Specialized data analysis of SSME and advanced propulsion system vibration measurements

NASA Technical Reports Server (NTRS)

Coffin, Thomas; Swanson, Wayne L.; Jong, Yen-Yi

1993-01-01

The basic objectives of this contract were to perform detailed analysis and evaluation of dynamic data obtained during Space Shuttle Main Engine (SSME) test and flight operations, including analytical/statistical assessment of component dynamic performance, and to continue the development and implementation of analytical/statistical models to effectively define nominal component dynamic characteristics, detect anomalous behavior, and assess machinery operational conditions. This study was to provide timely assessment of engine component operational status, identify probable causes of malfunction, and define feasible engineering solutions. The work was performed under three broad tasks: (1) Analysis, Evaluation, and Documentation of SSME Dynamic Test Results; (2) Data Base and Analytical Model Development and Application; and (3) Development and Application of Vibration Signature Analysis Techniques.

Application of multiplex arrays for cytokine and chemokine profiling of bile.

PubMed

Kemp, Troy J; Castro, Felipe A; Gao, Yu-Tang; Hildesheim, Allan; Nogueira, Leticia; Wang, Bing-Sheng; Sun, Lu; Shelton, Gloriana; Pfeiffer, Ruth M; Hsing, Ann W; Pinto, Ligia A; Koshiol, Jill

2015-05-01

Gallbladder disease is highly related to inflammation, but the inflammatory processes are not well understood. Bile provides a direct substrate in assessing the local inflammatory response that develops in the gallbladder. To assess the reproducibility of measuring inflammatory markers in bile, we designed a methods study of 69 multiplexed immune-related markers measured in bile obtained from gallstone patients. To evaluate assay performance, a total of 18 bile samples were tested twice within the same plate for each analyte, and the 18 bile samples were tested on two different days for each analyte. We used the following performance parameters: detectability, coefficient of variation (CV), intraclass correlation coefficient (ICC), and percent agreement (concordance among replicate measures above and below detection limit). Furthermore, we examined the association of analyte levels with gallstone characteristics such as type, numbers, and size. All but 3 analytes (Stem Cell Factor, SCF; Thrombopoietin, TPO; sIL-1RI) were detectable in bile. 52 of 69 (75.4%) analytes had detectable levels for at least 50% of the subjects tested. The within-plate CVs were ⩽25% for 53 of 66 (80.3%) detectable analytes, and across-plate CVs were ⩽25% for 32 of 66 (48.5%) detectable analytes. Moreover, 64 of 66 (97.0%) analytes had ICC values of at least 0.8. Lastly, the percent agreement was high between replicates for all of the analytes (median; within plate, 97.2%; across plate, 97.2%). In exploratory analyses, we assessed analyte levels by gallstone characteristics and found that levels for several analytes decreased with increasing size of the largest gallstone per patient. Our data suggest that multiplex assays can be used to reliably measure cytokines and chemokines in bile. In addition, gallstone size was inversely related to the levels of select analytes, which may aid in identifying critical pathways and mechanisms associated with the pathogenesis of gallbladder diseases. Copyright © 2015 Elsevier Ltd. All rights reserved.

Knowledge Style Profiling: An Exploration of Cognitive, Temperament, Demographic and Organizational Characteristics among Decision Makers Using Advanced Analytical Technologies

ERIC Educational Resources Information Center

Polito, Vincent A., Jr.

2010-01-01

The objective of this research was to explore the possibilities of identifying knowledge style factors that could be used as central elements of a professional business analyst's (PBA) performance attributes at work for those decision makers that use advanced analytical technologies on decision making tasks. Indicators of knowledge style were…

Correlation and evaluation of inplane stability characteristics for an advanced bearingless main rotor

NASA Technical Reports Server (NTRS)

Weller, W. H.

1983-01-01

A program of experimental and analytical research was performed to demonstrate the degree of correlation achieved between measured and computed rotor inplane stability characteristics. The experimental data were obtained from hover and wind tunnel tests of a scaled bearingless main rotor model. Both isolated rotor and free-hub conditions were tested. Test parameters included blade built-in cone and sweep angles; rotor inplane structural stiffness and damping; pitch link stiffness and location; and fuselage damping, inertia, and natural frequency. Analytical results for many test conditions were obtained. In addition, the analytical and experimental results were examined to ascertain the effects of the test parameters on rotor ground and air resonance stability. The results from this program are presented herein in tabular and graphical form.

An Analytical Design Method for a Regenerative Braking Control System for DC-electrified Railway Systems under Light Load Conditions

NASA Astrophysics Data System (ADS)

Saito, Tatsuhito; Kondo, Keiichiro; Koseki, Takafumi

A DC-electrified railway system that is fed by diode rectifiers at a substation is unable to return the electric power to an AC grid. Accordingly, the braking cars have to restrict regenerative braking power when the power consumption of the powering cars is not sufficient. However, the characteristics of a DC-electrified railway system, including the powering cars, is not known, and a mathematical model for designing a controller has not been established yet. Hence, the object of this study is to obtain the mathematical model for an analytical design method of the regenerative braking control system. In the first part of this paper, the static characteristics of this system are presented to show the position of the equilibrium point. The linearization of this system at the equilibrium point is then performed to describe the dynamic characteristics of the system. An analytical design method is then proposed on the basis of these characteristics. The proposed design method is verified by experimental tests with a 1kW class miniature model, and numerical simulations.

Development and validation of a multi-analyte method for the regulatory control of carotenoids used as feed additives in fish and poultry feed.

PubMed

Vincent, Ursula; Serano, Federica; von Holst, Christoph

2017-08-01

Carotenoids are used in animal nutrition mainly as sensory additives that favourably affect the colour of fish, birds and food of animal origin. Various analytical methods exist for their quantification in compound feed, reflecting the different physico-chemical characteristics of the carotenoid and the corresponding feed additives. They may be natural products or specific formulations containing the target carotenoids produced by chemical synthesis. In this study a multi-analyte method was developed that can be applied to the determination of all 10 carotenoids currently authorised within the European Union for compound feedingstuffs. The method functions regardless of whether the carotenoids have been added to the compound feed via natural products or specific formulations. It is comprised of three steps: (1) digestion of the feed sample with an enzyme; (2) pressurised liquid extraction; and (3) quantification of the analytes by reversed-phase HPLC coupled to a photodiode array detector in the visible range. The method was single-laboratory validated for poultry and fish feed covering a mass fraction range of the target analyte from 2.5 to 300 mg kg - 1 . The following method performance characteristics were obtained: the recovery rate varied from 82% to 129% and precision expressed as the relative standard deviation of intermediate precision varied from 1.6% to 15%. Based on the acceptable performance obtained in the validation study, the multi-analyte method is considered fit for the intended purpose.

Analytical Performance Characteristics of the Cepheid GeneXpert Ebola Assay for the Detection of Ebola Virus

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

Pinsky, Benjamin A.; Sahoo, Malaya K.; Sandlund, Johanna

The recently developed Xpert® Ebola Assay is a novel nucleic acid amplification test for simplified detection of Ebola virus (EBOV) in whole blood and buccal swab samples. The assay targets sequences in two EBOV genes, lowering the risk for new variants to escape detection in the test. The objective of this report is to present analytical characteristics of the Xpert® Ebola Assay on whole blood samples. Our study evaluated the assay’s analytical sensitivity, analytical specificity, inclusivity and exclusivity performance in whole blood specimens. EBOV RNA, inactivated EBOV, and infectious EBOV were used as targets. The dynamic range of the assay,more » the inactivation of virus, and specimen stability were also evaluated. The lower limit of detection (LoD) for the assay using inactivated virus was estimated to be 73 copies/mL (95% CI: 51–97 copies/mL). The LoD for infectious virus was estimated to be 1 plaque-forming unit/mL, and for RNA to be 232 copies/mL (95% CI 163–302 copies/mL). The assay correctly identified five different Ebola viruses, Yambuku-Mayinga, Makona-C07, Yambuku-Ecran, Gabon-Ilembe, and Kikwit-956210, and correctly excluded all non-EBOV isolates tested. The conditions used by Xpert® Ebola for inactivation of infectious virus reduced EBOV titer by ≥6 logs. In conclusion, we found the Xpert® Ebola Assay to have high analytical sensitivity and specificity for the detection of EBOV in whole blood. It offers ease of use, fast turnaround time, and remote monitoring. The test has an efficient viral inactivation protocol, fulfills inclusivity and exclusivity criteria, and has specimen stability characteristics consistent with the need for decentralized testing. The simplicity of the assay should enable testing in a wide variety of laboratory settings, including remote laboratories that are not capable of performing highly complex nucleic acid amplification tests, and during outbreaks where time to detection is critical.« less

Analytical Performance Characteristics of the Cepheid GeneXpert Ebola Assay for the Detection of Ebola Virus

DOE PAGES

Pinsky, Benjamin A.; Sahoo, Malaya K.; Sandlund, Johanna; ...

2015-11-12

The recently developed Xpert® Ebola Assay is a novel nucleic acid amplification test for simplified detection of Ebola virus (EBOV) in whole blood and buccal swab samples. The assay targets sequences in two EBOV genes, lowering the risk for new variants to escape detection in the test. The objective of this report is to present analytical characteristics of the Xpert® Ebola Assay on whole blood samples. Our study evaluated the assay’s analytical sensitivity, analytical specificity, inclusivity and exclusivity performance in whole blood specimens. EBOV RNA, inactivated EBOV, and infectious EBOV were used as targets. The dynamic range of the assay,more » the inactivation of virus, and specimen stability were also evaluated. The lower limit of detection (LoD) for the assay using inactivated virus was estimated to be 73 copies/mL (95% CI: 51–97 copies/mL). The LoD for infectious virus was estimated to be 1 plaque-forming unit/mL, and for RNA to be 232 copies/mL (95% CI 163–302 copies/mL). The assay correctly identified five different Ebola viruses, Yambuku-Mayinga, Makona-C07, Yambuku-Ecran, Gabon-Ilembe, and Kikwit-956210, and correctly excluded all non-EBOV isolates tested. The conditions used by Xpert® Ebola for inactivation of infectious virus reduced EBOV titer by ≥6 logs. In conclusion, we found the Xpert® Ebola Assay to have high analytical sensitivity and specificity for the detection of EBOV in whole blood. It offers ease of use, fast turnaround time, and remote monitoring. The test has an efficient viral inactivation protocol, fulfills inclusivity and exclusivity criteria, and has specimen stability characteristics consistent with the need for decentralized testing. The simplicity of the assay should enable testing in a wide variety of laboratory settings, including remote laboratories that are not capable of performing highly complex nucleic acid amplification tests, and during outbreaks where time to detection is critical.« less

The Use and Abuse of Limits of Detection in Environmental Analytical Chemistry

PubMed Central

Brown, Richard J. C.

2008-01-01

The limit of detection (LoD) serves as an important method performance measure that is useful for the comparison of measurement techniques and the assessment of likely signal to noise performance, especially in environmental analytical chemistry. However, the LoD is only truly related to the precision characteristics of the analytical instrument employed for the analysis and the content of analyte in the blank sample. This article discusses how other criteria, such as sampling volume, can serve to distort the quoted LoD artificially and make comparison between various analytical methods inequitable. In order to compare LoDs between methods properly, it is necessary to state clearly all of the input parameters relating to the measurements that have been used in the calculation of the LoD. Additionally, the article discusses that the use of LoDs in contexts other than the comparison of the attributes of analytical methods, in particular when reporting analytical results, may be confusing, less informative than quoting the actual result with an accompanying statement of uncertainty, and may act to bias descriptive statistics. PMID:18690384

A semi-analytical refrigeration cycle modelling approach for a heat pump hot water heater

NASA Astrophysics Data System (ADS)

Panaras, G.; Mathioulakis, E.; Belessiotis, V.

2018-04-01

The use of heat pump systems in applications like the production of hot water or space heating makes important the modelling of the processes for the evaluation of the performance of existing systems, as well as for design purposes. The proposed semi-analytical model offers the opportunity to estimate the performance of a heat pump system producing hot water, without using detailed geometrical or any performance data. This is important, as for many commercial systems the type and characteristics of the involved subcomponents can hardly be detected, thus not allowing the implementation of more analytical approaches or the exploitation of the manufacturers' catalogue performance data. The analysis copes with the issues related with the development of the models of the subcomponents involved in the studied system. Issues not discussed thoroughly in the existing literature, as the refrigerant mass inventory in the case an accumulator is present, are examined effectively.

Experimental and analytical studies for the NASA carbon fiber risk assessment

NASA Technical Reports Server (NTRS)

1980-01-01

Various experimental and analytical studies performed for the NASA carbon fiber risk assessment program are described with emphasis on carbon fiber characteristics, sensitivity of electrical equipment and components to shorting or arcing by carbon fibers, attenuation effect of carbon fibers on aircraft landing aids, impact of carbon fibers on industrial facilities. A simple method of estimating damage from airborne carbon fibers is presented.

Analytical performance specifications for changes in assay bias (Δbias) for data with logarithmic distributions as assessed by effects on reference change values.

PubMed

Petersen, Per H; Lund, Flemming; Fraser, Callum G; Sölétormos, György

2016-11-01

Background The distributions of within-subject biological variation are usually described as coefficients of variation, as are analytical performance specifications for bias, imprecision and other characteristics. Estimation of specifications required for reference change values is traditionally done using relationship between the batch-related changes during routine performance, described as Δbias, and the coefficients of variation for analytical imprecision (CV A ): the original theory is based on standard deviations or coefficients of variation calculated as if distributions were Gaussian. Methods The distribution of between-subject biological variation can generally be described as log-Gaussian. Moreover, recent analyses of within-subject biological variation suggest that many measurands have log-Gaussian distributions. In consequence, we generated a model for the estimation of analytical performance specifications for reference change value, with combination of Δbias and CV A based on log-Gaussian distributions of CV I as natural logarithms. The model was tested using plasma prolactin and glucose as examples. Results Analytical performance specifications for reference change value generated using the new model based on log-Gaussian distributions were practically identical with the traditional model based on Gaussian distributions. Conclusion The traditional and simple to apply model used to generate analytical performance specifications for reference change value, based on the use of coefficients of variation and assuming Gaussian distributions for both CV I and CV A , is generally useful.

Piezocone Penetration Testing Device

DOT National Transportation Integrated Search

2017-01-03

Hydraulic characteristics of soils can be estimated from piezocone penetration test (called PCPT hereinafter) by performing dissipation test or on-the-fly using advanced analytical techniques. This research report presents a method for fast estimatio...

Technical, analytical and computer support

NASA Technical Reports Server (NTRS)

1972-01-01

The development of a rigorous mathematical model for the design and performance analysis of cylindrical silicon-germanium thermoelectric generators is reported that consists of two parts, a steady-state (static) and a transient (dynamic) part. The material study task involves the definition and implementation of a material study that aims to experimentally characterize the long term behavior of the thermoelectric properties of silicon-germanium alloys as a function of temperature. Analytical and experimental efforts are aimed at the determination of the sublimation characteristics of silicon germanium alloys and the study of sublimation effects on RTG performance. Studies are also performed on a variety of specific topics on thermoelectric energy conversion.

Retardation analytical model to extend service life

NASA Technical Reports Server (NTRS)

Matejczyk, D.

1984-01-01

A fatigue crack growth model that incorporates crack growth retardation effects and is applicable to the materials characteristics and service environments of high performance LH2/LO2 engine systems was developed and tested.

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.

TRAC performance estimates

NASA Technical Reports Server (NTRS)

Everett, L.

1992-01-01

This report documents the performance characteristics of a Targeting Reflective Alignment Concept (TRAC) sensor. The performance will be documented for both short and long ranges. For long ranges, the sensor is used without the flat mirror attached to the target. To better understand the capabilities of the TRAC based sensors, an engineering model is required. The model can be used to better design the system for a particular application. This is necessary because there are many interrelated design variables in application. These include lense parameters, camera, and target configuration. The report presents first an analytical development of the performance, and second an experimental verification of the equations. In the analytical presentation it is assumed that the best vision resolution is a single pixel element. The experimental results suggest however that the resolution is better than 1 pixel. Hence the analytical results should be considered worst case conditions. The report also discusses advantages and limitations of the TRAC sensor in light of the performance estimates. Finally the report discusses potential improvements.

Investigating the Mobility of Trilayer Graphene Nanoribbon in Nanoscale FETs

NASA Astrophysics Data System (ADS)

Rahmani, Meisam; Ghafoori Fard, Hassan; Ahmadi, Mohammad Taghi; Rahbarpour, Saeideh; Habibiyan, Hamidreza; Varmazyari, Vali; Rahmani, Komeil

2017-10-01

The aim of the present paper is to investigate the scaling behaviors of charge carrier mobility as one of the most remarkable characteristics for modeling of nanoscale field-effect transistors (FETs). Many research groups in academia and industry are contributing to the model development and experimental identification of multi-layer graphene FET-based devices. The approach in the present work is to provide an analytical model for carrier mobility of tri-layer graphene nanoribbon (TGN) FET. In order to do so, one starts by identifying the analytical modeling of TGN carrier velocity and ballistic conductance. At the end, a model of charge carrier mobility with numerical solution is analytically derived for TGN FET, in which the carrier concentration, temperature and channel length characteristics dependence are highlighted. Moreover, variation of band gap and gate voltage during the proposed device operation and its effect on carrier mobility is investigated. To evaluate the nanoscale FET performance, the carrier mobility model is also adopted to obtain the I-V characteristics of the device. In order to verify the accuracy of the proposed analytical model for TGN mobility, it is compared to the existing experimental data, and a satisfactory agreement is reported for analogous ambient conditions. Moreover, the proposed model is compared with the published data of single-layer graphene and bi-layer graphene, in which the obtained results demonstrate significant insights into the importance of charge carrier mobility impact in high-performance TGN FET. The work presented here is one step towards an applicable model for real-world nanoscale FETs.

Development Of Antibody-Based Fiber-Optic Sensors

NASA Astrophysics Data System (ADS)

Tromberg, Bruce J.; Sepaniak, Michael J.; Vo-Dinh, Tuan

1988-06-01

The speed and specificity characteristic of immunochemical complex formation has encouraged the development of numerous antibody-based analytical techniques. The scope and versatility of these established methods can be enhanced by combining the principles of conventional immunoassay with laser-based fiber-optic fluorimetry. This merger of spectroscopy and immunochemistry provides the framework for the construction of highly sensitive and selective fiber-optic devices (fluoroimmuno-sensors) capable of in-situ detection of drugs, toxins, and naturally occurring biochemicals. Fluoroimmuno-sensors (FIS) employ an immobilized reagent phase at the sampling terminus of a single quartz optical fiber. Laser excitation of antibody-bound analyte produces a fluorescence signal which is either directly proportional (as in the case of natural fluorophor and "antibody sandwich" assays) or inversely proportional (as in the case of competitive-binding assays) to analyte concentration. Factors which influence analysis time, precision, linearity, and detection limits include the nature (solid or liquid) and amount of the reagent phase, the method of analyte delivery (passive diffusion, convection, etc.), and whether equilibrium or non-equilibrium assays are performed. Data will be presented for optical fibers whose sensing termini utilize: (1) covalently-bound solid antibody reagent phases, and (2) membrane-entrapped liquid antibody reagents. Assays for large-molecular weight proteins (antigens) and small-molecular weight, carcinogenic, polynuclear aromatics (haptens) will be considered. In this manner, the influence of a system's chemical characteristics and measurement requirements on sensor design, and the consequence of various sensor designs on analytical performance will be illustrated.

Experimental Validation of the Transverse Shear Behavior of a Nomex Core for Sandwich Panels

NASA Astrophysics Data System (ADS)

Farooqi, M. I.; Nasir, M. A.; Ali, H. M.; Ali, Y.

2017-05-01

This work deals with determination of the transverse shear moduli of a Nomex® honeycomb core of sandwich panels. Their out-of-plane shear characteristics depend on the transverse shear moduli of the honeycomb core. These moduli were determined experimentally, numerically, and analytically. Numerical simulations were performed by using a unit cell model and three analytical approaches. Analytical calculations showed that two of the approaches provided reasonable predictions for the transverse shear modulus as compared with experimental results. However, the approach based upon the classical lamination theory showed large deviations from experimental data. Numerical simulations also showed a trend similar to that resulting from the analytical models.

Multi-center evaluation of analytical performance of the Beckman Coulter AU5822 chemistry analyzer.

PubMed

Zimmerman, M K; Friesen, L R; Nice, A; Vollmer, P A; Dockery, E A; Rankin, J D; Zmuda, K; Wong, S H

2015-09-01

Our three academic institutions, Indiana University, Northwestern Memorial Hospital, and Wake Forest, were among the first in the United States to implement the Beckman Coulter AU5822 series chemistry analyzers. We undertook this post-hoc multi-center study by merging our data to determine performance characteristics and the impact of methodology changes on analyte measurement. We independently completed performance validation studies including precision, linearity/analytical measurement range, method comparison, and reference range verification. Complete data sets were available from at least one institution for 66 analytes with the following groups: 51 from all three institutions, and 15 from 1 or 2 institutions for a total sample size of 12,064. Precision was similar among institutions. Coefficients of variation (CV) were <10% for 97%. Analytes with CVs >10% included direct bilirubin and digoxin. All analytes exhibited linearity over the analytical measurement range. Method comparison data showed slopes between 0.900-1.100 for 87.9% of the analytes. Slopes for amylase, tobramycin and urine amylase were <0.8; the slope for lipase was >1.5, due to known methodology or standardization differences. Consequently, reference ranges of amylase, urine amylase and lipase required only minor or no modification. The four AU5822 analyzers independently evaluated at three sites showed consistent precision, linearity, and correlation results. Since installations, the test results had been well received by clinicians from all three institutions. Copyright © 2015. Published by Elsevier Inc.

Besifloxacin: A Critical Review of Its Characteristics, Properties, and Analytical Methods.

PubMed

Tótoli, Eliane Gandolpho; Salgado, Hérida Regina Nunes

2018-03-04

Bacterial conjunctivitis has high impact on the health of the population, since it represents more than a third of ocular pathologies reported by health services worldwide. There is a high incidence of bacterial resistance to the antimicrobials most commonly used for the treatment of conjunctivitis. In this context, besifloxacin stands out, since it is a fluoroquinolone developed exclusively for topical ophthalmic use, presenting a low risk of developing resistance due to its reduced systemic exposure. Bausch & Lomb markets it as ophthalmic suspension, under the trade name Besivance™. Literature review on besifloxacin is presented, covering its pharmaceutical and clinical characteristics, and the analytical methods used to measure the drug in pharmaceutical products and biological samples. High performance liquid chromatography is the most used method for this purpose. A discussion on Green Chemistry is also presented, focusing the importance of the development of green analytical methods for the analysis of drugs.

Retardation analytical model to extend service life

NASA Technical Reports Server (NTRS)

Matejczyk, J.

1984-01-01

A fatigue crack growth model that incorporates crack growth retardation effects and is applicable to the materials characteristics and service environments of high performance LH2/LO2 engine systems is discussed. Future Research plans are outlined.

Analytical Performance Modeling and Validation of Intel’s Xeon Phi Architecture

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

Chunduri, Sudheer; Balaprakash, Prasanna; Morozov, Vitali

Modeling the performance of scientific applications on emerging hardware plays a central role in achieving extreme-scale computing goals. Analytical models that capture the interaction between applications and hardware characteristics are attractive because even a reasonably accurate model can be useful for performance tuning before the hardware is made available. In this paper, we develop a hardware model for Intel’s second-generation Xeon Phi architecture code-named Knights Landing (KNL) for the SKOPE framework. We validate the KNL hardware model by projecting the performance of mini-benchmarks and application kernels. The results show that our KNL model can project the performance with prediction errorsmore » of 10% to 20%. The hardware model also provides informative recommendations for code transformations and tuning.« less

Location of Biomarkers and Reagents within Agarose Beads of a Programmable Bio-nano-chip

PubMed Central

Jokerst, Jesse V.; Chou, Jie; Camp, James P.; Wong, Jorge; Lennart, Alexis; Pollard, Amanda A.; Floriano, Pierre N.; Christodoulides, Nicolaos; Simmons, Glennon W.; Zhou, Yanjie; Ali, Mehnaaz F.

2012-01-01

The slow development of cost-effective medical microdevices with strong analytical performance characteristics is due to a lack of selective and efficient analyte capture and signaling. The recently developed programmable bio-nano-chip (PBNC) is a flexible detection device with analytical behavior rivaling established macroscopic methods. The PBNC system employs ≈300 μm-diameter bead sensors composed of agarose “nanonets” that populate a microelectromechanical support structure with integrated microfluidic elements. The beads are an efficient and selective protein-capture medium suitable for the analysis of complex fluid samples. Microscopy and computational studies probe the 3D interior of the beads. The relative contributions that the capture and detection of moieties, analyte size, and bead porosity make to signal distribution and intensity are reported. Agarose pore sizes ranging from 45 to 620 nm are examined and those near 140 nm provide optimal transport characteristics for rapid (<15 min) tests. The system exhibits efficient (99.5%) detection of bead-bound analyte along with low (≈2%) nonspecific immobilization of the detection probe for carcinoembryonic antigen assay. Furthermore, the role analyte dimensions play in signal distribution is explored, and enhanced methods for assay building that consider the unique features of biomarker size are offered. PMID:21290601

A survey on platforms for big data analytics.

PubMed

Singh, Dilpreet; Reddy, Chandan K

The primary purpose of this paper is to provide an in-depth analysis of different platforms available for performing big data analytics. This paper surveys different hardware platforms available for big data analytics and assesses the advantages and drawbacks of each of these platforms based on various metrics such as scalability, data I/O rate, fault tolerance, real-time processing, data size supported and iterative task support. In addition to the hardware, a detailed description of the software frameworks used within each of these platforms is also discussed along with their strengths and drawbacks. Some of the critical characteristics described here can potentially aid the readers in making an informed decision about the right choice of platforms depending on their computational needs. Using a star ratings table, a rigorous qualitative comparison between different platforms is also discussed for each of the six characteristics that are critical for the algorithms of big data analytics. In order to provide more insights into the effectiveness of each of the platform in the context of big data analytics, specific implementation level details of the widely used k-means clustering algorithm on various platforms are also described in the form pseudocode.

Analytical Performance Characteristics of the Cepheid GeneXpert Ebola Assay for the Detection of Ebola Virus

PubMed Central

Pinsky, Benjamin A.; Sahoo, Malaya K.; Sandlund, Johanna; Kleman, Marika; Kulkarni, Medha; Grufman, Per; Nygren, Malin; Kwiatkowski, Robert; Baron, Ellen Jo; Tenover, Fred; Denison, Blake; Higuchi, Russell; Van Atta, Reuel; Beer, Neil Reginald; Carrillo, Alda Celena; Naraghi-Arani, Pejman; Mire, Chad E.; Ranadheera, Charlene; Grolla, Allen; Lagerqvist, Nina; Persing, David H.

2015-01-01

Background The recently developed Xpert® Ebola Assay is a novel nucleic acid amplification test for simplified detection of Ebola virus (EBOV) in whole blood and buccal swab samples. The assay targets sequences in two EBOV genes, lowering the risk for new variants to escape detection in the test. The objective of this report is to present analytical characteristics of the Xpert® Ebola Assay on whole blood samples. Methods and Findings This study evaluated the assay’s analytical sensitivity, analytical specificity, inclusivity and exclusivity performance in whole blood specimens. EBOV RNA, inactivated EBOV, and infectious EBOV were used as targets. The dynamic range of the assay, the inactivation of virus, and specimen stability were also evaluated. The lower limit of detection (LoD) for the assay using inactivated virus was estimated to be 73 copies/mL (95% CI: 51–97 copies/mL). The LoD for infectious virus was estimated to be 1 plaque-forming unit/mL, and for RNA to be 232 copies/mL (95% CI 163–302 copies/mL). The assay correctly identified five different Ebola viruses, Yambuku-Mayinga, Makona-C07, Yambuku-Ecran, Gabon-Ilembe, and Kikwit-956210, and correctly excluded all non-EBOV isolates tested. The conditions used by Xpert® Ebola for inactivation of infectious virus reduced EBOV titer by ≥6 logs. Conclusion In summary, we found the Xpert® Ebola Assay to have high analytical sensitivity and specificity for the detection of EBOV in whole blood. It offers ease of use, fast turnaround time, and remote monitoring. The test has an efficient viral inactivation protocol, fulfills inclusivity and exclusivity criteria, and has specimen stability characteristics consistent with the need for decentralized testing. The simplicity of the assay should enable testing in a wide variety of laboratory settings, including remote laboratories that are not capable of performing highly complex nucleic acid amplification tests, and during outbreaks where time to detection is critical. PMID:26562786

Study of Spray Disintegration in Accelerating Flow Fields

NASA Technical Reports Server (NTRS)

Nurick, W. H.

1972-01-01

An analytical and experimental investigation was conducted to perform "proof of principlem experiments to establish the effects of propellant combustion gas velocity on propella'nt atomization characteristics. The propellants were gaseous oxygen (GOX) and Shell Wax 270. The fuel was thus the same fluid used in earlier primary cold-flow atomization studies using the frozen wax method. Experiments were conducted over a range in L* (30 to 160 inches) at two contraction ratios (2 and 6). Characteristic exhaust velocity (c*) efficiencies varied from SO to 90 percent. The hot fire experimental performance characteristics at a contraction ratio of 6.0 in conjunction with analytical predictions from the drovlet heat-up version of the Distributed Energy Release (DER) combustion computer proDam showed that the apparent initial dropsize compared well with cold-flow predictions (if adjusted for the gas velocity effects). The results also compared very well with the trend in perfomnce as predicted with the model. significant propellant wall impingement at the contraction ratio of 2.0 precluded complete evaluation of the effect of gross changes in combustion gas velocity on spray dropsize.

Contribution of Electrochemistry to the Biomedical and Pharmaceutical Analytical Sciences.

PubMed

Kauffmann, Jean-Michel; Patris, Stephanie; Vandeput, Marie; Sarakbi, Ahmad; Sakira, Abdul Karim

2016-01-01

All analytical techniques have experienced major progress since the last ten years and electroanalysis is also involved in this trend. The unique characteristics of phenomena occurring at the electrode-solution interface along with the variety of electrochemical methods currently available allow for a broad spectrum of applications. Potentiometric, conductometric, voltammetric and amperometric methods are briefly reviewed with a critical view in terms of performance of the developed instrumentation with special emphasis on pharmaceutical and biomedical applications.

Analytical study of effect of casing treatment on performance of a multistage compressor

NASA Technical Reports Server (NTRS)

Snyder, R. W.; Blade, R. J.

1972-01-01

The simulation was based on individual stage pressure and efficiency maps. These maps were modified to account for casing treatment effects on the individual stage characteristics. The individual stage maps effects on overall compressor performance were observed. The results show that to improve the performance of the compressor in its normal operating range, casing treatment of the rear stages is required.

Advances in organic-inorganic hybrid sorbents for the extraction of organic and inorganic pollutants in different types of food and environmental samples.

PubMed

Ng, Nyuk-Ting; Kamaruddin, Amirah Farhan; Wan Ibrahim, Wan Aini; Sanagi, Mohd Marsin; Abdul Keyon, Aemi S

2018-01-01

The efficiency of the extraction and removal of pollutants from food and the environment has been an important issue in analytical science. By incorporating inorganic species into an organic matrix, a new material known as an organic-inorganic hybrid material is formed. As it possesses high selectivity, permeability, and mechanical and chemical stabilities, organic-inorganic hybrid materials constitute an emerging research field and have become popular to serve as sorbents in various separaton science methods. Here, we review recent significant advances in analytical solid-phase extraction employing organic-inorganic composite/nanocomposite sorbents for the extraction of organic and inorganic pollutants from various types of food and environmental matrices. The physicochemical characteristics, extraction properties, and analytical performances of sorbents are discussed; including morphology and surface characteristics, types of functional groups, interaction mechanism, selectivity and sensitivity, accuracy, and regeneration abilities. Organic-inorganic hybrid sorbents combined with extraction techniques are highly promising for sample preparation of various food and environmental matrixes with analytes at trace levels. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In-orbit evaluation of the control system/structural mode interactions of the OSO-8 spacecraft

NASA Technical Reports Server (NTRS)

Slafer, L. I.

1979-01-01

The Orbiting Solar Observatory-8 experienced severe structural mode/control loop interaction problems during the spacecraft development. Extensive analytical studies, using the hybrid coordinate modeling approach, and comprehensive ground testing were carried out in order to achieve the system's precision pointing performance requirements. A recent series of flight tests were conducted with the spacecraft in which a wide bandwidth, high resolution telemetry system was utilized to evaluate the on-orbit flexible dynamics characteristics of the vehicle along with the control system performance. The paper describes the results of these tests, reviewing the basic design problem, analytical approach taken, ground test philosophy, and on-orbit testing. Data from the tests was used to determine the primary mode frequency, damping, and servo coupling dynamics for the on-orbit condition. Additionally, the test results have verified analytically predicted differences between the on-orbit and ground test environments, and have led to a validation of both the analytical modeling and servo design techniques used during the development of the control system.

Influence of consumers' cognitive style on results from projective mapping.

PubMed

Varela, Paula; Antúnez, Lucía; Berget, Ingunn; Oliveira, Denize; Christensen, Kasper; Vidal, Leticia; Naes, Tormod; Ares, Gastón

2017-09-01

Projective mapping (PM), one of the most holistic product profiling methods in approach, is increasingly being used to uncover consumers' perception of products and packages. Assessors rely on a process of synthesis for evaluating product information, which would determine the relative importance of the perceived characteristics they use for mapping them. Individual differences are expected, as participants are not instructed on the characteristics to consider for evaluating the degree of difference among samples, generating different perceptual spaces. Individual differences in cognitive style can affect synthesis processes and thus their perception of similarities and differences among samples. In this study, the influence of the cognitive style in the results of PM was explored. Two consumer studies were performed, one aimed at describing intrinsic sensory characteristics of chocolate flavoured milk and the other one looking into extrinsic (package only) of blueberry yogurts. Consumers completed the wholistic-analytic module of the extended Verbal Imagery Cognitive Styles Test & Extended Cognitive Style Analysis-Wholistic Analytic Test, to characterize their cognitive style. Differences between wholistic and analytic consumers in how they evaluated samples using projective mapping were found in both studies. Analytics separated the samples more in the PM perceptual space than wholistic consumers, showing more discriminating abilities. This may come from a deeper analysis of the samples, both from intrinsic and extrinsic point of views. From a sensory perspective (intrinsic), analytic consumers relied on more sensory characteristics, while wholistic mainly discriminated samples according to sweetness and bitterness/chocolate flavour. In the extrinsic study however, even if analytic consumers discriminated more between packs, they described the products using similar words in the descriptive step. One important recommendation coming from this study is the need to consider higher dimensions in the interpretation of projective mapping tasks, as the first dimensions could underestimate the complexity of the perceptual space; currently, most applications of PM consider two dimensions only, which may not uncover the perception of specific groups of consumers. Copyright © 2017 Elsevier Ltd. All rights reserved.

Development of a plasma sprayed ceramic gas path seal for high pressure turbine applications

NASA Technical Reports Server (NTRS)

Shiembob, L. T.

1977-01-01

The plasma sprayed graded layered yittria stabilized zirconia (ZrO2)/metal(CoCrAlY) seal system for gas turbine blade tip applications up to 1589 K (2400 F) seal temperatures was studied. Abradability, erosion, and thermal fatigue characteristics of the graded layered system were evaluated by rig tests. Satisfactory abradability and erosion resistance was demonstrated. Encouraging thermal fatigue tolerance was shown. Initial properties for the plasma sprayed materials in the graded, layered seal system was obtained, and thermal stress analyses were performed. Sprayed residual stresses were determined. Thermal stability of the sprayed layer materials was evaluated at estimated maximum operating temperatures in each layer. Anisotropic behavior in the layer thickness direction was demonstrated by all layers. Residual stresses and thermal stability effects were not included in the analyses. Analytical results correlated reasonably well with results of the thermal fatigue tests. Analytical application of the seal system to a typical gas turbine engine application predicted performance similar to rig specimen thermal fatigue performance. A model for predicting crack propagation in the sprayed ZrO2/CoCrAlY seal system was proposed, and recommendations for improving thermal fatigue resistance were made. Seal system layer thicknesses were analytically optimized to minimize thermal stresses in the abradability specimen during thermal fatigue testing. Rig tests on the optimized seal configuration demonstrated some improvement in thermal fatigue characteristics.

Effect of Vibration on Retention Characteristics of Screen Acquisition Systems

NASA Technical Reports Server (NTRS)

Tegart, J. R.; Park, A. C.

1977-01-01

An analytical and experimental investigation of the effect of vibration on the retention characteristics of screen acquisition systems was performed. The functioning of surface tension devices using fine-mesh screens requires that the pressure differential acting on the screen be less than its pressure retention capability. When exceeded, screen breakdown will occur and gas-free expulsion of propellant will no longer be possible. An analytical approach to predicting the effect of vibration was developed. This approach considers the transmission of the vibration to the screens of the device and the coupling of the liquid and the screen in establishing the screen response. A method of evaluating the transient response of the gas/liquid interface within the screen was also developed.

Liquid Oxygen/Liquid Methane Integrated Propulsion System Test Bed

NASA Technical Reports Server (NTRS)

Flynn, Howard; Lusby, Brian; Villemarette, Mark

2011-01-01

In support of NASA?s Propulsion and Cryogenic Advanced Development (PCAD) project, a liquid oxygen (LO2)/liquid methane (LCH4) Integrated Propulsion System Test Bed (IPSTB) was designed and advanced to the Critical Design Review (CDR) stage at the Johnson Space Center. The IPSTB?s primary objectives are to study LO2/LCH4 propulsion system steady state and transient performance, operational characteristics and to validate fluid and thermal models of a LO2/LCH4 propulsion system for use in future flight design work. Two phase thermal and dynamic fluid flow models of the IPSTB were built to predict the system performance characteristics under a variety of operating modes and to aid in the overall system design work. While at ambient temperature and simulated altitude conditions at the White Sands Test Facility, the IPSTB and its approximately 600 channels of system instrumentation would be operated to perform a variety of integrated main engine and reaction control engine hot fire tests. The pressure, temperature, and flow rate data collected during this testing would then be used to validate the analytical models of the IPSTB?s thermal and dynamic fluid flow performance. An overview of the IPSTB design and analytical model development will be presented.

Comparative chromatography-mass spectrometry studies on the antiretroviral drug nevirapine-analytical performance characteristics in human plasma determination.

PubMed

Sichilongo, Kwenga; Chinyama, Mompati; Massele, Amos; Vento, Sandro

2014-01-15

A contrast between the analytical performance characteristics using gas chromatography-mass spectrometry (GC-MS) liquid chromatography-mass spectrometry (LC-MS) and liquid chromatography-ultraviolet (LC-UV) detection for the determination of the antiretroviral drug (ARV) nevirapine (NVP) in fortified human plasma after QuEChERS extraction has been made. Analytical performance characteristics, i.e. linearities, instrument detection limits (IDLs), limits of quantitation (LOQs), method detection limits (MDLs), % mean recoveries and the corresponding relative standard deviations (%RSDs) were estimated using techniques above. Using GC-MS, the correlation coefficients (r(2)) were ≥0.990, which were deemed acceptable linearities. The MDLs ranged between 11.1-29.8μg/L and 13.7-36.0μg/L using helium and hydrogen carrier gases respectively. The LOQs ranged between 16.5-66.7μg/L and 28.4-98.7μg/L using helium and hydrogen carrier gases respectively with a % mean recovery of 83% and %RSD of 4.6%. Using LC-MS and LC-UV, the correlation coefficients (r(2)) were ≥0.990. The MDLs were ranged between 3.14 and 47.1μg/L. The LOQs ranged between 2.85 and 90.0μg/L respectively. The MDLs using GC-MS, LC-MS and LC-UV were below the therapeutic range for NVP in human plasma is considered to be between 2300μg/L (Cmin) and 8000μg/L (Cmax). This study also demonstrated that helium can be substituted with hydrogen which is relatively cheaper and easily obtainable even by use of a generator. Copyright © 2013 Elsevier B.V. All rights reserved.

Rate decline curves analysis of multiple-fractured horizontal wells in heterogeneous reservoirs

NASA Astrophysics Data System (ADS)

Wang, Jiahang; Wang, Xiaodong; Dong, Wenxiu

2017-10-01

In heterogeneous reservoir with multiple-fractured horizontal wells (MFHWs), due to the high density network of artificial hydraulic fractures, the fluid flow around fracture tips behaves like non-linear flow. Moreover, the production behaviors of different artificial hydraulic fractures are also different. A rigorous semi-analytical model for MFHWs in heterogeneous reservoirs is presented by combining source function with boundary element method. The model are first validated by both analytical model and simulation model. Then new Blasingame type curves are established. Finally, the effects of critical parameters on the rate decline characteristics of MFHWs are discussed. The results show that heterogeneity has significant influence on the rate decline characteristics of MFHWs; the parameters related to the MFHWs, such as fracture conductivity and length also can affect the rate characteristics of MFHWs. One novelty of this model is to consider the elliptical flow around artificial hydraulic fracture tips. Therefore, our model can be used to predict rate performance more accurately for MFHWs in heterogeneous reservoir. The other novelty is the ability to model the different production behavior at different fracture stages. Compared to numerical and analytic methods, this model can not only reduce extensive computing processing but also show high accuracy.

Advanced analytical modeling of double-gate Tunnel-FETs - A performance evaluation

NASA Astrophysics Data System (ADS)

Graef, Michael; Hosenfeld, Fabian; Horst, Fabian; Farokhnejad, Atieh; Hain, Franziska; Iñíguez, Benjamín; Kloes, Alexander

2018-03-01

The Tunnel-FET is one of the most promising devices to be the successor of the standard MOSFET due to its alternative current transport mechanism, which allows a smaller subthreshold slope than the physically limited 60 mV/dec of the MOSFET. Recently fabricated devices show smaller slopes already but mostly not over multiple decades of the current transfer characteristics. In this paper the performance limiting effects, occurring during the fabrication process of the device, such as doping profiles and midgap traps are analyzed by physics-based analytical models and their performance limiting abilities are determined. Additionally, performance enhancing possibilities, such as hetero-structures and ambipolarity improvements are introduced and discussed. An extensive double-gate n-Tunnel-FET model is presented, which meets the versatile device requirements and shows a good fit with TCAD simulations and measurement data.

Validation of Ion Chromatographic Method for Determination of Standard Inorganic Anions in Treated and Untreated Drinking Water

NASA Astrophysics Data System (ADS)

Ivanova, V.; Surleva, A.; Koleva, B.

2018-06-01

An ion chromatographic method for determination of fluoride, chloride, nitrate and sulphate in untreated and treated drinking waters was described. An automated 850 IC Professional, Metrohm system equipped with conductivity detector and Metrosep A Supp 7-250 (250 x 4 mm) column was used. The validation of the method was performed for simultaneous determination of all studied analytes and the results have showed that the validated method fits the requirements of the current water legislation. The main analytical characteristics were estimated for each of studied analytes: limits of detection, limits of quantification, working and linear ranges, repeatability and intermediate precision, recovery. The trueness of the method was estimated by analysis of certified reference material for soft drinking water. Recovery test was performed on spiked drinking water samples. An uncertainty was estimated. The method was applied for analysis of drinking waters before and after chlorination.

Cruise performance and range prediction reconsidered

NASA Astrophysics Data System (ADS)

Torenbeek, Egbert

1997-05-01

A unified analytical treatment of the cruise performance of subsonic transport aircraft is derived, valid for gas turbine powerplant installations: turboprop, turbojet and turbofan powered aircraft. Different from the classical treatment the present article deals with compressibility effects on the aerodynamic characteristics. Analytical criteria are derived for optimum cruise lift coefficient and Mach number, with and without constraints on the altitude and engine rating. A simple alternative to the Bréguet range equation is presented which applies to several practical cruising flight techniques: flight at constant altitude and Mach number and stepped cruise/climb. A practical non-iterative procedure for computing mission and reserve fuel loads in the preliminary design stage is proposed.

The effect of helicopter main rotor blade phasing and spacing on performance, blade loads, and acoustics

NASA Technical Reports Server (NTRS)

Gangwani, S. T.

1976-01-01

The performance, blade loads, and acoustic characteristics of a variable geometry rotor (VGR) system in forward flight and in a pullup maneuver were determined by the use of existing analytical programs. The investigation considered the independent effects of vertical separation of two three-bladed rotor systems as well as the effects of azimuthal spacing between the blades of the two rotors. The computations were done to determine the effects of these parameters on the performance, blade loads, and acoustic characteristics at two advance ratios in steady-state level flight and for two different g pullups at one advance ratio. To evaluate the potential benefits of the VGR concept in forward flight and pullup maneuvers, the results were compared as to performance, oscillatory blade loadings, vibratory forces transmitted to the fixed fuselage, and the rotor noise characteristics of the various VGR configurations with those of the conventional six-bladed rotor system.

SSME single crystal turbine blade dynamics

NASA Technical Reports Server (NTRS)

Moss, Larry A.; Smith, Todd E.

1987-01-01

A study was performed to determine the dynamic characteristics of the Space Shuttle main engine high pressure fuel turbopump (HPFTP) blades made of single crystal (SC) material. The first and second stage drive turbine blades of HPFTP were examined. The nonrotating natural frequencies were determined experimentally and analytically. The experimental results of the SC second stage blade were used to verify the analytical procedures. The analytical study examined the SC first stage blade natural frequencies with respect to crystal orientation at typical operating conditions. The SC blade dynamic response was predicted to be less than the directionally solidified blade. Crystal axis orientation optimization indicated the third mode interference will exist in any SC orientation.

The noncavitating performance and life of a small vane-type positive displacement pump in liquid hydrogen

NASA Technical Reports Server (NTRS)

Ulbricht, T. E.; Hemminger, J. A.

1986-01-01

The low flow rate and high head rise requirements of hydrogen/oxygen auxiliary propulsion systems make the application of centrifugal pumps difficult. Positive displacement pumps are well-suited for these flow conditions, but little is known about their performance and life characteristics in liquid hydrogen. An experimental and analytical investigation was conducted to determine the performance and life characteristics of a vane-type, positive displacement pump. In the experimental part of this effort, mass flow rate and shaft torque were determined as functions of shaft speed and pump pressure rise. Since liquid hydrogen offers little lubrication in a rubbing situation, pump life is an issue. During the life test, the pump was operated intermittently for 10 hr at the steady-state point of 0.074 lbm/sec (0.03 kg/sec) flow rate, 3000 psid (2.07 MPa) pressure rise, and 8000 rpm (838 rad/sec) shaft speed. Pump performance was monitored during the life test series and the results indicated no loss in performance. Material loss from the vanes was recorded and wear of the other components was documented. In the analytical part of this effort, a comprehensive pump performance analysis computer code, developed in-house, was used to predict pump performance. The results of the experimental investigation are presented and compared with the results of the analysis. Results of the life test are also presented.

Analytical and pre-analytical performance characteristics of a novel cartridge-type blood gas analyzer for point-of-care and laboratory testing.

PubMed

Oyaert, Matthijs; Van Maerken, Tom; Bridts, Silke; Van Loon, Silvi; Laverge, Heleen; Stove, Veronique

2018-03-01

Point-of-care blood gas test results may benefit therapeutic decision making by their immediate impact on patient care. We evaluated the (pre-)analytical performance of a novel cartridge-type blood gas analyzer, the GEM Premier 5000 (Werfen), for the determination of pH, partial carbon dioxide pressure (pCO 2 ), partial oxygen pressure (pO 2 ), sodium (Na + ), potassium (K + ), chloride (Cl - ), ionized calcium ( i Ca 2+ ), glucose, lactate, and total hemoglobin (tHb). Total imprecision was estimated according to the CLSI EP5-A2 protocol. The estimated total error was calculated based on the mean of the range claimed by the manufacturer. Based on the CLSI EP9-A2 evaluation protocol, a method comparison with the Siemens RapidPoint 500 and Abbott i-STAT CG8+ was performed. Obtained data were compared against preset quality specifications. Interference of potential pre-analytical confounders on co-oximetry and electrolyte concentrations were studied. The analytical performance was acceptable for all parameters tested. Method comparison demonstrated good agreement to the RapidPoint 500 and i-STAT CG8+, except for some parameters (RapidPoint 500: pCO 2 , K + , lactate and tHb; i-STAT CG8+: pO 2 , Na + , i Ca 2+ and tHb) for which significant differences between analyzers were recorded. No interference of lipemia or methylene blue on CO-oximetry results was found. On the contrary, significant interference for benzalkonium and hemolysis on electrolyte measurements were found, for which the user is notified by an interferent specific flag. Identification of sample errors from pre-analytical sources, such as interferences and automatic corrective actions, along with the analytical performance, ease of use and low maintenance time of the instrument, makes the evaluated instrument a suitable blood gas analyzer for both POCT and laboratory use. Copyright © 2018 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

10 CFR 431.17 - Determination of efficiency.

Code of Federal Regulations, 2014 CFR

2014-01-01

... characteristics of that basic model, and (ii) Based on engineering or statistical analysis, computer simulation or... simulation or modeling, and other analytic evaluation of performance data on which the AEDM is based... applied. (iii) If requested by the Department, the manufacturer shall conduct simulations to predict the...

10 CFR 431.17 - Determination of efficiency.

Code of Federal Regulations, 2012 CFR

2012-01-01

... characteristics of that basic model, and (ii) Based on engineering or statistical analysis, computer simulation or... simulation or modeling, and other analytic evaluation of performance data on which the AEDM is based... applied. (iii) If requested by the Department, the manufacturer shall conduct simulations to predict the...

An analytical technique for predicting the characteristics of a flexible wing equipped with an active flutter-suppression system and comparison with wind-tunnel data

NASA Technical Reports Server (NTRS)

Abel, I.

1979-01-01

An analytical technique for predicting the performance of an active flutter-suppression system is presented. This technique is based on the use of an interpolating function to approximate the unsteady aerodynamics. The resulting equations are formulated in terms of linear, ordinary differential equations with constant coefficients. This technique is then applied to an aeroelastic model wing equipped with an active flutter-suppression system. Comparisons between wind-tunnel data and analysis are presented for the wing both with and without active flutter suppression. Results indicate that the wing flutter characteristics without flutter suppression can be predicted very well but that a more adequate model of wind-tunnel turbulence is required when the active flutter-suppression system is used.

An Illumination- and Temperature-Dependent Analytical Model for Copper Indium Gallium Diselenide (CIGS) Solar Cells

DOE PAGES

Sun, Xingshu; Silverman, Timothy; Garris, Rebekah; ...

2016-07-18

In this study, we present a physics-based analytical model for copper indium gallium diselenide (CIGS) solar cells that describes the illumination- and temperature-dependent current-voltage (I-V) characteristics and accounts for the statistical shunt variation of each cell. The model is derived by solving the drift-diffusion transport equation so that its parameters are physical and, therefore, can be obtained from independent characterization experiments. The model is validated against CIGS I-V characteristics as a function of temperature and illumination intensity. This physics-based model can be integrated into a large-scale simulation framework to optimize the performance of solar modules, as well as predict themore » long-term output yields of photovoltaic farms under different environmental conditions.« less

Analytical model of surface potential profiles and transfer characteristics for hetero stacked tunnel field-effect transistors

NASA Astrophysics Data System (ADS)

Xu, Hui Fang; Sun, Wen; Han, Xin Feng

2018-06-01

An analytical model of surface potential profiles and transfer characteristics for hetero stacked tunnel field-effect transistors (HS-TFETs) is presented for the first time, where hetero stacked materials are composed of two different bandgaps. The bandgap of the underlying layer is smaller than that of the upper layer. Under different device parameters (upper layer thickness, underlying layer thickness, and hetero stacked materials) and temperature, the validity of the model is demonstrated by the agreement of its results with the simulation results. Moreover, the results show that the HS-TFETs can obtain predominant performance with relatively slow changes of subthreshold swing (SS) over a wide drain current range, steep average subthreshold swing, high on-state current, and large on–off state current ratio.

Performance characteristics of an ion chromatographic method for the quantitation of citrate and phosphate in pharmaceutical solutions.

PubMed

Jenke, Dennis; Sadain, Salma; Nunez, Karen; Byrne, Frances

2007-01-01

The performance of an ion chromatographic method for measuring citrate and phosphate in pharmaceutical solutions is evaluated. Performance characteristics examined include accuracy, precision, specificity, response linearity, robustness, and the ability to meet system suitability criteria. In general, the method is found to be robust within reasonable deviations from its specified operating conditions. Analytical accuracy is typically 100 +/- 3%, and short-term precision is not more than 1.5% relative standard deviation. The instrument response is linear over a range of 50% to 150% of the standard preparation target concentrations (12 mg/L for phosphate and 20 mg/L for citrate), and the results obtained using a single-point standard versus a calibration curve are essentially equivalent. A small analytical bias is observed and ascribed to the relative purity of the differing salts, used as raw materials in tested finished products and as reference standards in the analytical method. The assay is specific in that no phosphate or citrate peaks are observed in a variety of method-related solutions and matrix blanks (with and without autoclaving). The assay with manual preparation of the eluents is sensitive to the composition of the eluent in the sense that the eluent must be effectively degassed and protected from CO(2) ingress during use. In order for the assay to perform effectively, extensive system equilibration and conditioning is required. However, a properly conditioned and equilibrated system can be used to test a number of samples via chromatographic runs that include many (> 50) injections.

JT8D and JT9D jet engine performance improvement program. Task 1: Feasibility analysis

NASA Technical Reports Server (NTRS)

Gaffin, W. O.; Webb, D. E.

1979-01-01

JT8D and JT9D component performance improvement concepts which have a high probability of incorporation into production engines were identified and ranked. An evaluation method based on airline payback period was developed for the purpose of identifying the most promising concepts. The method used available test data and analytical models along with conceptual/preliminary designs to predict the performance improvements, weight, installation characteristics, cost for new production and retrofit, maintenance cost, and qualitative characteristics of candidate concepts. These results were used to arrive at the concept payback period, which is the time required for an airline to recover the investment cost of concept implementation.

Rotordynamic Instability Problems in High-Performance Turbomachinery, 1986

NASA Technical Reports Server (NTRS)

1987-01-01

The first rotordynamics workshop proceedings (NASA CP-2133, 1980) emphasized a feeling of uncertainty in predicting the stability of characteristics of high-performance turbomachinery. In the second workshop proceedings (NASA CP-2250, 1982) these uncertainities were reduced through programs established to systematically resolve problems, with emphasis on experimental validiation of the forces that influence rotordynamics. In third proceedings (NASA CP-2338, 1984) many programs for predicting or measuring forces and force coefficients in high-performance turbomachinery produced results. Data became available for designing new machines with enhanced stability characteristics or for upgrading existing machines. The present workshop proceedings illustrates a continued trend toward a more unified view of rotordynamic instability problems and several encouraging new analytical developments.

Flight simulator fidelity assessment in a rotorcraft lateral translation maneuver

NASA Technical Reports Server (NTRS)

Hess, R. A.; Malsbury, T.; Atencio, A., Jr.

1992-01-01

A model-based methodology for assessing flight simulator fidelity in closed-loop fashion is exercised in analyzing a rotorcraft low-altitude maneuver for which flight test and simulation results were available. The addition of a handling qualities sensitivity function to a previously developed model-based assessment criteria allows an analytical comparison of both performance and handling qualities between simulation and flight test. Model predictions regarding the existence of simulator fidelity problems are corroborated by experiment. The modeling approach is used to assess analytically the effects of modifying simulator characteristics on simulator fidelity.

On-orbit evaluation of the control system/structural mode interactions on OSO-8

NASA Technical Reports Server (NTRS)

Slafer, L. I.

1980-01-01

The Orbiting Solar Observatory-8 experienced severe structural mode/control loop interaction problems during the spacecraft development. Extensive analytical studies, using the hybrid coordinate modeling approach, and comprehensive ground testing were carried out in order to achieve the system's precision pointing performance requirements. A recent series of flight tests were conducted with the spacecraft in which a wide bandwidth, high resolution telemetry system was utilized to evaluate the on-orbit flexible dynamics characteristics of the vehicle along with the control system performance. This paper describes the results of these tests, reviewing the basic design problem, analytical approach taken, ground test philosophy, and on-orbit testing. Data from the tests was used to determine the primary mode frequency, damping, and servo coupling dynamics for the on-orbit condition. Additionally, the test results have verified analytically predicted differences between the on-orbit and ground test environments. The test results have led to a validation of both the analytical modeling and servo design techniques used during the development of the control system, and also verified the approach taken to vehicle and servo ground testing.

Numerical implementation of complex orthogonalization, parallel transport on Stiefel bundles, and analyticity

NASA Astrophysics Data System (ADS)

Avitabile, Daniele; Bridges, Thomas J.

2010-06-01

Numerical integration of complex linear systems of ODEs depending analytically on an eigenvalue parameter are considered. Complex orthogonalization, which is required to stabilize the numerical integration, results in non-analytic systems. It is shown that properties of eigenvalues are still efficiently recoverable by extracting information from a non-analytic characteristic function. The orthonormal systems are constructed using the geometry of Stiefel bundles. Different forms of continuous orthogonalization in the literature are shown to correspond to different choices of connection one-form on the Stiefel bundle. For the numerical integration, Gauss-Legendre Runge-Kutta algorithms are the principal choice for preserving orthogonality, and performance results are shown for a range of GLRK methods. The theory and methods are tested by application to example boundary value problems including the Orr-Sommerfeld equation in hydrodynamic stability.

Fault feature analysis of cracked gear based on LOD and analytical-FE method

NASA Astrophysics Data System (ADS)

Wu, Jiateng; Yang, Yu; Yang, Xingkai; Cheng, Junsheng

2018-01-01

At present, there are two main ideas for gear fault diagnosis. One is the model-based gear dynamic analysis; the other is signal-based gear vibration diagnosis. In this paper, a method for fault feature analysis of gear crack is presented, which combines the advantages of dynamic modeling and signal processing. Firstly, a new time-frequency analysis method called local oscillatory-characteristic decomposition (LOD) is proposed, which has the attractive feature of extracting fault characteristic efficiently and accurately. Secondly, an analytical-finite element (analytical-FE) method which is called assist-stress intensity factor (assist-SIF) gear contact model, is put forward to calculate the time-varying mesh stiffness (TVMS) under different crack states. Based on the dynamic model of the gear system with 6 degrees of freedom, the dynamic simulation response was obtained for different tooth crack depths. For the dynamic model, the corresponding relation between the characteristic parameters and the degree of the tooth crack is established under a specific condition. On the basis of the methods mentioned above, a novel gear tooth root crack diagnosis method which combines the LOD with the analytical-FE is proposed. Furthermore, empirical mode decomposition (EMD) and ensemble empirical mode decomposition (EEMD) are contrasted with the LOD by gear crack fault vibration signals. The analysis results indicate that the proposed method performs effectively and feasibility for the tooth crack stiffness calculation and the gear tooth crack fault diagnosis.

An approach to the design of wide-angle optical systems with special illumination and IFOV requirements

NASA Astrophysics Data System (ADS)

Pravdivtsev, Andrey V.

2012-06-01

The article presents the approach to the design wide-angle optical systems with special illumination and instantaneous field of view (IFOV) requirements. The unevenness of illumination reduces the dynamic range of the system, which negatively influence on the system ability to perform their task. The result illumination on the detector depends among other factors from the IFOV changes. It is also necessary to consider IFOV in the synthesis of data processing algorithms, as it directly affects to the potential "signal/background" ratio for the case of statistically homogeneous backgrounds. A numerical-analytical approach that simplifies the design of wideangle optical systems with special illumination and IFOV requirements is presented. The solution can be used for optical systems which field of view greater than 180 degrees. Illumination calculation in optical CAD is based on computationally expensive tracing of large number of rays. The author proposes to use analytical expression for some characteristics which illumination depends on. The rest characteristic are determined numerically in calculation with less computationally expensive operands, the calculation performs not every optimization step. The results of analytical calculation inserts in the merit function of optical CAD optimizer. As a result we reduce the optimizer load, since using less computationally expensive operands. It allows reducing time and resources required to develop a system with the desired characteristics. The proposed approach simplifies the creation and understanding of the requirements for the quality of the optical system, reduces the time and resources required to develop an optical system, and allows creating more efficient EOS.

Pseudo-beam method for compressive buckling characteristics analysis of space inflatable load-carrying structures

NASA Astrophysics Data System (ADS)

Wang, Changguo; Tan, Huifeng; Du, Xingwen

2009-10-01

This paper extends Le van’s work to the case of nonlinear problem and the complicated configuration. The wrinkling stress distribution and the pressure effects are also included in our analysis. Pseudo-beam method is presented based on the inflatable beam theory to model the inflatable structures as a set of inflatable beam elements with a pre-stressed state. In this method, the discretized nonlinear equations are given based upon the virtual work principle with a 3-node Timoshenko’s beam model. Finite element simulation is performed by using a 3-node BEAM189 element incorporating ANSYS nonlinear program. The pressure effect is equivalent included in our method by modifying beam element cross-section parameters related to pressure. A benchmark example, the bending case of an inflatable cantilever beam, is performed to verify the accuracy of our proposed method. The comparisons reveal that the numerical results obtained with our method are close to open published analytical and membrane finite element results. The method is then used to evaluate the whole buckling and the load-carrying characteristics of an inflatable support frame subjected to a compression force. The wrinkling stress and region characteristics are also shown in the end. This method gives better convergence characteristics, and requires much less computation time. It is very effective to deal with the whole load-carrying ability analytical problems for large scale inflatable structures with complex configuration.

Validating a faster method for reconstitution of Crotalidae Polyvalent Immune Fab (ovine).

PubMed

Gerring, David; King, Thomas R; Branton, Richard

2013-07-01

Reconstitution of CroFab(®) (Crotalidae Polyvalent Immune Fab [ovine]) lyophilized drug product was previously performed using 10 mL sterile water for injection followed by up to 36 min of gentle swirling of the vial. CroFab has been clinically demonstrated to be most effective when administered within 6 h of snake envenomation, and improved clinical outcomes are correlated with quicker timing of administration. An alternate reconstitution method was devised, using 18 mL 0.9% saline with manual inversion, with the goal of shortening reconstitution time while maintaining a high quality, efficacious product. An analytical study was designed to compare the physicochemical properties of 3 separate batches of CroFab when reconstituted using the standard procedure (10 mL WFI with gentle swirling) and a modified rapid procedure using 18 mL 0.9% saline and manual inversion. The physical and chemical characteristics of the same 3 batches were assessed using various analytic methodologies associated with routine quality control release testing. In addition further analytical methodologies were applied in order to elucidate possible structural changes that may be induced by the changed reconstitution procedure. Batches A, B, and C required mean reconstitution times of 25 min 51 s using the label method and 3 min 07 s (a 88.0% mean decrease) using the modified method. Physicochemical characteristics (color and clarity, pH, purity, protein content, potency) were found to be highly comparable. Characterization assays (dynamic light scattering, analytical ultracentrifugation, LC-MS, SDS-PAGE and circular dichroism spectroscopy were also all found to be comparable between methods. When comparing CroFab batches that were reconstituted using the labeled and modified methods, the physicochemical and biological (potency) characteristics of CroFab were not significantly changed when challenged by the various standard analytical methodologies applied in routine quality control analysis. Additionally, no changes in the CroFab molecule regarding degradation, aggregation, purity, structure, or mass were observed. The analyses performed validated the use of the more rapid reconstitution method using 18 mL 0.9% saline in order to allow a significantly reduced time to administration of CroFab to patients in need. Copyright © 2013 Elsevier Ltd. All rights reserved.

Evaluation of space shuttle main engine fluid dynamic frequency response characteristics

NASA Technical Reports Server (NTRS)

Gardner, T. G.

1980-01-01

In order to determine the POGO stability characteristics of the space shuttle main engine liquid oxygen (LOX) system, the fluid dynamic frequency response functions between elements in the SSME LOX system was evaluated, both analytically and experimentally. For the experimental data evaluation, a software package was written for the Hewlett-Packard 5451C Fourier analyzer. The POGO analysis software is documented and consists of five separate segments. Each segment is stored on the 5451C disc as an individual program and performs its own unique function. Two separate data reduction methods, a signal calibration, coherence or pulser signal based frequency response function blanking, and automatic plotting features are included in the program. The 5451C allows variable parameter transfer from program to program. This feature is used to advantage and requires only minimal user interface during the data reduction process. Experimental results are included and compared with the analytical predictions in order to adjust the general model and arrive at a realistic simulation of the POGO characteristics.

Hydrogen-oxygen auxiliary propulsion for the space shuttle. Volume 1: High pressure thrusters

NASA Technical Reports Server (NTRS)

1973-01-01

Technology for long life, high performing, gaseous hydrogen-gaseous oxygen rocket engines suitable for auxiliary propulsion was provided by a combined analytical and experimental program. Propellant injectors, fast response valves, igniters, and regeneratively and film-cooled thrust chambers were tested over a wide range of operating conditions. Data generated include performance, combustion efficiency, thermal characteristics film cooling effectiveness, dynamic response in pulsing, and cycle life limitations.

Performance evaluation method of electric energy data acquire system based on combination of subjective and objective weights

NASA Astrophysics Data System (ADS)

Gao, Chen; Ding, Zhongan; Deng, Bofa; Yan, Shengteng

2017-10-01

According to the characteristics of electric energy data acquire system (EEDAS), considering the availability of each index data and the connection between the index integrity, establishing the performance evaluation index system of electric energy data acquire system from three aspects as master station system, communication channel, terminal equipment. To determine the comprehensive weight of each index based on triangular fuzzy number analytic hierarchy process with entropy weight method, and both subjective preference and objective attribute are taken into consideration, thus realize the performance comprehensive evaluation more reasonable and reliable. Example analysis shows that, by combination with analytic hierarchy process (AHP) and triangle fuzzy numbers (TFN) to establish comprehensive index evaluation system based on entropy method, the evaluation results not only convenient and practical, but also more objective and accurate.

Early warning systems for the management of chronic heart failure: a systematic literature review of cost-effectiveness models.

PubMed

Albuquerque De Almeida, Fernando; Al, Maiwenn; Koymans, Ron; Caliskan, Kadir; Kerstens, Ankie; Severens, Johan L

2018-04-01

Describing the general and methodological characteristics of decision-analytical models used in the economic evaluation of early warning systems for the management of chronic heart failure patients and performing a quality assessment of their methodological characteristics is expected to provide concise and useful insight to inform the future development of decision-analytical models in the field of heart failure management. Areas covered: The literature on decision-analytical models for the economic evaluation of early warning systems for the management of chronic heart failure patients was systematically reviewed. Nine electronic databases were searched through the combination of synonyms for heart failure and sensitive filters for cost-effectiveness and early warning systems. Expert commentary: The retrieved models show some variability with regards to their general study characteristics. Overall, they display satisfactory methodological quality, even though some points could be improved, namely on the consideration and discussion of any competing theories regarding model structure and disease progression, identification of key parameters and the use of expert opinion, and uncertainty analyses. A comprehensive definition of early warning systems and further research under this label should be pursued. To improve the transparency of economic evaluation publications, authors should make available detailed technical information regarding the published models.

Effect of vibration on retention characteristics of screen acquisition systems. [for surface tension propellant acquisition

NASA Technical Reports Server (NTRS)

Tegart, J. R.; Aydelott, J. C.

1978-01-01

The design of surface tension propellant acquisition systems using fine-mesh screen must take into account all factors that influence the liquid pressure differentials within the system. One of those factors is spacecraft vibration. Analytical models to predict the effects of vibration have been developed. A test program to verify the analytical models and to allow a comparative evaluation of the parameters influencing the response to vibration was performed. Screen specimens were tested under conditions simulating the operation of an acquisition system, considering the effects of such parameters as screen orientation and configuration, screen support method, screen mesh, liquid flow and liquid properties. An analytical model, based on empirical coefficients, was most successful in predicting the effects of vibration.

Propulsion requirements for communications satellites.

NASA Technical Reports Server (NTRS)

Isley, W. C.; Duck, K. I.

1972-01-01

The concept of characteristics thrust is introduced herein as a means of classifying propulsion system tasks related particularly to geosynchronous communications spacecraft. Approximate analytical models are developed to permit estimation of characteristic thrust for injection error corrections, orbit angle re-location, north-south station keeping, east-west station keeping, spin axis precession control, attitude rate damping, and orbit raising applications. Performance assessment factors are then outlined in terms of characteristic power, characteristic weight, and characteristic volume envelope, which are related to the characteristic thrust. Finally, selected performance curves are shown for power as a function of spacecraft weight, including the influence of duty cycle on north-south station keeping, a 90 degree orbit angle re-location in 14 days, and finally comparison of orbit raising tasks from low and intermediate orbits to a final geosynchronous station. Power requirements range from less than 75 watts for north-south station keeping on small payloads up to greater than 15 KW for a 180 day orbit raising mission including a 28.5 degree plane change.

Measurements and Predictions for a Distributed Exhaust Nozzle

NASA Technical Reports Server (NTRS)

Kinzie, Kevin W.; Brown, Martha C.; Schein, David B.; Solomon, W. David, Jr.

2001-01-01

The acoustic and aerodynamic performance characteristics of a distributed exhaust nozzle (DEN) design concept were evaluated experimentally and analytically with the purpose of developing a design methodology for developing future DEN technology. Aerodynamic and acoustic measurements were made to evaluate the DEN performance and the CFD design tool. While the CFD approach did provide an excellent prediction of the flowfield and aerodynamic performance characteristics of the DEN and 2D reference nozzle, the measured acoustic suppression potential of this particular DEN was low. The measurements and predictions indicated that the mini-exhaust jets comprising the distributed exhaust coalesced back into a single stream jet very shortly after leaving the nozzles. Even so, the database provided here will be useful for future distributed exhaust designs with greater noise reduction and aerodynamic performance potential.

Analytical criteria for performance characteristics of IgE binding methods for evaluating safety of biotech food products.

PubMed

Holzhauser, Thomas; Ree, Ronald van; Poulsen, Lars K; Bannon, Gary A

2008-10-01

There is detailed guidance on how to perform bioinformatic analyses and enzymatic degradation studies for genetically modified crops under consideration for approval by regulatory agencies; however, there is no consensus in the scientific community on the details of how to perform IgE serum studies. IgE serum studies are an important safety component to acceptance of genetically modified crops when the introduced protein is novel, the introduced protein is similar to known allergens, or the crop is allergenic. In this manuscript, we describe the characteristics of the reagents, validation of assay performance, and data analysis necessary to optimize the information obtained from serum testing of novel proteins and genetically modified (GM) crops and to make results more accurate and comparable between different investigations.

The analytical validation of the Oncotype DX Recurrence Score assay

PubMed Central

Baehner, Frederick L

2016-01-01

In vitro diagnostic multivariate index assays are highly complex molecular assays that can provide clinically actionable information regarding the underlying tumour biology and facilitate personalised treatment. These assays are only useful in clinical practice if all of the following are established: analytical validation (i.e., how accurately/reliably the assay measures the molecular characteristics), clinical validation (i.e., how consistently/accurately the test detects/predicts the outcomes of interest), and clinical utility (i.e., how likely the test is to significantly improve patient outcomes). In considering the use of these assays, clinicians often focus primarily on the clinical validity/utility; however, the analytical validity of an assay (e.g., its accuracy, reproducibility, and standardisation) should also be evaluated and carefully considered. This review focuses on the rigorous analytical validation and performance of the Oncotype DX® Breast Cancer Assay, which is performed at the Central Clinical Reference Laboratory of Genomic Health, Inc. The assay process includes tumour tissue enrichment (if needed), RNA extraction, gene expression quantitation (using a gene panel consisting of 16 cancer genes plus 5 reference genes and quantitative real-time RT-PCR), and an automated computer algorithm to produce a Recurrence Score® result (scale: 0–100). This review presents evidence showing that the Recurrence Score result reported for each patient falls within a tight clinically relevant confidence interval. Specifically, the review discusses how the development of the assay was designed to optimise assay performance, presents data supporting its analytical validity, and describes the quality control and assurance programmes that ensure optimal test performance over time. PMID:27729940

The analytical validation of the Oncotype DX Recurrence Score assay.

PubMed

Baehner, Frederick L

2016-01-01

In vitro diagnostic multivariate index assays are highly complex molecular assays that can provide clinically actionable information regarding the underlying tumour biology and facilitate personalised treatment. These assays are only useful in clinical practice if all of the following are established: analytical validation (i.e., how accurately/reliably the assay measures the molecular characteristics), clinical validation (i.e., how consistently/accurately the test detects/predicts the outcomes of interest), and clinical utility (i.e., how likely the test is to significantly improve patient outcomes). In considering the use of these assays, clinicians often focus primarily on the clinical validity/utility; however, the analytical validity of an assay (e.g., its accuracy, reproducibility, and standardisation) should also be evaluated and carefully considered. This review focuses on the rigorous analytical validation and performance of the Oncotype DX ® Breast Cancer Assay, which is performed at the Central Clinical Reference Laboratory of Genomic Health, Inc. The assay process includes tumour tissue enrichment (if needed), RNA extraction, gene expression quantitation (using a gene panel consisting of 16 cancer genes plus 5 reference genes and quantitative real-time RT-PCR), and an automated computer algorithm to produce a Recurrence Score ® result (scale: 0-100). This review presents evidence showing that the Recurrence Score result reported for each patient falls within a tight clinically relevant confidence interval. Specifically, the review discusses how the development of the assay was designed to optimise assay performance, presents data supporting its analytical validity, and describes the quality control and assurance programmes that ensure optimal test performance over time.

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.

MS-Based Analytical Techniques: Advances in Spray-Based Methods and EI-LC-MS Applications

PubMed Central

Medina, Isabel; Cappiello, Achille; Careri, Maria

2018-01-01

Mass spectrometry is the most powerful technique for the detection and identification of organic compounds. It can provide molecular weight information and a wealth of structural details that give a unique fingerprint for each analyte. Due to these characteristics, mass spectrometry-based analytical methods are showing an increasing interest in the scientific community, especially in food safety, environmental, and forensic investigation areas where the simultaneous detection of targeted and nontargeted compounds represents a key factor. In addition, safety risks can be identified at the early stage through online and real-time analytical methodologies. In this context, several efforts have been made to achieve analytical instrumentation able to perform real-time analysis in the native environment of samples and to generate highly informative spectra. This review article provides a survey of some instrumental innovations and their applications with particular attention to spray-based MS methods and food analysis issues. The survey will attempt to cover the state of the art from 2012 up to 2017. PMID:29850370

Uncertainty estimates of purity measurements based on current information: toward a "live validation" of purity methods.

PubMed

Apostol, Izydor; Kelner, Drew; Jiang, Xinzhao Grace; Huang, Gang; Wypych, Jette; Zhang, Xin; Gastwirt, Jessica; Chen, Kenneth; Fodor, Szilan; Hapuarachchi, Suminda; Meriage, Dave; Ye, Frank; Poppe, Leszek; Szpankowski, Wojciech

2012-12-01

To predict precision and other performance characteristics of chromatographic purity methods, which represent the most widely used form of analysis in the biopharmaceutical industry. We have conducted a comprehensive survey of purity methods, and show that all performance characteristics fall within narrow measurement ranges. This observation was used to develop a model called Uncertainty Based on Current Information (UBCI), which expresses these performance characteristics as a function of the signal and noise levels, hardware specifications, and software settings. We applied the UCBI model to assess the uncertainty of purity measurements, and compared the results to those from conventional qualification. We demonstrated that the UBCI model is suitable to dynamically assess method performance characteristics, based on information extracted from individual chromatograms. The model provides an opportunity for streamlining qualification and validation studies by implementing a "live validation" of test results utilizing UBCI as a concurrent assessment of measurement uncertainty. Therefore, UBCI can potentially mitigate the challenges associated with laborious conventional method validation and facilitates the introduction of more advanced analytical technologies during the method lifecycle.

Bench-top validation testing of selected immunological and molecular Renibacterium salmoninarum diagnostic assays by comparison with quantitative bacteriological culture

USGS Publications Warehouse

Elliott, D.G.; Applegate, L.J.; Murray, A.L.; Purcell, M.K.; McKibben, C.L.

2013-01-01

No gold standard assay exhibiting error-free classification of results has been identified for detection of Renibacterium salmoninarum, the causative agent of salmonid bacterial kidney disease. Validation of diagnostic assays for R. salmoninarum has been hindered by its unique characteristics and biology, and difficulties in locating suitable populations of reference test animals. Infection status of fish in test populations is often unknown, and it is commonly assumed that the assay yielding the most positive results has the highest diagnostic accuracy, without consideration of misclassification of results. In this research, quantification of R. salmoninarum in samples by bacteriological culture provided a standardized measure of viable bacteria to evaluate analytical performance characteristics (sensitivity, specificity and repeatability) of non-culture assays in three matrices (phosphate-buffered saline, ovarian fluid and kidney tissue). Non-culture assays included polyclonal enzyme-linked immunosorbent assay (ELISA), direct smear fluorescent antibody technique (FAT), membrane-filtration FAT, nested polymerase chain reaction (nested PCR) and three real-time quantitative PCR assays. Injection challenge of specific pathogen-free Chinook salmon, Oncorhynchus tshawytscha (Walbaum), with R. salmoninarum was used to estimate diagnostic sensitivity and specificity. Results did not identify a single assay demonstrating the highest analytical and diagnostic performance characteristics, but revealed strengths and weaknesses of each test.

New insight into the comparative power of quality-control rules that use control observations within a single analytical run.

PubMed

Parvin, C A

1993-03-01

The error detection characteristics of quality-control (QC) rules that use control observations within a single analytical run are investigated. Unlike the evaluation of QC rules that span multiple analytical runs, most of the fundamental results regarding the performance of QC rules applied within a single analytical run can be obtained from statistical theory, without the need for simulation studies. The case of two control observations per run is investigated for ease of graphical display, but the conclusions can be extended to more than two control observations per run. Results are summarized in a graphical format that offers many interesting insights into the relations among the various QC rules. The graphs provide heuristic support to the theoretical conclusions that no QC rule is best under all error conditions, but the multirule that combines the mean rule and a within-run standard deviation rule offers an attractive compromise.

Cross-stream diffusion under pressure-driven flow in microchannels with arbitrary aspect ratios: a phase diagram study using a three-dimensional analytical model

PubMed Central

Song, Hongjun; Wang, Yi; Pant, Kapil

2011-01-01

This article presents a three-dimensional analytical model to investigate cross-stream diffusion transport in rectangular microchannels with arbitrary aspect ratios under pressure-driven flow. The Fourier series solution to the three-dimensional convection–diffusion equation is obtained using a double integral transformation method and associated eigensystem calculation. A phase diagram derived from the dimensional analysis is presented to thoroughly interrogate the characteristics in various transport regimes and examine the validity of the model. The analytical model is verified against both experimental and numerical models in terms of the concentration profile, diffusion scaling law, and mixing efficiency with excellent agreement (with <0.5% relative error). Quantitative comparison against other prior analytical models in extensive parameter space is also performed, which demonstrates that the present model accommodates much broader transport regimes with significantly enhanced applicability. PMID:22247719

Cross-stream diffusion under pressure-driven flow in microchannels with arbitrary aspect ratios: a phase diagram study using a three-dimensional analytical model.

PubMed

Song, Hongjun; Wang, Yi; Pant, Kapil

2012-01-01

This article presents a three-dimensional analytical model to investigate cross-stream diffusion transport in rectangular microchannels with arbitrary aspect ratios under pressure-driven flow. The Fourier series solution to the three-dimensional convection-diffusion equation is obtained using a double integral transformation method and associated eigensystem calculation. A phase diagram derived from the dimensional analysis is presented to thoroughly interrogate the characteristics in various transport regimes and examine the validity of the model. The analytical model is verified against both experimental and numerical models in terms of the concentration profile, diffusion scaling law, and mixing efficiency with excellent agreement (with <0.5% relative error). Quantitative comparison against other prior analytical models in extensive parameter space is also performed, which demonstrates that the present model accommodates much broader transport regimes with significantly enhanced applicability.

Modeling of a rotary motor driven by an anisotropic piezoelectric composite laminate.

PubMed

Zhu, M L; Lee, S R; Zhang, T Y; Tong, P

2000-01-01

This paper proposes an analytical model of a rotary motor driven by an anisotropic piezoelectric composite laminate. The driving element of the motor is a three-layer laminated plate. A piezoelectric layer is sandwiched between two anti-symmetric composite laminae. Because of the material anisotropy and the anti-symmetric configuration, torsional vibration can be induced through the inplane strain actuated by the piezoelectric layer. The advantages of the motor are its magnetic field immunity, simple structure, easy maintenance, low cost, and good low-speed performance. In this paper, the motor is considered to be a coupled dynamic system. The analytical model includes the longitudinal and torsional vibrations of the laminate and the rotating motion of the rotor under action of contact forces. The analytical model can predict the overall characteristics of the motor, including the modal frequency and the response of motion of the laminate, the rotating speed of the rotor, the input power, the output power, and the efficiency of the motor. The effects of the initial compressive force, the applied voltage, the moment of rotor inertia, and the frictional coefficient of the contact interface on the characteristics of the motor are simulated and discussed. A selection of the numerical results from the analytical model is confirmed by experimental data.

Determination of dissolved bromate in drinking water by ion chromatography and post column reaction: interlaboratory study.

PubMed

Cordeiro, Fernando; Robouch, Piotr; de la Calle, Maria Beatriz; Emteborg, Håkan; Charoud-Got, Jean; Schmitz, Franz

2011-01-01

A collaborative study, International Evaluation Measurement Programme-25a, was conducted in accordance with international protocols to determine the performance characteristics of an analytical method for the determination of dissolved bromate in drinking water. The method should fulfill the analytical requirements of Council Directive 98/83/EC (referred to in this work as the Drinking Water Directive; DWD). The new draft standard method under investigation is based on ion chromatography followed by post-column reaction and UV detection. The collaborating laboratories used the Draft International Organization for Standardization (ISO)/Draft International Standard (DIS) 11206 document. The existing standard method (ISO 15061:2001) is based on ion chromatography using suppressed conductivity detection, in which a preconcentration step may be required for the determination of bromate concentrations as low as 3 to 5 microg/L. The new method includes a dilution step that reduces the matrix effects, thus allowing the determination of bromate concentrations down to 0.5 microg/L. Furthermore, the method aims to minimize any potential interference of chlorite ions. The collaborative study investigated different types of drinking water, such as soft, hard, and mineral water. Other types of water, such as raw water (untreated), swimming pool water, a blank (named river water), and a bromate standard solution, were included as test samples. All test matrixes except the swimming pool water were spiked with high-purity potassium bromate to obtain bromate concentrations ranging from 1.67 to 10.0 microg/L. Swimming pool water was not spiked, as this water was incurred with bromate. Test samples were dispatched to 17 laboratories from nine different countries. Sixteen participants reported results. The repeatability RSD (RSD(r)) ranged from 1.2 to 4.1%, while the reproducibility RSD (RSDR) ranged from 2.3 to 5.9%. These precision characteristics compare favorably with those of ISO 15601. A thorough comparison of the performance characteristics is presented in this report. All method performance characteristics obtained in the frame of this collaborative study indicate that the draft ISO/DIS 11206 standard method meets the requirements set down by the DWD. It can, therefore, be considered to fit its intended analytical purpose.

Sulphured Polyacrylonitrile Composite Analysed by in operando UV-Visible Spectroscopy and 4-electrode Swagelok Cell.

PubMed

Dominko, Robert; Patel, Manu U M; Bele, Marjan; Pejovnik, Stane

2016-01-01

The electrochemical characteristics of sulfurized polyacrylonitrile composite (PAN/S) cathodes were compared with the commonly used carbon/S-based composite material. The difference in the working mechanism of these composites was examined. Analytical investigations were performed on both kinds of cathode electrode composites by using two reliable analytical techniques, in-situ UV-Visible spectroscopy and a four-electrode Swagelok cell. This study differentiates the working mechanisms of PAN/S composites from conventional elemental sulphur/carbon composite and also sheds light on factors that could be responsible for capacity fading in the case of PAN/S composites.

DC and small-signal physical models for the AlGaAs/GaAs high electron mobility transistor

NASA Technical Reports Server (NTRS)

Sarker, J. C.; Purviance, J. E.

1991-01-01

Analytical and numerical models are developed for the microwave small-signal performance, such as transconductance, gate-to-source capacitance, current gain cut-off frequency and the optimum cut-off frequency of the AlGaAs/GaAs High Electron Mobility Transistor (HEMT), in both normal and compressed transconductance regions. The validated I-V characteristics and the small-signal performances of four HeMT's are presented.

Comparison of serum, EDTA plasma and P100 plasma for luminex-based biomarker multiplex assays in patients with chronic obstructive pulmonary disease in the SPIROMICS study.

PubMed

O'Neal, Wanda K; Anderson, Wayne; Basta, Patricia V; Carretta, Elizabeth E; Doerschuk, Claire M; Barr, R Graham; Bleecker, Eugene R; Christenson, Stephanie A; Curtis, Jeffrey L; Han, Meilan K; Hansel, Nadia N; Kanner, Richard E; Kleerup, Eric C; Martinez, Fernando J; Miller, Bruce E; Peters, Stephen P; Rennard, Stephen I; Scholand, Mary Beth; Tal-Singer, Ruth; Woodruff, Prescott G; Couper, David J; Davis, Sonia M

2014-01-08

As a part of the longitudinal Chronic Obstructive Pulmonary Disease (COPD) study, Subpopulations and Intermediate Outcome Measures in COPD study (SPIROMICS), blood samples are being collected from 3200 subjects with the goal of identifying blood biomarkers for sub-phenotyping patients and predicting disease progression. To determine the most reliable sample type for measuring specific blood analytes in the cohort, a pilot study was performed from a subset of 24 subjects comparing serum, Ethylenediaminetetraacetic acid (EDTA) plasma, and EDTA plasma with proteinase inhibitors (P100). 105 analytes, chosen for potential relevance to COPD, arranged in 12 multiplex and one simplex platform (Myriad-RBM) were evaluated in duplicate from the three sample types from 24 subjects. The reliability coefficient and the coefficient of variation (CV) were calculated. The performance of each analyte and mean analyte levels were evaluated across sample types. 20% of analytes were not consistently detectable in any sample type. Higher reliability and/or smaller CV were determined for 12 analytes in EDTA plasma compared to serum, and for 11 analytes in serum compared to EDTA plasma. While reliability measures were similar for EDTA plasma and P100 plasma for a majority of analytes, CV was modestly increased in P100 plasma for eight analytes. Each analyte within a multiplex produced independent measurement characteristics, complicating selection of sample type for individual multiplexes. There were notable detectability and measurability differences between serum and plasma. Multiplexing may not be ideal if large reliability differences exist across analytes measured within the multiplex, especially if values differ based on sample type. For some analytes, the large CV should be considered during experimental design, and the use of duplicate and/or triplicate samples may be necessary. These results should prove useful for studies evaluating selection of samples for evaluation of potential blood biomarkers.

Comparison of serum, EDTA plasma and P100 plasma for luminex-based biomarker multiplex assays in patients with chronic obstructive pulmonary disease in the SPIROMICS study

PubMed Central

2014-01-01

Background As a part of the longitudinal Chronic Obstructive Pulmonary Disease (COPD) study, Subpopulations and Intermediate Outcome Measures in COPD study (SPIROMICS), blood samples are being collected from 3200 subjects with the goal of identifying blood biomarkers for sub-phenotyping patients and predicting disease progression. To determine the most reliable sample type for measuring specific blood analytes in the cohort, a pilot study was performed from a subset of 24 subjects comparing serum, Ethylenediaminetetraacetic acid (EDTA) plasma, and EDTA plasma with proteinase inhibitors (P100™). Methods 105 analytes, chosen for potential relevance to COPD, arranged in 12 multiplex and one simplex platform (Myriad-RBM) were evaluated in duplicate from the three sample types from 24 subjects. The reliability coefficient and the coefficient of variation (CV) were calculated. The performance of each analyte and mean analyte levels were evaluated across sample types. Results 20% of analytes were not consistently detectable in any sample type. Higher reliability and/or smaller CV were determined for 12 analytes in EDTA plasma compared to serum, and for 11 analytes in serum compared to EDTA plasma. While reliability measures were similar for EDTA plasma and P100 plasma for a majority of analytes, CV was modestly increased in P100 plasma for eight analytes. Each analyte within a multiplex produced independent measurement characteristics, complicating selection of sample type for individual multiplexes. Conclusions There were notable detectability and measurability differences between serum and plasma. Multiplexing may not be ideal if large reliability differences exist across analytes measured within the multiplex, especially if values differ based on sample type. For some analytes, the large CV should be considered during experimental design, and the use of duplicate and/or triplicate samples may be necessary. These results should prove useful for studies evaluating selection of samples for evaluation of potential blood biomarkers. PMID:24397870

Body fluid analysis: clinical utility and applicability of published studies to guide interpretation of today's laboratory testing in serous fluids.

PubMed

Block, Darci R; Algeciras-Schimnich, Alicia

2013-01-01

Requests for testing various analytes in serous fluids (e.g., pleural, peritoneal, pericardial effusions) are submitted daily to clinical laboratories. Testing of these fluids deviates from assay manufacturers' specifications, as most laboratory assays are optimized for testing blood or urine specimens. These requests add a burden to clinical laboratories, which need to validate assay performance characteristics in these fluids to exclude matrix interferences (given the different composition of body fluids) while maintaining regulatory compliance. Body fluid testing for a number of analytes has been reported in the literature; however, understanding the clinical utility of these analytes is critical because laboratories must address the analytic and clinical validation requirements, while educating clinicians on proper test utilization. In this article, we review the published data to evaluate the clinical utility of testing for numerous analytes in body fluid specimens. We also highlight the pre-analytic and analytic variables that need to be considered when reviewing published studies in body fluid testing. Finally, we provide guidance on how published studies might (or might not) guide interpretation of test results in today's clinical laboratories.

MALDI-TOF MS identification of anaerobic bacteria: assessment of pre-analytical variables and specimen preparation techniques.

PubMed

Hsu, Yen-Michael S; Burnham, Carey-Ann D

2014-06-01

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has emerged as a tool for identifying clinically relevant anaerobes. We evaluated the analytical performance characteristics of the Bruker Microflex with Biotyper 3.0 software system for identification of anaerobes and examined the impact of direct formic acid (FA) treatment and other pre-analytical factors on MALDI-TOF MS performance. A collection of 101 anaerobic bacteria were evaluated, including Clostridium spp., Propionibacterium spp., Fusobacterium spp., Bacteroides spp., and other anaerobic bacterial of clinical relevance. The results of our study indicate that an on-target extraction with 100% FA improves the rate of accurate identification without introducing misidentification (P<0.05). In addition, we modify the reporting cutoffs for the Biotyper "score" yielding acceptable identification. We found that a score of ≥1.700 can maximize the rate of identification. Of interest, MALDI-TOF MS can correctly identify anaerobes grown in suboptimal conditions, such as on selective culture media and following oxygen exposure. In conclusion, we report on a number of simple and cost-effective pre- and post-analytical modifications could enhance MALDI-TOF MS identification for anaerobic bacteria. Copyright © 2014 Elsevier Inc. All rights reserved.

Investigation of crew restraint system biomechanics. Report for May 79-Mar 81

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

Phillips, N.S.; Thomson, R.A.; Fiscus, I.B.

1982-05-01

Experimental data were collected and analyses were performed to study the influence of the dynamic mechanical properties of restraint system components on human response to impact and restraint system haulback. Tests were accomplished to isolate the characteristics of the restraint system and the human body. Three restraint webbing materials were studied at varied strain rates. A pyrotechnically powered inertia reel was tested, but could not be analytically modeled successfully. Analytical models of the human and restraint system were used to study the influence of restraint material properties changes on human response parameters. An analytical model of a rhesus monkey wasmore » also used to study the efficacy of animal tests and scaling techniques to evaluate restraint systems for human use applications.« less

An analytic model for limiting high density LH transition by the onset of the tertiary instability

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

Singh, Raghvendra, E-mail: rsingh129@gmail.com; Jhang, Hogun; Kaang, Helen H.

2016-07-15

We perform an analytic study of the tertiary instability driven by a strong excitation of zonal flows during high density low to high (LH) mode transition. The drift resistive ballooning mode is assumed to be a dominant edge turbulence driver. The analysis reproduces main qualitative features of early computational results [Rogers and Drake, Phys. Rev. Lett. 81, 4396 (1998); Guzdar et al., Phys. Plasmas 14, 020701 (2007)], as well as new characteristics of the maximum edge density due to the onset of the tertiary instability. An analytical scaling indicates that the density scaling of LH transition power may be determinedmore » by the onset condition of the tertiary instability when the operating density approaches to the Greenwald density.« less

On analytic design of loudspeaker arrays with uniform radiation characteristics

PubMed

Aarts; Janssen

2000-01-01

Some notes on analytical derived loudspeaker arrays with uniform radiation characteristics are presented. The array coefficients are derived via analytical means and compared with so-called maximal flat sequences known from telecommunications and information theory. It appears that the newly derived array, i.e., the quadratic phase array, has a higher efficiency than the Bessel array and a flatter response than the Barker array. The method discussed admits generalization to the design of arrays with desired nonuniform radiating characteristics.

An analysis of an optimal selection process for characteristics and technical performance of baseball pitchers.

PubMed

Lin, Wen-Bin; Tung, I-Wu; Chen, Mei-Jung; Chen, Mei-Yen

2011-08-01

Selection of a qualified pitcher has relied previously on qualitative indices; here, both quantitative and qualitative indices including pitching statistics, defense, mental skills, experience, and managers' recognition were collected, and an analytic hierarchy process was used to rank baseball pitchers. The participants were 8 experts who ranked characteristics and statistics of 15 baseball pitchers who comprised the first round of potential representatives for the Chinese Taipei National Baseball team. The results indicated a selection rate that was 91% consistent with the official national team roster, as 11 pitchers with the highest scores who were recommended as optimal choices to be official members of the Chinese Tai-pei National Baseball team actually participated in the 2009 Baseball World Cup. An analytic hierarchy can aid in selection of qualified pitchers, depending on situational and practical needs; the method could be extended to other sports and team-selection situations.

Exploring the Short-Channel Characteristics of Asymmetric Junctionless Double-Gate Silicon-on-Nothing MOSFET

NASA Astrophysics Data System (ADS)

Saha, Priyanka; Banerjee, Pritha; Dash, Dinesh Kumar; Sarkar, Subir Kumar

2018-03-01

This paper presents an analytical model of an asymmetric junctionless double-gate (asymmetric DGJL) silicon-on-nothing metal-oxide-semiconductor field-effect transistor (MOSFET). Solving the 2-D Poisson's equation, the expressions for center potential and threshold voltage are calculated. In addition, the response of the device toward the various short-channel effects like hot carrier effect, drain-induced barrier lowering and threshold voltage roll-off has also been examined along with subthreshold swing and drain current characteristics. Performance analysis of the present model is also demonstrated by comparing its short-channel behavior with conventional DGJL MOSFET. The effect of variation of the device features due to the variation of device parameters is also studied. The simulated results obtained using 2D device simulator, namely ATLAS, are in good agreement with the analytical results, hence validating our derived model.

Validation of the LacTek test applied to spiked extracts of tissue samples: determination of performance characteristics.

PubMed

Mitchell, J M; Yee, A J; McNab, W B; Griffiths, M W; McEwen, S A

1999-01-01

LacTek tests are competitive enzyme-linked immunosorbent assays intended for rapid detection of antimicrobial residues in bovine milk. In this study, the LacTek test protocol was modified for use with extracts of bovine tissue to detect beta-lactam, tetracycline, and sulfamethazine residues. Test performance characteristics--precision, accuracy, ruggedness, practicability, and analytical specificity and sensitivity--were investigated. Results suggest that LacTek tests can be easily adapted to detect antimicrobial residues in extracts of lean ground beef. However, positive samples may not contain residues at violative concentrations (i.e., Canadian maximum residue limits), and therefore, additional analysis would be required for final confirmation and quantitation (e.g., chromatography).

Analytical approach for modeling and performance analysis of microring resonators as optical filters with multiple output bus waveguides

NASA Astrophysics Data System (ADS)

Lakra, Suchita; Mandal, Sanjoy

2017-06-01

A quadruple micro-optical ring resonator (QMORR) with multiple output bus waveguides is mathematically modeled and analyzed by making use of the delay-line signal processing approach in Z-domain and Mason's gain formula. The performances of QMORR with two output bus waveguides with vertical coupling are analyzed. This proposed structure is capable of providing wider free spectral response from both the output buses with appreciable cross talk. Thus, this configuration could provide increased capacity to insert a large number of communication channels. The simulated frequency response characteristic and its dispersion and group delay characteristics are graphically presented using the MATLAB environment.

Calculation of characteristics of compressed gaseous xenon gamma-ray detectors

NASA Astrophysics Data System (ADS)

Komarov, V. B.; Dmitrenko, V. V.; Ulin, S. E.; Uteshev, Z. M.

1992-12-01

Energy resolution and pulse distribution of a compressed gaseous xenon cylindrical detector were calculated. The analytical calculation took into account gamma-ray energy, fluctuation of electron-ion pairs, electron distribution, recombination, and H excess. The calculation was performed for a xenon density less than 0.6 g/cm and H excess less than 2 percent.

Theoretical Combustion Performance of Several High-Energy Fuels for Ramjet Engines

NASA Technical Reports Server (NTRS)

Tower, Leonard K; Breitwieser, Roland; Gammon, Benson E

1958-01-01

An analytical evaluation of the air and fuel specific-impulse characteristics of magnesium, magnesium octene-1 slurries, aluminum, aluminum octene-1 slurries, boron, boron octene-1 slurries, carbon, hydrogen, alpha-methylnaphthalene, diborane, pentaborane, and octene-1 is presented. While chemical equilibrium was assumed in the combustion process, the expansion was assumed to occur at fixed composition.

Sensory perception. [role of human vestibular system in dynamic space perception and manual vehicle control

NASA Technical Reports Server (NTRS)

1974-01-01

The effect of motion on the ability of men to perform a variety of control actions was investigated. Special attention was given to experimental and analytical studies of the dynamic characteristics of the otoliths and semicircular canals using a two axis angular motion simulator and a one axis linear motion simulator.

A Factor-Analytic Investigation of Role Types and Profiles of Higher Education Department Chairs.

ERIC Educational Resources Information Center

Carroll, James B.; Gmelch, Walter H.

This paper reports on a study that investigated the role, attitudes, and behaviors of department chairs in higher education. Specifically, the study investigated four objectives: (1) to examine role factors of effective chair performance; (2) to assess the impact of antecedent variables such as individual characteristics (gender, marital status,…

The performance characteristics of lateral flow devices with 2 strains of highly pathogenic avian influenza virus

USDA-ARS?s Scientific Manuscript database

Lateral flow devices (LFD) are commercially available and provide a fast, highly specific, on-site test for avian influenza. Because of the low analytic sensitivity of LFD tests at low virus concentrations, targeted sampling of sick and dead birds has been proposed in order to increase detection pr...

Comparison of theoretically predicted lateral-directional aerodynamic characteristics with full-scale wind tunnel data on the ATLIT airplane

NASA Technical Reports Server (NTRS)

Griswold, M.; Roskam, J.

1980-01-01

An analytical method is presented for predicting lateral-directional aerodynamic characteristics of light twin engine propeller-driven airplanes. This method is applied to the Advanced Technology Light Twin Engine airplane. The calculated characteristics are correlated against full-scale wind tunnel data. The method predicts the sideslip derivatives fairly well, although angle of attack variations are not well predicted. Spoiler performance was predicted somewhat high but was still reasonable. The rudder derivatives were not well predicted, in particular the effect of angle of attack. The predicted dynamic derivatives could not be correlated due to lack of experimental data.

Performance characteristics of bio-inspired metal nanostructures as surface-enhanced Raman scattered (SERS) substrates

DOE PAGES

Areizaga-Martinez, Hector I.; Kravchenko, Ivan; Lavrik, Nickolay V.; ...

2016-08-26

The fabrication of high-performance plasmonic nanomaterials for bio-sensing and trace chemical detection is a field of intense theoretical and experimental research. The use of metal-silicon nanopillar arrays as analytical sensors has been reported with reasonable results in recent years. The use of bio-inspired nanocomposite structures that follow the Fibonacci numerical architecture offers the opportunity to develop nanostructures with theoretically higher and more reproducible plasmonic fields over extended areas. The work presented here describes the nanofabrication process for a series of 40 µm × 40 µm bio-inspired arrays classified as asymmetric fractals (sunflower seeds and romanesco broccoli), bilaterally symmetric (acacia leavesmore » and honeycombs), and radially symmetric (such as orchids and lily flowers) using electron beam lithography. In addition, analytical capabilities were evaluated using surface-enhanced Raman scattering (SERS). Here, the substrate characterization and SERS performance of the developed substrates as the strategies to assess the design performance are presented and discussed.« less

Performance characteristics of bio-inspired metal nanostructures as surface-enhanced Raman scattered (SERS) substrates

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

Areizaga-Martinez, Hector I.; Kravchenko, Ivan; Lavrik, Nickolay V.

The fabrication of high-performance plasmonic nanomaterials for bio-sensing and trace chemical detection is a field of intense theoretical and experimental research. The use of metal-silicon nanopillar arrays as analytical sensors has been reported with reasonable results in recent years. The use of bio-inspired nanocomposite structures that follow the Fibonacci numerical architecture offers the opportunity to develop nanostructures with theoretically higher and more reproducible plasmonic fields over extended areas. The work presented here describes the nanofabrication process for a series of 40 µm × 40 µm bio-inspired arrays classified as asymmetric fractals (sunflower seeds and romanesco broccoli), bilaterally symmetric (acacia leavesmore » and honeycombs), and radially symmetric (such as orchids and lily flowers) using electron beam lithography. In addition, analytical capabilities were evaluated using surface-enhanced Raman scattering (SERS). Here, the substrate characterization and SERS performance of the developed substrates as the strategies to assess the design performance are presented and discussed.« less

Performance Characteristics of Bio-Inspired Metal Nanostructures as Surface-Enhanced Raman Scattered (SERS) Substrates.

PubMed

Areizaga-Martinez, Hector I; Kravchenko, Ivan; Lavrik, Nickolay V; Sepaniak, Michael J; Hernández-Rivera, Samuel P; De Jesús, Marco A

2016-09-01

The fabrication of high-performance plasmonic nanomaterials for bio-sensing and trace chemical detection is a field of intense theoretical and experimental research. The use of metal-silicon nanopillar arrays as analytical sensors has been reported with reasonable results in recent years. The use of bio-inspired nanocomposite structures that follow the Fibonacci numerical architecture offers the opportunity to develop nanostructures with theoretically higher and more reproducible plasmonic fields over extended areas. The work presented here describes the nanofabrication process for a series of 40 µm × 40 µm bio-inspired arrays classified as asymmetric fractals (sunflower seeds and romanesco broccoli), bilaterally symmetric (acacia leaves and honeycombs), and radially symmetric (such as orchids and lily flowers) using electron beam lithography. In addition, analytical capabilities were evaluated using surface-enhanced Raman scattering (SERS). The substrate characterization and SERS performance of the developed substrates as the strategies to assess the design performance are presented and discussed. © The Author(s) 2016.

Detonation Performance Analyses for Recent Energetic Molecules

NASA Astrophysics Data System (ADS)

Stiel, Leonard; Samuels, Philip; Spangler, Kimberly; Iwaniuk, Daniel; Cornell, Rodger; Baker, Ernest

2017-06-01

Detonation performance analyses were conducted for a number of evolving and potential high explosive materials. The calculations were completed for theoretical maximum densities of the explosives using the Jaguar thermo-chemical equation of state computer programs for performance evaluations and JWL/JWLB equations of state parameterizations. A number of recently synthesized materials were investigated for performance characterizations and comparisons to existing explosives, including TNT, RDX, HMX, and Cl-20. The analytic cylinder model was utilized to establish cylinder and Gurney velocities as functions of the radial expansions of the cylinder for each explosive. The densities and heats of formulation utilized in the calculations are primarily experimental values from Picatinny Arsenal and other sources. Several of the new materials considered were predicted to have enhanced detonation characteristics compared to conventional explosives. In order to confirm the accuracy of the Jaguar and analytic cylinder model results, available experimental detonation and Gurney velocities for representative energetic molecules and their formulations were compared with the corresponding calculated values. Close agreement was obtained with most of the data. Presently at NATO.

Development of Multiobjective Optimization Techniques for Sonic Boom Minimization

NASA Technical Reports Server (NTRS)

Chattopadhyay, Aditi; Rajadas, John Narayan; Pagaldipti, Naryanan S.

1996-01-01

A discrete, semi-analytical sensitivity analysis procedure has been developed for calculating aerodynamic design sensitivities. The sensitivities of the flow variables and the grid coordinates are numerically calculated using direct differentiation of the respective discretized governing equations. The sensitivity analysis techniques are adapted within a parabolized Navier Stokes equations solver. Aerodynamic design sensitivities for high speed wing-body configurations are calculated using the semi-analytical sensitivity analysis procedures. Representative results obtained compare well with those obtained using the finite difference approach and establish the computational efficiency and accuracy of the semi-analytical procedures. Multidisciplinary design optimization procedures have been developed for aerospace applications namely, gas turbine blades and high speed wing-body configurations. In complex applications, the coupled optimization problems are decomposed into sublevels using multilevel decomposition techniques. In cases with multiple objective functions, formal multiobjective formulation such as the Kreisselmeier-Steinhauser function approach and the modified global criteria approach have been used. Nonlinear programming techniques for continuous design variables and a hybrid optimization technique, based on a simulated annealing algorithm, for discrete design variables have been used for solving the optimization problems. The optimization procedure for gas turbine blades improves the aerodynamic and heat transfer characteristics of the blades. The two-dimensional, blade-to-blade aerodynamic analysis is performed using a panel code. The blade heat transfer analysis is performed using an in-house developed finite element procedure. The optimization procedure yields blade shapes with significantly improved velocity and temperature distributions. The multidisciplinary design optimization procedures for high speed wing-body configurations simultaneously improve the aerodynamic, the sonic boom and the structural characteristics of the aircraft. The flow solution is obtained using a comprehensive parabolized Navier Stokes solver. Sonic boom analysis is performed using an extrapolation procedure. The aircraft wing load carrying member is modeled as either an isotropic or a composite box beam. The isotropic box beam is analyzed using thin wall theory. The composite box beam is analyzed using a finite element procedure. The developed optimization procedures yield significant improvements in all the performance criteria and provide interesting design trade-offs. The semi-analytical sensitivity analysis techniques offer significant computational savings and allow the use of comprehensive analysis procedures within design optimization studies.

Analytical performance, agreement and user-friendliness of six point-of-care testing urine analysers for urinary tract infection in general practice

PubMed Central

Schot, Marjolein J C; van Delft, Sanne; Kooijman-Buiting, Antoinette M J; de Wit, Niek J; Hopstaken, Rogier M

2015-01-01

Objective Various point-of-care testing (POCT) urine analysers are commercially available for routine urine analysis in general practice. The present study compares analytical performance, agreement and user-friendliness of six different POCT urine analysers for diagnosing urinary tract infection in general practice. Setting All testing procedures were performed at a diagnostic centre for primary care in the Netherlands. Urine samples were collected at four general practices. Primary and secondary outcome measures Analytical performance and agreement of the POCT analysers regarding nitrite, leucocytes and erythrocytes, with the laboratory reference standard, was the primary outcome measure, and analysed by calculating sensitivity, specificity, positive and negative predictive value, and Cohen's κ coefficient for agreement. Secondary outcome measures were the user-friendliness of the POCT analysers, in addition to other characteristics of the analysers. Results The following six POCT analysers were evaluated: Uryxxon Relax (Macherey Nagel), Urisys 1100 (Roche), Clinitek Status (Siemens), Aution 11 (Menarini), Aution Micro (Menarini) and Urilyzer (Analyticon). Analytical performance was good for all analysers. Compared with laboratory reference standards, overall agreement was good, but differed per parameter and per analyser. Concerning the nitrite test, the most important test for clinical practice, all but one showed perfect agreement with the laboratory standard. For leucocytes and erythrocytes specificity was high, but sensitivity was considerably lower. Agreement for leucocytes varied between good to very good, and for the erythrocyte test between fair and good. First-time users indicated that the analysers were easy to use. They expected higher productivity and accuracy when using these analysers in daily practice. Conclusions The overall performance and user-friendliness of all six commercially available POCT urine analysers was sufficient to justify routine use in suspected urinary tract infections in general practice. PMID:25986635

Analysis and test of a 16-foot radial rib reflector developmental model

NASA Technical Reports Server (NTRS)

Birchenough, Shawn A.

1989-01-01

Analytical and experimental modal tests were performed to determine the vibrational characteristics of a 16-foot diameter radial rib reflector model. Single rib analyses and experimental tests provided preliminary information relating to the reflector. A finite element model predicted mode shapes and frequencies of the reflector. The analyses correlated well with the experimental tests, verifying the modeling method used. The results indicate that five related, characteristic mode shapes form a group. The frequencies of the modes are determined by the relative phase of the radial ribs.

Experimental study of the operating characteristics of premixing-prevaporizing fuel/air mixing passages

NASA Technical Reports Server (NTRS)

Rohy, D. A.; Meier, J. G.

1983-01-01

Fuel spray and air flow characteristics were determined using nonintrusive (optical) measurement techniques in a fuel preparation duct. A very detailed data set was obtained at high pressures (to 10 atm) and temperatures (to 750 K). The data will be used to calibrate an analytical model which will facilitate the design of a lean premixed prevaporized combustor. This combustor has potential for achieving low pollutant emissions and low levels of flame radiation and pattern factors conductive to improved durability and performance for a variety of fuels.

Association of Individual Characteristics with Teleoperation Performance.

PubMed

Pan, Dan; Zhang, Yijing; Li, Zhizhong; Tian, Zhiqiang

2016-09-01

A number of space activities (e.g., extravehicular astronaut rescue, cooperation in satellite services, space station supplies, and assembly) are implemented directly or assisted by remote robotic arms. Our study aimed to reveal those individual characteristics which could positively influence or even predict teleoperation performance of such a space robotic arm. There were 64 male volunteers without robot operation experience recruited for the study. Their individual characteristics were assessed, including spatial cognitive ability, cognitive style, and personality traits. The experimental tasks were three abstracted teleoperation tasks of a simulated space robotic arm: point aiming, line alignment, and obstacle avoidance. Teleoperation performance was measured from two aspects: task performance (completion time, extra distance moved, operation slips) and safety performance (collisions, joint limitations reached). The Pearson coefficients between individual characteristics and teleoperation performance were examined along with performance prediction models. It was found that the subjects with relatively high mental rotation ability or low neuroticism had both better task and safety performance (|r| = 0.212 ∼ 0.381). Subjects with relatively high perspective taking ability or high agreeableness had better task performance (r = -0.253; r = -0.249). Imagery subjects performed better than verbal subjects regarding both task and safety performance (|r| = 0.236 ∼ 0.290). Compared with analytic subjects, wholist subjects had better safety performance (r = 0.300). Additionally, extraverted subjects had better task performance (r = -0.259), but worse safety performance (r = 0.230). Those with high spatial cognitive ability, imagery and wholist cognitive style, low neuroticism, and high agreeableness were seen to have more advantages in working with the remote robotic arm. These results could be helpful to astronaut selection and training for space station missions. Pan D, Zhang Y, Li Z, Tian Z. Association of individual characteristics with teleoperation performance. Aerosp Med Hum Perform. 2016; 87(9):772-780.

Theoretical performance of cross-wind axis turbines with results for a catenary vertical axis configuration

NASA Technical Reports Server (NTRS)

Muraca, R. J.; Stephens, M. V.; Dagenhart, J. R.

1975-01-01

A general analysis capable of predicting performance characteristics of cross-wind axis turbines was developed, including the effects of airfoil geometry, support struts, blade aspect ratio, windmill solidity, blade interference and curved flow. The results were compared with available wind tunnel results for a catenary blade shape. A theoretical performance curve for an aerodynamically efficient straight blade configuration was also presented. In addition, a linearized analytical solution applicable for straight configurations was developed. A listing of the computer program developed for numerical solutions of the general performance equations is included in the appendix.

Scanners for analytic print measurement: the devil in the details

NASA Astrophysics Data System (ADS)

Zeise, Eric K.; Williams, Don; Burns, Peter D.; Kress, William C.

2007-01-01

Inexpensive and easy-to-use linear and area-array scanners have frequently substituted as colorimeters and densitometers for low-frequency (i.e., large area) hard copy image measurement. Increasingly, scanners are also being used for high spatial frequency, image microstructure measurements, which were previously reserved for high performance microdensitometers. In this paper we address characteristics of flatbed reflection scanners in the evaluation of print uniformity, geometric distortion, geometric repeatability and the influence of scanner MTF and noise on analytic measurements. Suggestions are made for the specification and evaluation of scanners to be used in print image quality standards that are being developed.

Analysis of SRM model nozzle calibration test data in support of IA12B, IA12C and IA36 space shuttle launch vehicle aerodynamics tests

NASA Technical Reports Server (NTRS)

Baker, L. R., Jr.; Tevepaugh, J. A.; Penny, M. M.

1973-01-01

Variations of nozzle performance characteristics of the model nozzles used in the Space Shuttle IA12B, IA12C, IA36 power-on launch vehicle test series are shown by comparison between experimental and analytical data. The experimental data are nozzle wall pressure distributions and schlieren photographs of the exhaust plume shapes. The exhaust plume shapes were simulated experimentally with cold flow while the analytical data were generated using a method-of-characteristics solution. Exhaust plume boundaries, boundary shockwave locations and nozzle wall pressure measurements calculated analytically agree favorably with the experimental data from the IA12C and IA36 test series. For the IA12B test series condensation was suspected in the exhaust plumes at the higher pressure ratios required to simulate the prototype plume shapes. Nozzle calibration tests for the series were conducted at pressure ratios where condensation either did not occur or if present did not produce a noticeable effect on the plume shapes. However, at the pressure ratios required in the power-on launch vehicle tests condensation probably occurs and could significantly affect the exhaust plume shapes.

Decision-analytic modeling studies: An overview for clinicians using multiple myeloma as an example.

PubMed

Rochau, U; Jahn, B; Qerimi, V; Burger, E A; Kurzthaler, C; Kluibenschaedl, M; Willenbacher, E; Gastl, G; Willenbacher, W; Siebert, U

2015-05-01

The purpose of this study was to provide a clinician-friendly overview of decision-analytic models evaluating different treatment strategies for multiple myeloma (MM). We performed a systematic literature search to identify studies evaluating MM treatment strategies using mathematical decision-analytic models. We included studies that were published as full-text articles in English, and assessed relevant clinical endpoints, and summarized methodological characteristics (e.g., modeling approaches, simulation techniques, health outcomes, perspectives). Eleven decision-analytic modeling studies met our inclusion criteria. Five different modeling approaches were adopted: decision-tree modeling, Markov state-transition modeling, discrete event simulation, partitioned-survival analysis and area-under-the-curve modeling. Health outcomes included survival, number-needed-to-treat, life expectancy, and quality-adjusted life years. Evaluated treatment strategies included novel agent-based combination therapies, stem cell transplantation and supportive measures. Overall, our review provides a comprehensive summary of modeling studies assessing treatment of MM and highlights decision-analytic modeling as an important tool for health policy decision making. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Revisiting the positive DC corona discharge theory: Beyond Peek's and Townsend's law

NASA Astrophysics Data System (ADS)

Monrolin, Nicolas; Praud, Olivier; Plouraboué, Franck

2018-06-01

The classical positive Corona Discharge theory in a cylindrical axisymmetric configuration is revisited in order to find analytically the influence of gas properties and thermodynamic conditions on the corona current. The matched asymptotic expansion of Durbin and Turyn [J. Phys. D: Appl. Phys. 20, 1490-1495 (1987)] of a simplified but self-consistent problem is performed and explicit analytical solutions are derived. The mathematical derivation enables us to express a new positive DC corona current-voltage characteristic, choosing either a dimensionless or dimensional formulation. In dimensional variables, the current voltage law and the corona inception voltage explicitly depend on the electrode size and physical gas properties such as ionization and photoionization parameters. The analytical predictions are successfully confronted with experiments and Peek's and Townsend's laws. An analytical expression of the corona inception voltage φ o n is proposed, which depends on the known values of physical parameters without adjustable parameters. As a proof of consistency, the classical Townsend current-voltage law I = C φ ( φ - φ o n ) is retrieved by linearizing the non-dimensional analytical solution. A brief parametric study showcases the interest in this analytical current model, especially for exploring small corona wires or considering various thermodynamic conditions.

New airfoil sections for straight bladed turbine

NASA Astrophysics Data System (ADS)

Boumaza, B.

1987-07-01

A theoretical investigation of aerodynamic performance for vertical axis Darrieus wind turbine with new airfoils sections is carried out. The blade section aerodynamics characteristics are determined from turbomachines cascade model. The model is also adapted to the vertical Darrieus turbine for the performance prediction of the machine. In order to choose appropriate value of zero-lift-drag coefficient in calculation, an analytical expression is introduced as function of chord-radius ratio and Reynolds numbers. New airfoils sections are proposed and analyzed for straight-bladed turbine.

Propeller flow visualization techniques

NASA Technical Reports Server (NTRS)

Stefko, G. L.; Paulovich, F. J.; Greissing, J. P.; Walker, E. D.

1982-01-01

Propeller flow visualization techniques were tested. The actual operating blade shape as it determines the actual propeller performance and noise was established. The ability to photographically determine the advanced propeller blade tip deflections, local flow field conditions, and gain insight into aeroelastic instability is demonstrated. The analytical prediction methods which are being developed can be compared with experimental data. These comparisons contribute to the verification of these improved methods and give improved capability for designing future advanced propellers with enhanced performance and noise characteristics.

Solar cells

NASA Astrophysics Data System (ADS)

Cuquel, A.; Roussel, M.

The physical and electronic characteristics of solar cells are discussed in terms of space applications. The principles underlying the photovoltaic effect are reviewed, including an analytic model for predicting the performance of individual cells and arrays of cells. Attention is given to the effects of electromagnetic and ionizing radiation, micrometeors, thermal and mechanical stresses, pollution and degassing encountered in space. The responses of different types of solar cells to the various performance-degrading agents are examined, with emphasis on techniques for quality assurance in the manufacture and mounting of Si cells.

Research on the Environmental Performance Evaluation of Electronic Waste Reverse Logistics Enterprise

NASA Astrophysics Data System (ADS)

Yang, Yu-Xiang; Chen, Fei-Yang; Tong, Tong

According to the characteristic of e-waste reverse logistics, environmental performance evaluation system of electronic waste reverse logistics enterprise is proposed. We use fuzzy analytic hierarchy process method to evaluate the system. In addition, this paper analyzes the enterprise X, as an example, to discuss the evaluation method. It's important to point out attributes and indexes which should be strengthen during the process of ewaste reverse logistics and provide guidance suggestions to domestic e-waste reverse logistics enterprises.

Real-time simulation of an automotive gas turbine using the hybrid computer

NASA Technical Reports Server (NTRS)

Costakis, W.; Merrill, W. C.

1984-01-01

A hybrid computer simulation of an Advanced Automotive Gas Turbine Powertrain System is reported. The system consists of a gas turbine engine, an automotive drivetrain with four speed automatic transmission, and a control system. Generally, dynamic performance is simulated on the analog portion of the hybrid computer while most of the steady state performance characteristics are calculated to run faster than real time and makes this simulation a useful tool for a variety of analytical studies.

Computer program for Stirling engine performance calculations

NASA Technical Reports Server (NTRS)

Tew, R. C., Jr.

1983-01-01

The thermodynamic characteristics of the Stirling engine were analyzed and modeled on a computer to support its development as a possible alternative to the automobile spark ignition engine. The computer model is documented. The documentation includes a user's manual, symbols list, a test case, comparison of model predictions with test results, and a description of the analytical equations used in the model.

Determinants of project success

NASA Technical Reports Server (NTRS)

Murphy, D. C.; Baker, B. N.; Fisher, D.

1974-01-01

The interactions of numerous project characteristics, with particular reference to project performance, were studied. Determinants of success are identified along with the accompanying implications for client organization, parent organization, project organization, and future research. Variables are selected which are found to have the greatest impact on project outcome, and the methodology and analytic techniques to be employed in identification of those variables are discussed.

Rapid and reliable QuEChERS-based LC-MS/MS method for determination of acrylamide in potato chips and roasted coffee

NASA Astrophysics Data System (ADS)

Stefanović, S.; Đorđevic, V.; Jelušić, V.

2017-09-01

The aim of this paper is to verify the performance characteristics and fitness for purpose of rapid and simple QuEChERS-based LC-MS/MS method for determination of acrylamide in potato chips and coffee. LC-MS/MS is by far the most suitable analytical technique for acrylamide measurements given its inherent sensitivity and selectivity, as well as capability of analyzing underivatized molecule. Acrylamide in roasted coffee and potato chips wasextracted with water:acetonitrile mixture using NaCl and MgSO4. Cleanup was carried out with MgSO4 and PSA. Obtained results were satisfactory. Recoveries were in the range of 85-112%, interlaboratory reproducibility (Cv) was 5.8-7.6% and linearity (R2) was in the range of 0.995-0.999. LoQ was 35 μg kg-1 for coffee and 20 μg kg-1 for potato chips. Performance characteristic of the method are compliant with criteria for analytical methods validation. Presented method for quantitative determination of acrylamide in roasted coffee and potato chips is fit for purposes of self-control in food industry as well as regulatory controls carried out by the governmental agencies.

Zarya Energy Balance Analysis: The Effect of Spacecraft Shadowing on Solar Array Performance

NASA Technical Reports Server (NTRS)

Hoffman, David J.; Kolosov, Vladimir

1999-01-01

The first element of the International Space Station (ISS). Zarya, was funded by NASA and built by the Russian aerospace company Khrunichev State Research and Production Space Center (KhSC). NASA Glenn Research Center (GRC) and KhSC collaborated in performing analytical predictions of the on-orbit electrical performance of Zarya's solar arrays. GRC assessed the pointing characteristics of and shadow patterns on Zarya's solar arrays to determine the average solar energy incident on the arrays. KHSC used the incident energy results to determine Zarya's electrical power generation capability and orbit-average power balance. The power balance analysis was performed over a range of solar beta angles and vehicle operational conditions. This analysis enabled identification of problems that could impact the power balance for specific flights during ISS assembly and was also used as the primary means of verifying that Zarya complied with electrical power requirements. Analytical results are presented for select stages in the ISS assembly sequence along with a discussion of the impact of shadowing on the electrical performance of Zarya's solar arrays.

Acceleration of high-pressure-ratio single-spool turbojet engine as determined from component performance characteristics I : effect of air bleed at compressor outlet

NASA Technical Reports Server (NTRS)

Rebeske, John J , Jr; Rohlik, Harold E

1953-01-01

An analytical investigation was made to determine from component performance characteristics the effect of air bleed at the compressor outlet on the acceleration characteristics of a typical high-pressure-ratio single-spool turbojet engine. Consideration of several operating lines on the compressor performance map with two turbine-inlet temperatures showed that for a minimum acceleration time the turbine-inlet temperature should be the maximum allowable, and the operating line on the compressor map should be as close to the surge region as possible throughout the speed range. Operation along such a line would require a continuously varying bleed area. A relatively simple two-step area bleed gives only a small increase in acceleration time over a corresponding variable-area bleed. For the modes of operation considered, over 84 percent of the total acceleration time was required to accelerate through the low-speed range ; therefore, better low-speed compressor performance (higher pressure ratios and efficiencies) would give a significant reduction in acceleration time.

Theoretical studies of system performance and adaptive optics design parameters

NASA Astrophysics Data System (ADS)

Tyson, Robert K.

1990-08-01

The ultimate performance of an adaptive optics (AO) system can be sensitive to specific design parameters of individual components. The type and configuration of a wavefront sensor or the shape of individual deformable mirror actuator influence functions can have a profound effect on the correctability of the AO system. This paper will discuss the results of a theoretical study which employed both closed form analytic solutions and computer models. A parametric analysis of wavefront sensor characteristics, noise, and subaperture geometry are independently evaluated against system response to an aberrated wave characteristic of atmospheric turbulence. Similarly, the shape and extent of the deformable mirror influence function and the placement and number of actuators is evaluated to characterize the effects of fitting error and coupling.

The Role of Teamwork in the Analysis of Big Data: A Study of Visual Analytics and Box Office Prediction.

PubMed

Buchanan, Verica; Lu, Yafeng; McNeese, Nathan; Steptoe, Michael; Maciejewski, Ross; Cooke, Nancy

2017-03-01

Historically, domains such as business intelligence would require a single analyst to engage with data, develop a model, answer operational questions, and predict future behaviors. However, as the problems and domains become more complex, organizations are employing teams of analysts to explore and model data to generate knowledge. Furthermore, given the rapid increase in data collection, organizations are struggling to develop practices for intelligence analysis in the era of big data. Currently, a variety of machine learning and data mining techniques are available to model data and to generate insights and predictions, and developments in the field of visual analytics have focused on how to effectively link data mining algorithms with interactive visuals to enable analysts to explore, understand, and interact with data and data models. Although studies have explored the role of single analysts in the visual analytics pipeline, little work has explored the role of teamwork and visual analytics in the analysis of big data. In this article, we present an experiment integrating statistical models, visual analytics techniques, and user experiments to study the role of teamwork in predictive analytics. We frame our experiment around the analysis of social media data for box office prediction problems and compare the prediction performance of teams, groups, and individuals. Our results indicate that a team's performance is mediated by the team's characteristics such as openness of individual members to others' positions and the type of planning that goes into the team's analysis. These findings have important implications for how organizations should create teams in order to make effective use of information from their analytic models.

Prevalidation in pharmaceutical analysis. Part I. Fundamentals and critical discussion.

PubMed

Grdinić, Vladimir; Vuković, Jadranka

2004-05-28

A complete prevalidation, as a basic prevalidation strategy for quality control and standardization of analytical procedure was inaugurated. Fast and simple, the prevalidation methodology based on mathematical/statistical evaluation of a reduced number of experiments (N < or = 24) was elaborated and guidelines as well as algorithms were given in detail. This strategy has been produced for the pharmaceutical applications and dedicated to the preliminary evaluation of analytical methods where linear calibration model, which is very often occurred in practice, could be the most appropriate to fit experimental data. The requirements presented in this paper should therefore help the analyst to design and perform the minimum number of prevalidation experiments needed to obtain all the required information to evaluate and demonstrate the reliability of its analytical procedure. In complete prevalidation process, characterization of analytical groups, checking of two limiting groups, testing of data homogeneity, establishment of analytical functions, recognition of outliers, evaluation of limiting values and extraction of prevalidation parameters were included. Moreover, system of diagnosis for particular prevalidation step was suggested. As an illustrative example for demonstration of feasibility of prevalidation methodology, among great number of analytical procedures, Vis-spectrophotometric procedure for determination of tannins with Folin-Ciocalteu's phenol reagent was selected. Favourable metrological characteristics of this analytical procedure, as prevalidation figures of merit, recognized the metrological procedure as a valuable concept in preliminary evaluation of quality of analytical procedures.

The performance and application of high speed long life LH2 hybrid bearings for reusable rocket engine turbomachinery

NASA Technical Reports Server (NTRS)

Hannum, N. P.; Nielson, C. E.

1983-01-01

Data are presented for two different experimental programs which were conducted to investigate the characteristics of a hybrid (hydrostatic/ball) bearing operating in liquid hydrogen. The same bearing design was used in both programs. Analytical predictions were made of the bearing characteristics and are compared with the experimental results when possible. The first program used a bearing tester to determine the steady state, transient, and cyclic life characteristics of the bearing over a wide range of operating conditions. The second program demonstrated the feasibility of applying hybrid bearings to an actual high speed turbopump by retrofitting and then testing an existing liquid hydrogen turbopump with the bearings.

A study of methods to predict and measure the transmission of sound through the walls of light aircraft. Integration of certain singular boundary element integrals for applications in linear acoustics

NASA Technical Reports Server (NTRS)

Zimmerle, D.; Bernhard, R. J.

1985-01-01

An alternative method for performing singular boundary element integrals for applications in linear acoustics is discussed. The method separates the integral of the characteristic solution into a singular and nonsingular part. The singular portion is integrated with a combination of analytic and numerical techniques while the nonsingular portion is integrated with standard Gaussian quadrature. The method may be generalized to many types of subparametric elements. The integrals over elements containing the root node are considered, and the characteristic solution for linear acoustic problems are examined. The method may be generalized to most characteristic solutions.

Design Investigation on Applicable Mesh Structures for Medical Stent Applications

NASA Astrophysics Data System (ADS)

Asano, Shoji; He, Jianmei

2017-11-01

In recent years, utilization of medical stents is one of effective treatments for stenosis and occlusion occurring in a living body’s lumen indispensable for maintenance of human life such as superficial femoral artery (SFA) occlusion. However, there are concerns about the occurrence of fatigue fractures caused by stress concentrations, neointimal hyperplasia and the like due to the shape structure and the manufacturing method in the conventional stents, and a stent having high strength and high flexibility is required. Therefore, in this research, applicable mesh structures for medical stents based on the design concepts of high strength, high flexibility are interested to solve various problem of conventional stent. According to the shape and dimensions of SFA occlusion therapy stent and indwelling delivery catheter, shape design of the meshed stent are performed using 3-dimensional CAD software Solid Works first. Then analytical examination on storage characteristics and compression characteristics of such mesh structure applied stent models were carried out through finite element analysis software ANSYS Workbench. Meshed stent models with higher strength and higher flexibility with integral molding are investigated analytically. It was found that the storage characteristics and compression characteristics of meshed stent modles are highly dependent on the basic mesh shapes with same surface void ratio. Trade-off relationship between flexibility and storage characteristics is found exited, it is required to provide appropriate curvatures during basic mesh shape design.

Permeation absorption sampler with multiple detection

DOEpatents

Zaromb, Solomon

1990-01-01

A system for detecting analytes in air or aqueous systems includes a permeation absorption preconcentrator sampler for the analytes and analyte detectors. The preconcentrator has an inner fluid-permeable container into which a charge of analyte-sorbing liquid is intermittently injected, and a fluid-impermeable outer container. The sample is passed through the outer container and around the inner container for trapping and preconcentrating the analyte in the sorbing liquid. The analyte can be detected photometrically by injecting with the sorbing material a reagent which reacts with the analyte to produce a characteristic color or fluorescence which is detected by illuminating the contents of the inner container with a light source and measuring the absorbed or emitted light, or by producing a characteristic chemiluminescence which can be detected by a suitable light sensor. The analyte can also be detected amperometrically. Multiple inner containers may be provided into which a plurality of sorbing liquids are respectively introduced for simultaneously detecting different analytes. Baffles may be provided in the outer container. A calibration technique is disclosed.

Performance Models for the Spike Banded Linear System Solver

DOE PAGES

Manguoglu, Murat; Saied, Faisal; Sameh, Ahmed; ...

2011-01-01

With availability of large-scale parallel platforms comprised of tens-of-thousands of processors and beyond, there is significant impetus for the development of scalable parallel sparse linear system solvers and preconditioners. An integral part of this design process is the development of performance models capable of predicting performance and providing accurate cost models for the solvers and preconditioners. There has been some work in the past on characterizing performance of the iterative solvers themselves. In this paper, we investigate the problem of characterizing performance and scalability of banded preconditioners. Recent work has demonstrated the superior convergence properties and robustness of banded preconditioners,more » compared to state-of-the-art ILU family of preconditioners as well as algebraic multigrid preconditioners. Furthermore, when used in conjunction with efficient banded solvers, banded preconditioners are capable of significantly faster time-to-solution. Our banded solver, the Truncated Spike algorithm is specifically designed for parallel performance and tolerance to deep memory hierarchies. Its regular structure is also highly amenable to accurate performance characterization. Using these characteristics, we derive the following results in this paper: (i) we develop parallel formulations of the Truncated Spike solver, (ii) we develop a highly accurate pseudo-analytical parallel performance model for our solver, (iii) we show excellent predication capabilities of our model – based on which we argue the high scalability of our solver. Our pseudo-analytical performance model is based on analytical performance characterization of each phase of our solver. These analytical models are then parameterized using actual runtime information on target platforms. An important consequence of our performance models is that they reveal underlying performance bottlenecks in both serial and parallel formulations. All of our results are validated on diverse heterogeneous multiclusters – platforms for which performance prediction is particularly challenging. Finally, we provide predict the scalability of the Spike algorithm using up to 65,536 cores with our model. In this paper we extend the results presented in the Ninth International Symposium on Parallel and Distributed Computing.« less

Nonaqueous capillary electrophoresis of dextromethorphan and its metabolites.

PubMed

Pelcová, Marta; Langmajerová, Monika; Cvingráfová, Eliška; Juřica, Jan; Glatz, Zdeněk

2014-10-01

This study deals with the nonaqueous capillary electrophoretic separation of dextromethorphan and its metabolites using a methanolic background electrolyte. The optimization of separation conditions was performed in terms of the resolution of dextromethorphan and dextrorphan and the effect of separation temperature, voltage, and the characteristics of the background electrolyte were studied. Complete separation of all analytes was achieved in 40 mM ammonium acetate dissolved in methanol. Hydrodynamic injection was performed at 3 kPa for 4 s. The separation voltage was 20 kV accompanied by a low electric current. The ultraviolet detection was performed at 214 nm, the temperature of the capillary was 25°C. These conditions enabled the separation of four analytes plus the internal standard within 9 min. Further, the developed method was validated in terms of linearity, sensitivity, and repeatability. Rat liver perfusate samples were subjected to the nonaqueous capillary electrophoretic method to illustrate its applicability. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Learning the ideal observer for SKE detection tasks by use of convolutional neural networks (Cum Laude Poster Award)

NASA Astrophysics Data System (ADS)

Zhou, Weimin; Anastasio, Mark A.

2018-03-01

It has been advocated that task-based measures of image quality (IQ) should be employed to evaluate and optimize imaging systems. Task-based measures of IQ quantify the performance of an observer on a medically relevant task. The Bayesian Ideal Observer (IO), which employs complete statistical information of the object and noise, achieves the upper limit of the performance for a binary signal classification task. However, computing the IO performance is generally analytically intractable and can be computationally burdensome when Markov-chain Monte Carlo (MCMC) techniques are employed. In this paper, supervised learning with convolutional neural networks (CNNs) is employed to approximate the IO test statistics for a signal-known-exactly and background-known-exactly (SKE/BKE) binary detection task. The receiver operating characteristic (ROC) curve and the area under the ROC curve (AUC) are compared to those produced by the analytically computed IO. The advantages of the proposed supervised learning approach for approximating the IO are demonstrated.

On the performance of energy detection-based CR with SC diversity over IG channel

NASA Astrophysics Data System (ADS)

Verma, Pappu Kumar; Soni, Sanjay Kumar; Jain, Priyanka

2017-12-01

Cognitive radio (CR) is a viable 5G technology to address the scarcity of the spectrum. Energy detection-based sensing is known to be the simplest method as far as hardware complexity is concerned. In this paper, the performance of spectrum sensing-based energy detection technique in CR networks over inverse Gaussian channel for selection combining diversity technique is analysed. More specifically, accurate analytical expressions for the average detection probability under different detection scenarios such as single channel (no diversity) and with diversity reception are derived and evaluated. Further, the detection threshold parameter is optimised by minimising the probability of error over several diversity branches. The results clearly show the significant improvement in the probability of detection when optimised threshold parameter is applied. The impact of shadowing parameters on the performance of energy detector is studied in terms of complimentary receiver operating characteristic curve. To verify the correctness of our analysis, the derived analytical expressions are corroborated via exact result and Monte Carlo simulations.

A novel approach to rapidly explore analytical markers for quality control of Radix Salviae Miltiorrhizae extract granules by robust principal component analysis with ultra-high performance liquid chromatography-ultraviolet-quadrupole time-of-flight mass spectrometry.

PubMed

Song, Jing-Zheng; Li, Song-Lin; Zhou, Yan; Qiao, Chun-Feng; Chen, Shi-Lin; Xu, Hong-Xi

2010-11-02

In a well-controlled experiment, outliers discriminated by robust principal component analysis (RPCA) represent contents in samples which are of particular quality distinguishable from the rest of the others, therefore chemical constituents in a natural product causing discrimination between outliers and the majority of samples could be considered as analytical markers for quality control. Based on this strategy, a novel approach for rapidly exploring characteristic analytical markers was proposed for the quality control of extract granules of Radix Salviae Miltiorrhizae (EGRSM). In this study, large sizes of samples were analyzed via high-throughput ultra-high performance liquid chromatography-ultraviolet-quadrupole time-of-flight mass spectrometry (UHPLC-UV-Q-Tof MS). RPCA was first performed on the three groups of samples: RSM (the raw material), the in-house prepared aqueous extract of Radix Salviae Miltiorrhizae (AERSM) and commercial product of EGRSM, to determine the variation of specific constituents between raw material and the final products as well as the effect of manufacturing process on the overall quality. Then RPCA was performed on the commercial products of EGRSM to explore the applicability of identified characteristic markers for the quality control of EGRSM. Candidate markers were extracted by RPCA, and their molecular formulae were determined by high resolution electrospray ionization-mass spectrometric (ESI-MS) analysis. The suitability of identified markers was then evaluated by determining the relationship between quantities of the identified markers with their antioxidant activities biologically, and further confirmed in a variety of samples. In conclusion, the combination of RPCA with UHPLC-UV-Q-Tof MS is a reliable means to identify chemical markers for evaluating quality of herbal medicines. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Development of electrical feedback controlled heat pipes and the advanced thermal control flight experiment

NASA Technical Reports Server (NTRS)

Bienert, W. B.

1974-01-01

The development and characteristics of electrical feedback controlled heat pipes (FCHP) are discussed. An analytical model was produced to describe the performance of the FCHP under steady state and transient conditions. An advanced thermal control flight experiment was designed to demonstrate the performance of the thermal control component in a space environment. The thermal control equipment was evaluated on the ATS-F satellite to provide performance data for the components and to act as a thermal control system which can be used to provide temperature stability of spacecraft components in future applications.

Business Performance Measurements in Asset Management with the Support of Big Data Technologies

NASA Astrophysics Data System (ADS)

Campos, Jaime; Sharma, Pankaj; Jantunen, Erkki; Baglee, David; Fumagalli, Luca

2017-09-01

The paper reviews the performance measurement in the domain of interest. Important data in asset management are further, discussed. The importance and the characteristics of today's ICTs capabilities are also mentioned in the paper. The role of new concepts such as big data and data mining analytical technologies in managing the performance measurements in asset management are discussed in detail. The authors consequently suggest the use of the modified Balanced Scorecard methodology highlighting both quantitative and qualitative aspects, which is crucial for optimal use of the big data approach and technologies.

Stiffness modeling of compliant parallel mechanisms and applications in the performance analysis of a decoupled parallel compliant stage

NASA Astrophysics Data System (ADS)

Jiang, Yao; Li, Tie-Min; Wang, Li-Ping

2015-09-01

This paper investigates the stiffness modeling of compliant parallel mechanism (CPM) based on the matrix method. First, the general compliance matrix of a serial flexure chain is derived. The stiffness modeling of CPMs is next discussed in detail, considering the relative positions of the applied load and the selected displacement output point. The derived stiffness models have simple and explicit forms, and the input, output, and coupling stiffness matrices of the CPM can easily be obtained. The proposed analytical model is applied to the stiffness modeling and performance analysis of an XY parallel compliant stage with input and output decoupling characteristics. Then, the key geometrical parameters of the stage are optimized to obtain the minimum input decoupling degree. Finally, a prototype of the compliant stage is developed and its input axial stiffness, coupling characteristics, positioning resolution, and circular contouring performance are tested. The results demonstrate the excellent performance of the compliant stage and verify the effectiveness of the proposed theoretical model. The general stiffness models provided in this paper will be helpful for performance analysis, especially in determining coupling characteristics, and the structure optimization of the CPM.

Know Thy Student! Combining Learning Analytics and Critical Reflections to Increase Understanding of Students' Self-Regulated Learning in an Authentic Setting

ERIC Educational Resources Information Center

Colthorpe, Kay; Zimbardi, Kirsten; Ainscough, Louise; Anderson, Stephen

2015-01-01

It is well established that a student's capacity to regulate his or her own learning is a key determinant of academic success, suggesting that interventions targeting improvements in self-regulation will have a positive impact on academic performance. However, to evaluate the success of such interventions, the self-regulatory characteristics of…

Processing mode during repetitive thinking in socially anxious individuals: evidence for a maladaptive experiential mode.

PubMed

Wong, Quincy J J; Moulds, Michelle L

2012-12-01

Evidence from the depression literature suggests that an analytical processing mode adopted during repetitive thinking leads to maladaptive outcomes relative to an experiential processing mode. To date, in socially anxious individuals, the impact of processing mode during repetitive thinking related to an actual social-evaluative situation has not been investigated. We thus tested whether an analytical processing mode would be maladaptive relative to an experiential processing mode during anticipatory processing and post-event rumination. High and low socially anxious participants were induced to engage in either an analytical or experiential processing mode during: (a) anticipatory processing before performing a speech (Experiment 1; N = 94), or (b) post-event rumination after performing a speech (Experiment 2; N = 74). Mood, cognition, and behavioural measures were employed to examine the effects of processing mode. For high socially anxious participants, the modes had a similar effect on self-reported anxiety during both anticipatory processing and post-event rumination. Unexpectedly, relative to the analytical mode, the experiential mode led to stronger high standard and conditional beliefs during anticipatory processing, and stronger unconditional beliefs during post-event rumination. These experiments are the first to investigate processing mode during anticipatory processing and post-event rumination. Hence, these results are novel and will need to be replicated. These findings suggest that an experiential processing mode is maladaptive relative to an analytical processing mode during repetitive thinking characteristic of socially anxious individuals. Copyright © 2012 Elsevier Ltd. All rights reserved.

Analytical modeling and experimental validation of a magnetorheological mount

NASA Astrophysics Data System (ADS)

Nguyen, The; Ciocanel, Constantin; Elahinia, Mohammad

2009-03-01

Magnetorheological (MR) fluid has been increasingly researched and applied in vibration isolation devices. To date, the suspension system of several high performance vehicles has been equipped with MR fluid based dampers and research is ongoing to develop MR fluid based mounts for engine and powertrain isolation. MR fluid based devices have received attention due to the MR fluid's capability to change its properties in the presence of a magnetic field. This characteristic places MR mounts in the class of semiactive isolators making them a desirable substitution for the passive hydraulic mounts. In this research, an analytical model of a mixed-mode MR mount was constructed. The magnetorheological mount employs flow (valve) mode and squeeze mode. Each mode is powered by an independent electromagnet, so one mode does not affect the operation of the other. The analytical model was used to predict the performance of the MR mount with different sets of parameters. Furthermore, in order to produce the actual prototype, the analytical model was used to identify the optimal geometry of the mount. The experimental phase of this research was carried by fabricating and testing the actual MR mount. The manufactured mount was tested to evaluate the effectiveness of each mode individually and in combination. The experimental results were also used to validate the ability of the analytical model in predicting the response of the MR mount. Based on the observed response of the mount a suitable controller can be designed for it. However, the control scheme is not addressed in this study.

Analytical and experimental evaluations of the effect of broad property fuels on combustors for commercial aircraft gas turbine engines

NASA Technical Reports Server (NTRS)

Smith, A. L.

1980-01-01

The impacts of broad property fuels on the design, performance, durability, emissions, and operational characteristics of current and advanced combustors for commercial aircraft gas turbine engines were studied. The effect of fuel thermal stability on engine and airframe fuel system was evaluated. Tradeoffs between fuel properties, exhaust emissions, and combustor life were also investigated. Results indicate major impacts of broad property fuels on allowable metal temperatures in fuel manifolds and injector support, combustor cyclic durability, and somewhat lesser impacts on starting characteristics, lightoff, emissions, and smoke.

Cooling characteristics of air cooled radial turbine blades

NASA Astrophysics Data System (ADS)

Sato, T.; Takeishi, K.; Matsuura, M.; Miyauchi, J.

The cooling design and the cooling characteristics of air cooled radial turbine wheels, which are designed for use with the gas generator turbine for the 400 horse power truck gas turbine engine, are presented. A high temperature and high speed test was performed under aerodynamically similar conditions to that of the prototype engine in order to confirm the metal temperature of the newly developed integrated casting wheels constructed of the superalloys INCO 713C. The test results compared with the analytical value, which was established on the basis of the results of the heat transfer test and the water flow test, are discussed.

Performance characteristics of three-phase induction motors

NASA Technical Reports Server (NTRS)

Wood, M. E.

1977-01-01

An investigation into the characteristics of three phase, 400 Hz, induction motors of the general type used on aircraft and spacecraft is summarized. Results of laboratory tests are presented and compared with results from a computer program. Representative motors were both tested and simulated under nominal conditions as well as off nominal conditions of temperature, frequency, voltage magnitude, and voltage balance. Good correlation was achieved between simulated and laboratory results. The primary purpose of the program was to verify the simulation accuracy of the computer program, which in turn will be used as an analytical tool to support the shuttle orbiter.

Experimental investigation of recirculating cells in laminar coaxial jets.

NASA Technical Reports Server (NTRS)

Warpinski, N. R.; Nagib, H. M.; Lavan, Z.

1972-01-01

Utilizing several unique means of introducing smoke into the flow field for careful visualization in addition to hot-wire techniques, experiments are performed in a specially designed facility producing laminar flows up to considerably high Reynolds numbers. Characteristics of the cells and the flow conditions that bring them about are documented by smoke photographs in the Reynolds number velocity ratio plane and the results are compared to previous analytical predictions. The cells are found to fall into three categories with different flow characteristics involving unsteadiness in position, and shear layer instabilities which result in higher mixing with the outer streams.-

Drift-Free Position Estimation of Periodic or Quasi-Periodic Motion Using Inertial Sensors

PubMed Central

Latt, Win Tun; Veluvolu, Kalyana Chakravarthy; Ang, Wei Tech

2011-01-01

Position sensing with inertial sensors such as accelerometers and gyroscopes usually requires other aided sensors or prior knowledge of motion characteristics to remove position drift resulting from integration of acceleration or velocity so as to obtain accurate position estimation. A method based on analytical integration has previously been developed to obtain accurate position estimate of periodic or quasi-periodic motion from inertial sensors using prior knowledge of the motion but without using aided sensors. In this paper, a new method is proposed which employs linear filtering stage coupled with adaptive filtering stage to remove drift and attenuation. The prior knowledge of the motion the proposed method requires is only approximate band of frequencies of the motion. Existing adaptive filtering methods based on Fourier series such as weighted-frequency Fourier linear combiner (WFLC), and band-limited multiple Fourier linear combiner (BMFLC) are modified to combine with the proposed method. To validate and compare the performance of the proposed method with the method based on analytical integration, simulation study is performed using periodic signals as well as real physiological tremor data, and real-time experiments are conducted using an ADXL-203 accelerometer. Results demonstrate that the performance of the proposed method outperforms the existing analytical integration method. PMID:22163935

Integration and the performance of healthcare networks:do integration strategies enhance efficiency, profitability, and image?

PubMed Central

Wan, Thomas T.H.; Ma, Allen; Y.J.Lin, Blossom

2001-01-01

Abstract Purpose This study examines the integration effects on efficiency and financial viability of the top 100 integrated healthcare networks (IHNs) in the United States. Theory A contingency- strategic theory is used to identify the relationship of IHNs' performance to their structural and operational characteristics and integration strategies. Methods The lists of the top 100 IHNs ranked in two years, 1998 and 1999, by the SMG Marketing Group were merged to create a database for the study. Multiple indicators were used to examine the relationship between IHNs' characteristics and their performance in efficiency and financial viability. A path analytical model was developed and validated by the Mplus statistical program. Factors influencing the top 100 IHNs' images, represented by attaining ranking among the top 100 in two consecutive years, were analysed. Results and conclusion No positive associations were found between integration and network performance in efficiency or profits. Longitudinal data are needed to investigate the effect of integration on healthcare networks' financial performance. PMID:16896405

Strategies for dealing with missing data in clinical trials: from design to analysis.

PubMed

Dziura, James D; Post, Lori A; Zhao, Qing; Fu, Zhixuan; Peduzzi, Peter

2013-09-01

Randomized clinical trials are the gold standard for evaluating interventions as randomized assignment equalizes known and unknown characteristics between intervention groups. However, when participants miss visits, the ability to conduct an intent-to-treat analysis and draw conclusions about a causal link is compromised. As guidance to those performing clinical trials, this review is a non-technical overview of the consequences of missing data and a prescription for its treatment beyond the typical analytic approaches to the entire research process. Examples of bias from incorrect analysis with missing data and discussion of the advantages/disadvantages of analytic methods are given. As no single analysis is definitive when missing data occurs, strategies for its prevention throughout the course of a trial are presented. We aim to convey an appreciation for how missing data influences results and an understanding of the need for careful consideration of missing data during the design, planning, conduct, and analytic stages.

MODEL CORRELATION STUDY OF A RETRACTABLE BOOM FOR A SOLAR SAIL SPACECRAFT

NASA Technical Reports Server (NTRS)

Adetona, O.; Keel, L. H.; Oakley, J. D.; Kappus, K.; Whorton, M. S.; Kim, Y. K.; Rakpczy, J. M.

2005-01-01

To realize design concepts, predict dynamic behavior and develop appropriate control strategies for high performance operation of a solar-sail spacecraft, we developed a simple analytical model that represents dynamic behavior of spacecraft with various sizes. Since motion of the vehicle is dominated by retractable booms that support the structure, our study concentrates on developing and validating a dynamic model of a long retractable boom. Extensive tests with various configurations were conducted for the 30 Meter, light-weight, retractable, lattice boom at NASA MSFC that is structurally and dynamically similar to those of a solar-sail spacecraft currently under construction. Experimental data were then compared with the corresponding response of the analytical model. Though mixed results were obtained, the analytical model emulates several key characteristics of the boom. The paper concludes with a detailed discussion of issues observed during the study.

Study of a vibrating plate: comparison between experimental (ESPI) and analytical results

NASA Astrophysics Data System (ADS)

Romero, G.; Alvarez, L.; Alanís, E.; Nallim, L.; Grossi, R.

2003-07-01

Real-time electronic speckle pattern interferometry (ESPI) was used for tuning and visualization of natural frequencies of a trapezoidal plate. The plate was excited to resonant vibration by a sinusoidal acoustical source, which provided a continuous range of audio frequencies. Fringe patterns produced during the time-average recording of the vibrating plate—corresponding to several resonant frequencies—were registered. From these interferograms, calculations of vibrational amplitudes by means of zero-order Bessel functions were performed in some particular cases. The system was also studied analytically. The analytical approach developed is based on the Rayleigh-Ritz method and on the use of non-orthogonal right triangular co-ordinates. The deflection of the plate is approximated by a set of beam characteristic orthogonal polynomials generated by using the Gram-Schmidt procedure. A high degree of correlation between computational analysis and experimental results was observed.

Functional-analytical capabilities of GIS technology in the study of water use risks

NASA Astrophysics Data System (ADS)

Nevidimova, O. G.; Yankovich, E. P.; Yankovich, K. S.

2015-02-01

Regional security aspects of economic activities are of great importance for legal regulation in environmental management. This has become a critical issue due to climate change, especially in regions where severe climate conditions have a great impact on almost all types of natural resource uses. A detailed analysis of climate and hydrological situation in Tomsk Oblast considering water use risks was carried out. Based on developed author's techniques an informational and analytical database was created using ArcGIS software platform, which combines statistical (quantitative) and spatial characteristics of natural hazards and socio-economic factors. This system was employed to perform areal zoning according to the degree of water use risks involved.

[Advances of poly (ionic liquid) materials in separation science].

PubMed

Liu, Cuicui; Guo, Ting; Su, Rina; Gu, Yuchen; Deng, Qiliang

2015-11-01

Ionic liquids, as novel ionization reagents, possess beneficial characteristics including good solubility, conductivity, thermal stability, biocompatibility, low volatility and non-flammability. Ionic liquids are attracting a mass of attention of analytical chemists. Poly (ionic liquid) materials have common performances of ionic liquids and polymers, and have been successfully applied in separation science area. In this paper, we discuss the interaction mechanisms between the poly(ionic liquid) materials and analytes including hydrophobic/hydrophilic interactions, hydrogen bond, ion exchange, π-π stacking and electrostatic interactions, and summarize the application advances of the poly(ionic liquid) materials in solid phase extraction, chromatographic separation and capillary electrophoresis. At last, we describe the future prospect of poly(ionic liquid) materials.

Validation of Electrochemically Modulated Separations Performed On-Line with MC-ICP-MS for Uranium and Plutonium Isotopic Analyses

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

Liezers, Martin; Olsen, Khris B.; Mitroshkov, Alexandre V.

2010-08-11

The most time consuming process in uranium or plutonium isotopic analyses is performing the requisite chromatographic separation of the actinides. Filament preparation for thermal ionization (TIMS) adds further delays, but is generally accepted due to the unmatched performance in trace isotopic analyses. Advances in Multi-Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS) are beginning to rival the performance of TIMS. Methods, such as Electrochemically Modulated Separations (EMS) can efficiently pre-concentrate U or Pu quite selectively from small solution volumes in a matrix of 0.5 M nitric acid. When performed in-line with ICP-MS, the rapid analyte release from the electrode is fast,more » and large transient analyte signal enhancements of >100 fold can be achieved as compared to more conventional continuous nebulization of the original starting solution. This makes the approach ideal for very low level isotope ratio measurements. In this paper, some aspects of EMS performance are described. These include low level Pu isotope ratio behavior versus concentration by MC-ICP-MS and uranium rejection characteristics that are also important for reliable low level Pu isotope ratio determinations.« less

Design Considerations of ISTAR Hydrocarbon Fueled Combustor Operating in Air Augmented Rocket, Ramjet and Scramjet Modes

NASA Technical Reports Server (NTRS)

Andreadis, Dean; Drake, Alan; Garrett, Joseph L.; Gettinger, Christopher D.; Hoxie, Stephen S.

2003-01-01

The development and ground test of a rocket-based combined cycle (RBCC) propulsion system is being conducted as part of the NASA Marshall Space Flight Center (MSFC) Integrated System Test of an Airbreathing Rocket (ISTAR) program. The eventual flight vehicle (X-43B) is designed to support an air-launched self-powered Mach 0.7 to 7.0 demonstration of an RBCC engine through all of its airbreathing propulsion modes - air augmented rocket (AAR), ramjet (RJ), and scramjet (SJ). Through the use of analytical tools, numerical simulations, and experimental tests the ISTAR program is developing and validating a hydrocarbon-fueled RBCC combustor design methodology. This methodology will then be used to design an integrated RBCC propulsion system that produces robust ignition and combustion stability characteristics while maximizing combustion efficiency and minimizing drag losses. First order analytical and numerical methods used to design hydrocarbon-fueled combustors are discussed with emphasis on the methods and determination of requirements necessary to establish engine operability and performance characteristics.

Design Considerations of Istar Hydrocarbon Fueled Combustor Operating in Air Augmented Rocket, Ramjet and Scramjet Modes

NASA Technical Reports Server (NTRS)

Andreadis, Dean; Drake, Alan; Garrett, Joseph L.; Gettinger, Christopher D.; Hoxie, Stephen S.

2002-01-01

The development and ground test of a rocket-based combined cycle (RBCC) propulsion system is being conducted as part of the NASA Marshall Space Flight Center (MSFC) Integrated System Test of an Airbreathing Rocket (ISTAR) program. The eventual flight vehicle (X-43B) is designed to support an air-launched self-powered Mach 0.7 to 7.0 demonstration of an RBCC engine through all of its airbreathing propulsion modes - air augmented rocket (AAR), ramjet (RJ), and scramjet (SJ). Through the use of analytical tools, numerical simulations, and experimental tests the ISTAR program is developing and validating a hydrocarbon-fueled RBCC combustor design methodology. This methodology will then be used to design an integrated RBCC propulsion system thai: produces robust ignition and combustion stability characteristics while maximizing combustion efficiency and minimizing drag losses. First order analytical and numerical methods used to design hydrocarbon-fueled combustors are discussed with emphasis on the methods and determination of requirements necessary to establish engine operability and performance characteristics.

Effects of joints in truss structures

NASA Technical Reports Server (NTRS)

Ikegami, R.

1988-01-01

The response of truss-type structures for future space applications, such as Large Deployable Reflector (LDR), will be directly affected by joint performance. Some of the objectives of research at BAC were to characterize structural joints, establish analytical approaches that incorporate joint characteristics, and experimentally establish the validity of the analytical approaches. The test approach to characterize joints for both erectable and deployable-type structures was based upon a Force State Mapping Technique. The approach pictorially shows how the nonlinear joint results can be used for equivalent linear analysis. Testing of the Space Station joints developed at LaRC (a hinged joint at 2 Hz and a clevis joint at 2 Hz) successfully revealed the nonlinear characteristics of the joints. The Space Station joints were effectively linear when loaded to plus or minus 500 pounds with a corresponding displacement of about plus or minus 0.0015 inch. It was indicated that good linear joints exist which are compatible with errected structures, but that difficulty may be encountered if nonlinear-type joints are incorporated in the structure.

Real-time analysis of healthcare using big data analytics

NASA Astrophysics Data System (ADS)

Basco, J. Antony; Senthilkumar, N. C.

2017-11-01

Big Data Analytics (BDA) provides a tremendous advantage where there is a need of revolutionary performance in handling large amount of data that covers 4 characteristics such as Volume Velocity Variety Veracity. BDA has the ability to handle such dynamic data providing functioning effectiveness and exceptionally beneficial output in several day to day applications for various organizations. Healthcare is one of the sectors which generate data constantly covering all four characteristics with outstanding growth. There are several challenges in processing patient records which deals with variety of structured and unstructured format. Inducing BDA in to Healthcare (HBDA) will deal with sensitive patient driven information mostly in unstructured format comprising of prescriptions, reports, data from imaging system, etc., the challenges will be overcome by big data with enhanced efficiency in fetching and storing of data. In this project, dataset alike Electronic Medical Records (EMR) produced from numerous medical devices and mobile applications will be induced into MongoDB using Hadoop framework with Improvised processing technique to improve outcome of processing patient records.

Fluid mechanics of dynamic stall. II - Prediction of full scale characteristics

NASA Technical Reports Server (NTRS)

Ericsson, L. E.; Reding, J. P.

1988-01-01

Analytical extrapolations are made from experimental subscale dynamics to predict full scale characteristics of dynamic stall. The method proceeds by establishing analytic relationships between dynamic and static aerodynamic characteristics induced by viscous flow effects. The method is then validated by predicting dynamic test results on the basis of corresponding static test data obtained at the same subscale flow conditions, and the effect of Reynolds number on the static aerodynamic characteristics are determined from subscale to full scale flow conditions.

Novel immunoassay formats for integrated microfluidic circuits: diffusion immunoassays (DIA)

NASA Astrophysics Data System (ADS)

Weigl, Bernhard H.; Hatch, Anson; Kamholz, Andrew E.; Yager, Paul

2000-03-01

Novel designs of integrated fluidic microchips allow separations, chemical reactions, and calibration-free analytical measurements to be performed directly in very small quantities of complex samples such as whole blood and contaminated environmental samples. This technology lends itself to applications such as clinical diagnostics, including tumor marker screening, and environmental sensing in remote locations. Lab-on-a-Chip based systems offer many *advantages over traditional analytical devices: They consume extremely low volumes of both samples and reagents. Each chip is inexpensive and small. The sampling-to-result time is extremely short. They perform all analytical functions, including sampling, sample pretreatment, separation, dilution, and mixing steps, chemical reactions, and detection in an integrated microfluidic circuit. Lab-on-a-Chip systems enable the design of small, portable, rugged, low-cost, easy to use, yet extremely versatile and capable diagnostic instruments. In addition, fluids flowing in microchannels exhibit unique characteristics ('microfluidics'), which allow the design of analytical devices and assay formats that would not function on a macroscale. Existing Lab-on-a-chip technologies work very well for highly predictable and homogeneous samples common in genetic testing and drug discovery processes. One of the biggest challenges for current Labs-on-a-chip, however, is to perform analysis in the presence of the complexity and heterogeneity of actual samples such as whole blood or contaminated environmental samples. Micronics has developed a variety of Lab-on-a-Chip assays that can overcome those shortcomings. We will now present various types of novel Lab- on-a-Chip-based immunoassays, including the so-called Diffusion Immunoassays (DIA) that are based on the competitive laminar diffusion of analyte molecules and tracer molecules into a region of the chip containing antibodies that target the analyte molecules. Advantages of this technique are a reduction in reagents, higher sensitivity, minimal preparation of complex samples such as blood, real-time calibration, and extremely rapid analysis.

Differential homogeneous immunosensor device

DOEpatents

Malmros, Mark K.; Gulbinski, III, Julian

1990-04-10

There is provided a novel method of testing for the presence of an analyte in a fluid suspected of containing the same. In this method, in the presence of the analyte, a substance capable of modifying certain characteristics of the substrate is bound to the substrate and the change in these qualities is measured. While the method may be modified for carrying out quantitative differential analyses, it eliminates the need for washing analyte from the substrate which is characteristic of prior art methods.

Preparing Earth Data Scientists for 'The Sexiest Job of the 21st Century'

NASA Technical Reports Server (NTRS)

Kempler, Steven

2014-01-01

What Exactly do Earth Data Scientists do, and What do They Need to Know, to do It? There is not one simple answer, but there are many complex answers. Data Science, and data analytics, are new and nebulas, and takes on different characteristics depending on: The subject matter being analyzed, the maturity of the research, and whether the employed subject specific analytics is descriptive, diagnostic, discoveritive, predictive, or prescriptive, in nature. In addition, in a, thus far, business driven paradigm shift, university curriculums teaching data analytics pertaining to Earth science have, as a whole, lagged behind, andor have varied in approach.This presentation attempts to breakdown and identify the many activities that Earth Data Scientists, as a profession, encounter, as well as provide case studies of specific Earth Data Scientist and data analytics efforts. I will also address the educational preparation, that best equips future Earth Data Scientists, needed to further Earth science heterogeneous data research and applications analysis. The goal of this presentation is to describe the actual need for Earth Data Scientists and the practical skills to perform Earth science data analytics, thus hoping to initiate discussion addressing a baseline set of needed expertise for educating future Earth Data Scientists.

Experimental and analytical comparison of flowfields in a 110 N (25 lbf) H2/O2 rocket

NASA Technical Reports Server (NTRS)

Reed, Brian D.; Penko, Paul F.; Schneider, Steven J.; Kim, Suk C.

1991-01-01

A gaseous hydrogen/gaseous oxygen 110 N (25 lbf) rocket was examined through the RPLUS code using the full Navier-Stokes equations with finite rate chemistry. Performance tests were conducted on the rocket in an altitude test facility. Preliminary parametric analyses were performed for a range of mixture ratios and fuel film cooling pcts. It is shown that the computed values of specific impulse and characteristic exhaust velocity follow the trend of the experimental data. Specific impulse computed by the code is lower than the comparable test values by about two to three percent. The computed characteristic exhaust velocity values are lower than the comparable test values by three to four pct. Thrust coefficients computed by the code are found to be within two pct. of the measured values. It is concluded that the discrepancy between computed and experimental performance values could not be attributed to experimental uncertainty.

a New Golf-Swing Robot Model Utilizing Shaft Elasticity

NASA Astrophysics Data System (ADS)

Suzuki, S.; Inooka, H.

1998-10-01

The performance of golf clubs and balls is generally evaluated by using golf-swing robots that conventionally have two or three joints with completely interrelated motion. This interrelation allows the user of this robot to specify only the initial posture and swing velocity of the robot and therefore the swing motion of this type of robot cannot be subtly adjusted to the specific characteristics of individual golf clubs. Consequently, golf-swing robots cannot accurately emulate advanced golfers, and this causes serious problems for the evaluation of golf club performance. In this study, a new golf-swing robot that can adjust its motion to both a specified value of swing velocity and the specific characteristics of individual golf clubs was analytically investigated. This robot utilizes the dynamic interference force produced by its swing motion and by shaft vibration and can therefore emulate advanced golfers and perform highly reliable evaluations of golf clubs.

Thermal performance of multilayer insulations. [gas evacuation characteristics of three selected multilayer insulation composites

NASA Technical Reports Server (NTRS)

Keller, C. W.; Cunnington, G. R.; Glassford, A. P.

1974-01-01

Experimental and analytical studies were conducted in order to extend previous knowledge of the thermal performance and gas evacuation characteristics of three selected multilayer insulation (MLI) composites. Flat plate calorimeter heat flux measurements were obtained for 20- and 80- shield specimens using three representative layer densities over boundary temperatures ranging from 39 K (70 R) to 389 K (700 R). Laboratory gas evacuation tests were performed on representative specimens of each MLI composite after initially purging them with helium, nitrogen, or argon gases. In these tests, the specimens were maintained at temperatures between 128 K (230 R) and 300 K (540 R). Based on the results of the laboratory-scale tests, a composite MLI system consisting of 112 unperforated, double-aluminized Mylar reflective shields and 113 water preconditioned silk net spacer pairs was fabricated and installed on a 1.22-m-(4-ft-) diameter calorimeter tank.

Analytical validation of a novel multiplex test for detection of advanced adenoma and colorectal cancer in symptomatic patients.

PubMed

Dillon, Roslyn; Croner, Lisa J; Bucci, John; Kairs, Stefanie N; You, Jia; Beasley, Sharon; Blimline, Mark; Carino, Rochele B; Chan, Vicky C; Cuevas, Danissa; Diggs, Jeff; Jennings, Megan; Levy, Jacob; Mina, Ginger; Yee, Alvin; Wilcox, Bruce

2018-05-30

Early detection of colorectal cancer (CRC) is key to reducing associated mortality. Despite the importance of early detection, approximately 40% of individuals in the United States between the ages of 50-75 have never been screened for CRC. The low compliance with colonoscopy and fecal-based screening may be addressed with a non-invasive alternative such as a blood-based test. We describe here the analytical validation of a multiplexed blood-based assay that measures the plasma concentrations of 15 proteins to assess advanced adenoma (AA) and CRC risk in symptomatic patients. The test was developed on an electrochemiluminescent immunoassay platform employing four multi-marker panels, to be implemented in the clinic as a laboratory developed test (LDT). Under the Clinical Laboratory Improvement Amendments (CLIA) and College of American Pathologists (CAP) regulations, a United States-based clinical laboratory utilizing an LDT must establish performance characteristics relating to analytical validity prior to releasing patient test results. This report describes a series of studies demonstrating the precision, accuracy, analytical sensitivity, and analytical specificity for each of the 15 assays, as required by CLIA/CAP. In addition, the report describes studies characterizing each of the assays' dynamic range, parallelism, tolerance to common interfering substances, spike recovery, and stability to sample freeze-thaw cycles. Upon completion of the analytical characterization, a clinical accuracy study was performed to evaluate concordance of AA and CRC classifier model calls using the analytical method intended for use in the clinic. Of 434 symptomatic patient samples tested, the percent agreement with original CRC and AA calls was 87% and 92% respectively. All studies followed CLSI guidelines and met the regulatory requirements for implementation of a new LDT. The results provide the analytical evidence to support the implementation of the novel multi-marker test as a clinical test for evaluating CRC and AA risk in symptomatic individuals. Copyright © 2018 Elsevier B.V. All rights reserved.

Diversity Order Analysis of Dual-Hop Relaying with Partial Relay Selection

NASA Astrophysics Data System (ADS)

Bao, Vo Nguyen Quoc; Kong, Hyung Yun

In this paper, we study the performance of dual hop relaying in which the best relay selected by partial relay selection will help the source-destination link to overcome the channel impairment. Specifically, closed-form expressions for outage probability, symbol error probability and achievable diversity gain are derived using the statistical characteristic of the signal-to-noise ratio. Numerical investigation shows that the system achieves diversity of two regardless of relay number and also confirms the correctness of the analytical results. Furthermore, the performance loss due to partial relay selection is investigated.

A study of prediction methods for the high angle-of-attack aerodynamics of straight wings and fighter aircraft

NASA Technical Reports Server (NTRS)

Mcmillan, O. J.; Mendenhall, M. R.; Perkins, S. C., Jr.

1984-01-01

Work is described dealing with two areas which are dominated by the nonlinear effects of vortex flows. The first area concerns the stall/spin characteristics of a general aviation wing with a modified leading edge. The second area concerns the high-angle-of-attack characteristics of high performance military aircraft. For each area, the governing phenomena are described as identified with the aid of existing experimental data. Existing analytical methods are reviewed, and the most promising method for each area used to perform some preliminary calculations. Based on these results, the strengths and weaknesses of the methods are defined, and research programs recommended to improve the methods as a result of better understanding of the flow mechanisms involved.

Planar junctionless phototransistor: A potential high-performance and low-cost device for optical-communications

NASA Astrophysics Data System (ADS)

Ferhati, H.; Djeffal, F.

2017-12-01

In this paper, a new junctionless optical controlled field effect transistor (JL-OCFET) and its comprehensive theoretical model is proposed to achieve high optical performance and low cost fabrication process. Exhaustive study of the device characteristics and comparison between the proposed junctionless design and the conventional inversion mode structure (IM-OCFET) for similar dimensions are performed. Our investigation reveals that the proposed design exhibits an outstanding capability to be an alternative to the IM-OCFET due to the high performance and the weak signal detection benefit offered by this design. Moreover, the developed analytical expressions are exploited to formulate the objective functions to optimize the device performance using Genetic Algorithms (GAs) approach. The optimized JL-OCFET not only demonstrates good performance in terms of derived drain current and responsivity, but also exhibits superior signal to noise ratio, low power consumption, high-sensitivity, high ION/IOFF ratio and high-detectivity as compared to the conventional IM-OCFET counterpart. These characteristics make the optimized JL-OCFET potentially suitable for developing low cost and ultrasensitive photodetectors for high-performance and low cost inter-chips data communication applications.

Energy-dispersive X-ray fluorescence systems as analytical tool for assessment of contaminated soils.

PubMed

Vanhoof, Chris; Corthouts, Valère; Tirez, Kristof

2004-04-01

To determine the heavy metal content in soil samples at contaminated locations, a static and time consuming procedure is used in most cases. Soil samples are collected and analyzed in the laboratory at high quality and high analytical costs. The demand by government and consultants for a more dynamic approach and by customers requiring performances in which analyses are performed in the field with immediate feedback of the analytical results, is growing. Especially during the follow-up of remediation projects or during the determination of the sampling strategy, field analyses are advisable. For this purpose four types of ED-XRF systems, ranging from portable up to high performance laboratory systems, have been evaluated. The evaluation criteria are based on the performance characteristics for all the ED-XRF systems such as limit of detection, accuracy and the measurement uncertainty on one hand, and also the influence of the sample pretreatment on the obtained results on the other hand. The study proved that the field portable system and the bench top system, placed in a mobile van, can be applied as field techniques, resulting in semi-quantitative analytical results. A limited homogenization of the analyzed sample significantly increases the representativeness of the soil sample. The ED-XRF systems can be differentiated by their limits of detection which are a factor of 10 to 20 higher for the portable system. The accuracy of the results and the measurement uncertainty also improved using the bench top system. Therefore, the selection criteria for applicability of both field systems are based on the required detection level and also the required accuracy of the results.

Analytical performance, agreement and user-friendliness of six point-of-care testing urine analysers for urinary tract infection in general practice.

PubMed

Schot, Marjolein J C; van Delft, Sanne; Kooijman-Buiting, Antoinette M J; de Wit, Niek J; Hopstaken, Rogier M

2015-05-18

Various point-of-care testing (POCT) urine analysers are commercially available for routine urine analysis in general practice. The present study compares analytical performance, agreement and user-friendliness of six different POCT urine analysers for diagnosing urinary tract infection in general practice. All testing procedures were performed at a diagnostic centre for primary care in the Netherlands. Urine samples were collected at four general practices. Analytical performance and agreement of the POCT analysers regarding nitrite, leucocytes and erythrocytes, with the laboratory reference standard, was the primary outcome measure, and analysed by calculating sensitivity, specificity, positive and negative predictive value, and Cohen's κ coefficient for agreement. Secondary outcome measures were the user-friendliness of the POCT analysers, in addition to other characteristics of the analysers. The following six POCT analysers were evaluated: Uryxxon Relax (Macherey Nagel), Urisys 1100 (Roche), Clinitek Status (Siemens), Aution 11 (Menarini), Aution Micro (Menarini) and Urilyzer (Analyticon). Analytical performance was good for all analysers. Compared with laboratory reference standards, overall agreement was good, but differed per parameter and per analyser. Concerning the nitrite test, the most important test for clinical practice, all but one showed perfect agreement with the laboratory standard. For leucocytes and erythrocytes specificity was high, but sensitivity was considerably lower. Agreement for leucocytes varied between good to very good, and for the erythrocyte test between fair and good. First-time users indicated that the analysers were easy to use. They expected higher productivity and accuracy when using these analysers in daily practice. The overall performance and user-friendliness of all six commercially available POCT urine analysers was sufficient to justify routine use in suspected urinary tract infections in general practice. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Determination of free sulphydryl groups in wheat gluten under the influence of different time and temperature of incubation: method validation.

PubMed

Rakita, Slađana; Pojić, Milica; Tomić, Jelena; Torbica, Aleksandra

2014-05-01

The aim of the present study was to determine the characteristics of an analytical method for determination of free sulphydryl (SH) groups of wheat gluten performed with previous gluten incubation for variable times (45, 90 and 135min) at variable temperatures (30 and 37°C), in order to determine its fitness-for-purpose. It was observed that the increase in temperature and gluten incubation time caused the increase in the amount of free SH groups, with more dynamic changes at 37°C. The method characteristics identified as relevant were: linearity, limit of detection, limit of quantification, precision (repeatability and reproducibility) and measurement uncertainty, which were checked within the validation protocol, while the method performance was monitored by X- and R-control charts. Identified method characteristics demonstrated its acceptable fitness-for-purpose, when assay included previous gluten incubation at 30°C. Although the method repeatability at 37°C was acceptable, the corresponding reproducibility did not meet the performance criterion on the basis of HORRAT value (HORRAT<2). Copyright © 2013 Elsevier Ltd. All rights reserved.

Differential homogeneous immunosensor device

DOEpatents

Malmros, M.K.; Gulbinski, J. III.

1990-04-10

There is provided a novel method of testing for the presence of an analyte in a fluid suspected of containing the same. In this method, in the presence of the analyte, a substance capable of modifying certain characteristics of the substrate is bound to the substrate and the change in these qualities is measured. While the method may be modified for carrying out quantitative differential analyses, it eliminates the need for washing the analyte from the substrate which is characteristic of prior art methods. 12 figs.

AFGL Fiscal Year 1984 Air Force Technical Objectives Document.

DTIC Science & Technology

1982-11-01

the near term, to design the performance characteristics of sensors operating from the Shuttle. In the long term, these sensors will provide the...atmosphere are determined from sensors on rockets and satellites. These data, which are used to develop tailored analytic and predictive models for...toward increasing the flight time of the various vehicles. Future research and test- ing of advanced sensors will require rockets with increased

Application of Wear Debris Analysis to Aircraft Hydraulic Systems.

DTIC Science & Technology

1982-05-10

C. Wescott, "Predicting and Determining Failures by Means of Ferrography ", paper given at Ninth Annual FAA International Aviation Maintenance...morphological characteristics (reference (c)). In this particular effort the morphologi- cal studies were performed by means of analytical ferrography ...peak of 191,000 at 225 hours. As time progressed, the index again began to fall and returned to Ref: (c) "Wear Particle Atlas " Naval Air Engineering

Fatigue Performance of Advanced High-Strength Steels (AHSS) GMAW Joints

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

Feng, Zhili; Sang, Yan; Jiang, Cindy

2009-01-01

The fatigue performance of gas metal arc welding (GMAW) joints of advanced high strength steels (AHSS) are compared and analyzed. The steel studied included a number of different grades of AHSS and baseline mild steels: DP600, DP780, DP980, M130, M220, solution annealed boron steel, fully hardened boron steels, HSLA690 and DR210 (a mild steel). Fatigue testing was conducted under a number of nominal stress ranges to obtain the S/N curves of the weld joints. A two-phase analytical model is developed to predict the fatigue performance of AHSS welds. It was found that there are appreciable differences in the fatigue S/Nmore » curves among different AHSS joints made using the same welding practices, suggesting that the local microstructure in the weld toe and root region plays non-negligible role in the fatigue performance of AHSS welds. Changes in weld parameters can influence the joint characteristics which in turn influence fatigue life of the weld joints, particularly of those of higher strength AHSS. The analytical model is capable of reasonably predicting the fatigue performance of welds made with various steel grades in this study.« less

Tutorial in medical decision modeling incorporating waiting lines and queues using discrete event simulation.

PubMed

Jahn, Beate; Theurl, Engelbert; Siebert, Uwe; Pfeiffer, Karl-Peter

2010-01-01

In most decision-analytic models in health care, it is assumed that there is treatment without delay and availability of all required resources. Therefore, waiting times caused by limited resources and their impact on treatment effects and costs often remain unconsidered. Queuing theory enables mathematical analysis and the derivation of several performance measures of queuing systems. Nevertheless, an analytical approach with closed formulas is not always possible. Therefore, simulation techniques are used to evaluate systems that include queuing or waiting, for example, discrete event simulation. To include queuing in decision-analytic models requires a basic knowledge of queuing theory and of the underlying interrelationships. This tutorial introduces queuing theory. Analysts and decision-makers get an understanding of queue characteristics, modeling features, and its strength. Conceptual issues are covered, but the emphasis is on practical issues like modeling the arrival of patients. The treatment of coronary artery disease with percutaneous coronary intervention including stent placement serves as an illustrative queuing example. Discrete event simulation is applied to explicitly model resource capacities, to incorporate waiting lines and queues in the decision-analytic modeling example.

On the calculation of resonances by analytic continuation of eigenvalues from the stabilization graph

NASA Astrophysics Data System (ADS)

Haritan, Idan; Moiseyev, Nimrod

2017-07-01

Resonances play a major role in a large variety of fields in physics and chemistry. Accordingly, there is a growing interest in methods designed to calculate them. Recently, Landau et al. proposed a new approach to analytically dilate a single eigenvalue from the stabilization graph into the complex plane. This approach, termed Resonances Via Padé (RVP), utilizes the Padé approximant and is based on a unique analysis of the stabilization graph. Yet, analytic continuation of eigenvalues from the stabilization graph into the complex plane is not a new idea. In 1975, Jordan suggested an analytic continuation method based on the branch point structure of the stabilization graph. The method was later modified by McCurdy and McNutt, and it is still being used today. We refer to this method as the Truncated Characteristic Polynomial (TCP) method. In this manuscript, we perform an in-depth comparison between the RVP and the TCP methods. We demonstrate that while both methods are important and complementary, the advantage of one method over the other is problem-dependent. Illustrative examples are provided in the manuscript.

Translation of proteomic biomarkers into FDA approved cancer diagnostics: issues and challenges

PubMed Central

2013-01-01

Tremendous efforts have been made over the past few decades to discover novel cancer biomarkers for use in clinical practice. However, a striking discrepancy exists between the effort directed toward biomarker discovery and the number of markers that make it into clinical practice. One of the confounding issues in translating a novel discovery into clinical practice is that quite often the scientists working on biomarker discovery have limited knowledge of the analytical, diagnostic, and regulatory requirements for a clinical assay. This review provides an introduction to such considerations with the aim of generating more extensive discussion for study design, assay performance, and regulatory approval in the process of translating new proteomic biomarkers from discovery into cancer diagnostics. We first describe the analytical requirements for a robust clinical biomarker assay, including concepts of precision, trueness, specificity and analytical interference, and carryover. We next introduce the clinical considerations of diagnostic accuracy, receiver operating characteristic analysis, positive and negative predictive values, and clinical utility. We finish the review by describing components of the FDA approval process for protein-based biomarkers, including classification of biomarker assays as medical devices, analytical and clinical performance requirements, and the approval process workflow. While we recognize that the road from biomarker discovery, validation, and regulatory approval to the translation into the clinical setting could be long and difficult, the reward for patients, clinicians and scientists could be rather significant. PMID:24088261

Analytical Validation of a Portable Mass Spectrometer Featuring Interchangeable, Ambient Ionization Sources for High Throughput Forensic Evidence Screening

NASA Astrophysics Data System (ADS)

Lawton, Zachary E.; Traub, Angelica; Fatigante, William L.; Mancias, Jose; O'Leary, Adam E.; Hall, Seth E.; Wieland, Jamie R.; Oberacher, Herbert; Gizzi, Michael C.; Mulligan, Christopher C.

2017-06-01

Forensic evidentiary backlogs are indicative of the growing need for cost-effective, high-throughput instrumental methods. One such emerging technology that shows high promise in meeting this demand while also allowing on-site forensic investigation is portable mass spectrometric (MS) instrumentation, particularly that which enables the coupling to ambient ionization techniques. While the benefits of rapid, on-site screening of contraband can be anticipated, the inherent legal implications of field-collected data necessitates that the analytical performance of technology employed be commensurate with accepted techniques. To this end, comprehensive analytical validation studies are required before broad incorporation by forensic practitioners can be considered, and are the focus of this work. Pertinent performance characteristics such as throughput, selectivity, accuracy/precision, method robustness, and ruggedness have been investigated. Reliability in the form of false positive/negative response rates is also assessed, examining the effect of variables such as user training and experience level. To provide flexibility toward broad chemical evidence analysis, a suite of rapidly-interchangeable ion sources has been developed and characterized through the analysis of common illicit chemicals and emerging threats like substituted phenethylamines. [Figure not available: see fulltext.

Computing Platforms for Big Biological Data Analytics: Perspectives and Challenges.

PubMed

Yin, Zekun; Lan, Haidong; Tan, Guangming; Lu, Mian; Vasilakos, Athanasios V; Liu, Weiguo

2017-01-01

The last decade has witnessed an explosion in the amount of available biological sequence data, due to the rapid progress of high-throughput sequencing projects. However, the biological data amount is becoming so great that traditional data analysis platforms and methods can no longer meet the need to rapidly perform data analysis tasks in life sciences. As a result, both biologists and computer scientists are facing the challenge of gaining a profound insight into the deepest biological functions from big biological data. This in turn requires massive computational resources. Therefore, high performance computing (HPC) platforms are highly needed as well as efficient and scalable algorithms that can take advantage of these platforms. In this paper, we survey the state-of-the-art HPC platforms for big biological data analytics. We first list the characteristics of big biological data and popular computing platforms. Then we provide a taxonomy of different biological data analysis applications and a survey of the way they have been mapped onto various computing platforms. After that, we present a case study to compare the efficiency of different computing platforms for handling the classical biological sequence alignment problem. At last we discuss the open issues in big biological data analytics.

Tuning the gas sensing performance of single PEDOT nanowire devices.

PubMed

Hangarter, Carlos M; Hernandez, Sandra C; He, Xueing; Chartuprayoon, Nicha; Choa, Yong Ho; Myung, Nosang V

2011-06-07

This paper reports the synthesis and dopant dependent electrical and sensing properties of single poly(ethylenedioxythiophene) (PEDOT) nanowire sensors. Dopant type (i.e. polystyrenesulfonate (PSS(-)) and perchlorate (ClO(4)(-))) and solvent (i.e. acetonitrile and 1 : 1 water-acetonitrile mixture) were adjusted to change the conjugation length and hydrophilicity of nanowires which resulted in change of the electrical properties and sensing performance. Temperature dependent coefficient of resistance (TCR) indicated that the electrical properties are greatly dependent on dopants and electrolyte where greater disorder was found in PSS(-) doped PEDOT nanowires compared to ClO(4)(-) doped nanowires. Upon exposure to different analytes including water vapor and volatile organic compounds, these nanowire devices displayed substantially different sensing characteristics. ClO(4)(-) doped PEDOT nanowires from an acetonitrile bath show superior sensing responses toward less electronegative analytes and followed a power law dependence on the analyte concentration at high partial pressures. These tunable sensing properties were attributed to variation in the conjugation lengths, dopant type and concentration of the wires which may be attributed to two distinct sensing mechanisms: swelling within the bulk of the nanowire and work function modulation of Schottky barrier junction between nanowire and electrodes.

Assessment and prediction of drying shrinkage cracking in bonded mortar overlays

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

Beushausen, Hans, E-mail: hans.beushausen@uct.ac.za; Chilwesa, Masuzyo

2013-11-15

Restrained drying shrinkage cracking was investigated on composite beams consisting of substrate concrete and bonded mortar overlays, and compared to the performance of the same mortars when subjected to the ring test. Stress development and cracking in the composite specimens were analytically modeled and predicted based on the measurement of relevant time-dependent material properties such as drying shrinkage, elastic modulus, tensile relaxation and tensile strength. Overlay cracking in the composite beams could be very well predicted with the analytical model. The ring test provided a useful qualitative comparison of the cracking performance of the mortars. The duration of curing wasmore » found to only have a minor influence on crack development. This was ascribed to the fact that prolonged curing has a beneficial effect on tensile strength at the onset of stress development, but is in the same time not beneficial to the values of tensile relaxation and elastic modulus. -- Highlights: •Parameter study on material characteristics influencing overlay cracking. •Analytical model gives good quantitative indication of overlay cracking. •Ring test presents good qualitative indication of overlay cracking. •Curing duration has little effect on overlay cracking.« less

Parallel Aircraft Trajectory Optimization with Analytic Derivatives

NASA Technical Reports Server (NTRS)

Falck, Robert D.; Gray, Justin S.; Naylor, Bret

2016-01-01

Trajectory optimization is an integral component for the design of aerospace vehicles, but emerging aircraft technologies have introduced new demands on trajectory analysis that current tools are not well suited to address. Designing aircraft with technologies such as hybrid electric propulsion and morphing wings requires consideration of the operational behavior as well as the physical design characteristics of the aircraft. The addition of operational variables can dramatically increase the number of design variables which motivates the use of gradient based optimization with analytic derivatives to solve the larger optimization problems. In this work we develop an aircraft trajectory analysis tool using a Legendre-Gauss-Lobatto based collocation scheme, providing analytic derivatives via the OpenMDAO multidisciplinary optimization framework. This collocation method uses an implicit time integration scheme that provides a high degree of sparsity and thus several potential options for parallelization. The performance of the new implementation was investigated via a series of single and multi-trajectory optimizations using a combination of parallel computing and constraint aggregation. The computational performance results show that in order to take full advantage of the sparsity in the problem it is vital to parallelize both the non-linear analysis evaluations and the derivative computations themselves. The constraint aggregation results showed a significant numerical challenge due to difficulty in achieving tight convergence tolerances. Overall, the results demonstrate the value of applying analytic derivatives to trajectory optimization problems and lay the foundation for future application of this collocation based method to the design of aircraft with where operational scheduling of technologies is key to achieving good performance.

Statistically Qualified Neuro-Analytic system and Method for Process Monitoring

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

Vilim, Richard B.; Garcia, Humberto E.; Chen, Frederick W.

1998-11-04

An apparatus and method for monitoring a process involves development and application of a statistically qualified neuro-analytic (SQNA) model to accurately and reliably identify process change. The development of the SQNA model is accomplished in two steps: deterministic model adaption and stochastic model adaptation. Deterministic model adaption involves formulating an analytic model of the process representing known process characteristics,augmenting the analytic model with a neural network that captures unknown process characteristics, and training the resulting neuro-analytic model by adjusting the neural network weights according to a unique scaled equation emor minimization technique. Stochastic model adaptation involves qualifying any remaining uncertaintymore » in the trained neuro-analytic model by formulating a likelihood function, given an error propagation equation, for computing the probability that the neuro-analytic model generates measured process output. Preferably, the developed SQNA model is validated using known sequential probability ratio tests and applied to the process as an on-line monitoring system.« less

Powdered activated carbons as effective phases for bar adsorptive micro-extraction (BAμE) to monitor levels of triazinic herbicides in environmental water matrices.

PubMed

Neng, N R; Mestre, A S; Carvalho, A P; Nogueira, J M F

2011-02-15

Bar adsorptive micro-extraction using three powdered activated carbons (ACs) as adsorbent phases followed by liquid desorption and high performance liquid chromatography with diode array detection (BAμE(ACs)-LD/HPLC-DAD), was developed to monitor triazinic herbicides (atrazine, simazine and terbutylazine) in environmental water matrices. ACs used present apparent surface areas around 1000 m(2) g(-1) with an important mesoporous volume and distinct surface chemistry characteristics (pH(PZC) ranging from 6.5 to 10.4). The textural and surface chemistry properties of the ACs adsorbent phases were correlated with the analytical data for a better understanding of the overall enrichment process. Assays performed on 10 mL water samples spiked at the 10.0 μg L(-1) levels under optimized experimental conditions yielded recoveries around 100% for the three herbicides under study. The analytical performance showed good precision (RSD<15.0%), convenient detection limits (≈0.1 μg L(-1)) and suitable linearity (1.0-12.0 μg L(-1)) with good correlation coefficients (r(2)>0.9914). By using the standard addition method, the application of the present method on real water matrices, such as surface water and wastewater, allowed very good performances at the trace level. The proposed methodology proved to be a suitable sorptive extraction alternative for the analysis of priority pollutants with polar characteristics, showing to be easy to implement, reliable, sensitive and requiring a low sample volume to monitor triazinic compounds in water matrices. Copyright © 2010 Elsevier B.V. All rights reserved.

Specialized data analysis for the Space Shuttle Main Engine and diagnostic evaluation of advanced propulsion system components

NASA Technical Reports Server (NTRS)

1993-01-01

The Marshall Space Flight Center is responsible for the development and management of advanced launch vehicle propulsion systems, including the Space Shuttle Main Engine (SSME), which is presently operational, and the Space Transportation Main Engine (STME) under development. The SSME's provide high performance within stringent constraints on size, weight, and reliability. Based on operational experience, continuous design improvement is in progress to enhance system durability and reliability. Specialized data analysis and interpretation is required in support of SSME and advanced propulsion system diagnostic evaluations. Comprehensive evaluation of the dynamic measurements obtained from test and flight operations is necessary to provide timely assessment of the vibrational characteristics indicating the operational status of turbomachinery and other critical engine components. Efficient performance of this effort is critical due to the significant impact of dynamic evaluation results on ground test and launch schedules, and requires direct familiarity with SSME and derivative systems, test data acquisition, and diagnostic software. Detailed analysis and evaluation of dynamic measurements obtained during SSME and advanced system ground test and flight operations was performed including analytical/statistical assessment of component dynamic behavior, and the development and implementation of analytical/statistical models to efficiently define nominal component dynamic characteristics, detect anomalous behavior, and assess machinery operational condition. In addition, the SSME and J-2 data will be applied to develop vibroacoustic environments for advanced propulsion system components, as required. This study will provide timely assessment of engine component operational status, identify probable causes of malfunction, and indicate feasible engineering solutions. This contract will be performed through accomplishment of negotiated task orders.

Dynamic remapping of parallel computations with varying resource demands

NASA Technical Reports Server (NTRS)

Nicol, D. M.; Saltz, J. H.

1986-01-01

A large class of computational problems is characterized by frequent synchronization, and computational requirements which change as a function of time. When such a problem must be solved on a message passing multiprocessor machine, the combination of these characteristics lead to system performance which decreases in time. Performance can be improved with periodic redistribution of computational load; however, redistribution can exact a sometimes large delay cost. We study the issue of deciding when to invoke a global load remapping mechanism. Such a decision policy must effectively weigh the costs of remapping against the performance benefits. We treat this problem by constructing two analytic models which exhibit stochastically decreasing performance. One model is quite tractable; we are able to describe the optimal remapping algorithm, and the optimal decision policy governing when to invoke that algorithm. However, computational complexity prohibits the use of the optimal remapping decision policy. We then study the performance of a general remapping policy on both analytic models. This policy attempts to minimize a statistic W(n) which measures the system degradation (including the cost of remapping) per computation step over a period of n steps. We show that as a function of time, the expected value of W(n) has at most one minimum, and that when this minimum exists it defines the optimal fixed-interval remapping policy. Our decision policy appeals to this result by remapping when it estimates that W(n) is minimized. Our performance data suggests that this policy effectively finds the natural frequency of remapping. We also use the analytic models to express the relationship between performance and remapping cost, number of processors, and the computation's stochastic activity.

Channel characteristics and coordination in three-echelon dual-channel supply chain

NASA Astrophysics Data System (ADS)

Saha, Subrata

2016-02-01

We explore the impact of channel structure on the manufacturer, the distributer, the retailer and the entire supply chain by considering three different channel structures in radiance of with and without coordination. These structures include a traditional retail channel and two manufacturer direct channels with and without consistent pricing. By comparing the performance of the manufacturer, the distributer and the retailer, and the entire supply chain in three different supply chain structures, it is established analytically that, under some conditions, a dual channel can outperform a single retail channel; as a consequence, a coordination mechanism is developed that not only coordinates the dual channel but also outperforms the non-cooperative single retail channel. All the analytical results are further analysed through numerical examples.

CFD simulation of mechanical draft tube mixing in anaerobic digester tanks.

PubMed

Meroney, Robert N; Colorado, P E

2009-03-01

Computational Fluid Dynamics (CFD) was used to simulate the mixing characteristics of four different circular anaerobic digester tanks (diameters of 13.7, 21.3, 30.5, and 33.5m) equipped with single and multiple draft impeller tube mixers. Rates of mixing of step and slug injection of tracers were calculated from which digester volume turnover time (DVTT), mixture diffusion time (MDT), and hydraulic retention time (HRT) could be calculated. Washout characteristics were compared to analytic formulae to estimate any presence of partial mixing, dead volume, short-circuiting, or piston flow. CFD satisfactorily predicted performance of both model and full-scale circular tank configurations.

Surface analytical characterization of Streptavidin/poly(3-hexylthiophene) bilayers for bio-electronic applications

NASA Astrophysics Data System (ADS)

Sportelli, M. C.; Picca, R. A.; Manoli, K.; Re, M.; Pesce, E.; Tapfer, L.; Di Franco, C.; Cioffi, N.; Torsi, L.

2017-10-01

The analytical performance of bioelectronic devices is highly influenced by their fabrication methods. In particular, the final architecture of field-effect transistor biosensors combining spin-cast poly(3-hexylthiophene) (P3HT) film and a biomolecule interlayer deposited on a SiO2/Si substrate can lead to the development of highly performing sensing systems, such as for the case of streptavidin (SA) used for biotin sensing. To gain a better understanding of the quality of the interfacial area, critical is the assessment of the morphological features characteristic of the adopted biolayer deposition protocol, namely: the layer-by-layer (LbL) approach and the spin coating technique. The present study relies on a combined surface spectroscopic and morphological characterization. Specifically, X-ray photoelectron spectroscopy operated in the parallel angle-resolved mode allowed the non-destructive investigation of the in-depth chemical composition of the SA film, alone or in the presence of the P3HT overlayer. Spectroscopic data were supported and corroborated by the results obtained with a Scanning Electron and a Helium Ion microscope investigation performed on the SA layer that provided relevant information on the protein structural arrangement or on its surface morphology. Clear differences emerged between the SA layers prepared by the two approaches, with the layer-by-layer deposition resulting in a smoother and better defined bio-electronic interface. Such findings support the superior analytical performance shown by bioelectronic devices based on LbL-deposited protein layers over spin coated ones.

Experimental and analytical study of the DC breakdown characteristics of polypropylene laminated paper with a butt gap condition considering the insulation design of superconducting cable

NASA Astrophysics Data System (ADS)

Seo, In-jin; Choi, Won; Seong, Jae-gyu; Lee, Bang-wook; Koo, Ja-yoon

2014-08-01

It has been reported that the insulation design under DC stress is considered as one of the critical factors in determining the performance of high-voltage direct current (HVDC) superconducting cable. Therefore, it is fundamentally necessary to investigate the DC breakdown characteristics of the composite insulation system consisting of liquid nitrogen (LN2)/polypropylene-laminated-paper (PPLP). In particular, the insulation characteristics under DC polarity reversal condition should be verified to understand the polarity effect of the DC voltage considering the unexpected incidents taking place at line-commutated-converters (LCC) under service at a DC power grid. In this study, to examine the variation of DC electric field strength, the step voltage and polarity reversal breakdown tests are performed under DC stress. Also, we investigate the electric field distributions in a butt gap of the LN2/PPLP condition considering the DC polarity reversal by using simulation software.

Verification of out-of-control situations detected by "average of normal" approach.

PubMed

Liu, Jiakai; Tan, Chin Hon; Loh, Tze Ping; Badrick, Tony

2016-11-01

"Average of normal" (AoN) or "moving average" is increasingly used as an adjunct quality control tool in laboratory practice. Little guidance exists on how to verify if an out-of-control situation in the AoN chart is due to a shift in analytical performance, or underlying patient characteristics. Through simulation based on clinical data, we examined 1) the location of the last apparently stable period in the AoN control chart after an analytical shift, and 2) an approach to verify if the observed shift is related to an analytical shift by repeat testing of archived patient samples from the stable period for 21 common analytes. The number of blocks of results to look back for the stable period increased with the duration of the analytical shift, and was larger when smaller AoN block sizes were used. To verify an analytical shift, 3 archived samples from the analytically stable period should be retested. In particular, the process is deemed to have shifted if a difference of >2 analytical standard deviations (i.e. 1:2s rejection rule) between the original and retested results are observed in any of the 3 samples produced. The probability of Type-1 error (i.e., false rejection) and power (i.e., detecting true analytical shift) of this rule are <0.1 and >0.9, respectively. The use of appropriately archived patient samples to verify an apparent analytical shift is preferred to quality control materials. Nonetheless, the above findings may also apply to quality control materials, barring matrix effects. Copyright © 2016 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Development of a bar adsorptive micro-extraction-large-volume injection-gas chromatography-mass spectrometric method for pharmaceuticals and personal care products in environmental water matrices.

PubMed

Neng, N R; Nogueira, J M F

2012-01-01

The combination of bar adsorptive micro-extraction using activated carbon (AC) and polystyrene-divinylbenzene copolymer (PS-DVB) sorbent phases, followed by liquid desorption and large-volume injection gas chromatography coupled to mass spectrometry, under selected ion monitoring mode acquisition, was developed for the first time to monitor pharmaceutical and personal care products (PPCPs) in environmental water matrices. Assays performed on 25 mL water samples spiked (100 ng L(-1)) with caffeine, gemfibrozil, triclosan, propranolol, carbamazepine and diazepam, selected as model compounds, yielded recoveries ranging from 74% to 99% under optimised experimental conditions (equilibrium time, 16 h (1,000 rpm); matrix characteristics: pH 5, 5% NaCl for AC phase; LD: methanol/acetonitrile (1:1), 45 min). The analytical performance showed good precision (RSD < 18%), convenient detection limits (5-20 ng L(-1)) and excellent linear dynamic range (20-800 ng L(-1)) with remarkable determination coefficients (r(2) > 0.99), where the PS-DVB sorbent phase showed a much better efficiency. By using the standard addition methodology, the application of the present analytical approach on tap, ground, sea, estuary and wastewater samples allowed very good performance at the trace level. The proposed method proved to be a suitable sorption-based micro-extraction alternative for the analysis of priority pollutants with medium-polar to polar characteristics, showing to be easy to implement, reliable, sensitive and requiring a low sample volume to monitor PPCPs in water matrices.

Adaption of a parallel-path poly(tetrafluoroethylene) nebulizer to an evaporative light scattering detector: Optimization and application to studies of poly(dimethylsiloxane) oligomers as a model polymer.

PubMed

Durner, Bernhard; Ehmann, Thomas; Matysik, Frank-Michael

2018-06-05

The adaption of an parallel-path poly(tetrafluoroethylene)(PTFE) ICP-nebulizer to an evaporative light scattering detector (ELSD) was realized. This was done by substituting the originally installed concentric glass nebulizer of the ELSD. The performance of both nebulizers was compared regarding nebulizer temperature, evaporator temperature, flow rate of nebulizing gas and flow rate of mobile phase of different solvents using caffeine and poly(dimethylsiloxane) (PDMS) as analytes. Both nebulizers showed similar performances but for the parallel-path PTFE nebulizer the performance was considerably better at low LC flow rates and the nebulizer lifetime was substantially increased. In general, for both nebulizers the highest sensitivity was obtained by applying the lowest possible evaporator temperature in combination with the highest possible nebulizer temperature at preferably low gas flow rates. Besides the optimization of detector parameters, response factors for various PDMS oligomers were determined and the dependency of the detector signal on molar mass of the analytes was studied. The significant improvement regarding long-term stability made the modified ELSD much more robust and saved time and money by reducing the maintenance efforts. Thus, especially in polymer HPLC, associated with a complex matrix situation, the PTFE-based parallel-path nebulizer exhibits attractive characteristics for analytical studies of polymers. Copyright © 2018. Published by Elsevier B.V.

Analytical protocol for the sensitive determination of mannitol, sorbitol and glucose containing powders in pharmaceutical workplaces by ion chromatography using a pulsed amperometric detector.

PubMed

Butler, Owen; Forder, James; Saunders, John

2015-03-15

Workers in the pharmaceutical industry can potentially be exposed to airborne dusts and powders that can contain potent active pharmaceutical ingredients (API). Occupational hygienists and health and safety professionals need to assess and ultimately minimise such inhalation and dermal exposure risks. Containment of dusts at source is the first line of defence but the performance of such technologies needs to be verified, for which purpose the good practice guide: assessing the particulate containment performance of pharmaceutical equipment, produced by the International Society for Pharmaceutical Engineering (ISPE), is a widely used reference document. This guide recommends the use of surrogate powders that can be used to challenge the performance of such containment systems. Materials such as lactose and mannitol are recommended as their physical properties (adhesion, compactability, dustiness, flow characteristics and particle sizes) mimic those of API-containing materials typically handled. Furthermore they are safe materials to use, are available in high purity and can be procured at a reasonable cost. The aim of this work was to develop and validate a sensitive ion-chromatography based analytical procedure for the determination of surrogate powders collected on filter samples so as to meet analytical requirements set out in this ISPE guide. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

Development of SEM/STEM-WDX for highly sensitive detection of light elements

NASA Astrophysics Data System (ADS)

Anan, Y.; Koguchi, M.; Kimura, T.; Sekiguchi, T.

2018-02-01

In this study, to detect the light element lithium (Li) and to detect low dosed Boron (B) in the local area at nm order, we developed an analytical electron microscope equipped with an improved serial (S)-type WDX (wavelength dispersive X-ray spectroscopy) system. In detail, to detect Li, we developed a high-conductivity multi-capillary X-ray (MCX) lens, and a diffractor with a lattice spacing (d) of 15 nm, and with a spacing variation (δ d) of 0.8 nm. Moreover, to detect low dosed light element B, we designed a high-conductivity MCX lens based on the soft X-ray reflectivity in the capillary and calculation. We developed a large-solid-angle MCX lens whose conductivity of the characteristic X-rays of B became 20 times higher than that of an MCX lens with a 30-mm focal length. Our developed analytical electron microscope was applied to a LiAl specimen and a low B-doped Si substrate specimen, and the performance of this analytical electron microscope was evaluated. As a results, this analytical electron microscope could detect the characteristic X-rays of Li with a minimum mass fraction (MMF) of 8.4 atomic % (at. %). The energy resolution was 1 eV at 55 eV. From the results of measuring the line profile of B for the unpatterned B-implantation area on a B-doped Si substrate specimen, the measured line profile data were in good agreement with secondary ion mass spectrometry data up to a depth of 100 nm with a B concentration of 0.05 at. %.

The effect of density-of-state tails on band-to-band tunneling: Theory and application to tunnel field effect transistors

NASA Astrophysics Data System (ADS)

Sant, S.; Schenk, A.

2017-10-01

It is demonstrated how band tail states in the semiconductor influence the performance of a Tunnel Field Effect Transistor (TFET). As a consequence of the smoothened density of states (DOS) around the band edges, the energetic overlap of conduction and valence band states occurs gradually at the onset of band-to-band tunneling (BTBT), thus degrading the sub-threshold swing (SS) of the TFET. The effect of the band tail states on the current-voltage characteristics is modelled quantum-mechanically based on the idea of zero-phonon trap-assisted tunneling between band and tail states. The latter are assumed to arise from a 3-dimensional pseudo-delta potential proposed by Vinogradov [1]. This model potential allows the derivation of analytical expressions for the generation rate covering the whole range from very strong to very weak localization of the tail states. Comparison with direct BTBT in the one-band effective mass approximation reveals the essential features of tail-to-band tunneling. Furthermore, an analytical solution for the problem of tunneling from continuum states of the disturbed DOS to states in the opposite band is found, and the differences to direct BTBT are worked out. Based on the analytical expressions, a semi-classical model is implemented in a commercial device simulator which involves numerical integration along the tunnel paths. The impact of the tail states on the device performance is analyzed for a nanowire Gate-All-Around TFET. The simulations show that tail states notably impact the transfer characteristics of a TFET. It is found that exponentially decaying band tails result in a stronger degradation of the SS than tail states with a Gaussian decay of their density. The developed model allows more realistic simulations of TFETs including their non-idealities.

Simulation study of a new inverse-pinch high Coulomb transfer switch

NASA Technical Reports Server (NTRS)

Choi, S. H.

1984-01-01

A simulation study of a simplified model of a high coulomb transfer switch is performed. The switch operates in an inverse pinch geometry formed by an all metal chamber, which greatly reduces hot spot formations on the electrode surfaces. Advantages of the switch over the conventional switches are longer useful life, higher current capability and lower inductance, which improves the characteristics required for a high repetition rate switch. The simulation determines the design parameters by analytical computations and comparison with the experimentally measured risetime, current handling capability, electrode damage, and hold-off voltages. The parameters of initial switch design can be determined for the anticipated switch performance. Results are in agreement with the experiment results. Although the model is simplified, the switch characteristics such as risetime, current handling capability, electrode damages, and hold-off voltages are accurately determined.

Experimental and analytical studies of advanced air cushion landing systems

NASA Technical Reports Server (NTRS)

Lee, E. G. S.; Boghani, A. B.; Captain, K. M.; Rutishauser, H. J.; Farley, H. L.; Fish, R. B.; Jeffcoat, R. L.

1981-01-01

Several concepts are developed for air cushion landing systems (ACLS) which have the potential for improving performance characteristics (roll stiffness, heave damping, and trunk flutter), and reducing fabrication cost and complexity. After an initial screening, the following five concepts were evaluated in detail: damped trunk, filled trunk, compartmented trunk, segmented trunk, and roll feedback control. The evaluation was based on tests performed on scale models. An ACLS dynamic simulation developed earlier is updated so that it can be used to predict the performance of full-scale ACLS incorporating these refinements. The simulation was validated through scale-model tests. A full-scale ACLS based on the segmented trunk concept was fabricated and installed on the NASA ACLS test vehicle, where it is used to support advanced system development. A geometrically-scaled model (one third full scale) of the NASA test vehicle was fabricated and tested. This model, evaluated by means of a series of static and dynamic tests, is used to investigate scaling relationships between reduced and full-scale models. The analytical model developed earlier is applied to simulate both the one third scale and the full scale response.

Antecedents and consequences of psychological and team empowerment in organizations: a meta-analytic review.

PubMed

Seibert, Scott E; Wang, Gang; Courtright, Stephen H

2011-09-01

This paper provides meta-analytic support for an integrated model specifying the antecedents and consequences of psychological and team empowerment. Results indicate that contextual antecedent constructs representing perceived high-performance managerial practices, socio-political support, leadership, and work characteristics are each strongly related to psychological empowerment. Positive self-evaluation traits are related to psychological empowerment and are as strongly related as the contextual factors. Psychological empowerment is in turn positively associated with a broad range of employee outcomes, including job satisfaction, organizational commitment, and task and contextual performance, and is negatively associated with employee strain and turnover intentions. Team empowerment is positively related to team performance. Further, the magnitude of parallel antecedent and outcome relationships at the individual and team levels is statistically indistinguishable, demonstrating the generalizability of empowerment theory across these 2 levels of analysis. A series of analyses also demonstrates the validity of psychological empowerment as a unitary second-order construct. Implications and future directions for empowerment research and theory are discussed. PsycINFO Database Record (c) 2011 APA, all rights reserved

Time-dependent inertia analysis of vehicle mechanisms

NASA Astrophysics Data System (ADS)

Salmon, James Lee

Two methods for performing transient inertia analysis of vehicle hardware systems are developed in this dissertation. The analysis techniques can be used to predict the response of vehicle mechanism systems to the accelerations associated with vehicle impacts. General analytical methods for evaluating translational or rotational system dynamics are generated and evaluated for various system characteristics. The utility of the derived techniques are demonstrated by applying the generalized methods to two vehicle systems. Time dependent acceleration measured during a vehicle to vehicle impact are used as input to perform a dynamic analysis of an automobile liftgate latch and outside door handle. Generalized Lagrange equations for a non-conservative system are used to formulate a second order nonlinear differential equation defining the response of the components to the transient input. The differential equation is solved by employing the fourth order Runge-Kutta method. The events are then analyzed using commercially available two dimensional rigid body dynamic analysis software. The results of the two analytical techniques are compared to experimental data generated by high speed film analysis of tests of the two components performed on a high G acceleration sled at Ford Motor Company.

Aerosol-based detectors for liquid chromatography.

PubMed

Magnusson, Lars-Erik; Risley, Donald S; Koropchak, John A

2015-11-20

Aerosol-based detectors developed within the last few decades have increasingly addressed the need for sensitive, universal liquid chromatography detection in a wide variety of applications. Herein, we review the operating principles, instrumentation, analytical characteristics, and recent applications of the three general types of such detectors: evaporative light scattering detection (ELSD), condensation nucleation light scattering detection (CNLSD); commercially known as the nano-quantity analyte detector (NQAD), and charged aerosol detection (CAD). Included is a comparative evaluation of the operational and analytical characteristics of these detectors. Copyright © 2015 Elsevier B.V. All rights reserved.

Big Data Analytics in Medicine and Healthcare.

PubMed

Ristevski, Blagoj; Chen, Ming

2018-05-10

This paper surveys big data with highlighting the big data analytics in medicine and healthcare. Big data characteristics: value, volume, velocity, variety, veracity and variability are described. Big data analytics in medicine and healthcare covers integration and analysis of large amount of complex heterogeneous data such as various - omics data (genomics, epigenomics, transcriptomics, proteomics, metabolomics, interactomics, pharmacogenomics, diseasomics), biomedical data and electronic health records data. We underline the challenging issues about big data privacy and security. Regarding big data characteristics, some directions of using suitable and promising open-source distributed data processing software platform are given.

The Effect of Ice Formations on Propeller Performance

NASA Technical Reports Server (NTRS)

Neel, C. B., Jr.; Bright, L. G.

1950-01-01

Measurements of propeller efficiency loss due to ice formation are supplemented by an analysis to establish the magnitude of efficiency losses to be anticipated during flight in icing conditions. The measurements were made during flight in natural icing conditions; whereas the analysis consisted of an investIgation of changes in blade-section aerodynamic characteristics caused by ice formation and the resulting propeller efficiency changes. Agreement in the order of magnitude of eff 1- ciency losses to be expected is obtained between measured and analytical results. The results indicate that, in general, efficiency losses can be expected to be less than 10 percent; whereas maximum losses, which will be encountered only rarely, may be as high as 15 or 20 percent. Reported. losses larger than 15 or 20 percent, based on reductions in airplane performance, probably are due to ice accretions on other parts of the airplane. Blade-element theory is used in the analytical treatment, and calculations are made to show the degree to which the aerodynamic characteristics of a blade section. must be altered to produce various propeller efficiency losses. The effects of ice accretions on airfoil-section characteristics at subcritical speeds and their influence on drag-divergence Mach number are examined, and. the attendant maximum efficiency losses are computed. The effect of kinetic heating on the radial extent of ice formation is considered, and its influence on required length of blade heating shoes is discussed. It is demonstrated how the efficiency loss resulting from an icing encounter is influenced by the decisions of the pilot in adjusting the engine and propeller controls.

NASTRAN analysis of the 1/8-scale space shuttle dynamic model

NASA Technical Reports Server (NTRS)

Bernstein, M.; Mason, P. W.; Zalesak, J.; Gregory, D. J.; Levy, A.

1973-01-01

The space shuttle configuration has more complex structural dynamic characteristics than previous launch vehicles primarily because of the high model density at low frequencies and the high degree of coupling between the lateral and longitudinal motions. An accurate analytical representation of these characteristics is a primary means for treating structural dynamics problems during the design phase of the shuttle program. The 1/8-scale model program was developed to explore the adequacy of available analytical modeling technology and to provide the means for investigating problems which are more readily treated experimentally. The basic objectives of the 1/8-scale model program are: (1) to provide early verification of analytical modeling procedures on a shuttle-like structure, (2) to demonstrate important vehicle dynamic characteristics of a typical shuttle design, (3) to disclose any previously unanticipated structural dynamic characteristics, and (4) to provide for development and demonstration of cost effective prototype testing procedures.

Descriptive analysis of viral meningitis in a general hospital: differences in the characteristics between children and adults.

PubMed

Jiménez Caballero, P E; Muñoz Escudero, F; Murcia Carretero, S; Verdú Pérez, A

2011-10-01

our study aims to identify the clinical and epidemiological characteristics of viral meningitis in our environment and observe the differences with age. retrospective study of viral meningitis that required admission to our hospital between 2000 and 2008. We compare characteristics between groups of children (under 15 years) and adults (15 years or older). Results. The viral meningitis prevalent in males, is higher during the summer months and the agent most involved is enterovirus. Children are seen in the hospital with shorter time of onset and their average stay is less. In children, the analytical data show greater systemic disorder, whilst in adults the in the cerebrospinal fluid anomalies are more important. the viral meningitis in our environment is more common in males and in summer months. The clinical presentation and prodrome is similar in children and adults, although the average hospital stay is less in children of this age probably because the clinical outcome is shorter. The analytical data show that children have a higher systemic inflammation but lower CSF level, probably because lumbar puncture is performed earlier than in adults. Enteroviruses are common pathogens in both children and adults. Copyright © 2010 Sociedad Española de Neurología. Published by Elsevier Espana. All rights reserved.

Preparing Earth Data Scientists for 'the sexiest job of the 21st century'

NASA Astrophysics Data System (ADS)

Kempler, S. J.

2014-12-01

What Exactly do Earth Data Scientists do, and What do They Need to Know, to do It? There is not one simple answer, but there are many complex answers. Data Science, and data analytics, are new and nebulas, and takes on different characteristics depending on: The subject matter being analyzed, the maturity of the research, and whether the employed subject specific analytics is descriptive, diagnostic, discoveritive, predictive, or prescriptive, in nature. In addition, in a, thus far, business driven paradigm shift, university curriculums teaching data analytics pertaining to Earth science have, as a whole, lagged behind, and/or have varied in approach. This presentation attempts to breakdown and identify the many activities that Earth Data Scientists, as a profession, encounter, as well as provide case studies of specific Earth Data Scientist and data analytics efforts. I will also address the educational preparation, that best equips future Earth Data Scientists, needed to further Earth science heterogeneous data research and applications analysis. The goal of this presentation is to describe the actual need for Earth Data Scientists and the practical skills to perform Earth science data analytics, thus hoping to initiate discussion addressing a baseline set of needed expertise for educating future Earth Data Scientists.

Extended performance solar electric propulsion thrust system study. Volume 5. Capacitor-diode voltage multiplier: Technology evaluation

NASA Technical Reports Server (NTRS)

Martinelli, R. M.

1977-01-01

A 1-kW capacitor-diode voltage multiplier (CDVM) was designed, fabricated and tested to demonstrate the power of feasibility of high power CDVM's and to verify the analytical techniques that had been used to predict the performance characteristics of a 6-kw CDVM. High efficiency (96.2%), a low ratio of component weight to power (0.55 kg/kW), and low output ripple voltage (less than 1%, peak to peak) were obtained during the operation of a 1-kW CDVM various input line, load current, and load fault conditions.

A General Model for Performance Evaluation in DS-CDMA Systems with Variable Spreading Factors

NASA Astrophysics Data System (ADS)

Chiaraluce, Franco; Gambi, Ennio; Righi, Giorgia

This paper extends previous analytical approaches for the study of CDMA systems to the relevant case of multipath environments where users can operate at different bit rates. This scenario is of interest for the Wideband CDMA strategy employed in UMTS, and the model permits the performance comparison of classic and more innovative spreading signals. The method is based on the characteristic function approach, that allows to model accurately the various kinds of interferences. Some numerical examples are given with reference to the ITU-R M. 1225 Recommendations, but the analysis could be extended to different channel descriptions.

ATAMM enhancement and multiprocessing performance evaluation

NASA Technical Reports Server (NTRS)

Stoughton, John W.

1994-01-01

The algorithm to architecture mapping model (ATAAM) is a Petri net based model which provides a strategy for periodic execution of a class of real-time algorithms on multicomputer dataflow architecture. The execution of large-grained, decision-free algorithms on homogeneous processing elements is studied. The ATAAM provides an analytical basis for calculating performance bounds on throughput characteristics. Extension of the ATAMM as a strategy for cyclo-static scheduling provides for a truly distributed ATAMM multicomputer operating system. An ATAAM testbed consisting of a centralized graph manager and three processors is described using embedded firmware on 68HC11 microcontrollers.

A self-powered biosensing device with an integrated hybrid biofuel cell for intermittent monitoring of analytes.

PubMed

Majdecka, Dominika; Draminska, Sylwia; Janusek, Dariusz; Krysinski, Paweł; Bilewicz, Renata

2018-04-15

In this work, we propose an integrated self-powered sensing system, driven by a hybrid biofuel cell (HBFC) with carbon paper discs coated with multiwalled carbon nanotubes. The sensing system has a biocathode made from laccase or bilirubin oxidase, and the anode is made from a zinc plate. The system includes a dedicated custom-built electronic control unit for the detection of oxygen and catechol analytes, which are central to medical and environmental applications. Both the HBFC and sensors, operate in a mediatorless direct electron transfer mode. The measured characteristics of the HBFC with externally applied resistance included the power-time dependencies under flow cell conditions, the sensors performance (evaluated by cyclic voltammetry), and chronoamperometry. The HBFC is integrated with analytical devices and operating in a pulse mode form long-run monitoring experiments. The HBFC generated sufficient power for wireless data transmission to a local computer. Copyright © 2017 Elsevier B.V. All rights reserved.

Conceptual data sampling for breast cancer histology image classification.

PubMed

Rezk, Eman; Awan, Zainab; Islam, Fahad; Jaoua, Ali; Al Maadeed, Somaya; Zhang, Nan; Das, Gautam; Rajpoot, Nasir

2017-10-01

Data analytics have become increasingly complicated as the amount of data has increased. One technique that is used to enable data analytics in large datasets is data sampling, in which a portion of the data is selected to preserve the data characteristics for use in data analytics. In this paper, we introduce a novel data sampling technique that is rooted in formal concept analysis theory. This technique is used to create samples reliant on the data distribution across a set of binary patterns. The proposed sampling technique is applied in classifying the regions of breast cancer histology images as malignant or benign. The performance of our method is compared to other classical sampling methods. The results indicate that our method is efficient and generates an illustrative sample of small size. It is also competing with other sampling methods in terms of sample size and sample quality represented in classification accuracy and F1 measure. Copyright © 2017 Elsevier Ltd. All rights reserved.

Strategies for Dealing with Missing Data in Clinical Trials: From Design to Analysis

PubMed Central

Dziura, James D.; Post, Lori A.; Zhao, Qing; Fu, Zhixuan; Peduzzi, Peter

2013-01-01

Randomized clinical trials are the gold standard for evaluating interventions as randomized assignment equalizes known and unknown characteristics between intervention groups. However, when participants miss visits, the ability to conduct an intent-to-treat analysis and draw conclusions about a causal link is compromised. As guidance to those performing clinical trials, this review is a non-technical overview of the consequences of missing data and a prescription for its treatment beyond the typical analytic approaches to the entire research process. Examples of bias from incorrect analysis with missing data and discussion of the advantages/disadvantages of analytic methods are given. As no single analysis is definitive when missing data occurs, strategies for its prevention throughout the course of a trial are presented. We aim to convey an appreciation for how missing data influences results and an understanding of the need for careful consideration of missing data during the design, planning, conduct, and analytic stages. PMID:24058309

Analysis of polymeric phenolics in red wines using different techniques combined with gel permeation chromatography fractionation.

PubMed

Guadalupe, Zenaida; Soldevilla, Alberto; Sáenz-Navajas, María-Pilar; Ayestarán, Belén

2006-04-21

A multiple-step analytical method was developed to improve the analysis of polymeric phenolics in red wines. With a common initial step based on the fractionation of wine phenolics by gel permeation chromatography (GPC), different analytical techniques were used: high-performance liquid chromatography-diode array detection (HPLC-DAD), HPLC-mass spectrometry (MS), capillary zone electrophoresis (CZE) and spectrophotometry. This method proved to be valid for analyzing different families of phenolic compounds, such as monomeric phenolics and their derivatives, polymeric pigments and proanthocyanidins. The analytical characteristics of fractionation by GPC were studied and the method was fully validated, yielding satisfactory statistical results. GPC fractionation substantially improved the analysis of polymeric pigments by CZE, in terms of response, repeatability and reproducibility. It also represented an improvement in the traditional vanillin assay used for proanthocyanidin (PA) quantification. Astringent proanthocyanidins were also analyzed using a simple combined method that allowed these compounds, for which only general indexes were available, to be quantified.

A Proposed Method to Predict Preterm Birth Using Clinical Data, Standard Maternal Serum Screening, and Cholesterol

PubMed Central

ALLEMAN, Brandon W.; SMITH, Amanda R.; BYERS, Heather M.; BEDELL, Bruce; RYCKMAN, Kelli K.; MURRAY, Jeffrey C.; BOROWSKI, Kristi S.

2013-01-01

Objective To create a predictive model for preterm birth (PTB) from available clinical data and serum analytes. Study Design Serum analytes, routine pregnancy screening plus cholesterol and corresponding health information were linked to birth certificate data for a cohort of 2699 Iowa women with serum sampled in the first and second trimester. Stepwise logistic regression was used to select the best predictive model for PTB. Results Serum screening markers remained significant predictors of PTB even after controlling for maternal characteristics. The best predictive model included maternal characteristics, first trimester total cholesterol (TC), TC change between trimesters and second trimester alpha-fetoprotein and inhibin A. The model showed better discriminatory ability than PTB history alone and performed similarly in subgroups of women without past PTB. Conclusions Using clinical and serum screening data a potentially useful predictor of PTB was constructed. Validation and replication in other populations, and incorporation of other measures that identify PTB risk, like cervical length, can be a step towards identifying additional women who may benefit from new or currently available interventions. PMID:23500456

A correlative study between analysis and experiment on the fracture behavior of graphite/epoxy composites

NASA Technical Reports Server (NTRS)

Yeow, Y. T.; Morris, D. H.; Brinson, H. F.

1979-01-01

The paper compares the fracture behavior of a composite material by using the analytical models of Waddoups et al. (1971), Whitney and Nuismer (1974, 1975), and Snyder and Cruse (1975) with experimental results from tests performed on center-notched tensile strips. Laminate configurations of (0 deg)8s, (0 deg/90 deg)4s, (+ and -45 deg)4s, and (0 deg/+ and -45 deg/0 deg)2s from T300/934 graphite/epoxy are tested. These particular configurations are used so that the effect of various degrees of anisotropy can be studied. The procedure adopted uses the results from one test for crack size aspect ratio to predict the results of tests of other aspect ratios. For those methods that use a characteristic dimension, predictions are made by assuming the magnitude of this dimension to be constant. The validity of this assumption for a laminate is assessed by comparing predicted and experimental results. Analytical models using a characteristic dimension are compared to the model developed by Cruse (1973).

[A governance approach applied to analysing research into unemployed workers in the city of Medellin in Colombia].

PubMed

Cardona, Alvaro; Nieto, Emmanuel; Mejía, Luz M

2010-01-01

Performing an academic exercise aimed at applying the analytical categories from the governance approach developed by Marc Hufty et al., to understand social actors’ relationships in an investigation and intervention project studying so-cioeconomic conditions and seeking to guarantee health insurance continuity for those workers who had lost their work in the city of Medellin, Colombia, from 2004 to 2007. A process of investigation and intervention was examined as a casestudy in which researchers were one of the actors so involved. Characterising stake-holders included: their level of inclusion/involvement in the problem; their power for influencing public policy proposals; their perceptions and proposals’ characteristics, power and dynamics regarding the problem of unemployment and health insurance when someone has lost her/his work; and the characteristics of their interaction with other actors. The results showed that the four analytical dimensions proposed by Hufty (actors, social norms, nodal points and processes) were useful for describing and understanding the interaction of the actors involved in the research and intervention proposal being analysed here (i.e. the case-study). It was concluded that the analytical governance framework proposed by Hufty was useful for understanding how the social subjects interacted; these were the rules which were taken for describing their interaction, being the most important nodes for interaction and progresses achieved whilst implementing the intervention proposal.

Alternative outcome definitions and their effect on the performance of methods for observational outcome studies.

PubMed

Reich, Christian G; Ryan, Patrick B; Schuemie, Martijn J

2013-10-01

A systematic risk identification system has the potential to test marketed drugs for important Health Outcomes of Interest or HOI. For each HOI, multiple definitions are used in the literature, and some of them are validated for certain databases. However, little is known about the effect of different definitions on the ability of methods to estimate their association with medical products. Alternative definitions of HOI were studied for their effect on the performance of analytical methods in observational outcome studies. A set of alternative definitions for three HOI were defined based on literature review and clinical diagnosis guidelines: acute kidney injury, acute liver injury and acute myocardial infarction. The definitions varied by the choice of diagnostic codes and the inclusion of procedure codes and lab values. They were then used to empirically study an array of analytical methods with various analytical choices in four observational healthcare databases. The methods were executed against predefined drug-HOI pairs to generate an effect estimate and standard error for each pair. These test cases included positive controls (active ingredients with evidence to suspect a positive association with the outcome) and negative controls (active ingredients with no evidence to expect an effect on the outcome). Three different performance metrics where used: (i) Area Under the Receiver Operator Characteristics (ROC) curve (AUC) as a measure of a method's ability to distinguish between positive and negative test cases, (ii) Measure of bias by estimation of distribution of observed effect estimates for the negative test pairs where the true effect can be assumed to be one (no relative risk), and (iii) Minimal Detectable Relative Risk (MDRR) as a measure of whether there is sufficient power to generate effect estimates. In the three outcomes studied, different definitions of outcomes show comparable ability to differentiate true from false control cases (AUC) and a similar bias estimation. However, broader definitions generating larger outcome cohorts allowed more drugs to be studied with sufficient statistical power. Broader definitions are preferred since they allow studying drugs with lower prevalence than the more precise or narrow definitions while showing comparable performance characteristics in differentiation of signal vs. no signal as well as effect size estimation.

Infiltrated photonic crystal cavity as a highly sensitive platform for glucose concentration detection

NASA Astrophysics Data System (ADS)

Arafa, Safia; Bouchemat, Mohamed; Bouchemat, Touraya; Benmerkhi, Ahlem; Hocini, Abdesselam

2017-02-01

A Bio-sensing platform based on an infiltrated photonic crystal ring shaped holes cavity-coupled waveguide system is proposed for glucose concentration detection. Considering silicon-on-insulator (SOI) technology, it has been demonstrated that the ring shaped holes configuration provides an excellent optical confinement within the cavity region, which further enhances the light-matter interactions at the precise location of the analyte medium. Thus, the sensitivity and the quality factor (Q) can be significantly improved. The transmission characteristics of light in the biosensor under different refractive indices that correspond to the change in the analyte glucose concentration are analyzed by performing finite-difference time-domain (FDTD) simulations. Accordingly, an improved sensitivity of 462 nm/RIU and a Q factor as high as 1.11х105 have been achieved, resulting in a detection limit of 3.03х10-6 RIU. Such combination of attributes makes the designed structure a promising element for performing label-free biosensing in medical diagnosis and environmental monitoring.

Digital mammographic tumor classification using transfer learning from deep convolutional neural networks.

PubMed

Huynh, Benjamin Q; Li, Hui; Giger, Maryellen L

2016-07-01

Convolutional neural networks (CNNs) show potential for computer-aided diagnosis (CADx) by learning features directly from the image data instead of using analytically extracted features. However, CNNs are difficult to train from scratch for medical images due to small sample sizes and variations in tumor presentations. Instead, transfer learning can be used to extract tumor information from medical images via CNNs originally pretrained for nonmedical tasks, alleviating the need for large datasets. Our database includes 219 breast lesions (607 full-field digital mammographic images). We compared support vector machine classifiers based on the CNN-extracted image features and our prior computer-extracted tumor features in the task of distinguishing between benign and malignant breast lesions. Five-fold cross validation (by lesion) was conducted with the area under the receiver operating characteristic (ROC) curve as the performance metric. Results show that classifiers based on CNN-extracted features (with transfer learning) perform comparably to those using analytically extracted features [area under the ROC curve [Formula: see text

Analytical Methods for Biomass Characterization during Pretreatment and Bioconversion

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

Pu, Yunqiao; Meng, Xianzhi; Yoo, Chang Geun

2016-01-01

Lignocellulosic biomass has been introduced as a promising resource for alternative fuels and chemicals because of its abundance and complement for petroleum resources. Biomass is a complex biopolymer and its compositional and structural characteristics largely vary depending on its species as well as growth environments. Because of complexity and variety of biomass, understanding its physicochemical characteristics is a key for effective biomass utilization. Characterization of biomass does not only provide critical information of biomass during pretreatment and bioconversion, but also give valuable insights on how to utilize the biomass. For better understanding biomass characteristics, good grasp and proper selection ofmore » analytical methods are necessary. This chapter introduces existing analytical approaches that are widely employed for biomass characterization during biomass pretreatment and conversion process. Diverse analytical methods using Fourier transform infrared (FTIR) spectroscopy, gel permeation chromatography (GPC), and nuclear magnetic resonance (NMR) spectroscopy for biomass characterization are reviewed. In addition, biomass accessibility methods by analyzing surface properties of biomass are also summarized in this chapter.« less

Statistically qualified neuro-analytic failure detection method and system

DOEpatents

Vilim, Richard B.; Garcia, Humberto E.; Chen, Frederick W.

2002-03-02

An apparatus and method for monitoring a process involve development and application of a statistically qualified neuro-analytic (SQNA) model to accurately and reliably identify process change. The development of the SQNA model is accomplished in two stages: deterministic model adaption and stochastic model modification of the deterministic model adaptation. Deterministic model adaption involves formulating an analytic model of the process representing known process characteristics, augmenting the analytic model with a neural network that captures unknown process characteristics, and training the resulting neuro-analytic model by adjusting the neural network weights according to a unique scaled equation error minimization technique. Stochastic model modification involves qualifying any remaining uncertainty in the trained neuro-analytic model by formulating a likelihood function, given an error propagation equation, for computing the probability that the neuro-analytic model generates measured process output. Preferably, the developed SQNA model is validated using known sequential probability ratio tests and applied to the process as an on-line monitoring system. Illustrative of the method and apparatus, the method is applied to a peristaltic pump system.

Enhanced performance of microfluidic soft pressure sensors with embedded solid microspheres

NASA Astrophysics Data System (ADS)

Shin, Hee-Sup; Ryu, Jaiyoung; Majidi, Carmel; Park, Yong-Lae

2016-02-01

The cross-sectional geometry of an embedded microchannel influences the electromechanical response of a soft microfluidic sensor to applied surface pressure. When a pressure is exerted on the surface of the sensor deforming the soft structure, the cross-sectional area of the embedded channel filled with a conductive fluid decreases, increasing the channel’s electrical resistance. This electromechanical coupling can be tuned by adding solid microspheres into the channel. In order to determine the influence of microspheres, we use both analytic and computational methods to predict the pressure responses of soft microfluidic sensors with two different channel cross-sections: a square and an equilateral triangular. The analytical models were derived from contact mechanics in which microspheres were regarded as spherical indenters, and finite element analysis (FEA) was used for simulation. For experimental validation, sensor samples with the two different channel cross-sections were prepared and tested. For comparison, the sensor samples were tested both with and without microspheres. All three results from the analytical models, the FEA simulations, and the experiments showed reasonable agreement confirming that the multi-material soft structure significantly improved its pressure response in terms of both linearity and sensitivity. The embedded solid particles enhanced the performance of soft sensors while maintaining their flexible and stretchable mechanical characteristic. We also provide analytical and experimental analyses of hysteresis of microfluidic soft sensors considering a resistive force to the shape recovery of the polymer structure by the embedded viscous fluid.

Combustion performance and heat transfer characterization of LOX/hydrocarbon type propellants

NASA Technical Reports Server (NTRS)

Michel, R. W.

1983-01-01

An evaluation liquid oxygen (LOX) and various hydrocarbon fuels as low cost alternative propellants suitable for future space transportation system applications was done. The emphasis was directed toward low earth orbit maneuvering engine and reaction control engine systems. The feasibility of regeneratively cooling an orbit maneuvering thruster was analytically determined over a range of operating conditions from 100 to 1000 psia chamber pressure and 1000 to 10,000-1bF thrust, and specific design points were analyzed in detail for propane, methane, RP-1, ammonia, and ethanol; similar design point studies were performed for a film-cooled reaction control thruster. Heat transfer characteristics of propane were experimentally evaluated in heated tube tests. Forced convection heat transfer coefficients were determined. Seventy-seven hot firing tests were conducted with LOX/propane and LOX/ethanol, for a total duration of nearly 1400 seconds, using both heat sink and water-cooled calorimetric chambers. Combustion performance and stability and gas-side heat transfer characteristics were evaluated.

Electric sail elliptic displaced orbits with advanced thrust model

NASA Astrophysics Data System (ADS)

Niccolai, Lorenzo; Quarta, Alessandro A.; Mengali, Giovanni

2017-09-01

This paper analyzes the performance of an Electric Solar Wind Sail for generating and maintaining an elliptic, heliocentric, displaced non-Keplerian orbit. In this sense, this paper extends and completes recent studies regarding the performances of an Electric Solar Wind Sail that covers a circular, heliocentric, displaced orbit of given characteristics. The paper presents the general equations that describe the elliptic orbit maintenance in terms of both spacecraft attitude and performance requirements, when a refined thrust model (recently proposed for the preliminary mission design) is taken into account. In particular, the paper also discusses some practical applications on particular mission scenarios in which an analytic solution of the governing equations has been found.

Heavy hydrocarbon main injector technology program

NASA Technical Reports Server (NTRS)

Arbit, H. A.; Tuegel, L. M.; Dodd, F. E.

1991-01-01

The Heavy Hydrocarbon Main Injector Program was an analytical, design, and test program to demonstrate an injection concept applicable to an Isolated Combustion Compartment of a full-scale, high pressure, LOX/RP-1 engine. Several injector patterns were tested in a 3.4-in. combustor. Based on these results, features of the most promising injector design were incorporated into a 5.7-in. injector which was then hot-fire tested. In turn, a preliminary design of a 5-compartment 2D combustor was based on this pattern. Also the additional subscale injector testing and analysis was performed with an emphasis on improving analytical techniques and acoustic cavity design methodology. Several of the existing 3.5-in. diameter injectors were hot-fire tested with and without acoustic cavities for spontaneous and dynamic stability characteristics.

Genetics-based methods for detection of Salmonella spp. in foods.

PubMed

Mozola, Mark A

2006-01-01

Genetic methods are now at the forefront of foodborne pathogen testing. The sensitivity, specificity, and inclusivity advantages offered by deoxyribonucleic acid (DNA) probe technology have driven an intense effort in methods development over the past 20 years. DNA probe-based methods for Salmonella spp. and other pathogens have progressed from time-consuming procedures involving the use of radioisotopes to simple, high throughput, automated assays. The analytical sensitivity of nucleic acid amplification technology has facilitated a reduction in analysis time by allowing enriched samples to be tested for previously undetectable quantities of analyte. This article will trace the evolution of the development of genetic methods for detection of Salmonella in foods, review the basic assay formats and their advantages and limitations, and discuss method performance characteristics and considerations for selection of methods.

Hypersonic research engine project. Phase 2: Aerothermodynamic integration model development, data item no. 55-4-21

NASA Technical Reports Server (NTRS)

Jilly, L. F. (Editor)

1975-01-01

The design and development of the Aerothermodynamic Integration Model (AIM) of the Hypersonic Research Engine (HRE) is described. The feasibility of integrating the various analytical and experimental data available for the design of the hypersonic ramjet engine was verified and the operational characteristic and the overall performance of the selected design was determined. The HRE-AIM was designed for operation at speeds of Mach 3 through Mach 8.

Optofluidic Microsystems for Chemical and Biological Analysis

PubMed Central

Fan, Xudong; White, Ian M.

2011-01-01

Optofluidics – the synergistic integration of photonics and microfluidics – has recently emerged as a new analytical field that provides a number of unique characteristics for enhanced sensing performance and simplification of microsystems. In this review, we describe various optofluidic architectures developed in the past five years, emphasize the mechanisms by which optofluidics enhances bio/chemical analysis capabilities, including sensing and the precise control of biological micro/nanoparticles, and envision new research directions to which optofluidics leads. PMID:22059090

Orbital Transfer Vehicle Engine Technology High Velocity Ratio Diffusing Crossover

NASA Technical Reports Server (NTRS)

Lariviere, Brian W.

1992-01-01

High speed, high efficiency head rise multistage pumps require continuous passage diffusing crossovers to effectively convey the pumped fluid from the exit of one impeller to the inlet of the next impeller. On Rocketdyne's Orbital Transfer Vehicle (OTV), the MK49-F, a three stage high pressure liquid hydrogen turbopump, utilizes a 6.23 velocity ratio diffusing crossover. This velocity ratio approaches the diffusion limits for stable and efficient flow over the operating conditions required by the OTV system. The design of the high velocity ratio diffusing crossover was based on advanced analytical techniques anchored by previous tests of stationary two-dimensional diffusers with steady flow. To secure the design and the analytical techniques, tests were required with the unsteady whirling characteristics produced by an impeller. A tester was designed and fabricated using a 2.85 times scale model of the MK49-F turbopumps first stage, including the inducer, impeller, and the diffusing crossover. Water and air tests were completed to evaluate the large scale turbulence, non-uniform velocity, and non-steady velocity on the pump and crossover head and efficiency. Suction performance tests from 80 percent to 124 percent of design flow were completed in water to assess these pump characteristics. Pump and diffuser performance from the water and air tests were compared with the actual MK49-F test data in liquid hydrogen.

Structural characterization of constituents with molecular diversity in fractions from Lysidice brevicalyx by liquid chromatography/diode-array detection/electrospray ionization tandem mass spectrometry and liquid chromatography/nuclear magnetic resonance.

PubMed

Qu, Jing; Hu, You-cai; Li, Jian-bei; Wang, Ying-hong; Zhang, Jin-lan; Abliz, Zeper; Yu, Shi-shan; Liu, Yun-bao

2008-01-01

A combination of electrospray ionization tandem mass spectrometry with high-performance liquid chromatography (HPLC/ESI-MSn), and hyphenation of liquid chromatography to nuclear magnetic resonance spectroscopy (HPLC/NMR), have been extensively utilized for on-line analysis of natural products, analyzing metabolite and drug impurity. In our last paper, we reported an on-line analytical method for structural identification of trace alkaloids in the same class. However, the structural types of the constituents in plants were various, such as flavanoids, terpenoids and steroids. It is important to establish an effective analytical method for on-line structural identification of constituents with molecular diversity in extracts of plants. So, in the present study, the fragmentation patterns of some isolated stilbenes, phloroglucinols and flavanoids from Lysidice rhodostegia were investigated by ESI-MSn. Their fragmentation rules and UV characteristics are summarized, and the relationship between the spectral characteristics, rules and the structures is described. According to the fragmentation rules, NMR and UV spectral characteristics, 24 constituents of different types in the fractions from L. brevicalyx of the same genus were structurally characterized on the basis of HPLC/HRMS, HPLC-UV/ESI-MSn, HPLC/1H NMR and HPLC/1H-1H COSY rapidly. Of these, six (10, 13, 14, 16, 17 and 23) are new compounds and all of them are reported from L. brevicalyx for the first time. The aim is to develop an effective analytical method for on-line structural identification of natural products with molecular diversity in plants, and to guide the rapid and direct isolation of novel compounds by chemical screening.

Developing semi-analytical solution for multiple-zone transient storage model with spatially non-uniform storage

NASA Astrophysics Data System (ADS)

Deng, Baoqing; Si, Yinbing; Wang, Jia

2017-12-01

Transient storages may vary along the stream due to stream hydraulic conditions and the characteristics of storage. Analytical solutions of transient storage models in literature didn't cover the spatially non-uniform storage. A novel integral transform strategy is presented that simultaneously performs integral transforms to the concentrations in the stream and in storage zones by using the single set of eigenfunctions derived from the advection-diffusion equation of the stream. The semi-analytical solution of the multiple-zone transient storage model with the spatially non-uniform storage is obtained by applying the generalized integral transform technique to all partial differential equations in the multiple-zone transient storage model. The derived semi-analytical solution is validated against the field data in literature. Good agreement between the computed data and the field data is obtained. Some illustrative examples are formulated to demonstrate the applications of the present solution. It is shown that solute transport can be greatly affected by the variation of mass exchange coefficient and the ratio of cross-sectional areas. When the ratio of cross-sectional areas is big or the mass exchange coefficient is small, more reaches are recommended to calibrate the parameter.

Analytical modeling and numerical simulation of the short-wave infrared electron-injection detectors

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

Movassaghi, Yashar; Fathipour, Morteza; Fathipour, Vala

2016-03-21

This paper describes comprehensive analytical and simulation models for the design and optimization of the electron-injection based detectors. The electron-injection detectors evaluated here operate in the short-wave infrared range and utilize a type-II band alignment in InP/GaAsSb/InGaAs material system. The unique geometry of detectors along with an inherent negative-feedback mechanism in the device allows for achieving high internal avalanche-free amplifications without any excess noise. Physics-based closed-form analytical models are derived for the detector rise time and dark current. Our optical gain model takes into account the drop in the optical gain at high optical power levels. Furthermore, numerical simulation studiesmore » of the electrical characteristics of the device show good agreement with our analytical models as well experimental data. Performance comparison between devices with different injector sizes shows that enhancement in the gain and speed is anticipated by reducing the injector size. Sensitivity analysis for the key detector parameters shows the relative importance of each parameter. The results of this study may provide useful information and guidelines for development of future electron-injection based detectors as well as other heterojunction photodetectors.« less

How Can Visual Analytics Assist Investigative Analysis? Design Implications from an Evaluation.

PubMed

Youn-Ah Kang; Görg, Carsten; Stasko, John

2011-05-01

Despite the growing number of systems providing visual analytic support for investigative analysis, few empirical studies of the potential benefits of such systems have been conducted, particularly controlled, comparative evaluations. Determining how such systems foster insight and sensemaking is important for their continued growth and study, however. Furthermore, studies that identify how people use such systems and why they benefit (or not) can help inform the design of new systems in this area. We conducted an evaluation of the visual analytics system Jigsaw employed in a small investigative sensemaking exercise, and compared its use to three other more traditional methods of analysis. Sixteen participants performed a simulated intelligence analysis task under one of the four conditions. Experimental results suggest that Jigsaw assisted participants to analyze the data and identify an embedded threat. We describe different analysis strategies used by study participants and how computational support (or the lack thereof) influenced the strategies. We then illustrate several characteristics of the sensemaking process identified in the study and provide design implications for investigative analysis tools based thereon. We conclude with recommendations on metrics and techniques for evaluating visual analytics systems for investigative analysis.

A systematic investigation of sample diluents in modern supercritical fluid chromatography.

PubMed

Desfontaine, Vincent; Tarafder, Abhijit; Hill, Jason; Fairchild, Jacob; Grand-Guillaume Perrenoud, Alexandre; Veuthey, Jean-Luc; Guillarme, Davy

2017-08-18

This paper focuses on the possibility to inject large volumes (up to 10μL) in ultra-high performance supercritical fluid chromatography (UHPSFC) under generic gradient conditions. Several injection and method parameters have been individually evaluated (i.e. analyte concentration, injection volume, initial percentage of co-solvent in the gradient, nature of the weak needle wash solvent, nature of the sample diluent, nature of the column and of the analyte). The most critical parameters were further investigated using in a multivariate approach. The overall results suggested that several aprotic solvents including methyl tert-butyl ether (MTBE), dichloromethane, acetonitrile or cyclopentyl methyl ether (CPME) were well adapted for the injection of large volume in UHPSFC, while MeOH was generally the worst alternative. However, the nature of the stationary phase also had a strong impact and some of these diluents did not perform equally on each column. This was due to the existence of a competition in the adsorption of the analyte and the diluent on the stationary phase. This observation introduced the idea that the sample diluent should not only be chosen according to the analyte but also to the column chemistry to limit the interactions between the diluent and the ligands. Other important characteristics of the "ideal" SFC sample diluent were finally highlighted. Aprotic solvents with low viscosity are preferable to avoid strong solvent effects and viscous fingering, respectively. In the end, the authors suggest that the choice of the sample diluent should be part of the method development, as a function of the analyte and the selected stationary phase. Copyright © 2017 Elsevier B.V. All rights reserved.

Magnetic molecularly imprinted polymers for the determination of β-agonist residues in milk by ultra high performance liquid chromatography with tandem mass spectrometry.

PubMed

Liu, Hongcheng; Lin, Xin; Lin, Tao; Zhang, Yulong; Luo, Yinglan; Li, Qiwan

2016-09-01

A simple, accurate, and highly sensitive analytical method was developed in this study for the determination of nine β-agonists in milk. In this method, a new magnetic adsorbent of molecularly imprinted polymers/magnetic nanoparticles prepared by simple physical blending was adopted, which enabled magnetic solid-phase extraction. Thus, the resultant material can be separated from the solvent rapidly and conveniently by a magnet. Two kinds of molecularly imprinted polymer/magnetic nanoparticles materials were fabricated, and the characteristics of materials such as the ratio, pH, amount, desorption, and regeneration were investigated. The analytes were quantified by ultra high performance liquid chromatography coupled to an electrospray ionization tandem mass spectrometer operating in multiple reaction monitoring modes. The detection limit of the method was 0.003-0.3 μg/L, and the detection capability was 0.01-0.3 μg/L. The recoveries of these compounds were 65.7-114% at three spiked levels. Reproducibility represented by relative standard deviation was 11.2% or less. The method was successfully applied to the screening of real samples obtained from local markets and confirmation of the suspected target analytes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Impact of Recent Hardware and Software Trends on High Performance Transaction Processing and Analytics

NASA Astrophysics Data System (ADS)

Mohan, C.

In this paper, I survey briefly some of the recent and emerging trends in hardware and software features which impact high performance transaction processing and data analytics applications. These features include multicore processor chips, ultra large main memories, flash storage, storage class memories, database appliances, field programmable gate arrays, transactional memory, key-value stores, and cloud computing. While some applications, e.g., Web 2.0 ones, were initially built without traditional transaction processing functionality in mind, slowly system architects and designers are beginning to address such previously ignored issues. The availability, analytics and response time requirements of these applications were initially given more importance than ACID transaction semantics and resource consumption characteristics. A project at IBM Almaden is studying the implications of phase change memory on transaction processing, in the context of a key-value store. Bitemporal data management has also become an important requirement, especially for financial applications. Power consumption and heat dissipation properties are also major considerations in the emergence of modern software and hardware architectural features. Considerations relating to ease of configuration, installation, maintenance and monitoring, and improvement of total cost of ownership have resulted in database appliances becoming very popular. The MapReduce paradigm is now quite popular for large scale data analysis, in spite of the major inefficiencies associated with it.

Hasse diagram as a green analytical metrics tool: ranking of methods for benzo[a]pyrene determination in sediments.

PubMed

Bigus, Paulina; Tsakovski, Stefan; Simeonov, Vasil; Namieśnik, Jacek; Tobiszewski, Marek

2016-05-01

This study presents an application of the Hasse diagram technique (HDT) as the assessment tool to select the most appropriate analytical procedures according to their greenness or the best analytical performance. The dataset consists of analytical procedures for benzo[a]pyrene determination in sediment samples, which were described by 11 variables concerning their greenness and analytical performance. Two analyses with the HDT were performed-the first one with metrological variables and the second one with "green" variables as input data. Both HDT analyses ranked different analytical procedures as the most valuable, suggesting that green analytical chemistry is not in accordance with metrology when benzo[a]pyrene in sediment samples is determined. The HDT can be used as a good decision support tool to choose the proper analytical procedure concerning green analytical chemistry principles and analytical performance merits.

Analytical description of the modern steam automobile

NASA Technical Reports Server (NTRS)

Peoples, J. A.

1974-01-01

The sensitivity of operating conditions upon performance of the modern steam automobile is discussed. The word modern has been used in the title to indicate that emphasis is upon miles per gallon rather than theoretical thermal efficiency. This has been accomplished by combining classical power analysis with the ideal Pressure-Volume diagram. Several parameters are derived which characterize performance capability of the modern steam car. The report illustrates that performance is dictated by the characteristics of the working medium, and the supply temperature. Performance is nearly independent of pressures above 800 psia. Analysis techniques were developed specifically for reciprocating steam engines suitable for automotive application. Specific performance charts have been constructed on the basis of water as a working medium. The conclusions and data interpretation are therefore limited within this scope.

Network-Cognizant Design of Decentralized Volt/VAR Controllers

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

Baker, Kyri A; Bernstein, Andrey; Zhao, Changhong

This paper considers the problem of designing decentralized Volt/VAR controllers for distributed energy resources (DERs). The voltage-reactive power characteristics of individual DERs are obtained by solving a convex optimization problem, where given performance objectives (e.g., minimization of the voltage deviations from a given profile) are specified and stability constraints are enforced. The resultant Volt/VAR characteristics are network-cognizant, in the sense that they embed information on the location of the DERs and, consequently, on the effect of reactive-power adjustments on the voltages throughout the feeder. Bounds on the maximum voltage deviation incurred by the controllers are analytically established. Numerical results aremore » reported to corroborate the technical findings.« less

Micromotors with Step-Motor Characteristics by Controlled Magnetic Interactions among Assembled Components

PubMed Central

2015-01-01

In this study, we investigated the control of the rotation dynamics of an innovative type of rotary micromotors with desired performances by tuning the magnetic interactions among the assembled micro/nanoscale components. The micromotors are made of metallic nanowires as rotors, patterned magnetic nanodisks as bearings and actuated by external electric fields. The magnetic forces for anchoring the rotors on the bearings play an essential role in the rotation dynamics of the micromotors. By varying the moment, orientation, and dimension of the magnetic components, distinct rotation behaviors can be observed, including repeatable wobbling and rolling in addition to rotation. We understood the rotation behaviors by analytical modeling, designed and realized micromotors with step-motor characteristics. The outcome of this research could inspire the development of high-performance nanomachines assembled from synthetic nanoentities, relevant to nanorobotics, microfluidics, and biomedical research. PMID:25536023

Parametric analyses of planned flowing uranium hexafluoride critical experiments

NASA Technical Reports Server (NTRS)

Rodgers, R. J.; Latham, T. S.

1976-01-01

Analytical investigations were conducted to determine preliminary design and operating characteristics of flowing uranium hexafluoride (UF6) gaseous nuclear reactor experiments in which a hybrid core configuration comprised of UF6 gas and a region of solid fuel will be employed. The investigations are part of a planned program to perform a series of experiments of increasing performance, culminating in an approximately 5 MW fissioning uranium plasma experiment. A preliminary design is described for an argon buffer gas confined, UF6 flow loop system for future use in flowing critical experiments. Initial calculations to estimate the operating characteristics of the gaseous fissioning UF6 in a confined flow test at a pressure of 4 atm, indicate temperature increases of approximately 100 and 1000 K in the UF6 may be obtained for total test power levels of 100 kW and 1 MW for test times of 320 and 32 sec, respectively.

Dynamic characteristics of stay cables with inerter dampers

NASA Astrophysics Data System (ADS)

Shi, Xiang; Zhu, Songye

2018-06-01

This study systematically investigates the dynamic characteristics of a stay cable with an inerter damper installed close to one end of a cable. The interest in applying inerter dampers to stay cables is partially inspired by the superior damping performance of negative stiffness dampers in the same application. A comprehensive parametric study on two major parameters, namely, inertance and damping coefficients, are conducted using analytical and numerical approaches. An inerter damper can be optimized for one vibration mode of a stay cable by generating identical wave numbers in two adjacent modes. An optimal design approach is proposed for inerter dampers installed on stay cables. The corresponding optimal inertance and damping coefficients are summarized for different damper locations and interested modes. Inerter dampers can offer better damping performance than conventional viscous dampers for the target mode of a stay cable that requires optimization. However, additional damping ratios in other vibration modes through inerter damper are relatively limited.

A rapid method for optimization of the rocket propulsion system for single-stage-to-orbit vehicles

NASA Technical Reports Server (NTRS)

Eldred, C. H.; Gordon, S. V.

1976-01-01

A rapid analytical method for the optimization of rocket propulsion systems is presented for a vertical take-off, horizontal landing, single-stage-to-orbit launch vehicle. This method utilizes trade-offs between propulsion characteristics affecting flight performance and engine system mass. The performance results from a point-mass trajectory optimization program are combined with a linearized sizing program to establish vehicle sizing trends caused by propulsion system variations. The linearized sizing technique was developed for the class of vehicle systems studied herein. The specific examples treated are the optimization of nozzle expansion ratio and lift-off thrust-to-weight ratio to achieve either minimum gross mass or minimum dry mass. Assumed propulsion system characteristics are high chamber pressure, liquid oxygen and liquid hydrogen propellants, conventional bell nozzles, and the same fixed nozzle expansion ratio for all engines on a vehicle.

On-orbit experience with the HEAO attitude control subsystem

NASA Technical Reports Server (NTRS)

Hoffman, D. P.; Berkery, E. A.

1978-01-01

The first satellite (HEAO-1) in the High Energy Astronomy Observatory Program series was launched successfully on Aug. 12, 1977. To date it has completed over nine months of orbital operation in a science data gathering mode. During this period all attitude control modes have been exercised and all primary mission objectives have been achieved. This paper highlights the characteristics of the attitude control subsystem design and compares the predicted performance with the actual flight operations experience. Environmental disturbance modeling, component hardware/software characteristics, and overall attitude control performance are reviewed and are found to compare very well with the prelaunch analytical predictions. Brief comments are also included regarding the operations aspects of the attitude control subsystem. The experience in this regard demonstrates the effectiveness of the design flexibility afforded by the presence of a general purpose digital processor in the subsystem flight hardware implementation.

An Analytical Hierarchy Process Model for the Evaluation of College Experimental Teaching Quality

ERIC Educational Resources Information Center

Yin, Qingli

2013-01-01

Taking into account the characteristics of college experimental teaching, through investigaton and analysis, evaluation indices and an Analytical Hierarchy Process (AHP) model of experimental teaching quality have been established following the analytical hierarchy process method, and the evaluation indices have been given reasonable weights. An…

The effect of air entrapment on the performance of squeeze film dampers: Experiments and analysis

NASA Astrophysics Data System (ADS)

Diaz Briceno, Sergio Enrique

Squeeze film dampers (SFDs) are an effective means to introduce the required damping in rotor-bearing systems. They are a standard application in jet engines and are commonly used in industrial compressors. Yet, lack of understanding of their operation has confined the design of SFDs to a costly trial and error process based on prior experience. The main factor deterring the success of analytical models for the prediction of SFDs' performance lays on the modeling of the dynamic film rupture. Usually, the cavitation models developed for journal bearings are applied to SFDs. Yet, the characteristic motion of the SFD results in the entrapment of air into the oil film, thus producing a bubbly mixture that can not be represented by these models. In this work, an extensive experimental study establishes qualitatively and---for the first time---quantitatively the differences between operation with vapor cavitation and with air entrainment. The experiments show that most operating conditions lead to air entrainment and demonstrate the paramount effect it has on the performance of SFDs, evidencing the limitation of currently available models. Further experiments address the operation of SFDs with controlled bubbly mixtures. These experiments bolster the possibility of modeling air entrapment by representing the lubricant as a homogeneous mixture of air and oil and provide a reliable data base for benchmarking such a model. An analytical model is developed based on a homogeneous mixture assumption and where the bubbles are described by the Rayleigh-Plesset equation. Good agreement is obtained between this model and the measurements performed in the SFD operating with controlled mixtures. A complementary analytical model is devised to estimate the amount of air entrained from the balance of axial flows in the film. A combination of the analytical models for prediction of the air volume fraction and of the hydrodynamic pressures renders promising results for prediction of the performance of SFDs with freely entrained air. The results of this work are of immediate engineering applicability. Furthermore, they represent a firm step to advance the understanding on the effects of air entrapment in the performance of SFD.

Comparison between micellar liquid chromatography and capillary zone electrophoresis for the determination of hydrophobic basic drugs in pharmaceutical preparations.

PubMed

Torres-Cartas, S; Martín-Biosca, Y; Sagrado, S; Villanueva-Camañas, R M; Medina-Hernández, M J

2007-01-01

The determination of highly hydrophobic basic compounds by means of conventional reversed-phase liquid chromatographic methods has several drawbacks. Owing to the characteristics of micellar liquid chromatography (MLC) and capillary electrophoresis (CE), these techniques could be advantageous alternatives to reversed-phase chromatographic methods for the determination of these kinds of compounds. The objective of this study was to develop and compare MLC and CE methods for the determination of antipsychotic basic drugs (amitryptiline, haloperidol, perphenazine and thioridazine) in pharmaceutical preparations. The chromatographic determination of the analytes was performed on a Kromasil C(18) analytical column; the mobile phase was 0.04 m cetyltrimethylammonium bromide (CTAB), at pH 3, containing 5% 1-butanol, at a flow rate of 1 mL/min. The CE separation was performed in a fused-silica capillary with a 50 mm tris-(hydroxymethyl)-aminomethane buffer, pH 7, at an applied voltage of 20 kV, using barbital as internal stardard. The proposed methods are suitable for a reliable quantitation of these compounds in the commercial tablets and drops in terms of accuracy and precision and require a very simple pre-treatment of the samples. By comparing the performance characteristics and experimental details of the MLC and CE methods we conclude that CE seems to be slightly better than MLC in the determination of highly hydrophobic compounds in pharmaceuticals in terms of resolution and economy, taking into account that the limits of detection are not a handicap in pharmaceutical samples. Copyright 2006 John Wiley & Sons, Ltd.

Performance of the G4 Xpert® MTB/RIF assay for the detection of Mycobacterium tuberculosis and rifampin resistance: a retrospective case-control study of analytical and clinical samples from high- and low-tuberculosis prevalence settings.

PubMed

Dharan, Nila J; Blakemore, Robert; Sloutsky, Alex; Kaur, Devinder; Alexander, Richard C; Ghajar, Minoo; Musser, Kimberlee A; Escuyer, Vincent E; Rowlinson, Marie-Claire; Crowe, Susanne; Laniado-Laborin, Rafael; Valli, Eloise; Nabeta, Pamela; Johnson, Pamela; Alland, David

2016-12-20

The Xpert ® MTB/RIF (Xpert) assay is a rapid PCR-based assay for the detection of Mycobacterium tuberculosis complex DNA (MTBc) and mutations associated with rifampin resistance (RIF). An updated version introduced in 2011, the G4 Xpert, included modifications to probe B and updated analytic software. An analytical study was performed to assess Xpert detection of mutations associated with rifampin resistance in rifampin-susceptible and -resistant isolates. A clinical study was performed in which specimens from US and non-US persons suspected of tuberculosis (TB) were tested to determine Xpert performance characteristics. All specimens underwent smear microscopy, mycobacterial culture, conventional drug-susceptibility testing and Xpert testing; DNA from isolates with discordant rifampin resistance results was sequenced. Among 191 laboratory-prepared isolates in the analytical study, Xpert sensitivity for detection of rifampin resistance associated mutations was 97.7% and specificity was 90.8%, which increased to 99.0% after DNA sequencing analysis of the discordant samples. Of the 1,096 subjects in the four clinical studies, 49% were from the US. Overall, Xpert detected MTBc in 439 of 468 culture-positive specimens for a sensitivity of 93.8% (95% confidence interval [CI]: 91.2%-95.7%) and did not detect MTBc in 620 of 628 culture-negative specimens for a specificity of 98.7% (95% CI: 97.5%-99.4%). Sensitivity was 99.7% among smear-positive cases, and 76.1% among smear-negative cases. Non-determinate MTBc detection and false-positive RIF resistance results were low (1.2 and 0.9%, respectively). The updated Xpert assay retained the high sensitivity and specificity of the previous assay versions and demonstrated low rates of non-determinate and RIF resistance false positive results.

Pitting intuitive and analytical thinking against each other: the case of transitivity.

PubMed

Rusou, Zohar; Zakay, Dan; Usher, Marius

2013-06-01

Identifying which thinking mode, intuitive or analytical, yields better decisions has been a major subject of inquiry by decision-making researchers. Yet studies show contradictory results. One possibility is that the ambiguity is due to the variability in experimental conditions across studies. Our hypothesis is that decision quality depends critically on the level of compatibility between the thinking mode employed in the decision and the nature of the decision-making task. In two experiments, we pitted intuition and analytical thinking against each other on tasks that were either mainly intuitive or mainly analytical. Thinking modes, as well as task characteristics, were manipulated in a factorial design, with choice transitivity as the dependent measure. Results showed higher choice consistency (transitivity) when thinking mode and the characteristics of the decision task were compatible.

Flexible aircraft dynamic modeling for dynamic analysis and control synthesis

NASA Technical Reports Server (NTRS)

Schmidt, David K.

1989-01-01

The linearization and simplification of a nonlinear, literal model for flexible aircraft is highlighted. Areas of model fidelity that are critical if the model is to be used for control system synthesis are developed and several simplification techniques that can deliver the necessary model fidelity are discussed. These techniques include both numerical and analytical approaches. An analytical approach, based on first-order sensitivity theory is shown to lead not only to excellent numerical results, but also to closed-form analytical expressions for key system dynamic properties such as the pole/zero factors of the vehicle transfer-function matrix. The analytical results are expressed in terms of vehicle mass properties, vibrational characteristics, and rigid-body and aeroelastic stability derivatives, thus leading to the underlying causes for critical dynamic characteristics.

Experimental and analytical determination of characteristics affecting light aircraft landing-gear dynamics

NASA Technical Reports Server (NTRS)

Fasanella, E. L.; Mcgehee, J. R.; Pappas, M. S.

1977-01-01

An experimental and analytical investigation was conducted to determine which characteristics of a light aircraft landing gear influence gear dynamic behavior significantly. The investigation focused particularly on possible modification for load control. Pseudostatic tests were conducted to determine the gear fore-and-aft spring constant, axial friction as a function of drag load, brake pressure-torque characteristics, and tire force-deflection characteristics. To study dynamic tire response, vertical drops were conducted at impact velocities of 1.2, 1.5, and 1.8 m/s onto a level surface; to determine axial-friction effects, a second series of vertical drops were made at 1.5 m/s onto surfaces inclined 5 deg and 10 deg to the horizontal. An average dynamic axial-friction coefficient of 0.15 was obtained by comparing analytical data with inclined surface drop test data. Dynamic strut bending and associated axial friction were found to be severe for the drop tests on the 10 deg surface.

Downward continuation of airborne gravity data by means of the change of boundary approach

NASA Astrophysics Data System (ADS)

Mansi, A. H.; Capponi, M.; Sampietro, D.

2018-03-01

Within the modelling of gravity data, a common practice is the upward/downward continuation of the signal, i.e. the process of continuing the gravitational signal in the vertical direction away or closer to the sources, respectively. The gravity field, being a potential field, satisfies the Laplace's equation outside the masses and this means that it allows to unambiguously perform this analytical continuation only in a source-free domain. The analytical continuation problem has been solved both in the space and spectral domains by exploiting different algorithms. As well known, the downward continuation operator, differently from the upward one, is an unstable operator, due to its spectral characteristics similar to those of a high-pass filter, and several regularization methods have been proposed in order to stabilize it. In this work, an iterative procedure to downward/upward continue the gravity field observations, acquired at different altitudes, is proposed. This methodology is based on the change of boundary principle and it has been expressively thought for aerogravimetric observations for geophysical exploration purposes. Within this field of application, usually several simplifications can be applied, basically due to the specific characteristics of the airborne surveys which are usually flown at almost constant altitude as close as possible to the terrain. For instance, these characteristics, as shown in the present work, allow to perform the downward continuation without the need of any regularization. The goodness of the proposed methodology has been evaluated by means of a numerical test on real data, acquired in the South of Australia. The test shows that it is possible to move the aerogravimetric data, acquired along tracks with a maximum height difference of about 250 m, with accuracies of the order of 10^{-3} mGal.

Analytical characterization of products obtained from slow pyrolysis of Calophyllum inophyllum seed cake: study on performance and emission characteristics of direct injection diesel engine fuelled with bio-oil blends.

PubMed

Rajamohan, Sakthivel; Kasimani, Ramesh

2018-04-01

This paper aims to analyse the characteristics and properties of the fractions obtained from slow pyrolysis of non-edible seed cake of Calophyllum inophyllum (CI). The gas, bio-oil and biochar obtained from the pyrolysis carried out at 500 °C in a fixed bed batch type reactor at a heating rate of 30 °C/min were characterized by various analytical techniques. Owing to the high volatile content of CI biomass (72.61%), it was selected as the raw material in this present investigation. GC-MS and FT-IR analysis of bio-oil showed the presence of higher amount of oxygenated compounds, phenol derivatives, esters, acid and furans. The physicochemical properties of the bio-oil were tested as per ASTM norms which imply that bio-oil is a highly viscous liquid with lower heating value as compared to that of diesel fuel. The chemical composition of evolved gas was analysed by using GC testing which revealed the presence of combustible components. The FT-IR characterization of biochar showed the presence of aliphatic and aromatic hydrocarbons whereas the elevated amount of carbon in biochar indicates its potential to be used as solid fuel. The performance and emission characteristics of CI engine were assessed with different CI bio-oil blends and compared with baseline diesel fuel. The results showed that addition of bio-oil leads to decreased brake thermal efficiency and increased brake specific energy consumption. Meanwhile, increase in blend ratio reduces harmful pollutants such as oxides of nitrogen and smoke in the exhaust. From the engine testing, it is suggested to employ 20% of CI bio-oil blends in CI engine to obtain better operation.

Comparative study of I- V methods to extract Au/FePc/p-Si Schottky barrier diode parameters

NASA Astrophysics Data System (ADS)

Oruç, Çiğdem; Altındal, Ahmet

2018-01-01

So far, various methods have been proposed to extract the Schottky diode parameters from measured current-voltage characteristics. In this work, Schottky barrier diode with structure of Au/2(3),9(10),16(17),23(24)-tetra(4-(4-methoxyphenyl)-8-methylcoumarin-7 oxy) phthalocyaninatoiron(II) (FePc)/p-Si was fabricated and current-voltage measurements were carried out on it. In addition, current-voltage measurements were also performed on Au/p-Si structure, without FePc, to clarify the influence of the presence of an interface layer on the device performance. The measured current-voltage characteristics indicate that the interface properties of a Schottky barrier diode can be controlled by the presence of an organic interface layer. It is found that the room temperature barrier height of Au/FePc/p-Si structure is larger than that of the Au/p-Si structure. The obtained forward bias current-voltage characteristics of the Au/FePc/p-Si device was analysed by five different analytical methods. It is found that the extracted values of SBD parameters strongly depends on the method used.

Optical Characteristics of Vertical Cavity Surface Emitting Lasers and Two Dimensional Coherently Coupled Arrays.

NASA Astrophysics Data System (ADS)

Catchmark, Jeffrey Michael

1995-01-01

The following describes extensive experimental and theoretical research concerning the optical, electrical and thermal characteristics of GaAs/AlGaAs vertical cavity surface emitting lasers (VCSELs) and coherently coupled two dimensional VCSEL arrays grown by molecular beam epitaxy. The temperature and wavelength performance of VCSELs containing various epitaxial designs is discussed in detail. By employing a high barrier confinement spacer region and by blue shifting the optical gain with respect to the Fabry Perot transmission wavelength, greater than 150^circ rm C continuous wave operation was obtained. This is accomplished while maintaining a variation in the threshold current of only +/-0.93mA over a temperature range of 150^circrm C. This exceptional performance is achieved while attaining a minimum threshold current of approximately 4.3mA at 75^circrm C. In addition, the optical characteristics of multi-transverse mode VCSEL arrays are examined experimentally. A total of nine transverse modes have been identified and are found to couple coherently into distinct array modes. While operating in higher order transverse modes, a record 1.4W (pulsed) of optical power is obtained from a 15 x 15 VCSEL array. Array mode formation in coherently coupled VCSEL arrays is also examined theoretically. A numerical model is developed to describe the formation of supermodes in reflectivity modulated VCSEL arrays. Using this model, the effects of depth of reflectivity modulation, cavity length, window size and grid size on mode formation are explored. The array modes predicted by this model are in agreement with those observed experimentally. Analytic models will also be presented describing the effects of thermally induced waveguiding on the optical characteristics of VCSELs operating in the fundamental transverse mode. A thermal waveguide is found to have a significant effect on the spot size and radius of curvature of the phase of the fundamental optical mode. In addition, an analytic model is developed to predict the higher order transverse modes of a VCSEL exhibiting a cruciform type geometry.

Orbiter Landing Loads Math Model Description and Correlation with ALT Flight Data

NASA Technical Reports Server (NTRS)

Hamilton, D. A.; Schliesing, J. A.; Zupp, G. A., Jr.

1980-01-01

Results of the space shuttle approach and landing test are examined in order to assess landing gear characteristics and performance and verify landing dynamic analyses. The landing gears were instrumented with load-calibrated strain gages, a wheel-speed sensor, and strut stroke measurement devices. The mathematical procedure used in predicting the shuttle touchdown loads and dynamics is presented together with the comparisons between measured flight data and the analytical predictions. Conclusions from these data are also presented.

Wind tunnel investigation of a 14 foot vertical axis windmill

NASA Technical Reports Server (NTRS)

Muraca, R. J.; Guillotte, R. J.

1976-01-01

A full scale wind tunnel investigation was made to determine the performance characteristics of a 14 ft diameter vertical axis windmill. The parameters measured were wind velocity, shaft torque, shaft rotation rate, along with the drag and yawing moment. A velocity survey of the flow field downstream of the windmill was also made. The results of these tests along with some analytically predicted data are presented in the form of generalized data as a function of tip speed ratio.

Current and future technology in radial and axial gas turbines

NASA Technical Reports Server (NTRS)

Rohlik, H. E.

1983-01-01

Design approaches and flow analysis techniques currently employed by aircraft engine manufacturers are assessed. Studies were performed to define the characteristics of aircraft and engines for civil missions of the 1990's and beyond. These studies, coupled with experience in recent years, identified the critical technologies needed to meet long range goals in fuel economy and other operating costs. Study results, recent and current research and development programs, and an estimate of future design and analytic capabilities are discussed.

The evolving potential of companion diagnostics.

PubMed

Khoury, Joseph D

2016-01-01

The scope of companion diagnostics in cancer has undergone significant shifts in the past few years, with increased development of targeted therapies and novel testing platforms. This has provided new opportunities to effect unprecedented paradigm shifts in the application of personalized medicine principles for patients with cancer. These shifts involve assay platforms, analytes, regulations, and therapeutic approaches. As opportunities involving each of these facets of companion diagnostics expand, close collaborations between key stakeholders should be enhanced to ensure optimal performance characteristics and patient outcomes.

In Vivo Anomalous Diffusion and Weak Ergodicity Breaking of Lipid Granules

NASA Astrophysics Data System (ADS)

Jeon, Jae-Hyung; Tejedor, Vincent; Burov, Stas; Barkai, Eli; Selhuber-Unkel, Christine; Berg-Sørensen, Kirstine; Oddershede, Lene; Metzler, Ralf

2011-01-01

Combining extensive single particle tracking microscopy data of endogenous lipid granules in living fission yeast cells with analytical results we show evidence for anomalous diffusion and weak ergodicity breaking. Namely we demonstrate that at short times the granules perform subdiffusion according to the laws of continuous time random walk theory. The associated violation of ergodicity leads to a characteristic turnover between two scaling regimes of the time averaged mean squared displacement. At longer times the granule motion is consistent with fractional Brownian motion.

A critical review of inductively coupled plasma-mass spectrometry for geoanalysis, geochemistry and hydrology, Part 1. Analytical performance

USGS Publications Warehouse

Brenner, I.B.; Taylor, Howard E.

1992-01-01

Present-day inductively coupled plasma-mass spectrometry (ICP-MS) instrumentation is described briefly. Emphasis is placed on performance characteristics for geoanalysis, geochemistry, and hydrology. Applications where ICP-MS would be indispensable are indicated. Determination of geochemically diagnostic trace elements (such as the rare earth elements [REE], U and Th), of isotope ratios for fingerprinting, tracer and other geo-isotope applications, and benchmark isotope dilution determinations are considered to be typical priority applications for ICP-MS. It is concluded that ICP-MS furnishes unique geoanalytical and environmental data that are not readily provided by conventional spectroscopic (emission and absorption) techniques.

The kinematic Stirling engine as an energy conversion subsystem for paraboloidal dish solar thermal plants

NASA Technical Reports Server (NTRS)

Bowyer, J. M.

1984-01-01

The potential of a suitably designed and economically manufactured Stirling engine as the energy conversion subsystem of a paraboloidal dish-Stirling solar thermal power module was estimated. Results obtained by elementary cycle analyses were shown to match quite well the performance characteristics of an advanced kinematic Stirling engine, the United Stirling P-40, as established by current prototypes of the engine and by a more sophisticated analytic model of its advanced derivative. In addition to performance, brief consideration was given to other Stirling engine criteria such as durability, reliability, and serviceability. Production costs were not considered here.

A Generalized Pivotal Quantity Approach to Analytical Method Validation Based on Total Error.

PubMed

Yang, Harry; Zhang, Jianchun

2015-01-01

The primary purpose of method validation is to demonstrate that the method is fit for its intended use. Traditionally, an analytical method is deemed valid if its performance characteristics such as accuracy and precision are shown to meet prespecified acceptance criteria. However, these acceptance criteria are not directly related to the method's intended purpose, which is usually a gurantee that a high percentage of the test results of future samples will be close to their true values. Alternate "fit for purpose" acceptance criteria based on the concept of total error have been increasingly used. Such criteria allow for assessing method validity, taking into account the relationship between accuracy and precision. Although several statistical test methods have been proposed in literature to test the "fit for purpose" hypothesis, the majority of the methods are not designed to protect the risk of accepting unsuitable methods, thus having the potential to cause uncontrolled consumer's risk. In this paper, we propose a test method based on generalized pivotal quantity inference. Through simulation studies, the performance of the method is compared to five existing approaches. The results show that both the new method and the method based on β-content tolerance interval with a confidence level of 90%, hereafter referred to as the β-content (0.9) method, control Type I error and thus consumer's risk, while the other existing methods do not. It is further demonstrated that the generalized pivotal quantity method is less conservative than the β-content (0.9) method when the analytical methods are biased, whereas it is more conservative when the analytical methods are unbiased. Therefore, selection of either the generalized pivotal quantity or β-content (0.9) method for an analytical method validation depends on the accuracy of the analytical method. It is also shown that the generalized pivotal quantity method has better asymptotic properties than all of the current methods. Analytical methods are often used to ensure safety, efficacy, and quality of medicinal products. According to government regulations and regulatory guidelines, these methods need to be validated through well-designed studies to minimize the risk of accepting unsuitable methods. This article describes a novel statistical test for analytical method validation, which provides better protection for the risk of accepting unsuitable analytical methods. © PDA, Inc. 2015.

Decay characteristics of electroadhesive forces by periodic electrodes in dielectric layers

NASA Astrophysics Data System (ADS)

Lee, Junseok; Cha, Youngsu

2017-07-01

Electroadhesive force is the force generated by induced dipoles in the gradient of an electric field. Owing to its benefits of mechanical characteristics and versatility, it is widely used to hold and manipulate objects in robotic applications. So far, most studies in this field have been focused on the maximization of the magnitude of electroadhesive force. In this paper, we focus on the decay characteristics of electroadhesive force depending on the spatial distance from electrodes to employ the force to precisely separate a single layer from stacked dielectric layers. It turns out that all configurations with periodically repeating electrodes' arrangement, have the same decay characteristics which significantly depend on the geometrical period of the electrode patterns. Also, we find that the other parameters including the applied voltage and geometry of electrodes have little effect on the decay characteristics. The electric potential of an arbitrary electrode configuration is expanded in terms of the Fourier series, and we use it to analytically prove the high dependence of decay characteristics on the geometrical period. Numerical analysis is performed using the finite element method.

An analytics of electricity consumption characteristics based on principal component analysis

NASA Astrophysics Data System (ADS)

Feng, Junshu

2018-02-01

Abstract . More detailed analysis of the electricity consumption characteristics can make demand side management (DSM) much more targeted. In this paper, an analytics of electricity consumption characteristics based on principal component analysis (PCA) is given, which the PCA method can be used in to extract the main typical characteristics of electricity consumers. Then, electricity consumption characteristics matrix is designed, which can make a comparison of different typical electricity consumption characteristics between different types of consumers, such as industrial consumers, commercial consumers and residents. In our case study, the electricity consumption has been mainly divided into four characteristics: extreme peak using, peak using, peak-shifting using and others. Moreover, it has been found that industrial consumers shift their peak load often, meanwhile commercial and residential consumers have more peak-time consumption. The conclusions can provide decision support of DSM for the government and power providers.

Estimated Benefits of Variable-Geometry Wing Camber Control for Transport Aircraft

NASA Technical Reports Server (NTRS)

Bolonkin, Alexander; Gilyard, Glenn B.

1999-01-01

Analytical benefits of variable-camber capability on subsonic transport aircraft are explored. Using aerodynamic performance models, including drag as a function of deflection angle for control surfaces of interest, optimal performance benefits of variable camber are calculated. Results demonstrate that if all wing trailing-edge surfaces are available for optimization, drag can be significantly reduced at most points within the flight envelope. The optimization approach developed and illustrated for flight uses variable camber for optimization of aerodynamic efficiency (maximizing the lift-to-drag ratio). Most transport aircraft have significant latent capability in this area. Wing camber control that can affect performance optimization for transport aircraft includes symmetric use of ailerons and flaps. In this paper, drag characteristics for aileron and flap deflections are computed based on analytical and wind-tunnel data. All calculations based on predictions for the subject aircraft and the optimal surface deflection are obtained by simple interpolation for given conditions. An algorithm is also presented for computation of optimal surface deflection for given conditions. Benefits of variable camber for a transport configuration using a simple trailing-edge control surface system can approach more than 10 percent, especially for nonstandard flight conditions. In the cruise regime, the benefit is 1-3 percent.

Wind flow characteristics in the wakes of large wind turbines. Volume 1: Analytical model development

NASA Technical Reports Server (NTRS)

Eberle, W. R.

1981-01-01

A computer program to calculate the wake downwind of a wind turbine was developed. Turbine wake characteristics are useful for determining optimum arrays for wind turbine farms. The analytical model is based on the characteristics of a turbulent coflowing jet with modification for the effects of atmospheric turbulence. The program calculates overall wake characteristics, wind profiles, and power recovery for a wind turbine directly in the wake of another turbine, as functions of distance downwind of the turbine. The calculation procedure is described in detail, and sample results are presented to illustrate the general behavior of the wake and the effects of principal input parameters.

Analytic and experimental evaluation of flowing air test conditions for selected metallics in a shuttle TPS application

NASA Technical Reports Server (NTRS)

Schaefer, J. W.; Tong, H.; Clark, K. J.; Suchsland, K. E.; Neuner, G. J.

1975-01-01

A detailed experimental and analytical evaluation was performed to define the response of TD nickel chromium alloy (20 percent chromium) and coated columbium (R512E on CB-752 and VH-109 on WC129Y) to shuttle orbiter reentry heating. Flight conditions important to the response of these thermal protection system (TPS) materials were calculated, and test conditions appropriate to simulation of these flight conditions in flowing air ground test facilities were defined. The response characteristics of these metallics were then evaluated for the flight and representative ground test conditions by analytical techniques employing appropriate thermochemical and thermal response computer codes and by experimental techniques employing an arc heater flowing air test facility and flat face stagnation point and wedge test models. These results were analyzed to define the ground test requirements to obtain valid TPS response characteristics for application to flight. For both material types in the range of conditions appropriate to the shuttle application, the surface thermochemical response resulted in a small rate of change of mass and a negligible energy contribution. The thermal response in terms of surface temperature was controlled by the net heat flux to the surface; this net flux was influenced significantly by the surface catalycity and surface emissivity. The surface catalycity must be accounted for in defining simulation test conditions so that proper heat flux levels to, and therefore surface temperatures of, the test samples are achieved.

Newcomer adjustment during organizational socialization: a meta-analytic review of antecedents, outcomes, and methods.

PubMed

Bauer, Talya N; Bodner, Todd; Erdogan, Berrin; Truxillo, Donald M; Tucker, Jennifer S

2007-05-01

The authors tested a model of antecedents and outcomes of newcomer adjustment using 70 unique samples of newcomers with meta-analytic and path modeling techniques. Specifically, they proposed and tested a model in which adjustment (role clarity, self-efficacy, and social acceptance) mediated the effects of organizational socialization tactics and information seeking on socialization outcomes (job satisfaction, organizational commitment, job performance, intentions to remain, and turnover). The results generally supported this model. In addition, the authors examined the moderating effects of methodology on these relationships by coding for 3 methodological issues: data collection type (longitudinal vs. cross-sectional), sample characteristics (school-to-work vs. work-to-work transitions), and measurement of the antecedents (facet vs. composite measurement). Discussion focuses on the implications of the findings and suggestions for future research. 2007 APA, all rights reserved

The Abbott Architect c8000: analytical performance and productivity characteristics of a new analyzer applied to general chemistry testing.

PubMed

Pauli, Daniela; Seyfarth, Michael; Dibbelt, Leif

2005-01-01

Applying basic potentiometric and photometric assays, we evaluated the fully automated random access chemistry analyzer Architect c8000, a new member of the Abbott Architect system family, with respect to both its analytical and operational performance and compared it to an established high-throughput chemistry platform, the Abbott Aeroset. Our results demonstrate that intra- and inter-assay imprecision, inaccuracy, lower limit of detection and linear range of the c8000 generally meet actual requirements of laboratory diagnosis; there were only rare exceptions, e.g. assays for plasma lipase or urine uric acid which apparently need to be improved by additional rinsing of reagent pipettors. Even with plasma exhibiting CK activities as high as 40.000 U/l, sample carryover by the c8000 could not be detected. Comparison of methods run on the c8000 and the Aeroset revealed correlation coefficients of 0.98-1.00; if identical chemistries were applied on both analyzers, slopes of regression lines approached unity. With typical laboratory workloads including 10-20% STAT samples and up to 10% samples with high analyte concentrations demanding dilutional reruns, steady-state throughput numbers of 700 to 800 tests per hour were obtained with the c8000. The system generally responded to STAT orders within 2 minutes yielding analytical STAT order completion times of 5 to 15 minutes depending on the type and number of assays requested per sample. Due to its extended test and sample processing capabilities and highly comfortable software, the c8000 may meet the varying needs of clinical laboratories rather well.

Validation of an SPME method, using PDMS, PA, PDMS-DVB, and CW-DVB SPME fiber coatings, for analysis of organophosphorus insecticides in natural waters.

PubMed

Lambropoulou, D A; Sakkas, V A; Albanis, T A

2002-11-01

Solid-phase microextraction (SPME) has been optimized and applied to the determination of the organophosphorus insecticides diazinon, dichlofenthion, parathion methyl, malathion, fenitrothion, fenthion, parathion ethyl, bromophos methyl, bromophos ethyl, and ethion in natural waters. Four types of SPME fiber coated with different stationary phases (PDMS, PA, PDMS-DVB, and CW-DVB) were used to examine their extraction efficiencies for the compounds tested. Conditions that might affect the SPME procedure, such as extraction time and salt content, were investigated to determine the analytical performance of these fiber coatings for organophosphorus insecticides. The optimized procedure was applied to natural waters - tap, sea, river, and lake water - spiked in the concentration range 0.5 to 50 micro g L(-1) to obtain the analytical characteristics. Recoveries were relatively high - >80% for all types of aqueous sample matrix - and the calibration plots were reproducible and linear (R(2)>0.982) for all analytes with all the fibers tested. The limits of detection ranged from 2 to 90 ng L(-1), depending on the detector and the compound investigated, with relative standard deviations in the range 3-15% at all the concentration levels tested. The SPME partition coefficients (K(f)) of the organophosphorus insecticides were calculated experimentally for all the polymer coatings. The effect of organic matter such as humic acids on extraction efficiency was also studied. The analytical performance of the SPME procedure using all the fibers in the tested natural waters proved effective for the compounds.

Performance of mixed RF/FSO systems in exponentiated Weibull distributed channels

NASA Astrophysics Data System (ADS)

Zhao, Jing; Zhao, Shang-Hong; Zhao, Wei-Hu; Liu, Yun; Li, Xuan

2017-12-01

This paper presented the performances of asymmetric mixed radio frequency (RF)/free-space optical (FSO) system with the amplify-and-forward relaying scheme. The RF channel undergoes Nakagami- m channel, and the Exponentiated Weibull distribution is adopted for the FSO component. The mathematical formulas for cumulative distribution function (CDF), probability density function (PDF) and moment generating function (MGF) of equivalent signal-to-noise ratio (SNR) are achieved. According to the end-to-end statistical characteristics, the new analytical expressions of outage probability are obtained. Under various modulation techniques, we derive the average bit-error-rate (BER) based on the Meijer's G function. The evaluation and simulation are provided for the system performance, and the aperture average effect is discussed as well.

Engineering evaluation of SSME dynamic data from engine tests and SSV flights

NASA Technical Reports Server (NTRS)

1986-01-01

An engineering evaluation of dynamic data from SSME hot firing tests and SSV flights is summarized. The basic objective of the study is to provide analyses of vibration, strain and dynamic pressure measurements in support of MSFC performance and reliability improvement programs. A brief description of the SSME test program is given and a typical test evaluation cycle reviewed. Data banks generated to characterize SSME component dynamic characteristics are described and statistical analyses performed on these data base measurements are discussed. Analytical models applied to define the dynamic behavior of SSME components (such as turbopump bearing elements and the flight accelerometer safety cut-off system) are also summarized. Appendices are included to illustrate some typical tasks performed under this study.

Generalized simulation technique for turbojet engine system analysis

NASA Technical Reports Server (NTRS)

Seldner, K.; Mihaloew, J. R.; Blaha, R. J.

1972-01-01

A nonlinear analog simulation of a turbojet engine was developed. The purpose of the study was to establish simulation techniques applicable to propulsion system dynamics and controls research. A schematic model was derived from a physical description of a J85-13 turbojet engine. Basic conservation equations were applied to each component along with their individual performance characteristics to derive a mathematical representation. The simulation was mechanized on an analog computer. The simulation was verified in both steady-state and dynamic modes by comparing analytical results with experimental data obtained from tests performed at the Lewis Research Center with a J85-13 engine. In addition, comparison was also made with performance data obtained from the engine manufacturer. The comparisons established the validity of the simulation technique.

Performance and Operational Characteristics for a Dual Brayton Space Power System With Common Gas Inventory

NASA Technical Reports Server (NTRS)

Johnson, Paul K.; Mason, Lee S.

2006-01-01

This paper provides an analytical evaluation on the operation and performance of a dual Brayton common gas system. The NASA Glenn Research Center in-house computer program Closed Cycle System Simulation (CCSS) was used to construct a model of two identical 50 kWe-class recuperated closed-Brayton-cycle (CBC) power conversion units that share a common gas inventory and single heat source. As operating conditions for each CBC change, the total gas inventory is redistributed between the two units and overall system performance is affected. Several steady-state off-design operating points were analyzed by varying turbine inlet temperature and turbo-alternator shaft rotational speed to investigate the interaction of the two units.

High-temperature ratchets with sawtooth potentials

NASA Astrophysics Data System (ADS)

Rozenbaum, Viktor M.; Shapochkina, Irina V.; Sheu, Sheh-Yi; Yang, Dah-Yen; Lin, Sheng Hsien

2016-11-01

The concept of the effective potential is suggested as an efficient instrument to get a uniform analytical description of stochastic high-temperature on-off flashing and rocking ratchets. The analytical representation for the average particle velocity, obtained within this technique, allows description of ratchets with sharp potentials (and potentials with jumps in particular). For sawtooth potentials, the explicit analytical expressions for the average velocity of on-off flashing and rocking ratchets valid for arbitrary frequencies of potential energy fluctuations are derived; the difference in their high-frequency asymptotics is explored for the smooth and cusped profiles, and profiles with jumps. The origin of the difference as well as the appearance of the jump behavior in ratchet characteristics are interpreted in terms of self-similar universal solutions which give the continuous description of the effect. It is shown how the jump behavior in motor characteristics arises from the competition between the characteristic times of the system.

Holistic rubric vs. analytic rubric for measuring clinical performance levels in medical students.

PubMed

Yune, So Jung; Lee, Sang Yeoup; Im, Sun Ju; Kam, Bee Sung; Baek, Sun Yong

2018-06-05

Task-specific checklists, holistic rubrics, and analytic rubrics are often used for performance assessments. We examined what factors evaluators consider important in holistic scoring of clinical performance assessment, and compared the usefulness of applying holistic and analytic rubrics respectively, and analytic rubrics in addition to task-specific checklists based on traditional standards. We compared the usefulness of a holistic rubric versus an analytic rubric in effectively measuring the clinical skill performances of 126 third-year medical students who participated in a clinical performance assessment conducted by Pusan National University School of Medicine. We conducted a questionnaire survey of 37 evaluators who used all three evaluation methods-holistic rubric, analytic rubric, and task-specific checklist-for each student. The relationship between the scores on the three evaluation methods was analyzed using Pearson's correlation. Inter-rater agreement was analyzed by Kappa index. The effect of holistic and analytic rubric scores on the task-specific checklist score was analyzed using multiple regression analysis. Evaluators perceived accuracy and proficiency to be major factors in objective structured clinical examinations evaluation, and history taking and physical examination to be major factors in clinical performance examinations evaluation. Holistic rubric scores were highly related to the scores of the task-specific checklist and analytic rubric. Relatively low agreement was found in clinical performance examinations compared to objective structured clinical examinations. Meanwhile, the holistic and analytic rubric scores explained 59.1% of the task-specific checklist score in objective structured clinical examinations and 51.6% in clinical performance examinations. The results show the usefulness of holistic and analytic rubrics in clinical performance assessment, which can be used in conjunction with task-specific checklists for more efficient evaluation.

Helminth ova control in sludge: a review.

PubMed

Jiménez, B

2007-01-01

Sludge reuse for agricultural production or soil reclamation is a common practice in several countries, but it entails risks if not properly performed. One such risk is the dissemination of helminthiases diseases. As a consequence, international criteria and national standards set values to limit their content in biosolids. However, little information is available on how to inactivate helminth ova from sludge, particularly when a high content is involved as is the case in the developing world. Moreover, treatment criteria are based on a limited number of studies dealing with local characteristics that, when applied to the conditions in developing countries, produce poor results. This is because design criteria were developed for Ascaris (a kind of helminth) while sludge contains a variety of genera. In addition, much information on helminth ova was produced a long time ago using inaccurate analytical techniques. This paper summarizes research and recent technical information from the literature concerning: (a) the general characteristics of helminth ova; (b) the common helminth ova genera found in sludge; (c) the main removal and inactivation mechanisms, (d) the processes that have proven effective in practical conditions at inactivating helminth ova; and (e) analytical techniques used to enumerate these pathogens.

Analytic model of a multi-electron atom

NASA Astrophysics Data System (ADS)

Skoromnik, O. D.; Feranchuk, I. D.; Leonau, A. U.; Keitel, C. H.

2017-12-01

A fully analytical approximation for the observable characteristics of many-electron atoms is developed via a complete and orthonormal hydrogen-like basis with a single-effective charge parameter for all electrons of a given atom. The basis completeness allows us to employ the secondary-quantized representation for the construction of regular perturbation theory, which includes in a natural way correlation effects, converges fast and enables an effective calculation of the subsequent corrections. The hydrogen-like basis set provides a possibility to perform all summations over intermediate states in closed form, including both the discrete and continuous spectra. This is achieved with the help of the decomposition of the multi-particle Green function in a convolution of single-electronic Coulomb Green functions. We demonstrate that our fully analytical zeroth-order approximation describes the whole spectrum of the system, provides accuracy, which is independent of the number of electrons and is important for applications where the Thomas-Fermi model is still utilized. In addition already in second-order perturbation theory our results become comparable with those via a multi-configuration Hartree-Fock approach.

Semi-analytical discontinuous Galerkin finite element method for the calculation of dispersion properties of guided waves in plates.

PubMed

Hebaz, Salah-Eddine; Benmeddour, Farouk; Moulin, Emmanuel; Assaad, Jamal

2018-01-01

The development of reliable guided waves inspection systems is conditioned by an accurate knowledge of their dispersive properties. The semi-analytical finite element method has been proven to be very practical for modeling wave propagation in arbitrary cross-section waveguides. However, when it comes to computations on complex geometries to a given accuracy, it still has a major drawback: the high consumption of resources. Recently, discontinuous Galerkin finite element method (DG-FEM) has been found advantageous over the standard finite element method when applied as well in the frequency domain. In this work, a high-order method for the computation of Lamb mode characteristics in plates is proposed. The problem is discretised using a class of DG-FEM, namely, the interior penalty methods family. The analytical validation is performed through the homogeneous isotropic case with traction-free boundary conditions. Afterwards, functionally graded material plates are analysed and a numerical example is presented. It was found that the obtained results are in good agreement with those found in the literature.

Protein Adsorption onto Nanomaterials for the Development of Biosensors and Analytical Devices: A Review

PubMed Central

Bhakta, Samir A.; Evans, Elizabeth; Benavidez, Tomás E.; Garcia, Carlos D.

2014-01-01

An important consideration for the development of biosensors is the adsorption of the bio recognition element to the surface of a substrate. As the first step in the immobilization process, adsorption affects most immobilization routes and much attention is given into the research of this process to maximize the overall activity of the bio sensor. The use of nanomaterials, specifically nanoparticles and nanostructured films, offers advantageous properties that can be fine-tuned for interaction with specific proteins to maximize activity, minimize structural changes, and enhance the catalytic step. In the biosensor field, protein-nanomaterial interactions are an emerging trend that span across many disciplines. This review addresses recent publications about the proteins most frequently used, their most relevant characteristics, and the conditions required to adsorb them to nanomaterials. When relevant and available, subsequent analytical figures of merits are discussed for selected biosensors. The general trend amongst the research papers allows concluding that the use of nanomaterials has already provided significant improvements in the analytical performance of many biosensors and that this research field will continue to grow. PMID:25892065

Characterization of the gas sensors based on polymer-coated resonant microcantilevers for the detection of volatile organic compounds.

PubMed

Dong, Ying; Gao, Wei; Zhou, Qin; Zheng, Yi; You, Zheng

2010-06-25

The gas sensors based on polymer-coated resonant microcantilevers for volatile organic compounds (VOCs) detection are investigated. A method to characterize the gas sensors through sensor calibration is proposed. The expressions for the estimation of the characteristic parameters are derived. The effect of the polymer coating location on the sensor's sensitivity is investigated and the formula to calculate the polymer-analyte partition coefficient without knowing the polymer coating features is presented for the first time. Three polymers: polyethyleneoxide (PEO), polyethylenevinylacetate (PEVA) and polyvinylalcohol (PVA) are used to perform the experiments. Six organic solvents: toluene, benzene, ethanol, acetone, hexane and octane are used as analytes. The response time, reversibility, hydrophilicity, sensitivity and selectivity of the polymer layers are discussed. According to the results, highly sensitive sensors for each of the analytes are proposed. Based on the characterization method, a convenient and flexible way to the construction of electric nose system by the polymer-coated resonant microcantilevers can be achieved. Copyright 2010 Elsevier B.V. All rights reserved.

Development of design and analysis methodology for composite bolted joints

NASA Astrophysics Data System (ADS)

Grant, Peter; Sawicki, Adam

1991-05-01

This paper summarizes work performed to develop composite joint design methodology for use on rotorcraft primary structure, determine joint characteristics which affect joint bearing and bypass strength, and develop analytical methods for predicting the effects of such characteristics in structural joints. Experimental results have shown that bearing-bypass interaction allowables cannot be defined using a single continuous function due to variance of failure modes for different bearing-bypass ratios. Hole wear effects can be significant at moderate stress levels and should be considered in the development of bearing allowables. A computer program has been developed and has successfully predicted bearing-bypass interaction effects for the (0/+/-45/90) family of laminates using filled hole and unnotched test data.

Solar thermal plant impact analysis and requirements definition

NASA Technical Reports Server (NTRS)

Gupta, Y. P.

1980-01-01

Progress on a continuing study comprising of ten tasks directed at defining impact and requirements for solar thermal power systems (SPS), 1 to 10 MWe each in capacity, installed during 1985 through year 2000 in a utility or a nonutility load in the United States is summarized. The point focus distributed receiver (PFDR) solar power systems are emphasized. Tasks 1 through 4, completed to date, include the development of a comprehensive data base on SPS configurations, their performance, cost, availability, and potential applications; user loads, regional characteristics, and an analytic methodology that incorporates the generally accepted utility financial planning methods and several unique modifications to treat the significant and specific characteristics of solar power systems deployed in either central or distributed power generation modes, are discussed.

U.S. Geological Survey Standard Reference Sample Project: Performance Evaluation of Analytical Laboratories

USGS Publications Warehouse

Long, H. Keith; Daddow, Richard L.; Farrar, Jerry W.

1998-01-01

Since 1962, the U.S. Geological Survey (USGS) has operated the Standard Reference Sample Project to evaluate the performance of USGS, cooperator, and contractor analytical laboratories that analyze chemical constituents of environmental samples. The laboratories are evaluated by using performance evaluation samples, called Standard Reference Samples (SRSs). SRSs are submitted to laboratories semi-annually for round-robin laboratory performance comparison purposes. Currently, approximately 100 laboratories are evaluated for their analytical performance on six SRSs for inorganic and nutrient constituents. As part of the SRS Project, a surplus of homogeneous, stable SRSs is maintained for purchase by USGS offices and participating laboratories for use in continuing quality-assurance and quality-control activities. Statistical evaluation of the laboratories results provides information to compare the analytical performance of the laboratories and to determine possible analytical deficiences and problems. SRS results also provide information on the bias and variability of different analytical methods used in the SRS analyses.

Narcissism and Self-Insight: A Review and Meta-Analysis of Narcissists' Self-Enhancement Tendencies.

PubMed

Grijalva, Emily; Zhang, Luyao

2016-01-01

The current article reviews the narcissism-self-enhancement literature using a multilevel meta-analytic technique. Specifically, we focus on self-insight self-enhancement (i.e., whether narcissists perceive themselves more positively than they are perceived by others); thus, we only include studies that compare narcissists' self-reports to observer reports or objective measures. Results from 171 correlations reported in 36 empirical studies (N = 6,423) revealed that the narcissism-self-enhancement relationship corrected for unreliability in narcissism was .21 (95% confidence interval [CI] = [.17, .25]), and that narcissists tend to self-enhance their agentic characteristics more than their communal characteristics. The average corrected relationship between narcissism and self-enhancement for agentic characteristics was .29 (95% CI = [.25, .33]), whereas for communal characteristics it was .05 (95% CI = [-.01, .10]). In addition, we individually summarized narcissists' self-enhancement for 10 different constructs (i.e., the Big Five, task performance, intelligence, leadership, attractiveness, and likeability). © 2015 by the Society for Personality and Social Psychology, Inc.

Trust in automation: designing for appropriate reliance.

PubMed

Lee, John D; See, Katrina A

2004-01-01

Automation is often problematic because people fail to rely upon it appropriately. Because people respond to technology socially, trust influences reliance on automation. In particular, trust guides reliance when complexity and unanticipated situations make a complete understanding of the automation impractical. This review considers trust from the organizational, sociological, interpersonal, psychological, and neurological perspectives. It considers how the context, automation characteristics, and cognitive processes affect the appropriateness of trust. The context in which the automation is used influences automation performance and provides a goal-oriented perspective to assess automation characteristics along a dimension of attributional abstraction. These characteristics can influence trust through analytic, analogical, and affective processes. The challenges of extrapolating the concept of trust in people to trust in automation are discussed. A conceptual model integrates research regarding trust in automation and describes the dynamics of trust, the role of context, and the influence of display characteristics. Actual or potential applications of this research include improved designs of systems that require people to manage imperfect automation.

On Establishing Big Data Wave Breakwaters with Analytics (Invited)

NASA Astrophysics Data System (ADS)

Riedel, M.

2013-12-01

The Research Data Alliance Big Data Analytics (RDA-BDA) Interest Group seeks to develop community based recommendations on feasible data analytics approaches to address scientific community needs of utilizing large quantities of data. RDA-BDA seeks to analyze different scientific domain applications and their potential use of various big data analytics techniques. A systematic classification of feasible combinations of analysis algorithms, analytical tools, data and resource characteristics and scientific queries will be covered in these recommendations. These combinations are complex since a wide variety of different data analysis algorithms exist (e.g. specific algorithms using GPUs of analyzing brain images) that need to work together with multiple analytical tools reaching from simple (iterative) map-reduce methods (e.g. with Apache Hadoop or Twister) to sophisticated higher level frameworks that leverage machine learning algorithms (e.g. Apache Mahout). These computational analysis techniques are often augmented with visual analytics techniques (e.g. computational steering on large-scale high performance computing platforms) to put the human judgement into the analysis loop or new approaches with databases that are designed to support new forms of unstructured or semi-structured data as opposed to the rather tradtional structural databases (e.g. relational databases). More recently, data analysis and underpinned analytics frameworks also have to consider energy footprints of underlying resources. To sum up, the aim of this talk is to provide pieces of information to understand big data analytics in the context of science and engineering using the aforementioned classification as the lighthouse and as the frame of reference for a systematic approach. This talk will provide insights about big data analytics methods in context of science within varios communities and offers different views of how approaches of correlation and causality offer complementary methods to advance in science and engineering today. The RDA Big Data Analytics Group seeks to understand what approaches are not only technically feasible, but also scientifically feasible. The lighthouse Goal of the RDA Big Data Analytics Group is a classification of clever combinations of various Technologies and scientific applications in order to provide clear recommendations to the scientific community what approaches are technicalla and scientifically feasible.

Characteristic analysis on UAV-MIMO channel based on normalized correlation matrix.

PubMed

Gao, Xi jun; Chen, Zi li; Hu, Yong Jiang

2014-01-01

Based on the three-dimensional GBSBCM (geometrically based double bounce cylinder model) channel model of MIMO for unmanned aerial vehicle (UAV), the simple form of UAV space-time-frequency channel correlation function which includes the LOS, SPE, and DIF components is presented. By the methods of channel matrix decomposition and coefficient normalization, the analytic formula of UAV-MIMO normalized correlation matrix is deduced. This formula can be used directly to analyze the condition number of UAV-MIMO channel matrix, the channel capacity, and other characteristic parameters. The simulation results show that this channel correlation matrix can be applied to describe the changes of UAV-MIMO channel characteristics under different parameter settings comprehensively. This analysis method provides a theoretical basis for improving the transmission performance of UAV-MIMO channel. The development of MIMO technology shows practical application value in the field of UAV communication.

Characteristic Analysis on UAV-MIMO Channel Based on Normalized Correlation Matrix

PubMed Central

Xi jun, Gao; Zi li, Chen; Yong Jiang, Hu

2014-01-01

Based on the three-dimensional GBSBCM (geometrically based double bounce cylinder model) channel model of MIMO for unmanned aerial vehicle (UAV), the simple form of UAV space-time-frequency channel correlation function which includes the LOS, SPE, and DIF components is presented. By the methods of channel matrix decomposition and coefficient normalization, the analytic formula of UAV-MIMO normalized correlation matrix is deduced. This formula can be used directly to analyze the condition number of UAV-MIMO channel matrix, the channel capacity, and other characteristic parameters. The simulation results show that this channel correlation matrix can be applied to describe the changes of UAV-MIMO channel characteristics under different parameter settings comprehensively. This analysis method provides a theoretical basis for improving the transmission performance of UAV-MIMO channel. The development of MIMO technology shows practical application value in the field of UAV communication. PMID:24977185

Design Characteristics Influence Performance of Clinical Prediction Rules in Validation: A Meta-Epidemiological Study

PubMed Central

Ban, Jong-Wook; Emparanza, José Ignacio; Urreta, Iratxe; Burls, Amanda

2016-01-01

Background Many new clinical prediction rules are derived and validated. But the design and reporting quality of clinical prediction research has been less than optimal. We aimed to assess whether design characteristics of validation studies were associated with the overestimation of clinical prediction rules’ performance. We also aimed to evaluate whether validation studies clearly reported important methodological characteristics. Methods Electronic databases were searched for systematic reviews of clinical prediction rule studies published between 2006 and 2010. Data were extracted from the eligible validation studies included in the systematic reviews. A meta-analytic meta-epidemiological approach was used to assess the influence of design characteristics on predictive performance. From each validation study, it was assessed whether 7 design and 7 reporting characteristics were properly described. Results A total of 287 validation studies of clinical prediction rule were collected from 15 systematic reviews (31 meta-analyses). Validation studies using case-control design produced a summary diagnostic odds ratio (DOR) 2.2 times (95% CI: 1.2–4.3) larger than validation studies using cohort design and unclear design. When differential verification was used, the summary DOR was overestimated by twofold (95% CI: 1.2 -3.1) compared to complete, partial and unclear verification. The summary RDOR of validation studies with inadequate sample size was 1.9 (95% CI: 1.2 -3.1) compared to studies with adequate sample size. Study site, reliability, and clinical prediction rule was adequately described in 10.1%, 9.4%, and 7.0% of validation studies respectively. Conclusion Validation studies with design shortcomings may overestimate the performance of clinical prediction rules. The quality of reporting among studies validating clinical prediction rules needs to be improved. PMID:26730980

Design Characteristics Influence Performance of Clinical Prediction Rules in Validation: A Meta-Epidemiological Study.

PubMed

Ban, Jong-Wook; Emparanza, José Ignacio; Urreta, Iratxe; Burls, Amanda

2016-01-01

Many new clinical prediction rules are derived and validated. But the design and reporting quality of clinical prediction research has been less than optimal. We aimed to assess whether design characteristics of validation studies were associated with the overestimation of clinical prediction rules' performance. We also aimed to evaluate whether validation studies clearly reported important methodological characteristics. Electronic databases were searched for systematic reviews of clinical prediction rule studies published between 2006 and 2010. Data were extracted from the eligible validation studies included in the systematic reviews. A meta-analytic meta-epidemiological approach was used to assess the influence of design characteristics on predictive performance. From each validation study, it was assessed whether 7 design and 7 reporting characteristics were properly described. A total of 287 validation studies of clinical prediction rule were collected from 15 systematic reviews (31 meta-analyses). Validation studies using case-control design produced a summary diagnostic odds ratio (DOR) 2.2 times (95% CI: 1.2-4.3) larger than validation studies using cohort design and unclear design. When differential verification was used, the summary DOR was overestimated by twofold (95% CI: 1.2 -3.1) compared to complete, partial and unclear verification. The summary RDOR of validation studies with inadequate sample size was 1.9 (95% CI: 1.2 -3.1) compared to studies with adequate sample size. Study site, reliability, and clinical prediction rule was adequately described in 10.1%, 9.4%, and 7.0% of validation studies respectively. Validation studies with design shortcomings may overestimate the performance of clinical prediction rules. The quality of reporting among studies validating clinical prediction rules needs to be improved.

Executive functioning in preschool children: performance on A-not-B and other delayed response format tasks.

PubMed

Espy, K A; Kaufmann, P M; McDiarmid, M D; Glisky, M L

1999-11-01

The A-not-B (AB) task has been hypothesized to measure executive/frontal lobe function; however, the developmental and measurement characteristics of this task have not been investigated. Performances on AB and comparison tasks adapted from developmental and neuroscience literature was examined in 117 preschool children (ages 23-66 months). Age significantly predicted performance on AB, Delayed Alternation, Spatial Reversal, Color Reversal, and Self-Control tasks. A four-factor analytic model best fit task performance data. AB task indices loaded on two factors with measures from the Self-Control and Delayed Alternation tasks, respectively. AB indices did not load with those from the reversal tasks despite similarities in task administration and presumed cognitive demand (working memory). These results indicate that AB is sensitive to individual differences in age-related performance in preschool children and suggest that AB performance is related to both working memory and inhibition processes in this age range.

Reversed-phase high-performance liquid chromatography of unsubstituted aminobenzoic acids

USGS Publications Warehouse

Abidi, S.L.

1989-01-01

High-performance liquid chromatographic (HPLC) characteristics of three position isomers of aminobenzoic acids (potential metabolites of important anesthetic drugs), were delineated with respect to their interactions with various mobile phases and stationary phases. HPLC with five hydrocarbonaceous phase, I?-cyclodextrin silica (CDS), macrophase MP-1 polymer (MP), macroporous polystyrene/divinylbenzene (MPD), octadecylsilica (ODS), and propylphenylsilica (PPS), yielded results explicable in terms of substituent effects derived from the bifunctional amino- and carboxy groups. For cases where mobile phases contained sulfonates or quaternary ammonium salts both having longer chain alkyls, retention of analytes on all but CDS appeared to proceed predominantly via an ion-pairing mechanism. The extent of the corresponding counter-ion effects decreased in the order: MPD > ODS > PPS > MP, while the analyte retention order paralleled thier pH2 values. On the other hand, an inverse relationship between the magnitude of capacity factors (k') and pK1 values of the title compounds was observed in experiments that produced retention data incompatible with ion-pair interaction rationales. The unique HPLC results obtained with the CDS phase are compared with those obtained with other phases.

Multicenter evaluation of the Bayer Immuno I CA 15-3 assay.

PubMed

Cheli, C D; Morris, D L; Kish, L; Goldblatt, J; Neaman, I; Allard, W J; Yeung, K K; Wu, A H; Moore, R; Chan, D W; Fritsche, H A; Schwartz, M K; Very, D L

1998-04-01

We conducted a multicenter evaluation of the analytical and clinical features of the automated Bayer Immuno 1 CA 15-3 assay and compared assay performance to two manual tests. Results of the 10-day imprecision study of the Bayer Immuno 1 assay pooled across four evaluation sites and three lots of reagent produced total CV < or = 4%. Lot-to-lot reproducibility for 26 different lots of reagents and calibrators manufactured over a 2-year period was demonstrated (CV, 1.1%). Results for the Bayer Immuno 1 assay correlated well with the Biomira TRUQUANT BR 27.29 and Centocor CA 15-3 RIAs (r > or = 0.94). The upper limit of the reference interval for the Bayer Immuno 1 assay was 35.9 kilounits/L (35.9 units/mL); values were similar for all methods. Longitudinal monitoring of healthy women yielded assay values with an average CV of 11% and 21% for the Bayer Immuno 1 and Biomira assays, respectively. The Bayer Immuno 1 assay demonstrated the analytical features, intermethod correlation, and long-term performance characteristics that are essential for longitudinal monitoring of breast cancer patients.

Assessment of passive drag in swimming by numerical simulation and analytical procedure.

PubMed

Barbosa, Tiago M; Ramos, Rui; Silva, António J; Marinho, Daniel A

2018-03-01

The aim was to compare the passive drag-gliding underwater by a numerical simulation and an analytical procedure. An Olympic swimmer was scanned by computer tomography and modelled gliding at a 0.75-m depth in the streamlined position. Steady-state computer fluid dynamics (CFD) analyses were performed on Fluent. A set of analytical procedures was selected concurrently. Friction drag (D f ), pressure drag (D pr ), total passive drag force (D f +pr ) and drag coefficient (C D ) were computed between 1.3 and 2.5 m · s -1 by both techniques. D f +pr ranged from 45.44 to 144.06 N with CFD, from 46.03 to 167.06 N with the analytical procedure (differences: from 1.28% to 13.77%). C D ranged between 0.698 and 0.622 by CFD, 0.657 and 0.644 by analytical procedures (differences: 0.40-6.30%). Linear regression models showed a very high association for D f +pr plotted in absolute values (R 2  = 0.98) and after log-log transformation (R 2  = 0.99). The C D also obtained a very high adjustment for both absolute (R 2  = 0.97) and log-log plots (R 2  = 0.97). The bias for the D f +pr was 8.37 N and 0.076 N after logarithmic transformation. D f represented between 15.97% and 18.82% of the D f +pr by the CFD, 14.66% and 16.21% by the analytical procedures. Therefore, despite the bias, analytical procedures offer a feasible way of gathering insight on one's hydrodynamics characteristics.

Vacuum ultraviolet detector for gas chromatography.

PubMed

Schug, Kevin A; Sawicki, Ian; Carlton, Doug D; Fan, Hui; McNair, Harold M; Nimmo, John P; Kroll, Peter; Smuts, Jonathan; Walsh, Phillip; Harrison, Dale

2014-08-19

Analytical performance characteristics of a new vacuum ultraviolet (VUV) detector for gas chromatography (GC) are reported. GC-VUV was applied to hydrocarbons, fixed gases, polyaromatic hydrocarbons, fatty acids, pesticides, drugs, and estrogens. Applications were chosen to feature the sensitivity and universal detection capabilities of the VUV detector, especially for cases where mass spectrometry performance has been limited. Virtually all chemical species absorb and have unique gas phase absorption cross sections in the approximately 120-240 nm wavelength range monitored. Spectra are presented, along with the ability to use software for deconvolution of overlapping signals. Some comparisons with experimental synchrotron data and computed theoretical spectra show good agreement, although more work is needed on appropriate computational methods to match the simultaneous broadband electronic and vibronic excitation initiated by the deuterium lamp. Quantitative analysis is governed by Beer-Lambert Law relationships. Mass on-column detection limits reported for representatives of different classes of analytes ranged from 15 (benzene) to 246 pg (water). Linear range measured at peak absorption for benzene was 3-4 orders of magnitude. Importantly, where absorption cross sections are known for analytes, the VUV detector is capable of absolute determination (without calibration) of the number of molecules present in the flow cell in the absence of chemical interferences. This study sets the stage for application of GC-VUV technology across a wide breadth of research areas.

Characteristics of foodborne outbreaks in which use of analytical epidemiological studies contributed to identification of suspected vehicles, European Union, 2007 to 2011.

PubMed

Schlinkmann, K M; Razum, O; Werber, D

2017-04-01

Foodborne disease outbreaks (FBDOs) occur frequently in Europe. Employing analytical epidemiological study designs increases the likelihood of identifying the suspected vehicle(s), but these studies are rarely applied in FBDO investigations. We used multivariable binary logistic regression analysis to identify characteristics of investigated FBDOs reported to the European Food Safety Authority (2007-2011) that were associated with analytical epidemiological evidence (compared to evidence from microbiological investigations/descriptive epidemiology only). The analysis was restricted to FBDO investigations, where the evidence for the suspected vehicle was considered 'strong', i.e. convincing. The presence of analytical epidemiological evidence was reported in 2012 (50%) of these 4038 outbreaks. In multivariable analysis, increasing outbreak size, number of hospitalizations, causative (i.e. aetiological) agent (whether identified and, if so, which one), and the setting in which these outbreaks occurred (e.g. geographically dispersed outbreaks) were independently associated with presence of analytical evidence. The number of investigations with reported analytical epidemiological evidence was unexpectedly high, likely indicating the need for quality assurance within the European Union foodborne outbreak reporting system, and warranting cautious interpretation of our findings. This first analysis of evidence implicating a food vehicle in FBDOs may help to inform public health authorities on when to use analytical epidemiological study designs.

Mathematical model of polyethylene pipe bending stress state

NASA Astrophysics Data System (ADS)

Serebrennikov, Anatoly; Serebrennikov, Daniil

2018-03-01

Introduction of new machines and new technologies of polyethylene pipeline installation is usually based on the polyethylene pipe flexibility. It is necessary that existing bending stresses do not lead to an irreversible polyethylene pipe deformation and to violation of its strength characteristics. Derivation of the mathematical model which allows calculating analytically the bending stress level of polyethylene pipes with consideration of nonlinear characteristics is presented below. All analytical calculations made with the mathematical model are experimentally proved and confirmed.

An analytic performance model of disk arrays and its application

NASA Technical Reports Server (NTRS)

Lee, Edward K.; Katz, Randy H.

1991-01-01

As disk arrays become widely used, tools for understanding and analyzing their performance become increasingly important. In particular, performance models can be invaluable in both configuring and designing disk arrays. Accurate analytic performance models are desirable over other types of models because they can be quickly evaluated, are applicable under a wide range of system and workload parameters, and can be manipulated by a range of mathematical techniques. Unfortunately, analytical performance models of disk arrays are difficult to formulate due to the presence of queuing and fork-join synchronization; a disk array request is broken up into independent disk requests which must all complete to satisfy the original request. We develop, validate, and apply an analytic performance model for disk arrays. We derive simple equations for approximating their utilization, response time, and throughput. We then validate the analytic model via simulation and investigate the accuracy of each approximation used in deriving the analytical model. Finally, we apply the analytical model to derive an equation for the optimal unit of data striping in disk arrays.

Bringing a transgenic crop to market: where compositional analysis fits.

PubMed

Privalle, Laura S; Gillikin, Nancy; Wandelt, Christine

2013-09-04

In the process of developing a biotechnology product, thousands of genes and transformation events are evaluated to select the event that will be commercialized. The ideal event is identified on the basis of multiple characteristics including trait efficacy, the molecular characteristics of the insert, and agronomic performance. Once selected, the commercial event is subjected to a rigorous safety evaluation taking a multipronged approach including examination of the safety of the gene and gene product - the protein, plant performance, impact of cultivating the crop on the environment, agronomic performance, and equivalence of the crop/food to conventional crops/food - by compositional analysis. The compositional analysis is composed of a comparison of the nutrient and antinutrient composition of the crop containing the event, its parental line (variety), and other conventional lines (varieties). Different geographies have different requirements for the compositional analysis studies. Parameters that vary include the number of years (seasons) and locations (environments) to be evaluated, the appropriate comparator(s), analytes to be evaluated, and statistical analysis. Specific examples of compositional analysis results will be presented.

Vibration, performance, flutter and forced response characteristics of a large-scale propfan and its aeroelastic model

NASA Technical Reports Server (NTRS)

August, Richard; Kaza, Krishna Rao V.

1988-01-01

An investigation of the vibration, performance, flutter, and forced response of the large-scale propfan, SR7L, and its aeroelastic model, SR7A, has been performed by applying available structural and aeroelastic analytical codes and then correlating measured and calculated results. Finite element models of the blades were used to obtain modal frequencies, displacements, stresses and strains. These values were then used in conjunction with a 3-D, unsteady, lifting surface aerodynamic theory for the subsequent aeroelastic analyses of the blades. The agreement between measured and calculated frequencies and mode shapes for both models is very good. Calculated power coefficients correlate well with those measured for low advance ratios. Flutter results show that both propfans are stable at their respective design points. There is also good agreement between calculated and measured blade vibratory strains due to excitation resulting from yawed flow for the SR7A propfan. The similarity of structural and aeroelastic results show that the SR7A propfan simulates the SR7L characteristics.

A Comparative Study of Single-pulse and Double-pulse Laser-Induced Breakdown Spectroscopy with Uranium-containing Samples

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

Skrodzki, P. J.; Becker, J. R.; Diwakar, P. K.

Laser-induced breakdown spectroscopy (LIBS) holds potential advantages in special nuclear material (SNM) sensing and nuclear forensics which require rapid analysis, minimal sample preparation and stand-off distance capability. SNM, such as U, however, result in crowded emission spectra with LIBS, and characteristic emission lines are challenging to discern. It is well-known that double-pulse LIBS (DPLIBS) improves the signal intensity for analytes over conventional single-pulse LIBS (SPLIBS). This study investigates U signal in a glass matrix using DPLIBS and compares to signal features obtained using SPLIBS. DPLIBS involves sequential firing of 1.06 µm Nd:YAG pre-pulse and 10.6 µm TEA CO2 heating pulsemore » in near collinear geometry. Optimization of experimental parameters including inter-pulse delay and energy follows identification of characteristic lines and signals for bulk analyte Ca and minor constituent analyte U for both DPLIBS and SPLIBS. Spatial and temporal coupling of the two pulses in the proposed DPLIBS technique yields improvements in analytical merits with negligible further damage to the sample compared to SPLIBS. Subsequently, the study discusses optimum plasma emission conditions of U lines and relative figures of merit in both SPLIBS and DPLIBS. Investigation into plasma characteristics also addresses plausible mechanisms related to observed U analyte signal variation between SPLIBS and DPLIBS.« less

Comparison of analytical and predictive methods for water, protein, fat, sugar, and gross energy in marine mammal milk.

PubMed

Oftedal, O T; Eisert, R; Barrell, G K

2014-01-01

Mammalian milks may differ greatly in composition from cow milk, and these differences may affect the performance of analytical methods. High-fat, high-protein milks with a preponderance of oligosaccharides, such as those produced by many marine mammals, present a particular challenge. We compared the performance of several methods against reference procedures using Weddell seal (Leptonychotes weddellii) milk of highly varied composition (by reference methods: 27-63% water, 24-62% fat, 8-12% crude protein, 0.5-1.8% sugar). A microdrying step preparatory to carbon-hydrogen-nitrogen (CHN) gas analysis slightly underestimated water content and had a higher repeatability relative standard deviation (RSDr) than did reference oven drying at 100°C. Compared with a reference macro-Kjeldahl protein procedure, the CHN (or Dumas) combustion method had a somewhat higher RSDr (1.56 vs. 0.60%) but correlation between methods was high (0.992), means were not different (CHN: 17.2±0.46% dry matter basis; Kjeldahl 17.3±0.49% dry matter basis), there were no significant proportional or constant errors, and predictive performance was high. A carbon stoichiometric procedure based on CHN analysis failed to adequately predict fat (reference: Röse-Gottlieb method) or total sugar (reference: phenol-sulfuric acid method). Gross energy content, calculated from energetic factors and results from reference methods for fat, protein, and total sugar, accurately predicted gross energy as measured by bomb calorimetry. We conclude that the CHN (Dumas) combustion method and calculation of gross energy are acceptable analytical approaches for marine mammal milk, but fat and sugar require separate analysis by appropriate analytic methods and cannot be adequately estimated by carbon stoichiometry. Some other alternative methods-low-temperature drying for water determination; Bradford, Lowry, and biuret methods for protein; the Folch and the Bligh and Dyer methods for fat; and enzymatic and reducing sugar methods for total sugar-appear likely to produce substantial error in marine mammal milks. It is important that alternative analytical methods be properly validated against a reference method before being used, especially for mammalian milks that differ greatly from cow milk in analyte characteristics and concentrations. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

An Analytic Approach to Projectile Motion in a Linear Resisting Medium

ERIC Educational Resources Information Center

Stewart, Sean M.

2006-01-01

The time of flight, range and the angle which maximizes the range of a projectile in a linear resisting medium are expressed in analytic form in terms of the recently defined Lambert W function. From the closed-form solutions a number of results characteristic to the motion of the projectile in a linear resisting medium are analytically confirmed,…

Nanofabrication of densely packed metal-polymer arrays for surface-enhanced Raman spectrometry.

PubMed

De Jesús, M A; Giesfeldt, K S; Oran, J M; Abu-Hatab, N A; Lavrik, N V; Sepaniak, M J

2005-12-01

A key element to improve the analytical capabilities of surface-enhanced Raman spectroscopy (SERS) resides in the performance characteristics of the SERS-active substrate. Variables such as shape, size, and homogeneous distribution of the metal nanoparticles throughout the substrate surface are important in the design of more analytically sensitive and reliable substrates. Electron-beam lithography (EBL) has emerged as a powerful tool for the systematic fabrication of substrates with periodic nanoscale features. EBL also allows the rational design of nanoscale features that are optimized to the frequency of the Raman laser source. In this work, the efficiency of EBL fabricated substrates are studied by measuring the relative SERS signals of Rhodamine 6G and 1,10-phenanthro-line adsorbed on a series of cubic, elliptical, and hexagonal nanopatterned pillars of ma-N 2403 directly coated by physical vapor deposition with 25 nm films of Ag or Au. The raw analyte SERS signals, and signals normalized to metal nanoparticle surface area or numbers of loci, are used to study the effects of nanoparticle morphology on the performance of a rapidly created, diverse collection of substrates. For the excitation wavelength used, the nanoparticle size, geometry, and orientation of the particle primary axis relative to the excitation polarization vector, and particularly the density of nanoparticles, are shown to strongly influence substrate performance. A correlation between the inverse of the magnitude of the laser backscatter passed by the spectrometer and SERS activities of the various substrate patterns is also noted and provides a simple means to evaluate possible efficient coupling of the excitation radiation to localized surface plasmons for Raman enhancement.

Analytical techniques and instrumentation: A compilation. [analytical instrumentation, materials performance, and systems analysis

NASA Technical Reports Server (NTRS)

1974-01-01

Technical information is presented covering the areas of: (1) analytical instrumentation useful in the analysis of physical phenomena; (2) analytical techniques used to determine the performance of materials; and (3) systems and component analyses for design and quality control.

42 CFR 493.845 - Standard; Toxicology.

Code of Federal Regulations, 2012 CFR

2012-10-01

... acceptable responses for each analyte in each testing event is unsatisfactory analyte performance for the... testing event. (e)(1) For any unsatisfactory analyte or test performance or testing event for reasons... any unacceptable analyte or testing event score, remedial action must be taken and documented, and the...

42 CFR 493.851 - Standard; Hematology.

Code of Federal Regulations, 2014 CFR

2014-10-01

... acceptable responses for each analyte in each testing event is unsatisfactory analyte performance for the... testing event. (e)(1) For any unsatisfactory analyte or test performance or testing event for reasons... any unacceptable analyte or testing event score, remedial action must be taken and documented, and the...

42 CFR 493.843 - Standard; Endocrinology.

Code of Federal Regulations, 2013 CFR

2013-10-01

... acceptable responses for each analyte in each testing event is unsatisfactory analyte performance for the... testing event. (e)(1) For any unsatisfactory analyte or test performance or testing event for reasons... any unacceptable analyte or testing event score, remedial action must be taken and documented, and the...

42 CFR 493.845 - Standard; Toxicology.

Code of Federal Regulations, 2014 CFR

2014-10-01

... acceptable responses for each analyte in each testing event is unsatisfactory analyte performance for the... testing event. (e)(1) For any unsatisfactory analyte or test performance or testing event for reasons... any unacceptable analyte or testing event score, remedial action must be taken and documented, and the...

42 CFR 493.845 - Standard; Toxicology.

Code of Federal Regulations, 2013 CFR

2013-10-01

... acceptable responses for each analyte in each testing event is unsatisfactory analyte performance for the... testing event. (e)(1) For any unsatisfactory analyte or test performance or testing event for reasons... any unacceptable analyte or testing event score, remedial action must be taken and documented, and the...

42 CFR 493.851 - Standard; Hematology.

Code of Federal Regulations, 2013 CFR

2013-10-01

... acceptable responses for each analyte in each testing event is unsatisfactory analyte performance for the... testing event. (e)(1) For any unsatisfactory analyte or test performance or testing event for reasons... any unacceptable analyte or testing event score, remedial action must be taken and documented, and the...

42 CFR 493.843 - Standard; Endocrinology.

Code of Federal Regulations, 2012 CFR

2012-10-01

... acceptable responses for each analyte in each testing event is unsatisfactory analyte performance for the... testing event. (e)(1) For any unsatisfactory analyte or test performance or testing event for reasons... any unacceptable analyte or testing event score, remedial action must be taken and documented, and the...

42 CFR 493.843 - Standard; Endocrinology.

Code of Federal Regulations, 2014 CFR

2014-10-01

... acceptable responses for each analyte in each testing event is unsatisfactory analyte performance for the... testing event. (e)(1) For any unsatisfactory analyte or test performance or testing event for reasons... any unacceptable analyte or testing event score, remedial action must be taken and documented, and the...

42 CFR 493.851 - Standard; Hematology.

Code of Federal Regulations, 2012 CFR

2012-10-01

... acceptable responses for each analyte in each testing event is unsatisfactory analyte performance for the... testing event. (e)(1) For any unsatisfactory analyte or test performance or testing event for reasons... any unacceptable analyte or testing event score, remedial action must be taken and documented, and the...

Distribution-centric 3-parameter thermodynamic models of partition gas chromatography.

PubMed

Blumberg, Leonid M

2017-03-31

If both parameters (the entropy, ΔS, and the enthalpy, ΔH) of the classic van't Hoff model of dependence of distribution coefficients (K) of analytes on temperature (T) are treated as the temperature-independent constants then the accuracy of the model is known to be insufficient for the needed accuracy of retention time prediction. A more accurate 3-parameter Clarke-Glew model offers a way to treat ΔS and ΔH as functions, ΔS(T) and ΔH(T), of T. A known T-centric construction of these functions is based on relating them to the reference values (ΔS ref and ΔH ref ) corresponding to a predetermined reference temperature (T ref ). Choosing a single T ref for all analytes in a complex sample or in a large database might lead to practically irrelevant values of ΔS ref and ΔH ref for those analytes that have too small or too large retention factors at T ref . Breaking all analytes in several subsets each with its own T ref leads to discontinuities in the analyte parameters. These problems are avoided in the K-centric modeling where ΔS(T) and ΔS(T) and other analyte parameters are described in relation to their values corresponding to a predetermined reference distribution coefficient (K Ref ) - the same for all analytes. In this report, the mathematics of the K-centric modeling are described and the properties of several types of K-centric parameters are discussed. It has been shown that the earlier introduced characteristic parameters of the analyte-column interaction (the characteristic temperature, T char , and the characteristic thermal constant, θ char ) are a special chromatographically convenient case of the K-centric parameters. Transformations of T-centric parameters into K-centric ones and vice-versa as well as the transformations of one set of K-centric parameters into another set and vice-versa are described. Copyright © 2017 Elsevier B.V. All rights reserved.

Performance Evaluation of Bluetooth Low Energy: A Systematic Review.

PubMed

Tosi, Jacopo; Taffoni, Fabrizio; Santacatterina, Marco; Sannino, Roberto; Formica, Domenico

2017-12-13

Small, compact and embedded sensors are a pervasive technology in everyday life for a wide number of applications (e.g., wearable devices, domotics, e-health systems, etc.). In this context, wireless transmission plays a key role, and among available solutions, Bluetooth Low Energy (BLE) is gaining more and more popularity. BLE merges together good performance, low-energy consumption and widespread diffusion. The aim of this work is to review the main methodologies adopted to investigate BLE performance. The first part of this review is an in-depth description of the protocol, highlighting the main characteristics and implementation details. The second part reviews the state of the art on BLE characteristics and performance. In particular, we analyze throughput, maximum number of connectable sensors, power consumption, latency and maximum reachable range, with the aim to identify what are the current limits of BLE technology. The main results can be resumed as follows: throughput may theoretically reach the limit of ~230 kbps, but actual applications analyzed in this review show throughputs limited to ~100 kbps; the maximum reachable range is strictly dependent on the radio power, and it goes up to a few tens of meters; the maximum number of nodes in the network depends on connection parameters, on the network architecture and specific device characteristics, but it is usually lower than 10; power consumption and latency are largely modeled and analyzed and are strictly dependent on a huge number of parameters. Most of these characteristics are based on analytical models, but there is a need for rigorous experimental evaluations to understand the actual limits.

Performance Evaluation of Bluetooth Low Energy: A Systematic Review

PubMed Central

Taffoni, Fabrizio; Santacatterina, Marco; Sannino, Roberto

2017-01-01

Small, compact and embedded sensors are a pervasive technology in everyday life for a wide number of applications (e.g., wearable devices, domotics, e-health systems, etc.). In this context, wireless transmission plays a key role, and among available solutions, Bluetooth Low Energy (BLE) is gaining more and more popularity. BLE merges together good performance, low-energy consumption and widespread diffusion. The aim of this work is to review the main methodologies adopted to investigate BLE performance. The first part of this review is an in-depth description of the protocol, highlighting the main characteristics and implementation details. The second part reviews the state of the art on BLE characteristics and performance. In particular, we analyze throughput, maximum number of connectable sensors, power consumption, latency and maximum reachable range, with the aim to identify what are the current limits of BLE technology. The main results can be resumed as follows: throughput may theoretically reach the limit of ~230 kbps, but actual applications analyzed in this review show throughputs limited to ~100 kbps; the maximum reachable range is strictly dependent on the radio power, and it goes up to a few tens of meters; the maximum number of nodes in the network depends on connection parameters, on the network architecture and specific device characteristics, but it is usually lower than 10; power consumption and latency are largely modeled and analyzed and are strictly dependent on a huge number of parameters. Most of these characteristics are based on analytical models, but there is a need for rigorous experimental evaluations to understand the actual limits. PMID:29236085

Accurate Estimate of Some Propagation Characteristics for the First Higher Order Mode in Graded Index Fiber with Simple Analytic Chebyshev Method

NASA Astrophysics Data System (ADS)

Dutta, Ivy; Chowdhury, Anirban Roy; Kumbhakar, Dharmadas

2013-03-01

Using Chebyshev power series approach, accurate description for the first higher order (LP11) mode of graded index fibers having three different profile shape functions are presented in this paper and applied to predict their propagation characteristics. These characteristics include fractional power guided through the core, excitation efficiency and Petermann I and II spot sizes with their approximate analytic formulations. We have shown that where two and three Chebyshev points in LP11 mode approximation present fairly accurate results, the values based on our calculations involving four Chebyshev points match excellently with available exact numerical results.

Development of models of the magnetorheological fluid damper

NASA Astrophysics Data System (ADS)

Kazakov, Yu. B.; Morozov, N. A.; Nesterov, S. A.

2017-06-01

The algorithm for analytical calculation of a power characteristic of magnetorheological (MR) dampers taking into account the rheological properties of MR fluid is considered. The nonlinear magnetorheological characteristics are represented by piecewise linear approximation to MR fluid areas with different viscosities. The extended calculated power characteristics of a MR damper are received and they coincide with actual results. The finite element model of a MR damper is developed; it allows carrying out the analysis of a MR damper taking into account the mutual influence of electromagnetic, hydrodynamic and thermal fields. The results of finite element simulation coincide with analytical solutions that allows using them for design development of a MR damper.

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.

Baseline experimental investigation of an electrohydrodynamically assisted heat pipe

NASA Technical Reports Server (NTRS)

Duncan, A. B.

1995-01-01

The increases in power demand and associated thermal management requirements of future space programs such as potential Lunar/Mars missions will require enhancing the operating efficiencies of thermal management devices. Currently, the use of electrohydrodynamically (EHD) assisted thermal control devices is under consideration as a potential method of increasing thermal management system capacity. The objectives of the currently described investigation included completing build-up of the EHD-Assisted Heat Pipe Test bed, developing test procedures for an experimental evaluation of the unassisted heat pipe, developing an analytical model capable of predicting the performance limits of the unassisted heat pipe, and obtaining experimental data which would define the performance characteristics of the unassisted heat pipe. The information obtained in the currently proposed study will be used in order to provide extensive comparisons with the EHD-assisted performance observations to be obtained during the continuing investigation of EHD-Assisted heat transfer devices. Through comparisons of the baseline test bed data and the EHD assisted test bed data, accurate insight into the performance enhancing characteristics of EHD augmentation may be obtained. This may lead to optimization, development, and implementation of EHD technology for future space programs.

Analytical study of the cruise performance of a class of remotely piloted, microwave-powered, high-altitude airplane platforms

NASA Technical Reports Server (NTRS)

Morris, C. E. K., Jr.

1981-01-01

Each cycle of the flight profile consists of climb while the vehicle is tracked and powered by a microwave beam, followed by gliding flight back to a minimum altitude. Parameter variations were used to define the effects of changes in the characteristics of the airplane aerodynamics, the power transmission systems, the propulsion system, and winds. Results show that wind effects limit the reduction of wing loading and increase the lift coefficient, two effective ways to obtain longer range and endurance for each flight cycle. Calculated climb performance showed strong sensitivity to some power and propulsion parameters. A simplified method of computing gliding endurance was developed.

Advanced ETC/LSS computerized analytical models, CO2 concentration. Volume 1: Summary document

NASA Technical Reports Server (NTRS)

Taylor, B. N.; Loscutoff, A. V.

1972-01-01

Computer simulations have been prepared for the concepts of C02 concentration which have the potential for maintaining a C02 partial pressure of 3.0 mmHg, or less, in a spacecraft environment. The simulations were performed using the G-189A Generalized Environmental Control computer program. In preparing the simulations, new subroutines to model the principal functional components for each concept were prepared and integrated into the existing program. Sample problems were run to demonstrate the methods of simulation and performance characteristics of the individual concepts. Comparison runs for each concept can be made for parametric values of cabin pressure, crew size, cabin air dry and wet bulb temperatures, and mission duration.

Scramjet nozzle design and analysis as applied to a highly integrated hypersonic research airplane

NASA Technical Reports Server (NTRS)

Small, W. J.; Weidner, J. P.; Johnston, P. J.

1974-01-01

The configuration and performance of the propulsion system for the hypersonic research vehicle are discussed. A study of the interactions between propulsion and aerodynamics of the highly integrated vehicle was conducted. The hypersonic research vehicle is configured to test the technology of structural and thermal protection systems concepts and the operation of the propulsion system under true flight conditions for most of the hypersonic flight regime. The subjects considered are: (1) research vehicle and scramjet engine configurations to determine fundamental engine sizing constraints, (2) analytical methods for computing airframe and propulsion system components, and (3) characteristics of a candidate nozzle to investigate vehicle stability and acceleration performance.

Modeling and performance analysis of an improved movement-based location management scheme for packet-switched mobile communication systems.

PubMed

Chung, Yun Won; Kwon, Jae Kyun; Park, Suwon

2014-01-01

One of the key technologies to support mobility of mobile station (MS) in mobile communication systems is location management which consists of location update and paging. In this paper, an improved movement-based location management scheme with two movement thresholds is proposed, considering bursty data traffic characteristics of packet-switched (PS) services. The analytical modeling for location update and paging signaling loads of the proposed scheme is developed thoroughly and the performance of the proposed scheme is compared with that of the conventional scheme. We show that the proposed scheme outperforms the conventional scheme in terms of total signaling load with an appropriate selection of movement thresholds.

Performance of 75 millimeter-bore arched outer-race ball bearings

NASA Technical Reports Server (NTRS)

Coe, H. H.; Hamrock, B. J.

1976-01-01

An investigation was performed to determine the operating characteristics of 75-mm bore, arched outer-race bearings, and to compare the data with those for a similar, but conventional, deep groove ball bearing. Further, results of an analytical study, made using a computer program developed previously, were compared with the experimental data. Bearings were tested up to 28,000 rpm shaft speed with a load of 2200 N (500 lb). The amount of arching was 0.13, 0.25, and 0.51 mm (.005, .010, and .020 in.). All bearings operated satisfactorily. The outer-race temperatures and the torques, however, were consistently higher for the arched bearings than for the conventional bearing.

Performance of 75-millimeter bore arched outer-race ball bearings

NASA Technical Reports Server (NTRS)

Coe, H. H.; Hamrock, B. J.

1976-01-01

An investigation was performed to determine the operating characteristics of 75-mm bore, arched outer-race bearings, and to compare the data with those for a similar, but conventional, deep groove ball bearing. Further, results of an analytical study, made using a computer program developed previously, were compared with the experimental data. Bearings were tested up to 28,000 rpm shaft speed with a load of 2,200 N (500 lb). The amount of arching was 0.13, 0.25, and 0.51 mm (0.005, 0.010, and 0.020 in). All bearings operated satisfactorily. The outer-race temperatures and the torques, however, were consistently higher for the arched bearings than for the conventional bearings

Analysis and design of a standardized control module for switching regulators

NASA Astrophysics Data System (ADS)

Lee, F. C.; Mahmoud, M. F.; Yu, Y.; Kolecki, J. C.

1982-07-01

Three basic switching regulators: buck, boost, and buck/boost, employing a multiloop standardized control module (SCM) were characterized by a common small signal block diagram. Employing the unified model, regulator performances such as stability, audiosusceptibility, output impedance, and step load transient are analyzed and key performance indexes are expressed in simple analytical forms. More importantly, the performance characteristics of all three regulators are shown to enjoy common properties due to the unique SCM control scheme which nullifies the positive zero and provides adaptive compensation to the moving poles of the boost and buck/boost converters. This allows a simple unified design procedure to be devised for selecting the key SCM control parameters for an arbitrarily given power stage configuration and parameter values, such that all regulator performance specifications can be met and optimized concurrently in a single design attempt.

Edge softening of the Shuttle TPS strain isolation pad. [Thermal Protection System

NASA Technical Reports Server (NTRS)

Ransone, P. O.; Rummler, D. R.

1982-01-01

Tensile tests and an analytical investigation were performed to characterize the edge softening behavior of the strain isolation pad (SIP) between the Orbiter skin and thermal protection system. The tensile tests were carried out with varying sizes of disk-shaped specimens bonded between aluminum disks. The specimens strength and stiffness were determined on the basis of specimen size, and an analytical model of the microstructural stress-strain characteristics was developed. Strength and stiffness were found to decrease near the free edges because through-the-thickness fibers located there were not anchored. No size dependence at maximum load was observed in specimens between 0.75-4.0 in. thick. In-plane and out-of-plane coupling in deformation was detected. The model gave accurate predictions of the tensile behavior of the SIP as a function of distance to a free edge.

Investigation of flow fields within large scale hypersonic inlet models

NASA Technical Reports Server (NTRS)

Gnos, A. V.; Watson, E. C.; Seebaugh, W. R.; Sanator, R. J.; Decarlo, J. P.

1973-01-01

Analytical and experimental investigations were conducted to determine the internal flow characteristics in model passages representative of hypersonic inlets for use at Mach numbers to about 12. The passages were large enough to permit measurements to be made in both the core flow and boundary layers. The analytical techniques for designing the internal contours and predicting the internal flow-field development accounted for coupling between the boundary layers and inviscid flow fields by means of a displacement-thickness correction. Three large-scale inlet models, each having a different internal compression ratio, were designed to provide high internal performance with an approximately uniform static-pressure distribution at the throat station. The models were tested in the Ames 3.5-Foot Hypersonic Wind Tunnel at a nominal free-stream Mach number of 7.4 and a unit free-stream Reynolds number of 8.86 X one million per meter.

Instrumentation for analytical scale supercritical fluid chromatography.

PubMed

Berger, Terry A

2015-11-20

Analytical scale supercritical fluid chromatography (SFC) is largely a sub-discipline of high performance liquid chromatography (HPLC), in that most of the hardware and software can be used for either technique. The aspects that separate the 2 techniques stem from the use of carbon dioxide (CO2) as the main component of the mobile phase in SFC. The high compressibility and low viscosity of CO2 mean that pumps, and autosamplers designed for HPLC either need to be modified or an alternate means of dealing with compressibility needs to be found. The inclusion of a back pressure regulator and a high pressure flow cell for any UV-Vis detector are also necessary. Details of the various approaches, problems and solutions are described. Characteristics, such as adiabatic vs. isothermal compressibility, thermal gradients, and refractive index issues are dealt with in detail. Copyright © 2015 Elsevier B.V. All rights reserved.

Evaluation of a reconfigurable portable instrument for copper determination based on luminescent carbon dots.

PubMed

Salinas-Castillo, Alfonso; Morales, Diego P; Lapresta-Fernández, Alejandro; Ariza-Avidad, María; Castillo, Encarnación; Martínez-Olmos, Antonio; Palma, Alberto J; Capitan-Vallvey, Luis Fermin

2016-04-01

A portable reconfigurable platform for copper (Cu(II)) determination based on luminescent carbon dot (Cdots) quenching is described. The electronic setup consists of a light-emitting diode (LED) as the carbon dot optical exciter and a photodiode as a light-to-current converter integrated in the same instrument. Moreover, the overall analog conditioning is simply performed with one integrated solution, a field-programmable analog array (FPAA), which makes it possible to reconfigure the filter and gain stages in real time. This feature provides adaptability to use the platform as an analytical probe for carbon dots coming from different batches with some variations in luminescence characteristics. The calibration functions obtained that fit a modified Stern-Volmer equation were obtained using luminescence signals from Cdots quenching by Cu(II). The analytical applicability of the reconfigurable portable instrument for Cu(II) using Cdots has been successfully demonstrated in tap water analysis.

Research on optical biosensor with up-converting phosphor marker

NASA Astrophysics Data System (ADS)

Zhao, Yongkai; Zhou, Lei; Wang, Jing; Huang, Lihua; Yan, Zhongqiang; Huang, Huijie; Yang, Ruifu; Liu, Lei; Ren, Bingqiang; Wang, Xiangzhao

2006-08-01

An optical biosensor with up-converting phosphor (UCP) marker is developed for the sensitive rapid immunoassay to the specific biomolecule. UCP can emit visible light when excited by infrared light. Through detecting and analyzing the content of UCP particles on the test strip after immunoreaction, the concentration of target analyte in the sample can be obtained. The detection sensitivity to plague IgG is better than 5 ng/ml; to plague FI-Ab is better than 100 pg/ml; to plague Yersinia pestis cell is better than 3*10^(4) CFU/ml. Good linear response characteristics and an excellent correlation (R2>=0.95) have been verified by quantitative detection results. In the practical application, detection results to 167 analytic samples have an excellent consistency with those obtained by reverse hemagglutination test. The up-converting phosphor technology (UPT) based biosensor has stable, reliable, and sensitive performances. It can meet the need of various bioassay applications.

Task-based image quality evaluation of iterative reconstruction methods for low dose CT using computer simulations

NASA Astrophysics Data System (ADS)

Xu, Jingyan; Fuld, Matthew K.; Fung, George S. K.; Tsui, Benjamin M. W.

2015-04-01

Iterative reconstruction (IR) methods for x-ray CT is a promising approach to improve image quality or reduce radiation dose to patients. The goal of this work was to use task based image quality measures and the channelized Hotelling observer (CHO) to evaluate both analytic and IR methods for clinical x-ray CT applications. We performed realistic computer simulations at five radiation dose levels, from a clinical reference low dose D0 to 25% D0. A fixed size and contrast lesion was inserted at different locations into the liver of the XCAT phantom to simulate a weak signal. The simulated data were reconstructed on a commercial CT scanner (SOMATOM Definition Flash; Siemens, Forchheim, Germany) using the vendor-provided analytic (WFBP) and IR (SAFIRE) methods. The reconstructed images were analyzed by CHOs with both rotationally symmetric (RS) and rotationally oriented (RO) channels, and with different numbers of lesion locations (5, 10, and 20) in a signal known exactly (SKE), background known exactly but variable (BKEV) detection task. The area under the receiver operating characteristic curve (AUC) was used as a summary measure to compare the IR and analytic methods; the AUC was also used as the equal performance criterion to derive the potential dose reduction factor of IR. In general, there was a good agreement in the relative AUC values of different reconstruction methods using CHOs with RS and RO channels, although the CHO with RO channels achieved higher AUCs than RS channels. The improvement of IR over analytic methods depends on the dose level. The reference dose level D0 was based on a clinical low dose protocol, lower than the standard dose due to the use of IR methods. At 75% D0, the performance improvement was statistically significant (p < 0.05). The potential dose reduction factor also depended on the detection task. For the SKE/BKEV task involving 10 lesion locations, a dose reduction of at least 25% from D0 was achieved.

EVALUATIONS ON ASR DAMAGE OF CONCRETE STRUCTURE AND ITS STRUCTURAL PERFORMANCE

NASA Astrophysics Data System (ADS)

Ueda, Naoshi; Nakamura, Hikaru; Kunieda, Minoru; Maeno, Hirofumi; Morishit, Noriaki; Asai, Hiroshi

In this paper, experiments and finite element analyses were conducted in order to evaluate effects of ASR on structural performance of RC and PC structures. From the experimental results, it was confirmed that the ASR expansion was affected by the restraint of reinforcement and the magnitude of prestress. The material properties of concrete damaged by ASR had anisotropic characteristics depending on the degree of ASR expansion. Therefore, when the structural performance of RC and PC structures were evaluated by using the material properties of core concrete, the direction and place where cylinder specimens were cored should be considered. On the other hand, by means of proposed analytical method, ASR expansion behaviors of RC and PC beams and changing of their structural performance were evaluated. As the results, it was confirmed that PC structure had much advantage comparing with RC structure regarding the structural performance under ASR damage because of restraint by prestress against the ASR.

Assessment of Thermal Performance of Functionally Graded Materials in Longitudinal Fins

NASA Astrophysics Data System (ADS)

Hassanzadeh, R.; Bilgili, M.

2018-01-01

Assessment of the thermal characteristics of materials in heat exchangers with longitudinal fins is performed in the case where a conventional homogeneous material of a longitudinal fin is replaced by a functionally graded one, in which the fin material properties, such as the conductivity, are assumed to be graded as linear and power-law functions along the normal axis from the fin base to the fin tip. The resulting equations are calculated under two (Dirichlet and Neumann) boundary conditions. The equations are solved by an approximate analytical method with the use of the mean value theorem. The results show that the inhomogeneity index of a functionally graded material plays an important role for the thermal energy characteristics in such heat exchangers. In addition, it is observed that the use of such a material in longitudinal fins enhances the rate of heat transfer between the fin surface and surrounding fluid. Hopefully, the results obtained in the study will arouse interest of designers in heat exchange industry.

Space Cryogenics Workshop, University of Wisconsin, Madison, June 22, 23, 1987

NASA Technical Reports Server (NTRS)

1988-01-01

Papers are presented on liquid helium servicing from the Space Station, performance estimates in the Superfluid Helium On-Orbit Transfer Flight Experiment, an analytical study of He II flow characteristics in the SHOOT transfer line, a Dewar to Dewar model for superfluid helium transfer, and mechanical pumps for superfluid helium transfer in space. Attention is also given to the cavitation characteristics of a small centrifugal pump in He I and He II, turbulent flow pressure drop in various He II transfer system components, slip effects associated with Knudsen transport phenomena in porous media, and an integrated fountain effect pump device for fluid management at low gravity. Other papers are on liquid/vapor phase separation in He-4 using electric fields, an enclosed capillary device for low-gravity management of He II, cavitation in flowing superfluid helium, the long-term performance of the passive thermal control systems of the IRAS spacecraft, and a novel approach to supercritical helium flight cryostat support structures.

The Multi-Player Performance-Enhancing Drug Game

PubMed Central

Haugen, Kjetil K.; Nepusz, Tamás; Petróczi, Andrea

2013-01-01

This paper extends classical work on economics of doping into a multi-player game setting. Apart from being among the first papers formally formulating and analysing a multi-player doping situation, we find interesting results related to different types of Nash-equilibria (NE). Based mainly on analytic results, we claim at least two different NE structures linked to the choice of prize functions. Linear prize functions provide NEs characterised by either everyone or nobody taking drugs, while non-linear prize functions lead to qualitatively different NEs with significantly more complex predictive characteristics. PMID:23691018

Introduction to Loop Heat Pipes

NASA Technical Reports Server (NTRS)

Ku, Jentung

2015-01-01

This is the presentation file for the short course Introduction to Loop Heat Pipes, to be conducted at the 2015 Thermal Fluids and Analysis Workshop, August 3-7, 2015, Silver Spring, Maryland. This course will discuss operating principles and performance characteristics of a loop heat pipe. Topics include: 1) pressure profiles in the loop; 2) loop operating temperature; 3) operating temperature control; 4) loop startup; 4) loop shutdown; 5) loop transient behaviors; 6) sizing of loop components and determination of fluid inventory; 7) analytical modeling; 8) examples of flight applications; and 9) recent LHP developments.

An analytical study for the design of advanced rotor airfoils

NASA Technical Reports Server (NTRS)

Kemp, L. D.

1973-01-01

A theoretical study has been conducted to design and evaluate two airfoils for helicopter rotors. The best basic shape, designed with a transonic hodograph design method, was modified to meet subsonic criteria. One airfoil had an additional constraint for low pitching-moment at the transonic design point. Airfoil characteristics were predicted. Results of a comparative analysis of helicopter performance indicate that the new airfoils will produce reduced rotor power requirements compared to the NACA 0012. The hodograph design method, written in CDC Algol, is listed and described.

Storyline Visualizations of Eye Tracking of Movie Viewing

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

Balint, John T.; Arendt, Dustin L.; Blaha, Leslie M.

Storyline visualizations offer an approach that promises to capture the spatio-temporal characteristics of individual observers and simultaneously illustrate emerging group behaviors. We develop a visual analytics approach to parsing, aligning, and clustering fixation sequences from eye tracking data. Visualization of the results captures the similarities and differences across a group of observers performing a common task. We apply our storyline approach to visualize gaze patterns of people watching dynamic movie clips. Storylines mitigate some of the shortcomings of existent spatio-temporal visualization techniques and, importantly, continue to highlight individual observer behavioral dynamics.

Ku-band signal design study. [space shuttle orbiter data processing network

NASA Technical Reports Server (NTRS)

Rubin, I.

1978-01-01

Analytical tools, methods and techniques for assessing the design and performance of the space shuttle orbiter data processing system (DPS) are provided. The computer data processing network is evaluated in the key areas of queueing behavior synchronization and network reliability. The structure of the data processing network is described as well as the system operation principles and the network configuration. The characteristics of the computer systems are indicated. System reliability measures are defined and studied. System and network invulnerability measures are computed. Communication path and network failure analysis techniques are included.

Fourier analysis of surface plasmon waves launched from single nanohole and nanohole arrays: unraveling tip-induced effects.

PubMed

Chang, Y C; Chu, J Y; Wang, T J; Lin, M W; Yeh, J T; Wang, J K

2008-01-21

The authors report the investigation of surface plasmon waves (SPW) generated by single nanohole and nanohole arrays. Scattering-type scanning near-field microscopy is used to directly observe near-field distribution. The images after Fourier transformation display characteristic patterns that match with the derived analytic formula. The correspondence helps to identify the role of the scanning tip in generating SPW, making possible of the removal of this tip-induced effect. This study provides a means to perform in-depth investigation on surface plasmon polaritons.

Analytical design of a parasitic-loading digital speed controller for a 400-hertz turbine driven alternator

NASA Technical Reports Server (NTRS)

Ingle, B. D.; Ryan, J. P.

1972-01-01

A design for a solid-state parasitic speed controller using digital logic was analyzed. Parasitic speed controllers are used in space power electrical generating systems to control the speed of turbine-driven alternators within specified limits. The analysis included the performance characteristics of the speed controller and the generation of timing functions. The speed controller using digital logic applies step loads to the alternator. The step loads conduct for a full half wave starting at either zero or 180 electrical degrees.

Variation of the transmittance spectrum of a polymer cladding optical fibre for the influence of hydrocarbons and changes in temperature

NASA Astrophysics Data System (ADS)

Santoyo, A. T.; Shlyagin, M. G.; Mendieta, F. J.; Spirin, V.; de Rivera, L. N.

2005-12-01

We develop an analysis of the behavior of an evanescent field fiber optic sensor under different conditions for its optimization. This paper presents results of an experimental study of the spectral characteristics of a polymer cladding optical fiber exposed to different analytes. The measurements were performed in the spectral interval from 1100 to 1800 nanometers in a temperature range from 5 to 50 degrees C. Influence of ambient temperature on the optical fiber transmittance was found to be strongly dependent on wavelength.

Portfolio optimization problem with nonidentical variances of asset returns using statistical mechanical informatics.

PubMed

Shinzato, Takashi

2016-12-01

The portfolio optimization problem in which the variances of the return rates of assets are not identical is analyzed in this paper using the methodology of statistical mechanical informatics, specifically, replica analysis. We defined two characteristic quantities of an optimal portfolio, namely, minimal investment risk and investment concentration, in order to solve the portfolio optimization problem and analytically determined their asymptotical behaviors using replica analysis. Numerical experiments were also performed, and a comparison between the results of our simulation and those obtained via replica analysis validated our proposed method.

Portfolio optimization problem with nonidentical variances of asset returns using statistical mechanical informatics

NASA Astrophysics Data System (ADS)

Shinzato, Takashi

2016-12-01

The portfolio optimization problem in which the variances of the return rates of assets are not identical is analyzed in this paper using the methodology of statistical mechanical informatics, specifically, replica analysis. We defined two characteristic quantities of an optimal portfolio, namely, minimal investment risk and investment concentration, in order to solve the portfolio optimization problem and analytically determined their asymptotical behaviors using replica analysis. Numerical experiments were also performed, and a comparison between the results of our simulation and those obtained via replica analysis validated our proposed method.

Technology and benefits of aircraft counter rotation propellers

NASA Technical Reports Server (NTRS)

Strack, W. C.; Knip, G.; Weisbrich, A. L.; Godston, J.; Bradley, E.

1981-01-01

Results are reported of a NASA sponsored analytical investigation into the merits of advanced counter rotation propellers for Mach 0.80 commercial transport application. Propeller and gearbox performance, acoustics, vibration characteristics, weight, cost and maintenance requirements for a variety of design parameters and special features were considered. Fuel savings in the neighborhood of 8 percent relative to single rotation configurations are feasible through swirl recovery and lighter gearboxes. This is the net gain which includes a 5 percent acoustic treatment weight penalty to offset the broader frequency spectrum noise produced by counter rotation blading.

Noise characteristics of upper surface blown configurations: Analytical Studies

NASA Technical Reports Server (NTRS)

Reddy, N. N.; Tibbetts, J. G.; Pennock, A. P.; Tam, C. K. W.

1978-01-01

Noise and flow results of upper surface blown configurations were analyzed. The dominant noise source mechanisms were identified from experimental data. From far-field noise data for various geometric and operational parameters, an empirical noise prediction program was developed and evaluated by comparing predicted results with experimental data from other tests. USB aircraft compatibility studies were conducted using the described noise prediction and a cruise performance data base. A final design aircraft was selected and theory was developed for the noise from the trailing edge wake assuming it as a highly sheared layer.

Evaluation of Copper-1,3,5-benzenetricarboxylate Metal-organic Framework (Cu-MOF) as a Selective Sorbent for Lewis-base Analytes

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

Harvey, Scott D.; Eckberg, Alison D.; Thallapally, Praveen K.

2011-09-01

The metal-organic framework Cu-BTC was evaluated for its ability to selectively interact with Lewis-base analytes, including explosives, by examining retention on GC columns packed with Chromosorb W HP that contained 3.0% SE-30 along with various loadings of Cu-BTC. SEM images of the support material showed the characteristic Cu-BTC crystals embedded in the SE-30 coating on the diatomaceous support. Results indicated that the Cu-BTC-containing stationary phase had limited thermal stability (220°C) and strong general retention for analytes. Kováts index calculations showed selective retention (amounting to about 300 Kováts units) relative to n-alkanes for many small Lewis-base analytes on a column thatmore » contained 0.75% Cu-BTC compared to an SE-30 control. Short columns that contained lower loadings of Cu-BTC (0.10%) were necessary to elute explosives and related analytes; however, selectivity was not observed for aromatic compounds (including nitroaromatics) or nitroalkanes. Observed retention characteristics are discussed.« less

Analytical characteristics and comparative evaluation of Aptima HIV-1 Quant Dx assay with Ampliprep/COBAS TaqMan HIV-1 test v2.0.

PubMed

Hatzakis, Angelos; Papachristou, Helen; Nair, Sangeetha J; Fortunko, Jacqueline; Foote, Tracy; Kim, HeeCheol; Peling, Tashi L; Worlock, Andrew J

2016-10-21

Quantitation of HIV-RNA is critically important for diagnosis, prognosis, treatment, monitoring and assessment of infectivity in HIV-1 infection. The objective of this study was to assess performance characteristics of the Aptima HIV-1 Quant Dx assay (Aptima), a new transcription mediated amplification (TMA), fully integrated and automated assay from Hologic Inc., San Diego, CA, USA. The analytical sensitivity, analytical specificity, precision and detection of HIV-1 subtypes were tested based on commercially available international standards or panels. A selected group of 244 anti-HIV-1 (+) plasma samples was used for comparison with Roche COBAS Ampliprep/COBAS TaqMan HIV- 1 test v2.0 (Roche CAP/CTM), (Roche Molecular Systems, Pleasanton, CA). The 50 and 95 % limit of detection were estimated at 4.9 (95 % CI 3.9-5.7) and 17.6 (15.2-21.2) IU/mL respectively. The specificity was found 99.83 (99.06-99.97) %. The standard deviations and coefficient of variations for panels with 50 and 100 copies/mL (1.7 and 2 log copies/mL) were 0.14 log copies/mL (8.67 %CV) and 0.18 log copies/mL (9.91 %CV) respectively. The detection rate for Aptima and Roche assays was 220/244 (90.2 %) and 217/244 (88.9 %) respectively. The Aptima assay is a sensitive, specific, precise and accurate test for measuring HIV-1 viral loads and for the detection of HIV-1 infections.

Numerical and Experimental Investigations on Mechanical Behavior of Composite Corrugated Core

NASA Astrophysics Data System (ADS)

Dayyani, Iman; Ziaei-Rad, Saeed; Salehi, Hamid

2012-06-01

Tensile and flexural characteristics of corrugated laminate panels were studied using numerical and analytical methods and compared with experimental data. Prepreg laminates of glass fiber plain woven cloth were hand-laid by use of a heat gun to ease the creation of the panel. The corrugated panels were then manufactured by using a trapezoidal machined aluminium mould. First, a series of simple tension tests were performed on standard samples to evaluate the material characteristics. Next, the corrugated panels were subjected to tensile and three-point bending tests. The force-displacement graphs were recorded. Numerical and analytical solutions were proposed to simulate the mechanical behavior of the panels. In order to model the energy dissipation due to delamination phenomenon observed in tensile tests in all members of corrugated core, plastic behavior was assigned to the whole geometry, not only to the corner regions. Contrary to the literature, it is shown that the three-stage mechanical behavior of composite corrugated core is not confined to aramid reinforced corrugated laminates and can be observed in other types such as fiber glass. The results reveal that the mechanical behavior of the core in tension is sensitive to the variation of core height. In addition, for the first time, the behavior of composite corrugated core was studied and verified in bending. Finally, the analytical and numerical results were validated by comparing them with experimental data. A good degree of correlation was observed which showed the suitability of the finite element model for predicting the mechanical behavior of corrugated laminate panels.

Combining oxytocin administration and positive emotion inductions: Examining social perception and analytical performance.

PubMed

Human, Lauren J; Thorson, Katherine R; Woolley, Joshua D; Mendes, Wendy Berry

2017-04-01

Intranasal administration of the hypothalamic neuropeptide oxytocin (OT) has, in some studies, been associated with positive effects on social perception and cognition. Similarly, positive emotion inductions can improve a range of perceptual and performance-based behaviors. In this exploratory study, we examined how OT administration and positive emotion inductions interact in their associations with social and analytical performance. Participants (N=124) were randomly assigned to receive an intranasal spray of OT (40IU) or placebo and then viewed one of three videos designed to engender one of the following emotion states: social warmth, pride, or an affectively neutral state. Following the emotion induction, participants completed social perception and analytical tasks. There were no significant main effects of OT condition on social perception tasks, failing to replicate prior research, or on analytical performance. Further, OT condition and positive emotion inductions did not interact with each other in their associations with social perception performance. However, OT condition and positive emotion manipulations did significantly interact in their associations with analytical performance. Specifically, combining positive emotion inductions with OT administration was associated with worse analytical performance, with the pride induction no longer benefiting performance and the warmth induction resulting in worse performance. In sum, we found little evidence for main or interactive effects of OT on social perception but preliminary evidence that OT administration may impair analytical performance when paired with positive emotion inductions. Copyright © 2017 Elsevier Inc. All rights reserved.

Evaluation of analytical performance based on partial order methodology.

PubMed

Carlsen, Lars; Bruggemann, Rainer; Kenessova, Olga; Erzhigitov, Erkin

2015-01-01

Classical measurements of performances are typically based on linear scales. However, in analytical chemistry a simple scale may be not sufficient to analyze the analytical performance appropriately. Here partial order methodology can be helpful. Within the context described here, partial order analysis can be seen as an ordinal analysis of data matrices, especially to simplify the relative comparisons of objects due to their data profile (the ordered set of values an object have). Hence, partial order methodology offers a unique possibility to evaluate analytical performance. In the present data as, e.g., provided by the laboratories through interlaboratory comparisons or proficiency testings is used as an illustrative example. However, the presented scheme is likewise applicable for comparison of analytical methods or simply as a tool for optimization of an analytical method. The methodology can be applied without presumptions or pretreatment of the analytical data provided in order to evaluate the analytical performance taking into account all indicators simultaneously and thus elucidating a "distance" from the true value. In the present illustrative example it is assumed that the laboratories analyze a given sample several times and subsequently report the mean value, the standard deviation and the skewness, which simultaneously are used for the evaluation of the analytical performance. The analyses lead to information concerning (1) a partial ordering of the laboratories, subsequently, (2) a "distance" to the Reference laboratory and (3) a classification due to the concept of "peculiar points". Copyright © 2014 Elsevier B.V. All rights reserved.

Development of a positive corona from a long grounded wire in a growing thunderstorm field

NASA Astrophysics Data System (ADS)

Mokrov, M. S.; Raizer, Yu P.; Bazelyan, E. M.

2013-11-01

The properties of a non-stationary corona initiated from a long grounded wire suspended horizontally above the ground and coronating in a slowly varying thundercloud electric field are studied. A two-dimensional (2D) model of the corona is developed. On the basis of this model, characteristics of the corona produced by a lightning protection wire are calculated under thunderstorm conditions. The corona characteristics are also found by using approximate analytical and quasi-one-dimensional numerical models. The results of these models agree reasonably well with those obtained from the 2D simulation. This allows one to estimate the corona parameters without recourse to the cumbersome simulation. This work was performed with a view to study the efficiency of lightning protection wires later on.

Structural Test and Analysis of a Hybrid Inflatable Antenna

NASA Technical Reports Server (NTRS)

Gaspar, James L.; Mann, Troy; Sreekantamurthy, Tham; Behun, Vaughn

2007-01-01

NASA is developing ultra-lightweight structures technology for communication antennas for space missions. One of the research goals is to evaluate the structural characteristics of inflatable and rigidizable antennas through test and analysis. Being able to test and analyze the structural characteristics of a full scale antenna is important to enable the simulation of various mission scenarios to determine system performance in space. Recent work completed to evaluate a Hybrid Inflatable Antenna concept will be discussed. Tests were completed on a 2-m prototype to optimize its static shape and identify its modal dynamics that are important for analytical model validation. These test results were used to evaluate a preliminary finite element model of the antenna, and this model development and correlation activity is also described in the paper.

Investigation of a New Flux-Modulated Permanent Magnet Brushless Motor for EVs

PubMed Central

Gu, Lingling; Luo, Yong; Han, Xuedong

2014-01-01

This paper presents a flux-modulated direct drive (FMDD) motor. The key is to integrate the magnetic gear with the PM motor while removing the gear inner-rotor. Hence, the proposed FMDD motor can achieve the low-speed high-torque output and high-speed compact design requirements as well as high-torque density with a simple structure. The output power equation is analytically derived. By using finite element analysis (FEA), the static characteristics of the proposed motor are obtained. Based on these characteristics, the system mathematical model can be established. Hence, the evaluation of system performances is conducted by computer simulation using the Matlab/Simulink. A prototype is designed and built for experimentation. Experimental results are given to verify the theoretical analysis and simulation. PMID:24883405

Investigation of a new flux-modulated permanent magnet brushless motor for EVs.

PubMed

Fan, Ying; Gu, Lingling; Luo, Yong; Han, Xuedong; Cheng, Ming

2014-01-01

This paper presents a flux-modulated direct drive (FMDD) motor. The key is to integrate the magnetic gear with the PM motor while removing the gear inner-rotor. Hence, the proposed FMDD motor can achieve the low-speed high-torque output and high-speed compact design requirements as well as high-torque density with a simple structure. The output power equation is analytically derived. By using finite element analysis (FEA), the static characteristics of the proposed motor are obtained. Based on these characteristics, the system mathematical model can be established. Hence, the evaluation of system performances is conducted by computer simulation using the Matlab/Simulink. A prototype is designed and built for experimentation. Experimental results are given to verify the theoretical analysis and simulation.

An ecological perspective of science and math academic achievement among African American students

NASA Astrophysics Data System (ADS)

Stewart, Endya Bentley

Using data from the National Education Longitudinal Study of 1988 (NELS:88), path analytic procedures were performed to test an ecological model of the effects of family, individual and school characteristics on the academic African American students. A distinctive study is the inclusion of school computer use in the model. The study results show that several of the variables directly or indirectly affected 12th grade academic achievement. Furthermore, most of the individual influence variables were directly related to 12 th grade achievement. Two surprising findings from this study were the insignificant effects of family income and school computer use on 12 th grade achievement. Overall, the findings support the notion that family, individual, and school characteristics are important predictors of academic success among African American students.

A meta-analytic examination of the goal orientation nomological net.

PubMed

Payne, Stephanie C; Youngcourt, Satoris S; Beaubien, J Matthew

2007-01-01

The authors present an empirical review of the literature concerning trait and state goal orientation (GO). Three dimensions of GO were examined: learning, prove performance, and avoid performance along with presumed antecedents and proximal and distal consequences of these dimensions. Antecedent variables included cognitive ability, implicit theory of intelligence, need for achievement, self-esteem, general self-efficacy, and the Big Five personality characteristics. Proximal consequences included state GO, task-specific self-efficacy, self-set goal level, learning strategies, feedback seeking, and state anxiety. Distal consequences included learning, academic performance, task performance, and job performance. Generally speaking, learning GO was positively correlated, avoid performance GO was negatively correlated, and prove performance GO was uncorrelated with these variables. Consistent with theory, state GO tended to have stronger relationships with the distal consequences than did trait GO. Finally, using a meta-correlation matrix, the authors found that trait GO predicted job performance above and beyond cognitive ability and personality. These results demonstrate the value of GO to organizational researchers. 2007 APA, all rights reserved

Simplified procedures for correlation of experimentally measured and predicted thrust chamber performance

NASA Technical Reports Server (NTRS)

Powell, W. B.

1973-01-01

Thrust chamber performance is evaluated in terms of an analytical model incorporating all the loss processes that occur in a real rocket motor. The important loss processes in the real thrust chamber were identified, and a methodology and recommended procedure for predicting real thrust chamber vacuum specific impulse were developed. Simplified equations for the calculation of vacuum specific impulse are developed to relate the delivered performance (both vacuum specific impulse and characteristic velocity) to the ideal performance as degraded by the losses corresponding to a specified list of loss processes. These simplified equations enable the various performance loss components, and the corresponding efficiencies, to be quantified separately (except that interaction effects are arbitrarily assigned in the process). The loss and efficiency expressions presented can be used to evaluate experimentally measured thrust chamber performance, to direct development effort into the areas most likely to yield improvements in performance, and as a basis to predict performance of related thrust chamber configurations.

A Methodology for Determining Statistical Performance Compliance for Airborne Doppler Radar with Forward-Looking Turbulence Detection Capability

NASA Technical Reports Server (NTRS)

Bowles, Roland L.; Buck, Bill K.

2009-01-01

The objective of the research developed and presented in this document was to statistically assess turbulence hazard detection performance employing airborne pulse Doppler radar systems. The FAA certification methodology for forward looking airborne turbulence radars will require estimating the probabilities of missed and false hazard indications under operational conditions. Analytical approaches must be used due to the near impossibility of obtaining sufficient statistics experimentally. This report describes an end-to-end analytical technique for estimating these probabilities for Enhanced Turbulence (E-Turb) Radar systems under noise-limited conditions, for a variety of aircraft types, as defined in FAA TSO-C134. This technique provides for one means, but not the only means, by which an applicant can demonstrate compliance to the FAA directed ATDS Working Group performance requirements. Turbulence hazard algorithms were developed that derived predictive estimates of aircraft hazards from basic radar observables. These algorithms were designed to prevent false turbulence indications while accurately predicting areas of elevated turbulence risks to aircraft, passengers, and crew; and were successfully flight tested on a NASA B757-200 and a Delta Air Lines B737-800. Application of this defined methodology for calculating the probability of missed and false hazard indications taking into account the effect of the various algorithms used, is demonstrated for representative transport aircraft and radar performance characteristics.

[Simultaneous determination of four alkaloids in Corydalis decumbens (Thunb.) Pers. by high performance liquid chromatography-tandem mass spectrometry].

PubMed

Shen, Yan; Han, Chao; Liu, Cuiping; Zhou, Yongfang; Xia, Biqi; Zhu, Zhenou; Liu, Aili

2011-02-01

A method for the analysis of 4 alkaloids in Corydalis decumbens (Thunb.) Pers. was developed by high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-MS/MS). The sample was extracted in methanol by ultrasonic, filtered and diluted with methanol for further analysis. The analysis was performed on a C18 column (150 mm x 2.1 mm, 3.5 microm) using a gradient elution program with the mobile phase of 0.2% acetic acid solution and acetonitrile. The analyte was determined by an electrospray ionization tandem mass spectrometry in multiple reactions monitoring (MRM) mode. The qualitative and quantitative analyses were based on the retention times and characteristic ion pairs consisting of one parent ion and two fragment ions of the analyte. The limits of detection (LODs) for 4 alkaloids were in the range of 0.02 - 0.2 microg/L, and the limits of quantification (LOQs) were in the range of 0.07 - 0.66 microg/L. The average recoveries were in the range of 93.6% - 103.5% for 4 alkaloids with the relative standard deviations below 3.8%. This method is reliable, sensitive and reproducible, and it can be used for the quality control of Corydalis decumbens (Thunb.) Pers. sample.

Selection of reference standard during method development using the analytical hierarchy process.

PubMed

Sun, Wan-yang; Tong, Ling; Li, Dong-xiang; Huang, Jing-yi; Zhou, Shui-ping; Sun, Henry; Bi, Kai-shun

2015-03-25

Reference standard is critical for ensuring reliable and accurate method performance. One important issue is how to select the ideal one from the alternatives. Unlike the optimization of parameters, the criteria of the reference standard are always immeasurable. The aim of this paper is to recommend a quantitative approach for the selection of reference standard during method development based on the analytical hierarchy process (AHP) as a decision-making tool. Six alternative single reference standards were assessed in quantitative analysis of six phenolic acids from Salvia Miltiorrhiza and its preparations by using ultra-performance liquid chromatography. The AHP model simultaneously considered six criteria related to reference standard characteristics and method performance, containing feasibility to obtain, abundance in samples, chemical stability, accuracy, precision and robustness. The priority of each alternative was calculated using standard AHP analysis method. The results showed that protocatechuic aldehyde is the ideal reference standard, and rosmarinic acid is about 79.8% ability as the second choice. The determination results successfully verified the evaluation ability of this model. The AHP allowed us comprehensive considering the benefits and risks of the alternatives. It was an effective and practical tool for optimization of reference standards during method development. Copyright © 2015 Elsevier B.V. All rights reserved.

Geospatial Analytics in Retail Site Selection and Sales Prediction.

PubMed

Ting, Choo-Yee; Ho, Chiung Ching; Yee, Hui Jia; Matsah, Wan Razali

2018-03-01

Studies have shown that certain features from geography, demography, trade area, and environment can play a vital role in retail site selection, largely due to the impact they asserted on retail performance. Although the relevant features could be elicited by domain experts, determining the optimal feature set can be intractable and labor-intensive exercise. The challenges center around (1) how to determine features that are important to a particular retail business and (2) how to estimate retail sales performance given a new location? The challenges become apparent when the features vary across time. In this light, this study proposed a nonintervening approach by employing feature selection algorithms and subsequently sales prediction through similarity-based methods. The results of prediction were validated by domain experts. In this study, data sets from different sources were transformed and aggregated before an analytics data set that is ready for analysis purpose could be obtained. The data sets included data about feature location, population count, property type, education status, and monthly sales from 96 branches of a telecommunication company in Malaysia. The finding suggested that (1) optimal retail performance can only be achieved through fulfillment of specific location features together with the surrounding trade area characteristics and (2) similarity-based method can provide solution to retail sales prediction.

Development of a quantitative LC-MS/MS analytical method coupled with turbulent flow chromatography for digoxin for the in vitro P-gp inhibition assay.

PubMed

Smalley, James; Marino, Anthony M; Xin, Baomin; Olah, Timothy; Balimane, Praveen V

2007-07-01

Caco-2 cells, the human colon carcinoma cells, are typically used for screening compounds for their permeability characteristics and P-glycoprotein (P-gp) interaction potential during discovery and development. The P-gp inhibition of test compounds is assessed by performing bi-directional permeability studies with digoxin, a well established P-gp substrate probe. Studies performed with digoxin alone as well as digoxin in presence of test compounds as putative inhibitors constitute the P-gp inhibition assay used to assess the potential liability of discovery compounds. Radiolabeled (3)H-digoxin is commonly used in such studies followed by liquid scintillation counting. This manuscript describes the development of a sensitive, accurate, and reproducible LC-MS/MS method for analysis of digoxin and its internal standard digitoxin using an on-line extraction turbulent flow chromatography coupled to tandem mass spectrometric detection that is amendable to high throughput with use of 96-well plates. The standard curve for digoxin was linear between 10 nM and 5000 nM with regression coefficient (R(2)) of 0.99. The applicability and reliability of the analysis method was evaluated by successful demonstration of efflux ratio (permeability B to A over permeability A to B) greater than 10 for digoxin in Caco-2 cells. Additional evaluations were performed on 13 marketed compounds by conducting inhibition studies in Caco-2 cells using classical P-gp inhibitors (ketoconazole, cyclosporin, verapamil, quinidine, saquinavir etc.) and comparing the results to historical data with (3)H-digoxin studies. Similarly, P-gp inhibition studies with LC-MS/MS analytical method for digoxin were also performed for 21 additional test compounds classified as negative, moderate, and potent P-gp inhibitors spanning multiple chemo types and results compared with the historical P-gp inhibition data from the (3)H-digoxin studies. A very good correlation coefficient (R(2)) of 0.89 between the results from the two analytical methods affords an attractive LC-MS/MS analytical option for labs that need to conduct the P-gp inhibition assay without using radiolabeled compounds.

A critical evaluation of the Beckman Coulter Access hsTnI: Analytical performance, reference interval and concordance.

PubMed

Pretorius, Carel J; Tate, Jillian R; Wilgen, Urs; Cullen, Louise; Ungerer, Jacobus P J

2018-05-01

We investigated the analytical performance, outlier rate, carryover and reference interval of the Beckman Coulter Access hsTnI in detail and compared it with historical and other commercial assays. We compared the imprecision, detection capability, analytical sensitivity, outlier rate and carryover against two previous Access AccuTnI assay versions. We established the reference interval with stored samples from a previous study and compared the concordances and variances with the Access AccuTnI+3 as well as with two commercial assays. The Access hsTnI had excellent analytical sensitivity with the calibration slope 5.6 times steeper than the Access AccuTnI+3. The detection capability was markedly improved with the SD of the blank 0.18-0.20 ng/L, LoB 0.29-0.33 ng/L and LoD 0.58-0.69 ng/L. All the reference interval samples had a result above the LoB value. At a mean concentration of 2.83 ng/L the SD was 0.28 ng/L (CV 9.8%). Carryover (0.005%) and outlier (0.046%) rates were similar to the Access AccuTnI+3. The combined male and female 99th percentile reference interval was 18.2 ng/L (90% CI 13.2-21.1 ng/L). Concordance amongst the assays was poor with only 16.7%, 19.6% and 15.2% of samples identified by all 4 assays as above the 99th, 97.5th and 95th percentiles. Analytical imprecision was a minor contributor to the observed variances between assays. The Beckman Coulter Access hsTnI assay has excellent analytical sensitivity and precision characteristics close to zero. This allows cTnI measurement in all healthy individuals and the capability to identify numerically small differences between serial samples as statistically significant. Concordance in healthy individuals remains poor amongst assays. Crown Copyright © 2018. Published by Elsevier Inc. All rights reserved.

Organic materials able to detect analytes

NASA Technical Reports Server (NTRS)

Swager, Timothy M. (Inventor); Zhu, Zhengguo (Inventor); Bulovic, Vladimir (Inventor); Rose, Aimee (Inventor); Madigan, Conor Francis (Inventor)

2012-01-01

The present invention generally relates to polymers with lasing characteristics that allow the polymers to be useful in detecting analytes. In one aspect, the polymer, upon an interaction with an analyte, may exhibit a change in a lasing characteristic that can be determined in some fashion. For example, interaction of an analyte with the polymer may affect the ability of the polymer to reach an excited state that allows stimulated emission of photons to occur, which may be determined, thereby determining the analyte. In another aspect, the polymer, upon interaction with an analyte, may exhibit a change in stimulated emission that is at least 10 times greater with respect to a change in the spontaneous emission of the polymer upon interaction with the analyte. The polymer may be a conjugated polymer in some cases. In one set of embodiments, the polymer includes one or more hydrocarbon side chains, which may be parallel to the polymer backbone in some instances. In another set of embodiments, the polymer may include one or more pendant aromatic rings. In yet another set of embodiments, the polymer may be substantially encapsulated in a hydrocarbon. In still another set of embodiments, the polymer may be substantially resistant to photobleaching. In certain aspects, the polymer may be useful in the detection of explosive agents, such as 2,4,6-trinitrotoluene (TNT) and 2,4-dinitrotoluene (DNT).

An analytical model for bio-electronic organic field-effect transistor sensors

NASA Astrophysics Data System (ADS)

Macchia, Eleonora; Giordano, Francesco; Magliulo, Maria; Palazzo, Gerardo; Torsi, Luisa

2013-09-01

A model for the electrical characteristics of Functional-Bio-Interlayer Organic Field-Effect Transistors (FBI-OFETs) electronic sensors is here proposed. Specifically, the output current-voltage characteristics of a streptavidin (SA) embedding FBI-OFET are modeled by means of the analytical equations of an enhancement mode p-channel OFET modified according to an ad hoc designed equivalent circuit that is also independently simulated with pspice. An excellent agreement between the model and the experimental current-voltage output characteristics has been found upon exposure to 5 nM of biotin. A good agreement is also found with the SA OFET parameters graphically extracted from the device transfer I-V curves.

An analytical approach to the forensic identification of different classes of new psychoactive substances (NPSs) in seized materials.

PubMed

Strano Rossi, Sabina; Odoardi, Sara; Gregori, Adolfo; Peluso, Giuseppe; Ripani, Luigi; Ortar, Giorgio; Serpelloni, Giovanni; Romolo, Francesco Saverio

2014-09-15

New psychoactive substances (NPSs) are rapidly spreading worldwide, and forensic laboratories are often requested to identify new substances for which no reference standards or analytical data are available. This article describes an analytical approach that was adopted in Italy by a few collaborative centres of the Italian Early Warning System for Drugs, which has contributed many alerts for the identification of different classes of NPSs in the last 24 months. Seized crystals and powders were initially analysed via single quadrupole gas chromatography/mass spectrometry (GC/MS), followed by liquid chromatography/high-resolution mass spectrometry (LC/HRMS) in the positive electrospray ionisation (ESI) mode at 100,000 full width at half maximum resolution (FWHM) without fragmentation to elucidate the elemental compositions of unknown molecules. Different fragmentation voltages during LC/HRMS were applied to study the accurate masses of the obtained characteristic fragments. Nuclear magnetic resonance (NMR) analyses were performed to identify specific isomers when necessary. Some interesting examples of unknown NPSs from seizures later identified in our laboratories are reported, with special focus on those cases where analytical standards were not available during analyses. These cases include cathinones, such as 3-methylmethcathinone (3-MMC), methylone, bk-MBDB (butylone), 4-methylethcathinone (4-MEC), flephedrone, methylenedioxypyrovalerone (MDPV) and pentedrone, methoxetamine, apinaca or AKB48, benzydamine, meta-chlorophenylpiperazine (m-CPP), 5-MeO-N,N-dialkyl tryptamines, such as 5-MeO-DALT and 5-MeOMIPT, benzofurans, such as 6-APB and 4-APB, and diphenidine (identified for the first time in Europe). The identification of NPSs in confiscated materials was successfully achieved via GC/MS coupled with LC/HRMS and, in a few cases, NMR analyses. The availability of GC/MS libraries is of great assistance in the identification of new drugs. Alternatively, the study of characteristic molecule fragments combined with the determination of their accurate masses can be a useful approach to identify unknown samples not previously analysed. Copyright © 2014 John Wiley & Sons, Ltd.

Structural response of bead-stiffened thermoplastic shear webs

NASA Technical Reports Server (NTRS)

Rouse, Marshall

1991-01-01

The results of an experimental and analytical study of the structural response and failure characteristics of selected bead-stiffened thermoplastic shear-webs are presented. Results are given for specimens with one stiffeneer, with two stiffeners, and different stiffener geometries. Selected analytical results that were obtained with the Computational Structural Mechanics (CSM) Testbed computer code are presented. Analytical results that describe normal and transverse shear stress are also presented.

Green analytical chemistry introduction to chloropropanols determination at no economic and analytical performance costs?

PubMed

Jędrkiewicz, Renata; Orłowski, Aleksander; Namieśnik, Jacek; Tobiszewski, Marek

2016-01-15

In this study we perform ranking of analytical procedures for 3-monochloropropane-1,2-diol determination in soy sauces by PROMETHEE method. Multicriteria decision analysis was performed for three different scenarios - metrological, economic and environmental, by application of different weights to decision making criteria. All three scenarios indicate capillary electrophoresis-based procedure as the most preferable. Apart from that the details of ranking results differ for these three scenarios. The second run of rankings was done for scenarios that include metrological, economic and environmental criteria only, neglecting others. These results show that green analytical chemistry-based selection correlates with economic, while there is no correlation with metrological ones. This is an implication that green analytical chemistry can be brought into laboratories without analytical performance costs and it is even supported by economic reasons. Copyright © 2015 Elsevier B.V. All rights reserved.

Cylindrical optical resonators: fundamental properties and bio-sensing characteristics

NASA Astrophysics Data System (ADS)

Khozeymeh, Foroogh; Razaghi, Mohammad

2018-04-01

In this paper, detailed theoretical analysis of cylindrical resonators is demonstrated. As illustrated, these kinds of resonators can be used as optical bio-sensing devices. The proposed structure is analyzed using an analytical method based on Lam's approximation. This method is systematic and has simplified the tedious process of whispering-gallery mode (WGM) wavelength analysis in optical cylindrical biosensors. By this method, analysis of higher radial orders of high angular momentum WGMs has been possible. Using closed-form analytical equations, resonance wavelengths of higher radial and angular order WGMs of TE and TM polarization waves are calculated. It is shown that high angular momentum WGMs are more appropriate for bio-sensing applications. Some of the calculations are done using a numerical non-linear Newton method. A perfect match of 99.84% between the analytical and the numerical methods has been achieved. In order to verify the validity of the calculations, Meep simulations based on the finite difference time domain (FDTD) method are performed. In this case, a match of 96.70% between the analytical and FDTD results has been obtained. The analytical predictions are in good agreement with other experimental work (99.99% match). These results validate the proposed analytical modelling for the fast design of optical cylindrical biosensors. It is shown that by extending the proposed two-layer resonator structure analyzing scheme, it is possible to study a three-layer cylindrical resonator structure as well. Moreover, by this method, fast sensitivity optimization in cylindrical resonator-based biosensors has been possible. Sensitivity of the WGM resonances is analyzed as a function of the structural parameters of the cylindrical resonators. Based on the results, fourth radial order WGMs, with a resonator radius of 50 μm, display the most bulk refractive index sensitivity of 41.50 (nm/RIU).

Characteristics of steady vibration in a rotating hub-beam system

NASA Astrophysics Data System (ADS)

Zhao, Zhen; Liu, Caishan; Ma, Wei

2016-02-01

A rotating beam features a puzzling character in which its frequencies and modal shapes may vary with the hub's inertia and its rotating speed. To highlight the essential nature behind the vibration phenomena, we analyze the steady vibration of a rotating Euler-Bernoulli beam with a quasi-steady-state stretch. Newton's law is used to derive the equations governing the beam's elastic motion and the hub's rotation. A combination of these equations results in a nonlinear partial differential equation (PDE) that fully reflects the mutual interaction between the two kinds of motion. Via the Fourier series expansion within a finite interval of time, we reduce the PDE into an infinite system of a nonlinear ordinary differential equation (ODE) in spatial domain. We further nondimensionalize the ODE and discretize it via a difference method. The frequencies and modal shapes of a general rotating beam are then determined numerically. For a low-speed beam where the ignorance of geometric stiffening is feasible, the beam's vibration characteristics are solved analytically. We validate our numerical method and the analytical solutions by comparing with either the past experiments or the past numerical findings reported in existing literature. Finally, systematic simulations are performed to demonstrate how the beam's eigenfrequencies vary with the hub's inertia and rotating speed.

Modeling and Analysis of Energy Conservation Scheme Based on Duty Cycling in Wireless Ad Hoc Sensor Network

PubMed Central

Chung, Yun Won; Hwang, Ho Young

2010-01-01

In sensor network, energy conservation is one of the most critical issues since sensor nodes should perform a sensing task for a long time (e.g., lasting a few years) but the battery of them cannot be replaced in most practical situations. For this purpose, numerous energy conservation schemes have been proposed and duty cycling scheme is considered the most suitable power conservation technique, where sensor nodes alternate between states having different levels of power consumption. In order to analyze the energy consumption of energy conservation scheme based on duty cycling, it is essential to obtain the probability of each state. In this paper, we analytically derive steady state probability of sensor node states, i.e., sleep, listen, and active states, based on traffic characteristics and timer values, i.e., sleep timer, listen timer, and active timer. The effect of traffic characteristics and timer values on the steady state probability and energy consumption is analyzed in detail. Our work can provide sensor network operators guideline for selecting appropriate timer values for efficient energy conservation. The analytical methodology developed in this paper can be extended to other energy conservation schemes based on duty cycling with different sensor node states, without much difficulty. PMID:22219676

Integration of Magnetic Bead-Based Cell Selection into Complex Isolations

PubMed Central

2018-01-01

Magnetic bead-based analyte capture has emerged as a ubiquitous method in cell isolation, enabling the highly specific capture of target populations through simple magnetic manipulation. To date, no “one-size fits all” magnetic bead has been widely adopted leading to an overwhelming number of commercial beads. Ultimately, the ideal bead is one that not only facilitates cell isolation but also proves compatible with the widest range of downstream applications and analytic endpoints. Despite the diverse offering of sizes, coatings, and conjugation chemistries, few studies exist to benchmark the performance characteristics of different commercially available beads; importantly, these bead characteristics ultimately determine the ability of a bead to integrate into the user’s assay. In this report, we evaluate bead-based cell isolation considerations, approaches, and results across a subset of commercially available magnetic beads (Dynabeads FlowComps, Dynabeads CELLection, GE Healthcare Sera-Mag SpeedBeads streptavidin-blocked magnetic particles, Dynabeads M-270s, Dynabeads M-280s) to compare and contrast both capture-specific traits (i.e., purity, capture efficacy, and contaminant isolations) and endpoint compatibility (i.e., protein localization, fluorescence imaging, and nucleic acid extraction). We identify specific advantages and contexts of use in which distinct bead products may facilitate experimental goals and integrate into downstream applications. PMID:29732449

Boron-doped diamond electrode: synthesis, characterization, functionalization and analytical applications.

PubMed

Luong, John H T; Male, Keith B; Glennon, Jeremy D

2009-10-01

In recent years, conductive diamond electrodes for electrochemical applications have been a major focus of research and development. The impetus behind such endeavors could be attributed to their wide potential window, low background current, chemical inertness, and mechanical durability. Several analytes can be oxidized by conducting diamond compared to other carbon-based materials before the breakdown of water in aqueous electrolytes. This is important for detecting and/or identifying species in solution since oxygen and hydrogen evolution do not interfere with the analysis. Thus, conductive diamond electrodes take electrochemical detection into new areas and extend their usefulness to analytes which are not feasible with conventional electrode materials. Different types of diamond electrodes, polycrystalline, microcrystalline, nanocrystalline and ultrananocrystalline, have been synthesized and characterized. Of particular interest is the synthesis of boron-doped diamond (BDD) films by chemical vapor deposition on various substrates. In the tetrahedral diamond lattice, each carbon atom is covalently bonded to its neighbors forming an extremely robust crystalline structure. Some carbon atoms in the lattice are substituted with boron to provide electrical conductivity. Modification strategies of doped diamond electrodes with metallic nanoparticles and/or electropolymerized films are of importance to impart novel characteristics or to improve the performance of diamond electrodes. Biofunctionalization of diamond films is also feasible to foster several useful bioanalytical applications. A plethora of opportunities for nanoscale analytical devices based on conducting diamond is anticipated in the very near future.

Topiramate: A Review of Analytical Approaches for the Drug Substance, Its Impurities and Pharmaceutical Formulations.

PubMed

Pinto, Eduardo Costa; Dolzan, Maressa Danielli; Cabral, Lucio Mendes; Armstrong, Daniel W; de Sousa, Valéria Pereira

2016-02-01

An important step during the development of high-performance liquid chromatography (HPLC) methods for quantitative analysis of drugs is choosing the appropriate detector. High sensitivity, reproducibility, stability, wide linear range, compatibility with gradient elution, non-destructive detection of the analyte and response unaffected by changes in the temperature/flow are some of the ideal characteristics of a universal HPLC detector. Topiramate is an anticonvulsant drug mainly used for the treatment of different types of seizures and prophylactic treatment of migraine. Different analytical approaches to quantify topiramate by HPLC have been described because of the lack of chromophoric moieties on its structure, such as derivatization with fluorescent moieties and UV-absorbing moieties, conductivity detection, evaporative light scattering detection, refractive index detection, chemiluminescent nitrogen detection and MS detection. Some methods for the determination of topiramate by capillary electrophoresis and gas chromatography have also been published. This systematic review provides a description of the main analytical methods presented in the literature to analyze topiramate in the drug substance and in pharmaceutical formulations. Each of these methods is briefly discussed, especially considering the detector used with HPLC. In addition, this article presents a review of the data available regarding topiramate stability, degradation products and impurities. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Analytical procedure for the determination of Ethyl Lauroyl Arginate (LAE) to assess the kinetics and specific migration from a new antimicrobial active food packaging.

PubMed

Pezo, Davinson; Navascués, Beatriz; Salafranca, Jesús; Nerín, Cristina

2012-10-01

Ethyl Lauroyl Arginate (LAE) is a cationic tensoactive compound, soluble in water, with a wide activity spectrum against moulds and bacteria. LAE has been incorporated as antimicrobial agent into packaging materials for food contact and these materials require to comply with the specific migration criteria. In this paper, one analytical procedure has been developed and optimized for the analysis of LAE in food simulants after the migrations tests. It consists of the formation of an ionic pair between LAE and the inorganic complex Co(SCN)(4)(2-) in aqueous solution, followed by a liquid-liquid extraction in a suitable organic solvent and further UV-Vis absorbance measurement. In order to evaluate possible interferences, the ionic pair has been also analyzed by high performance liquid chromatography with UV-Vis detection. Both procedures provided similar analytical characteristics, with linear ranges from 1.10 to 25.00 mg kg(-1), linearity higher than 0.9886, limits of detection and quantification of 0.33 and 1.10 mg kg(-1), respectively, accuracy better than 1% as relative error and precision better than 3.6% expressed as RSD. Optimization of analytical techniques, thermal and chemical stability of LAE, as well as migration kinetics of LAE from experimental active packaging are reported and discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

Modeling of phonon scattering in n-type nanowire transistors using one-shot analytic continuation technique

NASA Astrophysics Data System (ADS)

Bescond, Marc; Li, Changsheng; Mera, Hector; Cavassilas, Nicolas; Lannoo, Michel

2013-10-01

We present a one-shot current-conserving approach to model the influence of electron-phonon scattering in nano-transistors using the non-equilibrium Green's function formalism. The approach is based on the lowest order approximation (LOA) to the current and its simplest analytic continuation (LOA+AC). By means of a scaling argument, we show how both LOA and LOA+AC can be easily obtained from the first iteration of the usual self-consistent Born approximation (SCBA) algorithm. Both LOA and LOA+AC are then applied to model n-type silicon nanowire field-effect-transistors and are compared to SCBA current characteristics. In this system, the LOA fails to describe electron-phonon scattering, mainly because of the interactions with acoustic phonons at the band edges. In contrast, the LOA+AC still well approximates the SCBA current characteristics, thus demonstrating the power of analytic continuation techniques. The limits of validity of LOA+AC are also discussed, and more sophisticated and general analytic continuation techniques are suggested for more demanding cases.

Demonstration and Characterization of Biomolecular Enrichment on Microfluidic Aptamer-Functionalized Surfaces

PubMed Central

Nguyen, Thai Huu; Pei, Renjun; Stojanovic, Milan; Lin, Qiao

2010-01-01

This paper demonstrates and systematically characterizes the enrichment of biomolecular compounds using aptamer-functionalized surfaces within a microfluidic device. The device consists of a microchamber packed with aptamer-functionalized microbeads and integrated with a microheater and temperature sensor to enable thermally controlled binding and release of biomolecules by the aptamer. We first present an equilibrium binding-based analytical model to understand the enrichment process. The characteristics of the aptamer-analyte binding and enrichment are then experimentally studied, using adenosine monophosphate (AMP) and a specific RNA aptamer as a model system. The temporal process of AMP binding to the aptamer is found to be primarily determined by the aptamer-AMP binding kinetics. The temporal process of aptamer-AMP dissociation at varying temperatures is also obtained and observed to occur relatively rapidly (< 2 s). The specificity of the enrichment is next confirmed by performing selective enrichment of AMP from a sample containing biomolecular impurities. Finally, we investigate the enrichment of AMP by either discrete or continuous introduction of a dilute sample into the microchamber, demonstrating enrichment factors ranging from 566 to 686×, which agree with predictions of the analytical model. PMID:21765612

Eye movement dysfunction in first-degree relatives of patients with schizophrenia: a meta-analytic evaluation of candidate endophenotypes.

PubMed

Calkins, Monica E; Iacono, William G; Ones, Deniz S

2008-12-01

Several forms of eye movement dysfunction (EMD) are regarded as promising candidate endophenotypes of schizophrenia. Discrepancies in individual study results have led to inconsistent conclusions regarding particular aspects of EMD in relatives of schizophrenia patients. To quantitatively evaluate and compare the candidacy of smooth pursuit, saccade and fixation deficits in first-degree biological relatives, we conducted a set of meta-analytic investigations. Among 18 measures of EMD, memory-guided saccade accuracy and error rate, global smooth pursuit dysfunction, intrusive saccades during fixation, antisaccade error rate and smooth pursuit closed-loop gain emerged as best differentiating relatives from controls (standardized mean differences ranged from .46 to .66), with no significant differences among these measures. Anticipatory saccades, but no other smooth pursuit component measures were also increased in relatives. Visually-guided reflexive saccades were largely normal. Moderator analyses examining design characteristics revealed few variables affecting the magnitude of the meta-analytically observed effects. Moderate effect sizes of relatives v. controls in selective aspects of EMD supports their endophenotype potential. Future work should focus on facilitating endophenotype utility through attention to heterogeneity of EMD performance, relationships among forms of EMD, and application in molecular genetics studies.

An isocratic HPLC method for the simultaneous determination of cholesterol, cardiolipin, and DOPC in lyophilized lipids and liposomal formulations.

PubMed

Simonzadeh, Ninus

2009-04-01

Phospholipids, such as 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), and 1,1',2,2'-tetramyristoyl cardiolipin, along with cholesterol, form liposomes in aqueous media and have been investigated at NeoPharm (Lake Bluff, IL) as drug-delivery systems. To accurately assess the effectiveness of various formulations involving the use of aforementioned phospholipids and cholesterol, their quantitative determination is essential. An isocratic high-performance liquid chromatographic method for the simultaneous determination of cholesterol, cardiolipin, and DOPC in various pharmaceutical formulations containing the active drug substance has consequently been developed and is presented here. The current method utilizes an ASTEC-diol analytical column and is shown to be stability-indicating and free from interference from any of the formulation excipients, such as sucrose, sodium chloride, and sodium lactate. The analytes are detected using an evaporative light scattering detector (Alltech or Polymer Laboratories). The quantitation of each lipid component is performed using non-linear regression analysis. The retention characteristics of the analytes are examined as a function of eluent composition (e.g., pH, salt content, organic to aqueous phase ratio) and column temperature. The method was validated and was found to be sensitive, specific, rugged, and cost-effective. The current method provides enhanced chromatographic separation for lipid components as well as degradation products as compared to similar methods reported in the literature. It is also inherently simpler than other similar methods reported in the literature that typically use complex gradient elution.

Capillary Driven Flows Along Differentially Wetted Interior Corners

NASA Technical Reports Server (NTRS)

Golliher, Eric L. (Technical Monitor); Nardin, C. L.; Weislogel, M. M.

2005-01-01

Closed-form analytic solutions useful for the design of capillary flows in a variety of containers possessing interior corners were recently collected and reviewed. Low-g drop tower and aircraft experiments performed at NASA to date show excellent agreement between theory and experiment for perfectly wetting fluids. The analytical expressions are general in terms of contact angle, but do not account for variations in contact angle between the various surfaces within the system. Such conditions may be desirable for capillary containment or to compute the behavior of capillary corner flows in containers consisting of different materials with widely varying wetting characteristics. A simple coordinate rotation is employed to recast the governing system of equations for flows in containers with interior corners with differing contact angles on the faces of the corner. The result is that a large number of capillary driven corner flows may be predicted with only slightly modified geometric functions dependent on corner angle and the two (or more) contact angles of the system. A numerical solution is employed to verify the new problem formulation. The benchmarked computations support the use of the existing theoretical approach to geometries with variable wettability. Simple experiments to confirm the theoretical findings are recommended. Favorable agreement between such experiments and the present theory may argue well for the extension of the analytic results to predict fluid performance in future large length scale capillary fluid systems for spacecraft as well as for small scale capillary systems on Earth.

Analytical difficulties facing today's regulatory laboratories: issues in method validation.

PubMed

MacNeil, James D

2012-08-01

The challenges facing analytical laboratories today are not unlike those faced in the past, although both the degree of complexity and the rate of change have increased. Challenges such as development and maintenance of expertise, maintenance and up-dating of equipment, and the introduction of new test methods have always been familiar themes for analytical laboratories, but international guidelines for laboratories involved in the import and export testing of food require management of such changes in a context which includes quality assurance, accreditation, and method validation considerations. Decisions as to when a change in a method requires re-validation of the method or on the design of a validation scheme for a complex multi-residue method require a well-considered strategy, based on a current knowledge of international guidance documents and regulatory requirements, as well the laboratory's quality system requirements. Validation demonstrates that a method is 'fit for purpose', so the requirement for validation should be assessed in terms of the intended use of a method and, in the case of change or modification of a method, whether that change or modification may affect a previously validated performance characteristic. In general, method validation involves method scope, calibration-related parameters, method precision, and recovery. Any method change which may affect method scope or any performance parameters will require re-validation. Some typical situations involving change in methods are discussed and a decision process proposed for selection of appropriate validation measures. © 2012 John Wiley & Sons, Ltd.

[Determination of carcinogenic aromatic amines derived from azo colorants in plastic components of electrical and electronic products by high performance liquid chromatography-mass spectrometry].

PubMed

Niu, Zengyuan; Luo, Xin; Ye, Xiwen; Wang, Huihui; Li, Jingying

2014-01-01

A study for the simultaneous determination of 21 primary aromatic amines derived from the reduction of the azo colorants in plastic components of electrical and electronic products was conducted. Organic solvents were used to dissolve or swell the plastics to release the azo dyes existing in the plastic components. The azo colorants were reduced to aromatic amines under strong reducing condition of dithionite. Aromatic amines were extracted with methyl tert-butyl ether. Methanol-water (1: 1, v/v) was used to concentrate the extract to constant-volume for HPLC-MS analysis. The analytes were separated on a ZORBAX Eclipse XDB C18 column using the gradient elution with acetonitrile and 0.1% (v/v) formic acid aqueous solution at a flow rate of 0.6 mL/min. The analyte confirmation was performed using retention time and characteristic ions in selected ion monitoring (SIM) mode. The correlation coefficients (r) of all the standard curves were more than 0.998, and the limits of quantification of the analytes were 0.5 mg/kg. The recoveries were 60.1% - 129.5% for the 21 aromatic amines with the RSDs not more than 14.0% except for a few compounds. The results showed that the banned azo colorants in the plastic products can be analyzed qualitatively and quantitatively through reductive conversion into aromatic amines. In addition, this method has high accuracy and good precision.

What information on measurement uncertainty should be communicated to clinicians, and how?

PubMed

Plebani, Mario; Sciacovelli, Laura; Bernardi, Daniela; Aita, Ada; Antonelli, Giorgia; Padoan, Andrea

2018-02-02

The communication of laboratory results to physicians and the quality of reports represent fundamental requirements of the post-analytical phase in order to assure the right interpretation and utilization of laboratory information. Accordingly, the International Standard for clinical laboratories accreditation (ISO 15189) requires that "laboratory reports shall include the information necessary for the interpretation of the examination results". Measurement uncertainty (MU) is an inherent property of any quantitative measurement result which express the lack of knowledge of the true value and quantify the uncertainty of a result, incorporating the factors known to influence it. Even if the MU is not included in the report attributes of ISO 15189 and cannot be considered a post-analytical requirement, it is suggested as an information which should facilitate an appropriate interpretation of quantitative results (quantity values). Therefore, MU has two intended uses: for laboratory professionals, it gives information about the quality of measurements, providing evidence of the compliance with analytical performance characteristics; for physicians (and patients) it may help in interpretation of measurement results, especially when values are compared with reference intervals or clinical decision limits, providing objective information. Here we describe the way that MU should be added to laboratory reports in order to facilitate the interpretation of laboratory results and connecting efforts performed within laboratory to provide more accurate and reliable results with a more objective tool for their interpretation by physicians. Copyright © 2018 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Toward an integrative theory of training motivation: a meta-analytic path analysis of 20 years of research.

PubMed

Colquitt, J A; LePine, J A; Noe, R A

2000-10-01

This article meta-analytically summarizes the literature on training motivation, its antecedents, and its relationships with training outcomes such as declarative knowledge, skill acquisition, and transfer. Significant predictors of training motivation and outcomes included individual characteristics (e.g., locus of control, conscientiousness, anxiety, age, cognitive ability, self-efficacy, valence, job involvement) and situational characteristics (e.g., climate). Moreover, training motivation explained incremental variance in training outcomes beyond the effects of cognitive ability. Meta-analytic path analyses further showed that the effects of personality, climate, and age on training outcomes were only partially mediated by self-efficacy, valence, and job involvement. These findings are discussed in terms of their practical significance and their implications for an integrative theory of training motivation.

MPD Thruster Performance Analytic Models

NASA Technical Reports Server (NTRS)

Gilland, James; Johnston, Geoffrey

2003-01-01

Magnetoplasmadynamic (MPD) thrusters are capable of accelerating quasi-neutral plasmas to high exhaust velocities using Megawatts (MW) of electric power. These characteristics make such devices worthy of consideration for demanding, far-term missions such as the human exploration of Mars or beyond. Assessment of MPD thrusters at the system and mission level is often difficult due to their status as ongoing experimental research topics rather than developed thrusters. However, in order to assess MPD thrusters utility in later missions, some adequate characterization of performance, or more exactly, projected performance, and system level definition are required for use in analyses. The most recent physical models of self-field MPD thrusters have been examined, assessed, and reconfigured for use by systems and mission analysts. The physical models allow for rational projections of thruster performance based on physical parameters that can be measured in the laboratory. The models and their implications for the design of future MPD thrusters are presented.

MPD Thruster Performance Analytic Models

NASA Technical Reports Server (NTRS)

Gilland, James; Johnston, Geoffrey

2007-01-01

Magnetoplasmadynamic (MPD) thrusters are capable of accelerating quasi-neutral plasmas to high exhaust velocities using Megawatts (MW) of electric power. These characteristics make such devices worthy of consideration for demanding, far-term missions such as the human exploration of Mars or beyond. Assessment of MPD thrusters at the system and mission level is often difficult due to their status as ongoing experimental research topics rather than developed thrusters. However, in order to assess MPD thrusters utility in later missions, some adequate characterization of performance, or more exactly, projected performance, and system level definition are required for use in analyses. The most recent physical models of self-field MPD thrusters have been examined, assessed, and reconfigured for use by systems and mission analysts. The physical models allow for rational projections of thruster performance based on physical parameters that can be measured in the laboratory. The models and their implications for the design of future MPD thrusters are presented.

Management Reviewing Literature: An Evaluation of Selected Characteristics.

ERIC Educational Resources Information Center

Rehman, Sajjad ur

1987-01-01

Reports results of a study which compared the treatment of selected characteristics of the reviewing literature of management in professional and trade journals. The characteristics examined included lag time, review length, descriptive or analytic nature of reviews, positive or negative evaluations, and affiliation of the reviewer. (CLB)

Development of devices for self-injection: using tribological analysis to optimize injection force

PubMed Central

Lange, Jakob; Urbanek, Leos; Burren, Stefan

2016-01-01

This article describes the use of analytical models and physical measurements to characterize and optimize the tribological behavior of pen injectors for self-administration of biopharmaceuticals. One of the main performance attributes of this kind of device is its efficiency in transmitting the external force applied by the user on to the cartridge inside the pen in order to effectuate an injection. This injection force characteristic is heavily influenced by the frictional properties of the polymeric materials employed in the mechanism. Standard friction tests are available for characterizing candidate materials, but they use geometries and conditions far removed from the actual situation inside a pen injector and thus do not always generate relevant data. A new test procedure, allowing the direct measurement of the coefficient of friction between two key parts of a pen injector mechanism using real parts under simulated use conditions, is presented. In addition to the absolute level of friction, the test method provides information on expected evolution of friction over lifetime as well as on expected consistency between individual devices. Paired with an analytical model of the pen mechanism, the frictional data allow the expected overall injection system force efficiency to be estimated. The test method and analytical model are applied to a range of polymer combinations with different kinds of lubrication. It is found that material combinations used without lubrication generally have unsatisfactory performance, that the use of silicone-based internal lubricating additives improves performance, and that the best results can be achieved with external silicone-based lubricants. Polytetrafluoroethylene-based internal lubrication and external lubrication are also evaluated but found to provide only limited benefits unless used in combination with silicone. PMID:27274319

Analytical performance of 17 general chemistry analytes across countries and across manufacturers in the INPUtS project of EQA organizers in Italy, the Netherlands, Portugal, United Kingdom and Spain.

PubMed

Weykamp, Cas; Secchiero, Sandra; Plebani, Mario; Thelen, Marc; Cobbaert, Christa; Thomas, Annette; Jassam, Nuthar; Barth, Julian H; Perich, Carmen; Ricós, Carmen; Faria, Ana Paula

2017-02-01

Optimum patient care in relation to laboratory medicine is achieved when results of laboratory tests are equivalent, irrespective of the analytical platform used or the country where the laboratory is located. Standardization and harmonization minimize differences and the success of efforts to achieve this can be monitored with international category 1 external quality assessment (EQA) programs. An EQA project with commutable samples, targeted with reference measurement procedures (RMPs) was organized by EQA institutes in Italy, the Netherlands, Portugal, UK, and Spain. Results of 17 general chemistry analytes were evaluated across countries and across manufacturers according to performance specifications derived from biological variation (BV). For K, uric acid, glucose, cholesterol and high-density density (HDL) cholesterol, the minimum performance specification was met in all countries and by all manufacturers. For Na, Cl, and Ca, the minimum performance specifications were met by none of the countries and manufacturers. For enzymes, the situation was complicated, as standardization of results of enzymes toward RMPs was still not achieved in 20% of the laboratories and questionable in the remaining 80%. The overall performance of the measurement of 17 general chemistry analytes in European medical laboratories met the minimum performance specifications. In this general picture, there were no significant differences per country and no significant differences per manufacturer. There were major differences between the analytes. There were six analytes for which the minimum quality specifications were not met and manufacturers should improve their performance for these analytes. Standardization of results of enzymes requires ongoing efforts.

Effect of structure and morphology on thermal and electrical properties of polycarbonate film capacitors

NASA Astrophysics Data System (ADS)

Yen, S. P. S.; Lewis, C. R.

Research is reported to identify polycarbonate (PC) film characteristics and fabrication procedures which extend the reliable performance range of PC capacitors to 125 C without derating, and establish quality control techniques and transfer technology to US PC film manufacturers. The approach chosen to solve these problems was to develop techniques for fabricating biaxially oriented (BX) 2 microns or thinner PC film with a low dissipation factor up to 140 C; isotropic dimensional stability; high crystallinity; and high voltage breakdown strength. The PC film structure and morphology was then correlated to thermal and electrical capacitor behavior. Analytical techniques were developed to monitor film quality during capacitor fabrication, and as a result, excellent performance was demonstrated during initial capacitor testing.

Determination of Stable-Unstable Regions of the Slosh Motion in Spinning Space Vehicle by Perturbation Technique

NASA Astrophysics Data System (ADS)

Kang, Jai Young

2005-12-01

The objectives of this study are to perform extensive analysis on internal mass motion for a wider parameter space and to provide suitable design criteria for a broader applicability for the class of spinning space vehicles. In order to examine the stability criterion determined by a perturbation method, some numerical simulations will be performed and compared at various parameter points. In this paper, Ince-Strutt diagram for determination of stable-unstable regions of the internal mass motion of the spinning thrusting space vehicle in terms of design parameters will be obtained by an analytical method. Also, phase trajectories of the motion will be obtained for various parameter values and their characteristics are compared.

Analytical and experimental evaluation of a 3-D hypersonic fixed-geometry, swept, mixed compression inlet

NASA Technical Reports Server (NTRS)

Agnone, Anthony M.

1987-01-01

The performance of a fixed-geometry, swept, mixed compression hypersonic inlet is presented. The experimental evaluation was conducted for a Mach number of 6.0 and for several angles of attack. The measured surface pressures and pitot pressure surveys at the inlet throat are compared to computations using a three-dimensional Euler code and an integral boundary layer theory. Unique features of the intake design, including the boundary layer control, insure a high inlet performance. The experimental data show the inlet has a high mass averaged total pressure recovery, a high mass capture and nearly uniform flow diffusion. The swept inlet exhibits excellent starting characteristics, and high flow stability at angle of attack.

Active Tailoring of Lift Distribution to Enhance Cruise Performance

NASA Technical Reports Server (NTRS)

Flamm, Jeffrey D. (Technical Monitor); Pfeiffer, Neal J.; Christians, Joel G.

2005-01-01

During Phase I of this project, Raytheon Aircraft Company (RAC) has analytically and experimentally evaluated key components of a system that could be implemented for active tailoring of wing lift distribution using low-drag, trailing-edge modifications. Simple systems such as those studied by RAC could be used to enhance the cruise performance of a business jet configuration over a range of typical flight conditions. The trailing-edge modifications focus on simple, deployable mechanisms comprised of extendable small flap panels over portions of the span that could be used to subtly but positively optimize the lift and drag characteristics. The report includes results from low speed wind tunnel testing of the trailing-edge devices, descriptions of potential mechanisms for automation, and an assessment of the technology.

Working towards accreditation by the International Standards Organization 15189 Standard: how to validate an in-house developed method an example of lead determination in whole blood by electrothermal atomic absorption spectrometry.

PubMed

Garcia Hejl, Carine; Ramirez, Jose Manuel; Vest, Philippe; Chianea, Denis; Renard, Christophe

2014-09-01

Laboratories working towards accreditation by the International Standards Organization (ISO) 15189 standard are required to demonstrate the validity of their analytical methods. The different guidelines set by various accreditation organizations make it difficult to provide objective evidence that an in-house method is fit for the intended purpose. Besides, the required performance characteristics tests and acceptance criteria are not always detailed. The laboratory must choose the most suitable validation protocol and set the acceptance criteria. Therefore, we propose a validation protocol to evaluate the performance of an in-house method. As an example, we validated the process for the detection and quantification of lead in whole blood by electrothermal absorption spectrometry. The fundamental parameters tested were, selectivity, calibration model, precision, accuracy (and uncertainty of measurement), contamination, stability of the sample, reference interval, and analytical interference. We have developed a protocol that has been applied successfully to quantify lead in whole blood by electrothermal atomic absorption spectrometry (ETAAS). In particular, our method is selective, linear, accurate, and precise, making it suitable for use in routine diagnostics.

Nonlinear modelling of high-speed catenary based on analytical expressions of cable and truss elements

NASA Astrophysics Data System (ADS)

Song, Yang; Liu, Zhigang; Wang, Hongrui; Lu, Xiaobing; Zhang, Jing

2015-10-01

Due to the intrinsic nonlinear characteristics and complex structure of the high-speed catenary system, a modelling method is proposed based on the analytical expressions of nonlinear cable and truss elements. The calculation procedure for solving the initial equilibrium state is proposed based on the Newton-Raphson iteration method. The deformed configuration of the catenary system as well as the initial length of each wire can be calculated. Its accuracy and validity of computing the initial equilibrium state are verified by comparison with the separate model method, absolute nodal coordinate formulation and other methods in the previous literatures. Then, the proposed model is combined with a lumped pantograph model and a dynamic simulation procedure is proposed. The accuracy is guaranteed by the multiple iterative calculations in each time step. The dynamic performance of the proposed model is validated by comparison with EN 50318, the results of the finite element method software and SIEMENS simulation report, respectively. At last, the influence of the catenary design parameters (such as the reserved sag and pre-tension) on the dynamic performance is preliminarily analysed by using the proposed model.

Complete modeling of rotary ultrasonic motors actuated by traveling flexural waves

NASA Astrophysics Data System (ADS)

Bao, Xiaoqi; Bar-Cohen, Yoseph

2000-06-01

Ultrasonic rotary motors have the potential to meet this NASA need and they are developed as actuators for miniature telerobotic applications. These motors are being adapted for operation at the harsh space environments that include cryogenic temperatures and vacuum and analytical tools for the design of efficient motors are being developed. A hybrid analytical model was developed to address a complete ultrasonic motor as a system. Included in this model is the influence of the rotor dynamics, which was determined experimentally to be important to the motor performance. The analysis employs a 3D finite element model to express the dynamic characteristics of the stator with piezoelectric elements and the rotor. The details of the stator including the teeth, piezoelectric ceramic, geometry, bonding layer, etc. are included to support practical USM designs. A brush model is used for the interface layer and Coulomb's law for the friction between the stator and the rotor. The theoretical predictions were corroborated experimentally for the motor. In parallel, efforts have been made to determine the thermal and vacuum performance of these motors. To explore telerobotic applications for USMs a robotic arm was constructed with such motors.

Analytical study of a quasi-zero stiffness coupling using a torsion magnetic spring with negative stiffness

NASA Astrophysics Data System (ADS)

Zheng, Yisheng; Zhang, Xinong; Luo, Yajun; Zhang, Yahong; Xie, Shilin

2018-02-01

By now, many translation quasi-zero stiffness (QZS) mechanisms have been proposed to overcome the restriction between the isolation frequency range and the load bearing capacity of linear isolators. The couplings of rotor systems undertake the functions of transmitting static driving torque and isolating disturbing torque simultaneously, which creates the demand of torsion QZS mechanisms. Hence a QZS coupling is presented in this paper, where a torsion magnetic spring (TMS) composed of two coaxial ring magnet arrangements in repulsive configuration is employed to produce negative torsion stiffness to counteract the positive stiffness of a rubber spring. In this paper, the expressions of magnetic torque and stiffness are given firstly and verified by finite element simulations; and the effect of geometric parameters of the TMS on its stiffness characteristic is analyzed in detail, which contributes to the optimal design of the TMS. Then dynamic analysis of the QZS coupling is performed and the analytical expression of the torque transmissibility is achieved based on the Harmonic Balance Method. Finally, simulation of the torque transmissibility is carried out to reveal how geometric parameters of the TMS affect the isolation performance.

A Stationary North-Finding Scheme for an Azimuth Rotational IMU Utilizing a Linear State Equality Constraint

PubMed Central

Yu, Huapeng; Zhu, Hai; Gao, Dayuan; Yu, Meng; Wu, Wenqi

2015-01-01

The Kalman filter (KF) has always been used to improve north-finding performance under practical conditions. By analyzing the characteristics of the azimuth rotational inertial measurement unit (ARIMU) on a stationary base, a linear state equality constraint for the conventional KF used in the fine north-finding filtering phase is derived. Then, a constrained KF using the state equality constraint is proposed and studied in depth. Estimation behaviors of the concerned navigation errors when implementing the conventional KF scheme and the constrained KF scheme during stationary north-finding are investigated analytically by the stochastic observability approach, which can provide explicit formulations of the navigation errors with influencing variables. Finally, multiple practical experimental tests at a fixed position are done on a postulate system to compare the stationary north-finding performance of the two filtering schemes. In conclusion, this study has successfully extended the utilization of the stochastic observability approach for analytic descriptions of estimation behaviors of the concerned navigation errors, and the constrained KF scheme has demonstrated its superiority over the conventional KF scheme for ARIMU stationary north-finding both theoretically and practically. PMID:25688588

Development of Processing Techniques for Advanced Thermal Protection Materials

NASA Technical Reports Server (NTRS)

Selvaduray, Guna; Cox, Michael; Srinivasan, Vijayakumar

1997-01-01

Thermal Protection Materials Branch (TPMB) has been involved in various research programs to improve the properties and structural integrity of the existing aerospace high temperature materials. Specimens from various research programs were brought into the analytical laboratory for the purpose of obtaining and refining the material characterization. The analytical laboratory in TPMB has many different instruments which were utilized to determine the physical and chemical characteristics of materials. Some of the instruments that were utilized by the SJSU students are: Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX), X-ray Diffraction Spectrometer (XRD), Fourier Transform-Infrared Spectroscopy (FTIR), Ultra Violet Spectroscopy/Visible Spectroscopy (UV/VIS), Particle Size Analyzer (PSA), and Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES). The above mentioned analytical instruments were utilized in the material characterization process of the specimens from research programs such as: aerogel ceramics (I) and (II), X-33 Blankets, ARC-Jet specimens, QUICFIX specimens and gas permeability of lightweight ceramic ablators. In addition to analytical instruments in the analytical laboratory at TPMB, there are several on-going experiments. One particular experiment allows the measurement of permeability of ceramic ablators. From these measurements, physical characteristics of the ceramic ablators can be derived.

A field study of selected U.S. Geological Survey analytical methods for measuring pesticides in filtered stream water, June - September 2012

USGS Publications Warehouse

Martin, Jeffrey D.; Norman, Julia E.; Sandstrom, Mark W.; Rose, Claire E.

2017-09-06

U.S. Geological Survey monitoring programs extensively used two analytical methods, gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry, to measure pesticides in filtered water samples during 1992–2012. In October 2012, the monitoring programs began using direct aqueous-injection liquid chromatography tandem mass spectrometry as a new analytical method for pesticides. The change in analytical methods, however, has the potential to inadvertently introduce bias in analysis of datasets that span the change.A field study was designed to document performance of the new method in a variety of stream-water matrices and to quantify any potential changes in measurement bias or variability that could be attributed to changes in analytical methods. The goals of the field study were to (1) summarize performance (bias and variability of pesticide recovery) of the new method in a variety of stream-water matrices; (2) compare performance of the new method in laboratory blank water (laboratory reagent spikes) to that in a variety of stream-water matrices; (3) compare performance (analytical recovery) of the new method to that of the old methods in a variety of stream-water matrices; (4) compare pesticide detections and concentrations measured by the new method to those of the old methods in a variety of stream-water matrices; (5) compare contamination measured by field blank water samples in old and new methods; (6) summarize the variability of pesticide detections and concentrations measured by the new method in field duplicate water samples; and (7) identify matrix characteristics of environmental water samples that adversely influence the performance of the new method. Stream-water samples and a variety of field quality-control samples were collected at 48 sites in the U.S. Geological Survey monitoring networks during June–September 2012. Stream sites were located across the United States and included sites in agricultural and urban land-use settings, as well as sites on major rivers.The results of the field study identified several challenges for the analysis and interpretation of data analyzed by both old and new methods, particularly when data span the change in methods and are combined for analysis of temporal trends in water quality. The main challenges identified are large (greater than 30 percent), statistically significant differences in analytical recovery, detection capability, and (or) measured concentrations for selected pesticides. These challenges are documented and discussed, but specific guidance or statistical methods to resolve these differences in methods are beyond the scope of the report. The results of the field study indicate that the implications of the change in analytical methods must be assessed individually for each pesticide and method.Understanding the possible causes of the systematic differences in concentrations between methods that remain after recovery adjustment might be necessary to determine how to account for the differences in data analysis. Because recoveries for each method are independently determined from separate reference standards and spiking solutions, the differences might be due to an error in one of the reference standards or solutions or some other basic aspect of standard procedure in the analytical process. Further investigation of the possible causes is needed, which will lead to specific decisions on how to compensate for these differences in concentrations in data analysis. In the event that further investigations do not provide insight into the causes of systematic differences in concentrations between methods, the authors recommend continuing to collect and analyze paired environmental water samples by both old and new methods. This effort should be targeted to seasons, sites, and expected concentrations to supplement those concentrations already assessed and to compare the ongoing analytical recovery of old and new methods to those observed in the summer and fall of 2012.

Combined Effect of Contraction Ratio and Chamber Pressure on the Performance of a Gaseous Hydrogen-Liquid-Oxygen Combustor for a Given Propellant Weight Flow and Oxidant-Fuel Ratio

NASA Technical Reports Server (NTRS)

Hersch, Martin

1961-01-01

The effect of contraction ratio and chamber pressure on the combustion performance of a gaseous-hydrogen-liquid-oxygen combustor was investigated analytically and experimentally. The experiment was conducted with a "two-dimensional" gaseous-hydrogen-liquid-oxygen engine of about 150-pound thrust. The contraction ratio was varied from 1.5 to 6 by changing the nozzle throat area. This variation resulted in a chamber pressure variation of about 25 to 120 pounds per square inch. The experimental results were corrected for heat transfer to the engine walls and momentum pressure losses. The experimental performance, as evaluated in terms of characteristic exhaust velocity, was 98 percent of theoretical at contraction ratios greater than 3 but decreased very rapidly at smaller contraction ratios. The heat-transfer rate increased with increasing contraction ratio and chamber pressure; it was about 1 Btu per square inch per second at a contraction ratio of 1.5 and increased to about 3 at a contraction ratio of 6. The combined effects of contraction-ratio and chamber-pressure changes on performance were investigated analytically with a mixing model and a vaporization model. The mixing model predicted very poor mixing at contraction ratios below 3 and almost perfect mixing at higher contraction ratios. The performance predicted by the vaporization model was very close to 100 percent for all contraction ratios. From these results, it was concluded that the performance was limited by poor mixing at low contraction ratios and chamber pressures.

CNV-ROC: A cost effective, computer-aided analytical performance evaluator of chromosomal microarrays

PubMed Central

Goodman, Corey W.; Major, Heather J.; Walls, William D.; Sheffield, Val C.; Casavant, Thomas L.; Darbro, Benjamin W.

2016-01-01

Chromosomal microarrays (CMAs) are routinely used in both research and clinical laboratories; yet, little attention has been given to the estimation of genome-wide true and false negatives during the assessment of these assays and how such information could be used to calibrate various algorithmic metrics to improve performance. Low-throughput, locus-specific methods such as fluorescence in situ hybridization (FISH), quantitative PCR (qPCR), or multiplex ligation-dependent probe amplification (MLPA) preclude rigorous calibration of various metrics used by copy number variant (CNV) detection algorithms. To aid this task, we have established a comparative methodology, CNV-ROC, which is capable of performing a high throughput, low cost, analysis of CMAs that takes into consideration genome-wide true and false negatives. CNV-ROC uses a higher resolution microarray to confirm calls from a lower resolution microarray and provides for a true measure of genome-wide performance metrics at the resolution offered by microarray testing. CNV-ROC also provides for a very precise comparison of CNV calls between two microarray platforms without the need to establish an arbitrary degree of overlap. Comparison of CNVs across microarrays is done on a per-probe basis and receiver operator characteristic (ROC) analysis is used to calibrate algorithmic metrics, such as log2 ratio threshold, to enhance CNV calling performance. CNV-ROC addresses a critical and consistently overlooked aspect of analytical assessments of genome-wide techniques like CMAs which is the measurement and use of genome-wide true and false negative data for the calculation of performance metrics and comparison of CNV profiles between different microarray experiments. PMID:25595567

Study on internal flow and surface deformation of large droplet levitated by ultrasonic wave.

PubMed

Abe, Yutaka; Hyuga, Daisuke; Yamada, Shogo; Aoki, Kazuyoshi

2006-09-01

It is expected that new materials will be manufactured with containerless processing under the microgravity environment in space. Under the microgravity environment, handling technology of molten metal is important for such processes. There are a lot of previous studies about droplet levitation technologies, including the use of acoustic waves, as the holding technology. However, experimental and analytical information about the relationship between surface deformation and internal flow of a large levitated droplet is still unknown. The purpose of this study is to experimentally investigate the large droplet behavior levitated by the acoustic wave field and its internal flow. To achieve this, first, numerical simulation is conducted to clarify the characteristics of acoustic wave field. Second, the levitation characteristic and the internal flow of the levitated droplet are investigated by the ultrasonic standing wave under normal gravity environment. Finally, the levitation characteristic and internal flow of levitated droplet are observed under microgravity in an aircraft to compare results with the experiment performed under the normal gravity environment.

Hardwall acoustical characteristics and measurement capabilities of the NASA Lewis 9 x 15 foot low speed wind tunnel

NASA Technical Reports Server (NTRS)

Rentz, P. E.

1976-01-01

Experimental evaluations of the acoustical characteristics and source sound power and directionality measurement capabilities of the NASA Lewis 9 x 15 foot low speed wind tunnel in the untreated or hardwall configuration were performed. The results indicate that source sound power estimates can be made using only settling chamber sound pressure measurements. The accuracy of these estimates, expressed as one standard deviation, can be improved from + or - 4 db to + or - 1 db if sound pressure measurements in the preparation room and diffuser are also used and source directivity information is utilized. A simple procedure is presented. Acceptably accurate measurements of source direct field acoustic radiation were found to be limited by the test section reverberant characteristics to 3.0 feet for omni-directional and highly directional sources. Wind-on noise measurements in the test section, settling chamber and preparation room were found to depend on the sixth power of tunnel velocity. The levels were compared with various analytic models. Results are presented and discussed.

Study on characteristics of the aperture-averaging factor of atmospheric scintillation in terrestrial optical wireless communication

NASA Astrophysics Data System (ADS)

Shen, Hong; Liu, Wen-xing; Zhou, Xue-yun; Zhou, Li-ling; Yu, Long-Kun

2018-02-01

In order to thoroughly understand the characteristics of the aperture-averaging effect of atmospheric scintillation in terrestrial optical wireless communication and provide references for engineering design and performance evaluation of the optics system employed in the atmosphere, we have theoretically deduced the generally analytic expression of the aperture-averaging factor of atmospheric scintillation, and numerically investigated characteristics of the apertureaveraging factor under different propagation conditions. The limitations of the current commonly used approximate calculation formula of aperture-averaging factor have been discussed, and the results showed that the current calculation formula is not applicable for the small receiving aperture under non-uniform turbulence link. Numerical calculation has showed that aperture-averaging factor of atmospheric scintillation presented an exponential decline model for the small receiving aperture under non-uniform turbulent link, and the general expression of the model was given. This model has certain guiding significance for evaluating the aperture-averaging effect in the terrestrial optical wireless communication.

Flight Test of GL-1 Glider Half Scale Prototype

NASA Astrophysics Data System (ADS)

Fikri Zulkarnain, Muhammad; Fazlur Rahman, Muhammad; Luthfi Imam Nurhakim, Muhammad; Arifianto, Ony; Mulyanto, Taufiq

2018-04-01

GL-1 is a single-seat mid-performance glider, designed to be Indonesian National Glider. The Glider have been developing since 2014. The development produced a half scale prototype called BL-1, which had accomplished static test in 2016, then followed by first flight test at April 20th 2017, and second flight test at May 21st 2017. The purpose of the flight test was to obtain familiarization of the aircraft, aerodynamics characteristics and flow visualization, with data from flight recorded in FDR. The flight test resulted in two flights with total length of 21 minutes. The data from FDR and flight test documents extracted to analyze the characteristics and behavior of the aircraft during flight test. The aerodynamics characteristic was close to analytical results. The control was good; however, the effectiveness of control surface may need to be further analyzed. The result of the flight test will be used as a reference for further improvements and may need further testing.

European Multicenter Study on Analytical Performance of DxN Veris System HCV Assay.

PubMed

Braun, Patrick; Delgado, Rafael; Drago, Monica; Fanti, Diana; Fleury, Hervé; Gismondo, Maria Rita; Hofmann, Jörg; Izopet, Jacques; Kühn, Sebastian; Lombardi, Alessandra; Marcos, Maria Angeles; Sauné, Karine; O'Shea, Siobhan; Pérez-Rivilla, Alfredo; Ramble, John; Trimoulet, Pascale; Vila, Jordi; Whittaker, Duncan; Artus, Alain; Rhodes, Daniel W

2017-04-01

The analytical performance of the Veris HCV Assay for use on the new and fully automated Beckman Coulter DxN Veris Molecular Diagnostics System (DxN Veris System) was evaluated at 10 European virology laboratories. Precision, analytical sensitivity, specificity, and performance with negative samples, linearity, and performance with hepatitis C virus (HCV) genotypes were evaluated. Precision for all sites showed a standard deviation (SD) of 0.22 log 10 IU/ml or lower for each level tested. Analytical sensitivity determined by probit analysis was between 6.2 and 9.0 IU/ml. Specificity on 94 unique patient samples was 100%, and performance with 1,089 negative samples demonstrated 100% not-detected results. Linearity using patient samples was shown from 1.34 to 6.94 log 10 IU/ml. The assay demonstrated linearity upon dilution with all HCV genotypes. The Veris HCV Assay demonstrated an analytical performance comparable to that of currently marketed HCV assays when tested across multiple European sites. Copyright © 2017 American Society for Microbiology.

Build-Up Approach to Updating the Mock Quiet Spike Beam Model

NASA Technical Reports Server (NTRS)

Herrera, Claudia Y.; Pak, Chan-gi

2007-01-01

When a new aircraft is designed or a modification is done to an existing aircraft, the aeroelastic properties of the aircraft should be examined to ensure the aircraft is flight worthy. Evaluating the aeroelastic properties of a new or modified aircraft can include performing a variety of analyses, such as modal and flutter analyses. In order to produce accurate results from these analyses, it is imperative to work with finite element models (FEM) that have been validated by or correlated to ground vibration test (GVT) data, Updating an analytical model using measured data is a challenge in the area of structural dynamics. The analytical model update process encompasses a series of optimizations that match analytical frequencies and mode shapes to the measured modal characteristics of structure. In the past, the method used to update a model to test data was "trial and error." This is an inefficient method - running a modal analysis, comparing the analytical results to the GVT data, manually modifying one or more structural parameters (mass, CG, inertia, area, etc.), rerunning the analysis, and comparing the new analytical modal characteristics to the GVT modal data. If the match is close enough (close enough defined by analyst's updating requirements), then the updating process is completed. If the match does not meet updating-requirements, then the parameters are changed again and the process is repeated. Clearly, this manual optimization process is highly inefficient for large FEM's and/or a large number of structural parameters. NASA Dryden Flight Research Center (DFRC) has developed, in-house, a Mode Matching Code that automates the above-mentioned optimization process, DFRC's in-house Mode Matching Code reads mode shapes and frequencies acquired from GVT to create the target model. It also reads the current analytical model, as we11 as the design variables and their upper and lower limits. It performs a modal analysis on this model and modifies it to create an updated model that has similar mode shapes and frequencies as those of the target model. The Mode Matching Code output frequencies and modal assurance criteria (MAC) values that allow for the quantified comparison of the updated model versus the target model. A recent application of this code is the F453 supersonic flight testing platform, NASA DFRC possesses a modified F-15B that is used as a test bed aircraft for supersonic flight experiments. Traditionally, the finite element model of the test article is generated. A GVT is done on the test article ta validate and update its FEM. This FEM is then mated to the F-15B model, which was correlated to GVT data in fall of 2004, A GVT is conducted with the test article mated to the aircraft, and this mated F-15B/ test article FEM is correlated to this final GVT.

Median of patient results as a tool for assessment of analytical stability.

PubMed

Jørgensen, Lars Mønster; Hansen, Steen Ingemann; Petersen, Per Hyltoft; Sölétormos, György

2015-06-15

In spite of the well-established external quality assessment and proficiency testing surveys of analytical quality performance in laboratory medicine, a simple tool to monitor the long-term analytical stability as a supplement to the internal control procedures is often needed. Patient data from daily internal control schemes was used for monthly appraisal of the analytical stability. This was accomplished by using the monthly medians of patient results to disclose deviations from analytical stability, and by comparing divergences with the quality specifications for allowable analytical bias based on biological variation. Seventy five percent of the twenty analytes achieved on two COBASs INTEGRA 800 instruments performed in accordance with the optimum and with the desirable specifications for bias. Patient results applied in analytical quality performance control procedures are the most reliable sources of material as they represent the genuine substance of the measurements and therefore circumvent the problems associated with non-commutable materials in external assessment. Patient medians in the monthly monitoring of analytical stability in laboratory medicine are an inexpensive, simple and reliable tool to monitor the steadiness of the analytical practice. Copyright © 2015 Elsevier B.V. All rights reserved.

The dynamic interaction of a marine hydrokinetic turbine with its environment

NASA Astrophysics Data System (ADS)

Kolekar, Nitin; Banerjee, Arindam

2014-11-01

Unlike wind turbines, marine hydrokinetic and tidal turbines operate in a bounded flow environment where flow is constrained between deformable free surface and fixed river/sea bed. The proximity to free surface modifies the wake dynamics behind the turbine. Further, size & shape of this wake is not constant but depends on multiple factors like flow speed, turbine blade geometry, and rotational speed. In addition, the turbulence characteristics of incoming flow also affects the flow field and hence the performance. The current work aims at understanding the dynamic interaction of a hydrokinetic turbine (HkT) with free surface and flow turbulence through experimental investigations. Results will be presented from experimental study carried out in an open channel test facility at Lehigh University with a three bladed, constant chord, zero twist HkT under various operating conditions. Froude number (ratio of characteristic flow velocity to gravitational wave velocity) is used to characterize the effect of free surface proximity on turbine performance. Experimental results will be compared with analytical models based on blade element momentum theory. Characterization of wake meandering and flow around turbine will be performed using a stereo-Particle Image Velocimetry technique.

Trapped Field Characteristics of Stacked YBCO Thin Plates for Compact NMR Magnets: Spatial Field Distribution and Temporal Stability

PubMed Central

Hahn, Seungyong; Kim, Seok Beom; Ahn, Min Cheol; Voccio, John; Bascuñán, Juan; Iwasa, Yukikazu

2010-01-01

This paper presents experimental and analytical results of trapped field characteristics of a stack of square YBCO thin film plates for compact NMR magnets. Each YBCO plate, 40 mm × 40 mm × 0.08 mm, has a 25-mm diameter hole at its center. A total of 500 stacked plates were used to build a 40-mm long magnet. Its trapped field, in a bath of liquid nitrogen, was measured for spatial field distribution and temporal stability. Comparison of measured and analytical results is presented: the effects on trapped field characteristics of the unsaturated nickel substrate and the non-uniform current distribution in the YBCO plate are discussed. PMID:20585463

Dynamics of epidemic spreading model with drug-resistant variation on scale-free networks

NASA Astrophysics Data System (ADS)

Wan, Chen; Li, Tao; Zhang, Wu; Dong, Jing

2018-03-01

Considering the influence of the virus' drug-resistant variation, a novel SIVRS (susceptible-infected-variant-recovered-susceptible) epidemic spreading model with variation characteristic on scale-free networks is proposed in this paper. By using the mean-field theory, the spreading dynamics of the model is analyzed in detail. Then, the basic reproductive number R0 and equilibriums are derived. Studies show that the existence of disease-free equilibrium is determined by the basic reproductive number R0. The relationships between the basic reproductive number R0, the variation characteristic and the topology of the underlying networks are studied in detail. Furthermore, our studies prove the global stability of the disease-free equilibrium, the permanence of epidemic and the global attractivity of endemic equilibrium. Numerical simulations are performed to confirm the analytical results.

Man-Vehicle Systems Research Facility - Design and operating characteristics

NASA Technical Reports Server (NTRS)

Shiner, Robert J.; Sullivan, Barry T.

1992-01-01

This paper describes the full-mission flight simulation facility at the NASA Ames Research Center. The Man-Vehicle Systems Research Facility (MVSRF) supports aeronautical human factors research and consists of two full-mission flight simulators and an air-traffic-control simulator. The facility is used for a broad range of human factors research in both conventional and advanced aviation systems. The objectives of the research are to improve the understanding of the causes and effects of human errors in aviation operations, and to limit their occurrence. The facility is used to: (1) develop fundamental analytical expressions of the functional performance characteristics of aircraft flight crews; (2) formulate principles and design criteria for aviation environments; (3) evaluate the integration of subsystems in contemporary flight and air traffic control scenarios; and (4) develop training and simulation technologies.

Unsteady aerodynamic analysis of space shuttle vehicles. Part 2: Steady and unsteady aerodynamics of sharp-edged delta wings

NASA Technical Reports Server (NTRS)

Ericsson, L. E.; Reding, J. P.

1973-01-01

An analysis of the steady and unsteady aerodynamics of sharp-edged slender wings has been performed. The results show that slender wing theory can be modified to give the potential flow static and dynamic characteristics in incompressible flow. A semiempirical approximation is developed for the vortex-induced loads, and it is shown that the analytic approximation for sharp-edged slender wings gives good prediction of experimentally determined steady and unsteady aerodynamics at M = 0 and M = 1. The predictions are good not only for delta wings but also for so-called arrow and diamond wings. The results indicate that the effects of delta planform lifting surfaces can be included in a simple manner when determining elastic launch vehicle dynamic characteristics. For Part 1 see (N73-32763).

Chemical Functionalization of Graphene Family Members

NASA Astrophysics Data System (ADS)

Vacchi, Isabella Anna; Ménard-Moyon, Cécilia; Bianco, Alberto

2017-01-01

Thanks to their outstanding physicochemical properties, graphene and its derivatives are interesting nanomaterials with a high potential in several fields. Graphene, graphene oxide, and reduced graphene oxide, however, differ partially in their characteristics due to their diverse surface composition. Those differences influence the chemical reactivity of these materials. In the following chapter the reactivity and main functionalization reactions performed on graphene, graphene oxide, and reduced graphene oxide are discussed. A part is also dedicated to the main analytical techniques used for characterization of these materials. Functionalization of graphene and its derivatives is highly important to modulate their characteristics and design graphene-based conjugates with novel properties. Functionalization can be covalent by forming strong and stable bonds with the graphene surface, or non-covalent via π-π, electrostatic, hydrophobic, and/or van der Waals interactions. Both types of functionalization are currently exploited.

The Unanticipated Explosion: Private Higher Education's Global Surge

ERIC Educational Resources Information Center

Levy, Daniel C.

2006-01-01

This article provides a broad and analytical overview of the private higher education explosion. It concentrates on a crucial yet generally ignored characteristic: the largely unanticipated emergence, not following a broad preconception or systemic design. The article's main conceptual thrust is to identify and provide analytical perspectives on…

JPRS Report, Science & Technology, USSR: Engineering & Equipment

DTIC Science & Technology

1987-08-05

working successfully in the " Veda " PO and at the analytical instruments plant. Characteristically, it was these very enterprises which were on top in...the 1985 review: the analytical instruments plant collective came in first, the " Veda " PO collective came in second, and the "Elektronmash" PO

On justification of efficient Energy-Force parameters of Hydraulic-excavator main mechanisms

NASA Astrophysics Data System (ADS)

Komissarov, Anatoliy; Lagunova, Yuliya; Shestakov, Viktor; Lukashuk, Olga

2018-03-01

The article formulates requirements for energy-efficient designs of the operational equipment of a hydraulic excavator (its boom, stick and bucket) and defines, for a mechanism of that equipment, a new term “performance characteristic”. The drives of main rotation mechanisms of the equipment are realized by hydraulic actuators (hydraulic cylinders) and transmission (leverage) mechanisms, with the actuators (the cylinders themselves, their pistons and piston rods) also acting as links of the leverage. Those drives are characterized by the complexity of translating mechanical-energy parameters of the actuators into energy parameters of the driven links (a boom, a stick and a bucket). Relations between those parameters depend as much on the types of mechanical characteristics of the hydraulic actuators as on the types of structural schematics of the transmission mechanisms. To assess how energy-force parameters of the driven links change when a typical operation is performed, it was proposed to calculate performance characteristics of the main mechanisms as represented by a set of values of transfer functions, i.e. by functional dependences between driven links and driving links (actuators). Another term “ideal performance characteristic” of a mechanism was introduced. Based on operation-emulating models for the main mechanisms of hydraulic excavators, analytical expressions were derived to calculate kinematic and force transfer functions of the main mechanisms.

Receiver operating characteristic analysis of age-related changes in lineup performance.

PubMed

Humphries, Joyce E; Flowe, Heather D

2015-04-01

In the basic face memory literature, support has been found for the late maturation hypothesis, which holds that face recognition ability is not fully developed until at least adolescence. Support for the late maturation hypothesis in the criminal lineup identification literature, however, has been equivocal because of the analytic approach that has been used to examine age-related changes in identification performance. Recently, receiver operator characteristic (ROC) analysis was applied for the first time in the adult eyewitness memory literature to examine whether memory sensitivity differs across different types of lineup tests. ROC analysis allows for the separation of memory sensitivity from response bias in the analysis of recognition data. Here, we have made the first ROC-based comparison of adults' and children's (5- and 6-year-olds and 9- and 10-year-olds) memory performance on lineups by reanalyzing data from Humphries, Holliday, and Flowe (2012). In line with the late maturation hypothesis, memory sensitivity was significantly greater for adults compared with young children. Memory sensitivity for older children was similar to that for adults. The results indicate that the late maturation hypothesis can be generalized to account for age-related performance differences on an eyewitness memory task. The implications for developmental eyewitness memory research are discussed. Copyright © 2014 Elsevier Inc. All rights reserved.

Development of monofilar rotor hub vibration absorber

NASA Technical Reports Server (NTRS)

Duh, J.; Miao, W.

1983-01-01

A design and ground test program was conducted to study the performance of the monofilar absorber for vibration reduction on a four-bladed helicopter. A monofilar is a centrifugal tuned two degree-of-freedom rotor hub absorber that provides force attenuation at two frequencies using the same dynamic mass. Linear and non-linear analyses of the coupled monofilar/airframe system were developed to study tuning and attenuation characteristics. Based on the analysis, a design was fabricated and impact bench tests verified the calculated non-rotating natural frequencies and mode shapes. Performance characteristics were measured using a rotating absorber test facility. These tests showed significant attenuation of fixed-system 4P hub motions due to 3P inplane rotating-system hub forces. In addition, detuning effects of the 3P monofilar modal response were small due to the nonlinearities and tuning pin slippage. However, attenuation of 4P hub motions due to 5P inplane hub forces was poor. The performance of the 5P monofilar modal response was degraded by torsional motion of the dynamic mass relative to the support arm which resulted in binding of the dynamic components. Analytical design studies were performed to evaluate this torsional motion problem. An alternative design is proposed which may alleviate the torsional motion of the dynamic mass.

Analytical study of the reflection and transmission coefficient of the submarine interface

NASA Astrophysics Data System (ADS)

Zhang, Guangli; Hao, Chongtao; Yao, Chen

2018-05-01

The analytical study of the reflection and transmission coefficient of the seafloor interface is essential for the characterization of the ocean bottom in marine seismic exploration. Based on the boundary conditions of the seafloor interface, the analytical expression of the reflection and transmission coefficient at the submarine interface is derived in this study by using the steady-state wave solution of the elastic wave in a homogeneous, isotropic medium. With this analytical expression, the characteristics of the reflection and transmission coefficient at the submarine interface are analysed and discussed using critical angles. The results show that the change in the reflection and transmission coefficient with the incidence angle presents a "segmented" characteristic, in which the critical angle is the dividing point. The amplitude value and phase angle of the coefficient at the submarine interface change dramatically at the critical angle, which is related to the P- and S-wave velocities in the seabed layer. Compared with the stiff seabed, the soft seabed has a larger P-wave critical angle and an absence of the converted S-wave critical angle, owing to the low P- and S-wave velocities in the solid seabed layer. By analysing and discussing the special changes that occur in the coefficient values at the critical angle, the reflection and transmission characteristics of the different incident angles are obtained. Synthetic models of both stiff and soft seafloors are provided in this study to verify the analytical results. Finally, we compared our synthetic results with real data from the Gulf of Mexico, which enabled the validation of our conclusions.

Caustic Singularities Of High-Gain, Dual-Shaped Reflectors

NASA Technical Reports Server (NTRS)

Galindo, Victor; Veruttipong, Thavath W.; Imbriale, William A.; Rengarajan, Sambiam

1991-01-01

Report presents study of some sources of error in analysis, by geometric theory of diffraction (GTD), of performance of high-gain, dual-shaped antenna reflector. Study probes into underlying analytic causes of singularity, with view toward devising and testing practical methods to avoid problems caused by singularity. Hybrid physical optics (PO) approach used to study near-field spillover or noise-temperature characteristics of high-gain relector antenna efficiently and accurately. Report illustrates this approach and underlying principles by presenting numerical results, for both offset and symmetrical reflector systems, computed by GTD, PO, and PO/GO methods.

Heat and momentum transfer model studies applicable to once-through, forced convection potassium boiling

NASA Technical Reports Server (NTRS)

Sabin, C. M.; Poppendiek, H. F.

1971-01-01

A number of heat transfer and fluid flow mechanisms that control once-through, forced convection potassium boiling are studied analytically. The topics discussed are: (1) flow through tubes containing helical wire inserts, (2) motion of droplets entrained in vapor flow, (3) liquid phase distribution in boilers, (4) temperature distributions in boiler tube walls, (5) mechanisms of heat transfer regime change, and (6) heat transfer in boiler tubes. Whenever possible, comparisons of predicted and actual performances are made. The model work presented aids in the prediction of operating characteristics of actual boilers.

Preliminary Design of a SP-100/Stirling Radiatively Coupled Heat Exchanger

NASA Technical Reports Server (NTRS)

Schmitz, Paul; Tower, Leonard; Dawson, Ronald; Blue, Brian; Dunn, Pat

1995-01-01

Several methods for coupling the SP-100 space nuclear reactor to the NASA Lewis Research Center's Free Piston Stirling Power Convertor (FPSPC) are presented. A 25 kWe, dual opposed Stirling convertor configuration is used in these designs. The concepts use radiative coupling between the SP-100 lithium loop and the sodium heat pipe of the Stirling convertor to transfer the heat from the reactor to the convertor. Four separate configurations are presented. Masses for the four designs vary from 41 to 176 kgs. Each design's structure, heat transfer characteristics, and heat pipe performance are analytically modeled.

Data Wrangling Within Different Astronomy Career Trajectories

NASA Astrophysics Data System (ADS)

Guillen, Reynal; Gu, D.; Holbrook, J.; Murillo, L.; Traweek, S.

2012-01-01

Five kinds of astronomers work with large data sets: cosmologists, data analysts, instrumentation people, observers, and numerical theorists. Each of these career trajectories can diverge and converge in and out of collaborations with each other and perform different kinds of work. Nonetheless, each group defines and wrangles data differently. This poster characterizes their different meanings of data, analytic skills, techniques, and technologies. It also identifies some sites and patterns of convergence. We plot these collaborative relationships in bi-partite graphs. These emergent characteristics of the astronomy workforce have implications for curricula, pedagogies, and the division of labor in research collaborations.

Preliminary design of a SP-100/Stirling radiatively coupled heat exchanger

NASA Astrophysics Data System (ADS)

Schmitz, Paul; Tower, Leonard; Dawson, Ronald; Blue, Brian; Dunn, Pat

1995-10-01

Several methods for coupling the SP-100 space nuclear reactor to the NASA Lewis Research Center's Free Piston Stirling Power Convertor (FPSPC) are presented. A 25 kWe, dual opposed Stirling convertor configuration is used in these designs. The concepts use radiative coupling between the SP-100 lithium loop and the sodium heat pipe of the Stirling convertor to transfer the heat from the reactor to the convertor. Four separate configurations are presented. Masses for the four designs vary from 41 to 176 kgs. Each design's structure, heat transfer characteristics, and heat pipe performance are analytically modeled.

Immobilized lipid-bilayer materials

DOEpatents

Sasaki, Darryl Y.; Loy, Douglas A.; Yamanaka, Stacey A.

2000-01-01

A method for preparing encapsulated lipid-bilayer materials in a silica matrix comprising preparing a silica sol, mixing a lipid-bilayer material in the silica sol and allowing the mixture to gel to form the encapsulated lipid-bilayer material. The mild processing conditions allow quantitative entrapment of pre-formed lipid-bilayer materials without modification to the material's spectral characteristics. The method allows for the immobilization of lipid membranes to surfaces. The encapsulated lipid-bilayer materials perform as sensitive optical sensors for the detection of analytes such as heavy metal ions and can be used as drug delivery systems and as separation devices.

Analytical transient analysis of Peltier device for laser thermal tuning

NASA Astrophysics Data System (ADS)

Sheikhnejad, Yahya; Vujicic, Zoran; Almeida, Álvaro J.; Bastos, Ricardo; Shahpari, Ali; Teixeira, António L.

2017-08-01

Recently, industrial trends strongly favor the concepts of high density, low power consumption and low cost applications of Datacom and Telecom pluggable transceiver modules. Hence, thermal management plays an important role, especially in the design of high-performance compact optical transceivers. Extensive care should be taken on wavelength drift for thermal tuning lasers using thermoelectric cooler and indeed, accurate expression is needed to describe transient characteristics of the Peltier device to achieve maximum controllability. In this study, the exact solution of governing equation is presented, considering Joule heating, heat conduction, heat flux of laser diode and thermoelectric effect in one dimension.

Analytical solutions to the free vibration of a double-walled carbon nanotube carrying a bacterium at its tip

NASA Astrophysics Data System (ADS)

Storch, Joel A.; Elishakoff, Isaac

2013-11-01

We calculate the natural frequencies and mode shapes of a cantilevered double-walled carbon nanotube carrying a rigid body—representative of a bacterium or virus—at the tip of the outer nanotube. By idealizing the nanotubes as Bernoulli-Euler beams, we are able to obtain exact expressions for both the mode shapes and characteristic frequency equation. Separate analyses are performed for the special case of a concentrated tip mass and the more complicated situation where the tip body also exhibits inertia and mass center offset from the beam tip.

Gas chromatography coupled to tunable pulsed glow discharge time-of-flight mass spectrometry for environmental analysis.

PubMed

Solà-Vázquez, Auristela; Lara-Gonzalo, Azucena; Costa-Fernández, José M; Pereiro, Rosario; Sanz-Medel, Alfredo

2010-05-01

A tuneable microsecond pulsed direct current glow discharge (GD)-time-of-flight mass spectrometer MS(TOF) developed in our laboratory was coupled to a gas chromatograph (GC) to obtain sequential collection of the mass spectra, at different temporal regimes occurring in the GD pulses, during elution of the analytes. The capabilities of this set-up were explored using a mixture of volatile organic compounds of environmental concern: BrClCH, Cl(3)CH, Cl(4)C, BrCl(2)CH, Br(2)ClCH, Br(3)CH. The experimental parameters of the GC-pulsed GD-MS(TOF) prototype were optimized in order to separate appropriately and analyze the six selected organic compounds, and two GC carrier gases, helium and nitrogen, were evaluated. Mass spectra for all analytes were obtained in the prepeak, plateau and afterpeak temporal regimes of the pulsed GD. Results showed that helium offered the best elemental sensitivity, while nitrogen provided higher signal intensities for fragments and molecular peaks. The analytical performance characteristics were also worked out for each analyte. Absolute detection limits obtained were in the order of ng. In a second step, headspace solid phase microextraction (HS SPME), as sample preparation and preconcentration technique, was evaluated for the quantification of the compounds under study, in order to achieve the required analytical sensitivity for trihalomethanes European Union (EU) environmental legislation. The analytical figures of merit obtained using the proposed methodology showed rather good detection limits (between 2 and 13 microg L(-1) depending on the analyte). In fact, the developed methodology met the EU legislation requirements (the maximum level permitted in tap water for the "total trihalomethanes" is set at 100 microg L(-1)). Real analysis of drinking water and river water were successfully carried out. To our knowledge this is the first application of GC-pulsed GD-MS(TOF) for the analysis of real samples. Its ability to provide elemental, fragments and molecular information of the organic compounds is demonstrated.

Development of an analytical method to predict helicopter main rotor performance in icing conditions

NASA Technical Reports Server (NTRS)

Britton, Randall K.

1992-01-01

Historically, certification of a helicopter for flight into known icing conditions was a problem. This is because of the current emphasis on flight testing for verification of system performance. Flight testing in icing conditions is difficult because, in addition to being dangerous and expensive, many times conditions which are sought after cannot be readily found in nature. The problem is compounded for helicopters because of their small range in comparison to many fixed wing aircraft. Thus, helicopters are forced to wait for conditions to occur in a certain region rather than seeking them out. These and other drawbacks to flight testing prompted extreme interest in developing validated alternatives to flight testing. One such alternative is theoretical prediction. It is desirable to have the ability to predict how a helicopter will perform when subjected to icing conditions. Herein, calculations are restricted to the main rotor, and are illustrated. The computational tool used to obtain performance is the lifting line analysis of B65. B65 incorporates experimental data into data banks in order to determine the section lift, drag, and moment characteristics of various airfoils at different Mach numbers and angles of attack. The local flow angle is calculated at user specified radial locations. This flow angle, along with the local Mach number is then cross referenced with the airfoil tables to obtain the local section characteristics. The local characteristics are then integrated together to obtain the entire rotor attributes. Once the clean performance is known, characterization of the type and shape of ice which accretes on the rotor blades is obtained using the analysis of LEWICE. The Interactive Boundary Layer (IBL) method then calculates the 2-D characteristics of the iced airfoil for input into the airfoil data bank of B65. Calculations are restricted to natural ice shedding and it is assumed that no de-icing takes place. Once the new lift, drag, and moment characteristics are known for the entire blade radius, this information is fed into B65, where the iced performance is then calculated.

42 CFR 493.807 - Condition: Reinstatement of laboratories performing nonwaived testing.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., subspecialties, analyte or test, or voluntarily withdraws its certification under CLIA for the failed specialty, subspecialty, or analyte, the laboratory must then demonstrate sustained satisfactory performance on two... reinstatement for certification and Medicare or Medicaid approval in that specialty, subspecialty, analyte or...

42 CFR 493.807 - Condition: Reinstatement of laboratories performing nonwaived testing.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., subspecialties, analyte or test, or voluntarily withdraws its certification under CLIA for the failed specialty, subspecialty, or analyte, the laboratory must then demonstrate sustained satisfactory performance on two... reinstatement for certification and Medicare or Medicaid approval in that specialty, subspecialty, analyte or...

42 CFR 493.807 - Condition: Reinstatement of laboratories performing nonwaived testing.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., subspecialties, analyte or test, or voluntarily withdraws its certification under CLIA for the failed specialty, subspecialty, or analyte, the laboratory must then demonstrate sustained satisfactory performance on two... reinstatement for certification and Medicare or Medicaid approval in that specialty, subspecialty, analyte or...

An Analysis of Rocket Propulsion Testing Costs

NASA Technical Reports Server (NTRS)

Ramirez-Pagan, Carmen P.; Rahman, Shamim A.

2009-01-01

The primary mission at NASA Stennis Space Center (SSC) is rocket propulsion testing. Such testing is generally performed within two arenas: (1) Production testing for certification and acceptance, and (2) Developmental testing for prototype or experimental purposes. The customer base consists of NASA programs, DOD programs, and commercial programs. Resources in place to perform on-site testing include both civil servants and contractor personnel, hardware and software including data acquisition and control, and 6 test stands with a total of 14 test positions/cells. For several business reasons there is the need to augment understanding of the test costs for all the various types of test campaigns. Historical propulsion test data was evaluated and analyzed in many different ways with the intent to find any correlation or statistics that could help produce more reliable and accurate cost estimates and projections. The analytical efforts included timeline trends, statistical curve fitting, average cost per test, cost per test second, test cost timeline, and test cost envelopes. Further, the analytical effort includes examining the test cost from the perspective of thrust level and test article characteristics. Some of the analytical approaches did not produce evidence strong enough for further analysis. Some other analytical approaches yield promising results and are candidates for further development and focused study. Information was organized for into its elements: a Project Profile, Test Cost Timeline, and Cost Envelope. The Project Profile is a snap shot of the project life cycle on a timeline fashion, which includes various statistical analyses. The Test Cost Timeline shows the cumulative average test cost, for each project, at each month where there was test activity. The Test Cost Envelope shows a range of cost for a given number of test(s). The supporting information upon which this study was performed came from diverse sources and thus it was necessary to build several intermediate databases in order to understand, validate, and manipulate data. These intermediate databases (validated historical account of schedule, test activity, and cost) by themselves are of great value and utility. For example, for the Project Profile, we were able to merged schedule, cost, and test activity. This kind of historical account conveys important information about sequence of events, lead time, and opportunities for improvement in future propulsion test projects. The Product Requirement Document (PRD) file is a collection of data extracted from each project PRD (technical characteristics, test requirements, and projection of cost, schedule, and test activity). This information could help expedite the development of future PRD (or equivalent document) on similar projects, and could also, when compared to the actual results, help improve projections around cost and schedule. Also, this file can be sorted by the parameter of interest to perform a visual review of potential common themes or trends. The process of searching, collecting, and validating propulsion test data encountered a lot of difficulties which then led to a set of recommendations for improvement in order to facilitate future data gathering and analysis.

Light aircraft crash safety program

NASA Technical Reports Server (NTRS)

Thomson, R. G.; Hayduk, R. J.

1974-01-01

NASA is embarked upon research and development tasks aimed at providing the general aviation industry with a reliable crashworthy airframe design technology. The goals of the NASA program are: reliable analytical techniques for predicting the nonlinear behavior of structures; significant design improvements of airframes; and simulated full-scale crash test data. The analytical tools will include both simplified procedures for estimating energy absorption characteristics and more complex computer programs for analysis of general airframe structures under crash loading conditions. The analytical techniques being developed both in-house and under contract are described, and a comparison of some analytical predictions with experimental results is shown.

Brewing characteristics of haploid strains isolated from sake yeast Kyokai No. 7.

PubMed

Katou, Taku; Kitagaki, Hiroshi; Akao, Takeshi; Shimoi, Hitoshi

2008-11-01

Sake yeast exhibit various characteristics that make them more suitable for sake brewing compared to other yeast strains. Since sake yeast strains are Saccharomyces cerevisiae heterothallic diploid strains, it is likely that they have heterozygous alleles on homologous chromosomes (heterozygosity) due to spontaneous mutations. If this is the case, segregation of phenotypic traits in haploid strains after sporulation and concomitant meiosis of sake yeast strains would be expected to occur. To examine this hypothesis, we isolated 100 haploid strains from Kyokai No. 7 (K7), a typical sake yeast strain in Japan, and compared their brewing characteristics in small-scale sake-brewing tests. Analyses of the resultant sake samples showed a smooth and continuous distribution of analytical values for brewing characteristics, suggesting that K7 has multiple heterozygosities that affect brewing characteristics and that these heterozygous alleles do segregate after sporulation. Correlation and principal component analyses suggested that the analytical parameters could be classified into two groups, indicating fermentation ability and sake flavour. (c) 2008 John Wiley & Sons, Ltd.

Anthropometric and mass distribution characteristics of the adult female.

DOT National Transportation Integrated Search

1983-09-01

This study of 46 living adult females is part of a long-range research program designed to establish valid analytical relationships between readily measured body dimensions and mass distribution characteristics of living populations. Presented in thi...

Assessing organizational change in multisector community health alliances.

PubMed

Alexander, Jeffrey A; Hearld, Larry R; Shi, Yunfeng

2015-02-01

The purpose of this article was to identify some common organizational features of multisector health care alliances (MHCAs) and the analytic challenges presented by those characteristics in assessing organizational change. Two rounds of an Internet-based survey of participants in 14 MHCAs. We highlight three analytic challenges that can arise when quantitatively studying the organizational characteristics of MHCAs-assessing change in MHCA organization, assessment of construct reliability, and aggregation of individual responses to reflect organizational characteristics. We illustrate these issues using a leadership effectiveness scale (12 items) validated in previous research and data from 14 MHCAs participating in the Robert Wood Johnson Foundation's Aligning Forces for Quality (AF4Q) program. High levels of instability and turnover in MHCA membership create challenges in using survey data to study changes in key organizational characteristics of MHCAs. We offer several recommendations to diagnose the source and extent of these problems. © Health Research and Educational Trust.

Potassium sodium chloride integrated microconduits in a potentiometric analytical system.

PubMed

Hongbo, C; Junyan, S

1991-09-01

The preparation and application of a K(+), Na(+) and Cl(-) integrated microconduit potentiometric analytical system with tubular ion-selective electrodes (ISEs), microvalve, chemfold, electrostatic and pulse inhibitors is described. Electrochemical characteristics of the tubular ISEs and integrated microconduit FIA-ISEs were studied. The contents of K(+), Na(+) and Cl(-) in soil, water and serum were determined with the device. The analytical results agreed well with those obtained by flame photometric and silver nitrate volumetric methods.

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

Owens, W.W.; Sullivan, H.H.

Electroless nicke-plate characteristics are substantially influenced by percent phosphorous concentrations. Available ASTM analytical methods are designed for phosphorous concentrations of less than one percent compared to the 4.0 to 20.0% concentrations common in electroless nickel plate. A variety of analytical adaptations are applied through the industry resulting in poor data continuity. This paper presents a statistical comparison of five analytical methods and recommends accurate and precise procedures for use in percent phosphorous determinations in electroless nickel plate. 2 figures, 1 table.

Sigma metrics as a tool for evaluating the performance of internal quality control in a clinical chemistry laboratory.

PubMed

Kumar, B Vinodh; Mohan, Thuthi

2018-01-01

Six Sigma is one of the most popular quality management system tools employed for process improvement. The Six Sigma methods are usually applied when the outcome of the process can be measured. This study was done to assess the performance of individual biochemical parameters on a Sigma Scale by calculating the sigma metrics for individual parameters and to follow the Westgard guidelines for appropriate Westgard rules and levels of internal quality control (IQC) that needs to be processed to improve target analyte performance based on the sigma metrics. This is a retrospective study, and data required for the study were extracted between July 2015 and June 2016 from a Secondary Care Government Hospital, Chennai. The data obtained for the study are IQC - coefficient of variation percentage and External Quality Assurance Scheme (EQAS) - Bias% for 16 biochemical parameters. For the level 1 IQC, four analytes (alkaline phosphatase, magnesium, triglyceride, and high-density lipoprotein-cholesterol) showed an ideal performance of ≥6 sigma level, five analytes (urea, total bilirubin, albumin, cholesterol, and potassium) showed an average performance of <3 sigma level and for level 2 IQCs, same four analytes of level 1 showed a performance of ≥6 sigma level, and four analytes (urea, albumin, cholesterol, and potassium) showed an average performance of <3 sigma level. For all analytes <6 sigma level, the quality goal index (QGI) was <0.8 indicating the area requiring improvement to be imprecision except cholesterol whose QGI >1.2 indicated inaccuracy. This study shows that sigma metrics is a good quality tool to assess the analytical performance of a clinical chemistry laboratory. Thus, sigma metric analysis provides a benchmark for the laboratory to design a protocol for IQC, address poor assay performance, and assess the efficiency of existing laboratory processes.

Design and Simulation of a MEMS Structure for Electrophoretic and Dielectrophoretic Separation of Particles by Contactless Electrodes

NASA Technical Reports Server (NTRS)

Shaw, Harry C.

2007-01-01

Rapid identification of pathogenic bacterial species is an important factor in combating public health problems such as E. coli contamination. Food and waterborne pathogens account for sickness in 76 million people annually (CDC). Diarrheagenic E. coli is a major source of gastrointestinal illness. Severe sepsis and Septicemia within the hospital environment are also major problems. 75 1,000 cases annually with a 30-50% mortality rate (Crit Care Med, July '01, Vol. 29, 1303-10). Patient risks run the continuum from fever to organ failure and death. Misdiagnosis or inappropriate treatment increases mortality. There exists a need for rapid screening of samples for identification of pathogenic species (Certain E. coli strains are essential for health). Critical to the identification process is the ability to isolate analytes of interest rapidly. This poster discusses novel devices for the separation of particles on the basis of the dielectric properties, mass and surface charge characteristics is presented. Existing designs involve contact between electrode surfaces and analyte medium resulting in contamination of the electrode bearing elements Two different device designs using different bulk micromachining MEMS processes (PolyMUMPS and a PyrexBIGold electrode design) are presented. These designs cover a range of particle sizes from small molecules through eucaryotic cells. The application of separation of bacteria is discussed in detail. Simulation data for electrostatic and microfluidic characteristics are provided. Detailed design characteristics and physical features of the as fabricated PolyMUMPS design are provided. Analysis of the simulation data relative to the expected performance of the devices will be provided and subsequent conclusions discussed.

10 CFR 26.168 - Blind performance testing.

Code of Federal Regulations, 2014 CFR

2014-01-01

... analyte and must be certified by immunoassay and confirmatory testing; (2) Drug positive. These samples must contain a measurable amount of the target drug or analyte in concentrations ranging between 150... performance test sample must contain a measurable amount of the target drug or analyte in concentrations...

10 CFR 26.168 - Blind performance testing.

Code of Federal Regulations, 2010 CFR

2010-01-01

... analyte and must be certified by immunoassay and confirmatory testing; (2) Drug positive. These samples must contain a measurable amount of the target drug or analyte in concentrations ranging between 150... performance test sample must contain a measurable amount of the target drug or analyte in concentrations...

10 CFR 26.168 - Blind performance testing.

Code of Federal Regulations, 2011 CFR

2011-01-01

... analyte and must be certified by immunoassay and confirmatory testing; (2) Drug positive. These samples must contain a measurable amount of the target drug or analyte in concentrations ranging between 150... performance test sample must contain a measurable amount of the target drug or analyte in concentrations...

10 CFR 26.168 - Blind performance testing.

Code of Federal Regulations, 2013 CFR

2013-01-01

... analyte and must be certified by immunoassay and confirmatory testing; (2) Drug positive. These samples must contain a measurable amount of the target drug or analyte in concentrations ranging between 150... performance test sample must contain a measurable amount of the target drug or analyte in concentrations...

10 CFR 26.168 - Blind performance testing.

Code of Federal Regulations, 2012 CFR

2012-01-01

... analyte and must be certified by immunoassay and confirmatory testing; (2) Drug positive. These samples must contain a measurable amount of the target drug or analyte in concentrations ranging between 150... performance test sample must contain a measurable amount of the target drug or analyte in concentrations...

Biological diagnosis of von Willebrand disease: analytical characteristics of Innovance vWF:Ac assay kit on STA-R Evolution Expert series analyzer (Stago).

PubMed

Florin, Cécile; Garraud, Olivier; Molliex, Serge; Tardy, Brigitte; Campos, Lydia; Scherrer, Carine

2016-06-01

The Innovance VWF:Ac test (Siemens) has the particularity to assess the binding capacity of von Willebrand factor (VWF) to recombinant platelet GPIb mutated in the absence of ristocetin. Our study aimed to evaluate and validate according to standard NF EN ISO 15189 the original protocol adaptation on STA-R Evolution series analyser (Diagnostica Stago). We evaluated the performance in terms of imprecision and we validate additional parameters necessary in range B as recommended by the SH GTA 04 (Cofrac). We compared the new assay with the reference assay: ristocetin cofactor activity (VWF:RCo) performed on the BCS-XP analyser by testing retrospectively samples from 82 healthy normal subjects and 61 patients with von Willebrand disease (VWD). This new assay is consistent with objectives set in terms of imprecision with CV around 4%. Excepted limit of quantification higher, additional parameters evaluated in range B have been validated. The Innovance VWF: Ac assay allowed the detection of all deficits of VWF already detected by the VWF:RCo test on the BCS-XP. This adjustment on STA-R analyser therefore has satisfactory analytical performance criteria. Apart from the limit of quantification, this reagent can be used according to the recommendations specified in the original protocol adaptation. Its performance and compatibility with the spot measurement allow the diagnosis and therapeutic monitoring of VWD according to current requirements and guidelines.

Analytical core loss calculations for magnetic materials used in high frequency high power converter applications. Ph.D. Thesis - Toledo Univ.

NASA Technical Reports Server (NTRS)

Triner, J. E.

1979-01-01

The basic magnetic properties under various operating conditions encountered in the state-of-the-art DC-AC/DC converters are examined. Using a novel core excitation circuit, the basic B-H and loss characteristics of various core materials may be observed as a function of circuit configuration, frequency of operation, input voltage, and pulse-width modulation conditions. From this empirical data, a mathematical loss characteristics equation is developed to analytically predict the specific core loss of several magnetic materials under various waveform excitation conditions.

Incorporation of metal-organic framework HKUST-1 into porous polymer monolithic capillary columns to enhance the chromatographic separation of small molecules.

PubMed

Yang, Shengchao; Ye, Fanggui; Lv, Qinghui; Zhang, Cong; Shen, Shufen; Zhao, Shulin

2014-09-19

Metal-organic framework (MOF) HKUST-1 nanoparticles have been incorporated into poly(glycidyl methacrylate-co-ethylene dimethacrylate) (HKUST-1-poly(GMA-co-EDMA)) monoliths to afford stationary phases with enhanced chromatographic performance of small molecules in the reversed phase capillary liquid chromatography. The effect of HKUST-1 nanoparticles in the polymerization mixture on the performance of the monolithic column was explored in detail. While the bare poly(GMA-co-EDMA) monolith exhibited poor resolution (Rs<1.0) and low efficiency (800-16,300plates/m), addition of a small amount of HKUST-1 nanoparticles to the polymerization mixture provide high increased resolution (Rs≥1.3) and high efficiency ranged from 16,300 to 44,300plates/m. Chromatographic performance of HKUST-1-poly(GMA-co-EDMA) monolith was demonstrated by separation of various analytes including polycyclic aromatic hydrocarbons, ethylbenzene and styrene, phenols and aromatic acids using a binary polar mobile phase (CH3CN/H2O). The HKUST-1-poly(GMA-co-EDMA) monolith displayed enhanced hydrophobic and π-π interaction characteristics in the reversed phase separation of test analytes compared to the bare poly(GMA-co-EDMA) monolith. The experiment results showed that HKUST-1-poly(GMA-co-EDMA) monoliths are an alternative to enhance the chromatographic separation of small molecules. Copyright © 2014 Elsevier B.V. All rights reserved.

Designing electrochemical interfaces with functionalized magnetic nanoparticles and wrapped carbon nanotubes as platforms for the construction of high-performance bienzyme biosensors.

PubMed

Eguílaz, Marcos; Villalonga, Reynaldo; Yáñez-Sedeño, Paloma; Pingarrón, José M

2011-10-15

The design of a novel biosensing electrode surface, combining the advantages of magnetic ferrite nanoparticles (MNPs) functionalized with glutaraldehyde (GA) and poly(diallyldimethylammonium chloride) (PDDA)-coated multiwalled carbon nanotubes (MWCNTs) as platforms for the construction of high-performance multienzyme biosensors, is reported in this work. Before the immobilization of enzymes, GA-MNP/PDDA/MWCNT composites were prepared by wrapping of carboxylated MWCNTs with positively charged PDDA and interaction with GA-functionalized MNPs. The nanoconjugates were characterized by scanning electron microscopy (SEM) and electrochemistry. The electrode platform was used to construct a bienzyme biosensor for the determination of cholesterol, which implied coimmobilization of cholesterol oxidase (ChOx) and peroxidase (HRP) and the use of hydroquinone as redox mediator. Optimization of all variables involved in the preparation and analytical performance of the bienzyme electrode was accomplished. At an applied potential of -0.05 V, a linear calibration graph for cholesterol was obtained in the 0.01-0.95 mM concentration range. The detection limit (0.85 μM), the apparent Michaelis-Menten constant (1.57 mM), the stability of the biosensor, and the calculated activation energy can be advantageously compared with the analytical characteristics of other CNT-based cholesterol biosensors reported in the literature. Analysis of human serum spiked with cholesterol at different concentration levels yielded recoveries between 100% and 103% © 2011 American Chemical Society

The contribution of Raman spectroscopy to the analytical quality control of cytotoxic drugs in a hospital environment: eliminating the exposure risks for staff members and their work environment.

PubMed

Bourget, Philippe; Amin, Alexandre; Vidal, Fabrice; Merlette, Christophe; Troude, Pénélope; Baillet-Guffroy, Arlette

2014-08-15

The purpose of the study was to perform a comparative analysis of the technical performance, respective costs and environmental effect of two invasive analytical methods (HPLC and UV/visible-FTIR) as compared to a new non-invasive analytical technique (Raman spectroscopy). Three pharmacotherapeutic models were used to compare the analytical performances of the three analytical techniques. Statistical inter-method correlation analysis was performed using non-parametric correlation rank tests. The study's economic component combined calculations relative to the depreciation of the equipment and the estimated cost of an AQC unit of work. In any case, analytical validation parameters of the three techniques were satisfactory, and strong correlations between the two spectroscopic techniques vs. HPLC were found. In addition, Raman spectroscopy was found to be superior as compared to the other techniques for numerous key criteria including a complete safety for operators and their occupational environment, a non-invasive procedure, no need for consumables, and a low operating cost. Finally, Raman spectroscopy appears superior for technical, economic and environmental objectives, as compared with the other invasive analytical methods. Copyright © 2014 Elsevier B.V. All rights reserved.

Method of characteristics for three-dimensional axially symmetrical supersonic flows.

NASA Technical Reports Server (NTRS)

Sauer, R

1947-01-01

An approximation method for three-dimensional axially symmetrical supersonic flows is developed; it is based on the characteristics theory (represented partly graphically, partly analytically). Thereafter this method is applied to the construction of rotationally symmetrical nozzles. (author)

Study of a Vuilleumier cycle cryogenic refrigerator for detector cooling on the limb scanning infrared radiometer

NASA Technical Reports Server (NTRS)

Russo, S. C.

1976-01-01

A program to detect and monitor the presence of trace constituents in the earth's atmosphere by using the Limb Scanning Infrared Radiometer (LSIR) is reported. The LSIR, which makes radiometric measurements of the earth's limb radiance profile from a space platform, contains a detector assembly that must be cooled to a temperature of 65 + or - 2 K. The feasibility of cooling the NASA-type detector package with Vuilleumier (VM) cryogenic refrigerator was investigated to develop a preliminary conceptual design of a VM refrigerator that is compatible with a flight-type LSIR instrument. The scope of the LSIR program consists of analytical and design work to establish the size, weight, power consumption, interface requirements, and other important characteristics of a cryogenic cooler that would meet the requirements of the LSIR. The cryogenic cooling requirements under the conditions that NASA specified were defined. Following this, a parametric performance analysis was performed to define the interrelationships between refrigeration characteristics and mission requirements. This effort led to the selection of an optimum refrigerator design for the LSIR mission.

Determination of carbohydrates in honey and milk by capillary electrophoresis in combination with graphene-cobalt microsphere hybrid paste electrodes.

PubMed

Liang, Peipei; Sun, Motao; He, Peimin; Zhang, Luyan; Chen, Gang

2016-01-01

A graphene-cobalt microsphere (CoMS) hybrid paste electrode was developed for the determination of carbohydrates in honey and milk in combination with capillary electrophoresis (CE). The performance of the electrodes was demonstrated by detecting mannitol, sucrose, lactose, glucose, and fructose after CE separation. The five analytes were well separated within 9 min in a 40 cm long capillary at a separation voltage of 12 kV. The electrodes exhibited pronounced electrocatalytic activity, lower detection potentials, enhanced signal-to-noise characteristics, and higher reproducibility. The relation between peak current and analyte concentration was linear over about three orders of magnitude. The proposed method had been employed to determine lactose in bovine milk and glucose and fructose in honey with satisfactory results. Because only electroactive substances in the samples could be detected on the paste electrode, the electropherograms of both food samples were simplified to some extent. Copyright © 2015 Elsevier Ltd. All rights reserved.

RapidIO as a multi-purpose interconnect

NASA Astrophysics Data System (ADS)

Baymani, Simaolhoda; Alexopoulos, Konstantinos; Valat, Sébastien

2017-10-01

RapidIO (http://rapidio.org/) technology is a packet-switched high-performance fabric, which has been under active development since 1997. Originally meant to be a front side bus, it developed into a system level interconnect which is today used in all 4G/LTE base stations world wide. RapidIO is often used in embedded systems that require high reliability, low latency and scalability in a heterogeneous environment - features that are highly interesting for several use cases, such as data analytics and data acquisition (DAQ) networks. We will present the results of evaluating RapidIO in a data analytics environment, from setup to benchmark. Specifically, we will share the experience of running ROOT and Hadoop on top of RapidIO. To demonstrate the multi-purpose characteristics of RapidIO, we will also present the results of investigating RapidIO as a technology for high-speed DAQ networks using a generic multi-protocol event-building emulation tool. In addition we will present lessons learned from implementing native ports of CERN applications to RapidIO.

Pricing foreign equity option under stochastic volatility tempered stable Lévy processes

NASA Astrophysics Data System (ADS)

Gong, Xiaoli; Zhuang, Xintian

2017-10-01

Considering that financial assets returns exhibit leptokurtosis, asymmetry properties as well as clustering and heteroskedasticity effect, this paper substitutes the logarithm normal jumps in Heston stochastic volatility model by the classical tempered stable (CTS) distribution and normal tempered stable (NTS) distribution to construct stochastic volatility tempered stable Lévy processes (TSSV) model. The TSSV model framework permits infinite activity jump behaviors of return dynamics and time varying volatility consistently observed in financial markets through subordinating tempered stable process to stochastic volatility process, capturing leptokurtosis, fat tailedness and asymmetry features of returns. By employing the analytical characteristic function and fast Fourier transform (FFT) technique, the formula for probability density function (PDF) of TSSV returns is derived, making the analytical formula for foreign equity option (FEO) pricing available. High frequency financial returns data are employed to verify the effectiveness of proposed models in reflecting the stylized facts of financial markets. Numerical analysis is performed to investigate the relationship between the corresponding parameters and the implied volatility of foreign equity option.

Enantioseparation by Capillary Electrophoresis Using Ionic Liquids as Chiral Selectors.

PubMed

Greño, Maider; Marina, María Luisa; Castro-Puyana, María

2018-11-02

Capillary electrophoresis (CE) is one of the most widely employed analytical techniques to achieve enantiomeric separations. In spite of the fact that there are many chiral selectors commercially available to perform enantioseparations by CE, one of the most relevant topics in this field is the search for new selectors capable of providing high enantiomeric resolutions. Chiral ionic liquids (CILs) have interesting characteristics conferring them a high potential in chiral separations although only some of them are commercially available. The aim of this article is to review all the works published on the use of CILs as chiral selectors in the development of enantioselective methodologies by CE, covering the period from 2006 (when the first research work on this topic was published) to 2017. The use of CILs as sole chiral selectors, as chiral selectors in dual systems or as chiral ligands will be considered. This review also provides detailed analytical information on the experimental conditions used to carry out enantioseparations in different fields as well as on the separation mechanism involved.

2D modeling based comprehensive analysis of short channel effects in DMG strained VSTB FET

NASA Astrophysics Data System (ADS)

Saha, Priyanka; Banerjee, Pritha; Sarkar, Subir Kumar

2018-06-01

The paper aims to develop two dimensional analytical model of the proposed dual material (DM) Vertical Super Thin Body (VSTB) strained Field Effect Transistor (FET) with focus on its short channel behaviour in nanometer regime. Electrostatic potential across gate/channel and dielectric wall/channel interface is derived by solving 2D Poisson's equation with parabolic approximation method by applying appropriate boundary conditions. Threshold voltage is then calculated by using the criteria of minimum surface potential considering both gate and dielectric wall side potential. Performance analysis of the present structure is demonstrated in terms of potential, electric field, threshold voltage characteristics and subthreshold behaviour by varying various device parameters and applied biases. Effect of application of strain in channel is further explored to establish the superiority of the proposed device in comparison to conventional VSTB FET counterpart. All analytical results are compared with Silvaco ATLAS device simulated data to substantiate the accuracy of our derived model.

Population Spotting Using Big Data: Validating the Human Performance Concept of Operations Analytic Vision

DTIC Science & Technology

2017-01-01

AFRL-SA-WP-SR-2017-0001 Population Spotting Using “ Big Data ”: Validating the Human Performance Concept of Operations Analytic Vision...TITLE AND SUBTITLE Population Spotting Using “ Big Data ”: Validating the Human Performance Concept of Operations Analytic Vision 5a. CONTRACT...STINFO COPY NOTICE AND SIGNATURE PAGE Using Government drawings, specifications, or other data included in this document for any

Analysis of sound absorption performance of an electroacoustic absorber using a vented enclosure

NASA Astrophysics Data System (ADS)

Cho, Youngeun; Wang, Semyung; Hyun, Jaeyub; Oh, Seungjae; Goo, Seongyeol

2018-03-01

The sound absorption performance of an electroacoustic absorber (EA) is primarily influenced by the dynamic characteristics of the loudspeaker that acts as the actuator of the EA system. Therefore, the sound absorption performance of the EA is maximum at the resonance frequency of the loudspeaker and tends to degrade in the low-frequency and high-frequency bands based on this resonance frequency. In this study, to adjust the sound absorption performance of the EA system in the low-frequency band of approximately 20-80 Hz, an EA system using a vented enclosure that has previously been used to enhance the radiating sound pressure of a loudspeaker in the low-frequency band, is proposed. To verify the usefulness of the proposed system, two acoustic environments are considered. In the first acoustic environment, the vent of the vented enclosure is connected to an external sound field that is distinct from the sound field coupled to the EA. In this case, the acoustic effect of the vented enclosure on the performance of the EA is analyzed through an analytical approach using dynamic equations and an impedance-based equivalent circuit. Then, it is verified through numerical and experimental approaches. Next, in the second acoustic environment, the vent is connected to the same external sound field as the EA. In this case, the effect of the vented enclosure on the EA is investigated through an analytical approach and finally verified through a numerical approach. As a result, it is confirmed that the characteristics of the sound absorption performances of the proposed EA system using the vented enclosure in the two acoustic environments considered in this study are different from each other in the low-frequency band of approximately 20-80 Hz. Furthermore, several case studies on the change tendency of the performance of the EA using the vented enclosure according to the critical design factors or vent number for the vented enclosure are also investigated. In the future, even if the proposed EA system using a vented enclosure is extended to a large number of arrays required for 3D sound field control, it is expected to be an attractive solution that can contribute to an improvement in low-frequency noise reduction without causing economic and system complexity problems.

Goals and Characteristics of Long-Term Care Programs: An Analytic Model.

ERIC Educational Resources Information Center

Braun, Kathryn L.; Rose, Charles L.

1989-01-01

Used medico-social analytic model to compare five long-term care programs: Skilled Nursing Facility-Intermediate Care Facility (SNF-ICF) homes, ICF homes, foster homes, day hospitals, and home care. Identified similarities and differences among programs. Preliminary findings suggest that model is useful in the evaluation and design of long-term…

Child Negative Emotionality and Parenting from Infancy to Preschool: A Meta-Analytic Review

ERIC Educational Resources Information Center

Paulussen-Hoogeboom, Marja C.; Stams, Geert Jan J. M.; Hermanns, Jo M. A.; Peetsma, Thea T. D.

2007-01-01

This meta-analytic review (k = 62 studies; N = 7,613 mother-child dyads) shows that effect sizes for the association between child negative emotionality and parenting were generally small and were moderated by sample and measurement characteristics. The association between more child negative emotionality and less supportive parenting was…

Reflecting Solutions of High Order Elliptic Differential Equations in Two Independent Variables Across Analytic Arcs. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Carleton, O.

1972-01-01

Consideration is given specifically to sixth order elliptic partial differential equations in two independent real variables x, y such that the coefficients of the highest order terms are real constants. It is assumed that the differential operator has distinct characteristics and that it can be factored as a product of second order operators. By analytically continuing into the complex domain and using the complex characteristic coordinates of the differential equation, it is shown that its solutions, u, may be reflected across analytic arcs on which u satisfies certain analytic boundary conditions. Moreover, a method is given whereby one can determine a region into which the solution is extensible. It is seen that this region of reflection is dependent on the original domain of difinition of the solution, the arc and the coefficients of the highest order terms of the equation and not on any sufficiently small quantities; i.e., the reflection is global in nature. The method employed may be applied to similar differential equations of order 2n.

Participation and performance in INSTAND multi-analyte molecular genetics external quality assessment schemes from 2006 to 2012.

PubMed

Maly, Friedrich E; Fried, Roman; Spannagl, Michael

2014-01-01

INSTAND e.V. has provided Molecular Genetics Multi-Analyte EQA schemes since 2006. EQA participation and performance were assessed from 2006 - 2012. From 2006 to 2012, the number of analytes in the Multi-Analyte EQA schemes rose from 17 to 53. Total number of results returned rose from 168 in January 2006 to 824 in August 2012. The overall error rate was 1.40 +/- 0.84% (mean +/- SD, N = 24 EQA dates). From 2006 to 2012, no analyte was reported 100% correctly. Individual participant performance was analysed for one common analyte, Lactase (LCT) T-13910C. From 2006 to 2012, 114 laboratories participated in this EQA. Of these, 10 laboratories (8.8%) reported at least one wrong result during the whole observation period. All laboratories reported correct results after their failure incident. In spite of the low overall error rate, EQA will continue to be important for Molecular Genetics.

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.

Insights in the analytical performance of neat metal-organic frameworks in the determination of pollutants of different nature from waters using dispersive miniaturized solid-phase extraction and liquid chromatography.

PubMed

Rocío-Bautista, Priscilla; Pino, Verónica; Pasán, Jorge; López-Hernández, Irene; Ayala, Juan H; Ruiz-Pérez, Catalina; Afonso, Ana M

2018-03-01

Five metal-organic frameworks (MOFs), specifically HKUST-1, MOF-5(Zn), MIL-53(Al), UiO-64 and MOF-74(Zn) are synthesized, characterized, and utilized in a miniaturized solid-phase extraction method under dispersive mode (D-µSPE) for the determination of six pollutants of different nature, including one polycyclic aromatic hydrocarbon, two hormones, two drugs, and one disinfectant, from environmental waters (tap water and wastewater). A discussion of possible interactions justifying the partitioning of target analytes to the MOFs is included, considering not only the analytes' physicochemical characteristics but also those of MOFs: metal nature, structural environment of MOF pores, pore size and pore aperture widths, among others. MIL-53(Al) is selected for its versatility and high extraction efficiency for the target compounds. The D-µSPE method using MIL-53(Al) is optimized and used in combination with high-performance liquid chromatography (HPLC) with diode array detector (DAD) or liquid-chromatography with time-of-flight mass spectrometric detector (LC-TOF). Under optimum conditions, only 5mg of MIL-53(Al) are required for 10mL of water, with the aid of 5min of vortex and 5min of centrifugation. Elution is accomplished with 200µL of acetonitrile (3 times), and evaporation down to 100µL before LC injection. Detection limits down to 0.040μgL -1 for triclosan and 0.013μgL -1 for atrazine are obtained for the entire method using HPLC-DAD and LC-TOF, respectively. The method, operating at low spiked levels (2µgL -1 for HPLC-DAD and 0.7µgL -1 for LC-TOF), is also characterized for average relative recoveries of 109% and 105%; relative standard deviation values lower than 8.7% and 7.5%; and average extraction efficiencies of 41.2% and 49.1%; using HPLC-DAD and LC-TOF, respectively; while demonstrating adequate analytical performance with complex samples such as wastewaters. Copyright © 2017 Elsevier B.V. All rights reserved.

Enzyme-linked immunoassay for plasma-free metanephrines in the biochemical diagnosis of phaeochromocytoma in adults is not ideal.

PubMed

Mullins, Fiona; O'Shea, Paula; FitzGerald, Roland; Tormey, William

2011-10-08

The aim of the study was to define the analytical and diagnostic performance of the Labor Diagnostica Nord (LDN) 2-Met plasma ELISA assay for fractionated plasma metanephrines in the biochemical diagnosis of phaeochromocytoma. The stated manufacturer's performance characteristics were assessed. Clinical utility was evaluated against liquid chromatography tandem mass spectrometry (LC-MS/MS) using bias, sensitivity and specificity outcomes. Samples (n=73) were collected from patients in whom phaeochromocytoma had been excluded (n=60) based on low probability of disease, repeat negative testing for urinary fractionated catecholamines and metanephrines, lack of radiological and histological evidence of a tumour and from a group (n=13) in whom the tumour had been histologically confirmed. Blood collected into k(2)EDTA tubes was processed within 30 min. Separated plasma was aliquoted (×2) and frozen at -40°C prior to analyses. One aliquot was analysed for plasma metanephrines using the LDN 2-Met ELISA and the other by LC-MS/MS. The mean bias of -32% for normetanephrine (ELISA) when compared to the reference method (LC-MS/MS) makes under-diagnosis of phaeochromocytoma likely. The sensitivity of the assay (100%) was equal to the reference method, but specificity (88.3%) lower than the reference method (95%), making it less than optimum for the biochemical diagnosis of phaeochromocytoma. Plasma-free metanephrines as measured by Labor Diagnostica Nord (LDN) 2-Met ELISA do not display test characteristics that would support their introduction or continuation as part of a screening protocol for the biochemical detection of phaeochromocytoma unless the calibration problem identified is corrected and other more accurate and analytically specific methods remain unavailable.

Analytical assessment about the simultaneous quantification of releasable pharmaceutical relevant inorganic nanoparticles in tap water and domestic waste water.

PubMed

Krystek, Petra; Bäuerlein, Patrick S; Kooij, Pascal J F

2015-03-15

For pharmaceutical applications, the use of inorganic engineered nanoparticles is of growing interest while silver (Ag) and gold (Au) are the most relevant elements. A few methods were developed recently but the validation and the application testing were quite limited. Therefore, a routinely suitable multi element method for the identification of nanoparticles of different sizes below 100 nm and elemental composition by applying asymmetric flow field flow fraction (AF4) - inductively coupled plasma mass spectrometry (ICPMS) is developed. A complete validation model of the quantification of releasable pharmaceutical relevant inorganic nanoparticles based on Ag and Au is presented for the most relevant aqueous matrices of tap water and domestic waste water. The samples are originated from locations in the Netherlands and it is of great interest to study the unwanted presence of Ag and Au as nanoparticle residues due to possible health and environmental risks. During method development, instability effects are observed for 60 nm and 70 nm Ag ENPs with different capping agents. These effects are studied more closely in relation to matrix effects. Besides the methodological aspects, the obtained analytical results and relevant performance characteristics (e.g. measuring range, limit of detection, repeatability, reproducibility, trueness, and expanded uncertainty of measurement) are determined and discussed. For the chosen aqueous matrices, the results of the performance characteristics are significantly better for Au ENPs in comparison to Ag ENPs; e.g. repeatability and reproducibility are below 10% for all Au ENPs respectively maximal 27% repeatability for larger Ag ENPs. The method is a promising tool for the simultaneous determination of releasable pharmaceutical relevant inorganic nanoparticles. Copyright © 2014 Elsevier B.V. All rights reserved.

Analysis of co-eluted isomers of high-molecular weight polycyclic aromatic hydrocarbons in high performance liquid chromatography fractions via solid-phase nanoextraction and time-resolved Shpol'skii spectroscopy.

PubMed

Wilson, Walter B; Campiglia, Andres D

2011-09-28

We present an accurate method for the determination of isomers of high-molecular weight polycyclic aromatic hydrocarbons co-eluted in HPLC fractions. The feasibility of this approach is demonstrated with two isomers of molecular weight 302 with identical mass fragmentation patterns, namely dibenzo[a,i]pyrene and naphtho[2,3-a]pyrene. Qualitative and quantitative analysis is carried out via laser-excited time-resolved Shpol'skii spectroscopy at liquid helium temperature. Unambiguous identification of co-eluted isomers is based on their characteristic 4.2 K line-narrowed spectra in n-octane as well as their fluorescence lifetimes. Pre-concentration of HPLC fractions prior to spectroscopic analysis is performed with the aid of gold nanoparticles via an environmentally friendly procedure. In addition to the two co-eluted isomers, the analytical figures of merit of the entire procedure were evaluated with dibenzo[a,l]pyrene, dibenzo[a,h]pyrene and dibenzo[a,e]pyrene. The analytical recoveries from drinking water samples varied between 98.2±5.5 (dibenzo[a,l]pyrene) and 102.7±3.2% (dibenzo[a,i]pyrene). The limits of detection ranged from 51.1 ng L(-1) (naphtho[2,3-a]pyrene) to 154 ng L(-1) (dibenzo[a,e]pyrene). The excellent analytical figures of merit associated to its HPLC compatibility makes this approach an attractive alternative for the analysis of co-eluted isomers with identical mass spectra. Copyright © 2011 Elsevier B.V. All rights reserved.

Configuration development for ROMENET

NASA Astrophysics Data System (ADS)

Rhue, Lawrence

1989-10-01

A plan prepared by RJO Enterprises and BBN Communications Corporation (BBNCC) for the design of ROMENET, a DDN-like testbed for the Rome Air Development Center (RADC) Wide Area Networks (WAN) laboratory is presented. The ROMENET is intended to provide RADC with the ability to test and evaluate the performance and vulnerability of the Defense Data Network (DDN) technologies in support of specific Major Command programs and activities at RADC. It will also support experimentation with packet switched network technologies and includes facilities to analytically evaluate the performance of the network and its associated equipment and media. In addition, ROMENET will provide a simulation vehicle for controlled interference or jamming into the media for vulnerability assessment. Through interfaces with the RADC Battle Management Laboratory (BML), ROMENET will allow the Air Force to assess the restorative and performance characteristics of the network under stressed conditions. The closed environment of ROMENET makes it ideal for creating and testing routing algorithms and network control protocols.

Feasibility model of a high reliability five-year tape transport, Volume 1. [development, performance, and test results

NASA Technical Reports Server (NTRS)

Eshleman, R. L.; Meyers, A. P.; Davidson, W. A.; Gortowski, R. C.; Anderson, M. E.

1973-01-01

The development, performance, and test results for the spaceborne magnetic tape transport are discussed. An analytical model of the tape transport was used to optimize its conceptual design. Each of the subsystems was subjected to reliability analyses which included structural integrity, maintenance of system performance within acceptable bounds, and avoidance of fatigue failure. These subsystems were also compared with each other in order to evaluate reliability characteristics. The transport uses no mechanical couplings. Four drive motors, one for each reel and one for each of two capstans, are used in a differential mode. There are two hybrid, spherical, cone tapered-crown rollers for tape guidance. Storage of the magnetic tape is provided by a reel assembly which includes the reel, a reel support structure and bearings, dust seals, and a dc drive motor. A summary of transport test results on tape guidance, flutter, and skew is provided.

Development of a high-specific-speed centrifugal compressor

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

Rodgers, C.

1997-07-01

This paper describes the development of a subscale single-stage centrifugal compressor with a dimensionless specific speed (Ns) of 1.8, originally designed for full-size application as a high volume flow, low pressure ratio, gas booster compressor. The specific stage is noteworthy in that it provides a benchmark representing the performance potential of very high-specific-speed compressors, of which limited information is found in the open literature. Stage and component test performance characteristics are presented together with traverse results at the impeller exit. Traverse test results were compared with recent CFD computational predictions for an exploratory analytical calibration of a very high-specific-speed impellermore » geometry. The tested subscale (0.583) compressor essentially satisfied design performance expectations with an overall stage efficiency of 74% including, excessive exit casing losses. It was estimated that stage efficiency could be increased to 81% with exit casing losses halved.« less