membrane oxidation stage and/or changing the characteristic temperature of the second membrane oxidation stage.

Personality Factors and the Driving Task.

ERIC Educational Resources Information Center

Kenel, Francis C.

This booklet reviews several research studies in light of the possibility of identifying certain behavioral characteristics and the relationship of the characteristics to vehicle operator performance. Focus is on implications for driver education. A short introductory section describes the development of the Mann Inventory for categorizing…

Assessing the financial characteristics of multi-institutional organizations.

PubMed Central

Coyne, J S

1985-01-01

The prospective pricing of health services is precipitating greater attention to financial characteristics and greater development of multi-institutional organizations (MIOs). This study compares the financial characteristics of 1,590 MIO hospitals with 2,819 freestanding hospitals by ownership type: church-operated, other not-for-profit, and investor-owned. Using 1981 data from the American Hospital Association, the hospitals' capital structure and profitability are measured using three financial ratios: total assets-to-equity, return on equity, and operating margin. The results indicate both greater leverage and greater profitability among MIO hospitals, particularly in the investor-owned sector. The implications of these findings are discussed relative to financial performance by hospital ownership type in the future. PMID:4038697

Assessing the financial characteristics of multi-institutional organizations.

PubMed

Coyne, J S

1985-02-01

The prospective pricing of health services is precipitating greater attention to financial characteristics and greater development of multi-institutional organizations (MIOs). This study compares the financial characteristics of 1,590 MIO hospitals with 2,819 freestanding hospitals by ownership type: church-operated, other not-for-profit, and investor-owned. Using 1981 data from the American Hospital Association, the hospitals' capital structure and profitability are measured using three financial ratios: total assets-to-equity, return on equity, and operating margin. The results indicate both greater leverage and greater profitability among MIO hospitals, particularly in the investor-owned sector. The implications of these findings are discussed relative to financial performance by hospital ownership type in the future.

Development of a superconductor magnetic suspension and balance prototype facility for studying the feasibility of applying this technique to large scale aerodynamic testing

NASA Technical Reports Server (NTRS)

Zapata, R. N.; Humphris, R. R.; Henderson, K. C.

1975-01-01

The basic research and development work towards proving the feasibility of operating an all-superconductor magnetic suspension and balance device for aerodynamic testing is presented. The feasibility of applying a quasi-six-degree-of freedom free support technique to dynamic stability research was studied along with the design concepts and parameters for applying magnetic suspension techniques to large-scale aerodynamic facilities. A prototype aerodynamic test facility was implemented. Relevant aspects of the development of the prototype facility are described in three sections: (1) design characteristics; (2) operational characteristics; and (3) scaling to larger facilities.

Street vending and informal economy: Survey data from Cali, Colombia.

PubMed

Martinez, Lina M; Estrada, Daniela

2017-10-01

This data brief describes data collected in Cali, Colombia about the economic dynamic and socioeconomic conditions of street vendors in the city. The study was conducted between 2014 and 2016 in two populated sites in terms of formal and informal commerce in the city. We present the methodology followed in the study, location of street vending sites and type of data collected to approximate to the economic dimension of street vending. Data collected contains information about sociodemographic characteristics, life satisfaction, business operation and characteristics, income and expenses, official license for operation. This information is linked to the publication (Martinez et al., 2017) [1].

Characteristic classes of gauge systems

NASA Astrophysics Data System (ADS)

Lyakhovich, S. L.; Sharapov, A. A.

2004-12-01

We define and study invariants which can be uniformly constructed for any gauge system. By a gauge system we understand an (anti-)Poisson supermanifold provided with an odd Hamiltonian self-commuting vector field called a homological vector field. This definition encompasses all the cases usually included into the notion of a gauge theory in physics as well as some other similar (but different) structures like Lie or Courant algebroids. For Lagrangian gauge theories or Hamiltonian first class constrained systems, the homological vector field is identified with the classical BRST transformation operator. We define characteristic classes of a gauge system as universal cohomology classes of the homological vector field, which are uniformly constructed in terms of this vector field itself. Not striving to exhaustively classify all the characteristic classes in this work, we compute those invariants which are built up in terms of the first derivatives of the homological vector field. We also consider the cohomological operations in the space of all the characteristic classes. In particular, we show that the (anti-)Poisson bracket becomes trivial when applied to the space of all the characteristic classes, instead the latter space can be endowed with another Lie bracket operation. Making use of this Lie bracket one can generate new characteristic classes involving higher derivatives of the homological vector field. The simplest characteristic classes are illustrated by the examples relating them to anomalies in the traditional BV or BFV-BRST theory and to characteristic classes of (singular) foliations.

Experimental Design and Data Analysis in Receiver Operating Characteristic Studies: Lessons Learned from Reports in Radiology from 1997 to 20061

PubMed Central

Shiraishi, Junji; Pesce, Lorenzo L.; Metz, Charles E.; Doi, Kunio

2009-01-01

Purpose: To provide a broad perspective concerning the recent use of receiver operating characteristic (ROC) analysis in medical imaging by reviewing ROC studies published in Radiology between 1997 and 2006 for experimental design, imaging modality, medical condition, and ROC paradigm. Materials and Methods: Two hundred ninety-five studies were obtained by conducting a literature search with PubMed with two criteria: publication in Radiology between 1997 and 2006 and occurrence of the phrase “receiver operating characteristic.” Studies returned by the query that were not diagnostic imaging procedure performance evaluations were excluded. Characteristics of the remaining studies were tabulated. Results: Two hundred thirty-three (79.0%) of the 295 studies reported findings based on observers' diagnostic judgments or objective measurements. Forty-three (14.6%) did not include human observers, with most of these reporting an evaluation of a computer-aided diagnosis system or functional data obtained with computed tomography (CT) or magnetic resonance (MR) imaging. The remaining 19 (6.4%) studies were classified as reviews or meta-analyses and were excluded from our subsequent analysis. Among the various imaging modalities, MR imaging (46.0%) and CT (25.7%) were investigated most frequently. Approximately 60% (144 of 233) of ROC studies with human observers published in Radiology included three or fewer observers. Conclusion: ROC analysis is widely used in radiologic research, confirming its fundamental role in assessing diagnostic performance. However, the ROC studies reported in Radiology were not always adequate to support clear and clinically relevant conclusions. © RSNA, 2009 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.2533081632/-/DC1 PMID:19864510

Operational Characteristics of an Accelerator Driven Fissile Solution System

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

Kimpland, Robert Herbert

Operational characteristics represent the set of responses that a nuclear system exhibits during normal operation. Operators rely on this behavior to assess the status of the system and to predict the consequences of off-normal events. These characteristics largely refer to the relationship between power and system operating conditions. The static and dynamic behavior of a chain-reacting system, operating at sufficient power, is primarily governed by reactivity effects. The science of reactor physics has identified and evaluated a number of such effects, including Doppler broadening and shifts in the thermal neutron spectrum. Often these reactivity effects are quantified in the formmore » of feedback coefficients that serve as coupling coefficients relating the neutron population and the physical mechanisms that drive reactivity effects, such as fissile material temperature and density changes. The operational characteristics of such nuclear systems usually manifest themselves when perturbations between system power (neutron population) and system operating conditions arise. Successful operation of such systems requires the establishment of steady equilibrium conditions. However, prior to obtaining the desired equilibrium (steady-state) conditions, an approach from zero-power (startup) must occur. This operational regime may possess certain limiting system conditions that must be maintained to achieve effective startup. Once steady-state is achieved, a key characteristic of this operational regime is the level of stability that the system possesses. Finally, a third operational regime, shutdown, may also possess limiting conditions of operation that must be maintained. This report documents the operational characteristics of a “generic” Accelerator Driven Fissile Solution (ADFS) system during the various operational regimes of startup, steady-state operation, and shutdown. Typical time-dependent behavior for each operational regime will be illustrated, and key system parameters, such as response times, will be quantified. A generalized linear systems analysis of steady-state operations will be performed to evaluate the level of stability of ADFS systems. This information should provide a basic understanding of typical ADFS system operational behavior, and facilitate the development of monitoring procedures and operator aids.« less

A review of hospital characteristics associated with improved performance.

PubMed

Brand, Caroline A; Barker, Anna L; Morello, Renata T; Vitale, Michael R; Evans, Sue M; Scott, Ian A; Stoelwinder, Johannes U; Cameron, Peter A

2012-10-01

The objective of this review was to critically appraise the literature relating to associations between high-level structural and operational hospital characteristics and improved performance. The Cochrane Library, MEDLINE (Ovid), CINAHL, proQuest and PsychINFO were searched for articles published between January 1996 and May 2010. Reference lists of included articles were reviewed and key journals were hand searched for relevant articles. and data extraction Studies were included if they were systematic reviews or meta-analyses, randomized controlled trials, controlled before and after studies or observational studies (cohort and cross-sectional) that were multicentre, comparative performance studies. Two reviewers independently extracted data, assigned grades of evidence according to the Australian National Health and Medical Research Council guidelines and critically appraised the included articles. Data synthesis Fifty-seven studies were reported within 12 systematic reviews and 47 observational articles. There was heterogeneity in use and definition of performance outcomes. Hospital characteristics investigated were environment (incentives, market characteristics), structure (network membership, ownership, teaching status, geographical setting, service size) and operational design (innovativeness, leadership, organizational culture, public reporting and patient safety practices, information technology systems and decision support, service activity and planning, workforce design, staff training and education). The strongest evidence for an association with overall performance was identified for computerized physician order entry systems. Some evidence supported the associations with workforce design, use of financial incentives, nursing leadership and hospital volume. There is limited, mainly low-quality evidence, supporting the associations between hospital characteristics and healthcare performance. Further characteristic-specific systematic reviews are indicated.

Study of IEMP Effects on IC Operational Amplifier Circuits

DTIC Science & Technology

1975-12-10

plasma focus to study their IEMP responses with and without superposition of TREE responses. The 30-kJ plasma focus device produced photons primarily in the 8- to 100-keV range with pulse widths typically in the range of 10 to 15 nsec. Pulses of electrons were also deposited on the external leads of the operational amplifiers to determine the characteristic responses. These units were operated in circuits with closed-loop gains ranging from 5 to 100. During direct irradiation of the operational amplifiers, it was found that the IEMP responses (caused

Characteristics of future air cargo demand and impact on aircraft development: A report on the Cargo/Logistic Airlift Systems Study (CLASS) project

NASA Technical Reports Server (NTRS)

Whitehead, A. H., Jr.

1978-01-01

Current domestic and international air cargo operations are studied and the characteristics of 1990 air cargo demand are postulated from surveys conducted at airports and with shippers, consignees, and freight forwarders as well as air, land, and ocean carriers. Simulation and route optimization programs are exercised to evaluate advanced aircraft concepts. The results show that proposed changes in the infrastructure and improved cargo loading efficiencies are as important enhancing the prospects of air cargo growth as is the advent of advanced freighter aircraft. Potential reductions in aircraft direct operating costs are estimated and related to future total revenue. Service and cost elasticities are established and utilized to estimate future potential tariff reductions that may be realized through direct and indirect operating cost reductions and economies of scale.

Study and characterization of a MEMS micromirror device

NASA Astrophysics Data System (ADS)

Furlong, Cosme; Pryputniewicz, Ryszard J.

2004-08-01

In this paper, advances in our study and characterization of a MEMS micromirror device are presented. The micromirror device, of 510 mm characteristic length, operates in a dynamic mode with a maximum displacement on the order of 10 mm along its principal optical axis and oscillation frequencies of up to 1.3 kHz. Developments are carried on by analytical, computational, and experimental methods. Analytical and computational nonlinear geometrical models are developed in order to determine the optimal loading-displacement operational characteristics of the micromirror. Due to the operational mode of the micromirror, the experimental characterization of its loading-displacement transfer function requires utilization of advanced optical metrology methods. Optoelectronic holography (OEH) methodologies based on multiple wavelengths that we are developing to perform such characterization are described. It is shown that the analytical, computational, and experimental approach is effective in our developments.

A Study of the Characteristics of Human-Pilot Control Response to Simulated Aircraft Lateral Motions

NASA Technical Reports Server (NTRS)

Cheatham, Donald C

1954-01-01

Report presents the results of studies made in an attempt to provide information on the control operations of the human pilot. These studies included an investigation of the ability of pilots to control simulated unstable yawing oscillations, a study of the basic characteristics of human-pilot control response, and a study to determine whether and to what extent pilot control response can be represented in an analytical form.

Effect of Background Pressure on the Plasma Oscillation Characteristics of the HiVHAc Hall Thruster

DTIC Science & Technology

2014-06-01

Hall thruster , a number of plasma diagnostics were implemented to study the effect of varying facility background pressure on thruster operation. These diagnostics characterized the thruster performance, the plume, and the plasma oscillations in the thruster. Thruster performance and plume characteristics as functions of background pressure were previously published. This paper will focus on changes in the plasma oscillation characteristics with changing background pressure. The diagnostics used to study plasma oscillations include a high-speed camera and a set of

Receiver operating characteristic (ROC) curves: review of methods with applications in diagnostic medicine

NASA Astrophysics Data System (ADS)

Obuchowski, Nancy A.; Bullen, Jennifer A.

2018-04-01

Receiver operating characteristic (ROC) analysis is a tool used to describe the discrimination accuracy of a diagnostic test or prediction model. While sensitivity and specificity are the basic metrics of accuracy, they have many limitations when characterizing test accuracy, particularly when comparing the accuracies of competing tests. In this article we review the basic study design features of ROC studies, illustrate sample size calculations, present statistical methods for measuring and comparing accuracy, and highlight commonly used ROC software. We include descriptions of multi-reader ROC study design and analysis, address frequently seen problems of verification and location bias, discuss clustered data, and provide strategies for testing endpoints in ROC studies. The methods are illustrated with a study of transmission ultrasound for diagnosing breast lesions.

The Study of the Phase Characteristics of Bragg Cells for Acousto-Optic Signal Processing

DTIC Science & Technology

1998-01-01

contractor will determine the relationship of phase characteristics between TeO2 and GaAs cells with their constructive and technical parameters. Design a...Braggcell TeO2 with minimal phase distortions operating near 100 MHz. Experimentally investigate the phase characteristics for a Bragg cell on TeO2 ...follows: The contractor will determine the relationship of phase characteristics between TeO2 and GaAs cells with their constructive and technical

14 CFR 23.253 - High speed characteristics.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false High speed characteristics. 23.253 Section... Requirements § 23.253 High speed characteristics. If a maximum operating speed VMO/MMO is established under § 23.1505(c), the following speed increase and recovery characteristics must be met: (a) Operating...

14 CFR 23.253 - High speed characteristics.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false High speed characteristics. 23.253 Section... Requirements § 23.253 High speed characteristics. If a maximum operating speed VMO/MMO is established under § 23.1505(c), the following speed increase and recovery characteristics must be met: (a) Operating...

Estimation of the Operating Characteristics when the Test Information of the Old Test is not Constant II: Simple Sum Procedure of the Conditional P.D.F. Approach/Normal Approach Method Using Three Subtests of the Old Test. Research Report 80-4.

ERIC Educational Resources Information Center

Samejima, Fumiko

The rationale behind the method of estimating the operating characteristics of discrete item responses when the test information of the Old Test is not constant was presented previously. In the present study, two subtests of the Old Test, i.e. Subtests 1, and 2, each of which has a different non-constant test information function, are used in…

Performance of alkaline battery cells used in emergency locator transmitters

NASA Technical Reports Server (NTRS)

Haynes, G. A.; Sokol, S.; Motley, W. R., III; Mcclelland, E. L.

1984-01-01

The characteristics of battery power supplies for emergency locator transmitters (ELT's) were investigated by testing alkaline zinc/manganese dioxide cells of the type typically used in ELT's. Cells from four manufacturers were tested. The cells were subjected to simulated environmental and load conditions representative of those required for survival and operation. Battery cell characteristics that may contribute to ELT malfunctions and limitations were evaluated. Experimental results from the battery cell study are discussed, and an evaluation of ELT performance while operating under a representative worst-case environmental condition is presented.

Risk factors and outcomes of in-hospital cardiac arrest following pediatric heart operations of varying complexity.

PubMed

Gupta, Punkaj; Rettiganti, Mallikarjuna; Jeffries, Howard E; Scanlon, Matthew C; Ghanayem, Nancy S; Daufeldt, Jennifer; Rice, Tom B; Wetzel, Randall C

2016-08-01

Multi center data regarding cardiac arrest in children undergoing heart operations of varying complexity are limited. Children <18 years undergoing heart surgery (with or without cardiopulmonary bypass) in the Virtual Pediatric Systems (VPS, LLC) Database (2009-2014) were included. Multivariable mixed logistic regression models were adjusted for patient's characteristics, surgical risk category (STS-EACTS Categories 1, 2, and 3 classified as "low" complexity and Categories 4 and 5 classified as "high" complexity), and hospital characteristics. Overall, 26,909 patients (62 centers) were included. Of these, 2.7% had cardiac arrest after cardiac surgery with an associated mortality of 31%. The prevalence of cardiac arrest was lower among patients undergoing low complexity operations (low complexity vs. high complexity: 1.7% vs. 5.9%). Unadjusted outcomes after cardiac arrest were significantly better among patients undergoing low complexity operations (mortality: 21.6% vs. 39.1%, good neurological outcomes: 78.7% vs. 71.6%). In adjusted models, odds of cardiac arrest were significantly lower among patients undergoing low complexity operations (OR: 0.55, 95% CI: 0.46-0.66). Adjusted models, however, showed no difference in mortality or neurological outcomes after cardiac arrest regardless of surgical complexity. Further, our results suggest that incidence of cardiac arrest and mortality after cardiac arrest are a function of patient characteristics, surgical risk category, and hospital characteristics. Presence of around the clock in-house attending level pediatric intensivist coverage was associated with lower incidence of post-operative cardiac arrest, and presence of a dedicated cardiac ICU was associated with lower mortality after cardiac arrest. This study suggests that the patients undergoing high complexity operations are a higher risk group with increased prevalence of post-operative cardiac arrest. These data further suggest that patients undergoing high complexity operations can be rescued after cardiac arrest with a high survival rate. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Characteristics of Orthopedic Publications in High-Impact General Medical Journals.

PubMed

Nwachukwu, Benedict U; Kahlenberg, Cynthia A; Lehman, Jason D; Lyman, Stephen; Marx, Robert G

2017-05-01

Orthopedic studies are occasionally published in high-impact general medical journals; these studies are often given high visibility and have significant potential to impact health care policy and inform clinical decision-making. The purpose of this review was to investigate the characteristics of operative orthopedic studies published in high-impact medical journals. The number of orthopedic studies published in high-impact medical journals is relatively low; however, these studies demonstrate methodological characteristics that may bias toward nonoperative treatment. Careful analysis and interpretation of orthopedic studies published in these journals is warranted. [Orthopedics. 2017; 40(3):e405-e412.]. Copyright 2017, SLACK Incorporated.

CHARACTERISTICS OF MERCURY DESORPTION FROM SORBENTS AT ELEVATED TEMPERATURES. (R822721C697)

EPA Science Inventory

This study investigated the dynamic desorption characteristics of mercury during the thermal treatment of mercury-loaded sorbents at elevated temperatures under fixed-bed operations. Experiments were carried out in a 25.4 mm ID quartz bed enclosed in an electric furnace. ...

CHARACTERISTICS OF MERCURY DESORPTION FROM SORBENTS AT ELEVATED TEMPERATURES. (R826694C697)

EPA Science Inventory

This study investigated the dynamic desorption characteristics of mercury during the thermal treatment of mercury-loaded sorbents at elevated temperatures under fixed-bed operations. Experiments were carried out in a 25.4 mm ID quartz bed enclosed in an electric furnace. ...

TOEFL from a Communicative Viewpoint on Language Proficiency: A Working Paper.

ERIC Educational Resources Information Center

Duran, Richard P.; And Others

The content characteristics of the Test of English as a Foreign Language (TOEFL) are examined from a communicative viewpoint, based on current theory in applied linguistics and language proficiency assessment. The study employed a four-part operational framework. The first component analyzed the communicative characteristics of a language…

Study of bituminous surface treatments in Virginia : Phase II, Summer, 1964 : Distribution characteristics of materials, effectiveness of one size aggregate, setting time.

DOT National Transportation Integrated Search

1970-01-01

Distribution Characteristics of Materials: Ten bituminous distributors and ten chip spreading operations were investigated the former by cotton pad, cup, and trough tests; the latter by measuring the distance covered by a truckload and by placing pan...

Mission roles for the solar electric propulsion stage with the space transportation system

NASA Technical Reports Server (NTRS)

1974-01-01

A briefing outline is presented of the mission roles for the solar electric propulsion stage (SEPS). Topics outlined include operational considerations and mission characteristics, trade studies and technology assessments influencing SEPS configuration definition, program support requirements, and development and operations cost estimates.

Performance of the PHOBOS silicon sensors

NASA Astrophysics Data System (ADS)

Decowski, M. P.; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Garcia, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hołyński, R.; Hofman, D. J.; Holzman, B.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Mülmenstädt, J.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Stephans, G. S. F.; Steinberg, P.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

2002-02-01

The PHOBOS detector is designed to study the physics of Au+Au collisions at the Relativistic Heavy Ion Collider. The detector is almost entirely made of silicon pad detectors and was fully operational during the first year of operation. The detector is described, and key performance characteristics are summarized.

14 CFR 33.51 - Operation test.

Code of Federal Regulations, 2012 CFR

2012-01-01

... STANDARDS: AIRCRAFT ENGINES Block Tests; Reciprocating Aircraft Engines § 33.51 Operation test. The... characteristics, starting, idling, acceleration, overspeeding, functioning of propeller and ignition, and any other operational characteristic of the engine. If the engine incorporates a multispeed supercharger...

14 CFR 33.51 - Operation test.

Code of Federal Regulations, 2011 CFR

2011-01-01

... STANDARDS: AIRCRAFT ENGINES Block Tests; Reciprocating Aircraft Engines § 33.51 Operation test. The... characteristics, starting, idling, acceleration, overspeeding, functioning of propeller and ignition, and any other operational characteristic of the engine. If the engine incorporates a multispeed supercharger...

High voltage insulation of bushing for HTS power equipment

NASA Astrophysics Data System (ADS)

Kim, Woo-Jin; Choi, Jae-Hyeong; Kim, Sang-Hyun

2012-12-01

For the operation of high temperature superconducting (HTS) power equipments, it is necessary to develop insulating materials and high voltage (HV) insulation technology at cryogenic temperature of bushing. Liquid nitrogen (LN2) is an attractive dielectric liquid. Also, the polymer insulating materials are expected to be used as solid materials such as glass fiber reinforced plastic (GFRP), polytetra-fluoroethylene (PTFE, Teflon), Silicon (Si) rubber, aromatic polyamide (Nomex), EPDM/Silicon alloy compound (EPDM/Si). In this paper, the surface flashover characteristics of various insulating materials in LN2 are studied. These results are studied at both AC and impulse voltage under a non-uniform field. The use of GFRP and Teflon as insulation body for HTS bushing should be much desirable. Especially, GFRP is excellent material not only surface flashover characteristics but also mechanical characteristics at cryogenic temperature. The surface flashover is most serious problem for the shed design in LN2 and operation of superconducting equipments.

Differential Weight Procedure of the Conditional P.D.F. Approach for Estimating the Operating Characteristics of Discrete Item Responses.

ERIC Educational Resources Information Center

Samejima, Fumiko

A method is proposed that increases the accuracies of estimation of the operating characteristics of discrete item responses, especially when the true operating characteristic is represented by a steep curve, and also at the lower and upper ends of the ability distribution where the estimation tends to be inaccurate because of the smaller number…

Users' demographic profile and quality attributes of bus services: The perspectives of users, operators and local authorities

NASA Astrophysics Data System (ADS)

Noh, Nur'Amirah Mhd.; Hamid, Ahmad Hilmy Abd

2017-10-01

Bus services that can help meet almost every bus user's needs are the goals of bus operators. Despite such an idealistic view, the operators themselves, users and even the local authorities have been found to hold different views about the quality of service that the bus should deliver. As the users i.e., customers are considered as important stakeholders, understanding their characteristics, profile and pattern is very crucial. To this end, the present study has attempted to gauge the perspectives of all the above-mentioned stakeholders. For the users, a customer satisfaction survey was employed to look into the relative influence of service attributes. In addition, surveys were also administered to bus operators and local authorities to study their perspectives in relation to this matter. 450 randomly selected respondents were surveyed. Identification of the service level was analyzed through the Likert scale whereas the perspectives of the operators and authorities were dealt with through mean value Analysis. Specifically, this study aims to identify the crucial attributes in determining the quality of the bus services. Findings of the study indicated that different attributes were selected by users, operators and authorities, which clearly enlightened the variations of the important attributes in determining the level of bus service quality. In its attempt to compare the service level attributes from three perspectives, this study has helped advance better improvement and strategies for the urban public bus operators and planners, in addition to the authorities in delivering user-friendly bus services by taking into account the local context, user profile and demographic characteristics.

Operating characteristics of depression and anxiety disorder phenotype dimensions and trait neuroticism: a theoretical examination of the fear and distress disorders from the Netherlands study of depression and anxiety.

PubMed

Tully, Phillip J; Wardenaar, Klaas J; Penninx, Brenda W J H

2015-03-15

The receiver operating characteristics (ROC) of anhedonic depression and anxious arousal to detect the distress- (major depression, dysthymia, generalized anxiety disorder) and fear-disorder clusters (i.e. panic disorder, agoraphobia, social phobia) have not been reported in a large sample. A sample of 2981 persons underwent structured psychiatric interview; n=652 were without lifetime depression and anxiety disorder history. Participants also completed a neuroticism scale (Revised NEO Five Factor Inventory [NEO-FFI]), and the 30-item short adaptation of the Mood and Anxiety Symptoms Questionnaire (MASQ-D30) measuring anhedonic depression, anxious arousal and general distress. Maximal sensitivity and specificity was determined by the Youden Index and the area-under-the-curve (AUC) in ROC analysis. A total of 2624 completed all measures (age M=42.4 years±13.1, 1760 females [67.1%]), including 1060 (40.4%) persons who met criteria for a distress-disorder, and 973 (37.1%) who met criteria for a fear-disorder. The general distress dimension provided the highest ROC values in the detection of the distress-disorders (AUC=.814, sensitivity=71.95%, specificity=76.34%, positive predictive value=67.33, negative predictive value=80.07). None of the measures provided suitable operating characteristics in the detection of the fear-disorders with specificity values <75%. Over sampling of depression and anxiety disorders may lead to inflated positive- and negative predictive values. The MASQ-D30 general distress dimension showed clinically suitable operating characteristics in the detection of distress-disorders. Neither neuroticism nor the MASQ-D30 dimensions provided suitable operating characteristics in the detection of the fear-disorders. Copyright © 2014 Elsevier B.V. All rights reserved.

Performance of the European System for Cardiac Operative Risk Evaluation II: a meta-analysis of 22 studies involving 145,592 cardiac surgery procedures.

PubMed

Guida, Pietro; Mastro, Florinda; Scrascia, Giuseppe; Whitlock, Richard; Paparella, Domenico

2014-12-01

A systematic review of the European System for Cardiac Operative Risk Evaluation (euroSCORE) II performance for prediction of operative mortality after cardiac surgery has not been performed. We conducted a meta-analysis of studies based on the predictive accuracy of the euroSCORE II. We searched the Embase and PubMed databases for all English-only articles reporting performance characteristics of the euroSCORE II. The area under the receiver operating characteristic curve, the observed/expected mortality ratio, and observed-expected mortality difference with their 95% confidence intervals were analyzed. Twenty-two articles were selected, including 145,592 procedures. Operative mortality occurred in 4293 (2.95%), whereas the expected events according to euroSCORE II were 4802 (3.30%). Meta-analysis of these studies provided an area under the receiver operating characteristic curve of 0.792 (95% confidence interval, 0.773-0.811), an estimated observed/expected ratio of 1.019 (95% confidence interval, 0.899-1.139), and observed-expected difference of 0.125 (95% confidence interval, -0.269 to 0.519). Statistical heterogeneity was detected among retrospective studies including less recent procedures. Subgroups analysis confirmed the robustness of combined estimates for isolated valve procedures and those combined with revascularization surgery. A significant overestimation of the euroSCORE II with an observed/expected ratio of 0.829 (95% confidence interval, 0.677-0.982) was observed in isolated coronary artery bypass grafting and a slight underestimation of predictions in high-risk patients (observed/expected ratio 1.253 and observed-expected difference 1.859). Despite the heterogeneity, the results from this meta-analysis show a good overall performance of the euroSCORE II in terms of discrimination and accuracy of model predictions for operative mortality. Validation of the euroSCORE II in prospective populations needs to be further studied for a continuous improvement of patients' risk stratification before cardiac surgery. Copyright © 2014 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

CFD modeling using PDF approach for investigating the flame length in rotary kilns

NASA Astrophysics Data System (ADS)

Elattar, H. F.; Specht, E.; Fouda, A.; Bin-Mahfouz, Abdullah S.

2016-12-01

Numerical simulations using computational fluid dynamics (CFD) are performed to investigate the flame length characteristics in rotary kilns using probability density function (PDF) approach. A commercial CFD package (ANSYS-Fluent) is employed for this objective. A 2-D axisymmetric model is applied to study the effect of both operating and geometric parameters of rotary kiln on the characteristics of the flame length. Three types of gaseous fuel are used in the present work; methane (CH4), carbon monoxide (CO) and biogas (50 % CH4 + 50 % CO2). Preliminary comparison study of 2-D modeling outputs of free jet flames with available experimental data is carried out to choose and validate the proper turbulence model for the present numerical simulations. The results showed that the excess air number, diameter of kiln air entrance, radiation modeling consideration and fuel type have remarkable effects on the flame length characteristics. Numerical correlations for the rotary kiln flame length are presented in terms of the studied kiln operating and geometric parameters within acceptable error.

Precision of Four Acoustic Bone Measurement Devices

NASA Technical Reports Server (NTRS)

Miller, Christopher; Feiveson, Alan H.; Shackelford, Linda; Rianon, Nahida; LeBlanc, Adrian

2000-01-01

Though many studies have quantified the precision of various acoustic bone measurement devices, it is difficult to directly compare the results among the studies, because they used disparate subject pools, did not specify the estimation methodology, or did not use consistent definitions for various precision characteristics. In this study, we used a repeated measures design protocol to directly determine the precision characteristics of four acoustic bone measurement devices: the Mechanical Response Tissue Analyzer (MRTA), the UBA-575+, the SoundScan 2000 (S2000), and the Sahara Ultrasound Done Analyzer. Ten men and ten women were scanned on all four devices by two different operators at five discrete time points: Week 1, Week 2, Week 3, Month 3 and Month 6. The percent coefficient of variation (%CV) and standardized coefficient of variation were computed for the following precision characteristics: interoperator effect, operator-subject interaction, short-term error variance, and long-term drift, The MRTA had high interoperator errors for its ulnar and tibial stiffness measures and a large long-term drift in its tibial stiffness measurement. The UBA-575+ exhibited large short-term error variances and long-term drift for all three of its measurements. The S2000's tibial speed of sound measurement showed a high short-term error variance and a significant operator-subject interaction but very good values ( < 1%) for the other precision characteristics. The Sahara seemed to have the best overall performance, but was hampered by a large %CV for short-term error variance in its broadband ultrasound attenuation measure.

Precision of Four Acoustic Bone Measurement Devices

NASA Technical Reports Server (NTRS)

Miller, Christopher; Rianon, Nahid; Feiveson, Alan; Shackelford, Linda; LeBlanc, Adrian

2000-01-01

Though many studies have quantified the precision of various acoustic bone measurement devices, it is difficult to directly compare the results among the studies, because they used disparate subject pools, did not specify the estimation methodology, or did not use consistent definitions for various precision characteristics. In this study, we used a repeated measures design protocol to directly determine the precision characteristics of four acoustic bone measurement devices: the Mechanical Response Tissue Analyzer (MRTA), the UBA-575+, the SoundScan 2000 (S2000), and the Sahara Ultrasound Bone Analyzer. Ten men and ten women were scanned on all four devices by two different operators at five discrete time points: Week 1, Week 2, Week 3, Month 3 and Month 6. The percent coefficient of variation (%CV) and standardized coefficient of variation were computed for the following precision characteristics: interoperator effect, operator-subject interaction, short-term error variance, and long-term drift. The MRTA had high interoperator errors for its ulnar and tibial stiffness measures and a large long-term drift in its tibial stiffness measurement. The UBA-575+ exhibited large short-term error variances and long-term drift for all three of its measurements. The S2000's tibial speed of sound measurement showed a high short-term error variance and a significant operator-subject interaction but very good values (less than 1%) for the other precision characteristics. The Sahara seemed to have the best overall performance, but was hampered by a large %CV for short-term error variance in its broadband ultrasound attenuation measure.

Corruption: Engineers are Victims, Perpetrators or Both?

PubMed

Pecujlija, M; Cosic, I; Nesic-Grubic, L; Drobnjak, S

2015-08-01

This study was conducted in Serbian companies on licensed engineers and in its first part included a total of 336 licensed engineers who voluntarily completed the questionnaires about their ethical orientation and attitudes toward corruption and in the second part 214 engineers who participated in the first survey, who voluntarily evaluated their company's business operations characteristics. This study has clearly shown that there is a direct significant influence of the engineer's ethical orientations and attitudes toward corruption on their evaluation of the characteristics of their respective companies regarding business operations. This research also clearly shows that only engineers with a strong deontological orientation, low ethical subjectivity, and strong readiness to fight corruption, low corruption acceptance and high awareness of corruption can successfully fight corruption, improve the business operations of their companies and make beneficial changes to society. Otherwise, they should be considered as corruption perpetrators, not just as its victims.

Solar power satellite system definition study. Volume 1, phase 1: Executive summary

NASA Technical Reports Server (NTRS)

1979-01-01

A systems definition study of the solar satellite system (SPS) is presented. The technical feasibility of solar power satellites based on forecasts of technical capability in the various applicable technologies is assessed. The performance, cost, operational characteristics, reliability, and the suitability of SPS's as power generators for typical commercial electricity grids are discussed. The uncertainties inherent in the system characteristics forecasts are assessed.

Learning across Lines. The Secret to More Efficient Factories.

ERIC Educational Resources Information Center

Lapre, Michael A.; Van Wassenhove, Luk N.

2002-01-01

Manufacturers' attempts to boost operating productivity rarely pay off and some do more harm than good. A study of a Belgian manufacturer illustrates characteristics that enhance productivity improvement: (1) production of process knowledge that is well understood and relevant and (2) transfer by combining conceptual and operational knowledge.…

Assessment of flying-quality criteria for air-breathing aerospacecraft

NASA Technical Reports Server (NTRS)

Mcruer, Duane T.; Myers, Thomas T.; Hoh, Roger H.; Ashkenas, Irving L.; Johnston, Donald E.

1992-01-01

A study of flying quality requirements for air breathing aerospacecraft gives special emphasis to the unusual operational requirements and characteristics of these aircraft, including operation at hypersonic speed. The report considers distinguishing characteristics of these vehicles, including dynamic deficiencies and their implications for control. Particular emphasis is given to the interaction of the airframe and propulsion system, and the requirements for dynamic systems integration. Past operational missions are reviewed to define tasks and maneuvers to be considered for this class of aircraft. Areas of special concern with respect to vehicle dynamics and control are identified. Experience with the space shuttle orbiter is reviewed with respect to flight control system mechanization and flight experience in approach and landing flying qualities for the National Aerospace Plane (NASP).

Improving the Reliability and Modal Stability of High Power 870 nm AlGaAs CSP Laser Diodes for Applications to Free Space Communication Systems

NASA Technical Reports Server (NTRS)

Connolly, J. C.; Alphonse, G. A.; Carlin, D. B.; Ettenberg, M.

1991-01-01

The operating characteristics (power-current, beam divergence, etc.) and reliability assessment of high-power CSP lasers is discussed. The emission wavelength of these lasers was optimized at 860 to 880 nm. The operational characteristics of a new laser, the inverse channel substrate planar (ICSP) laser, grown by metalorganic chemical vapor deposition (MOCVD), is discussed and the reliability assessment of this laser is reported. The highlights of this study include a reduction in the threshold current value for the laser to 15 mA and a degradation rate of less than 2 kW/hr for the lasers operating at 60 mW of peak output power.

Electrical and mechanical characteristics of fully transparent IZO thin-film transistors on stress-relieving bendable substrates

NASA Astrophysics Data System (ADS)

Park, Sukhyung; Cho, Kyoungah; Oh, Hyungon; Kim, Sangsig

2016-10-01

In this study, we report the electrical and mechanical characteristics of fully transparent indium zinc oxide (IZO) thin-film transistors (TFTs) fabricated on stress-relieving bendable substrates. An IZO TFT on a stress-relieving substrate can operate normally at a bending radius of 6 mm, while an IZO TFT on a normal plastic substrate fails to operate normally at a bending radius of 15 mm. A plastic island with high Young's modulus embedded on a soft elastomer layer with low Young's modulus plays the role of a stress-relieving substrate for the operation of the bent IZO TFT. The stress and strain distributions over the IZO TFT will be analyzed in detail in this paper.

Bootstrap-based procedures for inference in nonparametric receiver-operating characteristic curve regression analysis.

PubMed

Rodríguez-Álvarez, María Xosé; Roca-Pardiñas, Javier; Cadarso-Suárez, Carmen; Tahoces, Pablo G

2018-03-01

Prior to using a diagnostic test in a routine clinical setting, the rigorous evaluation of its diagnostic accuracy is essential. The receiver-operating characteristic curve is the measure of accuracy most widely used for continuous diagnostic tests. However, the possible impact of extra information about the patient (or even the environment) on diagnostic accuracy also needs to be assessed. In this paper, we focus on an estimator for the covariate-specific receiver-operating characteristic curve based on direct regression modelling and nonparametric smoothing techniques. This approach defines the class of generalised additive models for the receiver-operating characteristic curve. The main aim of the paper is to offer new inferential procedures for testing the effect of covariates on the conditional receiver-operating characteristic curve within the above-mentioned class. Specifically, two different bootstrap-based tests are suggested to check (a) the possible effect of continuous covariates on the receiver-operating characteristic curve and (b) the presence of factor-by-curve interaction terms. The validity of the proposed bootstrap-based procedures is supported by simulations. To facilitate the application of these new procedures in practice, an R-package, known as npROCRegression, is provided and briefly described. Finally, data derived from a computer-aided diagnostic system for the automatic detection of tumour masses in breast cancer is analysed.

Mechanical and hydraulic properties of sludge deposit on sludge drying reed beds (SDRBs): influence of sludge characteristics and loading rates.

PubMed

Vincent, Julie; Forquet, Nicolas; Molle, Pascal; Wisniewski, Christelle

2012-07-01

This work was designed to study the hydraulic properties of sludge deposit, focusing on the impact of operating conditions (i.e. loads and feeding frequencies) on air entrance (aerobic mineralization optimization) into the sludge deposit. The studied sludge deposits came from six 2m(2) pilot-scale SDRBs that had been in operation for 50 months with three different loads of 30, 50, and 70 kg of SSm(-2) y(-1). Two influents were assessed (i.e. activated sludge and septage) presenting different characteristics (i.e. pollutant contents, physical properties...). Two experimental approaches were employed based on establishing the water retention curve (capillary pressure versus volumetric water content) and the hydrotextural diagram to determine the hydraulic properties of sludge deposit. The study obtained valuable information for optimizing operating conditions, specifically for efficient management of loading frequency to optimize aerobic conditions within the sludge deposit. Copyright © 2012 Elsevier Ltd. All rights reserved.

14 CFR 133.41 - Flight characteristics requirements.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Flight characteristics requirements. 133.41... EXTERNAL-LOAD OPERATIONS Airworthiness Requirements § 133.41 Flight characteristics requirements. (a) The applicant must demonstrate to the Administrator, by performing the operational flight checks prescribed in...

14 CFR 133.41 - Flight characteristics requirements.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Flight characteristics requirements. 133.41... EXTERNAL-LOAD OPERATIONS Airworthiness Requirements § 133.41 Flight characteristics requirements. (a) The applicant must demonstrate to the Administrator, by performing the operational flight checks prescribed in...

14 CFR 133.41 - Flight characteristics requirements.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Flight characteristics requirements. 133.41... EXTERNAL-LOAD OPERATIONS Airworthiness Requirements § 133.41 Flight characteristics requirements. (a) The applicant must demonstrate to the Administrator, by performing the operational flight checks prescribed in...

49 CFR 234.205 - Operating characteristics of warning system apparatus.

Code of Federal Regulations, 2010 CFR

2010-10-01

... apparatus. 234.205 Section 234.205 Transportation Other Regulations Relating to Transportation (Continued... characteristics of warning system apparatus. Operating characteristics of electromagnetic, electronic, or electrical apparatus of each highway-rail crossing warning system shall be maintained in accordance with the...

49 CFR 234.205 - Operating characteristics of warning system apparatus.

Code of Federal Regulations, 2011 CFR

2011-10-01

... apparatus. 234.205 Section 234.205 Transportation Other Regulations Relating to Transportation (Continued... characteristics of warning system apparatus. Operating characteristics of electromagnetic, electronic, or electrical apparatus of each highway-rail crossing warning system shall be maintained in accordance with the...

Icing-Protection Requirements for Reciprocating-Engine Induction System

NASA Technical Reports Server (NTRS)

Coles, Willard D; Rollin, Vern G; Mulholland, Donald R

1950-01-01

Despite the development of relatively ice-free fuel-metering systems, the widespread use of alternate and heated-air intakes, and the use of alcohol for emergency de-icing, icing of aircraft-engine induction systems is a serious problem. Investigations have been made to study and to combat all phases of this icing problem. From these investigations, criterions for safe operation and for design of new induction systems have been established. The results were obtained from laboratory investigations of carburetor-supercharger combinations, wind-tunnel investigations of air scoops, multicylinder-engine studies, and flight investigations. Characteristics of three forms of ice, impact, throttling, and fuel evaporation were studied. The effects of several factors on the icing characteristics were also studied and included: (1) atmospheric conditions, (2) engine and air-scoop configurations, including light-airplane system, (3) type fuel used, and (4) operating variables, such as power condition, use of a manifold pressure regulator, mixture setting, carburetor heat, and water-alcohol injection. In addition, ice-detection methods were investigated and methods of preventing and removing induction-system ice were studied. Recommendations are given for design and operation with regard to induction-system design.

The performance of blood pressure-to-height ratio as a screening measure for identifying children and adolescents with hypertension: a meta-analysis.

PubMed

Ma, Chunming; Liu, Yue; Lu, Qiang; Lu, Na; Liu, Xiaoli; Tian, Yiming; Wang, Rui; Yin, Fuzai

2016-02-01

The blood pressure-to-height ratio (BPHR) has been shown to be an accurate index for screening hypertension in children and adolescents. The aim of the present study was to perform a meta-analysis to assess the performance of BPHR for the assessment of hypertension. Electronic and manual searches were performed to identify studies of the BPHR. After methodological quality assessment and data extraction, pooled estimates of the sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, area under the receiver operating characteristic curve and summary receiver operating characteristics were assessed systematically. The extent of heterogeneity for it was assessed. Six studies were identified for analysis. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio values of BPHR, for assessment of hypertension, were 96% [95% confidence interval (CI)=0.95-0.97], 90% (95% CI=0.90-0.91), 10.68 (95% CI=8.03-14.21), 0.04 (95% CI=0.03-0.07) and 247.82 (95% CI=114.50-536.34), respectively. The area under the receiver operating characteristic curve was 0.9472. The BPHR had higher diagnostic accuracies for identifying hypertension in children and adolescents.

Campaign Expenditures in School Levy Referenda and Their Relationship to Voter Approval: Evidence from Ohio, 2007-2010

ERIC Educational Resources Information Center

Ingle, William Kyle; Johnson, Paul Andrew; Givens, Matt Ryan; Rampelt, Jerry

2013-01-01

Using logistic regression, this study sought to understand the relationship between district characteristics, district finances, levy characteristics, and campaign expenditures with new operating levy outcomes. We found that employee benefits as a percentage of the district's budget were negatively associated with levy outcomes, while salaries…

Pilot/vehicle model analysis of visual and motion cue requirements in flight simulation. [helicopter hovering

NASA Technical Reports Server (NTRS)

Baron, S.; Lancraft, R.; Zacharias, G.

1980-01-01

The optimal control model (OCM) of the human operator is used to predict the effect of simulator characteristics on pilot performance and workload. The piloting task studied is helicopter hover. Among the simulator characteristics considered were (computer generated) visual display resolution, field of view and time delay.

Pump efficiency in solar-energy systems

NASA Technical Reports Server (NTRS)

1978-01-01

Study investigates characteristics of typical off-the-shelf pumping systems that might be used in solar systems. Report includes discussion of difficulties in predicting pump efficiency from manufacturers' data. Sample calculations are given. Peak efficiencies, flow-rate control, and noise levels are investigated. Review or theory of pumps types and operating characteristics is presented.

Characteristics of West Virginia loggers during economically difficult times

Treesearch

Ben Spong; Jinxing Wang; David Summerfield

2011-01-01

West Virginia licensed loggers have been surveyed over the years regarding their business, operational, and personal characteristics. An update of this study was completed in 2009 to illustrate the impacts of the current economic conditions on the forestry and forest products industries. Additionally, this survey will help demonstrate the preparedness of the logging...

Student Benefits from School Farm Activities as Perceived by Administrators and Instructors.

ERIC Educational Resources Information Center

Williams, David L.; McCarthy, David A.

1985-01-01

Describes a study designed to determine characteristics of school farms operated by vocational agriculture departments in four states, identify how the farms are utilized, identify personal and situational characteristics of school farm teachers and administrators, and identify benefits to students of the school farms as perceived by teachers and…

The clubhouse as an empowering setting.

PubMed

Mowbray, Carol T; Lewandowski, Lisa; Holter, Mark; Bybee, Deborah

2006-08-01

Attention to psychosocial rehabilitation (PSR) practice has expanded in recent years. However, social work research studies on PSR are not numerous. This study focuses on operational characteristics of clubhouses, a major PSR program model, and the organizational attributes (including resource levels) that predict the extent to which the clubhouse constitutes an empowering setting. The authors present data from a statewide sample of 30 clubhouses, annually serving nearly 4,000 consumers (adults with serious mental illnesses), based on interviews of clubhouse directors, on-site observations, and government information sources. Results indicate that users were predominantly male, white, and middle age; about one-third had a major functional disability. There were wide variations in member characteristics as well as in resource levels. In terms of empowerment, this sample of clubs averaged rather low levels of member involvement in governance and operations but seemed to provide members with opportunities and assistance in making their own decisions. The empowerment variables had different predictors, including client characteristics, urban-related characteristics, staffing, and resource levels. Implications for social work practice in PSR settings are discussed.

49 CFR 236.8 - Operating characteristics of electromagnetic, electronic, or electrical apparatus.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Operating characteristics of electromagnetic, electronic, or electrical apparatus. 236.8 Section 236.8 Transportation Other Regulations Relating to... characteristics of electromagnetic, electronic, or electrical apparatus. Signal apparatus, the functioning of...

49 CFR 236.8 - Operating characteristics of electromagnetic, electronic, or electrical apparatus.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Operating characteristics of electromagnetic, electronic, or electrical apparatus. 236.8 Section 236.8 Transportation Other Regulations Relating to... characteristics of electromagnetic, electronic, or electrical apparatus. Signal apparatus, the functioning of...

49 CFR 236.8 - Operating characteristics of electromagnetic, electronic, or electrical apparatus.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Operating characteristics of electromagnetic, electronic, or electrical apparatus. 236.8 Section 236.8 Transportation Other Regulations Relating to... characteristics of electromagnetic, electronic, or electrical apparatus. Signal apparatus, the functioning of...

49 CFR 236.8 - Operating characteristics of electromagnetic, electronic, or electrical apparatus.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Operating characteristics of electromagnetic, electronic, or electrical apparatus. 236.8 Section 236.8 Transportation Other Regulations Relating to... characteristics of electromagnetic, electronic, or electrical apparatus. Signal apparatus, the functioning of...

49 CFR 236.8 - Operating characteristics of electromagnetic, electronic, or electrical apparatus.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Operating characteristics of electromagnetic, electronic, or electrical apparatus. 236.8 Section 236.8 Transportation Other Regulations Relating to... characteristics of electromagnetic, electronic, or electrical apparatus. Signal apparatus, the functioning of...

Track train dynamics analysis and test program: Methodology development for the derailment safety analysis of six-axle locomotives

NASA Technical Reports Server (NTRS)

Marcotte, P. P.; Mathewson, K. J. R.

1982-01-01

The operational safety of six axle locomotives is analyzed. A locomotive model with corresponding data on suspension characteristics, a method of track defect characterization, and a method of characterizing operational safety are used. A user oriented software package was developed as part of the methodology and was used to study the effect (on operational safety) of various locomotive parameters and operational conditions such as speed, tractive effort, and track curvature. The operational safety of three different locomotive designs was investigated.

Operating and hydrodynamic characteristics of a reversed flow jet loop bioreactor (RFJLB) with ejector.

PubMed

Wagh, Sameer M; Koranne, Kishore V; Sonolikar, Ram L

2012-04-01

The hydrodynamic characteristics of RFJLB was studied with superficial liquid velocity (Ul), nozzle diameter (Dn) and nozzle height (Hn) in the range of 0.0293-0.094m/s, 17.4-22.0mm and 50-400mm, respectively. For Dn=17.4mm, Hn=50 and 200mm, with ejector mode and regular operating procedure i.e. simultaneous entry of gas with increasing liquid velocity, had limitation of not establishing the circulation loop. To overcome this limitation a modified operating procedure i.e. entry of gas after established liquid circulation loop is proposed. Also the comparison of gas holdups with ejector and injector mode proves the effectiveness of ejector mode and can eliminate the supply of compressed gas. Thus proper choice of Dn, Hn and also the operating procedure becomes necessary. Copyright © 2012 Elsevier Ltd. All rights reserved.

Photovoltaic array: Power conditioner interface characteristics

NASA Technical Reports Server (NTRS)

Gonzalez, C. C.; Hill, G. M.; Ross, R. G., Jr.

1982-01-01

The electrical output (power, current, and voltage) of flat plate solar arrays changes constantly, due primarily to changes in cell temperature and irradiance level. As a result, array loads such as dc-to-ac power conditioners must be capable of accommodating widely varying input levels while maintaining operation at or near the maximum power point of the array. The array operating characteristics and extreme output limits necessary for the systematic design of array load interfaces under a wide variety of climatic conditions are studied. A number of interface parameters are examined, including optimum operating voltage, voltage energy, maximum power and current limits, and maximum open circuit voltage. The effect of array degradation and I-V curve fill factor or the array power conditioner interface is also discussed. Results are presented as normalized ratios of power conditioner parameters to array parameters, making the results universally applicable to a wide variety of system sizes, sites, and operating modes.

Respirator Use Among US Farm Operators With Asthma: Results From the 2011 Farm and Ranch Safety Survey

PubMed Central

Casey, Megan L.; Mazurek, Jacek M.

2017-01-01

Objective The purpose of this study was to estimate the national prevalence of respirator use among farm operators with farm work–related asthma and factors associated with respirator use. Methods The authors examined the 2011 Farm and Ranch Safety Survey, a national survey collected from 11,210 actively farming farm operators in the United States. Adjusted prevalence ratios (aPORs) of respirator use were calculated by demographic characteristics, farm characteristics, asthma characteristics, and selected exposures and hazards. Results Among the estimated 2.2 million farm operators in 2011, 35.7% reported using a respirator in the past 12 months. Respirator use was significantly (P <.05) associated with age, marital status, sex, smoking status, farm value of sales, farm type, farm acreage, and geographic region. Operators who work with pesticides were 3.5 times more likely to use respirator than those who did not work with pesticides (P < .0001). Among those with current asthma, 60.8% of operators with farm work–related asthma used respirators compared with 44.4% of operators with non–farm work–related asthma (P = .03). Farm operators with farm work–related asthma who had an asthma attack at work were 11.3 times more likely to report respirator use than those who did not have an asthma attack at work (P = .03). Conclusions Personal protective equipment, including respirators, is an approach to reducing respiratory exposures in agricultural settings, in particular among those with farm work–related asthma. Education for respirator use and evaluation for respirator tolerance should be considered. PMID:28095135

Ground noise measurements during static and flyby operations of the Cessna 02-T turbine powered airplane

NASA Technical Reports Server (NTRS)

Hilton, D. A.; Henderson, H. R.; Lawton, B. W.

1975-01-01

The field noise measurements on the Cessna 02-T turbine powered propeller aircraft are presented. The objective of the study was to obtain the basic noise characteristics of the aircraft during static ground runs and flyover tests, to identify the sources of the noise, and to correlate the noises with the aircraft operating conditions. The results are presented in the form of a overall noise levels, radiation patterns, and frequency spectra. The noise characteristics of the turbine powered aircraft are compared with those of the reciprocating engine powered aircraft.

Computer modeling of heat pipe performance

NASA Technical Reports Server (NTRS)

Peterson, G. P.

1983-01-01

A parametric study of the defining equations which govern the steady state operational characteristics of the Grumman monogroove dual passage heat pipe is presented. These defining equations are combined to develop a mathematical model which describes and predicts the operational and performance capabilities of a specific heat pipe given the necessary physical characteristics and working fluid. Included is a brief review of the current literature, a discussion of the governing equations, and a description of both the mathematical and computer model. Final results of preliminary test runs of the model are presented and compared with experimental tests on actual prototypes.

Thermodynamic Analysis of Dual-Mode Scramjet Engine Operation and Performance

NASA Technical Reports Server (NTRS)

Riggins, David; Tacket, Regan; Taylor, Trent; Auslender, Aaron

2006-01-01

Recent analytical advances in understanding the performance continuum (the thermodynamic spectrum) for air-breathing engines based on fundamental second-law considerations have clarified scramjet and ramjet operation, performance, and characteristics. Second-law based analysis is extended specifically in this work to clarify and describe the performance characteristics for dual-mode scramjet operation in the mid-speed range of flight Mach 4 to 7. This is done by a fundamental investigation of the complex but predictable interplay between heat release and irreversibilities in such an engine; results demonstrate the flow and performance character of the dual mode regime and of dual mode transition behavior. Both analytical and computational (multi-dimensional CFD) studies of sample dual-mode flow-fields are performed in order to demonstrate the second-law capability and performance and operability issues. The impact of the dual-mode regime is found to be characterized by decreasing overall irreversibility with increasing heat release, within the operability limits of the system.

The influence of utility-interactive PV system characteristics to ac power networks

NASA Astrophysics Data System (ADS)

Takeda, Y.; Takigawa, K.; Kaminosono, H.

Two basic experimental photovoltaic (PV) systems have been built for the study of variation of power quality, aspects of safety, and technical problems. One system uses a line-commutated inverter, while the other system uses a self-commutated inverter. A description is presented of the operating and generating characteristics of the two systems. The systems were connected to an ac simulated network which simulates an actual power distribution system. Attention is given to power generation characteristics, the control characteristics, the harmonics characteristics, aspects of coordination with the power network, and questions regarding the reliability of photovoltaic modules.

Aerodynamics as a subway design parameter

NASA Technical Reports Server (NTRS)

Kurtz, D. W.

1976-01-01

A parametric sensitivity study has been performed on the system operational energy requirement in order to guide subway design strategy. Aerodynamics can play a dominant or trivial role, depending upon the system characteristics. Optimization of the aerodynamic parameters may not minimize the total operational energy. Isolation of the station box from the tunnel and reduction of the inertial power requirements pay the largest dividends in terms of the operational energy requirement.

Medium frequency propagation characteristics of different transmission lines in an underground coal mine

PubMed Central

Li, Jingcheng; Waynert, Joseph A.; Whisner, Bruce G.

2015-01-01

A medium frequency (MF) communication system operating in an underground coal mine couples its signals to a long conductor, which acts as an MF transmission line (TL) in a tunnel to permit communications among transceivers along the line. The TL is generally the longest signal path for the system, and its propagation characteristics will have a major impact on the performance of the MF communication system. In this study, the propagation characteristics of three types of MF TLs in two layouts—on the roof and on the floor of a coal mine tunnel—were obtained in an effort to understand the propagation characteristics of different TLs in different locations. The study confirmed a low MF signal loss on all of these TLs. The study also found that the TLs in different layouts had substantially different propagation characteristics. The propagation characteristics of these different TLs in different layouts are presented in the paper. PMID:26203349

Electro-Thermal Simulation Studies of SiC Junction Diodes Containing Screw Dislocations Under High Reverse-Bias Operation

NASA Technical Reports Server (NTRS)

Joshi, R. P.

2001-01-01

The objective of this work was to conduct a modeling study of SiC P-N junction diodes operating under high reverse biased conditions. Analytical models and numerical simulation capabilities were to be developed for self-consistent electro-thermal analysis of the diode current-voltage (I-V) characteristics. Data from GRC indicate that screw dislocations are unavoidable in large area SiC devices, and lead to changes in the SiC diode electrical response characteristics under high field conditions. For example, device instability and failures linked to internal current filamentation have been observed. The physical origin of these processes is not well understood, and quantitative projections of the electrical behavior under high field and temperature conditions are lacking. Thermal calculations for SiC devices have not been reported in the literature either. So estimates or projections of peak device temperatures and power limitations do not exist. This numerical study and simulation analysis was aimed at resolving some of the above issues. The following tasks were successfully accomplished: (1) Development of physically based models using one- and two-dimensional drift-diffusion theory for the transport behavior and I-V characteristics; (2) One- and two-dimensional heat flow to account for internal device heating. This led to calculations of the internal temperature profiles, which in turn, were used to update the electrical transport parameters for a self-consistent analysis. The temperature profiles and the peak values were thus obtainable for a given device operating condition; (3) Inclusion of traps assumed to model the presence of internal screw dislocations running along the longitudinal direction; (4) Predictions of the operating characteristics with and without heating as a function of applied bias with and without traps. Both one and two-dimensional cases were implemented; (5) Assessment of device stability based on the operating characteristics. The presence of internal non-uniformities, particularly filamentary structures, was probed and demonstrated; (6) Cause and physical origins of filamentary behavior and unstable I-V characteristics were made transparent; (7) It was demonstrated that diodes containing defects would be more prone to thermal breakdown associated with the temperature dependent decrease in the thermal conductivity; and (8) Finally, negative differential resistance (S-shaped NDR) which can potential lead to device instability and filamentary behavior was shown to occur for diodes containing a line of defects such as could be associated with a screw dislocation line.

Multichannel, Active Low-Pass Filters

NASA Technical Reports Server (NTRS)

Lev, James J.

1989-01-01

Multichannel integrated circuits cascaded to obtain matched characteristics. Gain and phase characteristics of channels of multichannel, multistage, active, low-pass filter matched by making filter of cascaded multichannel integrated-circuit operational amplifiers. Concept takes advantage of inherent equality of electrical characteristics of nominally-identical circuit elements made on same integrated-circuit chip. Characteristics of channels vary identically with changes in temperature. If additional matched channels needed, chips containing more than two operational amplifiers apiece (e.g., commercial quad operational amplifliers) used. Concept applicable to variety of equipment requiring matched gain and phase in multiple channels - radar, test instruments, communication circuits, and equipment for electronic countermeasures.

Transmission Technologies and Operational Characteristic Analysis of Hybrid UHV AC/DC Power Grids in China

NASA Astrophysics Data System (ADS)

Tian, Zhang; Yanfeng, Gong

2017-05-01

In order to solve the contradiction between demand and distribution range of primary energy resource, Ultra High Voltage (UHV) power grids should be developed rapidly to meet development of energy bases and accessing of large-scale renewable energy. This paper reviewed the latest research processes of AC/DC transmission technologies, summarized the characteristics of AC/DC power grids, concluded that China’s power grids certainly enter a new period of large -scale hybrid UHV AC/DC power grids and characteristics of “strong DC and weak AC” becomes increasingly pro minent; possible problems in operation of AC/DC power grids was discussed, and interaction or effect between AC/DC power grids was made an intensive study of; according to above problems in operation of power grids, preliminary scheme is summarized as fo llows: strengthening backbone structures, enhancing AC/DC transmission technologies, promoting protection measures of clean energ y accessing grids, and taking actions to solve stability problems of voltage and frequency etc. It’s valuable for making hybrid UHV AC/DC power grids adapt to operating mode of large power grids, thus guaranteeing security and stability of power system.

Individual Differences in Response to Automation: The Five Factor Model of Personality

ERIC Educational Resources Information Center

Szalma, James L.; Taylor, Grant S.

2011-01-01

This study examined the relationship of operator personality (Five Factor Model) and characteristics of the task and of adaptive automation (reliability and adaptiveness--whether the automation was well-matched to changes in task demand) to operator performance, workload, stress, and coping. This represents the first investigation of how the Five…

Operational and safety impacts of restriping inside lanes of urban multilane curbed roadways to 11 feet or less to create wider outside curb lanes for bicyclists.

DOT National Transportation Integrated Search

2011-09-30

This study analyzes the influence of several site characteristics on the operational behavior of motorists when passing bicyclists on wider outside through lanes. More than 2000 videotaped passing events were analyzed. Several measures of effectivene...

Variable Order and Distributed Order Fractional Operators

NASA Technical Reports Server (NTRS)

Lorenzo, Carl F.; Hartley, Tom T.

2002-01-01

Many physical processes appear to exhibit fractional order behavior that may vary with time or space. The continuum of order in the fractional calculus allows the order of the fractional operator to be considered as a variable. This paper develops the concept of variable and distributed order fractional operators. Definitions based on the Riemann-Liouville definitions are introduced and behavior of the operators is studied. Several time domain definitions that assign different arguments to the order q in the Riemann-Liouville definition are introduced. For each of these definitions various characteristics are determined. These include: time invariance of the operator, operator initialization, physical realization, linearity, operational transforms. and memory characteristics of the defining kernels. A measure (m2) for memory retentiveness of the order history is introduced. A generalized linear argument for the order q allows the concept of "tailored" variable order fractional operators whose a, memory may be chosen for a particular application. Memory retentiveness (m2) and order dynamic behavior are investigated and applications are shown. The concept of distributed order operators where the order of the time based operator depends on an additional independent (spatial) variable is also forwarded. Several definitions and their Laplace transforms are developed, analysis methods with these operators are demonstrated, and examples shown. Finally operators of multivariable and distributed order are defined in their various applications are outlined.

Radar-based alert system to operate a sewerage network: relevance and operational effectiveness after several years of use.

PubMed

Faure, D; Payrastre, O; Auchet, P

2005-01-01

Since January 2000, the sewerage network of a very urbanised catchment area in the Greater Nancy Urban Community has been operated according to the alarms generated in real time by a storm alert system using weather radar data. This alert system is based on an automatic identification of intense rain cells in the radar images. This paper presents the characteristics of this alert system and synthesises the main results of two complementary studies realised in 2002 in order to estimate the relevance and the operational effectiveness of the alert system. The first study consisted in an off-line analysis of almost 50,000 intense rain cells detected in four years of historical radar data. The second study was an analysis of the experience feedback after two years of operational use of this alert system. The results of these studies are discussed in function of the initial operational objectives.

Operating characteristics of HTS power supply for and improving temporal stability of coated conductor magnet in liquid helium

NASA Astrophysics Data System (ADS)

Park, D. K.; Kim, Y. J.; Yang, S. E.; Kwon, N. Y.; Lee, H. G.; Ko, T. K.

2009-10-01

High temperature superconducting (HTS) magnets have been studied for insert coils of high field nuclear magnetic resonance (NMR) magnets but the temporal stability required for NMR is hard to achieve due to low index value and high joint resistance. In this research, the HTS power supply with magnets using coated conductor (CC) was investigated and tested in helium cryogenic system. All joints were conducted by soldering after etching stabilizer of the CC to minimize joint resistance. The pumping rate was determined by current amplitude and timing sequential control of heaters and the electromagnet. Operating characteristics were analyzed to enhance charging efficiency and the feasibility of temporally stable CC magnet during persistent mode was studied.

Plasma gasification of municipal solid waste

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

Carter, G.W.; Tsangaris, A.V.

1995-12-31

Resorption Canada Limited (RCL) has conducted extensive operational testing with plasma technology in their plasma facility near Ottawa, Ontario, Canada to develop an environmentally friendly waste disposal process. Plasma technology, when utilized in a reactor vessel with the exclusion of oxygen, provides for the complete gasification of all combustibles in source materials with non-combustibles being converted to a non-hazardous slag. The energy and environmental characteristics of the plasma gasification of carbonaceous waste materials were studied over a period of eight years during which RCL completed extensive experimentation with MSW. A plasma processing system capable of processing 200--400 lbs/hr of MSWmore » was designed and built. The experimentation on MSW concentrated on establishing the optimum operating parameters and determining the energy and environmental characteristics at these operating parameters.« less

Operation and biasing for single device equivalent to CMOS

DOEpatents

Welch, James D.

2001-01-01

Disclosed are semiconductor devices including at least one junction which is rectifying whether the semiconductor is caused to be N or P-type, by the presence of field induced carriers. In particular, inverting and non-inverting gate voltage channel induced semiconductor single devices with operating characteristics similar to conventional multiple device CMOS systems, which can be operated as modulators, are disclosed as are a non-latching SCR and an approach to blocking parasitic currents. Operation of the gate voltage channel induced semiconductor single devices with operating characteristics similar to multiple device CMOS systems under typical bias schemes is described, and simple demonstrative five mask fabrication procedures for the inverting and non-inverting gate voltage channel induced semiconductor single devices with operating characteristics similar to multiple device CMOS systems are also presented.

An improved cellular automata model for train operation simulation with dynamic acceleration

NASA Astrophysics Data System (ADS)

Li, Wen-Jun; Nie, Lei

2018-03-01

Urban rail transit plays an important role in the urban public traffic because of its advantages of fast speed, large transport capacity, high safety, reliability and low pollution. This study proposes an improved cellular automaton (CA) model by considering the dynamic characteristic of the train acceleration to analyze the energy consumption and train running time. Constructing an effective model for calculating energy consumption to aid train operation improvement is the basis for studying and analyzing energy-saving measures for urban rail transit system operation.

Persistent hemifacial spasm after microvascular decompression: a risk assessment model.

PubMed

Shah, Aalap; Horowitz, Michael

2017-06-01

Microvascular decompression (MVD) for hemifacial spasm (HFS) provides resolution of disabling symptoms such as eyelid twitching and muscle contractions of the entire hemiface. The primary aim of this study was to evaluate the predictive value of patient demographics and spasm characteristics on long-term outcomes, with or without intraoperative lateral spread response (LSR) as an additional variable in a risk assessment model. A retrospective study was undertaken to evaluate the associations of pre-operative patient characteristics, as well as intraoperative LSR and need for a staged procedure on the presence of persistent or recurrent HFS at the time of hospital discharge and at follow-up. A risk assessment model was constructed with the inclusion of six clinically or statistically significant variables from the univariate analyses. A receiving operator characteristic curve was generated, and area under the curve was calculated to determine the strength of the predictive model. A risk assessment model was first created consisting of significant pre-operative variables (Model 1) (age >50, female gender, history of botulinum toxin use, platysma muscle involvement). This model demonstrated borderline predictive value for persistent spasm at discharge (AUC .60; p=.045) and fair predictive value at follow-up (AUC .75; p=.001). Intraoperative variables (e.g. LSR persistence) demonstrated little additive value (Model 2) (AUC .67). Patients with a higher risk score (three or greater) demonstrated greater odds of persistent HFS at the time of discharge (OR 1.5 [95%CI 1.16-1.97]; p=.035), as well as greater odds of persistent or recurrent spasm at the time of follow-up (OR 3.0 [95%CI 1.52-5.95]; p=.002) Conclusions: A risk assessment model consisting of pre-operative clinical characteristics is useful in prognosticating HFS persistence at follow-up.

Factors Influencing Family Migration from Appalachia. Summary of Research Series.

ERIC Educational Resources Information Center

Groves, Robert H.; McCormick, Robert W.

This study was designed to compare farm brothers who stayed in the rural areas of Ohio with urban brothers who migrated to large metropolitan areas of Ohio. The objectives were (1) to identify and compare selected characteristics of farm owners or operators who stayed on a farm in the Appalachian region of Ohio with selected characteristics of…

DOSIMETRIC CHARACTERISTICS OF GAMMA-TRON-2 (in Russian)

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

Krongauz, A.N.; Pavlova, T.G.; Frolova, A.V.

1963-01-01

Dosimetric characteristics of the Gammatron-2 during operation in a static regimen are presented. The air dose and the distribution of doses along the central ray of the beam and on the sides were determined. The protective properties of Gammatron-2 were studied. On the basis of the measurements, charts of isodoses were elaborated. (P.C.H.)

Understanding Schools as High-Reliability Organizations: An Exploratory Examination of Teachers' and School Leaders' Perceptions of Success

ERIC Educational Resources Information Center

Lorton, Juli A.; Bellamy, G. Thomas; Reece, Anne; Carlson, Jill

2013-01-01

Drawing on research on high-reliability organizations, this interviewbased qualitative case study employs four characteristics of such organizations as a lens for analyzing the operations of one very successful K-5 public school. Results suggest that the school had processes similar to those characteristic of high-reliability organizations: a…

Measures to increase airfield capacity by changing aircraft runway occupancy characteristics

NASA Technical Reports Server (NTRS)

Gosling, G. D.; Kanafani, A.; Rockaday, S. L. M.

1981-01-01

Airfield capacity and aircraft runway occupancy characteristics were studied. Factors that caused runway congestion and airfield crowding were identified. Several innovations designed to alleviate the congestion are discussed. Integrated landing management, the concept that the operation of the final approach and runway should be considered in concert, was identified as underlying all of the innovations.

Examining Herzberg's Theory: Improving Job Satisfaction among Non-Academic Employees at a University

ERIC Educational Resources Information Center

Smerek, Ryan E.; Peterson, Marvin

2007-01-01

This study reports the results of a survey of 2700 employees in business operations at a large public, research university. The analysis tests Herzberg et al.'s ("1959") well-known, duality theory of motivators and hygiene factors and the impact of personal characteristics and job characteristics on perceptions of the work environment and job…

Development of new structural health monitoring techniques

NASA Astrophysics Data System (ADS)

Fekrmandi, Hadi

During the past two decades, many researchers have developed methods for the detection of structural defects at the early stages to operate the aerospace vehicles safely and to reduce the operating costs. The Surface Response to Excitation (SuRE) method is one of these approaches developed at FIU to reduce the cost and size of the equipment. The SuRE method excites the surface at a series of frequencies and monitors the propagation characteristics of the generated waves. The amplitude of the waves reaching to any point on the surface varies with frequency; however, it remains consistent as long as the integrity and strain distribution on the part is consistent. These spectral characteristics change when cracks develop or the strain distribution changes. The SHM methods may be used for many applications, from the detection of loose screws to the monitoring of manufacturing operations. A scanning laser vibrometer was used in this study to investigate the characteristics of the spectral changes at different points on the parts. The study started with detecting a load on a plate and estimating its location. The modifications on the part with manufacturing operations were detected and the Part-Based Manufacturing Process Performance Monitoring (PbPPM) method was developed. Hardware was prepared to demonstrate the feasibility of the proposed methods in real time. Using low-cost piezoelectric elements and the non-contact scanning laser vibrometer successfully, the data was collected for the SuRE and PbPPM methods. Locational force, loose bolts and material loss could be easily detected by comparing the spectral characteristics of the arriving waves. On-line methods used fast computational methods for estimating the spectrum and detecting the changing operational conditions from sum of the squares of the variations. Neural networks classified the spectrums when the desktop -- DSP combination was used. The results demonstrated the feasibility of the SuRE and PbPPM methods.

Operating Characteristics of the Implicit Learning System Supporting Serial Interception Sequence Learning

ERIC Educational Resources Information Center

Sanchez, Daniel J.; Reber, Paul J.

2012-01-01

The memory system that supports implicit perceptual-motor sequence learning relies on brain regions that operate separately from the explicit, medial temporal lobe memory system. The implicit learning system therefore likely has distinct operating characteristics and information processing constraints. To attempt to identify the limits of the…

Space shuttle orbit maneuvering engine

NASA Technical Reports Server (NTRS)

Pauckert, R. P.

1975-01-01

Data on the performance, stability, and thermal characteristics of an OME operating with an alternate injector configuration and with alternate propellants was obtained. The design, manufacturing, and operating characteristics of an electroformed, regeneratively cooled thrust chamber were also derived. Subscale and full scale tests provide data relating to off-design and transient operation.

Study of quiet turbofan STOL aircraft for short-haul transportation. Volume 5: Economics

NASA Technical Reports Server (NTRS)

1973-01-01

The economic aspects of the STOL aircraft for short-haul air transportation are discussed. The study emphasized the potential market, the preferred operational concepts, the design characteristics, and the economic viability. Three central issues governing economic viability are as follows: (1) operator economics given the market, (2) the required transportation facilities, and (3) the external economic effects of a set of regional STOL transportation systems.

Numerical research of dynamic characteristics in tower solar cavity receiver based on step-change radiation flux

NASA Astrophysics Data System (ADS)

Chen, Zhengwei; Wang, Yueshe; Hao, Yun; Wang, Qizhi

2013-07-01

The solar cavity receiver is an important light-energy to thermal-energy convector in the tower solar thermal power plant system. The heat flux in the inner surface of the cavity will show the characteristics of non-continuous step change especially in non-normal and transient weather conditions, which may result in a continuous dynamic variation of the characteristic parameters. Therefore, the research of dynamic characteristics of the receiver plays a very important role in the operation and the control safely in solar cavity receiver system. In this paper, based on the non-continuous step change of radiation flux, a non-linear dynamic model is put forward to obtain the effects of the non-continuous step change radiation flux and step change feed water flow on the receiver performance by sequential modular approach. The subject investigated in our study is a 1MW solar power station constructed in Yanqing County, Beijing. This study has obtained the dynamic responses of the characteristic parameters in the cavity receiver, such as drum pressure, drum water level, main steam flow and main steam enthalpy under step change radiation flux. And the influence law of step-change feed water flow to the dynamic characteristics in the receiver also has been analyzed. The results have a reference value for the safe operation and the control in solar cavity receiver system.

Requirement for a standard language for test and ground operations

NASA Technical Reports Server (NTRS)

Medlock, J. R.

1971-01-01

The basic requirements for a standard test and checkout language applicable to all phases of the space shuttle test and ground operations are determined. The general characteristics outlined here represent the integration of selected ideas and concepts from operational elements within Kennedy Space Center (KSC) that represent diverse disciplines associated with space vehicle testing and launching operations. Special reference is made to two studies conducted in this area for KSC as authorized by the Advanced Development Element of the Office of Manned Space Flight (MSF). Information contained in reports from these studies have contributed significantly to the final selection of language features depicted in this technical report.

Approximation Model Building for Reliability & Maintainability Characteristics of Reusable Launch Vehicles

NASA Technical Reports Server (NTRS)

Unal, Resit; Morris, W. Douglas; White, Nancy H.; Lepsch, Roger A.; Brown, Richard W.

2000-01-01

This paper describes the development of parametric models for estimating operational reliability and maintainability (R&M) characteristics for reusable vehicle concepts, based on vehicle size and technology support level. A R&M analysis tool (RMAT) and response surface methods are utilized to build parametric approximation models for rapidly estimating operational R&M characteristics such as mission completion reliability. These models that approximate RMAT, can then be utilized for fast analysis of operational requirements, for lifecycle cost estimating and for multidisciplinary sign optimization.

Study of virgin olive oil clarification by settling under dynamic conditions.

PubMed

Gila, Abraham; Bejaoui, Mohamed Aymen; Beltrán, Gabriel; Aguilera, María Paz; Jiménez, Antonio

2018-04-16

Vertical centrifugation is the main method for virgin olive oil (VOO) clarification. However, in recent years, settling tanks are also being used to clarify the oils from decanters. They can operate under static or dynamic conditions. In this work, vertical centrifugation and settling under dynamic conditions for VOO clarification and their effects on VOO characteristics were compared. VOO quality parameters were not affected by the clarification systems studied. The vertical centrifugal separator (VCS) showed higher clarification efficiency, giving clarified oils with higher phenol content and better sensory characteristics. VOOs clarified by dynamic settling showed notable losses of phenols and worse sensory characteristics, since the tank purge system was not efficient, with most of the impurities remaining in the tanks. The VCS with minimal water addition is a quick operation with low water consumption and is a better option to produce VOOs of improved quality, especially in terms of longer shelf life and preservation of positive sensory notes. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

Characteristics of a 30-cm thruster operated with small hole accelerator grid ion optics

NASA Technical Reports Server (NTRS)

Vahrenkamp, R. P.

1976-01-01

Small hole accelerator grid ion optical systems have been tested as a possible means of improving 30-cm ion thruster performance. The effects of small hole grids on the critical aspects of thruster operation including discharge chamber performance, doubly-charged ion concentration, effluent beam characteristics, and plasma properties have been evaluated. In general, small hole accelerator grids are beneficial in improving thruster performance while maintaining low double ion ratios. However, extremely small accelerator aperture diameters tend to degrade beam divergence characteristics. A quantitative discussion of these advantages and disadvantages of small hole accelerator grids, as well as resulting variations in thruster operation characteristics, is presented.

User handbook for block IV silicon solar cell modules

NASA Technical Reports Server (NTRS)

Smokler, M. I.

1982-01-01

The essential electrical and mechanical characteristics of block 4 photovoltaic solar cell modules are described. Such module characteristics as power output, nominal operating voltage, current-voltage characteristics, nominal operating cell temperature, and dimensions are tabulated. The limits of the environmental and other stress tests to which the modules are subjected are briefly described.

The study of human higher mental functions as they relate to neurophysiological processes and personal characteristics

NASA Astrophysics Data System (ADS)

Runnova, Anastasiya; Zhuravlev, Maxim; Kulanin, Roman; Protasov, Pavel; Hramov, Alexander; Koronovskii, Alexey

2018-02-01

In this paper we study the correlation between the neurophysiological processes and personal characteristics arising in the processes of human higher mental functions. We find that the activity of the brain correlates with the results of psychological tests (according to the Cattell test). Experimental studies and math processing are described for operation design with the registration of human multi-channel EEG data in two phases (the processes of passive wakefulness (background) and special psychological testing (active phase)).

An experimental investigation of the effects of alarm processing and display on operator performance

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

O`Hara, J.; Brown, W.; Hallbert, B.

1998-03-01

This paper describes a research program sponsored by the US Nuclear Regulatory Commission to address the human factors engineering (HFE) aspects of nuclear power plant alarm systems. The overall objective of the program is to develop HFE review guidance for advanced alarm systems. As part of this program, guidance has been developed based on a broad base of technical and research literature. In the course of guidance development, aspects of alarm system design for which the technical basis was insufficient to support complete guidance development were identified. The primary purpose of the research reported in this paper was to evaluatemore » the effects of three of these alarm system design characteristics on operator performance in order to contribute to the understanding of potential safety issues and to provide data to support the development of design review guidance in these areas. Three alarm system design characteristics studied were (1) alarm processing (degree of alarm reduction), (2) alarm availability (dynamic prioritization and suppression), and (3) alarm display (a dedicated tile format, a mixed tile and message list format, and a format in which alarm information is integrated into the process displays). A secondary purpose was to provide confirmatory evidence of selected alarm system guidance developed in an earlier phase of the project. The alarm characteristics were combined into eight separate experimental conditions. Six, two-person crews of professional nuclear power plant operators participated in the study. Following training, each crew completed 16 test trials which consisted of two trials in each of the eight experimental conditions (one with a low-complexity scenario and one with a high-complexity scenario). Measures of process performance, operator task performance, situation awareness, and workload were obtained. In addition, operator opinions and evaluations of the alarm processing and display conditions were collected. No deficient performance was observed in any of the experimental conditions, providing confirmatory support for many design review guidelines. The operators identified numerous strengths and weaknesses associated with individual alarm design characteristics.« less

The electrical characteristics of the dielectric barrier discharges

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

Yehia, Ashraf, E-mail: yehia30161@yahoo.com; Department of Physics, Faculty of Science, Assiut University, Assiut 71516

2016-06-15

The electrical characteristics of the dielectric barrier discharges have been studied in this paper under different operating conditions. The dielectric barrier discharges were formed inside two reactors composed of electrodes in the shape of two parallel plates. The dielectric layers inside these reactors were pasted on the surface of one electrode only in the first reactor and on the surfaces of the two electrodes in the second reactor. The reactor under study has been fed by atmospheric air that flowed inside it with a constant rate at the normal temperature and pressure, in parallel with applying a sinusoidal ac voltagemore » between the electrodes of the reactor. The amount of the electric charge that flows from the reactors to the external circuit has been studied experimentally versus the ac peak voltage applied to them. An analytical model has been obtained for calculating the electrical characteristics of the dielectric barrier discharges that were formed inside the reactors during a complete cycle of the ac voltage. The results that were calculated by using this model have agreed well with the experimental results under the different operating conditions.« less

49 CFR Appendix B to Part 240 - Procedures for Submission and Approval of Locomotive Engineer Qualification Programs

Code of Federal Regulations, 2012 CFR

2012-10-01

... determining the qualifications of each person it permits or requires to operate a locomotive. In designing its...) for train control that are employed, the operational design characteristics of the track and equipment... completion of a course of study, or successful passage of a standardized testing program, the submission must...

49 CFR Appendix B to Part 240 - Procedures for Submission and Approval of Locomotive Engineer Qualification Programs

Code of Federal Regulations, 2013 CFR

2013-10-01

... determining the qualifications of each person it permits or requires to operate a locomotive. In designing its...) for train control that are employed, the operational design characteristics of the track and equipment... completion of a course of study, or successful passage of a standardized testing program, the submission must...

49 CFR Appendix B to Part 240 - Procedures for Submission and Approval of Locomotive Engineer Qualification Programs

Code of Federal Regulations, 2011 CFR

2011-10-01

... determining the qualifications of each person it permits or requires to operate a locomotive. In designing its...) for train control that are employed, the operational design characteristics of the track and equipment... completion of a course of study, or successful passage of a standardized testing program, the submission must...

49 CFR Appendix B to Part 240 - Procedures for Submission and Approval of Locomotive Engineer Qualification Programs

Code of Federal Regulations, 2010 CFR

2010-10-01

... determining the qualifications of each person it permits or requires to operate a locomotive. In designing its...) for train control that are employed, the operational design characteristics of the track and equipment... completion of a course of study, or successful passage of a standardized testing program, the submission must...

49 CFR Appendix B to Part 240 - Procedures for Submission and Approval of Locomotive Engineer Qualification Programs

Code of Federal Regulations, 2014 CFR

2014-10-01

... determining the qualifications of each person it permits or requires to operate a locomotive. In designing its...) for train control that are employed, the operational design characteristics of the track and equipment... completion of a course of study, or successful passage of a standardized testing program, the submission must...

The Cost of Quality Out-of-School-Time Programs

ERIC Educational Resources Information Center

Grossman, Jean Baldwin; Lind, Christianne; Hayes, Cheryl; McMaken, Jennifer; Gersick, Andrew

2009-01-01

Funders and program planners want to know: What does it cost to operate a high-quality after-school or summer program? This study answers that question, discovering that there is no "right" number. Cost varies substantially, depending on the characteristics of the participants, the goals of the program, who operates it and where it is located.…

Effects of intra-operative fluoroscopic 3D-imaging on peri-operative imaging strategy in calcaneal fracture surgery.

PubMed

Beerekamp, M S H; Backes, M; Schep, N W L; Ubbink, D T; Luitse, J S; Schepers, T; Goslings, J C

2017-12-01

Previous studies demonstrated that intra-operative fluoroscopic 3D-imaging (3D-imaging) in calcaneal fracture surgery is promising to prevent revision surgery and save costs. However, these studies limited their focus to corrections performed after 3D-imaging, thereby neglecting corrections after intra-operative fluoroscopic 2D-imaging (2D-imaging). The aim of this study was to assess the effects of additional 3D-imaging on intra-operative corrections, peri-operative imaging used, and patient-relevant outcomes compared to 2D-imaging alone. In this before-after study, data of adult patients who underwent open reduction and internal fixation (ORIF) of a calcaneal fracture between 2000 and 2014 in our level-I Trauma center were collected. 3D-imaging (BV Pulsera with 3D-RX, Philips Healthcare, Best, The Netherlands) was available as of 2007 at the surgeons' discretion. Patient and fracture characteristics, peri-operative imaging, intra-operative corrections and patient-relevant outcomes were collected from the hospital databases. Patients in whom additional 3D-imaging was applied were compared to those undergoing 2D-imaging alone. A total of 231 patients were included of whom 107 (46%) were operated with the use of 3D-imaging. No significant differences were found in baseline characteristics. The median duration of surgery was significantly longer when using 3D-imaging (2:08 vs. 1:54 h; p = 0.002). Corrections after additional 3D-imaging were performed in 53% of the patients. However, significantly fewer corrections were made after 2D-imaging when 3D-imaging was available (Risk difference (RD) -15%; 95% Confidence interval (CI) -29 to -2). Peri-operative imaging, besides intra-operative 3D-imaging, and patient-relevant outcomes were similar between groups. Intra-operative 3D-imaging provides additional information resulting in additional corrections. Moreover, 3D-imaging probably changed the surgeons' attitude to rely more on 3D-imaging, hence a 15%-decrease of corrections performed after 2D-imaging when 3D imaging was available. No substantiation for cost reduction was found through reduction in peri-operative imaging or in terms of improved patient-relevant outcomes.

Multi-band phase shifter design using modified slotline configuration

NASA Astrophysics Data System (ADS)

Kulandhaisamy, Indhumathi; Rajendran, Dinesh Babu; Kanagasabai, Malathi; Gurusamy, Gunasekaran; Moorthy, Balaji; George, Jithila V.; Lawrance, Livya

2017-01-01

In this paper, an analog multiband phase shifter using slotline configuration is proposed. To implement the design, a pair of modified Split Ring Resonator (SRR) is employed. The periodic property of SRR provides multiband characteristics, whether the coupling slot gives the phase variations over the bands. The operation is well explained with an equivalent circuit model and its characteristics have been studied both in simulation and measurement. The prototype operates in 1.77-2.16, 3.5-3.97, 5.08-5.33, 6.43-6.93, and 8.01-8.59 GHz frequency bands which can be utilized for GSM, GPS, WLAN, C-band, and X-band applications, respectively.

Bias stress instability of double-gate a-IGZO TFTs on polyimide substrate

NASA Astrophysics Data System (ADS)

Cho, Won-Ju; Ahn, Min-Ju

2017-09-01

In this study, flexible double-gate thin-film transistor (TFT)-based amorphous indium-galliumzinc- oxide (a-IGZO) was fabricated on a polyimide substrate. Double-gate operation with connected front and back gates was compared with a single-gate operation. As a result, the double-gate a- IGZO TFT exhibited enhanced electrical characteristics as well as improved long-term reliability. Under positive- and negative-bias temperature stress, the threshold voltage shift of the double-gate operation was much smaller than that of the single-gate operation.

Enlarging the operation range of a centrifugal compressor by cutting vanes based on CFD

NASA Astrophysics Data System (ADS)

Mo, J. T.; Gu, C. H.; Pan, X. H.; Y Zheng, S.

2013-12-01

Many centrifugal compressors are liable to insufficient operation range. The purpose of this paper is to enlarge the operation range of a centrifugal compressor used in turbocharger by cutting vanes. Some numerical works have been done based on CFD. The comparison of the calculated and measured results shows good agreement. The overall performance characteristics of the centrifugal compressor with different cutted vanes are observed and analyzed. The performance characteristic curves show that cutting vanes can increase the operation range by more than 50% with the loss of the highest efficiency limited in 1%. The flow fields are also shown in this paper and related explanations about the change of the performance characteristics curves are given. Shock wave is also detected in the simulation, and some related characteristics are summed up.

Sex and Social Influence: Does Sex Function as a Status Characteristic in Mixed-Sex Groups of Children?

ERIC Educational Resources Information Center

Lockheed, Marlaine E.; And Others

1983-01-01

The purpose of this study was to determine (1) whether sex operated as a diffuse status characteristic in mixed-sex groups of fourth- and fifth-grade children (n=168), and (2) whether an intervention based on expectation states theory would be successful in changing the status relationships within such groups. (PN)

Usefulness of cardiovascular magnetic resonance imaging to predict the need for intervention in patients with coarctation of the aorta.

PubMed

Muzzarelli, Stefano; Meadows, Alison Knauth; Ordovas, Karen Gomes; Higgins, Charles Bernard; Meadows, Jeffery Joshua

2012-03-15

Cardiovascular magnetic resonance (CMR) imaging can predict hemodynamically significant coarctation of the aorta (CoA) with a high degree of discrimination. However, the ability of CMR to predict important clinical outcomes in this patient population is unknown. Therefore, we sought to define the ability of CMR to predict the need for surgical or transcatheter intervention in patients with CoA. We retrospectively reviewed the data from 133 consecutive patients who had undergone CMR for the evaluation of known or suspected CoA. The characteristics of the CMR-derived variables predicting the need for surgical or transcatheter intervention for CoA within 1 year were determined through logistic regression analysis. Therapeutic aortic intervention was performed in 41 (31%) of the 133 patients during the study period. The indexed minimum aortic cross-sectional area was the strongest predictor of subsequent intervention (area under the receiver operating characteristic curve 0.975) followed by heart rate-corrected deceleration time in the descending aorta (area under the receiver operating characteristic curve 0.951), and the percentage of flow increase (area under the receiver operating characteristic curve 0.867). The combination of the indexed minimum aortic cross-sectional area and rate-corrected deceleration time in the descending aorta provided the best predictive model (area under the receiver operating characteristic curve 0.986). In conclusion, CMR findings can predict the need for subsequent intervention in CoA. These findings reinforce the "gate-keeper role" of CMR to cardiac catheterization by providing valuable diagnostic and powerful prognostic information and could guide additional treatment of patients with CoA with the final intent of reducing the number of diagnostic catheterizations in such patients. Copyright © 2012 Elsevier Inc. All rights reserved.

Comparison of chain sampling plans with single and double sampling plans

NASA Technical Reports Server (NTRS)

Stephens, K. S.; Dodge, H. F.

1976-01-01

The efficiency of chain sampling is examined through matching of operating characteristics (OC) curves of chain sampling plans (ChSP) with single and double sampling plans. In particular, the operating characteristics of some ChSP-0, 3 and 1, 3 as well as ChSP-0, 4 and 1, 4 are presented, where the number pairs represent the first and the second cumulative acceptance numbers. The fact that the ChSP procedure uses cumulative results from two or more samples and that the parameters can be varied to produce a wide variety of operating characteristics raises the question whether it may be possible for such plans to provide a given protection with less inspection than with single or double sampling plans. The operating ratio values reported illustrate the possibilities of matching single and double sampling plans with ChSP. It is shown that chain sampling plans provide improved efficiency over single and double sampling plans having substantially the same operating characteristics.

Up-and-down designs for phase I clinical trials

PubMed Central

Liu, Suyu; Cai, Chunyan; Ning, Jing

2014-01-01

Various up-and-down designs have been proposed to improve the operating characteristics of the traditional “3+3” design, but they have been of limited use in practice. A major impediment to the adoption of the improved up-and-down designs is a lack of general guidance and a comprehensive assessment of the operating characteristics of these designs under practical clinical settings. To fill this gap, we review six up-and-down designs: the “3+3” design, accelerated titration design, biased coin design, k-in-a-row design, group up-and-down design and cumulative group up-and-down design. We conduct comprehensive simulation studies to evaluate their operating characteristics under various practical settings, and compare their performance to a theoretical optimal bound of nonparametric designs. The results show that the cumulative group up-and-down design has the best overall performance in terms of selecting the maximum tolerated dose (MTD), assigning patients to the MTD and patient safety. Its performance is generally close to the upper bound of nonparametric designs, but improvement seems possible in some cases. PMID:23856381

Simulator study of flight characteristics of several large, dissimilar, cargo transport airplanes during approach and landing

NASA Technical Reports Server (NTRS)

Grantham, W. D.; Smith, P. M.; Deal, P. L.; Neely, W. R., Jr.

1984-01-01

A six-degree-of-freedom, ground based simulator study is conducted to evaluate the low-speed flight characteristics of four dissimilar cargo transport airplanes. These characteristics are compared with those of a large, present-day (reference) transport configuration similar to the Lockheed C-5A airplane. The four very large transport concepts evaluated consist of single-fuselage, twin-fuselage, triple-fuselage, and span-loader configurations. The primary piloting task is the approach and landing operation. The results of his study indicate that all four concepts evaluated have unsatisfactory longitudinal and lateral directional low speed flight characteristics and that considerable stability and control augmentation would be required to improve these characteristics (handling qualities) to a satisfactory level. Through the use of rate command/attitude hold augmentation in the pitch and roll axes, and the use of several turn-coordination features, the handling qualities of all four large transports simulated are improved appreciably.

Identification of cutoff points for Homeostatic Model Assessment for Insulin Resistance index in adolescents: systematic review

PubMed Central

de Andrade, Maria Izabel Siqueira; Oliveira, Juliana Souza; Leal, Vanessa Sá; da Lima, Niedja Maria Silva; Costa, Emília Chagas; de Aquino, Nathalia Barbosa; de Lira, Pedro Israel Cabral

2016-01-01

Abstract Objective: To identify cutoff points of the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) index established for adolescents and discuss their applicability for the diagnosis of insulin resistance in Brazilian adolescents. Data source: A systematic review was performed in the PubMed, Lilacs and SciELO databases, using the following descriptors: "adolescents", "insulin resistance" and "Receiver Operating Characteristics Curve". Original articles carried out with adolescents published between 2005 and 2015 in Portuguese, English or Spanish languages, which included the statistical analysis using Receiver Operating Characteristics Curve to determine the index cutoff (HOMA-IR) were included. Data synthesis: A total of 184 articles were identified and after the study phases were applied, seven articles were selected for the review. All selected studies established their cutoffs using a Receiver Operating Characteristics Curve, with the lowest observed cutoff of 1.65 for girls and 1.95 for boys and the highest of 3.82 for girls and 5.22 for boys. Of the studies analyzed, one proposed external validity, recommending the use of the HOMA-IR cutoff>2.5 for both genders. Conclusions: The HOMA-IR index constitutes a reliable method for the detection of insulin resistance in adolescents, as long as it uses cutoffs that are more adequate for the reality of the study population, allowing early diagnosis of insulin resistance and enabling multidisciplinary interventions aiming at health promotion of this population. PMID:26559605

Engineering and organizational solutions for improvement of engineering and economic characteristics of the TPE-216 boilers equipped with MV-3300/800/490 pulverizing fans

NASA Astrophysics Data System (ADS)

Kirillov, M. V.; Safronov, P. G.

2014-07-01

Efficiency of coal-fired boilers is determined in many respects by optimal operation of the coal-pulverizing plants that are increasingly frequently equipped with pulverizing fans. By an example of retrofitted MV-3300/800/490 pulverizing fans, the effects of different factors on the performance and economic efficiency of the coal-pulverizing plants are analyzed. The experience gained in retrofitting MV-3300/800/490 pulverizing fans by introducing the three-crusher operation mode of a TPE-216 boiler employing the internal recirculation and a blading device in the classifier was also studied. Optimization of the boiler's operation mode was made when switching over from the four-crusher to the three-crusher mode, which considerably improved the engineering and economic characteristics.

Spectrally resolved modal characteristics of leaky-wave-coupled quantum cascade phase-locked laser arrays

NASA Astrophysics Data System (ADS)

Sigler, Chris; Gibson, Ricky; Boyle, Colin; Kirch, Jeremy D.; Lindberg, Donald; Earles, Thomas; Botez, Dan; Mawst, Luke J.; Bedford, Robert

2018-01-01

The modal characteristics of nonresonant five-element phase-locked arrays of 4.7-μm emitting quantum cascade lasers (QCLs) have been studied using spectrally resolved near- and far-field measurements and correlated with results of device simulation. Devices are fabricated by a two-step metal-organic chemical vapor deposition process and operate predominantly in an in-phase array mode near threshold, although become multimode at higher drive levels. The wide spectral bandwidth of the QCL's core region is found to be a factor in promoting multispatial-mode operation at high drive levels above threshold. An optimized resonant-array design is identified to allow sole in-phase array-mode operation to high drive levels above threshold, and indicates that for phase-locked laser arrays full spatial coherence to high output powers does not require full temporal coherence.

Optimizing operating parameters of a honeycomb zeolite rotor concentrator for processing TFT-LCD volatile organic compounds with competitive adsorption characteristics.

PubMed

Lin, Yu-Chih; Chang, Feng-Tang

2009-05-30

In this study, we attempted to enhance the removal efficiency of a honeycomb zeolite rotor concentrator (HZRC), operated at optimal parameters, for processing TFT-LCD volatile organic compounds (VOCs) with competitive adsorption characteristics. The results indicated that when the HZRC processed a VOCs stream of mixed compounds, compounds with a high boiling point take precedence in the adsorption process. In addition, existing compounds with a low boiling point adsorbed onto the HZRC were also displaced by the high-boiling-point compounds. In order to achieve optimal operating parameters for high VOCs removal efficiency, results suggested controlling the inlet velocity to <1.5m/s, reducing the concentration ratio to 8 times, increasing the desorption temperature to 200-225 degrees C, and setting the rotation speed to 6.5rpm.

Spectrophotometric Method for Differentiation of Human Skin Melanoma. II. Diagnostic Characteristics

NASA Astrophysics Data System (ADS)

Petruk, V. G.; Ivanov, A. P.; Kvaternyuk, S. M.; Barunb, V. V.

2016-05-01

Experimental data on the spectral dependences of the optical diffuse reflection coefficient for skin from different people with melanoma or nevus are presented in the form of the probability density of the diffuse reflection coefficient for the corresponding pigmented lesions. We propose a noninvasive technique for differentiating between malignant and benign tumors, based on measuring the diffuse reflection coefficient for a specific patient and comparing the value obtained with a pre-set threshold. If the experimental result is below the threshold, then it is concluded that the person has melanoma; otherwise, no melanoma is present. As an example, we consider the wavelength 870 nm. We determine the risk of malignant transformation of a nevus (its transition to melanoma) for different measured diffuse reflection coefficients. We have studied the errors in the method, its operating characteristics and probability characteristics as the threshold diffuse reflection coefficient is varied. We find that the diagnostic confidence, sensitivity, specificity, and effectiveness (accuracy) parameters are maximum (>0.82) for a threshold of 0.45-0.47. The operating characteristics for the proposed technique exceed the corresponding parameters for other familiar optical approaches to melanoma diagnosis. Its distinguishing feature is operation at only one wavelength, and consequently implementation of the experimental technique is simplified and made less expensive.

7 CFR 42.142 - Curve for obtaining Operating Characteristic (OC) curve information for skip lot sampling and...

Code of Federal Regulations, 2010 CFR

2010-01-01

... the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... CONDITION OF FOOD CONTAINERS Miscellaneous § 42.142 Curve for obtaining Operating Characteristic (OC) curve...

A cross-sectional study of elderly Asian and European women with primary operable breast cancer aged 70 and older. Are there differences?

PubMed

Tea, Muy-Kheng M; Tang, Lichen; Di, Gen-Hong; Muin, Dana; Steurer, Stefan; Delancey, James W; Shao, Zhi-Ming; Singer, Christian F

2012-11-01

Breast cancer (BC) is becoming a disease of the elderly. Additionally, BC-incidence is rising in Asia. The aim of this study was to explore clinico-pathological characteristics and differences of breast cancer in elderly Asian/Han-Chinese compared to Caucasian/Austrian women. A total number of 630 consecutive primary operable, unilateral breast cancer cases, 70 years and older, were analyzed. Histo-pathological findings and biological characteristics of 198 Caucasian/Austrian were compared with 432 Asian/Han-Chinese. Pearson's chi-square test was used to assess differences in the analyzed populations. A significantly higher rate of triple-negative BC (p=0.027) was diagnosed among the Chinese geriatric population. More estrogen-receptor positive BC was detected in the Caucasian study group (p<0.001). No statistically significant differences were detected based on tumor size, axillary lymph-node status, nor HER2-receptor expression. This study will help us gain additional ethnic-specific insight into the biological characteristics of breast cancer in the elderly Caucasian/Austrian and Asian/Han-Chinese populations. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Future of Mechatronics and Human

NASA Astrophysics Data System (ADS)

Harashima, Fumio; Suzuki, Satoshi

This paper mentions circumstance of mechatronics that sustain our human society, and introduces HAM(Human Adaptive Mechatronics)-project as one of research projects to create new human-machine system. The key point of HAM is skill, and analysis of skill and establishment of assist method to enhance total performance of human-machine system are main research concerns. As study of skill is an elucidation of human itself, analyses of human higher function are significant. In this paper, after surveying researches of human brain functions, an experimental analysis of human characteristic in machine operation is shown as one example of our research activities. We used hovercraft simulator as verification system including observation, voluntary motion control and machine operation that are needed to general machine operation. Process and factors to become skilled were investigated by identification of human control characteristics with measurement of the operator's line-of sight. It was confirmed that early switching of sub-controllers / reference signals in human and enhancement of space perception are significant.

Research on breakdown characteristics of converter transformer oil-paper insulation under compound electric field in alpine region

NASA Astrophysics Data System (ADS)

Xu, C.; Gao, Z. W.; Lan, S.; Guo, H. X.; Gong, M. C.

2018-01-01

In the paper, existing research and operating experience was summarized. On the basis, the particularity of oil-paper insulation operation condition for converter transformer was combined for studying the influence of temperature on oil-paper insulation field intensity distribution of converter transformers under different AC contents within wide temperature scope (-40°C∼105°C). The law of temperature gradients on space charge accumulation was analyzed. The breakdown or flashover characteristics of typical oil-paper compound insulation structure under the action of DC, AC and AC-DC superposition voltage at different temperatures were explored. The design principles of converter transformer oil-paper insulation structures in alpine region was proposed. The principle was adjusted and optimized properly according to the operation temperature scope and withstood AC-DC proportion. The reliability of transformer operation was improved on the one hand, and the insulating medium can be rationally utilized for reducing the manufacturing cost of the transformer on the other hand.

Space nuclear power applied to electric propulsion

NASA Technical Reports Server (NTRS)

Vicente, F. A.; Karras, T.; Darooka, D.; Isenberg, L.

1989-01-01

Space reactor power systems with characteristics ideal for advanced spacecraft systems applications are discussed. These characteristics are: high power-to-weight ratio (15 to 33 W/kg); high volume density (high ballistic coefficient); no preferential orientation in orbit; long operational life; high reliability; and total launch and operational safety. These characteristics allow the use of electric propulsion to raise spacecraft from low earth parking orbits to operational orbits, greatly increasing the useful orbit payload for a given launch vehicle by eliminating the need for a separation injection stage. A proposed demonstration mission is described.

Estimation of the Operating Characteristics when the Test Information of the Old Test is not Constant. I. Rationale.

DTIC Science & Technology

1980-06-16

AO-AOB 075 TENNESSEE UNIV KNOXVILLE DIEPT OF PSYCHOLOGY F/G 12/1 AoI FSTIMATION OF THE OPERATING CHARACTERISTICS WHEM THE TEST INFOR--ETCIUI ’JUN... testing . Applied Psychological Measurement, 1, 1977, pages 2 33 -24 7 (a). [121 Samejima, F. Applications of graded response models: The promise of the... PSYCHOLOGY F/S 12/1 FSTIMATION OF THE OPERATING CHARACTERISTICS WHEP- THE TEST INFOR- ETC(U) JUN GO F SAMEJIMA N00014-77-C-0360 UNCLASSIFIED RR-80-2 NL

Effects of Injection Scheme on Rotating Detonation Engine Operation

NASA Astrophysics Data System (ADS)

Chacon, Fabian; Duvall, James; Gamba, Mirko

2017-11-01

In this work, we experimentally investigate the operation and performance characteristics of a rotating detonation engine (RDE) operated with different fuel injection schemes and operating conditions. In particular, we investigate the detonation and operation characteristics produced with an axial flow injector configuration and semi-impinging injector configurations. These are compared to the characteristics produced with a canonical radial injection system (AFRL injector). Each type produces a different flowfield and mixture distribution, leading to a different detonation initiation, injector dynamic response, and combustor pressure rise. By using a combination of diagnostics, we quantify the pressure loses and gains in the system, the ability to maintain detonation over a range of operating points, and the coupling between the detonation and the air/fuel feed lines. We particularly focus on how this coupling affects both the stability and the performance of the detonation wave. This work is supported by the DOE/UTSR program under project DE-FE0025315.

Study of quiet turbofan STOL aircraft for short haul transportation

NASA Technical Reports Server (NTRS)

Higgins, T. P.; Stout, E. G.; Sweet, H. S.

1973-01-01

Conceptual designs of Quiet Turbofan STOL Short-Haul Transport Aircraft for the mid-1980 time period are developed and analyzed to determine their technical, operational, and economic feasibility. A matrix of aircraft using various high-lift systems and design parameters are considered. Variations in aircraft characteristics, airport geometry and location, and operational techniques are analyzed systematically to determine their effects on the market, operating economics, and community acceptance. In these studies, the total systems approach is considered to be critically important in analyzing the potential of STOL aircraft to reduce noise pollution and alleviate the increasing air corridor and airport congestion.

Two dimensional eye tracking: Sampling rate of forcing function

NASA Technical Reports Server (NTRS)

Hornseth, J. P.; Monk, D. L.; Porterfield, J. L.; Mcmurry, R. L.

1978-01-01

A study was conducted to determine the minimum update rate of a forcing function display required for the operator to approximate the tracking performance obtained on a continuous display. In this study, frequency analysis was used to determine whether there was an associated change in the transfer function characteristics of the operator. It was expected that as the forcing function display update rate was reduced, from 120 to 15 samples per second, the operator's response to the high frequency components of the forcing function would show a decrease in gain, an increase in phase lag, and a decrease in coherence.

SU-E-I-85: Exploring the 18F-Fluorodeoxyglucose PET Characteristics in Staging of Esophageal Squamous Cell Carcinoma

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

Ma, C; Yin, Y

2014-06-01

Purpose: The aim of this study was to explore the characteristics derived from 18F-fluorodeoxyglucose (18F-FDG) PET image and assess its capacity in staging of esophageal squamous cell carcinoma (ESCC). Methods: 26 patients with newly diagnosed ESCC who underwent 18F-FDG PET scan were included in this study. Different image-derived indices including the standardized uptake value (SUV), gross tumor length, texture features and shape feature were considered. Taken the histopathologic examination as the gold standard, the extracted capacities of indices in staging of ESCC were assessed by Kruskal-Wallis test and Mann-Whitney test. Specificity and sensitivity for each of the studied parameters weremore » derived using receiver-operating characteristic curves. Results: 18F-FDG SUVmax and SUVmean showed statistically significant capability in AJCC and TNM stages. Texture features such as ENT and CORR were significant factors for N stages(p=0.040, p=0.029). Both FDG PET Longitudinal length and shape feature Eccentricity (EC) (p≤0.010) provided powerful stratification in the primary ESCC AJCC and TNM stages than SUV and texture features. Receiver-operating-characteristic curve analysis showed that tumor textural analysis can capability M stages with higher sensitivity than SUV measurement but lower in T and N stages. Conclusion: The 18F-FDG image-derived characteristics of SUV, textural features and shape feature allow for good stratification AJCC and TNM stage in ESCC patients.« less

Current food safety management systems in fish-exporting companies require further improvements to adequately cope with contextual pressure: case study.

PubMed

Onjong, Hillary Adawo; Wangoh, John; Njage, Patrick Murigu Kamau

2014-10-01

Fish-processing plants still face food safety (FS) challenges worldwide despite the existence of several quality assurance standards and food safety management systems/s (FSMSs). This study assessed performance of FSMS in fish exporting sector considering pressure from the context in which they operate. A FSMS diagnostic tool with checklist was used to assess the context, FSMS, and FS output in 9 Kenyan fish exporting companies. Majority (67%) companies operated at moderate- to high-risk context but with an average performance in control and assurance activities. This situation could be insufficient to deal with ambiguity, uncertainty, and vulnerability issues in the context characteristics. Contextual risk posed by product characteristics (nature of raw materials) and chain environment characteristics was high. Risk posed by the chain environment characteristics, low power in supplier relationships, and low degree of authority in customer relationships was high. Lack of authority in relationship with suppliers would lead to high raw material risk situation. Even though cooling facilities, a key control activity, was at an advanced level, there was inadequate packaging intervention equipment which coupled with inadequate physical intervention equipment could lead to further weakened FSMS performance. For the fish companies to improve their FSMS to higher level and enhance predictability, they should base their FSMS on scientific information sources, historical results, and own experimental trials in their preventive, intervention, and monitoring systems. Specific suggestions are derived for improvements toward higher FSMS activity levels or lower risk levels in context characteristics. Weak areas in performance of control and assurance activities in export fish-processing sector already implementing current quality assurance guidelines and standards were studied taking into consideration contextual pressure wherein the companies operate. Important mitigation measures toward improved contextual risk, core assurance, and control activities irrespective of applied food safety management systems in fish industries were suggested. © 2014 Institute of Food Technologists®

A Technique for the Assessment of Flight Operability Characteristics of Human Rated Spacecraft

NASA Technical Reports Server (NTRS)

Crocker, Alan

2010-01-01

In support of new human rated spacecraft development programs, the Mission Operations Directorate at NASA Johnson Space Center has implemented a formal method for the assessment of spacecraft operability. This "Spacecraft Flight Operability Assessment Scale" defines six key themes of flight operability, with guiding principles and goals stated for each factor. A standardized rating technique provides feedback that is useful to the operations, design and program management communities. Applicability of this concept across the program structure and life cycle is addressed. Examples of operationally desirable and undesirable spacecraft design characteristics are provided, as is a sample of the assessment scale product.

7 CFR 43.105 - Operating characteristics (OC) curves.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 43.105 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS STANDARDS FOR SAMPLING PLANS Sampling Plans § 43.105 Operating characteristics (OC...

The impact of airport characteristics on airport surface accidents and incidents.

PubMed

Wilke, Sabine; Majumdar, Arnab; Ochieng, Washington Y

2015-06-01

Airport surface safety and in particular runway and taxiway safety is acknowledged globally as one of aviation's greatest challenges. To improve this key area of aviation safety, it is necessary to identify and understand the causal and contributing factors on safety occurrences. While the contribution of human factors, operations, and procedures has been researched extensively, the impact of the airport and its associated characteristics itself has received little or no attention. This paper introduces a novel methodology for risk and hazard assessment of airport surface operations, and models the relationships between airport characteristics, and (a) the rate of occurrences, (b) the severity of occurrences, and (c) the causal factors underlying occurrences. The results show for the first time how the characteristics of airports, and in particular its infrastructure and operations, influence the safety of surface operations. Copyright © 2015 Elsevier Ltd. and National Safety Council. Published by Elsevier Ltd. All rights reserved.

SNAP 10A ESTIMATED ELECTRICAL CHARACTERISTICS

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

Cooper, J.C.

1961-06-01

The electrical power characteristics of a SNAP 10A converter are estimated for given fractions of power degradation. Graphs are included showing the power characteristics for instantaneous transients from stabilized operation at the maximum efficiency point, and after system temperature stabilization at the operating point. Open-circuit emf's of the converter are estimated for instantaneous and temperature-stabilized cases. (D.L.C.)

Resident training in a new robotic thoracic surgery program.

PubMed

White, Yasmine N; Dedhia, Priya; Bergeron, Edward J; Lin, Jules; Chang, Andrew A; Reddy, Rishindra M

2016-03-01

The volume of robot-assisted operations has drastically increased over the past decade. New programs have focused on training surgeons, whereas resident training has lagged behind. The objective of this study was to evaluate our institutional experience with resident participation in thoracic robotic surgery cases since the initiation of our program. The first 100 robotic thoracic surgery cases at our institution were retrospectively reviewed and categorized into three sequential cohorts. Procedure type, patient and operative characteristics, level of resident participation (primary surgeon [PS] or assistant), and postoperative variables were evaluated. Of the first 100 cases, 38% were lung resections, 23% were esophageal operations, and 20% were sympathectomies. The distribution of cases changed over time with the proportion of pulmonary resections significantly increasing. Patient age (P < 0.05), body mass index (P = not significant [NS]), and comorbidities (P = NS) increased over time. Resident participation as PS increased from 33%-59% between the early and late cohorts (P < 0.05). A subset analysis of the 20 lobectomies (7 attending PS, 13 residents) showed similar patient characteristics (P = NS): age (67 versus 69), body mass index (29.5 versus 26.1), and American Society of Anesthesiologists category (2.8 versus 2.8). Operative and postoperative characteristics were also similar (P = NS) regardless of PS: operative time (260 versus 249 min), estimated blood loss (187 versus 203 mL), and length of stay (4.8 versus 4.7 d). Residents can participate as the PS in a variety of thoracic operations during the implementation of a robotics program. Operative time, estimated blood loss, and length of stay were similar regardless of level of resident participation. Copyright © 2016 Elsevier Inc. All rights reserved.

The minimum test battery to screen for binocular vision anomalies: report 3 of the BAND study.

PubMed

Hussaindeen, Jameel Rizwana; Rakshit, Archayeeta; Singh, Neeraj Kumar; Swaminathan, Meenakshi; George, Ronnie; Kapur, Suman; Scheiman, Mitchell; Ramani, Krishna Kumar

2018-03-01

This study aims to report the minimum test battery needed to screen non-strabismic binocular vision anomalies (NSBVAs) in a community set-up. When large numbers are to be screened we aim to identify the most useful test battery when there is no opportunity for a more comprehensive and time-consuming clinical examination. The prevalence estimates and normative data for binocular vision parameters were estimated from the Binocular Vision Anomalies and Normative Data (BAND) study, following which cut-off estimates and receiver operating characteristic curves to identify the minimum test battery have been plotted. In the receiver operating characteristic phase of the study, children between nine and 17 years of age were screened in two schools in the rural arm using the minimum test battery, and the prevalence estimates with the minimum test battery were found. Receiver operating characteristic analyses revealed that near point of convergence with penlight and red filter (> 7.5 cm), monocular accommodative facility (< 10 cycles per minute), and the difference between near and distance phoria (> 1.25 prism dioptres) were significant factors with cut-off values for best sensitivity and specificity. This minimum test battery was applied to a cohort of 305 children. The mean (standard deviation) age of the subjects was 12.7 (two) years with 121 males and 184 females. Using the minimum battery of tests obtained through the receiver operating characteristic analyses, the prevalence of NSBVAs was found to be 26 per cent. Near point of convergence with penlight and red filter > 10 cm was found to have the highest sensitivity (80 per cent) and specificity (73 per cent) for the diagnosis of convergence insufficiency. For the diagnosis of accommodative infacility, monocular accommodative facility with a cut-off of less than seven cycles per minute was the best predictor for screening (92 per cent sensitivity and 90 per cent specificity). The minimum test battery of near point of convergence with penlight and red filter, difference between distance and near phoria, and monocular accommodative facility yield good sensitivity and specificity for diagnosis of NSBVAs in a community set-up. © 2017 Optometry Australia.

Characteristic operator functions for quantum input-plant-output models and coherent control

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

Gough, John E.

We introduce the characteristic operator as the generalization of the usual concept of a transfer function of linear input-plant-output systems to arbitrary quantum nonlinear Markovian input-output models. This is intended as a tool in the characterization of quantum feedback control systems that fits in with the general theory of networks. The definition exploits the linearity of noise differentials in both the plant Heisenberg equations of motion and the differential form of the input-output relations. Mathematically, the characteristic operator is a matrix of dimension equal to the number of outputs times the number of inputs (which must coincide), but with entriesmore » that are operators of the plant system. In this sense, the characteristic operator retains details of the effective plant dynamical structure and is an essentially quantum object. We illustrate the relevance to model reduction and simplification definition by showing that the convergence of the characteristic operator in adiabatic elimination limit models requires the same conditions and assumptions appearing in the work on limit quantum stochastic differential theorems of Bouten and Silberfarb [Commun. Math. Phys. 283, 491-505 (2008)]. This approach also shows in a natural way that the limit coefficients of the quantum stochastic differential equations in adiabatic elimination problems arise algebraically as Schur complements and amounts to a model reduction where the fast degrees of freedom are decoupled from the slow ones and eliminated.« less

A case study of dissolved air flotation for seasonal high turbidity water in Korea.

PubMed

Kwon, S B; Ahn, H W; Ahn, C J; Wang, C K

2004-01-01

A DAF (Dissolved-Air-Flotation) process has been designed considering raw water quality characteristics in Korea. Although direct filtration is usually operated, DAF is operated when freshwater algae blooms occur or raw water turbidity becomes high. Pre-sedimentation is operated in case when the raw water turbidity is very high due to rainstorms. A main feature of this plant is that the operation mode can be changed (controlled) based on the characteristics of the raw water to optimize the effluent quality and the operation costs. Treatment capacity (surface loading rate) and efficiency of DAF was found to be better than the conventional sedimentation process. Moreover, low-density particles (algae and alum flocs) are easily separated while the removal of them by sedimentation is more difficult. One of the main concerns for DAF operation is a high raw water turbidity. DAF is not adequate for raw water, which is more turbid than 100 NTU. In order to avoid this problem, pre-sedimentation basins are installed in the DAF plant to decrease the turbidity of the DAF inflow. For simulation of the actual operation, bench and full-scale tests were performed for highly turbid water conditions. Consequently, it is suggested that pre-sedimentation with optimum coagulation prior to DAF is the appropriate treatment scheme.

Characteristics of Information Agencies (Libraries) and Information Agents (Librarians) in Highly Productive Computer Software and Services Companies: The Key to Growth and Survival?

ERIC Educational Resources Information Center

Carroll, Margaret Aby; Chandler, Yvonne J.

This study examines whether an analysis of characteristics of libraries or information centers and librarians in highly productive companies yields operational models and standards that can improve their efficiency and effectiveness and their parent organization's productivity. Data was collected using an e-mail survey instrument sent to 500 large…

Infrasound Signal Characteristics from Small Earthquakes

DTIC Science & Technology

2010-09-01

INFRASOUND SIGNAL CHARACTERISTICS FROM SMALL EARTHQUAKES J. Mark Hale1, Stephen J. Arrowsmith2, Chris Hayward3, Relu Burlacu1, Kristine L. Pankow1...ABSTRACT Understanding the source properties responsible for infrasound generation is critical to developing a seismo-acoustic data discriminant...mining in the Utah region create a unique setting for the study of near-field infrasound . The Utah network has been operating three permanent infrasound

Advanced optical blade tip clearance measurement system

NASA Technical Reports Server (NTRS)

Ford, M. J.; Honeycutt, R. E.; Nordlund, R. E.; Robinson, W. W.

1978-01-01

An advanced electro-optical system was developed to measure single blade tip clearances and average blade tip clearances between a rotor and its gas path seal in an operating gas turbine engine. This system is applicable to fan, compressor, and turbine blade tip clearance measurement requirements, and the system probe is particularly suitable for operation in the extreme turbine environment. A study of optical properties of blade tips was conducted to establish measurement system application limitations. A series of laboratory tests was conducted to determine the measurement system's operational performance characteristics and to demonstrate system capability under simulated operating gas turbine environmental conditions. Operational and environmental performance test data are presented.

Interface design in the process industries

NASA Technical Reports Server (NTRS)

Beaverstock, M. C.; Stassen, H. G.; Williamson, R. A.

1977-01-01

Every operator runs his plant in accord with his own mental model of the process. In this sense, one characteristic of an ideal man-machine interface is that it be in harmony with that model. With this theme in mind, the paper first reviews the functions of the process operator and compares them with human operators involved in control situations previously studied outside the industrial environment (pilots, air traffic controllers, helmsmen, etc.). A brief history of the operator interface in the process industry and the traditional methodology employed in its design is then presented. Finally, a much more fundamental approach utilizing a model definition of the human operator's behavior is presented.

Leadership and characteristics of nonprofit mental health peer-run organizations nationwide.

PubMed

Ostrow, Laysha; Hayes, Stephania L

2015-04-01

Mental health peer-run organizations are nonprofits providing venues for support and advocacy among people diagnosed as having mental disorders. It has been proposed that consumer involvement is essential to their operations. This study reported organizational characteristics of peer-run organizations nationwide and how these organizations differ by degree of consumer control. Data were from the 2012 National Survey of Peer-Run Organizations. The analyses described the characteristics of the organizations (N=380) on five domains of nonprofit research, comparing results for organizations grouped by degree of involvement by consumers in the board of directors. Peer-run organizations provided a range of supports and educational and advocacy activities and varied in their capacity and resources. Some variation was explained by the degree of consumer control. These organizations seemed to be operating consistently with evidence on peer-run models. The reach of peer-run organizations, and the need for in-depth research, continues to grow.

Operational Suitability Guide. Volume 2. Templates

DTIC Science & Technology

1990-05-01

Intended mission, and the required technical and operational characteristics. The mission must be adequately defined and key hardware and software ...operational availability. With the use of fault-tolerant computer hardware and software , the system R&M will significantly improve end-to-end...should Include both hardware and software elements, as appropriate. Unique characteristics or unique support concepts should be Identified if they result

Diaphragm and Lung Ultrasound to Predict Weaning Outcome: Systematic Review and Meta-Analysis.

PubMed

Llamas-Álvarez, Ana M; Tenza-Lozano, Eva M; Latour-Pérez, Jaime

2017-12-01

Deciding the optimal timing for extubation in patients who are mechanically ventilated can be challenging, and traditional weaning predictor tools are not very accurate. The aim of this systematic review and meta-analysis was to assess the accuracy of lung and diaphragm ultrasound for predicting weaning outcomes in critically ill adults. MEDLINE, the Cochrane Library, Web of Science, Scopus, LILACS, Teseo, Tesis Doctorales en Red, and OpenGrey were searched, and the bibliographies of relevant studies were reviewed. Two researchers independently selected studies that met the inclusion criteria and assessed study quality in accordance with the Quality Assessment of Diagnostic Accuracy Studies-2 tool. The summary receiver-operating characteristic curve and pooled diagnostic OR (DOR) were estimated by using a bivariate random effects analysis. Sources of heterogeneity were explored by using predefined subgroup analyses and bivariate meta-regression. Nineteen studies involving 1,071 people were included in the study. For diaphragm thickening fraction, the area under the summary receiver-operating characteristic curve was 0.87, and DOR was 21 (95% CI, 11-40). Regarding diaphragmatic excursion, pooled sensitivity was 75% (95% CI, 65-85); pooled specificity, 75% (95% CI, 60-85); and DOR, 10 (95% CI, 4-24). For lung ultrasound, the area under the summary receiver-operating characteristic curve was 0.77, and DOR was 38 (95% CI, 7-198). Based on bivariate meta-regression analysis, a significantly higher specificity for diaphragm thickening fraction and higher sensitivity for diaphragmatic excursion was detected in studies with applicability concerns. Lung and diaphragm ultrasound can help predict weaning outcome, but its accuracy may vary depending on the patient subpopulation. Copyright © 2017 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

Unstable behaviour of RPT when testing turbine characteristics in the laboratory

NASA Astrophysics Data System (ADS)

Nielsen, T. K.; Fjørtoft Svarstad, M.

2014-03-01

A reversible pump turbine is a machine that can operate in three modes of operation i.e. in pumping mode. in turbine mode and in phase compensating mode (idle speed). Reversible pump turbines have an increasing importance for regulation purposes for obtaining power balance in electric power systems. Especially in grids dominated by thermal energy. reversible pump turbines improve the overall power regulating ability. Increased use of renewables (wind-. wave- and tidal power plants) will utterly demand better regulation ability of the traditional water power systems. enhancing the use of reversible pump turbines. A reversible pump turbine is known for having incredible steep speed - flow characteristics. As the speed increases the flow decreases more than that of a Francis turbines with the same specific speed. The steep characteristics might cause severe stability problems in turbine mode of operation. Stability in idle speed is a necessity for phasing in the generator to the electric grid. In the design process of a power plant. system dynamic simulations must be performed in order to check the system stability. The turbine characteristics will have to be modelled with certain accuracy even before one knows the exact turbine design and have measured characteristics. A representation of the RPT characteristics for system dynamic simulation purposes is suggested and compared with measured characteristics. The model shows good agreement with RPT characteristics measured in The Waterpower Laboratory. Because of the S-shaped characteristics. there is a stability issue involved when measuring these characteristics. Without special measures. it is impossible to achieve stable conditions in certain operational points. The paper discusses the mechanism when using a throttle to achieve system stability. even if the turbine characteristics imply instability.

Frontline Nurse Engagement and Empowerment: Characteristics and Processes for Building Leadership Capacity.

PubMed

Riley, Bettina H; Dearmon, Valorie; Mestas, Lisa; Buckner, Ellen B

2016-01-01

Improving health care quality is the responsibility of nurses at all levels of the organization. This article describes a study that examined frontline staff nurses' professional practice characteristics to advance leadership through the understanding of relationships among practice environment, quality improvement, and outcomes. The study design was a descriptive quantitative design at 2 time points. Findings support the use of research and quality processes to build leadership capacity required for positive resolution of interdisciplinary operational failures.

Dual nozzle aerodynamic and cooling analysis study

NASA Technical Reports Server (NTRS)

Meagher, G. M.

1981-01-01

Analytical models to predict performance and operating characteristics of dual nozzle concepts were developed and improved. Aerodynamic models are available to define flow characteristics and bleed requirements for both the dual throat and dual expander concepts. Advanced analytical techniques were utilized to provide quantitative estimates of the bleed flow, boundary layer, and shock effects within dual nozzle engines. Thermal analyses were performed to define cooling requirements for baseline configurations, and special studies of unique dual nozzle cooling problems defined feasible means of achieving adequate cooling.

Operational Determination of Physical and Mechanical Properties of Cast Samples of High-Strength Iron by Means of a Magnetic-Mechanical Method

NASA Astrophysics Data System (ADS)

Slyusarev, Yu. K.; Braga, A. V.; Slyusarev, I. Yu.

2017-09-01

The effect of the chemical composition of high-strength cast iron VCh35 on the content, shape and diameter of graphite inclusions and on the presence of structurally-free cementite and defects is studied. A relationship is determined between the structure and metallurgical defects and characteristics of the mechanical and magnetic rigidity of cast samples. Relationships are established in a group of factors and property characteristics: chemical composition - microstructure - mechanical rigidity - magnetic stiffness. The basis of a method is established making it possible to perform operative non-destructive monitoring of the melt quality preparation for high-strength iron casting.

A design rationale for NASA TileWorld

NASA Technical Reports Server (NTRS)

Philips, Andrew B.; Swanson, Keith J.; Drummond, Mark E.; Bresina, John L.

1991-01-01

Automated systems that can operate in unrestricted real-world domains are still well beyond current computational capabilities. This paper argues that isolating essential problem characteristics found in real-world domains allows for a careful study of how particular control systems operate. By isolating essential problem characteristics and studying their impact on autonomous system performance, we should be able to more quickly deliver systems for practical real-world problems. For our research on planning, scheduling, and control, we have selected three particular domain attributes to study: exogenous events, uncertain action outcome, and metric time. We are not suggesting that studies of these attributes in isolation are sufficient to guarantee the obvious goals of good methodology, brilliant architectures, or first-class results; however, we are suggesting that such isolation facilitates the achievement of these goals. To study these attributes, we have developed the NASA TileWorld. We describe the NASA TileWorld simulator in general terms, present an example NASA TileWorld problem, and discuss some of our motivations and concerns for NASA TileWorld.

Preliminary noise tradeoff study of a Mach 2.7 cruise aircraft

NASA Technical Reports Server (NTRS)

Mascitti, V. R.; Maglieri, D. J. (Editor); Raney, J. P. (Editor)

1979-01-01

NASA computer codes in the areas of preliminary sizing and enroute performance, takeoff and landing performance, aircraft noise prediction, and economics were used in a preliminary noise tradeoff study for a Mach 2.7 design supersonic cruise concept. Aerodynamic configuration data were based on wind-tunnel model tests and related analyses. Aircraft structural characteristics and weight were based on advanced structural design methodologies, assuming conventional titanium technology. The most advanced noise prediction techniques available were used, and aircraft operating costs were estimated using accepted industry methods. The 4-engines cycles included in the study were based on assumed 1985 technology levels. Propulsion data was provided by aircraft manufacturers. Additional empirical data is needed to define both noise reduction features and other operating characteristics of all engine cycles under study. Data on VCE design parameters, coannular nozzle inverted flow noise reduction and advanced mechanical suppressors are urgently needed to reduce the present uncertainties in studies of this type.

Heat transfer characteristics of a surface type direct contact boiler

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

Deeds, R.S.; Jacobs, H.R.; Boehm, R.F.

1976-03-01

Two direct contact heat exchangers were constructed and test results were obtained using water and refrigerant 113 as the working fluids. The heat exchangers were operated in a three-phase mode; the water remained liquid throughout the vessel and the liquid refrigerant 113 underwent vaporization following direct injection into the water. The effect of important operational parameters--operating heights, refrigerant 113 injection techniques, mass flow ratios, and temperatures--was studied to determine generalized trends important in the design and operation of a prototype three-phase direct contact heat exchanger. The primary system used in this study performed well overall. The initial favorable results ofmore » this study warrant further investigation of direct contact heat exchange as a means of utilizing geothermal energy.« less

Investigation of dynamic characteristics of a turbine-propeller engine

NASA Technical Reports Server (NTRS)

Oppenheimer, Frank L; Jacques, James R

1951-01-01

Time constants that characterize engine speed response of a turbine-propeller engine over the cruising speed range for various values of constant fuel flow and constant blade angle were obtained both from steady-state characteristics and from transient operation. Magnitude of speed response to changes in fuel flow and blade angle was investigated and is presented in the form of gain factors. Results indicate that at any given value of speed in the engine cruising speed range, time constants obtained both from steady-state characteristics and from transient operation agree satisfactorily for any given constant fuel flow, whereas time constants obtained from transient operation exceed time constants obtained from steady-state characteristics by approximately 14 percent for any given blade angle.

Characteristics of the assistance to pilgrims in the National Sanctuary of Our Lady of Aparecida, São Paulo, Brazil, 2011-2014.

PubMed

Carmo, Hercules de Oliveira; Valente, Tânia Cristina Oliveira

2017-01-01

to describe the characteristics of the health assistance for pilgrims visiting the National Sanctuary of Our Lady of Aparecida and to investigate health care strategies in periods of peak of religious tourism. a descriptive study using outpatient medical records from 2011 to 2014, for a detailed analysis for the month of October 2014 and the operational documents for health care in periods of mass events in the medical clinic of the Sanctuary. 95,011 people were assisted in the period, 2,266 in October 2014; the higher demand for assistance was from elderly individuals (33%), women (59%), and people from the Brazilian Southeast region (79%); there were no operational documents for specific actions for this period. the large number of visitors, associated with the frequency of mass events and the absence of an operating plan, may pose a serious public health scenario for that region.

The reaction of the cardio-vascular and sympathico-adrenal systems to intellectual activity with emotional stress. [human operator performance

NASA Technical Reports Server (NTRS)

Tomashevskaya, L. I.

1975-01-01

The effect of emotiogenic factors on an operator's intellectual activity were studied for differing working regimes on an experimental control panel that provided for light, sonic, and electrocutaneous stimuli. The latter stimulus was activated automatically if the subject gave an incorrect response. It was shown that the working capacity of the operator under stress depends to a great extent on the effect of the emotiogenic factors on the individual functioning characteristics of the cardiovascular and sympathetic-adrenal systems. Moral, intellectual, willpower, emotional, and other personality traits are decisive factors of operator function.

EVALUATION OF PERSONAL COOLING DEVICES FOR A DIOXIN CLEAN-UP OPERATION

EPA Science Inventory

The study investigated the use of personal coolers to increase worker productivity and safety while working at elevated, ambient temperatures cleaning up dioxin contaminated soil.^The study included laboratory tests to measure the thermal characteristics of the chemical protectiv...

On-board multispectral classification study. Volume 2: Supplementary tasks. [adaptive control

NASA Technical Reports Server (NTRS)

Ewalt, D.

1979-01-01

The operational tasks of the onboard multispectral classification study were defined. These tasks include: sensing characteristics for future space applications; information adaptive systems architectural approaches; data set selection criteria; and onboard functional requirements for interfacing with global positioning satellites.

Low power DC arcjet operation with hydrogen/nitrogen/ammonia mixtures

NASA Technical Reports Server (NTRS)

Hardy, Terry L.; Curran, Francis M.

1987-01-01

The effect of gas composition and ambient pressure on arcjet operation was determined. Arcjet operation in different facilities was also compared to determine the validity of tests in small facilities. Volt-ampere characteristics were determined for an arcjet using hydrogen/nitrogen mixtures (simulating both ammonia and hydrazine), hydrogen/nitrogen/ammonia mixtures, and pure ammonia as propellants at various flow rates. The arcjet had a typical performance of 450 sec specific impulse at 1 kW with hydrogen/nitrogen mixures. It was determined that the amount of ammonia present in the gas stream had a significant effect on the arcjet volt-ampere characteristics. Also, hydrogen/nitrogen mixtures simulating ammonia gave arc characteristics approximately the same as those of pure ammonia. Finally, no differences in arc volt-ampere characteristics were seen between low and high ambient pressure operation in the same facility. A 3 to 5 V difference was seen when different facilities were compared, but this difference was probably due to differences in the voltage drops across the current connections, and not due to arcjet operational differences in the two facilities.

Low power dc arcjet operation with hydrogen/nitrogen/ammonia mixtures

NASA Technical Reports Server (NTRS)

Hardy, Terry L.; Curran, Francis M.

1986-01-01

The effect of gas composition and ambient pressure on arcjet operation was determined. Arcjet operation in different facilities was also compared to determine the validity of tests in small facilities. Volt-ampere characteristics were determined for an arcjet using hydrogen/nitrogen mixtures (simulating both ammonia and hydrazine), hydrogen/nitrogen/ammonia mixtures, and pure ammonia as propellants at various flow rates. The arcjet had a typical performance of 450 sec specific impulse at 1 kW with hydrogen/nitrogen mixtures. It was determined that the amount of ammonia present in the gas stream had a significant effect on the arcjet volt-ampere characteristics. Also, hydrogen/nitrogen mixtures simulating ammonia gave arc characteristics approximately the same as those of pure ammonia. Finally, no differences in arc volt-ampere characteristics were seen between low and high ambient pressure operation in the same facility. A 3 to 5 V difference was seen when different facilities were compared, but this difference was probably due to differences in the voltage drops across the current connections, and not due to arcjet operational differences in the two facilities.

The characteristics of railway service disruption: implications for disruption management.

PubMed

Golightly, D; Dadashi, N

2017-03-01

Rail disruption management is central to operational continuity and customer satisfaction. Disruption is not a unitary phenomenon - it varies by time, cause, location and complexity of coordination. Effective, user-centred technology for rail disruption must reflect this variety. A repertory grid study was conducted to elicit disruption characteristics. Construct elicitation with a group of experts (n = 7) captured 26 characteristics relevant to rail disruption. A larger group of operational staff (n = 28) rated 10 types of rail incident against the 26 characteristics. The results revealed distinctions such as business impact and public perception, and the importance of management of the disruption over initial detection. There were clear differences between those events that stop the traffic, as opposed to those that only slow the traffic. The results also demonstrate the utility of repertory grid for capturing the characteristics of complex work domains. Practitioner Summary: The aim of the paper is to understand how variety in rail disruption influences socio-technical design. It uses repertory grid to identify and prioritise 26 constructs, and group 10 disruption types, identifying critical factors such as whether an incident stops or merely slows the service, and business reputation.

Regression modeling and prediction of road sweeping brush load characteristics from finite element analysis and experimental results.

PubMed

Wang, Chong; Sun, Qun; Wahab, Magd Abdel; Zhang, Xingyu; Xu, Limin

2015-09-01

Rotary cup brushes mounted on each side of a road sweeper undertake heavy debris removal tasks but the characteristics have not been well known until recently. A Finite Element (FE) model that can analyze brush deformation and predict brush characteristics have been developed to investigate the sweeping efficiency and to assist the controller design. However, the FE model requires large amount of CPU time to simulate each brush design and operating scenario, which may affect its applications in a real-time system. This study develops a mathematical regression model to summarize the FE modeled results. The complex brush load characteristic curves were statistically analyzed to quantify the effects of cross-section, length, mounting angle, displacement and rotational speed etc. The data were then fitted by a multiple variable regression model using the maximum likelihood method. The fitted results showed good agreement with the FE analysis results and experimental results, suggesting that the mathematical regression model may be directly used in a real-time system to predict characteristics of different brushes under varying operating conditions. The methodology may also be used in the design and optimization of rotary brush tools. Copyright © 2015 Elsevier Ltd. All rights reserved.

Analysis of self-oscillating dc-to-dc converters

NASA Technical Reports Server (NTRS)

Burger, P.

1974-01-01

The basic operational characteristics of dc-to-dc converters are analyzed along with the basic physical characteristics of power converters. A simple class of dc-to-dc power converters are chosen which could satisfy any set of operating requirements, and three different controlling methods in this class are described in detail. Necessary conditions for the stability of these converters are measured through analog computer simulation whose curves are related to other operational characteristics, such as ripple and regulation. Further research is suggested for the solution of absolute stability and efficient physical design of this class of power converters.

Experimental study of operation performance for hydrocarbon fuel pump with low specific speed

NASA Astrophysics Data System (ADS)

Wu, Xianyu; Yang, Jun; Jin, Xuan

2017-10-01

In this paper, a small flow rate hydrocarbon turbine pump was used to pressurize the fuel supply system of scramjet engine. Some experiments were carried out to investigate the characteristics of turbine pump driven by nitrogen or combustion gas under different operating conditions. A experimental database with regard to the curves of the rotational speed, mass flow rate and net head with regard to centrifugal pump were plotted. These curves were represented as functions of the pressure and temperature at turbine inlet/outlet and the throttle diameter at downstream of centrifugal pump. A sensitivity study has been carried out based on design of experiments. The experimental was employed to analyze net head of centrifugal and throttle characteristics. The research results can accumulate foundations for the close loop control system of turbine pump.

Spatio-temporal organization of dynamics in a two-dimensional periodically driven vortex flow: A Lagrangian flow network perspective.

PubMed

Lindner, Michael; Donner, Reik V

2017-03-01

We study the Lagrangian dynamics of passive tracers in a simple model of a driven two-dimensional vortex resembling real-world geophysical flow patterns. Using a discrete approximation of the system's transfer operator, we construct a directed network that describes the exchange of mass between distinct regions of the flow domain. By studying different measures characterizing flow network connectivity at different time-scales, we are able to identify the location of dynamically invariant structures and regions of maximum dispersion. Specifically, our approach allows us to delimit co-existing flow regimes with different dynamics. To validate our findings, we compare several network characteristics to the well-established finite-time Lyapunov exponents and apply a receiver operating characteristic analysis to identify network measures that are particularly useful for unveiling the skeleton of Lagrangian chaos.

Skin color parameters and Fitzpatrick phototypes in estimating the risk of skin cancer: A case-control study in the Polish population.

PubMed

Sitek, Aneta; Rosset, Iwona; Żądzińska, Elżbieta; Kasielska-Trojan, Anna; Neskoromna-Jędrzejczak, Aneta; Antoszewski, Bogusław

2016-04-01

Light skin pigmentation is a known risk factor for skin cancer. Skin color parameters and Fitzpatrick phototypes were evaluated in terms of their usefulness in predicting the risk of skin cancer. A case-control study involved 133 individuals with skin cancer (100 with basal cell carcinoma, 21 with squamous cell carcinoma, 12 with melanoma) and 156 healthy individuals. All of them had skin phototype determined and spectrophotometric skin color measurements were done on the inner surfaces of their arms and on the buttock. Using those data, prediction models were built and subjected to 17-fold stratified cross-validation. A model, based on skin phototypes, was characterized by area under the receiver operating characteristic curve = 0.576 and exhibited a lower predictive power than the models, which were mostly based on spectrophotometric variables describing pigmentation levels. The best predictors of skin cancer were R coordinate of RGB color space (area under the receiver operating characteristic curve 0.687) and melanin index (area under the receiver operating characteristic curve 0.683) for skin on the buttock. A small number of patients were studied. Models were not externally validated. Skin color parameters are more accurate predictors of skin cancer occurrence than skin phototypes. Spectrophotometry is a quick, easy, and affordable method offering relatively good predictive power. Copyright © 2015 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

Investigation of the Effects of Facility Background Pressure on the Performance and Voltage-Current Characteristics of the High Voltage Hall Accelerator

NASA Technical Reports Server (NTRS)

Kamhawi, Hani; Huang, Wensheng; Haag, Thomas; Spektor, Rostislav

2014-01-01

The National Aeronautics and Space Administration (NASA) Science Mission Directorate In-Space Propulsion Technology office is sponsoring NASA Glenn Research Center to develop a 4 kW-class Hall thruster propulsion system for implementation in NASA science missions. A study was conducted to assess the impact of varying the facility background pressure on the High Voltage Hall Accelerator (HiVHAc) thruster performance and voltage-current characteristics. This present study evaluated the HiVHAc thruster performance in the lowest attainable background pressure condition at NASA GRC Vacuum Facility 5 to best simulate space-like conditions. Additional tests were performed at selected thruster operating conditions to investigate and elucidate the underlying physics that change during thruster operation at elevated facility background pressure. Tests were performed at background pressure conditions that are three and ten times higher than the lowest realized background pressure. Results indicated that the thruster discharge specific impulse and efficiency increased with elevated facility background pressure. The voltage-current profiles indicated a narrower stable operating region with increased background pressure. Experimental observations of the thruster operation indicated that increasing the facility background pressure shifted the ionization and acceleration zones upstream towards the thrusters anode. Future tests of the HiVHAc thruster are planned at background pressure conditions that are expected to be two to three times lower than what was achieved during this test campaign. These tests will not only assess the impact of reduced facility background pressure on thruster performance, voltage-current characteristics, and plume properties; but will also attempt to quantify the magnitude of the ionization.

Estimating Durability of Reinforced Concrete

NASA Astrophysics Data System (ADS)

Varlamov, A. A.; Shapovalov, E. L.; Gavrilov, V. B.

2017-11-01

In this article we propose to use the methods of fracture mechanics to evaluate concrete durability. To evaluate concrete crack resistance characteristics of concrete directly in the structure in order to implement the methods of fracture mechanics, we have developed special methods. Various experimental studies have been carried out to determine the crack resistance characteristics and the concrete modulus of elasticity during its operating. A comparison was carried out for the results obtained with the use of the proposed methods and those obtained with the standard methods for determining the concrete crack resistance characteristics.

The Effects of Target and Missile Characteristics on Theoretical Minimum Miss Distance for a Beam-Rider Guidance System in the Presence of Noise

NASA Technical Reports Server (NTRS)

Stewart, Elwood C.; Druding, Frank; Nishiura, Togo

1959-01-01

A study has been made to determine the relative importance of those factors which place an inherent limitation on the minimum obtainable miss distance for a beam-rider navigation system operating in the presence of glint noise and target evasive maneuver. Target and missile motions are assumed to be coplanar. The factors considered are the missile natural frequencies and damping ratios, missile steady-state acceleration capabilities, target evasive maneuver characteristics, and angular scintillation noise characteristics.

Some Operating Experience and Problems Encountered During Operation of a Free-jet Facility

NASA Technical Reports Server (NTRS)

Mcaulay, John E; Prince, William R

1957-01-01

During a free-jet investigation of a 28-inch ram-jet engine at a Mach number of 2.35, flow pulsation at the engine inlet were discovered which proved to have an effect on the engine performance and operational characteristics, particularly the engine rich blowout limits. This report discusses the finding of the flow pulsations, their elimination, and effect. Other facility characteristics, such as the establishment of flow simulation and the degree of subcritical operation of the diffuser, are also explained.

Study of airborne science experiment management concepts for application to space shuttle. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

Mulholland, D. R.; Reller, J. O., Jr.; Neel, C. B.; Haughney, L. C.

1973-01-01

The management concepts and operating procedures are documented as they apply to the planning of shuttle spacelab operations. Areas discussed include: airborne missions; formulation of missions; management procedures; experimenter involvement; experiment development and performance; data handling; safety procedures; and applications to shuttle spacelab planning. Characteristics of the airborne science experience are listed, and references and figures are included.

Pharmacotherapy Evaluation and Utilization in Coronary Artery Bypass Grafting Patients in Kosovo during the Period 2016-2017

PubMed Central

Daci, Armond; Bozalija, Adnan; Cavolli, Raif; Alaj, Rame; Beretta, Giangiacomo; Krasniqi, Shaip

2018-01-01

BACKGROUND: Coronary Artery Bypass Grafting (CABG) is realised in patients with critical or advanced disease of coronary arteries. There are different pharmacotherapeutic approaches which are used as management, treatment and preventive therapy in cardiovascular disease or related comorbidities. Performing a successful surgery, pharmacotherapy, and increase of bypass patency rate remains a serious challenge. AIM: This study aims to analyse the patient characteristics undergoing CABG and evaluation of their drug utilisation rate and daily dosages in the perioperative period. MATERIAL AND METHODS: Data were collected from 102 patients in the period 2016-2017 and detailed therapeutic prescription and dosages, patient characteristics were analysed before the operation, after the operation and visit after operation in the Clinic of Cardiac surgery-University Clinical Center of Kosovo. RESULTS: Our findings had shown that patients provided to have normal biochemical parameters in the clinic before the operation, and were related to cardiovascular diseases and comorbidities and risk factors with mainly elective intervention. The, however, higher utilisation of cardiovascular drugs such as beta blockers, diuretics, anticoagulants, statins and lower calcium blockers, ACEi, ARBs, hydrochlorothiazide, amiodarone were founded. ARBs, beta blockers, statins, nitrates and nadroparin utilisation decreased after operation and visit after the operation, whereas amiodarone only in the visit after the operation. Diuretics are increased after the operation which decreases in the visit after the operation. Regarding the daily dosage, only metoprolol was increased in the visit after operation (P < 0.001) and visit after operation (P < 0.05) whereas losartan and furosemide were increased (P < 0.01) and (P < 0.05) respectively. CONCLUSION: The study showed that beta blockers, statins, aspirin, nitrates (before the operation), furosemide and spironolactone are the most utilised drugs. However, we found low utilisation rate for ACEi, ARBs, clopidogrel, nadroparin, warfarin, xanthines, amiodarone, calcium blockers. Daily dosages were different compared to before CABG only in metoprolol, losartan, and furosemide. PMID:29610608

A study of flux control for high-efficiency speed control of variable flux permanent magnet motor

NASA Astrophysics Data System (ADS)

Kim, Young Hyun; Lee, Seong Soo; Lee, Jung Ho

2018-05-01

In this study, we evaluate the performance of permanent magnets (PMs). The efficiency of attraction in the high speed region was studied using the variable flux memory motor (VFMM). It is presented in order to analyze the magnetic characteristics of PMs, using the second quadrant plan data with re- and de-magnetization. In addition, this study focuses on the evaluation of operational characteristics relative to the magnetizing directions according to the d-axis currents, by using one of the finite element solutions. The feasibility of application for the VFMM has been experimentally demonstrated.

Shooting gallery operation in the context of establishing a medically supervised injecting center: Sydney, Australia.

PubMed

Kimber, Jo; Dolan, Kate

2007-03-01

Shooting galleries (SGs) are illicit off-street spaces close to drug markets used for drug injection. Supervised injecting facilities (SIFs) are low threshold health services where injecting drug users (IDUs) can inject pre-obtained drugs under supervision. This study describes SG use in Kings Cross, Sydney before and after the opening of the Sydney Medically Supervised Injecting Centre (MSIC), Australia's first SIF. Operational and environmental characteristics of SGs, reasons for SG use, and willingness to use MSIC were also examined. An exploratory survey of SG users (n = 31), interviews with SG users (n = 17), and drug workers (n = 8), and counts of used needles routinely collected from SGs (6 months before and after MSIC) and visits to the MSIC (6 months after MSIC) were triangulated. We found five SGs operated during the study period. Key operational characteristics were 24-h operation, AUS $10 entry fee, 30-min time limit, and dual use for sex work. Key reasons for SG use were to avoid police, a preference not to inject in public, and assistance from SG operators in case of overdose. SG users reported high levels of willingness to use the MSIC. The number of used needles collected from SGs decreased by 69% (41,819 vs. 12,935) in the 6 months after MSIC opened, while MSIC visits increased incrementally. We conclude that injections were transferred from SGs to the MSIC, but SGs continued to accommodate injections and harm reduction outreach should be maintained.

Astronaut activity in weightlessness and unsupported space

NASA Technical Reports Server (NTRS)

Ivanov, Y. A.; Popov, V. A.; Kachaturyants, L. S.

1975-01-01

For the purpose of study of the performance ability of a human operator in prolonged weightless conditions was studied by the following methods: (1) psychophysiological analysis of certain operations; (2) the dynamic characteristics of a man, included in a model control system, with direct and delayed feedback; (3) evaluation of the singularities of analysis and quality of the working memory, in working with outlines of patterned and random lines; and (4) biomechanical analysis of spatial orientation and motor activity in unsupported space.

Design definition study of a lift/cruise fan technology V/STOL airplane: Summary

NASA Technical Reports Server (NTRS)

Zabinsky, J. M.; Higgins, H. C.

1975-01-01

A two-engine three-fan V/STOL airplane was designed to fulfill naval operational requirements. A multimission airplane was developed from study of specific point designs. Based on the multimission concept, airplanes were designed to demonstrate and develop the technology and operational procedures for this class of aircraft. Use of interconnected variable pitch fans led to a good balance between high thrust with responsive control and efficient thrust at cruise speeds. The airplanes and their characteristics are presented.

Results from conceptual design study of potential early commercial MHD/steam power plants

NASA Technical Reports Server (NTRS)

Hals, F.; Kessler, R.; Swallom, D.; Westra, L.; Zar, J.; Morgan, W.; Bozzuto, C.

1981-01-01

This paper presents conceptual design information for a potential early MHD power plant developed in the second phase of a joint study of such plants. Conceptual designs of plant components and equipment with performance, operational characteristics and costs are reported on. Plant economics and overall performance including full and part load operation are reviewed. Environmental aspects and the methods incorporated in plant design for emission control of sulfur and nitrogen oxides are reviewed. Results from reliability/availability analysis conducted are also included.

Study of aircraft in intraurban transportation systems

NASA Technical Reports Server (NTRS)

Stout, E. G.

1972-01-01

A systems analysis was conducted to define the technical economic and operational characteristics of an aircraft transportation system for short-range intracity commutor operations. The analysis was for 1975 and 1985 in the seven county, Detroit, Michigan area. STOL and VTOL aircraft were studied in sizes from 40 to 120 passengers. The preferred vehicle for the Detroit area was the deflected slipstream STOL. Since the study was parametric in nature, it is applicable to generalization, and it was concluded that a feasible intraurban air transportation system could be developed in many viable situations.

14 CFR 33.65 - Surge and stall characteristics.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Section 33.65 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.65 Surge and stall characteristics. When the engine is operated in accordance with operating instructions required by...

14 CFR 33.65 - Surge and stall characteristics.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Section 33.65 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.65 Surge and stall characteristics. When the engine is operated in accordance with operating instructions required by...

Operator performance evaluation using multi criteria decision making methods

NASA Astrophysics Data System (ADS)

Rani, Ruzanita Mat; Ismail, Wan Rosmanira; Razali, Siti Fatihah

2014-06-01

Operator performance evaluation is a very important operation in labor-intensive manufacturing industry because the company's productivity depends on the performance of its operators. The aims of operator performance evaluation are to give feedback to operators on their performance, to increase company's productivity and to identify strengths and weaknesses of each operator. In this paper, six multi criteria decision making methods; Analytical Hierarchy Process (AHP), fuzzy AHP (FAHP), ELECTRE, PROMETHEE II, Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) and VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) are used to evaluate the operators' performance and to rank the operators. The performance evaluation is based on six main criteria; competency, experience and skill, teamwork and time punctuality, personal characteristics, capability and outcome. The study was conducted at one of the SME food manufacturing companies in Selangor. From the study, it is found that AHP and FAHP yielded the "outcome" criteria as the most important criteria. The results of operator performance evaluation showed that the same operator is ranked the first using all six methods.

Shuttle derived vehicle analysis solid booster unmanned launch vehicle concept definition study, volume 2

NASA Technical Reports Server (NTRS)

1983-01-01

The technical effort associated with the selection and definition of the recommended SRB-X concept is documented. Included are discussions concerning the trades leading to the selected concept, the analysis that established the concept's basic subsystem characteristics, selected configuration description and performance capabilities, launch site operations and facility needs, development schedule, cost characteristics, risk assessment, and a cursory comparison with other launch systems.

Design study of RL10 derivatives. Volume 3, part 1: Preliminary interface control document. [development of baseline engines for space tug vehicles

NASA Technical Reports Server (NTRS)

Adams, A.

1973-01-01

The Interface Control Document contains engine information necessary for installation of the baseline RL10 Derivative engines in the Space Tug vehicle. The ICD presents a description of the baseline engines and their operating characteristics, mass and load characteristics, and environmental criteria. The document defines the engine/vehicle mechanical, electrical, fluid and pneumatic interface requirements.

Features of Synchronous Electronically Commutated Motors in Servomotor Operation Modes

NASA Astrophysics Data System (ADS)

Dirba, J.; Lavrinovicha, L.; Dobriyan, R.

2017-04-01

The authors consider the features and operation specifics of the synchronous permanent magnet motors and the synchronous reluctance motors with electronic commutation in servomotor operation modes. Calculation results show that mechanical and control characteristics of studied motors are close to a linear shape. The studied motor control is proposed to implement similar to phase control of induction servomotor; it means that angle θ (angle between vectors of the supply voltage and non-load electromotive force) or angle ɛ (angle between rotor direct axis and armature magnetomotive force axis) is changed. The analysis results show that synchronous electronically commutated motors could be used as servomotors.

Association of bond, market, operational, and financial factors with multi-hospital system bond issues.

PubMed

Carpenter, C E; McCue, M J; Hossack, J B

2001-01-01

Despite the growth of multi-hospital systems in the 1990s, their performance in the tax-exempt bond market has not been adequately evaluated. The purpose of this study is to compare bonds issued by multi-hospital systems to those issued by individual hospitals in terms of bond, market, operational, and financial characteristics. The study sample includes 2,078 newly issued, tax-exempt, revenue bonds between 1991 and 1997. The findings indicate that multi-hospital systems issued larger amounts of debt at a lower cost, were more likely to be insured, had higher debt service coverage and higher operating margins.

Field Emission Characteristics of Carbon Nanotubes and Their Applications in Sensors and Devices

NASA Astrophysics Data System (ADS)

Vaseashta, Ashok

2003-03-01

FIELD EMISSION CHARACTERISTICS OF CARBON NANOTUBES AND THEIR APPLICATIONS IN SENSORS AND DEVICES A. Vaseashta, C. Shaffer, M. Collins, A. Mwuara Dept of Physics, Marshall University, Huntington, WV V. Pokropivny Institute for Materials Sciences of NASU, Kiev, Ukraine. D. Dimova-Malinovska Bulgarian Academy of Sciences, Sofia, Bulgaria. The dimensionality of a system has profound influence on its physical behavior. With advances in technology over the past few decades, it has become possible to fabricate and study reduced-dimensional systems, such as carbon nanotubes (CNTs). Carbon nanotubes are especially promising candidate for cold cathode field emitter because of their electrical properties, high aspect ratio, and small radius of curvature at the tips. Electron emission from the carbon nanotubes was investigated. Based upon the field emission investigation of carbon nanotubes, several prototype devices have been suggested that operate with low swing voltages with sufficient high current densities. Characteristics that allow improved current stability and long lifetime operation for electrical and opto-electronics devices are presented. The aim of this brief overview is to illustrate the useful characteristics of carbon nanotubes and its possible application.

Investigation of boundary layer and turbulence characteristics inside the passages of an axial flow inducer

NASA Technical Reports Server (NTRS)

Anand, A.; Gorton, C.; Lakshminarayana, B.; Yamaoka, H.

1973-01-01

A study of the boundary layer and turbulence characteristics inside the passages of an axial flow inducer is reported. The first part deals with the analytical and experimental investigation of the boundary layer characteristics in a four bladed flat plate inducer passage operated with no throttle. An approximate analysis for the prediction of radial and chordwise velocity profiles across the passage is carried out. The momentum integral technique is used to predict the gross properties of the boundary layer. Equations are given for the exact analysis of the turbulent boundary layer characteristics using the turbulent field method. Detailed measurement of boundary layer profiles, limiting streamline angle and skin friction stress on the rotating blade is also reported. Part two of this report deals with the prediction of the flow as well as blade static pressure measurements in a three bladed inducer with cambered blades operated at a flow coefficient of 0.065. In addition, the mean velocity and turbulence measurements carried out inside the passage using a rotating triaxial probe is reported.

Estimation technique of corrective effects for forecasting of reliability of the designed and operated objects of the generating systems

NASA Astrophysics Data System (ADS)

Truhanov, V. N.; Sultanov, M. M.

2017-11-01

In the present article researches of statistical material on the refusals and malfunctions influencing operability of heat power installations have been conducted. In this article the mathematical model of change of output characteristics of the turbine depending on number of the refusals revealed in use has been presented. The mathematical model is based on methods of mathematical statistics, probability theory and methods of matrix calculation. The novelty of this model is that it allows to predict the change of the output characteristic in time, and the operating influences have been presented in an explicit form. As desirable dynamics of change of the output characteristic (function, reliability) the law of distribution of Veybull which is universal is adopted since at various values of parameters it turns into other types of distributions (for example, exponential, normal, etc.) It should be noted that the choice of the desirable law of management allows to determine the necessary management parameters with use of the saved-up change of the output characteristic in general. The output characteristic can be changed both on the speed of change of management parameters, and on acceleration of change of management parameters. In this article the technique of an assessment of the pseudo-return matrix has been stated in detail by the method of the smallest squares and the standard Microsoft Excel functions. Also the technique of finding of the operating effects when finding restrictions both for the output characteristic, and on management parameters has been considered. In the article the order and the sequence of finding of management parameters has been stated. A concrete example of finding of the operating effects in the course of long-term operation of turbines has been shown.

Geosynchronous platform definition study. Volume 3: Geosynchronous mission characteristics

NASA Technical Reports Server (NTRS)

1973-01-01

The objectives of the study were to examine the nature of currently planned and new evolutionary geosynchronous programs, to analyze alternative ways of conducting missions, to establish concepts for new systems to support geosynchronous programs in an effective and economical manner, and to define the logistic support to carry out these programs. In order to meet these objectives, it was necessary to define and examine general geosynchronous mission characteristics and the potentially applicable electromagnetic spectrum characteristics. An organized compilation of these data is given with emphasis on the development and use of the data. Fundamental geosynchronous orbit time histories, mission profile characteristics, and delivery system characteristics are presented. In addition, electromagnetic spectrum utilization is discussed in terms of the usable frequency spectrum, the spectrum potentially available considering established frequency allocations, and the technology status as it affects the ability to operate within specific frequency bands.

Research on the Error Characteristics of a 110 kV Optical Voltage Transformer under Three Conditions: In the Laboratory, Off-Line in the Field and During On-Line Operation.

PubMed

Xiao, Xia; Hu, Haoliang; Xu, Yan; Lei, Min; Xiong, Qianzhu

2016-08-16

Optical voltage transformers (OVTs) have been applied in power systems. When performing accuracy performance tests of OVTs large differences exist between the electromagnetic environment and the temperature variation in the laboratory and on-site. Therefore, OVTs may display different error characteristics under different conditions. In this paper, OVT prototypes with typical structures were selected to be tested for the error characteristics with the same testing equipment and testing method. The basic accuracy, the additional error caused by temperature and the adjacent phase in the laboratory, the accuracy in the field off-line, and the real-time monitoring error during on-line operation were tested. The error characteristics under the three conditions-laboratory, in the field off-line and during on-site operation-were compared and analyzed. The results showed that the effect of the transportation process, electromagnetic environment and the adjacent phase on the accuracy of OVTs could be ignored for level 0.2, but the error characteristics of OVTs are dependent on the environmental temperature and are sensitive to the temperature gradient. The temperature characteristics during on-line operation were significantly superior to those observed in the laboratory.

Design study of superconducting magnets for a combustion magnetohydrodynamic /MHD/ generator

NASA Technical Reports Server (NTRS)

Thome, R. J.; Ayers, J. W.; Hrycaj, T. M.; Burkhart, J. A.

1978-01-01

Results are presented for a trade-off and preliminary design study on concepts of a superconducting magnet system for a combustion MHD generator test facility. The main objective is to gain insight into the magnitude of the project in terms of physical characteristics and cost. The net result of a first-phase evaluation of attractive design alternatives is to concentrate subsequent efforts on (1) a racetrack coil geometry with an operating temperature of 4.2 K, (2) a racetrack coil geometry with an operating temperature of 2.0 K, and (3) a rectangular saddle coil geometry with an operating temperature of 4.2 K. All three systems are to produce 8 T, and use NbTi superconductor and iron for field enhancement. Design characteristics of the three systems are described. It is shown that the racetrack and rectangular saddle coil geometries seem most suitable for this application, the former because of its simplicity and the latter because of its efficient use of material. Advantages of the rectangular saddle over the two other systems are stressed.

Surgical problems and complex procedures: issues for operative time in robotic totally endoscopic coronary artery bypass grafting.

PubMed

Wiedemann, Dominik; Bonaros, Nikolaos; Schachner, Thomas; Weidinger, Felix; Lehr, Eric J; Vesely, Mark; Bonatti, Johannes

2012-03-01

Robotically assisted totally endoscopic coronary artery bypass grafting (TECAB) is a viable option for closed chest coronary surgery, but it requires learning curves and longer operative times. This study evaluated the effect of extended operation times on the outcome of patients undergoing TECAB. From 2001 to 2009, 325 patients underwent TECAB with the da Vinci telemanipulation system. Correlations between operative times and preoperative, intraoperative, and early postoperative parameters were investigated. Receiver operating characteristic analysis was used to define the threshold of the procedure duration above which intensive care unit stay and ventilation time were prolonged. Demographic data, intraoperative and postoperative parameters, and survival data were compared. Patients with prolonged operative times more often underwent multivessel revascularization (P < .001) and beating-heart TECAB (P =.023). Other preoperative parameters were not associated with longer operative times. Incidences of technical difficulties and conversions (P < .001) were higher among patients with longer operative times. Prolonged intensive care unit stay, mechanical ventilation, hospital stay, and with requirement of blood products were associated with longer operative times. Receiver operating characteristic analysis showed operative times >445 minutes and >478 minutes to predict prolonged (>48 hours) intensive care unit stay and mechanical ventilation, respectively. Patients with procedures >478 minutes had longer hospital stays and higher perioperative morbidity and mortality. Kaplan-Meier analysis revealed decreased survival among patients with operative times >478 minutes. Multivessel revascularization and conversions lead to prolonged operative times in totally endoscopic coronary artery bypass grafting. Longer operative times significantly influence early postoperative and midterm outcomes. Copyright © 2012 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Flow Characterization of Severe Carotid Artery Stenosis in Pre- and Post-operative Phantoms by Using Magnetic Resonance Velocimetry

NASA Astrophysics Data System (ADS)

Ko, Seungbin; Song, Simon; Kim, Doosang

2016-11-01

It is remained unknown that the flow characteristics changes between pre- and post-operative severe carotid artery stenosis could affect the long-term patency or failure. However, in-vivo clinical experiments to uncover the flow details are far from bed-side due to limited measurement resolutions, blurring artifact, etc. We studied detailed flow characteristics of more than 75% severe carotid artery stenosis before and after surgical treatments. Real-size flow phantoms for 10 patients, who underwent carotid endarterectomy with patch/no patch closure, were prepared by using a 3D rapid-prototype machine from CT scanned images. The working fluid is a glycerin aqueous solution, and patient-specific pulsatile flows were applied to the phantoms, based on ultrasonic flow rate measurements. The flows were visualized with magnetic resonance velocimetry (MRV). The detailed flow characteristics are presented for both pre- and post-operative carotid arteries along with visualization data of 3 dimensional, 3 component velocity fields. This work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MSIP) (No. 2016R1A2B3009541).

Revenue management of air cargo service in theory and practice

NASA Astrophysics Data System (ADS)

Budiarto, S.; Putro, H. P.; Pradono, P.; Yudoko, G.

2018-05-01

This study examines the air cargo service by comparing existing theories from previous research with the conditions on the ground. The object of the study is focused on the freight forwarder and the airport management. This study reviews the models and results of previous research that will be summarized and used to identify any issues related to the characteristics of air cargo operational services, as well as observing and monitoring literature with airlines, shipping companies, and airport management to explore and see the gap between prior research and implementation of its process in the air cargo service. The first phase in this study is to provide an overview of the air cargo industry. The second phase analyzes the characteristic differences between air cargo services and air passenger operating services. And the third phase is a literary bibliography study of air cargo operations, where the focus is on the studies using quantitative models from the perspective of the object of the study, which is the optimization of revenue management on air cargo services. From the results of the study, which is based on the gap between theory and practice, new research opportunities which are related to management of air cargo service revenue in the form of model development are found by adding booking timelines aspects of cargo that can affect the revenue of cargo airline companies and airports.

Bus driver fatigue and stress issues study

DOT National Transportation Integrated Search

2001-02-01

Fatigue-related issues associated with motorcoach drivers differ from the issues faced by truck drivers because of the distinct nature of their jobs. For example, truck and motorcoach drivers deal with different vehicular operating characteristics, n...

Small City Transit Characteristics : an Overview

DOT National Transportation Integrated Search

1976-03-01

The report is based on information and operating data from thirteen small community transit systems which were studied as part of a larger project on small community transit and its potential. It summarizes organizational, institutional, and operatio...

SSME model, engine dynamic characteristics related to Pogo

NASA Technical Reports Server (NTRS)

1973-01-01

A linear model of the space shuttle main engine for use in Pogo studies was presented. A digital program is included from which engine transfer functions are determined relative to the engine operating level.

Characteristics and values of a British military nurse. International implications of War Zone qualitative research.

PubMed

Finnegan, Alan; Finnegan, Sara; McKenna, Hugh; McGhee, Stephen; Ricketts, Lynda; McCourt, Kath; Warren, Jem; Thomas, Mike

2016-01-01

Between 2001 and 2014, British military nurses served in Afghanistan caring for both Service personnel and local nationals of all ages. However, there have been few research studies assessing the effectiveness of the military nurses' operational role and no papers naming the core values and characteristics. This paper is from the only qualitative nursing study completed during this period where data was collected in the War Zone. To explore the characteristics and values that are intrinsic to military nurses in undertaking their operational role. A constructivist grounded theory was utilised. The authors designed the interview schedule, and then following a pilot study, conducted and transcribed the discussions. Informed consent and UK Ministry of Defence Research Ethical Committee approval was obtained. Camp Bastion Hospital, Afghanistan, in 2013. Semi-structured interviews were conducted with 18 British Armed Forces nurses. A theoretical model was developed that identifies the intrinsic characteristics and values required to be a military nurse. Nursing care delivered within the operational environment was perceived as outstanding. Nurses consciously detached themselves from any legal processes and treated each casualty as a vulnerable patient, resulting in care, compassion and dignity being provided for all patients, irrespective of their background, beliefs or affiliations. The study findings provide military nurses with a framework for a realistic personal development plan that will allow them to build upon their strengths as well as to identify and ameliorate potential areas of weakness. Placing nurses first, with a model that focusses on the requirements of a good nurse has the potential to lead to better patient care, and improve the quality of the tour for defence nurses. These findings have international implications and have the potential for transferability to any level of military or civilian nursing practice. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Characteristics of multilevel storage and switching dynamics in resistive switching cell of Al2O3/HfO2/Al2O3 sandwich structure

NASA Astrophysics Data System (ADS)

Liu, Jian; Yang, Huafeng; Ma, Zhongyuan; Chen, Kunji; Zhang, Xinxin; Huang, Xinfan; Oda, Shunri

2018-01-01

We reported an Al2O3/HfO2/Al2O3 sandwich structure resistive switching device with significant improvement of multilevel cell (MLC) operation capability, which exhibited that four stable and distinct resistance states (one low resistance state and three high resistance states) can be achieved by controlling the Reset stop voltages (V Reset-stop) during the Reset operation. The improved MLC operation capability can be attributed to the R HRS/R LRS ratio enhancement resulting from increasing of the series resistance and decreasing of leakage current by inserting two Al2O3 layers. For the high-speed switching applications, we studied the initial switching dynamics by using the measurements of the pulse width and amplitude dependence of Set and Reset switching characteristics. The results showed that under the same pulse amplitude conditions, the initial Set progress is faster than the initial Reset progress, which can be explained by thermal-assisted electric field induced rupture model in the oxygen vacancies conductive filament. Thus, proper combination of varying pulse amplitude and width can help us to optimize the device operation parameters. Moreover, the device demonstrated ultrafast program/erase speed (10 ns) and good pulse switching endurance (105 cycles) characteristics, which are suitable for high-density and fast-speed nonvolatile memory applications.

Hazardous Waste Management System - Identification and Listing of Hazardous Waste - Toxicity Characteristic - Hydrocarbon Recovery Operations - Federal Register Notice, February 1, 1991

EPA Pesticide Factsheets

Extends the compliance date of the Toxicity Characteristic until January 25, 1991 for groundwater that is reinjected or reinfiltrated during existing hydrocarbon recovery operations at petroleum refineries, marketing terminals, and bulk plants.

Children's Comprehension of Metaphor: A Piagetian Interpretation

ERIC Educational Resources Information Center

Smith, J. W. A.

1976-01-01

When the descriptive interpretations that sixth and eighth graders provided for metaphors selected from fifth-grade readers were examined in a Piagetian framework, the poorest interpretations showed characteristics of concrete and pre-operational thought, while the best interpretations showed characteristics of formal operational thought. (RL)

Characteristics of membrane fouling in submerged membrane bioreactor under sub-critical flux operation.

PubMed

Su, Y C; Huang, C P; Pan, Jill R; Lee, H C

2008-01-01

Recently, the membrane bioreactor (MBR) process has become one of the novel technologies to enhance the performance of biological treatment of wastewater. Membrane bioreactor process uses the membrane unit to replace a sediment tank, and this can greatly enhance treatment performance. However, membrane fouling in MBR restricts its widespread application because it leads to permeate flux decline, making more frequent membrane cleaning and replacement necessary, which then increases operating and maintenance costs. This study investigated the sludge characteristics in membrane fouling under sub-critical flux operation and also assessed the effect of shear stress on membrane fouling. Membrane fouling was slow under sub-critical flux operation. However, as filamentous microbes became dominant in the reactor, membrane fouling increased dramatically due to the increased viscosity and polysaccharides. A close link was found between membrane fouling and the amount of polysaccharides in soluble EPS. The predominant resistance was the cake resistance which could be minimized by increasing the shear stress. However, the resistance of colloids and solutes was not apparently reduced by increasing shear stress. Therefore, smaller particles such as macromolecules (e.g. polysaccharides) may play an important role in membrane fouling under sub-critical flux operation.

Improvement in operational characteristics of KEPCO’s line-commutation-type superconducting hybrid fault current limiter

NASA Astrophysics Data System (ADS)

Yim, S.-W.; Park, B.-C.; Jeong, Y.-T.; Kim, Y.-J.; Yang, S.-E.; Kim, W.-S.; Kim, H.-R.; Du, H.-I.

2013-01-01

A 22.9 kV class hybrid fault current limiter (FCL) developed by Korea Electric Power Corporation and LS Industrial Systems in 2006 operates using the line commutation mechanism and begins to limit the fault current after the first half-cycle. The first peak of the fault current is available for protective coordination in the power system. However, it also produces a large electromagnetic force and imposes a huge stress on power facilities such as the main transformer and gas-insulated switchgear. In this study, we improved the operational characteristics of the hybrid FCL in order to reduce the first peak of the fault current. While maintaining the structure of the hybrid FCL system, we developed a superconducting module that detects and limits the fault current during the first half-cycle. To maintain the protective coordination capacity, the hybrid FCL was designed to reduce the first peak value of the fault current by up to approximately 30%. The superconducting module was also designed to produce a minimum AC loss, generating a small, uniform magnetic field distribution during normal operation. Performance tests confirmed that when applied to the hybrid FCL, the superconducting module showed successful current limiting operation without any damage.

[The clinical features and surgical treatment strategies of cervical kyphosis].

PubMed

Fang, Jia-hu; Jia, Lian-shun; Zhou, Xu-hui; Song, Li-jun; Cai, Wei-hua; Li, Xiang

2010-10-15

To analyze the clinical characteristics and the surgical treatment strategy of cervical kyphosis. From March 2006 to October 2009, 31 cases of cervical kyphosis were treated. According to the clinical features and imaging findings, different treatment methods were used. There were 9 patients in operation group, including 4 male and 5 female patients, aged from 17 to 72 years (average age of 35 years). Among them, 5 cases were idiopathic kyphosis and 4 cases were caused by laminectomy or other reasons. There were 22 patients in conservative treatment group, including 11 male and 11 female patients, aged from 14 to 40 years (average age of 29 years), who were all idiopathic cervical kyphosis. Before and 1 week after operation, clinical assessment were taken for the patients in operation group using Spinal Cord Injuries Classification Standard of American Spinal Injury Association (AISA). During the periodic review, the anteroposterior, normal sagittal films of cervical spine were taken. At 1 week and every 6 months after operation, MRI films were also taken. These films were studied to evaluate the effects of the operations. In the conservative group, assessment of treatment results by studying anteroposterior and normal lateral views of cervical spine were were taken every month. The clinical characteristics and the surgical treatment strategies of these patients were analyzed. In operation group, 9 cases were followed up for 6 to 18 months, all patients did not failed in internal fixation and fusion. AISA neurological score and neurological function significantly improved. Three days after operation the average Cobb angle was -1.29 ° (preoperative 54.24 °). In conservative group, the average Cobb angle was -5.41 ° (before treatment 11.20 °) 4 months after the treatment. The symptoms of neck shoulder and back pain disappeared, and all patients were followed up for 3 to 24 months, with no recurrence of symptoms. In the early period of cervical kyphosis, adopt postural therapy, plaster braces to correct an imbalance in cervical spine biomechanics can prevent deformity development. According to patients' clinical characteristics, choosing individual treatment programs can correct the severe cervical kyphosis and achieve good outcome.

Improving Reliability of Service Operation Using FMEA Review and New Opportunity for Investigations

NASA Astrophysics Data System (ADS)

Sutrisno, Agung; Gunawan, Indra

2016-01-01

Despite its growing contribution to the global economy, investigation on the application status of service FMEA study to support realization of reliable service operation is very limited in literature. Motivated by such situation, the paper presented an initial survey on the status and research gaps in developing and applying FMEA in service sectors. Systematic preliminary survey using specific criteria are undertaken. Our study indicated that development and application of service FMEA are partially addressing the characteristics of service operations and it is still applied into the good deed and profit oriented operations. Opportunities for further investigation pertaining to advancement of its decision supporting tool for service risk appraisal, its modification to cope with sustainability related requirements and application of service FMEA in not for profit oriented operations are presented as new avenues for further investigation

Concurrent airline fleet allocation and aircraft design with profit modeling for multiple airlines

NASA Astrophysics Data System (ADS)

Govindaraju, Parithi

A "System of Systems" (SoS) approach is particularly beneficial in analyzing complex large scale systems comprised of numerous independent systems -- each capable of independent operations in their own right -- that when brought in conjunction offer capabilities and performance beyond the constituents of the individual systems. The variable resource allocation problem is a type of SoS problem, which includes the allocation of "yet-to-be-designed" systems in addition to existing resources and systems. The methodology presented here expands upon earlier work that demonstrated a decomposition approach that sought to simultaneously design a new aircraft and allocate this new aircraft along with existing aircraft in an effort to meet passenger demand at minimum fleet level operating cost for a single airline. The result of this describes important characteristics of the new aircraft. The ticket price model developed and implemented here enables analysis of the system using profit maximization studies instead of cost minimization. A multiobjective problem formulation has been implemented to determine characteristics of a new aircraft that maximizes the profit of multiple airlines to recognize the fact that aircraft manufacturers sell their aircraft to multiple customers and seldom design aircraft customized to a single airline's operations. The route network characteristics of two simple airlines serve as the example problem for the initial studies. The resulting problem formulation is a mixed-integer nonlinear programming problem, which is typically difficult to solve. A sequential decomposition strategy is applied as a solution methodology by segregating the allocation (integer programming) and aircraft design (non-linear programming) subspaces. After solving a simple problem considering two airlines, the decomposition approach is then applied to two larger airline route networks representing actual airline operations in the year 2005. The decomposition strategy serves as a promising technique for future detailed analyses. Results from the profit maximization studies favor a smaller aircraft in terms of passenger capacity due to its higher yield generation capability on shorter routes while results from the cost minimization studies favor a larger aircraft due to its lower direct operating cost per seat mile.

Experimental investigation on the development characteristics of initial electrons in a gas pressurized closing switch under DC voltage

NASA Astrophysics Data System (ADS)

Rongxiao, ZHAI; Mengtong, QIU; Weixi, LUO; Peitian, CONG; Tao, HUANG; Jiahui, YIN; Tianyang, ZHANG

2018-04-01

As one of the most important elements in linear transformer driver (LTD) based systems, the gas pressurized closing switches are required to operate with a very low prefire probability during the DC-charging process to ensure reliable operation and stable output of the whole pulsed power system. The most direct and effective way to control the prefire probability is to select a suitable working coefficient. The study of the development characteristics of the initially generated electrons is useful for optimizing the working coefficient and improving the prefire characteristic of the switches. In this paper an ultraviolet pulsed laser is used to generate initial electrons inside the gap volume. A current measuring system is used to measure the time-dependent current generated by the growth of the initial electrons so as to study the development characteristics of the electrons under different working coefficients. Experimental results show that the development characteristics of the initial electrons are influenced obviously by the working coefficient. With the increase of the working coefficient, the development degree of the electrons increases consequently. At the same times, there is a threshold of working coefficient which produces the effect of ionization on electrons. The range of the threshold has a slow growth but remains close to 65% with the gas pressure increase. When the working coefficient increases further, γ processes are starting to be generated inside the gap volume. In addition, an optimal working coefficient beneficial for improving the prefire characteristic is indicated and further tested.

Experimental Investigation of Diffuser Pressure-ratio Control with Shock-positioning Limit on 28-inch Ram-jet Engine

NASA Technical Reports Server (NTRS)

Dunbar, William R; Wentworth, Carl B; Crowl, Robert J

1957-01-01

The performance of a control system designed for variable thrust applications was determined in an altitude free-jet facility at various Mach numbers, altitudes and angles of attack for a wide range of engine operation. The results are presented as transient response characteristics for step disturbances in fuel flow and stability characteristics as a function of control constants and engine operating conditions. The results indicate that the control is capable of successful operation over the range of conditions tested, although variations in engine gains preclude optimum response characteristics at all conditions with fixed control constants.

NASA/FAA/NCAR Supercooled Large Droplet Icing Flight Research: Summary of Winter 1996-1997 Flight Operations

NASA Technical Reports Server (NTRS)

Miller, Dean; Ratvasky, Thomas; Bernstein, Ben; McDonough, Frank; Strapp, J. Walter

1998-01-01

During the winter of 1996-1997, a flight research program was conducted at the NASA-Lewis Research Center to study the characteristics of Supercooled Large Droplets (SLD) within the Great Lakes region. This flight program was a joint effort between the National Aeronautics and Space Administration (NASA), the National Center for Atmospheric Research (NCAR), and the Federal Aviation Administration (FAA). Based on weather forecasts and real-time in-flight guidance provided by NCAR, the NASA-Lewis Icing Research Aircraft was flown to locations where conditions were believed to be conducive to the formation of Supercooled Large Droplets aloft. Onboard instrumentation was then used to record meteorological, ice accretion, and aero-performance characteristics encountered during the flight. A total of 29 icing research flights were conducted, during which "conventional" small droplet icing, SLD, and mixed phase conditions were encountered aloft. This paper will describe how flight operations were conducted, provide an operational summary of the flights, present selected experimental results from one typical research flight, and conclude with practical "lessons learned" from this first year of operation.

Making Progress as Leaders among University Staff

ERIC Educational Resources Information Center

Quah, Cheng Sim; Sim, Sandra Phek Lin

2014-01-01

This study examined the overview of how individuals in their respective teams operated and contributed to their organization. This study also identified the salient characteristics of how the respondents made progress as leaders in their respective faculties or departments towards identifying directions for innovative future practice through…

The Clubhouse as an Empowering Setting

ERIC Educational Resources Information Center

Mowbray, Carol T.; Lewandowski, Lisa; Holter, Mark; Bybee, Deborah

2006-01-01

Attention to psychosocial rehabilitation (PSR) practice has expanded in recent years. However, social work research studies on PSR are not numerous. This study focuses on operational characteristics of clubhouses, a major PSR program model, and the organizational attributes (including resource levels) that predict the extent to which the clubhouse…

Getting the Command and Control Right: A Vietnam Case Study

DTIC Science & Technology

2013-05-23

characteristics of universality. Although the term operational art is relatively new to military doctrine, the concept of synchronization, which...OPERATION URGENT FURY in Granada and while conducting military intervention in Lebanon. Military actions in Granada and Lebanon occurred in 1983. For more...Asia were General John K. Waters , commander of U.S. Army Pacific (USARPAC), General Hunter Harris Jr., Commander-in-Chief Pacific Air Force (CINCPACAF

Managing Workload in Human-Robot Interaction: A Review of Empirical Studies

DTIC Science & Technology

2010-01-01

central concern in determining successful teleoperation. Regardless of the sophistication of the technology, a robot is oper- ated – with different levels...by many characteristics, including the type of workload manipulation, the apparatus used, task char- acteristics, and/or type of outcome measures . Due...linguistic patterns. Further- more, this interference may not even be detected if operators do not explicitly measure team communication performance, or re

Better Assessment of Operational Suitability. Volume 2. Case Studies

DTIC Science & Technology

1992-01-01

August to 25 October 1988. Although declared operationally effective and suitable by OTEA, a Corrective Action Plan (CAP) was instituted on 5 December 1988...to correct performance deficiencies encountered in FOT&E. The option year 3 procureiaent was exercised on 8 December 1988. An OTEA assessment of the...Hughes developed and tested airframe design modifications to correct deficiencies noted in DT POT I, to improve flight handling characteristics, and to

Diagnosis of incidental gallbladder cancer after laparoscopic cholecystectomy: our experience

PubMed Central

2013-01-01

Background Gallbladder carcinoma is a rare high malignancy neoplasm. The incidence of intra or post-operative incidental gallbladder carcinoma diagnosis is estimated between 0,2 and 2,8%. Primary aim of our study is to evaluate incidental gallbladder carcinoma's incidence in our experience. Methods We retrospectively reviewed our Surgery Division's experience about the totality of laparoscopic cholecystectomies with post-operative histological evidence of incidental gallbladder cancer. We evaluated patients' characteristics, surgical related variables, histological response, surgivcal radicalization characteristics and surgical outcome. Results In the considered sample we observed 7 accidental gallbladder adenocarcinomas in post-operative histological examination. Pathological results were:1 pT1b N0 (G1), 2 pT2 N0 (G2), 2 pT2 N1 (G3b), 2 pT3 N1 (G3b) (Table 1). In 5 cases we performed neoplasm radicalization surgery with standard procedure revision. Two patients died before radicalization. Median global survival was 34 months. Conclusion With the increase of laparoscopic cholecystectomies both elective and urgent performed in our centre we observed also an increase of incidentally diagnosed gallbladder neoplasms. Early diagnosis, meticulous peri-operative study and accurate surgical strategy are essential factors to obtain good results in incidental gallbladder cancer. PMID:24268097

Hazardous Waste Management System - Identification and Listing of Hazardous Waste - Toxicity Characteristic - Hydrocarbon Recovery Operations - Federal Register Notice, April 2, 1991

EPA Pesticide Factsheets

Proposal to extend the compliance date for the Toxicity Characteristic until January 25, 1993 for produced groundwater from free phase hydrocarbon recovery operations at certain petroleum industry sites-namely, refineries, marketing terminals, bulk plants.

[Psychophysiological aspects of naval aviation pilots of the Navy in the operation of highly carrier-based aircraft].

PubMed

Mel'nik, S G; Chulaevskiĭ, A O

2011-08-01

The authors have shown that the most difficult elements of the flight deck of the ship are springboard takeoff and aerofinishing landing. An important task is to study the aerodynamic characteristics of the behavior of the aircraft during takeoff different characteristics, forming crews ready to act in particular situations. Adverse factors are the operating conditions of habitability of aircraft (noise, vibration, fumes in the air at work, and aircraft engines, etc.) that have a significant impact on the life of air crew and engineering staff. It is concluded that the development and use of effective means of protecting the organism from the effect of these factors is a priority for specialists in aviation medicine.

New modeling method for the dielectric relaxation of a DRAM cell capacitor

NASA Astrophysics Data System (ADS)

Choi, Sujin; Sun, Wookyung; Shin, Hyungsoon

2018-02-01

This study proposes a new method for automatically synthesizing the equivalent circuit of the dielectric relaxation (DR) characteristic in dynamic random access memory (DRAM) without frequency dependent capacitance measurement. Charge loss due to DR can be observed by a voltage drop at the storage node and this phenomenon can be analyzed by an equivalent circuit. The Havariliak-Negami model is used to accurately determine the electrical characteristic parameters of an equivalent circuit. The DRAM sensing operation is performed in HSPICE simulations to verify this new method. The simulation demonstrates that the storage node voltage drop resulting from DR and the reduction in the sensing voltage margin, which has a critical impact on DRAM read operation, can be accurately estimated using this new method.

Operational Characteristics of an SCR-Based Pulse Generating Circuit

DTIC Science & Technology

2014-12-01

of OUTC can further be explained by the RC time constants involved in the charging and discharging of OUTC during each pulse . When the SCR is...CHARACTERISTICS OF AN SCR-BASED PULSE GENERATING CIRCUIT by Wing Chien Christopher Chang December 2014 Thesis Advisor: Gamani Karunasiri Co...COVERED December 20 14 Master ’s Thesis 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS OPERATIONAL CHARACTERISTICS OF AN SCR-BASED PULSE GENERATING CIRCUIT 6

What Is Lean Management in Health Care? Development of an Operational Definition for a Cochrane Systematic Review.

PubMed

Rotter, Thomas; Plishka, Christopher; Lawal, Adegboyega; Harrison, Liz; Sari, Nazmi; Goodridge, Donna; Flynn, Rachel; Chan, James; Fiander, Michelle; Poksinska, Bonnie; Willoughby, Keith; Kinsman, Leigh

2018-01-01

Industrial improvement approaches such as Lean management are increasingly being adopted in health care. Synthesis is necessary to ensure these approaches are evidence based and requires operationalization of concepts to ensure all relevant studies are included. This article outlines the process utilized to develop an operational definition of Lean in health care. The literature search, screening, data extraction, and data synthesis processes followed the recommendations outlined by the Cochrane Collaboration. Development of the operational definition utilized the methods prescribed by Kinsman et al. and Wieland et al. This involved extracting characteristics of Lean, synthesizing similar components to establish an operational definition, applying this definition, and updating the definition to address shortcomings. We identified two defining characteristics of Lean health-care management: (1) Lean philosophy, consisting of Lean principles and continuous improvement, and (2) Lean activities, which include Lean assessment activities and Lean improvement activities. The resulting operational definition requires that an organization or subunit of an organization had integrated Lean philosophy into the organization's mandate, guidelines, or policies and utilized at least one Lean assessment activity or Lean improvement activity. This operational definition of Lean management in health care will act as an objective screening criterion for our systematic review. To our knowledge, this is the first evidence-based operational definition of Lean management in health care.

Capillary Two-Phase Thermal Devices for Space Applications

NASA Technical Reports Server (NTRS)

Ku, Jentung

2016-01-01

This is the presentation file for an invited seminar for Department of Mechanical and Aerospace Engineering at the Case Western Reserve University. The seminar is scheduled for April 1, 2016.Description: This presentation will discuss operating principles and performance characteristics of heat pipes (HPs) and loop heat pipes (LHPs) and their application for spacecraft thermal control. Topics include: 1) HP operating principles; 2) HP performance characteristics; 3) LHP pressure profiles; 4) LHP operating temperature; 5) LHP operating temperature control; and 6) Examples of using HPs and LHPs on NASA flight projects.

Modal emissions modeling with real traffic data

DOT National Transportation Integrated Search

1999-01-01

This report details the use of a modal emissions model to estimate the relative emissions of CO due to changes in vehicle operating characteristics on urban roadways. The Davis Institute for Transportation Studies Emissions Model (DITSEM) was selecte...

Sensitivity to imputation models and assumptions in receiver operating characteristic analysis with incomplete data

PubMed Central

Karakaya, Jale; Karabulut, Erdem; Yucel, Recai M.

2015-01-01

Modern statistical methods using incomplete data have been increasingly applied in a wide variety of substantive problems. Similarly, receiver operating characteristic (ROC) analysis, a method used in evaluating diagnostic tests or biomarkers in medical research, has also been increasingly popular problem in both its development and application. While missing-data methods have been applied in ROC analysis, the impact of model mis-specification and/or assumptions (e.g. missing at random) underlying the missing data has not been thoroughly studied. In this work, we study the performance of multiple imputation (MI) inference in ROC analysis. Particularly, we investigate parametric and non-parametric techniques for MI inference under common missingness mechanisms. Depending on the coherency of the imputation model with the underlying data generation mechanism, our results show that MI generally leads to well-calibrated inferences under ignorable missingness mechanisms. PMID:26379316

Estimation of dynamic stability parameters from drop model flight tests

NASA Technical Reports Server (NTRS)

Chambers, J. R.; Iliff, K. W.

1981-01-01

A recent NASA application of a remotely-piloted drop model to studies of the high angle-of-attack and spinning characteristics of a fighter configuration has provided an opportunity to evaluate and develop parameter estimation methods for the complex aerodynamic environment associated with high angles of attack. The paper discusses the overall drop model operation including descriptions of the model, instrumentation, launch and recovery operations, piloting concept, and parameter identification methods used. Static and dynamic stability derivatives were obtained for an angle-of-attack range from -20 deg to 53 deg. The results of the study indicated that the variations of the estimates with angle of attack were consistent for most of the static derivatives, and the effects of configuration modifications to the model (such as nose strakes) were apparent in the static derivative estimates. The dynamic derivatives exhibited greater uncertainty levels than the static derivatives, possibly due to nonlinear aerodynamics, model response characteristics, or additional derivatives.

Constrained sheath optics for high thrust density, low specific impulse ion thrusters

NASA Technical Reports Server (NTRS)

Wilbur, Paul J.; Han, Jian-Zhang

1987-01-01

The results of an experimental study showing that a contoured, fine wire mesh attached to the screen grid can be used to control the divergence characteristics of ion beamlets produced at low net-to-total accelerating voltage ratios are presented. The influence of free and constrained-sheath optics systems on beamlet divergence characteristics are found to be similar in the operating regime investigated, but it was found that constrained-sheath optics systems can be operated at higher perveance levels than free-sheath ones. The concept of a fine wire interference probe that can be used to study ion beamlet focusing behavior is introduced. This probe is used to demonstrate beamlet focusing to a diameter about one hundreth of the screen grid extraction aperture diameter. Additional testing is suggested to define an optimally contoured mesh that could yield well focused beamlets at net-to-total accelerating voltage ratios below about 0.1.

Flexible alpha allocation strategies for confirmatory adaptive enrichment clinical trials with a prespecified subgroup.

PubMed

Sugitani, Toshifumi; Posch, Martin; Bretz, Frank; Koenig, Franz

2018-06-26

Adaptive enrichment designs have recently received considerable attention as they have the potential to make drug development process for personalized medicine more efficient. Several statistical approaches have been proposed so far in the literature and the operating characteristics of these approaches are extensively investigated using simulation studies. In this paper, we improve on existing adaptive enrichment designs by assigning unequal weights to the significance levels associated with the hypotheses of the overall population and a prespecified subgroup. More specifically, we focus on the standard combination test, a modified combination test, the marginal combination test, and the partial conditional error rate approach and explore the operating characteristics of these approaches by a simulation study. We show that these approaches can lead to power gains, compared to existing approaches, if the weights are chosen carefully. © 2018 John Wiley & Sons, Ltd.

Radar/radiometer facilities for precipitation measurements

NASA Technical Reports Server (NTRS)

Hodge, D. B.; Taylor, R. C.

1973-01-01

The OSU ElectroScience Laboratory Radar/Radiometer Facilities are described. This instrumentation includes a high-resolution radar/radiometer system, a fully automated low-resolution radar system, and a small surveillance radar system. The high-resolution radar/radiometer system operates at 3, 9, and 15 GHz using two 9.1 m and one 4.6 m parabolic antennas, respectively. The low-resolution and surveillance radars operate at 9 and 15 GHz, respectively. Both the high- and low-resolution systems are interfaced to real-time digital processing and recording systems. This capability was developed for the measurement of the temporal and spatial characteristics of precipitation in conjunction with millimeter wavelength propagation studies utilizing the Advanced Technology Satellites. Precipitation characteristics derived from these measurements could also be of direct benefit in such diverse areas as: the atmospheric sciences, meteorology, water resources, flood control and warning, severe storm warning, agricultural crop studies, and urban and regional planning.

Sustainability of Social Programs: A Comparative Case Study Analysis

ERIC Educational Resources Information Center

Savaya, Riki; Spiro, Shimon; Elran-Barak, Roni

2008-01-01

The article reports on the findings of a comparative case study of six projects that operated in Israel between 1980 and 2000. The study findings identify characteristics of the programs, the host organizations, and the social and political environment, which differentiated programs that are sustained from those that are not. The findings reaffirm…

[The social hygiene problems in the operator work of hydroelectric power station workers and the means for enhancing work capacity].

PubMed

Karakashian, A N; Lepeshkina, T R; Ratushnaia, A N; Glushchenko, S S; Zakharenko, M I; Lastovchenko, V B; Diordichuk, T I

1993-01-01

Weight, tension and harmfulness of professional activity, peculiarities of labour conditions and characteristics of work, shift dynamics of operative personnel's working capacity were studied in the course of 8-hour working day currently accepted at hydroelectric power stations (HEPS) and experimental 12-hour schedule. Working conditions classified as "admissible", positive dynamics of operators' state, their social and material contentment were a basis for 12-hour two-shift schedule to be recommended as more appropriate. At the same time, problem of optimal shift schedules for operative personnel of HEPS remains unsolved and needs to be further explored.

Artificial neural network approach to predict surgical site infection after free-flap reconstruction in patients receiving surgery for head and neck cancer.

PubMed

Kuo, Pao-Jen; Wu, Shao-Chun; Chien, Peng-Chen; Chang, Shu-Shya; Rau, Cheng-Shyuan; Tai, Hsueh-Ling; Peng, Shu-Hui; Lin, Yi-Chun; Chen, Yi-Chun; Hsieh, Hsiao-Yun; Hsieh, Ching-Hua

2018-03-02

The aim of this study was to develop an effective surgical site infection (SSI) prediction model in patients receiving free-flap reconstruction after surgery for head and neck cancer using artificial neural network (ANN), and to compare its predictive power with that of conventional logistic regression (LR). There were 1,836 patients with 1,854 free-flap reconstructions and 438 postoperative SSIs in the dataset for analysis. They were randomly assigned tin ratio of 7:3 into a training set and a test set. Based on comprehensive characteristics of patients and diseases in the absence or presence of operative data, prediction of SSI was performed at two time points (pre-operatively and post-operatively) with a feed-forward ANN and the LR models. In addition to the calculated accuracy, sensitivity, and specificity, the predictive performance of ANN and LR were assessed based on area under the curve (AUC) measures of receiver operator characteristic curves and Brier score. ANN had a significantly higher AUC (0.892) of post-operative prediction and AUC (0.808) of pre-operative prediction than LR (both P <0.0001). In addition, there was significant higher AUC of post-operative prediction than pre-operative prediction by ANN (p<0.0001). With the highest AUC and the lowest Brier score (0.090), the post-operative prediction by ANN had the highest overall predictive performance. The post-operative prediction by ANN had the highest overall performance in predicting SSI after free-flap reconstruction in patients receiving surgery for head and neck cancer.

[The value of methods for morphofunctional analysis of cornea in cataract surgery].

PubMed

Borodina, N B; Kobzova, M V; Musaeva, G M

2011-01-01

The characteristics of morphofunctional status of cornea after extracapsular cataract extraction and phakoemulsification with IOL implantation (30 and 58 operations respectively) were analyzed in detail using up-to-date diagnostic techniques. The results of examination using developed algorithm including study of light transmission, refraction and protective function of cornea show advantage of microinvasive ultrasound technique of cataract surgery in terms of minimal impact on corneal structure, optical and biomechanical characteristics.

Research and design of logistical information system based on SOA

NASA Astrophysics Data System (ADS)

Zhang, Bo

2013-03-01

Through the study on the existing logistics information systems and SOA technology, based on the current situation of enterprise logistics management and business features, this paper puts forward a SOA-based logistics system design program. This program is made in the WCF framework, with the combination of SOA and the actual characteristics of logistics enterprises, is simple to realize, easy to operate, and has strong expansion characteristic, therefore has high practical value.

Human dynamics scaling characteristics for aerial inbound logistics operation

NASA Astrophysics Data System (ADS)

Wang, Qing; Guo, Jin-Li

2010-05-01

In recent years, the study of power-law scaling characteristics of real-life networks has attracted much interest from scholars; it deviates from the Poisson process. In this paper, we take the whole process of aerial inbound operation in a logistics company as the empirical object. The main aim of this work is to study the statistical scaling characteristics of the task-restricted work patterns. We found that the statistical variables have the scaling characteristics of unimodal distribution with a power-law tail in five statistical distributions - that is to say, there obviously exists a peak in each distribution, the shape of the left part closes to a Poisson distribution, and the right part has a heavy-tailed scaling statistics. Furthermore, to our surprise, there is only one distribution where the right parts can be approximated by the power-law form with exponent α=1.50. Others are bigger than 1.50 (three of four are about 2.50, one of four is about 3.00). We then obtain two inferences based on these empirical results: first, the human behaviors probably both close to the Poisson statistics and power-law distributions on certain levels, and the human-computer interaction behaviors may be the most common in the logistics operational areas, even in the whole task-restricted work pattern areas. Second, the hypothesis in Vázquez et al. (2006) [A. Vázquez, J. G. Oliveira, Z. Dezsö, K.-I. Goh, I. Kondor, A.-L. Barabási. Modeling burst and heavy tails in human dynamics, Phys. Rev. E 73 (2006) 036127] is probably not sufficient; it claimed that human dynamics can be classified as two discrete university classes. There may be a new human dynamics mechanism that is different from the classical Barabási models.

Appropriateness of Prescriptions of Recommended Treatments in Organisation for Economic Co-operation and Development Health Systems: Findings Based on the Long-Term Registry of the European Society of Cardiology on Heart Failure.

PubMed

Maggioni, Aldo P; Van Gool, Kees; Biondi, Nelly; Urso, Renato; Klazinga, Niek; Ferrari, Roberto; Maniadakis, Nikolaos; Tavazzi, Luigi

2015-12-01

This observational study aimed to identify clinical variables and health system characteristics associated with incomplete guideline application in drug treatment of patients with chronic heart failure (HF) across 15 countries. Three data sets were used: European Society of Cardiology Heart Failure Registry, Organisation for Economic Co-operation and Development's Health System Characteristics Survey, and Organisation for Economic Co-operation and Development Health Statistics 2013. Patient and country variables were examined by multilevel, multiple logistic regression. The study population consisted of ambulatory patients with chronic HF and reduced ejection fraction. Inappropriateness of prescription of pharmacological treatments was defined as patients not prescribed at least one of the two recommended treatments (angiotensin-converting enzyme inhibitors/angiotensin-receptor blockers and beta-blockers) or treated with both medications but at suboptimal dosage and in absence of documented contraindication/intolerance. Of 4605 patients, 1097 (23.8%) received inappropriate drug prescriptions with a large variation within and across countries, with 18.5% of the total variability accounted for by between-country health structure characteristics. Patient-level characteristics such as having mitral regurgitation (odds ratio 1.4; 95% confidence interval 1.1-1.7) was significantly associated with inappropriate prescription of recommended drugs, whereas chronic obstructive pulmonary disease (odds ratio 0.7; 95% confidence interval 0.5-0.9) was associated with more appropriate prescriptions. Among the country-level variables, incentives or obligation to comply with guidelines increased the probability of prescription appropriateness. Combining clinical variables with health system characteristics is a promising exercise to explain the appropriateness of recommended drug prescriptions. Such an understanding can help decision makers to design more effective policies to improve adherence to guidelines, improve health care outcomes, and potentially reduce costs. Copyright © 2015. Published by Elsevier Inc.

Health regionalization in Amazonas: progress and challenges.

PubMed

Garnelo, Luiza; Sousa, Amandia Braga Lima; Silva, Clayton de Oliveira da

2017-04-01

This paper analyses the health services regionalization process in the State of Amazonas through a case study covering the health sub-region Manaus Surroundings. This is a qualitative, descriptive and analytical research, which data were collected using interviews, documents and Internet reviews, oriented by the guiding concept of health regionalization. Study findings revealed a social setting dominated by asymmetry, verticality, competitiveness and fragile multilateral relations among municipalities, associated to a bureaucratic profile of local institutions operating in the region under study. The political agents have limited acknowledgement of the sociopolitical and institutional conditions in which they operate. They usually impute healthcare networks' management and operational issues to the natural and geographical characteristics of the Amazon region, but their financing, governance and technical capacity are insufficient to overcome them.

Investigation on discharge characteristics of a coaxial dielectric barrier discharge reactor driven by AC and ns power sources

NASA Astrophysics Data System (ADS)

Qian, WANG; Feng, LIU; Chuanrun, MIAO; Bing, YAN; Zhi, FANG

2018-03-01

A coaxial dielectric barrier discharge (DBD) reactor with double layer dielectric barriers has been developed for exhaust gas treatment and excited either by AC power or nanosecond (ns) pulse to generate atmospheric pressure plasma. The comparative study on the discharge characteristics of the discharge uniformity, power deposition, energy efficiency, and operation temperature between AC and ns pulsed coaxial DBD is carried out in terms of optical and electrical characteristics and operation temperature for optimizing the coaxial DBD reactor performance. The voltages across the air gap and dielectric layer and the conduction and displacement currents are extracted from the applied voltages and measured currents of AC and ns pulsed coaxial DBDs for the calculation of the power depositions and energy efficiencies through an equivalent electrical model. The discharge uniformity and operating temperature of the coaxial DBD reactor are monitored and analyzed by optical images and infrared camera. A heat conduction model is used to calculate the temperature of the internal quartz tube. It is found that the ns pulsed coaxial DBD has a much higher instantaneous power deposition in plasma, a lower total power consumption, and a higher energy efficiency compared with that excited by AC power and is more homogeneous and stable. The temperature of the outside wall of the AC and ns pulse excited coaxial DBD reaches 158 °C and 64.3 °C after 900 s operation, respectively. The experimental results on the comparison of the discharge characteristics of coaxial DBDs excited by different powers are significant for understanding of the mechanism of DBDs, reducing energy loss, and optimizing the performance of coaxial DBD in industrial applications.

Assessing operating characteristics of CAD algorithms in the absence of a gold standard

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

Roy Choudhury, Kingshuk; Paik, David S.; Yi, Chin A.

2010-04-15

Purpose: The authors examine potential bias when using a reference reader panel as ''gold standard'' for estimating operating characteristics of CAD algorithms for detecting lesions. As an alternative, the authors propose latent class analysis (LCA), which does not require an external gold standard to evaluate diagnostic accuracy. Methods: A binomial model for multiple reader detections using different diagnostic protocols was constructed, assuming conditional independence of readings given true lesion status. Operating characteristics of all protocols were estimated by maximum likelihood LCA. Reader panel and LCA based estimates were compared using data simulated from the binomial model for a range ofmore » operating characteristics. LCA was applied to 36 thin section thoracic computed tomography data sets from the Lung Image Database Consortium (LIDC): Free search markings of four radiologists were compared to markings from four different CAD assisted radiologists. For real data, bootstrap-based resampling methods, which accommodate dependence in reader detections, are proposed to test of hypotheses of differences between detection protocols. Results: In simulation studies, reader panel based sensitivity estimates had an average relative bias (ARB) of -23% to -27%, significantly higher (p-value <0.0001) than LCA (ARB -2% to -6%). Specificity was well estimated by both reader panel (ARB -0.6% to -0.5%) and LCA (ARB 1.4%-0.5%). Among 1145 lesion candidates LIDC considered, LCA estimated sensitivity of reference readers (55%) was significantly lower (p-value 0.006) than CAD assisted readers' (68%). Average false positives per patient for reference readers (0.95) was not significantly lower (p-value 0.28) than CAD assisted readers' (1.27). Conclusions: Whereas a gold standard based on a consensus of readers may substantially bias sensitivity estimates, LCA may be a significantly more accurate and consistent means for evaluating diagnostic accuracy.« less

General Intelligence (g): Overview of a Complex Construct and Its Implications for Genetics Research.

PubMed

Plucker, Jonathan A; Shelton, Amy L

2015-01-01

Current technology has dramatically increased the prevalence of studies to establish the genetic correlates of a wide variety of human characteristics, including not only the physical attributes that determine what we look like and the risk of physiological disease but also the psychological and cognitive characteristics that often define who we are as individuals. Perhaps one of the most deeply personal and often controversial characteristics is the concept of general intelligence, known in the psychological literature as "g." As with the genetic study of any complex trait, the first step in studying the genetics of g is to carefully define the characteristic of interest. For g, this entails establishing what intelligence means and providing a clear operational definition for how it will be measured. In this paper, we provide a brief historical and theoretical overview of the construct of general intelligence, describe its relationship to the contemporary measurement of intelligence, and discuss these concepts in light of the challenges associated with defining g as a characteristic in the study of genetics. © 2015 The Hastings Center.

Hazardous Waste Management System - Identification and Listing of Hazardous Waste - Toxicity Characteristic - Hydrocarbon Recovery Operations - Federal Register Notice, October 5, 1990

EPA Pesticide Factsheets

The Agency is promulgating an interim final rule to extend the compliance date of the Toxicity Characteristic rule for petroleum refining facilities, marketing terminals and bulk plants engaged in the recovery and remediation operation for 120 days.

30 CFR 250.407 - What tests must I conduct to determine reservoir characteristics?

Code of Federal Regulations, 2010 CFR

2010-07-01

... reservoir characteristics? 250.407 Section 250.407 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations General Requirements § 250.407 What tests must I conduct to determine...

Modeling of Multi-Tube Pulse Detonation Engine Operation

NASA Technical Reports Server (NTRS)

Ebrahimi, Houshang B.; Mohanraj, Rajendran; Merkle, Charles L.

2001-01-01

The present paper explores some preliminary issues concerning the operational characteristics of multiple-tube pulsed detonation engines (PDEs). The study is based on a two-dimensional analysis of the first-pulse operation of two detonation tubes exhausting through a common nozzle. Computations are first performed to assess isolated tube behavior followed by results for multi-tube flow phenomena. The computations are based on an eight-species, finite-rate transient flow-field model. The results serve as an important precursor to understanding appropriate propellant fill procedures and shock wave propagation in multi-tube, multi-dimensional simulations. Differences in behavior between single and multi-tube PDE models are discussed, The influence of multi-tube geometry and the preferred times for injecting the fresh propellant mixture during multi-tube PDE operation are studied.

Laparoscopic sleeve gastrectomy in patients with abdominoplasty: a case-control study.

PubMed

Saber, Alan A; Shoar, Saeed; El-Matbouly, Moamena; Karem, Mohsen; Bashah, Moataz M; Al Najjar, Ahmad; Alkuwari, Mohammad J; Soltanian, Hooman

2017-02-01

Abdominoplasty is increasingly performed after weight loss surgery. However, performing a laparoscopic sleeve gastrectomy (LSG) after abdominoplasty poses technical challenges. The present study aimed to compare operative events and postoperative outcomes between LSG patients with and without a history of prior abdominoplasty. University hospital, Qatar. A case-control study was conducted on 2 groups of patients with (n = 33) and without (n = 69) prior abdominoplasty who underwent LSG. Patient demographics, baseline characteristics, as well as operative and postoperative events were compared between the 2 groups. A total of 102 patients with an average age of 39.6±7.7 years and body mass index (BMI) of 42.8±5.9 kg/m 2 were included. There were no significant differences between the 2 groups in terms of demographic characteristics, preoperative BMI, and co-morbidities. The number of ports required was significantly higher in the LSG patients with a history of prior abdominoplasty than in the nonabdominoplasty patients. The operation time was also significantly longer in the abdominoplasty patients than in the nonabdominoplasty patients (90.3±36.7 minutes versus 57.1±17.7 minutes; P<.0001). However, no significant differences were observed in terms of postoperative complications, length of hospital stay, and weight loss results. LSG after abdominoplasty is associated with longer operative times and the need for additional port placement to overcome the decreased working space. However, operative strategies should be considered to overcome the technical challenges during LSG in patients who underwent a prior abdominoplasty. Copyright © 2017. Published by Elsevier Inc.

A Practice-Oriented Bifurcation Analysis for Pulse Energy Converters. Part 2: An Operating Regime

NASA Astrophysics Data System (ADS)

Kolokolov, Yury; Monovskaya, Anna

The paper continues the discussion on bifurcation analysis for applications in practice-oriented solutions for pulse energy conversion systems (PEC-systems). Since a PEC-system represents a nonlinear object with a variable structure, then the description of its dynamics evolution involves bifurcation analysis conceptions. This means the necessity to resolve the conflict-of-units between the notions used to describe natural evolution (i.e. evolution of the operating process towards nonoperating processes and vice versa) and the notions used to describe a desirable artificial regime (i.e. an operating regime). We consider cause-effect relations in the following sequence: nonlinear dynamics-output signal-operating characteristics, where these characteristics include stability and performance. Then regularities of nonlinear dynamics should be translated into regularities of the output signal dynamics, and, after, into an evolutional picture of each operating characteristic. In order to make the translation without losses, we first take into account heterogeneous properties within the structures of the operating process in the parametrical (P-) and phase (X-) spaces, and analyze regularities of the operating stability and performance on the common basis by use of the modified bifurcation diagrams built in joint PX-space. Then, the correspondence between causes (degradation of the operating process stability) and effects (changes of the operating characteristics) is decomposed into three groups of abnormalities: conditionally unavoidable abnormalities (CU-abnormalities); conditionally probable abnormalities (CP-abnormalities); conditionally regular abnormalities (CR-abnormalities). Within each of these groups the evolutional homogeneity is retained. After, the resultant evolution of each operating characteristic is naturally aggregated through the superposition of cause-effect relations in accordance with each of the abnormalities. We demonstrate that the practice-oriented bifurcation analysis has fundamentally specific purposes and tools, like for the computer-based bifurcation analysis and the experimental bifurcation analysis. That is why, from our viewpoint, it seems to be a rather novel direction in the general context of bifurcation analysis conceptions. We believe that the discussion could be interesting to pioneer research intended for the design of promising systems of pulse energy conversion.

Note: An improved solenoid driver valve for miniature shock tubes.

PubMed

Lynch, P T

2016-05-01

A solenoid driver valve has been built to improve the operating performance of diaphragmless shock tubes, which are used for high pressure, high temperature chemical kinetics, and fluid mechanics studies. For shock tube driver application, the most important characteristics are those of sealing, strength, and quality of the generated shock waves and repeatability of opening characteristics and therefore subsequent post-shock conditions. The main features of the new driver valve are a face o-ring sealing design of the valve, the large internal volume, and through inserts near the solenoid core: adjustable opening characteristics of the valve.

Space Shuttle Plume and Plume Impingement Study

NASA Technical Reports Server (NTRS)

Tevepaugh, J. A.; Penny, M. M.

1977-01-01

The extent of the influence of the propulsion system exhaust plumes on the vehicle performance and control characteristics is a complex function of vehicle geometry, propulsion system geometry, engine operating conditions and vehicle flight trajectory were investigated. Analytical support of the plume technology test program was directed at the two latter problem areas: (1) definition of the full-scale exhaust plume characteristics, (2) application of appropriate similarity parameters; and (3) analysis of wind tunnel test data. Verification of the two-phase plume and plume impingement models was directed toward the definition of the full-scale exhaust plume characteristics and the separation motor impingement problem.

Dynamic characteristics of 4H-SiC drift step recovery diodes

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

Ivanov, P. A., E-mail: Pavel.Ivanov@mail.ioffe.ru; Kon’kov, O. I.; Samsonova, T. P.

The dynamic characteristics of 4H-SiC p{sup +}–p–n{sub 0}–n{sup +} diodes are experimentally studied in the pulsed modes characteristic of the operation of drift step recovery diodes (DSRD-mode). The effect of the subnanosecond termination of the reverse current maintained by electron-hole plasma preliminarily pumped by a forward current pulse is analyzed in detail. The influence exerted on the DSRD effect by the amplitude of reverse-voltage pulses, the amplitude and duration of forward-current pulses, and the time delay between the forward and reverse pulses is demonstrated and accounted for.

Study of low density air transportation concepts

NASA Technical Reports Server (NTRS)

Webb, H. M.

1972-01-01

Low density air transport refers to air service to sparsely populated regions. There are two major objectives. The first is to examine those characteristics of sparsely populated areas which pertain to air transportation. This involves determination of geographical, commercial and population trends, as well as those traveler characteristics which affect the viability of air transport in the region. The second objective is to analyze the technical, economic and operational characteristics of low density air service. Two representative, but diverse arenas, West Virginia and Arizona, were selected for analysis: The results indicate that Arizona can support air service under certain assumptions whereas West Virginia cannot.

Automotive Fuel and Exhaust Systems.

ERIC Educational Resources Information Center

Irby, James F.; And Others

Materials are provided for a 14-hour course designed to introduce the automotive mechanic to the basic operations of automotive fuel and exhaust systems incorporated on military vehicles. The four study units cover characteristics of fuels, gasoline fuel system, diesel fuel systems, and exhaust system. Each study unit begins with a general…

Simulator Studies of the Deep Stall

NASA Technical Reports Server (NTRS)

White, Maurice D.; Cooper, George E.

1965-01-01

Simulator studies of the deep-stall problem encountered with modern airplanes are discussed. The results indicate that the basic deep-stall tendencies produced by aerodynamic characteristics are augmented by operational considerations. Because of control difficulties to be anticipated in the deep stall, it is desirable that adequate safeguards be provided against inadvertent penetrations.

Correlates of Mathematics Anxiety.

ERIC Educational Resources Information Center

McCoy, Leah P.

Learning is a complex operation that involves a several factors. In studying the learning process, both the characteristics of the learner and the conditions of instruction must be considered. This study examined some of the factors that may influence the learning of mathematics. In particular, it sought to identify relationships among mathematics…

Investigation of the Effects of Facility Background Pressure on the Performance and Voltage-Current Characteristics of the High Voltage Hall Accelerator

NASA Technical Reports Server (NTRS)

Kamhawi, Hani; Huang, Wensheng; Haag, Thomas; Spektor, Rostislav

2014-01-01

The National Aeronautics and Space Administration (NASA) Science Mission Directorate In-Space Propulsion Technology office is sponsoring NASA Glenn Research Center to develop a 4 kW-class Hall thruster propulsion system for implementation in NASA science missions. A study was conducted to assess the impact of varying the facility background pressure on the High Voltage Hall Accelerator (HiVHAc) thruster performance and voltage-current characteristics. This present study evaluated the HiVHAc thruster performance in the lowest attainable background pressure condition at NASA GRC Vacuum Facility 5 to best simulate space-like conditions. Additional tests were performed at selected thruster operating conditions to investigate and elucidate the underlying physics that change during thruster operation at elevated facility background pressure. Tests were performed at background pressure conditions that are three and ten times higher than the lowest realized background pressure. Results indicated that the thruster discharge specific impulse and efficiency increased with elevated facility background pressure. The voltage-current profiles indicated a narrower stable operating region with increased background pressure. Experimental observations of the thruster operation indicated that increasing the facility background pressure shifted the ionization and acceleration zones upstream towards the thruster's anode. Future tests of the HiVHAc thruster are planned at background pressure conditions that are expected to be two to three times lower than what was achieved during this test campaign. These tests will not only assess the impact of reduced facility background pressure on thruster performance, voltage-current characteristics, and plume properties; but will also attempt to quantify the magnitude of the ionization and acceleration zones upstream shifting as a function of increased background pressure.

Predicting Dural Tear in Compound Depressed Skull Fractures: A Prospective Multicenter Correlational Study.

PubMed

Salia, Shemsedin Musefa; Mersha, Hagos Biluts; Aklilu, Abenezer Tirsit; Baleh, Abat Sahlu; Lund-Johansen, Morten

2018-06-01

Compound depressed skull fracture (DSF) is a neurosurgical emergency. Preoperative knowledge of dural status is indispensable for treatment decision making. This study aimed to determine predictors of dural tear from clinical and imaging characteristics in patients with compound DSF. This prospective, multicenter correlational study in neurosurgical hospitals in Addis Ababa, Ethiopia, included 128 patients operated on from January 1, 2016, to October 31, 2016. Clinical, imaging, and intraoperative findings were evaluated. Univariate and multivariate analyses were used to establish predictors of dural tear. A logistic regression model was developed to predict probability of dural tear. Model validation was done using the receiver operating characteristic curve. Dural tear was seen in 55.5% of 128 patients. Demographics, injury mechanism, clinical presentation, and site of DSF had no significant correlation with dural tear. In univariate and multivariate analyses, depth of fracture depression (odds ratio 1.3, P < 0.001), pneumocephalus (odds ratio 2.8, P = 0.005), and brain contusions/intracerebral hematoma (odds ratio 5.5, P < 0.001) were significantly correlated with dural tear. We developed a logistic regression model (diagnostic test) to calculate probability of dural tear. Using the receiver operating characteristic curve, we determined the cutoff value for a positive test giving the highest accuracy to be 30% with a corresponding sensitivity of 93.0% and specificity of 43.9%. Dural tear in compound DSF can be predicted with 93.0% sensitivity using preoperative findings and may guide treatment decision making in resource-limited settings where risk of extensive cranial surgery outweighs the benefit. Copyright © 2018 Elsevier Inc. All rights reserved.

EFFECT OF FLOW CHARACTERISTICS ON DO DISTRIBUTION IN A FULL SCALE OXIDATION DITCH WITH DIFFUSED AERATION AND VERTICAL FLOW BOOSTERS

NASA Astrophysics Data System (ADS)

Nakamachi, Kazuo; Fujiwara, Taku; Kawaguchi, Yukio; Tsuno, Hiroshi

The high loading rate oxidation ditch (OD) system with dual dissolved oxygen (DO) control has been developed for the purpose of advanced wastewater treatment and cost saving. For the purpose of scale-up to the real scale, the clean water experiments were conducted, with the full scale oxidation ditch with diffused aeration and vertical flow boosters, to examine the effect to the dual DO control by the design and operational factors, which include a flow characteristics and a oxygen supply capability. In this study, the flow characteristics of the OD channel were analyzed using a tank number and circulation ratio as the parameters. The analysis showed the complicated flow characteristics of the OD channel, which changed from the plug flow to the completely mixing transiently. Based on the tank number N =65~100 which were obtained from the tracer tests, a model of DO mass balance was constructed, then the accurate method for estimate the overall oxygen transfer coefficients was proposed. The potential error of the conventional method in the specific conditions was indicated. In addition, the effect of the flow characteristics on the design and operational parameters of the dual DO control, which include the circulation time or the DO profile, was clarified.

Dependence of driving characteristics upon follower-leader combination

NASA Astrophysics Data System (ADS)

Nagahama, Akihito; Yanagisawa, Daichi; Nishinari, Katsuhiro

2017-10-01

The analysis of the microscopic view of mixed traffic offers a basis for resolving traffic jams which are inhomogeneous due to several types of vehicles. In this study, we research the dependence of driving characteristics upon vehicle order in a platoon. By focusing particularly upon the manner in which the driving characteristics of a follower are affected by both their own vehicle type and that of their leader, we measured the trajectories of platoons comprising two vehicles selected from motorcycles, passenger cars, and trucks on a test course. Analysis based on vehicle order showed that the vehicle types of both the leader and the follower as well as the leader's driving characteristics affected the velocity, acceleration, deceleration, operational delay of followers, and the distance gap between leaders and followers in different ways. In addition, we investigated the factors affecting driving characteristics by multiple regression analysis. We revealed that the operational delay and the maximum distance gap tend to be large when the length of leaders is large. Furthermore, as long as a follower can follow, we need not consider vehicle types among the parameters determining maximum velocity in car-following models. The vehicle types of the leader and the follower should be considered to determine maximum acceleration. When determining maximum deceleration, the vehicle types of the follower should be considered.

Positive direct current corona discharges in single wire-duct electrostatic precipitators

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

Yehia, Ashraf, E-mail: yehia30161@yahoo.com; Department of Physics, Faculty of Science, Assiut University, Assiut 71516, Arab Republic of Egypt; Abdel-Fattah, E.

This paper is aimed to study the characteristics of the positive dc corona discharges in single wire-duct electrostatic precipitators. Therefore, the corona discharges were formed inside dry air fed single wire-duct reactor under positive dc voltage at the normal atmospheric conditions. The corona current-voltage characteristics curves have been measured in parallel with the ozone concentration generated inside the reactor under different discharge conditions. The corona current-voltage characteristics curves have agreed with a semi empirical equation derived from the previous studies. The experimental results of the ozone concentration generated inside the reactor were formulated in the form of an empirical equationmore » included the different parameters that were studied experimentally. The obtained equations are valid to expect both the current-voltage characteristics curves and the corresponding ozone concentration that generates with the positive dc corona discharges inside single wire-duct electrostatic precipitators under any operating conditions in the same range of the present study.« less

Performance Demonstration of Mcmb-LiNiCoO2 Cells Containing Electrolytes Designed for Wide Operating Temperature Range

NASA Technical Reports Server (NTRS)

Smart, M. C.; Ratnakumar, B. V.; Whicanack, L. D.; Smith, K. A.; Santee, S.; Puglia, F. J.; Gitzendanner, R.

2009-01-01

With the intent of improving the performance of Li-ion cells over a wide operating temperature range, we have investigated the use of co-solvents to improve the properties of electrolyte formulations. In the current study, we have focused upon evaluating promising electrolytes which have been incorporated into large capacity (7 Ah) prototype Li-ion cells, fabricated by Yardney Technical Products, Inc. The electrolytes selected for performance evaluation include the use of a number of esters as co-solvents, including methyl propionate (MP), ethyl propionate (EP), ethyl butyrate (EB), propyl butyrate (PB), and 2,2,2-trifluoroethyl butyrate (TFEB). The performance of the prototype cells containing the ester-based electrolytes was compared with an extensive data base generated on cells containing previously developed all carbonate-based electrolytes. A number of performance tests were performed, including determining (i) the discharge rate capacity over a wide range of temperatures, (ii) the charge characteristics, (iii) the cycle life characteristics under various conditions, and (iv) the impedance characteristics.

The investigations of characteristics of Sb2Te as a base phase-change material

NASA Astrophysics Data System (ADS)

Liu, Guangyu; Wu, Liangcai; Zhu, Min; Song, Zhitang; Rao, Feng; Song, Sannian; Cheng, Yan

2017-09-01

Chalcogenide alloys are paid much attention in the study of nonvolatile phase-change memory (PCM). A comprehensive research is investigated on Sb2Te (ST), a base material, from properties to performances in this paper. For the characteristics of ST films, the sheet resistance is extremely stable during cooling process in resistance-temperature measurement and the thickness change of ST film is 5.7%. However, low 10-year data retention temperature (∼55 °C) and large crystal grain are the demerits for ST. In addition, the structure characteristics show stable hexagonal phase and large grain of several hundred nanometers at crystalline state after annealing. As for electrical properties, although the ST-based PCM devices are characterized by fast operation speed of ∼20 ns, only about 8 × 103 times of stable operation cycles can be obtained. After that, the endurance performance deteriorates gradually due to the growth of grains. About resistance drift, the drift coefficients are very small both in crystalline state and in amorphous state.

From raw material to dish: pasta quality step by step.

PubMed

Sicignano, Angelo; Di Monaco, Rossella; Masi, Paolo; Cavella, Silvana

2015-10-01

Pasta is a traditional Italian cereal-based food that is popular worldwide because of its convenience, versatility, sensory and nutritional value. The aim of this review is to present a step-by-step guide to facilitate the understanding of the most important events that can affect pasta characteristics, directing the reader to the appropriate production steps. Owing to its unique flavor, color, composition and rheological properties, durum wheat semolina is the best raw material for pasta production. Although pasta is traditionally made from only two ingredients, sensory quality and chemical/physical characteristics of the final product may vary greatly. Starting from the same ingredients, there are a lot of different events in each step of pasta production that can result in the development of varieties of pasta with different characteristics. In particular, numerous studies have demonstrated the importance of temperature and humidity conditions of the pasta drying operation as well as the significance of the choice of raw material and operating conditions on pasta quality. © 2015 Society of Chemical Industry.

Effect of Energy Input on the Characteristic of AISI H13 and D2 Tool Steels Deposited by a Directed Energy Deposition Process

NASA Astrophysics Data System (ADS)

Park, Jun Seok; Park, Joo Hyun; Lee, Min-Gyu; Sung, Ji Hyun; Cha, Kyoung Je; Kim, Da Hye

2016-05-01

Among the many additive manufacturing technologies, the directed energy deposition (DED) process has attracted significant attention because of the application of metal products. Metal deposited by the DED process has different properties than wrought metal because of the rapid solidification rate, the high thermal gradient between the deposited metal and substrate, etc. Additionally, many operating parameters, such as laser power, beam diameter, traverse speed, and powder mass flow rate, must be considered since the characteristics of the deposited metal are affected by the operating parameters. In the present study, the effect of energy input on the characteristics of H13 and D2 steels deposited by a direct metal tooling process based on the DED process was investigated. In particular, we report that the hardness of the deposited H13 and D2 steels decreased with increasing energy input, which we discuss by considering microstructural observations and thermodynamics.

Leadership and Characteristics of Nonprofit Mental Health Peer-Run Organizations Nationwide

PubMed Central

Ostrow, Laysha; Hayes, Stephania L.

2015-01-01

Objective Mental health peer-run organizations are nonprofits providing venues for support and advocacy among people diagnosed as having mental disorders. It has been proposed that consumer involvement is essential to their operations. This study reported organizational characteristics of peer-run organizations nationwide and how these organizations differ by degree of consumer control. Methods Data were from the 2012 National Survey of Peer-Run Organizations. The analyses described the characteristics of the organizations (N = 380) on five domains of nonprofit research, comparing results for organizations grouped by degree of involvement by consumers in the board of directors. Results Peer-run organizations provided a range of supports and educational and advocacy activities and varied in their capacity and resources. Some variation was explained by the degree of consumer control. Conclusions These organizations seemed to be operating consistently with evidence on peer-run models. The reach of peer-run organizations, and the need for in-depth research, continues to grow. PMID:25639988

Shooting Gallery Operation in the Context of Establishing a Medically Supervised Injecting Center: Sydney, Australia

PubMed Central

Dolan, Kate

2007-01-01

Shooting galleries (SGs) are illicit off-street spaces close to drug markets used for drug injection. Supervised injecting facilities (SIFs) are low threshold health services where injecting drug users (IDUs) can inject pre-obtained drugs under supervision. This study describes SG use in Kings Cross, Sydney before and after the opening of the Sydney Medically Supervised Injecting Centre (MSIC), Australia’s first SIF. Operational and environmental characteristics of SGs, reasons for SG use, and willingness to use MSIC were also examined. An exploratory survey of SG users (n = 31), interviews with SG users (n = 17), and drug workers (n = 8), and counts of used needles routinely collected from SGs (6 months before and after MSIC) and visits to the MSIC (6 months after MSIC) were triangulated. We found five SGs operated during the study period. Key operational characteristics were 24-h operation, AUS$10 entry fee, 30-min time limit, and dual use for sex work. Key reasons for SG use were to avoid police, a preference not to inject in public, and assistance from SG operators in case of overdose. SG users reported high levels of willingness to use the MSIC. The number of used needles collected from SGs decreased by 69% (41,819 vs. 12,935) in the 6 months after MSIC opened, while MSIC visits increased incrementally. We conclude that injections were transferred from SGs to the MSIC, but SGs continued to accommodate injections and harm reduction outreach should be maintained. PMID:17273925

Mass and number size distributions of emitted particulates at five important operation units in a hazardous industrial waste incineration plant.

PubMed

Lin, Chi-Chi; Huang, Hsiao-Lin; Hsiao, Wen-Yuan

2016-01-01

Past studies indicated particulates generated by waste incineration contain various hazardous compounds. The aerosol characteristics are very important for particulate hazard control and workers' protection. This study explores the detailed characteristics of emitted particulates from each important operation unit in a rotary kiln-based hazardous industrial waste incineration plant. A dust size analyzer (Grimm 1.109) and a scanning mobility particle sizer (SMPS) were used to measure the aerosol mass concentration, mass size distribution, and number size distribution at five operation units (S1-S5) during periods of normal operation, furnace shutdown, and annual maintenance. The place with the highest measured PM10 concentration was located at the area of fly ash discharge from air pollution control equipment (S5) during the period of normal operation. Fine particles (PM2.5) constituted the majority of the emitted particles from the incineration plant. The mass size distributions (elucidated) made it clear that the size of aerosols caused by the increased particulate mass, resulting from work activities, were mostly greater than 1.5 μm. Whereas the number size distributions showed that the major diameters of particulates that caused the increase of particulate number concentrations, from work activities, were distributed in the sub micrometer range. The process of discharging fly ash from air pollution control equipment can significantly increase the emission of nanoparticles. The mass concentrations and size distributions of emitted particulates were different at each operation unit. This information is valuable for managers to take appropriate strategy to reduce the particulate emission and associated worker exposure.

Inlet Flow Valve Engine Analyses

NASA Technical Reports Server (NTRS)

Champagne, G. A.

2004-01-01

Pratt&Whitney, under Task Order 13 of the NASA Large Engine Technology (LET) Contract, conducted a study to determine the operating characteristics, performance and weights of Inlet Flow Valve (IFV) propulsion concepts for a Mach 2.4 High Speed Civil Transport (HSCT).

Utility of hepatic transaminases in children with concern for abuse.

PubMed

Lindberg, Daniel M; Shapiro, Robert A; Blood, Emily A; Steiner, R Daryl; Berger, Rachel P

2013-02-01

Routine testing of hepatic transaminases, amylase, and lipase has been recommended for all children evaluated for physical abuse, but rates of screening are widely variable, even among abuse specialists, and data for amylase and lipase testing are lacking. A previous study of screening in centers that endorsed routine transaminase screening suggested that using a transaminase threshold of 80 IU/L could improve injury detection. Our objectives were to prospectively validate the test characteristics of the 80-IU/L threshold and to determine the utility of amylase and lipase to detect occult abdominal injury. This was a retrospective secondary analysis of the Examining Siblings To Recognize Abuse research network, a multicenter study in children younger than 10 years old who underwent subspecialty evaluation for physical abuse. We determined rates of identified abdominal injuries and results of transaminase, amylase, and lipase testing. Screening studies were compared by using basic test characteristics (sensitivity, specificity) and the area under the receiver operating characteristic curve. Abdominal injuries were identified in 82 of 2890 subjects (2.8%; 95% confidence interval: 2.3%-3.5%). Hepatic transaminases were obtained in 1538 (53%) subjects. Hepatic transaminases had an area under the receiver operating characteristic curve of 0.87. A threshold of 80 IU/L yielded sensitivity of 83.8% and specificity of 83.1%. The areas under the curve for amylase and lipase were 0.67 and 0.72, respectively. Children evaluated for physical abuse with transaminase levels >80 IU/L should undergo definitive testing for abdominal injury.

Turboprop cargo aircraft systems study

NASA Technical Reports Server (NTRS)

Muehlbauer, J. C.; Hewell, J. G., Jr.; Lindenbaum, S. P.; Randall, C. C.; Searle, N.; Stone, R. G., Jr.

1981-01-01

The effects of using advanced turboprop propulsion systems to reduce the fuel consumption and direct operating costs of cargo aircraft were studied, and the impact of these systems on aircraft noise and noise prints around a terminal area was determined. Parametric variations of aircraft and propeller characteristics were investigated to determine their effects on noiseprint areas, fuel consumption, and direct operating costs. From these results, three aircraft designs were selected and subjected to design refinements and sensitivity analyses. Three competitive turbofan aircraft were also defined from parametric studies to provide a basis for comparing the two types of propulsion.

Mechanical systems readiness assessment and performance monitoring study

NASA Technical Reports Server (NTRS)

1972-01-01

The problem of mechanical devices which lack the real-time readiness assessment and performance monitoring capability required for future space missions is studied. The results of a test program to establish the feasibility of implementing structure borne acoustics, a nondestructive test technique, are described. The program included the monitoring of operational acoustic signatures of five separate mechanical components, each possessing distinct sound characteristics. Acoustic signatures were established for normal operation of each component. Critical failure modes were then inserted into the test components, and faulted acoustic signatures obtained. Predominant features of the sound signature were related back to operational events occurring within the components both for normal and failure mode operations. All of these steps can be automated. The structure borne acoustics technique lends itself to reducing checkout time, simplifying maintenance procedures, and reducing manual involvement in the checkout, operation, maintenance, and fault diagnosis of mechanical systems.

Experimental characterization of a binary actuated parallel manipulator

NASA Astrophysics Data System (ADS)

Giuseppe, Carbone

2016-05-01

This paper describes the BAPAMAN (Binary Actuated Parallel MANipulator) series of parallel manipulators that has been conceived at Laboratory of Robotics and Mechatronics (LARM). Basic common characteristics of BAPAMAN series are described. In particular, it is outlined the use of a reduced number of active degrees of freedom, the use of design solutions with flexural joints and Shape Memory Alloy (SMA) actuators for achieving miniaturization, cost reduction and easy operation features. Given the peculiarities of BAPAMAN architecture, specific experimental tests have been proposed and carried out with the aim to validate the proposed design and to evaluate the practical operation performance and the characteristics of a built prototype, in particular, in terms of operation and workspace characteristics.

Establishment of key grid-connected performance index system for integrated PV-ES system

NASA Astrophysics Data System (ADS)

Li, Q.; Yuan, X. D.; Qi, Q.; Liu, H. M.

2016-08-01

In order to further promote integrated optimization operation of distributed new energy/ energy storage/ active load, this paper studies the integrated photovoltaic-energy storage (PV-ES) system which is connected with the distribution network, and analyzes typical structure and configuration selection for integrated PV-ES generation system. By combining practical grid- connected characteristics requirements and technology standard specification of photovoltaic generation system, this paper takes full account of energy storage system, and then proposes several new grid-connected performance indexes such as paralleled current sharing characteristic, parallel response consistency, adjusting characteristic, virtual moment of inertia characteristic, on- grid/off-grid switch characteristic, and so on. A comprehensive and feasible grid-connected performance index system is then established to support grid-connected performance testing on integrated PV-ES system.

Aeroacoustics of Flight Vehicles: Theory and Practice. Volume 2: Noise Control

NASA Technical Reports Server (NTRS)

Hubbard, Harvey H. (Editor)

1991-01-01

Flight vehicles and the underlying concepts of noise generation, noise propagation, noise prediction, and noise control are studied. This volume includes those chapters that relate to flight vehicle noise control and operations: human response to aircraft noise; atmospheric propagation; theoretical models for duct acoustic propagation and radiation; design and performance of duct acoustic treatment; jet noise suppression; interior noise; flyover noise measurement and prediction; and quiet aircraft design and operational characteristics.

Space Operations Center system analysis study extension. Volume 4, book 1: SOC system analysis report

NASA Technical Reports Server (NTRS)

1982-01-01

The Space Operations Center (SOC) orbital space station missions are analyzed. Telecommunications missions, space science, Earth sensing, and space testing missions, research and applications missions, defense missions, and satellite servicing missions are modeled and mission needs discussed. The satellite servicing missions are analyzed in detail, including construction and servicing equipment requirements, mission needs and benefits, differential drag characteristics of co-orbiting satellites, and satellite servicing transportation requirements.

2016 National Census of Ferry Operators [supporting datasets

DOT National Transportation Integrated Search

2018-03-06

The Bureau of Transportation Statistics (BTS) conducted the National Census of Ferry Operators (NCFO) from April through November 2016, collecting the operational characteristics of the 2015 calendar year ferry operations. : The supporting zip file c...

Accuracy of Point-of-care Ultrasonography for Diagnosing Acute Appendicitis: A Systematic Review and Meta-analysis.

PubMed

Matthew Fields, J; Davis, Joshua; Alsup, Carl; Bates, Amanda; Au, Arthur; Adhikari, Srikar; Farrell, Isaac

2017-09-01

The use of ultrasonography (US) to diagnose appendicitis is well established. More recently, point-of-care ultrasonography (POCUS) has also been studied for the diagnosis of appendicitis, which may also prove a valuable diagnostic tool. The purpose of this study was through systematic review and meta-analysis to identify the test characteristics of POCUS, specifically US performed by a nonradiologist physician, in accurately diagnosing acute appendicitis in patients of any age. We conducted a thorough and systematic literature search of English language articles published on point-of-care, physician-performed transabdominal US used for the diagnosis of acute appendicitis from 1980 to May, 2015 using OVID MEDLINE In-Process & Other Non-indexed Citations and Scopus. Studies were selected and subsequently independently abstracted by two trained reviewers. A random-effects pooled analysis was used to construct a hierarchical summary receiver operator characteristic curve, and a meta-regression was performed. Quality of studies was assessed using the QUADAS-2 tool. Our search yielded 5,792 unique studies and we included 21 of these in our final review. Prevalence of disease in this study was 29.8%, (range = 6.4%-75.4%). The sensitivity and specificity for POCUS in diagnosing appendicitis were 91% (95% confidence interval [CI] = 83%-96%) and 97% (95% CI = 91%-99%), respectively. The positive and negative predictive values were 91 and 94%, respectively. Studies performed by emergency physicians had slightly lower test characteristics (sensitivity = 80%, specificity = 92%). There was significant heterogeneity between studies (I 2 = 99%, 95% CI = 99%-100%) and the quality of the reported studies was moderate, mostly due to unclear reporting of blinding of physicians and timing of scanning and patient enrollment. Several of the studies were performed by a single operator, and the education and training of the operators were variably reported. Point-of-care US has relatively high sensitivity and specificity for diagnosing acute appendicitis, although the data presented are limited by the quality of the original studies and large CIs. In the hands of an experienced operator, POCUS is an appropriate initial imaging modality for diagnosing appendicitis. Based on our results, it is premature to utilize POCUS as a stand-alone test or to rule out appendicitis. © 2017 by the Society for Academic Emergency Medicine.

Farm Operating and Financial Characteristics, 1985. Statistical Bulletin Number 762.

ERIC Educational Resources Information Center

Morehart, Mitchell J.

This report contains 56 tables that provide an overview of the operating and financial characteristics of farms in the United States in 1985. The report provides information on farms and land in farms; farm acreage purchased, sold, and rented; farm labor and wages; capital investments and improvement; farm production expenses; farm and nonfarm…

30 CFR 250.407 - What tests must I conduct to determine reservoir characteristics?

Code of Federal Regulations, 2013 CFR

2013-07-01

... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations General Requirements § 250.407 What tests must I conduct to... characteristics of oil, gas, sulphur, and water in the formations penetrated by logging, formation sampling, or...

30 CFR 250.407 - What tests must I conduct to determine reservoir characteristics?

Code of Federal Regulations, 2012 CFR

2012-07-01

... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations General Requirements § 250.407 What tests must I conduct to... characteristics of oil, gas, sulphur, and water in the formations penetrated by logging, formation sampling, or...

30 CFR 250.407 - What tests must I conduct to determine reservoir characteristics?

Code of Federal Regulations, 2014 CFR

2014-07-01

... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations General Requirements § 250.407 What tests must I conduct to... characteristics of oil, gas, sulphur, and water in the formations penetrated by logging, formation sampling, or...

30 CFR 250.407 - What tests must I conduct to determine reservoir characteristics?

Code of Federal Regulations, 2011 CFR

2011-07-01

... reservoir characteristics? 250.407 Section 250.407 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations General Requirements § 250.407 What tests must I...

Hospital Nurses' Work Environment Characteristics and Patient Safety Outcomes: A Literature Review.

PubMed

Lee, Seung Eun; Scott, Linda D

2018-01-01

This integrative literature review assesses the relationship between hospital nurses' work environment characteristics and patient safety outcomes and recommends directions for future research based on examination of the literature. Using an electronic search of five databases, 18 studies published in English between 1999 and 2016 were identified for review. All but one study used a cross-sectional design, and only four used a conceptual/theoretical framework to guide the research. No definition of work environment was provided in most studies. Differing variables and instruments were used to measure patient outcomes, and findings regarding the effects of work environment on patient outcomes were inconsistent. To clarify the relationship between nurses' work environment characteristics and patient safety outcomes, researchers should consider using a longitudinal study design, using a theoretical foundation, and providing clear operational definitions of concepts. Moreover, given the inconsistent findings of previous studies, they should choose their measurement methodologies with care.

Thermoelectric power generator for variable thermal power source

DOEpatents

Bell, Lon E; Crane, Douglas Todd

2015-04-14

Traditional power generation systems using thermoelectric power generators are designed to operate most efficiently for a single operating condition. The present invention provides a power generation system in which the characteristics of the thermoelectrics, the flow of the thermal power, and the operational characteristics of the power generator are monitored and controlled such that higher operation efficiencies and/or higher output powers can be maintained with variably thermal power input. Such a system is particularly beneficial in variable thermal power source systems, such as recovering power from the waste heat generated in the exhaust of combustion engines.

Ideal MHD Stability and Characteristics of Edge Localized Modes on CFETR

NASA Astrophysics Data System (ADS)

Li, Zeyu; Chan, Vincent; Xu, Xueqiao; Wang, Xiaogang; Cfetr Physics Team

2017-10-01

Investigation on the equilibrium operation regime, its ideal magnetohydrodynamics (MHD) stability and edge localized modes (ELM) characteristics is performed for China Fusion Engineering Test Reactor (CFETR). The CFETR operation regime study starts with a baseline scenario derived from multi-code integrated modeling, with key parameters varied to build a systematic database. These parameters, under profile and pedestal constraints, provide the foundation for engineering design. The linear stabilities of low-n and intermediate-n peeling-ballooning modes for CFETR baseline scenario are analyzed. Multi-code benchmarking, including GATO, ELITE, BOUT + + and NIMROD, demonstrated good agreement in predicting instabilities. Nonlinear behavior of ELMs for the baseline scenario is simulated using BOUT + + . Instabilities are found both at the pedestal top and inside the pedestal region, which lead to a mix of grassy and type I ELMs. Pedestal structures extending inward beyond the pedestal top are also varied to study the influence on ELM characteristic. Preliminary results on the dependence of the Type-I ELM divertor heat load scaling on machine size and pedestal pressure will also be presented. Prepared by LLNL under Contract DE-AC52-07NA27344 and National Magnetic Confinement Fusion Research Program of China (Grant No. 2014GB110003 and 2014GB107004).

Influences of motorcycle rider and driver characteristics and road environment on red light running behavior at signalized intersections.

PubMed

Jensupakarn, Auearree; Kanitpong, Kunnawee

2018-04-01

In Thailand, red light running is considered as one of the most dangerous behaviors at intersection. Red light running (RLR) behavior is the failure to obey the traffic control signal. However, motorcycle riders and car drivers who are running through red lights could be influenced by human factors or road environment at intersection. RLR could be advertent or inadvertent behavior influenced by many factors. Little research study has been done to evaluate the contributing factors influencing the red-light violation behavior. This study aims to determine the factors influencing the red light running behavior including human characteristics, physical condition of intersection, traffic signal operation, and traffic condition. A total of 92 intersections were observed in Chiang Mai, Nakhon Ratchasima, and Chonburi, the major provinces in each region of Thailand. In addition, the socio-economic characteristics of red light runners were obtained from self-reported questionnaire survey. The Binary Logistic Regression and the Multiple Linear Regression models were used to determine the characteristics of red light runners and the factors influencing rates of red light running respectively. The results from this study can help to understand the characteristics of red light runners and factors affecting them to run red lights. For motorcycle riders and car drivers, age, gender, occupation, driving license, helmet/seatbelt use, and the probability to be penalized when running the red light significantly affect RLR behavior. In addition, the results indicated that vehicle travelling direction, time of day, existence of turning lane, number of lanes, lane width, intersection sight distance, type of traffic signal pole, type of traffic signal operation, length of yellow time interval, approaching speed, distance from intersection warning sign to stop line, and pavement roughness significantly affect RLR rates. Copyright © 2018 Elsevier Ltd. All rights reserved.

Characterization and Application of a Planar Radio - Inductively-Coupled Plasma Source for the Production of Barrier Coatings.

NASA Astrophysics Data System (ADS)

Mahoney, Leonard Joseph

A planar radio-frequency (rf) inductively-coupled plasma (ICP) source is used to produce fluorocarbon discharges (CF_4/Ar) to fluorinate the surface of high-density polyethylene (HDPE). Using this system, concurrent studies of discharge characteristics, permeation properties of treated polymers and polymer surface characteristics are conducted to advance the use of plasma-fluorinated polymer surfaces as a barrier layer for automotive applications. Langmuir probes are used to determine spatial distribution of charged-particle and space-potential characteristics in Ar and CF_4/Ar discharges and to show the influence of the spatial distribution of the heating regions and the reactor boundaries on the discharge uniformity. Langmuir probes are also used to identify rf anisotropic drift motion of electrons in the heating regions of the source and transient high-energy electron features in pulsed discharges. These latter features allow pulsed ICP sources to be operated at low time-averaged powers that are necessary to treat thermally sensitive polymers. Fourier Transform Infrared (FITR) spectroscopy is used to measure the dissociation of fluorocarbon gases and to explore differences between pulsed- and continuous -power operation. Dissociation levels of CF_4 (50-85%) using pulsed-power operation are as high as that for continuous operation, even though the net time -averaged power is far less with pulsed operation. The result suggests that pulsed fluorocarbon discharges possess high concentrations of chemically-active species needed for rapid surface fluorination. A gravimetric permeation cup method is used to measure the permeation rate of test fuels through HDPE membranes, and electron spectroscopy for chemical analysis (ESCA) studies are performed to determine the stoichiometry and thickness of the barrier layer. From these studies we find that a 50-70 A thick, polar, fluoro-hydrocarbon over layer reduces the permeation of isooctane/toluene/methanol mixtures by a factor of 4. To increase the permeation resistance for automotive applications, this result points towards the deposition of a 1000 A thick fluoro-hydrocarbon barrier coating with stoichiometry and bond structures similar to the CF_4/Ar treated HDPE.

Improvement of multi-level resistive switching characteristics in solution-processed AlO x -based non-volatile resistive memory using microwave irradiation

NASA Astrophysics Data System (ADS)

Kim, Seung-Tae; Cho, Won-Ju

2018-01-01

We fabricated a resistive random access memory (ReRAM) device on a Ti/AlO x /Pt structure with solution-processed AlO x switching layer using microwave irradiation (MWI), and demonstrated multi-level cell (MLC) operation. To investigate the effect of MWI power on the MLC characteristics, post-deposition annealing was performed at 600-3000 W after AlO x switching layer deposition, and the MLC operation was compared with as-deposited (as-dep) and conventional thermally annealing (CTA) treated devices. All solution-processed AlO x -based ReRAM devices exhibited bipolar resistive switching (BRS) behavior. We found that these devices have four-resistance states (2 bits) of MLC operation according to the modulation of the high-resistance state (HRSs) through reset voltage control. Particularly, compared to the as-dep and CTA ReRAM devices, the MWI-treated ReRAM devices showed a significant increase in the memory window and stable endurance for multi-level operation. Moreover, as the MWI power increased, excellent MLC characteristics were exhibited because the resistance ratio between each resistance state was increased. In addition, it exhibited reliable retention characteristics without deterioration at 25 °C and 85 °C for 10 000 s. Finally, the relationship between the chemical characteristics of the solution-processed AlO x switching layer and BRS-based multi-level operation according to the annealing method and MWI power was investigated using x-ray photoelectron spectroscopy.

IR radiation characteristics and operating range research for a quad-rotor unmanned aircraft vehicle.

PubMed

Gong, Mali; Guo, Rui; He, Sifeng; Wang, Wei

2016-11-01

The security threats caused by multi-rotor unmanned aircraft vehicles (UAVs) are serious, especially in public places. To detect and control multi-rotor UAVs, knowledge of IR characteristics is necessary. The IR characteristics of a typical commercial quad-rotor UAV are investigated in this paper through thermal imaging with an IR camera. Combining the 3D geometry and IR images of the UAV, a 3D IR characteristics model is established so that the radiant power from different views can be obtained. An estimation of operating range to detect the UAV is calculated theoretically using signal-to-noise ratio as the criterion. Field experiments are implemented with an uncooled IR camera in an environment temperature of 12°C and a uniform background. For the front view, the operating range is about 150 m, which is close to the simulation result of 170 m.

Bedside Treatment of Chronic Subdural Hematoma: Using Radiographic Characteristics to Revisit the Twist Drill.

PubMed

Garber, Sarah; McCaffrey, Jamie; Quigley, Edward P; MacDonald, Joel D

2016-05-01

Conventional treatment strategies for the management of symptomatic chronic subdural hematoma (cSDH) in the elderly include observation, operative burr holes or craniotomy, and bedside twist drill drainage. The decision on which technique to use should be determined by weighing the comorbidities and symptoms of the patient with the potential risks and benefits. The goal of this study was to identify radiographic characteristics on computed tomography scan that might be used to guide surgical decision making in terms of operative versus bedside removal of cSDH. We retrospectively reviewed clinical and radiographic features in patients who underwent bedside twist drill evacuation of a cSDH and those for a cohort of patients who underwent operative intervention via burr holes. We did not identify any clinical features or preoperative imaging characteristics to suggest an advantage of one procedure over the other. Additionally, complete radiographic resolution of cSDH on postoperative imaging is not required to relieve patient symptoms. Although bedside twist drill evacuation may avoid operating room costs and anesthetic complications in an elderly patient population and allow earlier resumption of anticoagulation treatment if necessary, there is also a risk of morbidity if uncontrolled bleeding is encountered or the patient is unable to tolerate the bedside procedure. However, bedside twist drill craniostomy is a reasonable and effective option for the treatment of subacute/chronic SDH in patients who may not be optimal surgical candidates. Georg Thieme Verlag KG Stuttgart · New York.

When high-volume PCI operators in high-volume hospitals move to lower volume hospitals-Do they still maintain high volume and quality of outcomes?

PubMed

Lu, Tsung-Hsueh; Li, Sheng-Tun; Liang, Fu-Wen; Lee, Jo-Chi; Yin, Wei-Hsian

2017-10-31

The aim of this quasi-experimental study was to examine whether high-volume percutaneous coronary intervention (PCI) operators still maintain high volume and quality of outcomes when they moved to lower volume hospitals. Systematic reviews have indicated that high-volume PCI operators and hospitals have higher quality outcomes. However, little is known on whether high PCI volume and high quality outcomes are mainly due to operator characteristics (i.e., skill and experience) and is portable across organizations or whether it is due to hospital characteristics (i.e., equipment, team, and management system) and is less portable. We used Taiwan National Health Insurance claims data 2000-2012 to identify 98 high-volume PCI operators, 10 of whom moved from one hospital to another during the study period. We compared the PCI volume, risk-adjusted mortality ratio, and major adverse cardiovascular event (MACE) ratio before and after moving. Of the 10 high-volume operators who moved, 6 moved from high- to moderate- or low-volume hospitals, with median annual PCI volumes (interquartile range) of 130 (117-165) in prior hospitals and 54 (46-84) in subsequent hospitals (the hospital the operator moved to), and the remaining 4 moved from high to high-volume hospitals, with median annual PCI volumes (interquartile range) of 151 (133-162) in prior hospitals and 193 (178-239) in subsequent hospitals. No significant differences were observed in the risk-adjusted mortality ratios and MACE ratios between high-volume operators and matched controls before and after moving. High-volume operators cannot maintain high volume when they moved from high to moderate or low-volume hospitals; however, the quality of care is maintained. High PCI volume and high-quality outcomes are less portable and more hospital bound. © 2017 Wiley Periodicals, Inc.

NASA Reactor Facility Hazards Summary. Volume 1

NASA Technical Reports Server (NTRS)

1959-01-01

The Lewis Research Center of the National Aeronautics and Space Administration proposes to build a nuclear research reactor which will be located in the Plum Brook Ordnance Works near Sandusky, Ohio. The purpose of this report is to inform the Advisory Committee on Reactor Safeguards of the U. S. Atomic Energy Commission in regard to the design Lq of the reactor facility, the characteristics of the site, and the hazards of operation at this location. The purpose of this research reactor is to make pumped loop studies of aircraft reactor fuel elements and other reactor components, radiation effects studies on aircraft reactor materials and equipment, shielding studies, and nuclear and solid state physics experiments. The reactor is light water cooled and moderated of the MTR-type with a primary beryllium reflector and a secondary water reflector. The core initially will be a 3 by 9 array of MTR-type fuel elements and is designed for operation up to a power of 60 megawatts. The reactor facility is described in general terms. This is followed by a discussion of the nuclear characteristics and performance of the reactor. Then details of the reactor control system are discussed. A summary of the site characteristics is then presented followed by a discussion of the larger type of experiments which may eventually be operated in this facility. The considerations for normal operation are concluded with a proposed method of handling fuel elements and radioactive wastes. The potential hazards involved with failures or malfunctions of this facility are considered in some detail. These are examined first from the standpoint of preventing them or minimizing their effects and second from the standpoint of what effect they might have on the reactor facility staff and the surrounding population. The most essential feature of the design for location at the proposed site is containment of the maximum credible accident.

Timing of Occurrence Is the Most Important Characteristic of Spot Sign.

PubMed

Wang, Binli; Yan, Shenqiang; Xu, Mengjun; Zhang, Sheng; Liu, Keqin; Hu, Haitao; Selim, Magdy; Lou, Min

2016-05-01

Most previous studies have used single-phase computed tomographic angiography to detect the spot sign, a marker for hematoma expansion (HE) in spontaneous intracerebral hemorrhage. We investigated whether defining the spot sign based on timing on perfusion computed tomography (CTP) would improve its specificity for predicting HE. We prospectively enrolled supratentorial spontaneous intracerebral hemorrhage patients who underwent CTP within 6 hours of onset. Logistic regression was performed to assess the risk factors for HE and poor outcome. Predictive performance of individual CTP spot sign characteristics were examined with receiver operating characteristic analysis. Sixty-two men and 21 women with spontaneous intracerebral hemorrhage were included in this analysis. Spot sign was detected in 46% (38/83) of patients. Receiver operating characteristic analysis indicated that the timing of spot sign occurrence on CTP had the greatest area under receiver operating characteristic curve for HE (0.794; 95% confidence interval, 0.630-0.958; P=0.007); the cutoff time was 23.13 seconds. On multivariable analysis, the presence of early-occurring spot sign (ie, spot sign before 23.13 seconds) was an independent predictor not only of HE (odds ratio=28.835; 95% confidence interval, 6.960-119.458; P<0.001), but also of mortality at 3 months (odds ratio =22.377; 95% confidence interval, 1.773-282.334; P=0.016). Moreover, the predictive performance showed that the redefined early-occurring spot sign maintained a higher specificity for HE compared with spot sign (91% versus 74%). Redefining the spot sign based on timing of contrast leakage on CTP to determine early-occurring spot sign improves the specificity for predicting HE and 3-month mortality. The use of early-occurring spot sign could improve the selection of ICH patients for potential hemostatic therapy. © 2016 American Heart Association, Inc.

Instrument for evaluation of sedentary lifestyle in patients with high blood pressure.

PubMed

Lopes, Marcos Venícios de Oliveira; da Silva, Viviane Martins; de Araujo, Thelma Leite; Guedes, Nirla Gomes; Martins, Larissa Castelo Guedes; Teixeira, Iane Ximenes

2015-01-01

this article describes the diagnostic accuracy of the International Physical Activity Questionnaire to identify the nursing diagnosis of sedentary lifestyle. a diagnostic accuracy study was developed with 240 individuals with established high blood pressure. The analysis of diagnostic accuracy was based on measures of sensitivity, specificity, predictive values, likelihood ratios, efficiency, diagnostic odds ratio, Youden index, and area under the receiver-operating characteristic curve. statistical differences between genders were observed for activities of moderate intensity and for total physical activity. Age was negatively correlated with activities of moderate intensity and total physical activity. the analysis of area under the receiver-operating characteristic curve for moderate intensity activities, walking, and total physical activity showed that the International Physical Activity Questionnaire present moderate capacity to correctly classify individuals with and without sedentary lifestyle.

Channel width dependence of electrical characteristics of a-Si:H TFTs under bending stresses

NASA Astrophysics Data System (ADS)

Oh, Hyungon; Cho, Kyoungah; Kim, Sangsig

2017-04-01

In this study, we investigate the electrical characteristics of bendable a-Si:H thin-film transistors (TFTs) with various channel widths as a function of bending stress. Compared with a narrower channel TFT, a wider channel TFT exhibits a stable performance even at a bending strain of 1.3%. Our stress and strain distribution analysis reveals an inverse relationship between the channel width and the channel stress. As the channel width widens from 8 to 50 μm, the stress experienced by the middle channel region decreases from 545 to 277 MPa. Moreover, a 50 μm-channel-width TFT operates stably even after a 15 000 bending cycle while the 8 μm-channel-width TFT fails to operate after a 2000 bending cycle.

Optically-powered Voltage-supply-device for Effective Utilization of Optical Energy in the Fiber-To-The-Home Network

NASA Astrophysics Data System (ADS)

Fukano, Hideki; Shinagawa, Takeshi; Tsuruta, Kenji

An optically powered device with using InGaAs-Photodiode has been developed. This study aims to harvest light energy (2.8∼500μW) from the FTTH (Fiber To The Home) network and to utilize it for operating remote sensors without external energy sources. First, we designed and evaluated the characteristics of the booster circuit and confirmed that it could boost an input voltage of 0.3 V to 3.0 V. Next, we also evaluated the characteristics of InGaAs photodiode and confirmed that it can output a voltage over 0.3 V at 10-μW input light. We demonstrate that a ready-made sensor can be operated with an input optical power as low as 10 μW.

An assessment of high-speed rail safety issues and research needs

DOT National Transportation Integrated Search

1990-12-01

The objectives of the study were to provide the Federal Railroad Administration Office of Research and Development with the following information: A general description and operating characteristics of high-speed rail systems likely to be installed i...

Numerical analysis on the cutting and finishing efficiency of MRAFF process

NASA Astrophysics Data System (ADS)

Lih, F. L.

2016-03-01

The aim of the present research is to conduct a numerical study of the characteristic of a two-phase magnetorheological fluid with different operation conditions by the finite volume method called SIMPLE with an add-on MHD code.

Executive edition : New Jersey I-80 and I-287 HOV lane case study

DOT National Transportation Integrated Search

2000-05-01

The report provides the American people with a national perspective on the physical and operating characteristics of the highway, bridge, and transit portions of the nation's intermodal transportation system. It offers a comprehensive, factual backgr...

Characteristics of pulse gold vapor laser outlined

NASA Astrophysics Data System (ADS)

1981-09-01

Several dozen laser oscillating spectra lines were found within the very broad spectral wavelengths from infrared to ultraviolet. Laser studies of gold vapor were carried out and a pulsed laser of gold atoms of an operating wavelength of 6278 angstroms was obtained.

Summarized Data of Test Space Heating, Ventilation and Air Conditioning Inspections from the Building Assessment Survey and Evaluation Study

EPA Pesticide Factsheets

Information on the characteristics of the heating, ventilation, and air conditioning (HVAC) system(s) in the entire BASE building including types of ventilation, equipment configurations, and operation and maintenance issues

Statistical and Spectral Analysis of Wind Characteristics Relevant to Wind Energy Assessment Using Tower Measurements in Complex Terrain

DOE PAGES

Belu, Radian; Koracin, Darko

2013-01-01

The main objective of the study was to investigate spatial and temporal characteristics of the wind speed and direction in complex terrain that are relevant to wind energy assessment and development, as well as to wind energy system operation, management, and grid integration. Wind data from five tall meteorological towers located in Western Nevada, USA, operated from August 2003 to March 2008, used in the analysis. The multiannual average wind speeds did not show significant increased trend with increasing elevation, while the turbulence intensity slowly decreased with an increase were the average wind speed. The wind speed and direction weremore » modeled using the Weibull and the von Mises distribution functions. The correlations show a strong coherence between the wind speed and direction with slowly decreasing amplitude of the multiday periodicity with increasing lag periods. The spectral analysis shows significant annual periodicity with similar characteristics at all locations. The relatively high correlations between the towers and small range of the computed turbulence intensity indicate that wind variability is dominated by the regional synoptic processes. Knowledge and information about daily, seasonal, and annual wind periodicities are very important for wind energy resource assessment, wind power plant operation, management, and grid integration.« less

Space station operations task force summary report

NASA Technical Reports Server (NTRS)

1987-01-01

A companion to the Space Stations Operation Task Force Panels' Reports, this document summarizes all space station program goals, operations, and the characteristics of the expected user community. Strategies for operation and recommendations for implementation are included.

Application Performance Analysis and Efficient Execution on Systems with multi-core CPUs, GPUs and MICs: A Case Study with Microscopy Image Analysis

PubMed Central

Teodoro, George; Kurc, Tahsin; Andrade, Guilherme; Kong, Jun; Ferreira, Renato; Saltz, Joel

2015-01-01

We carry out a comparative performance study of multi-core CPUs, GPUs and Intel Xeon Phi (Many Integrated Core-MIC) with a microscopy image analysis application. We experimentally evaluate the performance of computing devices on core operations of the application. We correlate the observed performance with the characteristics of computing devices and data access patterns, computation complexities, and parallelization forms of the operations. The results show a significant variability in the performance of operations with respect to the device used. The performances of operations with regular data access are comparable or sometimes better on a MIC than that on a GPU. GPUs are more efficient than MICs for operations that access data irregularly, because of the lower bandwidth of the MIC for random data accesses. We propose new performance-aware scheduling strategies that consider variabilities in operation speedups. Our scheduling strategies significantly improve application performance compared to classic strategies in hybrid configurations. PMID:28239253

Investigating the Nature of and Methods for Managing Metroplex Operations

NASA Technical Reports Server (NTRS)

Atkins, Stephen; Capozzi, Brian; Hinkey, Jim; Idris, Husni; Kaiser, Kent

2011-01-01

A combination of traffic demand growth, Next Generation Air Transportation System (NextGen) technologies and operational concepts, and increased utilization of regional airports is expected to increase the occurrence and severity of coupling between operations at proximate airports. These metroplex phenomena constrain the efficiency and/or capacity of airport operations and, in NextGen, have the potential to reduce safety and prevent environmental benefits. Without understanding the nature of metroplexes and developing solutions that provide efficient coordination of operations between closely-spaced airports, the use of NextGen technologies and distribution of demand to regional airports may provide little increase in the overall metroplex capacity. However, the characteristics and control of metroplex operations have not received significant study. This project advanced the state of knowledge about metroplexes by completing three objectives: 1. developed a foundational understand of the nature of metroplexes; 2. provided a framework for discussing metroplexes; 3. suggested and studied an approach for optimally managing metroplexes that is consistent with other NextGen concepts

National Hydropower Plant Dataset, Version 2 (FY18Q3)

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

Samu, Nicole; Kao, Shih-Chieh; O'Connor, Patrick

The National Hydropower Plant Dataset, Version 2 (FY18Q3) is a geospatially comprehensive point-level dataset containing locations and key characteristics of U.S. hydropower plants that are currently either in the hydropower development pipeline (pre-operational), operational, withdrawn, or retired. These data are provided in GIS and tabular formats with corresponding metadata for each. In addition, we include access to download 2 versions of the National Hydropower Map, which was produced with these data (i.e. Map 1 displays the geospatial distribution and characteristics of all operational hydropower plants; Map 2 displays the geospatial distribution and characteristics of operational hydropower plants with pumped storagemore » and mixed capabilities only). This dataset is a subset of ORNL's Existing Hydropower Assets data series, updated quarterly as part of ORNL's National Hydropower Asset Assessment Program.« less

Novel bidirectional DC-DC converters based on the three-state switching cell

NASA Astrophysics Data System (ADS)

da Silva Júnior, José Carlos; Robles Balestero, Juan Paulo; Lessa Tofoli, Fernando

2016-05-01

It is well known that there is an increasing demand for bidirectional DC-DC converters for applications that range from renewable energy sources to electric vehicles. Within this context, this work proposes novel DC-DC converter topologies that use the three-state switching cell (3SSC), whose well-known advantages over conventional existing structures are ability to operate at high current levels, while current sharing is maintained by a high frequency transformer; reduction of cost and dimensions of magnetics; improved distribution of losses, with consequent increase of global efficiency and reduction of cost associated to the need of semiconductors with lower current ratings. Three distinct topologies can be derived from the 3SSC: one DC-DC converter with reversible current characteristic able to operate in the first and second quadrants; one DC-DC converter with reversible voltage characteristic able to operate in the first and third quadrants and one DC-DC converter with reversible current and voltage characteristics able to operate in four quadrants. Only the topology with bidirectional current characteristic is analysed in detail in terms of the operating stages in both nonoverlapping and overlapping modes, while the design procedure of the power stage elements is obtained. In order to validate the theoretical assumptions, an experimental prototype is also implemented, so that relevant issues can be properly discussed.

NTREES Testing and Operations Status

NASA Technical Reports Server (NTRS)

Emrich, Bill

2007-01-01

Nuclear Thermal Rockets or NTR's have been suggested as a propulsion system option for vehicles traveling to the moon or Mars. These engines are capable of providing high thrust at specific impulses at least twice that of today's best chemical engines. The performance constraints on these engines are mainly the result of temperature limitations on the fuel coupled with a limited ability to withstand chemical attack by the hot hydrogen propellant. To operate at maximum efficiency, fuel forms are desired which can withstand the extremely hot, hostile environment characteristic of NTR operation for at least several hours. The simulation of such an environment would require an experimental device which could simultaneously approximate the power, flow, and temperature conditions which a nuclear fuel element (or partial element) would encounter during NTR operation. Such a simulation would allow detailed studies of the fuel behavior and hydrogen flow characteristics under reactor like conditions to be performed. Currently, the construction of such a simulator has been completed at the Marshall Space Flight Center, and will be used in the future to evaluate a wide variety of fuel element designs and the materials of which they are fabricated. This present work addresses the operational status of the Nuclear Thermal Rocket Element Environmental Simulator or NTREES and some of the design considerations which were considered prior to and during its construction.

Study of quiet turbofan STOL aircraft for short-haul transportation. Volume 1: Summary

NASA Technical Reports Server (NTRS)

1974-01-01

Conceptual designs of Quiet Turbofan STOL Short-Haul Transport Aircraft for the mid-1980 time period are developed and analyzed to determine their technical, operational, and economic feasibility. A matrix of aircraft using various high-lift systems and design parameters are considered. Variations in aircraft characteristics, airport geometry and location, and operational techniques are analyzed systematically to determine their effects on the market, operating economics, and community acceptance. The total systems approach is considered to be critically important in analyzing the potential of STOL aircraft to reduce noise pollution and alleviate the increasing air corridor and airport congestion.

Computer users' postures and associations with workstation characteristics.

PubMed

Gerr, F; Marcus, M; Ortiz, D; White, B; Jones, W; Cohen, S; Gentry, E; Edwards, A; Bauer, E

2000-01-01

This investigation tested the hypotheses that (1) physical workstation dimensions are important determinants of operator posture, (2) specific workstation characteristics systematically affect worker posture, and (3) computer operators assume "neutral" upper limb postures while keying. Operator head, neck, and upper extremity posture and selected workstation dimensions and characteristics were measured among 379 computer users. Operator postures were measured with manual goniometers, workstation characteristics were evaluated by observation, and workstation dimensions by direct measurement. Considerably greater variability in all postures was observed than was expected from application of basic geometric principles to measured workstation dimensions. Few strong correlations were observed between worker posture and workstation physical dimensions; findings suggest that preference is given to keyboard placement with respect to the eyes (r = 0.60 for association between keyboard height and seated elbow height) compared with monitor placement with respect to the eyes (r = 0.18 for association between monitor height and seated eye height). Wrist extension was weakly correlated with keyboard height (r = -0.24) and virtually not at all with keyboard thickness (r = 0.07). Use of a wrist rest was associated with decreased wrist flexion (21.9 versus 25.1 degrees, p < 0.01). Participants who had easily adjustable chairs had essentially the same neck and upper limb postures as did those with nonadjustable chairs. Sixty-one percent of computer operators were observed in nonneutral shoulder postures and 41% in nonneutral wrist postures. Findings suggest that (1) workstation dimensions are not strong determinants of at least several neck and upper extremity postures among computer operators, (2) only some workstation characteristics affect posture, and (3) contrary to common recommendations, a large proportion of computer users do not work in so-called neutral postures.

20 kHz main inverter unit. [for space station power supplies

NASA Technical Reports Server (NTRS)

Hussey, S.

1989-01-01

A proof-of-concept main inverter unit has demonstrated the operation of a pulse-width-modulated parallel resonant power stage topology as a 20-kHz ac power source driver, showing simple output regulation, parallel operation, power sharing and short-circuit operation. The use of a two-stage dc input filter controls the electromagnetic compatibility (EMC) characteristics of the dc power bus, and the use of an ac harmonic trap controls the EMC characteristics of the 20-kHz ac power bus.

Regenerative fuel cell energy storage system for a low earth orbit space station

NASA Technical Reports Server (NTRS)

Martin, R. E.; Garow, J.; Michaels, K. B.

1988-01-01

A study was conducted to define characteristics of a Regenerative Fuel Cell System (RFCS) for low earth orbit Space Station missions. The RFCS's were defined and characterized based on both an alkaline electrolyte fuel cell integrated with an alkaline electrolyte water electrolyzer and an alkaline electrolyte fuel cell integrated with an acid solid polymer electrolyte (SPE) water electrolyzer. The study defined the operating characteristics of the systems including system weight, volume, and efficiency. A maintenance philosophy was defined and the implications of system reliability requirements and modularization were determined. Finally, an Engineering Model System was defined and a program to develop and demonstrate the EMS and pacing technology items that should be developed in parallel with the EMS were identified. The specific weight of an optimized RFCS operating at 140 F was defined as a function of system efficiency for a range of module sizes. An EMS operating at a nominal temperature of 180 F and capable of delivery of 10 kW at an overall efficiency of 55.4 percent is described. A program to develop the EMS is described including a technology development effort for pacing technology items.

Use of designated boat operators and designated drivers among college students.

PubMed

Cheong, JeeWon; Hall, Nicole M; MacKinnon, David P

2006-07-01

Prior research has shown that designated drivers (DD) are widely used as a preventive measure for driving under the influence. Despite the prevalence of alcohol involvement in boating accidents, much less is known about the use of a designated boat operator (DBO). The current study investigated the prevalence of DBO use in recreational boating and compared the characteristics of DD users and DBO users. Several survey questionnaires were distributed to a group of undergraduate students at a large southwestern university for the purpose of investigating demographic characteristics, alcohol-use pattern, and other alcohol-related problem behaviors, such as driving and boating under the influence. Approximately 45% of the boaters reported they had drunk alcohol while boating, and approximately 70% had used a DBO in the most recent boating event. The DBO users were found to be similar to the DD users in terms of drinking pattern, age of drinking onset, and driving behaviors. High rates of alcohol use in recreational boating suggest the need for prevention strategies. Furthermore, future studies are needed to investigate the selection process of the DBOs and the differences between passengers and boat operators, which could shed light on strategies to prevent alcohol- involved boating injuries.

Protective clothing for pesticide operators: part II--data analysis of fabric characteristics.

PubMed

Shaw, Anugrah; Schiffelbein, Paul

2016-01-01

Development of objective measurements is an important requirement for establishing performance-based standards for protective clothing used while handling pesticide. This study, the second in a two-part series, reports on the work completed to evaluate the performance of approximately 100 fabrics that are either used or have the potential to be used for garments worn by operators while applying pesticides. Part I, published separately, provides an overview of these issues and describes research undertaken to select a test chemical for use in subsequent studies. The goals of this study were first to develop a comprehensive approach to evaluate the performance of garments currently being used by pesticide operators, and second, to use the laboratory and field data in the development of performance specifications.

Review of thermo-physical properties, wetting and heat transfer characteristics of nanofluids and their applicability in industrial quench heat treatment

PubMed Central

2011-01-01

The success of quenching process during industrial heat treatment mainly depends on the heat transfer characteristics of the quenching medium. In the case of quenching, the scope for redesigning the system or operational parameters for enhancing the heat transfer is very much limited and the emphasis should be on designing quench media with enhanced heat transfer characteristics. Recent studies on nanofluids have shown that these fluids offer improved wetting and heat transfer characteristics. Further water-based nanofluids are environment friendly as compared to mineral oil quench media. These potential advantages have led to the development of nanofluid-based quench media for heat treatment practices. In this article, thermo-physical properties, wetting and boiling heat transfer characteristics of nanofluids are reviewed and discussed. The unique thermal and heat transfer characteristics of nanofluids would be extremely useful for exploiting them as quench media for industrial heat treatment. PMID:21711877

Review of thermo-physical properties, wetting and heat transfer characteristics of nanofluids and their applicability in industrial quench heat treatment.

PubMed

Ramesh, Gopalan; Prabhu, Narayan Kotekar

2011-04-14

The success of quenching process during industrial heat treatment mainly depends on the heat transfer characteristics of the quenching medium. In the case of quenching, the scope for redesigning the system or operational parameters for enhancing the heat transfer is very much limited and the emphasis should be on designing quench media with enhanced heat transfer characteristics. Recent studies on nanofluids have shown that these fluids offer improved wetting and heat transfer characteristics. Further water-based nanofluids are environment friendly as compared to mineral oil quench media. These potential advantages have led to the development of nanofluid-based quench media for heat treatment practices. In this article, thermo-physical properties, wetting and boiling heat transfer characteristics of nanofluids are reviewed and discussed. The unique thermal and heat transfer characteristics of nanofluids would be extremely useful for exploiting them as quench media for industrial heat treatment.

Activity in the Lifestyles of Adolescent Girls.

ERIC Educational Resources Information Center

Fry, Joan

This study was conducted to determine the significance of physical activity in the lifestyles of a selected group of female adolescents. Two groups of girls in their mid-teens, identified through a pilot study, were operationally defined as activity seekers (N=14) and non-activity seekers (N=14). In order to determine the characteristics of both…

The "Village" Model: A Consumer-Driven Approach for Aging in Place

ERIC Educational Resources Information Center

Scharlach, Andrew; Graham, Carrie; Lehning, Amanda

2012-01-01

Purpose of the Study: This study examines the characteristics of the "Village" model, an innovative consumer-driven approach that aims to promote aging in place through a combination of member supports, service referrals, and consumer engagement. Design and Methods: Thirty of 42 fully operational Villages completed 2 surveys. One survey examined…

Artificial neural network approach to predict surgical site infection after free-flap reconstruction in patients receiving surgery for head and neck cancer

PubMed Central

Kuo, Pao-Jen; Wu, Shao-Chun; Chien, Peng-Chen; Chang, Shu-Shya; Rau, Cheng-Shyuan; Tai, Hsueh-Ling; Peng, Shu-Hui; Lin, Yi-Chun; Chen, Yi-Chun; Hsieh, Hsiao-Yun; Hsieh, Ching-Hua

2018-01-01

Background The aim of this study was to develop an effective surgical site infection (SSI) prediction model in patients receiving free-flap reconstruction after surgery for head and neck cancer using artificial neural network (ANN), and to compare its predictive power with that of conventional logistic regression (LR). Materials and methods There were 1,836 patients with 1,854 free-flap reconstructions and 438 postoperative SSIs in the dataset for analysis. They were randomly assigned tin ratio of 7:3 into a training set and a test set. Based on comprehensive characteristics of patients and diseases in the absence or presence of operative data, prediction of SSI was performed at two time points (pre-operatively and post-operatively) with a feed-forward ANN and the LR models. In addition to the calculated accuracy, sensitivity, and specificity, the predictive performance of ANN and LR were assessed based on area under the curve (AUC) measures of receiver operator characteristic curves and Brier score. Results ANN had a significantly higher AUC (0.892) of post-operative prediction and AUC (0.808) of pre-operative prediction than LR (both P<0.0001). In addition, there was significant higher AUC of post-operative prediction than pre-operative prediction by ANN (p<0.0001). With the highest AUC and the lowest Brier score (0.090), the post-operative prediction by ANN had the highest overall predictive performance. Conclusion The post-operative prediction by ANN had the highest overall performance in predicting SSI after free-flap reconstruction in patients receiving surgery for head and neck cancer. PMID:29568393

Booster Main Engine Selection Criteria for the Liquid Fly-Back Booster

NASA Technical Reports Server (NTRS)

Ryan, Richard M.; Rothschild, William J.; Christensen, David L.

1998-01-01

The Liquid Fly-Back Booster (LFBB) Program seeks to enhance the Space Shuttle system safety performance and economy of operations through the use of an advanced, liquid propellant Booster Main Engine (BME). There are several viable BME candidates that could be suitable for this application. The objective of this study was to identify the key criteria to be applied in selecting among these BME candidates. This study involved an assessment of influences on the overall LFBB utility due to variations in the candidate rocket engines' characteristics. This includes BME impacts on vehicle system weight, perfortnance,design approaches, abort modes, margins of safety, engine-out operations, and maintenance and support concepts. Systems engineering analyses and trade studies were performed to identify the LFBB system level sensitivities to a wide variety of BME related parameters. This presentation summarizes these trade studies and the resulting findings of the LFBB design teams regarding the BME characteristics that most significantly affect the LFBB system. The resulting BME choice should offer the best combination of reliability, performance, reusability, robustness, cost, and risk for the LFBB program.

Booster Main Engine Selection Criteria for the Liquid Fly-Back Booster

NASA Technical Reports Server (NTRS)

Ryan, Richard M.; Rothschild, William J.; Christensen, David L.

1998-01-01

The Liquid Fly-Back Booster (LFBB) Program seeks to enhance the Space Shuttle system safety, performance and economy of operations through the use of an advanced, liquid propellant Booster Main Engine (BME). There are several viable BME candidates that could be suitable for this application. The objective of this study was to identify the key Criteria to be applied in selecting among these BME candidates. This study involved an assessment of influences on the overall LFBB utility due to variations in the candidate rocket-engines characteristics. This includes BME impacts on vehicle system weight, performance, design approaches, abort modes, margins of safety, engine-out operations, and maintenance and support concepts. Systems engineering analyses and trade studies were performed to identify the LFBB system level sensitivities to a wide variety of BME related parameters. This presentation summarizes these trade studies and the resulting findings of the LFBB design teams regarding the BME characteristics that most significantly affect the LFBB system. The resulting BME choice should offer the best combination of reliability, performance, reusability, robustness, cost, and risk for the LFBB program.

Sensitivity study of Space Station Freedom operations cost and selected user resources

NASA Technical Reports Server (NTRS)

Accola, Anne; Fincannon, H. J.; Williams, Gregory J.; Meier, R. Timothy

1990-01-01

The results of sensitivity studies performed to estimate probable ranges for four key Space Station parameters using the Space Station Freedom's Model for Estimating Space Station Operations Cost (MESSOC) are discussed. The variables examined are grouped into five main categories: logistics, crew, design, space transportation system, and training. The modification of these variables implies programmatic decisions in areas such as orbital replacement unit (ORU) design, investment in repair capabilities, and crew operations policies. The model utilizes a wide range of algorithms and an extensive trial logistics data base to represent Space Station operations. The trial logistics data base consists largely of a collection of the ORUs that comprise the mature station, and their characteristics based on current engineering understanding of the Space Station. A nondimensional approach is used to examine the relative importance of variables on parameters.

Characteristics of Operational Space Weather Forecasting: Observations and Models

NASA Astrophysics Data System (ADS)

Berger, Thomas; Viereck, Rodney; Singer, Howard; Onsager, Terry; Biesecker, Doug; Rutledge, Robert; Hill, Steven; Akmaev, Rashid; Milward, George; Fuller-Rowell, Tim

2015-04-01

In contrast to research observations, models and ground support systems, operational systems are characterized by real-time data streams and run schedules, with redundant backup systems for most elements of the system. We review the characteristics of operational space weather forecasting, concentrating on the key aspects of ground- and space-based observations that feed models of the coupled Sun-Earth system at the NOAA/Space Weather Prediction Center (SWPC). Building on the infrastructure of the National Weather Service, SWPC is working toward a fully operational system based on the GOES weather satellite system (constant real-time operation with back-up satellites), the newly launched DSCOVR satellite at L1 (constant real-time data network with AFSCN backup), and operational models of the heliosphere, magnetosphere, and ionosphere/thermosphere/mesophere systems run on the Weather and Climate Operational Super-computing System (WCOSS), one of the worlds largest and fastest operational computer systems that will be upgraded to a dual 2.5 Pflop system in 2016. We review plans for further operational space weather observing platforms being developed in the context of the Space Weather Operations Research and Mitigation (SWORM) task force in the Office of Science and Technology Policy (OSTP) at the White House. We also review the current operational model developments at SWPC, concentrating on the differences between the research codes and the modified real-time versions that must run with zero fault tolerance on the WCOSS systems. Understanding the characteristics and needs of the operational forecasting community is key to producing research into the coupled Sun-Earth system with maximal societal benefit.

Analysis of high injection pressure and ambient temperature on biodiesel spray characteristics using computational fluid dynamics

NASA Astrophysics Data System (ADS)

Hashim, Akasha; Khalid, Amir; Jaat, Norrizam; Sapit, Azwan; Razali, Azahari; Nizam, Akmal

2017-09-01

Efficiency of combustion engines are highly affected by the formation of air-fuel mixture prior to ignition and combustion process. This research investigate the mixture formation and spray characteristics of biodiesel blends under variant in high ambient and injection conditions using Computational Fluid Dynamics (CFD). The spray characteristics such as spray penetration length, spray angle and fluid flow were observe under various operating conditions. Results show that increase in injection pressure increases the spray penetration length for both biodiesel and diesel. Results also indicate that higher spray angle of biodiesel can be seen as the injection pressure increases. This study concludes that spray characteristics of biodiesel blend is greatly affected by the injection and ambient conditions.

PC-402 Pioneer Venus orbiter spacecraft mission operational characteristics document

NASA Technical Reports Server (NTRS)

Barker, F. C.; Butterworth, L. W.; Daniel, R. E.; Drean, R. J.; Filetti, K. A.; Fisher, J. N.; Nowak, L. A.; Porzucki, J.; Salvatore, J. O.; Tadler, G. A.

1978-01-01

The operational characteristics of the Orbiter spacecraft and its subsystems are described. In extensive detail. Description of the nominal phases, system interfaces, and the capabilities and limitations of system level performance are included along with functional and operational descriptions at the subsystem and unit level the subtleties of nominal operation as well as detailed capabilities and limitations beyond nominal performance are discussed. A command and telemetry logic flow diagram for each subsystem is included. Each diagram encountered along each command signal path into, and each telemetry signal path out of the subsystem. Normal operating modes that correspond to the performance of specific functions at the time of specific events in the mission are also discussed. Principal backup means of performing the normal Orbiter operating modes are included.

Basic Characteristics and Particularities of Nongovernment Education in China

ERIC Educational Resources Information Center

Daguang, Wu

2009-01-01

Running schools on the basis of nonpublic investment has been a basic characteristic of nongovernment or non-public-sector operated education in China since the advent of reform and opening up. This is not merely an unavoidable choice for school operators who have no other alternative; it is an inevitable option at a given period in the…

Receiver Operating Characteristic Curve Analysis of Wechsler Memory Scale-Revised Scores in Epilepsy Surgery Candidates.

ERIC Educational Resources Information Center

Barr, William B.

1997-01-01

Wechsler Memory Scale-Revised (WMS-R) scores were analyzed for 82 epilepsy surgery candidates and used in combination with receiver operating characteristic curves to classify patients with left (LTL) and right (RTL) temporal lobe seizure onset. Results indicate that WMS-R scores used alone or in combination provide relatively poor discrimination…

Nickel-cadium batteries for Apollo telescope mount

NASA Technical Reports Server (NTRS)

Kirsch, W. W.; Shikoh, A. E.

1974-01-01

The operational testing and evaluation program is presented which was conducted on 20-ampere-hour nickel-cadmium (Ni-Cd) batteries for use on the Apollo telescope mount (ATM). The test program was initiated in 1967 to determine if the batteries could meet ATM mission requirements and to determine operating characteristics and methods. The ATM system power and charging power for the Ni-Cd secondary batteries is provided by a solar array during the 58-minute daylight portion of the orbit; during the 36-minute night portion of the orbit, the Ni-Cd secondary batteries will supply ATM system power. The test results reflect battery operating characteristics and parameters relative to simulated ATM orbital test conditions. Maximum voltage, charge requirements, capacity, temperature, and cyclic characteristics are presented.

Power spool test, TSH-002, SPTF No. 19

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

McInturff, A.D.

1982-05-28

The data presented in this Technical Memo will pertain to the operating characteristics of Power Spool TSH-002. This spool had a large number of thermometers built into it. These thermometers monitored most of the thermal characteristics of the 5000 A American Magnetics, Inc. vapor-cooled leads used in this power spool. Operating conditions, such as peak temperatures, ramp and dc lead cooling gas flow requirements, voltage as an indicator of stable conditions (ac and dc) and general voltage characteristics (i.e., amount of ice formed outside of leads vs high-pot voltage) were measured and observed. It was found that previous operating conditionsmore » of the power leads influenced the temperature gradients of the leads in certain cases.« less

Man-vehicle systems research facility: Design and operating characteristics

NASA Technical Reports Server (NTRS)

1983-01-01

The Man-Vehicle Systems Research Facility (MVSRF) provides the capability of simulating aircraft (two with full crews), en route and terminal air traffic control and aircrew interactions, and advanced cockpit (1995) display representative of future generations of aircraft, all within the full mission context. The characteristics of this facility derive from research, addressing critical human factors issues that pertain to: (1) information requirements for the utilization and integration of advanced electronic display systems, (2) the interaction and distribution of responsibilities between aircrews and ground controllers, and (3) the automation of aircrew functions. This research has emphasized the need for high fidelity in simulations and for the capability to conduct full mission simulations of relevant aircraft operations. This report briefly describes the MVSRF design and operating characteristics.

An investigation of the operating characteristics of two PTW diamond detectors in photon and electron beams.

PubMed

De Angelis, C; Onori, S; Pacilio, M; Cirrone, G A P; Cuttone, G; Raffaele, L; Bucciolini, M; Mazzocchi, S

2002-02-01

The dosimetric properties of two PTW Riga diamond detectors type 60003 were studied in high-energy photon and electron therapy beam. Properties under study were current-voltage characteristic, polarization effect, time stability of response, dose response, dose-rate dependence, temperature stability, and beam quality dependence of the sensitivity factor. Differences were shown between the two detectors for most of the previous properties. Also, the observed behavior was, to some extent, different from what was reported in the PTW technical specifications. The necessity to characterize each diamond detector individually was addressed.

Quantifying physical characteristics of wildland fuels using the fuel characteristic classification system.

Treesearch

Cynthia L. Riccardi; Susan J. Prichard; David V. Sandberg; Roger D. Ottmar

2007-01-01

Wildland fuel characteristics are used in many applications of operational fire predictions and to understand fire effects and behaviour. Even so, there is a shortage of information on basic fuel properties and the physical characteristics of wildland fuels. The Fuel Characteristic Classification System (FCCS) builds and catalogues fuelbed descriptions based on...

Exploring Alternative Characteristic Curve Approaches to Linking Parameter Estimates from the Generalized Partial Credit Model.

ERIC Educational Resources Information Center

Roberts, James S.; Bao, Han; Huang, Chun-Wei; Gagne, Phill

Characteristic curve approaches for linking parameters from the generalized partial credit model were examined for cases in which common (anchor) items are calibrated separately in two groups. Three of these approaches are simple extensions of the test characteristic curve (TCC), item characteristic curve (ICC), and operating characteristic curve…

7 CFR 1710.252 - Construction work plans-power supply borrowers.

Code of Federal Regulations, 2012 CFR

2012-01-01

... operating systems of supporting power pools and to connect with adjacent power suppliers; (4) Improvements..., new substations and substation improvements and replacements, and Systems Control and Data Acquisition... include studies of load flows, voltage regulation, and stability characteristics to demonstrate system...

7 CFR 1710.252 - Construction work plans-power supply borrowers.

Code of Federal Regulations, 2014 CFR

2014-01-01

... operating systems of supporting power pools and to connect with adjacent power suppliers; (4) Improvements..., new substations and substation improvements and replacements, and Systems Control and Data Acquisition... include studies of load flows, voltage regulation, and stability characteristics to demonstrate system...

7 CFR 1710.252 - Construction work plans-power supply borrowers.

Code of Federal Regulations, 2011 CFR

2011-01-01

... operating systems of supporting power pools and to connect with adjacent power suppliers; (4) Improvements..., new substations and substation improvements and replacements, and Systems Control and Data Acquisition... include studies of load flows, voltage regulation, and stability characteristics to demonstrate system...

7 CFR 1710.252 - Construction work plans-power supply borrowers.

Code of Federal Regulations, 2010 CFR

2010-01-01

... operating systems of supporting power pools and to connect with adjacent power suppliers; (4) Improvements..., new substations and substation improvements and replacements, and Systems Control and Data Acquisition... include studies of load flows, voltage regulation, and stability characteristics to demonstrate system...

7 CFR 1710.252 - Construction work plans-power supply borrowers.

Code of Federal Regulations, 2013 CFR

2013-01-01

... operating systems of supporting power pools and to connect with adjacent power suppliers; (4) Improvements..., new substations and substation improvements and replacements, and Systems Control and Data Acquisition... include studies of load flows, voltage regulation, and stability characteristics to demonstrate system...

Space station executive summary

NASA Technical Reports Server (NTRS)

1972-01-01

An executive summary of the modular space station study is presented. The subjects discussed are: (1) design characteristics, (2) experiment program, (3) operations, (4) program description, and (5) research implications. The modular space station is considered a candidate payload for the low cost shuttle transportation system.

Disturbance characteristics of half-selected cells in a cross-point resistive switching memory array

NASA Astrophysics Data System (ADS)

Chen, Zhe; Li, Haitong; Chen, Hong-Yu; Chen, Bing; Liu, Rui; Huang, Peng; Zhang, Feifei; Jiang, Zizhen; Ye, Hongfei; Gao, Bin; Liu, Lifeng; Liu, Xiaoyan; Kang, Jinfeng; Wong, H.-S. Philip; Yu, Shimeng

2016-05-01

Disturbance characteristics of cross-point resistive random access memory (RRAM) arrays are comprehensively studied in this paper. An analytical model is developed to quantify the number of pulses (#Pulse) the cell can bear before disturbance occurs under various sub-switching voltage stresses based on physical understanding. An evaluation methodology is proposed to assess the disturb behavior of half-selected (HS) cells in cross-point RRAM arrays by combining the analytical model and SPICE simulation. The characteristics of cross-point RRAM arrays such as energy consumption, reliable operating cycles and total error bits are evaluated by the methodology. A possible solution to mitigate disturbance is proposed.

Vertical PM10 Characteristics and their Relation with Tropospheric Meteorology over Hong Kong

NASA Astrophysics Data System (ADS)

Hei Tong, Cheuk

2016-04-01

Small particulates or PM10, those with aerodynamic diameters less than 10 mm, can cause long term impairment to human health as they can penetrate deep and deposit on the wall of the respiratory system. Hong Kong receives significant concentration of cross-boundary particulates but at the same time produce domestic pollutants which altogether contribute to the total pollution problem. Recent research interest is paying more attention on the vertical characteristic of PM in the lower atmosphere as possible correlations exist along different altitude. Besides, there exists potential relationship between PM concentration aloft and the high-level weather condition. Yet, most studies focus only up to around 200 meters above sea level due to the proposed significance and the lack of technology. Undoubtedly, this is not enough in investigating the relation between vertical atmospheric profile and PM vertical characteristics. New technology development has allowed measuring PM concentration along the vertical atmospheric profile up to tropopause. This measurement relies on the Atmospheric Light Detection and Ranging (LiDAR) which operates using the radar principle to detect Rayleigh and Mie scattering from atmospheric gas and aerosols. The research involves (1) study of the seasonal vertical PM10 characteristics in five studying site of Hong Kong covering urban, suburban and rural area; (2) the relationship of the PM10 characteristics with meteorological parameters; (3) the vertical PM10 characteristics under the approach of tropical cyclones. A portable Micro Pulse Lidar (MPL) is adopted to collect PM data aloft while surface PM data is collected from ground stations. High-level meteorology data is received from Hong Kong Observatory. Statistical analyses are operated to investigate the correlation between weather conditions and PM concentration along the vertical profile. The research study is divided in phrases. The ultimate goal of the study is to develop models simulating high-level PM concentration under different meteorological conditions and predict the impacts under global and urban climate change. Keywords: PM10; High level meteorology; Seasonal variations; Tropical cyclone; Hong Kong; LiDAR

Procalcitonin as a diagnostic test for sepsis in critically ill adults and after surgery or trauma: a systematic review and meta-analysis.

PubMed

Uzzan, Bernard; Cohen, Régis; Nicolas, Patrick; Cucherat, Michel; Perret, Gérard-Yves

2006-07-01

To quantify the accuracy of serum procalcitonin as a diagnostic test for sepsis, severe sepsis, or septic shock in adults in intensive care units or after surgery or trauma, alone and compared with C-reactive protein. To draw and compare the summary receiver operating characteristics curves for procalcitonin and C-reactive protein from the literature. MEDLINE (keywords: procalcitonin, intensive care, sepsis, postoperative sepsis, trauma); screening of the literature. Meta-analysis of all 49 published studies in medical, surgical, or polyvalent intensive care units or postoperative wards. Children, medical patients, and immunocompromised patients were excluded. Thirty-three studies fulfilled inclusion criteria (3,943 patients, 1,828 males, 922 females; mean age: 56.1 yrs; 1,825 patients with sepsis, severe sepsis, or septic shock; 1,545 with only systemic inflammatory response syndrome); eight studies could not be analyzed statistically. Global mortality rate was 29.3%. Global odds ratios for diagnosis of infection complicated by systemic inflammation were 15.7 for the 25 studies (2,966 patients) using procalcitonin (95% confidence interval, 9.1-27.1) and 5.4 for the 15 studies (1,322 patients) using C-reactive protein (95% confidence interval, 3.2-9.2). The summary receiver operating characteristics curve for procalcitonin was better than for C-reactive protein. In the 15 studies using both markers, the Q* value (intersection of summary receiver operating characteristics curve with the diagonal line where sensitivity equals specificity) was significantly higher for procalcitonin than for C-reactive protein (0.78 vs. 0.71, p = .02), the former test showing better accuracy. Procalcitonin represents a good biological diagnostic marker for sepsis, severe sepsis, or septic shock, difficult diagnoses in critically ill patients. Procalcitonin is superior to C-reactive protein. Procalcitonin should be included in diagnostic guidelines for sepsis and in clinical practice in intensive care units.

Operations Analysis of the 2nd Generation Reusable Launch Vehicle

NASA Technical Reports Server (NTRS)

Noneman, Steven R.; Smith, C. A. (Technical Monitor)

2002-01-01

The Space Launch Initiative (SLI) program is developing a second-generation reusable launch vehicle. The program goals include lowering the risk of loss of crew to 1 in 10,000 and reducing annual operations cost to one third of the cost of the Space Shuttle. The SLI missions include NASA, military and commercial satellite launches and crew and cargo launches to the space station. The SLI operations analyses provide an assessment of the operational support and infrastructure needed to operate candidate system architectures. Measures of the operability are estimated (i.e. system dependability, responsiveness, and efficiency). Operations analysis is used to determine the impact of specific technologies on operations. A conceptual path to reducing annual operations costs by two thirds is based on key design characteristics, such as reusability, and improved processes lowering labor costs. New operations risks can be expected to emerge. They can be mitigated with effective risk management with careful identification, assignment, tracking, and closure. SLI design characteristics such as nearly full reusability, high reliability, advanced automation, and lowered maintenance and servicing coupled with improved processes are contributors to operability and large operating cost reductions.

Victim countries of transnational terrorism: an empirical characteristics analysis.

PubMed

Elbakidze, Levan; Jin, Yanhong

2012-12-01

This study empirically investigates the association between country-level socioeconomic characteristics and risk of being victimized in transnational terrorism events. We find that a country's annual financial contribution to the U.N. general operating budget has a positive association with the frequency of being victimized in transnational terrorism events. In addition, per capita GDP, political freedom, and openness to trade are nonlinearly related to the frequency of being victimized in transnational terrorism events. © 2012 Society for Risk Analysis.

Strategies for the study of flightcrew behavior

NASA Technical Reports Server (NTRS)

Helmreich, Robert L.

1991-01-01

The performance of any flightcrew at any given time is determined by multiple factors ranging from characteristics of individual crewmembers to the regulations governing flight operations. Attention is given to microcoding of communications, survey data on crewmember attitudes as indicators of culture and crew resource management (CRM) training effects, and systematic observation of crew behavior. Consideration is given to advanced CRM training of evaluators, analyses of crew behavior by aircraft type and characteristics, and survey data on crew reactions to line oriented flight training.

Polarization characteristic of a room-temperature Co:MgF2 laser.

PubMed

Zhang, Zengming M; Cui, Yiben B; Li, Fuli L; Zhang, Guobin B; Pu, Qirong R; Xu, Gaojie J

2002-02-20

A study of the polarization characteristic of a Co:MgF2 laser with a 1320-nm YAG pumping laser at room temperature is reported. The thresholds, output energies, and efficiencies of the laser are given at the various polarization states. The more intensive emission is in the pi-polarization pump laser and sigma-polarization laser operation. Performances of the Co:MgF2 lasers are similar for the polarized and unpolarized laser pumping along the optical axis of the crystal.

Adolescent peer group identification and characteristics: A review of the literature

PubMed Central

Sussman, Steve; Pokhrel, Pallav; Ashmore, Richard D.; Brown, B. Bradford

2011-01-01

This study provides an exhaustive review of 44 peer-reviewed quantitative or qualitative data-based peer-reviewed studies completed on adolescent peer group identification. Adolescent peer group identification is one’s self-perceived or other-perceived membership in discrete teenage peer groups. The studies reviewed suggest that adolescent peer groups consist of five general categories differentiable by lifestyle characteristics: Elites, Athletes, Academics, Deviants, and Others. We found that the Deviant adolescent group category reported relatively greater participation in drug use and other problem behaviors across studies, whereas Academics and Athletes exhibited the least participation in these problem behaviors. Additional research is needed in this arena to better understand the operation of adolescent group labels. PMID:17188815

Open-set speaker identification with diverse-duration speech data

NASA Astrophysics Data System (ADS)

Karadaghi, Rawande; Hertlein, Heinz; Ariyaeeinia, Aladdin

2015-05-01

The concern in this paper is an important category of applications of open-set speaker identification in criminal investigation, which involves operating with short and varied duration speech. The study presents investigations into the adverse effects of such an operating condition on the accuracy of open-set speaker identification, based on both GMMUBM and i-vector approaches. The experiments are conducted using a protocol developed for the identification task, based on the NIST speaker recognition evaluation corpus of 2008. In order to closely cover the real-world operating conditions in the considered application area, the study includes experiments with various combinations of training and testing data duration. The paper details the characteristics of the experimental investigations conducted and provides a thorough analysis of the results obtained.

PC-403: Pioneer Venus multiprobe spacecraft mission operational characteristics document, volume 1

NASA Technical Reports Server (NTRS)

Barker, F. C.

1978-01-01

The operational characteristics of the multiprobe system and its subsystem are described. System level, description of the nominal phases, system interfaces, and the capabilities and limitations of system level performance are presented. Bus spacecraft functional and operational descriptions at the subsystem and unit level are presented. The subtleties of nominal operation as well as detailed capabilities and limitations beyond nominal performance are discussed. A command and telemetry logic flow diagram for each subsystem is included. Each diagram identifies in symbolic logic all signal conditioning encountered along each command signal path into, and each telemetry signal path out of the subsystem.

LMS tables for waist circumference and waist–height ratio in Colombian adults: analysis of nationwide data 2010

PubMed Central

Ramírez-Vélez, R; Correa-Bautista, J E; Martínez-Torres, J; Méneses-Echavez, J F; González-Ruiz, K; González-Jiménez, E; Schmidt-RioValle, J; Lobelo, F

2016-01-01

Background/Objectives: Indices predictive of central obesity include waist circumference (WC) and waist-to-height ratio (WHtR). These data are lacking for Colombian adults. This study aims at establishing smoothed centile charts and LMS tables for WC and WHtR; appropriate cutoffs were selected using receiver-operating characteristic analysis based on data from the representative sample. Subjects/Methods: We used data from the cross-sectional, national representative nutrition survey (ENSIN, 2010). A total of 83 220 participants (aged 20–64) were enroled. Weight, height, body mass index (BMI), WC and WHtR were measured and percentiles calculated using the LMS method (L (curve Box-Cox), M (curve median), and S (curve coefficient of variation)). Receiver operating characteristics curve analyses were used to evaluate the optimal cutoff point of WC and WHtR for overweight and obesity based on WHO definitions. Results: Reference values for WC and WHtR are presented. Mean WC and WHtR increased with age for both genders. We found a strong positive correlation between WC and BMI (r=0.847, P< 0.01) and WHtR and BMI (r=0.878, P<0.01). In obese men, the cutoff point value is 96.6 cm for the WC. In women, the cutoff point value is 91.0 cm for the WC. Receiver operating characteristic curve for WHtR was also obtained and the cutoff point value of 0.579 in men, and in women the cutoff point value was 0.587. A high sensitivity and specificity were obtained. Conclusions: This study presents first reference values of WC and WHtR for Colombians aged 20–64. Through LMS tables for adults, we hope to provide quantitative tools to study obesity and its complications. PMID:27026425

The role of non-operating income in community benefit provision by not-for-profit hospitals.

PubMed

Song, Paula H; McCullough, Jeffrey S; Reiter, Kristin L

2013-01-01

Not-for-profit hospitals are under increased public scrutiny for providing what some view as insufficient levels of community benefit compared to their tax-exempt benefits. One potential driver of community benefit is financial surplus, which arises from both patient care (operating) activities and non-patient care (non-operating) activities. This study addresses the effect of hospitals' non-operating income on not-for-profit hospitals' provision of community benefit. The study sample includes 217 unique not-for-profit, non-governmental, general, acute care hospitals in California between 1997 and 2010 that filed annual reports with the California Office of Statewide Health Planning and Development (OSHPD). We model the effect of hospitals' operating and non-operating incomes on hospitals' community benefit, controlling for observable hospital characteristics such as scale and system membership, local competition, time trends, and hospital fixed effects. Our results indicate that non-operating income has no effect on levels of community benefit provided by not-for-profit hospitals. This finding suggests that not-for-profit hospitals budget for uncompensated care at levels that are prioritized over other potential investments if non-operating income falls, but remain fixed if non-operating income rises.

Performance limitations of bilateral force reflection imposed by operator dynamic characteristics

NASA Technical Reports Server (NTRS)

Chapel, Jim D.

1989-01-01

A linearized, single-axis model is presented for bilateral force reflection which facilitates investigation into the effects of manipulator, operator, and task dynamics, as well as time delay and gain scaling. Structural similarities are noted between this model and impedance control. Stability results based upon this model impose requirements upon operator dynamic characteristics as functions of system time delay and environmental stiffness. An experimental characterization reveals the limited capabilities of the human operator to meet these requirements. A procedure is presented for determining the force reflection gain scaling required to provide stability and acceptable operator workload. This procedure is applied to a system with dynamics typical of a space manipulator, and the required gain scaling is presented as a function of environmental stiffness.

Modeling the effect of operator and passenger characteristics on the fatality risk of motorcycle crashes

PubMed Central

Tavakoli Kashani, Ali; Rabieyan, Rahim; Besharati, Mohammad Mehdi

2016-01-01

Abstract: Background: In Iran more than 25% of crash fatalities belong to motorcycle operators and passengers in the recent years, from which about 20% are related to passenger fatalities. Methods: The aim of this study was to investigate the motorcycle operator and passenger characteristics as well as other contributory factors that may affect the fatality risk of motorcyclists involved in traffic crashes. To this end, motorcycle crash data between 2009 and 2012 was extracted from Iran traffic crash database and a logistic regression analysis was performed to obtain odds ratio estimates for each of the study variables. Results: The fatality risk of motorcyclists has a direct relationship with the number of pillion passengers carried. Results also indicate that the amount of increase in the likelihood of having a fatality in a motorcycles crash is considerably higher when the operator is accompanied by a male passenger of the same age. Furthermore, results showed that if the crash is occurred in the darkness, on curves, in rural areas and on highways, then the crash would be more likely to be fatal. Moreover, the head-on collisions, older operators, unlicensed operators and not using a safety helmet were found to increase the likelihood of a fatality in a motorcycle crash. Conclusions: Preventative measures such as, imposing stricter rules regarding safety helmet usage and confining the number of pillion passengers to one, might be implemented to reduce the fatality risk in motorcycle crashes. In addition, more appropriate infrastructures for penalizing offending motorcyclists could also reduce the frequency of law violations such as not wearing helmet or riding without motorcycle license, which in turn, would result into a reduction in the fatality risk of motorcycle crashes. PMID:26420217

Describing an Environment for a Self-Sustaining Technology Transfer Service in a Small Research Budget University: A Case Study

ERIC Educational Resources Information Center

Nieb, Sharon Lynn

2014-01-01

This single-site qualitative study sought to identify the characteristics that contribute to the self sustainability of technology transfer services at universities with small research budgets through a case study analysis of a small research budget university that has been operating a financially self-sustainable technology transfer service for…

Characteristics of Urban Enrollees Entering the Job Corps. Longitudinal Manpower Evaluation Studies.

ERIC Educational Resources Information Center

Office of Economic Opportunity, Washington, DC. Office of Planning, Research, and Evaluation.

This paper is the first in a series describing the results of the Longitudinal Manpower Study, a national study of four major manpower programs as they operate in large urban areas. Included in the paper are data gained from the responses of 1,236 Job Corps enrollees concerning their reasons for joining the program, their demographic…

Maclaurin symmetric mean operators of linguistic intuitionistic fuzzy numbers and their application to multiple-attribute decision-making

NASA Astrophysics Data System (ADS)

Liu, Peide; Qin, Xiyou

2017-11-01

Linguistic intuitionistic fuzzy number (LIFN) is a special intuitionistic fuzzy number which can more easily describe the vagueness existing in the real decision-making. Maclaurin symmetric mean (MSM) operator has the characteristic of considering the interrelationships among any number of input parameters. In this paper, we extended the MSM operator to the LIFNs and some extended MSM operators for LIFNs were proposed, some new decision-making methods were developed. Firstly, we introduced the definition, score function, properties and operational rules of the LIFNs. Then, we proposed some linguistic intuitionistic fuzzy MSM operators, such as linguistic intuitionistic fuzzy Maclaurin symmetric mean operator, weighted linguistic intuitionistic fuzzy Maclaurin symmetric mean (WLIFMSM) operator, linguistic intuitionistic fuzzy dual Maclaurin symmetric mean operator, weighted linguistic intuitionistic fuzzy dual Maclaurin symmetric mean (WLIFDMSM) operator. In the meantime, we studied some important properties of these operators, and developed some methods based on WLIFMSM operator and WLIFDMSM operator for multi-attribute decision-making. Finally, we use an example to demonstrate the effectiveness of the proposed methods.

A Satellite Mortality Study to Support Space Systems Lifetime Prediction

NASA Technical Reports Server (NTRS)

Fox, George; Salazar, Ronald; Habib-Agahi, Hamid; Dubos, Gregory

2013-01-01

Estimating the operational lifetime of satellites and spacecraft is a complex process. Operational lifetime can differ from mission design lifetime for a variety of reasons. Unexpected mortality can occur due to human errors in design and fabrication, to human errors in launch and operations, to random anomalies of hardware and software or even satellite function degradation or technology change, leading to unrealized economic or mission return. This study focuses on data collection of public information using, for the first time, a large, publically available dataset, and preliminary analysis of satellite lifetimes, both operational lifetime and design lifetime. The objective of this study is the illustration of the relationship of design life to actual lifetime for some representative classes of satellites and spacecraft. First, a Weibull and Exponential lifetime analysis comparison is performed on the ratio of mission operating lifetime to design life, accounting for terminated and ongoing missions. Next a Kaplan-Meier survivor function, standard practice for clinical trials analysis, is estimated from operating lifetime. Bootstrap resampling is used to provide uncertainty estimates of selected survival probabilities. This study highlights the need for more detailed databases and engineering reliability models of satellite lifetime that include satellite systems and subsystems, operations procedures and environmental characteristics to support the design of complex, multi-generation, long-lived space systems in Earth orbit.

Peritumoral Artery Scoring System: a Novel Scoring System to Predict Renal Function Outcome after Laparoscopic Partial Nephrectomy.

PubMed

Zhang, Ruiyun; Wu, Guangyu; Huang, Jiwei; Shi, Oumin; Kong, Wen; Chen, Yonghui; Xu, Jianrong; Xue, Wei; Zhang, Jin; Huang, Yiran

2017-06-06

The present study aimed to assess the impact of peritumoral artery characteristics on renal function outcome prediction using a novel Peritumoral Artery Scoring System based on computed tomography arteriography. Peritumoral artery characteristics and renal function were evaluated in 220 patients who underwent laparoscopic partial nephrectomy and then validate in 51 patients with split and total glomerular filtration rate (GFR). In particular, peritumoral artery classification and diameter were measured to assign arteries into low, moderate, and high Peritumoral Artery Scoring System risk categories. Univariable and multivariable logistic regression analyses were then used to determine risk factors for major renal functional decline. The Peritumoral Artery Scoring System and four other nephrometry systems were compared using receiver operating characteristic curve analysis. The Peritumoral Artery Scoring System was significantly superior to the other systems for predicting postoperative renal function decline (p < 0.001). In receiver operating characteristic analysis, our category system was a superior independent predictor of estimated glomerular filtration rate (eGFR) decline (area-under-the-curve = 0.865, p < 0.001) and total GFR decline (area-under-the-curve = 0.796, p < 0.001), and split GFR decline (area-under-the-curve = 0.841, p < 0.001). Peritumoral artery characteristics were independent predictors of renal function outcome after laparoscopic partial nephrectomy.

Etude de la physico-chime d'un magnetoplasma de chlore pour la gravure sous-micrometrique

NASA Astrophysics Data System (ADS)

Pauna, Olivier Daniel

The aim of this thesis is to achieve a better understanding of physical and chemical phenomena occurring in a high-density plasma designed for sub-micron etching of thin films. The plasma is produced in chlorine by means of an electromagnetic surface wave and it can be confined by a uniform static magnetic field. The flexibility offered by the reactor in terms of operating conditions makes possible a parametric study of the influence of the magnetic confinement on the plasma characteristics. Thus, we have examined the plasma properties by means of several diagnostics techniques, including electrostatic probes, laser photodetachment of negative ions, ion acoustic wave propagation and optical emission spectroscopy. First, we investigated the influence of the operating conditions on the spatial properties of the plasma; this includes electric characteristics (electrons, positive and negative ions) as well as chemical characteristics (reactive neutrals). Second, we studied the impact of the reactor aspect ratio (i.e. reactor length/radius ratio) on both electrical and chemical characteristics. Together with these experimental studies, we have developed a bidimensional fluid model, by solving self-consistently the first two moments of Bolzmann equation and Poisson's equation. Using a semi-implicit scheme, it was possible to maintain a short computation time and to use this model to investigate a diffusion plasma in an electropositive gas. We were thus able to estimate the value of the diffusion coefficient in the direction perpendicular to the magnetic field. The results thus obtained are in good qualitative agreement with the diffusion coefficient proposed by Liebermann and Lichtenberg.

Assessing the Classification Accuracy of Early Numeracy Curriculum-Based Measures Using Receiver Operating Characteristic Curve Analysis

ERIC Educational Resources Information Center

Laracy, Seth D.; Hojnoski, Robin L.; Dever, Bridget V.

2016-01-01

Receiver operating characteristic curve (ROC) analysis was used to investigate the ability of early numeracy curriculum-based measures (EN-CBM) administered in preschool to predict performance below the 25th and 40th percentiles on a quantity discrimination measure in kindergarten. Areas under the curve derived from a sample of 279 students ranged…

Characteristics of the Romanian energy market

NASA Astrophysics Data System (ADS)

Stet, M.

2017-05-01

This paper highlights the main characteristics of the energy market in Romania. Starting from the mode of organization and operation of the electricity market, there are revealed prices and tariffs for electricity for different categories of customers and their evolution in time. There are pointed also ways of setting electricity prices and tariffs, taking into account the expenditures actually recorded by economic operators.

Transfer function tests of the Joy longwall shearer

NASA Technical Reports Server (NTRS)

Fisher, P. H., Jr.

1978-01-01

A series of operational tests was performed on the Joy longwall shearer located at the Bureau of Mines in Bructon, Pennsylvania. The purpose of these tests was to determine the transfer function and operational characteristics of the system. These characteristics will be used to generate a simulation model of the longwall shearer used in the development of the closed-loop vertical control system.

Study of the application of hydrogen fuel to long-range subsonic transport aircraft, volume 2

NASA Technical Reports Server (NTRS)

Brewer, G. D.; Morris, R. E.; Lange, R. H.; Moore, J. W.

1975-01-01

The feasibility, practicability, and potential advantages/disadvantages of using liquid hydrogen as fuel in long range, subsonic transport aircraft of advanced design were studied. Both passenger and cargo-type aircraft were investigated. To provide a valid basis for comparison, conventional hydrocarbon (Jet A) fueled aircraft were designed to perform identical missions using the same advanced technology and meeting the same operational constraints. The liquid hydrogen and Jet A fueled aircraft were compared on the basis of weight, size, energy utilization, cost, noise, emissions, safety, and operational characteristics. A program of technology development was formulated.

Laparoscopic repair of giant paraesophageal hernia: are there factors associated with anatomic recurrence?

PubMed

Antiporda, Michael; Veenstra, Benjamin; Jackson, Chloe; Kandel, Pujan; Daniel Smith, C; Bowers, Steven P

2018-02-01

Repair of giant paraesophageal hernia (PEH) is associated with a favorably high rate of symptom improvement; however, rates of recurrence by objective measures remain high. Herein we analyze our experience with laparoscopic giant PEH repair to determine what factors if any can predict anatomic recurrence. We prospectively collected data on PEH characteristics, variations in operative techniques, and surgeon factors for 595 patients undergoing laparoscopic PEH repair from 2008 to 2015. Upper GI study was performed at 6 months postoperatively and selectively thereafter-any supra-diaphragmatic stomach was considered hiatal hernia recurrence. Exclusion criteria included revisional operation (22.4%), size <5 cm (17.6%), inadequate follow-up (17.8%), and confounding concurrent operations (6.9%). Inclusion criteria were met by 202 patients (31% male, median age 71 years, and median BMI 28.7). At a median follow-up of 6 months (IQR 6-12), overall anatomic recurrence rate was 34.2%. Symptom recurrence rate was 9.9% and revisional operation was required in ten patients (4.9%). Neither patient demographics nor PEH characteristics (size, presence of Cameron erosions, esophagitis, or Barrett's) correlated with anatomic recurrence. Technical factors at operation (mobilized intra-abdominal length of esophagus, Collis gastroplasty, number of anterior/posterior stitches, use of crural buttress, use of pledgeted or mattress sutures, or gastrostomy) were also not correlated with recurrence. Regarding surgeon factors, annual volume of fewer than ten cases per year was associated with increased risk of anatomic failure (54 vs 33%, P = 0.02). Multivariate analysis identified surgeon experience (<10 cases per year) as an independent factor associated with early hiatal hernia recurrence (OR 3.7, 95% CI 1.34-10.9). Laparoscopic repair of giant PEH is associated with high anatomic recurrence rate but excellent symptom control. PEH characteristics and technical operative variables do not appear to significantly affect rates of recurrence. In contrast, surgeon volume does appear to contribute significantly to durability of repair.

Target Identification Support and Location Support Among Teams of Unmanned Systems Operators

DTIC Science & Technology

2008-12-01

effectiveness and performance, many studies have highlighted the importance of attending to team process (Campion, Medsker, & Higgs, 1993, Campion, Papper ...work groups. Personnel Psychology, 46, 823-850. Campion, M., Papper , E., & Medsker, G., 1996: Relations between work team characteristics and

Orbit Transfer Vehicle (OTV) advanced expander cycle engine point design study, volume 2

NASA Technical Reports Server (NTRS)

1981-01-01

The engine requirements are emphasized and include: high specific impulse within a restricted installed length constraint, long life, multiple starts, different thrust levels, and man-rated reliability. The engine operating characteristics and the major component analytical design are summarized.

Solar power satellite system definition study. Volume 5, phase 1: Executive summary

NASA Technical Reports Server (NTRS)

1979-01-01

An analysis of the solar power satellite system is presented. Performance, cost, and operational characteristics are assessed. The photovoltaic system is described and investigated. Alternative construction concepts are discussed. The structural bay configuration is presented along with the antenna structure options.

Estimating time-dependent ROC curves using data under prevalent sampling.

PubMed

Li, Shanshan

2017-04-15

Prevalent sampling is frequently a convenient and economical sampling technique for the collection of time-to-event data and thus is commonly used in studies of the natural history of a disease. However, it is biased by design because it tends to recruit individuals with longer survival times. This paper considers estimation of time-dependent receiver operating characteristic curves when data are collected under prevalent sampling. To correct the sampling bias, we develop both nonparametric and semiparametric estimators using extended risk sets and the inverse probability weighting techniques. The proposed estimators are consistent and converge to Gaussian processes, while substantial bias may arise if standard estimators for right-censored data are used. To illustrate our method, we analyze data from an ovarian cancer study and estimate receiver operating characteristic curves that assess the accuracy of the composite markers in distinguishing subjects who died within 3-5 years from subjects who remained alive. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Whole-Lesion Histogram Analysis of Apparent Diffusion Coefficient for the Assessment of Cervical Cancer.

PubMed

Guan, Yue; Shi, Hua; Chen, Ying; Liu, Song; Li, Weifeng; Jiang, Zhuoran; Wang, Huanhuan; He, Jian; Zhou, Zhengyang; Ge, Yun

2016-01-01

The aim of this study was to explore the application of whole-lesion histogram analysis of apparent diffusion coefficient (ADC) values of cervical cancer. A total of 54 women (mean age, 53 years) with cervical cancers underwent 3-T diffusion-weighted imaging with b values of 0 and 800 s/mm prospectively. Whole-lesion histogram analysis of ADC values was performed. Paired sample t test was used to compare differences in ADC histogram parameters between cervical cancers and normal cervical tissues. Receiver operating characteristic curves were constructed to identify the optimal threshold of each parameter. All histogram parameters in this study including ADCmean, ADCmin, ADC10%-ADC90%, mode, skewness, and kurtosis of cervical cancers were significantly lower than those of normal cervical tissues (all P < 0.0001). ADC90% had the largest area under receiver operating characteristic curve of 0.996. Whole-lesion histogram analysis of ADC maps is useful in the assessment of cervical cancer.

A Primer on Receiver Operating Characteristic Analysis and Diagnostic Efficiency Statistics for Pediatric Psychology: We Are Ready to ROC

PubMed Central

2014-01-01

Objective To offer a practical demonstration of receiver operating characteristic (ROC) analyses, diagnostic efficiency statistics, and their application to clinical decision making using a popular parent checklist to assess for potential mood disorder. Method Secondary analyses of data from 589 families seeking outpatient mental health services, completing the Child Behavior Checklist and semi-structured diagnostic interviews. Results Internalizing Problems raw scores discriminated mood disorders significantly better than did age- and gender-normed T scores, or an Affective Problems score. Internalizing scores <8 had a diagnostic likelihood ratio <0.3, and scores >30 had a diagnostic likelihood ratio of 7.4. Conclusions This study illustrates a series of steps in defining a clinical problem, operationalizing it, selecting a valid study design, and using ROC analyses to generate statistics that support clinical decisions. The ROC framework offers important advantages for clinical interpretation. Appendices include sample scripts using SPSS and R to check assumptions and conduct ROC analyses. PMID:23965298

A primer on receiver operating characteristic analysis and diagnostic efficiency statistics for pediatric psychology: we are ready to ROC.

PubMed

Youngstrom, Eric A

2014-03-01

To offer a practical demonstration of receiver operating characteristic (ROC) analyses, diagnostic efficiency statistics, and their application to clinical decision making using a popular parent checklist to assess for potential mood disorder. Secondary analyses of data from 589 families seeking outpatient mental health services, completing the Child Behavior Checklist and semi-structured diagnostic interviews. Internalizing Problems raw scores discriminated mood disorders significantly better than did age- and gender-normed T scores, or an Affective Problems score. Internalizing scores <8 had a diagnostic likelihood ratio <0.3, and scores >30 had a diagnostic likelihood ratio of 7.4. This study illustrates a series of steps in defining a clinical problem, operationalizing it, selecting a valid study design, and using ROC analyses to generate statistics that support clinical decisions. The ROC framework offers important advantages for clinical interpretation. Appendices include sample scripts using SPSS and R to check assumptions and conduct ROC analyses.

New insights into comparison between synthetic and practical municipal wastewater in cake layer characteristic analysis of membrane bioreactor.

PubMed

Zhou, Lijie; Zhuang, Wei-Qin; Wang, Xin; Yu, Ke; Yang, Shufang; Xia, Siqing

2017-11-01

In previous studies, cake layer analysis in membrane bioreactor (MBR) was both carried out with synthetic and practical municipal wastewater (SMW and PMW), leading to different results. This study aimed to identify the comparison between SMW and PMW in cake layer characteristic analysis of MBR. Two laboratory-scale anoxic/oxic MBRs were operated for over 90days with SMW and PMW, respectively. Results showed that PMW led to rough cake layer surface with particles, and the aggravation of cake layer formation with thinner and denser cake layer. Additionally, inorganic components, especially Si and Al, in PMW accumulated into cake layer and strengthened the cake layer structure, inducing severer biofouling. However, SMW promoted bacterial metabolism during cake layer formation, thus aggravated the accumulation of organic components into cake layer. Therefore, SMW highlighted the organic components in cake layer, but weakened the inorganic functions in practical MBR operation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Organizational Characteristics Associated With Fundraising Performance of Nonprofit Hospitals.

PubMed

Erwin, Cathleen Owens; Landry, Amy Yarbrough

2015-01-01

Fundraising has become increasingly important to nonprofit hospitals as access to capital has grown more difficult and reimbursement for services more complex. This study analyzes the variation in organizational characteristics and fundraising performance among nonprofit acute care hospitals in the United States to identify and measure critical factors related to one key fundraising performance indicator: public support. Results indicate that the presence of an endowment, along with its value, investments in fundraising, and the geographic location of the organization, account for approximately 46% of variance in public support among nonprofit hospitals. The use of a separate foundation for the fundraising operation is not necessarily associated with measures of fundraising success; however, a majority of hospitals do use a foundation, signaling a strategic choice that may be made for numerous reasons. The study results and limitations are discussed and recommendations are made for maximizing the effectiveness of the fundraising enterprise within nonprofit hospitals. Increasing awareness of challenges associated with fundraising success will enhance the strategic management of fundraising operations by hospital executives and board members.

AN EULERIAN-LAGRANGIAN LOCALIZED ADJOINT METHOD FOR THE ADVECTION-DIFFUSION EQUATION

EPA Science Inventory

Many numerical methods use characteristic analysis to accommodate the advective component of transport. Such characteristic methods include Eulerian-Lagrangian methods (ELM), modified method of characteristics (MMOC), and operator splitting methods. A generalization of characteri...

Synthetic battery cycling techniques

NASA Technical Reports Server (NTRS)

Leibecki, H. F.; Thaller, L. H.

1982-01-01

Synthetic battery cycling makes use of the fast growing capability of computer graphics to illustrate some of the basic characteristics of operation of individual electrodes within an operating electrochemical cell. It can also simulate the operation of an entire string of cells that are used as the energy storage subsystem of a power system. The group of techniques that as a class have been referred to as Synthetic Battery Cycling is developed in part to try to bridge the gap of understanding that exists between single cell characteristics and battery system behavior.

Receiver operating characteristic analysis. Application to the study of quantum fluctuation effects in optic nerve of Rana pipiens

PubMed Central

1975-01-01

Receiver operating characteristic (ROC) analysis of nerve messages is described. The hypothesis that quantum fluctuations provide the only limit to the ability of frog ganglion cells to signal luminance change information is examined using ROC analysis. In the context of ROC analysis, the quantum fluctuation hypothesis predicts (a) the detectability of a luminance change signal should rise proportionally to the size of the change, (b) detectability should decrease as the square root of background, an implication of which is the deVries-Rose law, and (c) ROC curves should exhibit a shape particular to underlying Poisson distributions. Each of these predictions is confirmed for the responses of dimming ganglion cells to brief luminance decrements at scotopic levels, but none could have been tested using classical nerve message analysis procedures. PMID:172597

Consumer-operated service organizations: organizational characteristics, community relationships, and the potential for citizenship.

PubMed

Tanenbaum, Sandra J

2012-08-01

Consumer-operated service organizations (COSOs) are independent organizations whose administrative and financial control resides with consumers. Based on a 2008 mail survey and followup interviews conducted in 2009, this study depicts the internal characteristics and external relationships, as well as some relationships between the two, of COSOs in one state. Profiles include on the one hand, governance structures, services provided, sources and levels of funding, etc. and on the other, relationships between COSOs and other actors in the mental health system and the local community. COSOs emerge as more self-governing and community-based than required by certification requirements and as developing internally and externally in tandem. COSOs are not only adjunct or alternative service providers, but also civic associations and loci for the expression of citizenship by mentally ill people.

49 CFR 240.231 - Requirements for locomotive engineers unfamiliar with physical characteristics in other than...

Code of Federal Regulations, 2011 CFR

2011-10-01

... with physical characteristics in other than joint operations. 240.231 Section 240.231 Transportation... Process § 240.231 Requirements for locomotive engineers unfamiliar with physical characteristics in other... characteristics of the territory pursuant to the railroad's certification program. (b) Except as provided in...

49 CFR 240.231 - Requirements for locomotive engineers unfamiliar with physical characteristics in other than...

Code of Federal Regulations, 2010 CFR

2010-10-01

... with physical characteristics in other than joint operations. 240.231 Section 240.231 Transportation... Process § 240.231 Requirements for locomotive engineers unfamiliar with physical characteristics in other... characteristics of the territory pursuant to the railroad's certification program. (b) Except as provided in...

RCS jet-flow field interaction effects on the aerodynamics of the space shuttle orbiter

NASA Technical Reports Server (NTRS)

Rausch, J. R.; Roberge, A. M.

1973-01-01

A study was conducted to determine the external effects caused by operation of the reaction control system during entry of the space shuttle orbiter. The effects of jet plume-external flow interactions were emphasized. Force data were obtained for the basic airframe characteristics plus induced effects when the reaction control system is operating. Resulting control amplification and/or coupling were derived and their effects on the aerodynamic stability and control of the orbiter and the reaction control system thrust were determined.

Simulation of solidification in a Bridgman cell

NASA Technical Reports Server (NTRS)

Dakhoul, Y. M.; Farmer, R. C.

1984-01-01

Bridgman-type crystal growth techniques are attractive methods for producing homogeneous, high-quality infrared detector and junction device materials. However, crystal imperfections and interface shapes still must be controlled through modification of the temperature and concentration gradients created during solidification. The objective of this investigation was to study the temperature fields generated by various cell and heatpipe configurations and operating conditions. Continuum's numerical model of the temperature, species concentrations, and velocity fields was used to describe the thermal characteristics of Bridgman cell operation.

Study of the Synchronous Operation of an Annular Field Reversed Configuration Plasma Device

DTIC Science & Technology

2008-05-05

of pulsed diagnostics were developed to explore the operational characteristics of a 40 -cm outer diameter annular theta pinch and its pre-ionization...Optimized pre-ionization conditions, neutral gas densities, and plasma transition energies were determined for the 40 cm annulus in both argon and xenon...MSNW 100 25 10 10 150 Formation 1985 HBQM U Wash 300 22 5 5 30 Formation 1986 TRX-2 STI 100 24 13 10 100 Confinement 1987 CSS U Wash 100 45 3 40 60

Towards a knowledge-based system to assist the Brazilian data-collecting system operation

NASA Technical Reports Server (NTRS)

Rodrigues, Valter; Simoni, P. O.; Oliveira, P. P. B.; Oliveira, C. A.; Nogueira, C. A. M.

1988-01-01

A study is reported which was carried out to show how a knowledge-based approach would lead to a flexible tool to assist the operation task in a satellite-based environmental data collection system. Some characteristics of a hypothesized system comprised of a satellite and a network of Interrogable Data Collecting Platforms (IDCPs) are pointed out. The Knowledge-Based Planning Assistant System (KBPAS) and some aspects about how knowledge is organized in the IDCP's domain are briefly described.

Wavelet and receiver operating characteristic analysis of heart rate variability

NASA Astrophysics Data System (ADS)

McCaffery, G.; Griffith, T. M.; Naka, K.; Frennaux, M. P.; Matthai, C. C.

2002-02-01

Multiresolution wavelet analysis has been used to study the heart rate variability in two classes of patients with different pathological conditions. The scale dependent measure of Thurner et al. was found to be statistically significant in discriminating patients suffering from hypercardiomyopathy from a control set of normal subjects. We have performed Receiver Operating Characteristc (ROC) analysis and found the ROC area to be a useful measure by which to label the significance of the discrimination, as well as to describe the severity of heart dysfunction.

An empirical comparison of key statistical attributes among potential ICU quality indicators.

PubMed

Brown, Sydney E S; Ratcliffe, Sarah J; Halpern, Scott D

2014-08-01

Good quality indicators should have face validity, relevance to patients, and be able to be measured reliably. Beyond these general requirements, good quality indicators should also have certain statistical properties, including sufficient variability to identify poor performers, relative insensitivity to severity adjustment, and the ability to capture what providers do rather than patients' characteristics. We assessed the performance of candidate indicators of ICU quality on these criteria. Indicators included ICU readmission, mortality, several length of stay outcomes, and the processes of venous-thromboembolism and stress ulcer prophylaxis provision. Retrospective cohort study. One hundred thirty-eight U.S. ICUs from 2001-2008 in the Project IMPACT database. Two hundred sixty-eight thousand eight hundred twenty-four patients discharged from U.S. ICUs. None. We assessed indicators' (1) variability across ICU-years; (2) degree of influence by patient vs. ICU and hospital characteristics using the Omega statistic; (3) sensitivity to severity adjustment by comparing the area under the receiver operating characteristic curve (AUC) between models including vs. excluding patient variables, and (4) correlation between risk adjusted quality indicators using a Spearman correlation. Large ranges of among-ICU variability were noted for all quality indicators, particularly for prolonged length of stay (4.7-71.3%) and the proportion of patients discharged home (30.6-82.0%), and ICU and hospital characteristics outweighed patient characteristics for stress ulcer prophylaxis (ω, 0.43; 95% CI, 0.34-0.54), venous thromboembolism prophylaxis (ω, 0.57; 95% CI, 0.53-0.61), and ICU readmissions (ω, 0.69; 95% CI, 0.52-0.90). Mortality measures were the most sensitive to severity adjustment (area under the receiver operating characteristic curve % difference, 29.6%); process measures were the least sensitive (area under the receiver operating characteristic curve % differences: venous thromboembolism prophylaxis, 3.4%; stress ulcer prophylaxis, 2.1%). None of the 10 indicators was clearly and consistently correlated with a majority of the other nine indicators. No indicator performed optimally across assessments. Future research should seek to define and operationalize quality in a way that is relevant to both patients and providers.

Hydraulic and separation characteristics of an industrial gas centrifuge calculated with neural networks

NASA Astrophysics Data System (ADS)

Butov, Vladimir; Timchenko, Sergey; Ushakov, Ivan; Golovkov, Nikita; Poberezhnikov, Andrey

2018-03-01

Single gas centrifuge (GC) is generally used for the separation of binary mixtures of isotopes. Processes taking place within the centrifuge are complex and non-linear. Their characteristics can change over time with long-term operation due to wear of the main structural elements of the GC construction. The paper is devoted to the determination of basic operation parameters of the centrifuge with the help of neural networks. We have developed a method for determining the parameters of the industrial GC operation by processing statistical data. In this work, we have constructed a neural network that is capable of determining the main hydraulic and separation characteristics of the gas centrifuge, depending on the geometric dimensions of the gas centrifuge, load value, and rotor speed.

Operational Weight Estimations of Commercial Jet Transport Aircraft

NASA Technical Reports Server (NTRS)

Anderson, Joseph L.

1972-01-01

In evaluating current or proposed commercial transport airplanes, there has not been available a ready means to determine weights so as to compare airplanes within this particular class. This paper describes the development of and presents such comparative tools. The major design characteristics of current American jet transport airplanes were collected, and these data were correlated by means of regression analysis to develop weight relationships for these airplanes as functions of their operational requirements. The characteristics for 23 airplanes were assembled and examined in terms of the effects of the number of people carried, the cargo load, and the operating range. These airplane characteristics were correlated for the airplanes as one of three subclasses, namely the small, twin-engine jet transport, the conventional three- and four-engine jets, and the new wide-body jets.

Contamination avoidance devices for poppettype shutoff valves

NASA Technical Reports Server (NTRS)

Endicott, D. L.

1973-01-01

The determination of the cycle life is reported of the scal closure of a typical poppet-type shutoff valve in an uncontaminated GH2 environment and then compared this component performance with simulated operation with GN2 and LN2 containing controlled amounts of AL2O3 contaminant particles. The original valve design was tested for contamination damage tolerance characteristics under full-flow and cyclic-operating conditions, redesigned to improve the damage tolerance to contaminants, and then retested. The redesigned valve was found to have acceptable tolerance characteristics under all full-flow conditions and cyclic operation with small (25-75 microns) particulate contamination. The tolerance characteristics of the valve under cyclic conditions with large (75-250 microns) particulate contamination was improved but was not found to be completely satisfactory.

Improving patency of coronary conduits "valveless" veins and/or arterial grafts.

PubMed

Lajos, Thomas Z; Robicsek, Francis; Thubrikar, Mano; Urschel, Harold

2007-01-01

Veins used for coronary artery bypass operation have a well-documented limited long-term patency. Internal thoracic artery (ITA) grafts have shown exceptional "durability." Assumptions were made that other arterial conduits have similar characteristics. The purpose of this article is to compare different conduits long-term patency including saphenous veins to other available arterial conduits: inferior epigastric artery (IE), right gastroepiploic artery (RGEA), and radial artery (RA). Recent studies have shown that radial artery bypasses have lower patency rate than saphenous veins. Flow patterns, physiological flow characteristics are reviewed including native vessel disease and area of myocardium supplied. In the case of venous bypasses, the primary culprit of failure seemed to be the quality of the vein itself and the reverse venous valves in the conduit resulting in: (a) trapping-hypertension, (b) thrombosis, (c) turbulence, (d) intimal damage, (e) mismatching in size. Clinical follow-up of our patients up to 8 to 11 years (average 8.9 years) have proved the superior characteristics of the so-called "good veins." In a retrospective study of 436 patients sequential, valveless veins patency was 88.6% versus 72% of reversed valvular segments (p < 0.01). Patients' survival seemed to be significantly improved if these veins were combined with ITA grafts. Patients' survival with one valveless limb HS + ITA was 78% versus HS + SV 52% (p < or = 0.0017) and HS + ITA versus HS + ITA + SV (p < 0.0057). Selective decision-making of the surgeon at the time of the operation is required to choose the best conduit to be able to perform the best operation with the best long-term result.

Energy Performance and Optimal Control of Air-conditioned Buildings Integrated with Phase Change Materials

NASA Astrophysics Data System (ADS)

Zhu, Na

This thesis presents an overview of the previous research work on dynamic characteristics and energy performance of buildings due to the integration of PCMs. The research work on dynamic characteristics and energy performance of buildings using PCMs both with and without air-conditioning is reviewed. Since the particular interest in using PCMs for free cooling and peak load shifting, specific research efforts on both subjects are reviewed separately. A simplified physical dynamic model of building structures integrated with SSPCM (shaped-stabilized phase change material) is developed and validated in this study. The simplified physical model represents the wall by 3 resistances and 2 capacitances and the PCM layer by 4 resistances and 2 capacitances respectively while the key issue is the parameter identification of the model. This thesis also presents the studies on the thermodynamic characteristics of buildings enhanced by PCM and on the investigation of the impacts of PCM on the building cooling load and peak cooling demand at different climates and seasons as well as the optimal operation and control strategies to reduce the energy consumption and energy cost by reducing the air-conditioning energy consumption and peak load. An office building floor with typical variable air volume (VAV) air-conditioning system is used and simulated as the reference building in the comparison study. The envelopes of the studied building are further enhanced by integrating the PCM layers. The building system is tested in two selected cities of typical climates in China including Hong Kong and Beijing. The cold charge and discharge processes, the operation and control strategies of night ventilation and the air temperature set-point reset strategy for minimizing the energy consumption and electricity cost are studied. This thesis presents the simulation test platform, the test results on the cold storage and discharge processes, the air-conditioning energy consumption and demand reduction potentials in typical air-conditioning seasons in typical China cites as well as the impacts of operation and control strategies.

Design of a receiver operating characteristic (ROC) study of 10:1 lossy image compression

NASA Astrophysics Data System (ADS)

Collins, Cary A.; Lane, David; Frank, Mark S.; Hardy, Michael E.; Haynor, David R.; Smith, Donald V.; Parker, James E.; Bender, Gregory N.; Kim, Yongmin

1994-04-01

The digital archiving system at Madigan Army Medical Center (MAMC) uses a 10:1 lossy data compression algorithm for most forms of computed radiography. A systematic study on the potential effect of lossy image compression on patient care has been initiated with a series of studies focused on specific diagnostic tasks. The studies are based upon the receiver operating characteristic (ROC) method of analysis for diagnostic systems. The null hypothesis is that observer performance with approximately 10:1 compressed and decompressed images is not different from using original, uncompressed images for detecting subtle pathologic findings seen on computed radiographs of bone, chest, or abdomen, when viewed on a high-resolution monitor. Our design involves collecting cases from eight pathologic categories. Truth is determined by committee using confirmatory studies performed during routine clinical practice whenever possible. Software has been developed to aid in case collection and to allow reading of the cases for the study using stand-alone Siemens Litebox workstations. Data analysis uses two methods, ROC analysis and free-response ROC (FROC) methods. This study will be one of the largest ROC/FROC studies of its kind and could benefit clinical radiology practice using PACS technology. The study design and results from a pilot FROC study are presented.

Evaluation and Analysis of the ANSI X3T9.5 (FDDI) PMD and Proposed SMF-PMD as Influenced by Various Fiber Link Characteristics

NASA Technical Reports Server (NTRS)

Wernicki, M. Chris

1991-01-01

The purpose of this project is to evaluate the operational parameters of the Kennedy Space Center (KSC) fiber optic cable plant. The evaluation is based on the Fiber Distributed Data Interface (FDDI) Physical Medium Dependent (PMD) and Single Mode Fiber (SMF) PMD standards. From the KSC fiber profile, it would be necessary to develop the modifications needed in existing FDDI PMD and proposed SMF-PMD standards to provide for FDDI implementation and operation at KSC. This analysis should examine the major factors that influence the operating conditions of the KSC fiber plant. These factors would include, but are not limited to the number and type of connectors, attenuation and dispersion characteristics of the fiber, non-standard fiber sizes, modal bandwidth, and many other relevant or significant fiber plant characteristics that effect FDDI characteristics. This analysis is needed to gain a better understanding of overall impact that each of these factors have on FDDI performance at KSC.

Self-injurious behaviour in people with intellectual disability and autism spectrum disorder.

PubMed

Oliver, Chris; Licence, Lucy; Richards, Caroline

2017-03-01

This review summarises the recent trends in research in the field of self-injurious behaviour in people with intellectual disability and autism spectrum disorder. New data on incidence, persistence and severity add to studies of prevalence to indicate the large scale of the clinical need. A number of person characteristics have been repeatedly identified in prevalence and cohort studies that: can be considered as risk markers (e.g. stereotyped behaviour, autism spectrum disorder) and indicate possible causal mechanisms (e.g. sleep disorder, anxiety). Studies have started to integrate traditional operant learning paradigms with known person characteristics and reviews and meta-analyses of applied behaviour analytic procedures can now inform practice. Despite these positive developments interventions and appropriate support falls far short of the required need. Expansions in applied research are warranted to develop and evaluate innovative service delivery models that can translate knowledge of risk markers and operant learning paradigms into widespread, low cost routine clinical practice. Alongside this, further pure research is needed to elucidate the direction of causality of implicated risk factors, in order to understand and intervene more effectively in self-injury.

Predictors of shoulder dystocia at the time of operative vaginal delivery.

PubMed

Palatnik, Anna; Grobman, William A; Hellendag, Madeline G; Janetos, Timothy M; Gossett, Dana R; Miller, Emily S

2016-11-01

It remains uncertain whether clinical factors known prior to delivery can predict which women are more likely to experience shoulder dystocia in the setting of operative vaginal delivery. We sought to identify whether shoulder dystocia can be accurately predicted among women undergoing an operative vaginal delivery. This was a case-control study of women undergoing a low or outlet operative vaginal delivery from 2005 through 2014 in a single tertiary care center. Cases were defined as women who experienced a shoulder dystocia at the time of operative vaginal delivery. Controls consisted of women without a shoulder dystocia at the time of operative vaginal delivery. Variables previously identified to be associated with shoulder dystocia that could be known prior to delivery were abstracted from the medical records. Bivariable analyses and multivariable logistic regression were used to identify factors independently associated with shoulder dystocia. A receiver operating characteristic curve was created to evaluate the predictive value of the model for shoulder dystocia. Of the 4080 women who met inclusion criteria, shoulder dystocia occurred in 162 (4.0%) women. In bivariable analysis, maternal age, parity, body mass index, diabetes, chorioamnionitis, arrest disorder as an indication for an operative vaginal delivery, vacuum use, and estimated fetal weight >4 kg were significantly associated with shoulder dystocia. In multivariable analysis, parity, diabetes, chorioamnionitis, arrest disorder as an indication for operative vaginal delivery, vacuum use, and estimated fetal weight >4 kg remained independently associated with shoulder dystocia. The area under the curve for the generated receiver operating characteristic curve was 0.73 (95% confidence interval, 0.69-0.77), demonstrating only a modest ability to predict shoulder dystocia before performing an operative vaginal delivery. While risk factors for shoulder dystocia at the time of operative vaginal delivery can be identified, reliable prediction of shoulder dystocia in this setting cannot be attained. Copyright © 2016 Elsevier Inc. All rights reserved.

A Pilot Study Investigating Employee Utilization of Corporate Telehealth Services

PubMed Central

Edgerton, Seena Shazowee

2017-01-01

In line with the vision of the University of Mississippi Medical Center (UMMC) to improve health outcomes and eliminate healthcare disparities in Mississippi, a corporate telehealth program was initiated beginning May 2014. A descriptive study was performed to discover common characteristics among enrolled employee users who took advantage of UMMC's corporate telehealth services offered in their workplace throughout the program's first year of operation. This pilot study examined the number of videoconference visits (e-visits) throughout the first year of operation, from May 2014 through April 2015. This examination of common user traits may help identify characteristics that indicate an employee's likelihood of using corporate telehealth. The study revealed the highest use among employees between the ages of 30 and 49 years and among those who attended a formal orientation session including both the employer's human resources personnel and a UMMC corporate telehealth representative. Corporations may find that offering corporate telehealth serves as an effective means to reduce overall healthcare costs and productivity loss. Furthermore, the identification of common variables in this study may help the UMMC corporate telehealth program develop additional methods to reach and assist employees who may not otherwise seek medical treatment. PMID:29118684

Nature and Nurturing: Parenting in the Context of Child Temperament

PubMed Central

Kiff, Cara J.; Lengua, Liliana J.; Zalewski, Maureen

2011-01-01

Accounting for both bidirectional and interactive effects between parenting and child temperament can fine-tune theoretical models of the role of parenting and temperament in children's development of adjustment problems. Evidence for bidirectional and interactive effects between parenting and children's characteristics of frustration, fear, self-regulation, and impulsivity was reviewed, and an overall model of children's individual differences in response to parenting is proposed. In general, children high in frustration, impulsivity and low in effortful control are more vulnerable to the adverse effects of negative parenting, while in turn, many negative parenting behaviors predict increases in these characteristics. Frustration, fearfulness, and effortful control also appear to elicit parenting behaviors that can predict increases in these characteristics. Irritability renders children more susceptible to negative parenting behaviors. Fearfulness operates in a very complex manner, sometimes increasing children's responses to parenting behaviors and sometimes mitigating them and apparently operating differently across gender. Important directions for future research include the use of study designs and analytic approaches that account for the direction of effects and for developmental changes in parenting and temperament over time. PMID:21461681

Operational results for the experimental DOE/NASA Mod-OA wind turbine project

NASA Astrophysics Data System (ADS)

Shaltens, R. K.; Birchenough, A. G.

The Mod-OA wind turbine project which was to gain early experience in the operation of large wind turbines in a utility environment is discussed. The Mod-OA wind turbines were a first generation design, and even though not cost effective, the operating experience and performance characteristics had a significant effect on the design and development of the second and third generation machines. The Mod-OA machines were modified as a result of the operational experience, particularly the blade development and control system strategy. The results of study to investigate the interaction of a Mod-OA wind turbine with an isolated diesel generation system are discussed. The machine configuration, its advantages and disadvantages and the machine performance and availability are discussed.

Operational results for the experimental DOE/NASA Mod-OA wind turbine project

NASA Technical Reports Server (NTRS)

Shaltens, R. K.; Birchenough, A. G.

1983-01-01

The Mod-OA wind turbine project which was to gain early experience in the operation of large wind turbines in a utility environment is discussed. The Mod-OA wind turbines were a first generation design, and even though not cost effective, the operating experience and performance characteristics had a significant effect on the design and development of the second and third generation machines. The Mod-OA machines were modified as a result of the operational experience, particularly the blade development and control system strategy. The results of study to investigate the interaction of a Mod-OA wind turbine with an isolated diesel generation system are discussed. The machine configuration, its advantages and disadvantages and the machine performance and availability are discussed.

Synchronous motor with soft start element formed between the motor rotor and motor output shaft to successfully synchronize loads that have high inertia and/or high torque

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

Umans, Stephen D; Nisley, Donald L; Melfi, Michael J

A line-start synchronous motor has a housing, a rotor shaft, and an output shaft. A soft-start coupling portion is operatively coupled to the output shaft and the rotor shaft. The soft-start coupling portion is configurable to enable the synchronous motor to obtain synchronous operation and to drive, at least near synchronous speed during normal steady state operation of the motor, a load having characteristics sufficient to prevent obtaining normal synchronous operation of the motor when the motor is operatively connected to the load in the absence of the soft-start coupling. The synchronous motor is sufficiently rated to obtain synchronous operationmore » and to drive, at least near synchronous speed during normal steady state operation of the motor, a load having characteristics sufficient to prevent obtaining normal synchronous operation of the motor when the motor is operatively connected to the load in the absence of the soft-start coupling.« less

Research on the Error Characteristics of a 110 kV Optical Voltage Transformer under Three Conditions: In the Laboratory, Off-Line in the Field and During On-Line Operation

PubMed Central

Xiao, Xia; Hu, Haoliang; Xu, Yan; Lei, Min; Xiong, Qianzhu

2016-01-01

Optical voltage transformers (OVTs) have been applied in power systems. When performing accuracy performance tests of OVTs large differences exist between the electromagnetic environment and the temperature variation in the laboratory and on-site. Therefore, OVTs may display different error characteristics under different conditions. In this paper, OVT prototypes with typical structures were selected to be tested for the error characteristics with the same testing equipment and testing method. The basic accuracy, the additional error caused by temperature and the adjacent phase in the laboratory, the accuracy in the field off-line, and the real-time monitoring error during on-line operation were tested. The error characteristics under the three conditions—laboratory, in the field off-line and during on-site operation—were compared and analyzed. The results showed that the effect of the transportation process, electromagnetic environment and the adjacent phase on the accuracy of OVTs could be ignored for level 0.2, but the error characteristics of OVTs are dependent on the environmental temperature and are sensitive to the temperature gradient. The temperature characteristics during on-line operation were significantly superior to those observed in the laboratory. PMID:27537895

Final report on evaluation of cyclocraft support of oil and gas operations in wetland areas

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

Eggington, W.J.; Stevens, P.M.; John, C.J.

1994-10-01

The cyclocraft is a proven hybrid aircraft, capable of VTOL, lifting heavy and bulky loads, highly controllable, having high safety characteristics and low operating costs. Mission Research Corporation (MRC), under Department of Energy sponsorship, is evaluating the potential use of cyclocraft in the transport of drill rigs, mud, pipes and other materials and equipment, in a cost effective and environmentally safe manner, to support oil and gas drilling, production, and transportation operations in wetland areas. Based upon the results of an earlier parametric study, a cyclocraft design, having a payload capacity of 45 tons and designated H.1 Cyclocraft, was selectedmore » for further study, including the preparation of a preliminary design and a development plan, and the determination of operating costs. This report contains all of the results derived from the program to evaluate the use of cyclocraft in the support of oil and gas drilling and production operations in wetland areas.« less

2016 Highlights of Ferry Operations in the United States

DOT National Transportation Integrated Search

2017-10-01

This publication highlights data collected by the 2016 NCFO. The Bureau of Transportation Statistics (BTS) conducted the NCFO from April through November 2016, collecting the operational characteristics of the 2015 calendar year ferry operations.

Wind and turbine characteristics needed for integration of wind turbine arrays into a utility system

NASA Technical Reports Server (NTRS)

Park, G. L.

1982-01-01

Wind data and wind turbine generator (WTG) performance characteristics are often available in a form inconvenient for use by utility planners and engineers. The steps used by utility planners are summarized and the type of wind and WTG data needed for integration of WTG arrays suggested. These included long term yearly velocity averages for preliminary site feasibility, hourly velocities on a 'wind season' basis for more detailed economic analysis and for reliability studies, worst-case velocity profiles for gusts, and various minute-to-hourly velocity profiles for estimating the effect of longer-term wind fluctuations on utility operations. wind turbine data needed includes electrical properties of the generator, startup and shutdown characteristics, protection characteristics, pitch control response and control strategy, and electro-mechanical model for stability analysis.

The Impact of Housing on the Characteristics of Ceramic Pressure Sensors—An Issue of Design for Manufacturability

PubMed Central

Santo Zarnik, Marina; Belavic, Darko; Novak, Franc

2015-01-01

An exploratory study of the impact of housing on the characteristics of a low-temperature co-fired ceramic (LTCC) pressure sensor is presented. The ceramic sensor structure is sealed in a plastic housing. This may have non-negligible effect on the final characteristics and should be considered in the early design phase. The manufacturability issue mainly concerning the selection of available housing and the most appropriate materials was considered with respect to different requirements for low and high pressure ranges of operation. Numerical predictions showed the trends and helped reveal the critical design parameters. Proper selection of the adhesive material remains an essential issue. Curing of the epoxy adhesive may introduce non-negligible residual stresses, which considerably influence the sensor’s characteristics. PMID:26694386

Piloting considerations for terminal area operations of civil tiltwing and tiltrotor aircraft

NASA Technical Reports Server (NTRS)

Hindson, William S.; Hardy, Gordon H.; Tucker, George E.; Decker, William A.

1993-01-01

The existing body of research to investigate airworthiness, performance, handling, and operational requirements for STOL and V/STOL aircraft was reviewed for its applicability to the tiltrotor and tiltwing design concepts. The objective of this study was to help determine the needs for developing civil certification criteria for these aircraft concepts. Piloting tasks that were considered included configuration and thrust vector management, glidepath control, deceleration to hover, and engine failure procedures. Flight control and cockpit display systems that have been found necessary to exploit the low-speed operating characteristics of these aircraft are described, and beneficial future developments are proposed.