Studies of design parameters for interferometric methane sensors
NASA Astrophysics Data System (ADS)
Wykes, John S.; Willett, Martin J.; Croydon, W. F.
1992-08-01
Methane detectors based on the absorption of infrared radiation show some promise as the basis of sensitive and accurate industrial instrumentation. Comb filter methods that utilize the vibration-rotation structure of the methane spectrum in an optically efficient manner have recently aroused particular interest in this context. We describe a mathematical model to simulate the behavior of scanning interferometric comb filters in methane detection systems and discuss the use of the model to investigate optimum design parameters for such systems. The behavior of prototype methane detectors based on scanning Fabry-Perot and Mach Zehnder interferometers is briefly reported. Possible techniques for obtaining further improvements in the design of comb filters for methane detection are suggested.
Design Parameter Studies of Emission-Based Iron Opacity Measurements
NASA Astrophysics Data System (ADS)
Martin, Madison E.; London, Richard A.; Goluoglu, Sedat; Whitley, Heather D.
2016-10-01
Opacity is a critical parameter in the transport of radiation in systems such as inertial confinement fusion capsules and stars. The resolution of current disagreements between solar models and helioseismological observations would benefit from experimental validation of theoretical opacity models. Short pulse lasers can be used to heat targets to higher temperatures and densities than long pulse lasers and pulsed power machines, thus potentially enabling access to x-ray emission spectra at conditions relevant to solar models. The radiation-hydrodynamic code HYDRA is used to investigate the effects of modifying laser energy, laser pulse length, and target dimensions on the plasma conditions, x-ray emission, and inferred opacity of a buried layer iron target. The accuracy of the opacity inference is sensitive to tamper emission and optical depth effects. An example design that reaches temperatures and densities relevant to the radiative zone of the sun while reducing optical depth and tamper emission effects will be discussed. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Lawrence Livermore National Security, LLC.
Parameter Study of the LIFE Engine Nuclear Design
Kramer, K J; Meier, W R; Latkowski, J F; Abbott, R P
2009-07-10
LLNL is developing the nuclear fusion based Laser Inertial Fusion Energy (LIFE) power plant concept. The baseline design uses a depleted uranium (DU) fission fuel blanket with a flowing molten salt coolant (flibe) that also breeds the tritium needed to sustain the fusion energy source. Indirect drive targets, similar to those that will be demonstrated on the National Ignition Facility (NIF), are ignited at {approx}13 Hz providing a 500 MW fusion source. The DU is in the form of a uranium oxycarbide kernel in modified TRISO-like fuel particles distributed in a carbon matrix forming 2-cm-diameter pebbles. The thermal power is held at 2000 MW by continuously varying the 6Li enrichment in the coolants. There are many options to be considered in the engine design including target yield, U-to-C ratio in the fuel, fission blanket thickness, etc. Here we report results of design variations and compare them in terms of various figures of merit such as time to reach a desired burnup, full-power years of operation, time and maximum burnup at power ramp down and the overall balance of plant utilization.
1989-03-01
Th usr a toente aninteer a thca sms b esta 1 Fp-ocsing 2. Enter P1 values, lwgt, ldig - > 9 Table I give us proper values. Table 1. PARAMETER TABLE...necessary and identify by block number) In this thesis a control systems analysis package is developed using parameter plane methods. It is an interactive...designer is able to choose values of the parameters which provide a good compromise between cost and dynamic behavior. 20 Distribution Availability of
Geoengineering design parameters workshop
St. John, C.M. and Associates, Grand Junction, CO ); Kim, Kunsoo . Rockwell Hanford Operations)
1985-12-12
A one-day workshop on the subject of the geotechnical design parameters, in situ stress and rock mass strength, for a nuclear waste repository in basalt was held in Rapid City, South Dakota, on June 25, 1989. A panel comprised of five widely recognized experts in the field of rock mechanics, met to discuss the state of stress at the Hanford Site and the strength of a basalt rock mass. This report summarizes the discussions that took place and presents a set of final position statements developed collaboratively by the panel and the workshop moderator. The report concludes with a set of specific recommendations for future actions considered necessary to adequately define the in situ stress and the rock mass strength at the Hanford Site and to document the position of the Basalt Waste Isolation Project in respect to these two critical design parameters.
Jaciw, Andrew P; Lin, Li; Ma, Boya
2016-10-18
Prior research has investigated design parameters for assessing average program impacts on achievement outcomes with cluster randomized trials (CRTs). Less is known about parameters important for assessing differential impacts. This article develops a statistical framework for designing CRTs to assess differences in impact among student subgroups and presents initial estimates of critical parameters. Effect sizes and minimum detectable effect sizes for average and differential impacts are calculated before and after conditioning on effects of covariates using results from several CRTs. Relative sensitivities to detect average and differential impacts are also examined. Student outcomes from six CRTs are analyzed. Achievement in math, science, reading, and writing. The ratio of between-cluster variation in the slope of the moderator divided by total variance-the "moderator gap variance ratio"-is important for designing studies to detect differences in impact between student subgroups. This quantity is the analogue of the intraclass correlation coefficient. Typical values were .02 for gender and .04 for socioeconomic status. For studies considered, in many cases estimates of differential impact were larger than of average impact, and after conditioning on effects of covariates, similar power was achieved for detecting average and differential impacts of the same size. Measuring differential impacts is important for addressing questions of equity, generalizability, and guiding interpretation of subgroup impact findings. Adequate power for doing this is in some cases reachable with CRTs designed to measure average impacts. Continuing collection of parameters for assessing differential impacts is the next step. © The Author(s) 2016.
Wagner, B.J.; Harvey, J.W.
1997-01-01
Tracer experiments are valuable tools for analyzing the transport characteristics of streams and their interactions with shallow groundwater. The focus of this work is the design of tracer studies in high-gradient stream systems subject to advection, dispersion, groundwater inflow, and exchange between the active channel and zones in surface or subsurface water where flow is stagnant or slow moving. We present a methodology for (1) evaluating and comparing alternative stream tracer experiment designs and (2) identifying those combinations of stream transport properties that pose limitations to parameter estimation and therefore a challenge to tracer test design. The methodology uses the concept of global parameter uncertainty analysis, which couples solute transport simulation with parameter uncertainty analysis in a Monte Carlo framework. Two general conclusions resulted from this work. First, the solute injection and sampling strategy has an important effect on the reliability of transport parameter estimates. We found that constant injection with sampling through concentration rise, plateau, and fall provided considerably more reliable parameter estimates than a pulse injection across the spectrum of transport scenarios likely encountered in high-gradient streams. Second, for a given tracer test design, the uncertainties in mass transfer and storage-zone parameter estimates are strongly dependent on the experimental Damkohler number, DaI, which is a dimensionless combination of the rates of exchange between the stream and storage zones, the stream-water velocity, and the stream reach length of the experiment. Parameter uncertainties are lowest at DaI values on the order of 1.0. When DaI values are much less than 1.0 (owing to high velocity, long exchange timescale, and/or short reach length), parameter uncertainties are high because only a small amount of tracer interacts with storage zones in the reach. For the opposite conditions (DaI >> 1.0), solute exchange
Jet pumps for thermoacoustic applications: Design guidelines based on a numerical parameter study.
Oosterhuis, Joris P; Bühler, Simon; Wilcox, Douglas; van der Meer, Theo H
2015-10-01
The oscillatory flow through tapered cylindrical tube sections (jet pumps) is characterized by a numerical parameter study. The shape of a jet pump results in asymmetric hydrodynamic end effects which cause a time-averaged pressure drop to occur under oscillatory flow conditions. Hence, jet pumps are used as streaming suppressors in closed-loop thermoacoustic devices. A two-dimensional axisymmetric computational fluid dynamics model is used to calculate the performance of a large number of conical jet pump geometries in terms of time-averaged pressure drop and acoustic power dissipation. The investigated geometrical parameters include the jet pump length, taper angle, waist diameter, and waist curvature. In correspondence with previous work, four flow regimes are observed which characterize the jet pump performance and dimensionless parameters are introduced to scale the performance of the various jet pump geometries. The simulation results are compared to an existing quasi-steady theory and it is shown that this theory is only applicable in a small operation region. Based on the scaling parameters, an optimum operation region is defined and design guidelines are proposed which can be directly used for future jet pump design.
ERIC Educational Resources Information Center
Westine, Carl; Spybrook, Jessaca
2013-01-01
The capacity of the field to conduct power analyses for group randomized trials (GRTs) of educational interventions has improved over the past decade (Authors, 2009). However, a power analysis depends on estimates of design parameters. Hence it is critical to build the empirical base of design parameters for GRTs across a variety of outcomes and…
Dosimetric parameters of the new design (103)Pd brachytherapy source based on Monte Carlo study.
Saidi, Pooneh; Sadeghi, Mahdi; Shirazi, Alireza; Tenreiro, Claudio
2012-01-01
In this study version 5 of the MCNP photon transport simulation was used to calculate the dosimetric parameters for new palladium brachytherapy source design following AAPM Task Group No. 43U1 report. The internal source components include four resin beads of 0.6 mm diameters with (103)Pd uniformly absorbed inside and one cylindrical copper marker with 1.5 mm length. The resin beads and marker are then encapsulated within 0.8 mm in diameter and 4.5 mm long cylindrical capsule of titanium. The dose rate constant, Λ, line and point-source radial dose function, g(L)(r) and g(P)(r), and the anisotropy function, F(r,θ) of the IR01-(103)Pd seed have been calculated at distances from 0.25 to 5 cm. All the results are in good agreement with previously published thermoluminescence-dosimeter measured values [3] for the source. The dosimetric parameters calculated in this work showed that in dosimetry point of view, the IR01-(103)Pd seed is suitable for use in brachytherapy of prostate cancer.
Controller design and parameter identifiability studies for a large space antenna
NASA Technical Reports Server (NTRS)
Joshi, S. M.
1985-01-01
The problem of control systems synthesis and parameter identifiability are considered for a large, space-based antenna. Two methods are considered for control system synthesis, the first of which uses torque actuators and collocated attitude and rate sensors, and the second method is based on the linear-quadratic-Gaussian (LQG) control theory. The predicted performance obtained by computing variances of pointing, surface and feed misalignment errors in the presence of sensor noise indicates that the LQG-based controller yields superior results. Since controller design requires the knowledge of the system parameters, the identifiability of the structural parameters is investigated by obtaining Cramer-Rao lower bounds. The modal frequencies are found to have the best identifiability, followed by damping ratios, and mode-slopes.
Reeves, Gloria M; Keeton, Courtney; Correll, Christoph U; Johnson, Jacqueline L; Hamer, Robert M; Sikich, Linmarie; Hazzard, Lindsey; Alderman, Cheryl; Scheer, Abigail; Mabe, Micah; Kapoor, Sandeep; Sheridan, Eva; Borner, Irmgard; Bussell, Kristin; Pirmohamed, Sara; Bethea, Terrence C; Chekuri, Raja; Gottfried, Rhoda; Reinblatt, Shauna P; Santana, Erin; Riddle, Mark A
2013-08-15
Youth with serious mental illness may experience improved psychiatric stability with second generation antipsychotic (SGA) medication treatment, but unfortunately may also experience unhealthy weight gain adverse events. Research on weight loss strategies for youth who require ongoing antipsychotic treatment is quite limited. The purpose of this paper is to present the design, methods, and rationale of the Improving Metabolic Parameters in Antipsychotic Child Treatment (IMPACT) study, a federally funded, randomized trial comparing two pharmacologic strategies against a control condition to manage SGA-related weight gain. The design and methodology considerations of the IMPACT trial are described and embedded in a description of health risks associated with antipsychotic-related weight gain and the limitations of currently available research. The IMPACT study is a 4-site, six month, randomized, open-label, clinical trial of overweight/obese youth ages 8-19 years with pediatric schizophrenia-spectrum and bipolar-spectrum disorders, psychotic or non-psychotic major depressive disorder, or irritability associated with autistic disorder. Youth who have experienced clinically significant weight gain during antipsychotic treatment in the past 3 years are randomized to either (1) switch antipsychotic plus healthy lifestyle education (HLE); (2) add metformin plus HLE; or (3) HLE with no medication change. The primary aim is to compare weight change (body mass index z-scores) for each pharmacologic intervention with the control condition. Key secondary assessments include percentage body fat, insulin resistance, lipid profile, psychiatric symptom stability (monitored independently by the pharmacotherapist and a blinded evaluator), and all-cause and specific cause discontinuation. This study is ongoing, and the targeted sample size is 132 youth. Antipsychotic-related weight gain is an important public health issue for youth requiring ongoing antipsychotic treatment to
2013-01-01
Background Youth with serious mental illness may experience improved psychiatric stability with second generation antipsychotic (SGA) medication treatment, but unfortunately may also experience unhealthy weight gain adverse events. Research on weight loss strategies for youth who require ongoing antipsychotic treatment is quite limited. The purpose of this paper is to present the design, methods, and rationale of the Improving Metabolic Parameters in Antipsychotic Child Treatment (IMPACT) study, a federally funded, randomized trial comparing two pharmacologic strategies against a control condition to manage SGA-related weight gain. Methods The design and methodology considerations of the IMPACT trial are described and embedded in a description of health risks associated with antipsychotic-related weight gain and the limitations of currently available research. Results The IMPACT study is a 4-site, six month, randomized, open-label, clinical trial of overweight/obese youth ages 8–19 years with pediatric schizophrenia-spectrum and bipolar-spectrum disorders, psychotic or non-psychotic major depressive disorder, or irritability associated with autistic disorder. Youth who have experienced clinically significant weight gain during antipsychotic treatment in the past 3 years are randomized to either (1) switch antipsychotic plus healthy lifestyle education (HLE); (2) add metformin plus HLE; or (3) HLE with no medication change. The primary aim is to compare weight change (body mass index z-scores) for each pharmacologic intervention with the control condition. Key secondary assessments include percentage body fat, insulin resistance, lipid profile, psychiatric symptom stability (monitored independently by the pharmacotherapist and a blinded evaluator), and all-cause and specific cause discontinuation. This study is ongoing, and the targeted sample size is 132 youth. Conclusion Antipsychotic-related weight gain is an important public health issue for youth requiring
NASA Astrophysics Data System (ADS)
Zhu, Jun; Wu, Peng; Wu, Qiang; Ding, Hua; Li, Xin; Sun, Changjiang
2007-03-01
As the semiconductor fabrication groundrule has reached the 32nm node, in general there are several possible approaches for the photolithography solution such as the double exposure with 1.35 NA immersion, the high refractive index immersion, the extremely ultra violet (EUV) lithography, nanoimprint lithography etc. Among the four, the easiest approach seems to be the double exposure method at an effective numerical aperture (NA) of 1.35. However, there are still challenges in the design and optimization of the process, such as, the use of appropriate illumination condition, the choice of a good photoresist, and the design of an optical proximity correction (OPC) strategy. Besides these considerations, there is a question as whether we really need the double etch process. To study the double exposure mechanism, we have used a 248 nm deep-UV exposure tool and several well chosen photoresist (one is for Space application and the other is for Line application) to study the photo performance parameters in the merge of two photo exposures. At a numerical aperture (NA) around 0.7, the minimum groundrule we can achieve is the one for a 75 nm logic process with minimum pitch around 220 nm. One approach will be that the features with pitches wider than 440 nm are completed in a single exposure, which includes various isolated lines and spaces, line and space ends, two-dimensional structures, etc. This strategy essentially puts the single exposure pattern under the 0.18 um logic like pitches where mild conventional illumination can produce a balanced performance. Under typical illumination conditions, the photolithographic process under 0.18 um like ground rule is well understood and the optical proximity correction is not complicated. The remaining issues are in the dense pitches, where the double exposure kicks in. We have demonstrated that the double exposure with single development can achieve a process window large enough for a 75 nm logic like process and the OPC
Study of design parameters affecting the motion of DNA for nanoinjection
NASA Astrophysics Data System (ADS)
David, Regis A.; Jensen, Brian D.; Black, Justin L.; Burnett, Sandra H.; Howell, Larry L.
2012-05-01
This paper reports the effects of various parameters on the attraction and repulsion of DNA to and from a silicon lance. An understanding of DNA motion is crucial for a new approach to insert DNA, or other foreign microscopic matter, into a living cell. The approach, called nanoinjection, uses electrical forces to attract and repel the desired substance to a micromachined lance designed to pierce the cell membranes. We have developed mathematical models to predict the trajectory of DNA. The mathematical model allows investigation of the attraction/repulsion process by varying specific parameters. We find that the ground electrode placement, lance orientation and lance penetration significantly affect attraction or repulsion efficiency, while the gap, lance direction, lance tip width, lance tip half-angle and lance tip height do not.
Banerjee, Rupak K; Peelukhana, Srikara V; Goswami, Ishan
2014-02-07
The decision to perform intervention on a patient with coronary stenosis is often based on functional diagnostic parameters obtained from pressure and flow measurements using sensor-tipped guidewire at maximal vasodilation (hyperemia). Recently, a rapid exchange Monorail Pressure Sensor catheter of 0.022″ diameter (MPS22), with pressure sensor at distal end has been developed for improved assessment of stenosis severity. The hollow shaft of the MPS22 is designed to slide over any standard 0.014″ guidewire (G14). Hence, influence of MPS22 diameter on coronary diagnostic parameters needs investigation. An in vitro experiment was conducted to replicate physiologic flows in three representative area stenosis (AS): mild (64% AS), intermediate (80% AS), and severe (90% AS), for two arterial diameters, 3mm (N2; more common) and 2.5mm (N1). Influence of MPS22 on diagnostic parameters: fractional flow reserve (FFR) and pressure drop coefficient (CDP) was evaluated both at hyperemic and basal conditions, while comparing it with G14. The FFR values decreased for the MPS22 in comparison to G14, (Mild: 0.87 vs 0.88, Intermediate: 0.68 vs 0.73, Severe: 0.48 vs 0.56) and CDP values increased (Mild: 16 vs 14, Intermediate: 75 vs 56, Severe: 370 vs 182) for N2. Similar trend was observed in the case of N1. The FFR values were found to be well above (mild) and below (intermediate and severe) the diagnostic cut-off of 0.75. Therefore, MPS22 catheter can be used as a possible alternative to G14. Further, irrespective of the MPS22 or G14, basal FFR (FFRb) had overlapping ranges in close proximity for clinically relevant mild and intermediate stenoses that will lead to diagnostic uncertainty under both N1 and N2. However, CDPb had distinct ranges for different stenosis severities and could be a potential diagnostic parameter under basal conditions.
NASA Technical Reports Server (NTRS)
Prasthofer, W. P.
1974-01-01
The key to optimization of design where there are a large number of variables, all of which may not be known precisely, lies in the mathematical tool of dynamic programming developed by Bellman. This methodology can lead to optimized solutions to the design of critical systems in a minimum amount of time, even when there are a great number of acceptable configurations to be considered. To demonstrate the usefulness of dynamic programming, an analytical method is developed for evaluating the relationship among existing numerous connector designs to find the optimum configuration. The data utilized in the study were generated from 900 flanges designed for six subsystems of the S-1B stage of the Saturn 1B space carrier vehicle.
Structural Design Parameters for Germanium
NASA Technical Reports Server (NTRS)
Salem, Jon; Rogers, Richard; Baker, Eric
2017-01-01
The fracture toughness and slow crack growth parameters of germanium supplied as single crystal beams and coarse grain disks were measured. Although germanium is anisotropic (A* 1.7), it is not as anisotropic as SiC, NiAl, or Cu. Thus the fracture toughness was similar on the 100, 110, and 111 planes, however, measurements associated with randomly oriented grinding cracks were 6 to 30 higher. Crack extension in ring loaded disks occurred on the 111 planes due to both the lower fracture energy and the higher stresses on stiff 111 planes. Germanium exhibits a Weibull scale effect, but does not exhibit significant slow crack growth in distilled water. (n 100), implying that design for quasi static loading can be performed with scaled strength statistics. Practical values for engineering design are a fracture toughness of 0.69 0.02 MPam (megapascals per square root meter) and a Weibull modulus of m 6 2. For well ground and reasonable handled coupons, average fracture strength should be greater than 40 megapascals. Aggregate, polycrystalline elastic constants are Epoly 131 gigapascals, vpoly 0.22.
Design Parameters in Multimodal Games for Rehabilitation
Basteris, Angelo; Amirabdollahian, Farshid
2014-01-01
Abstract Objectives: The repetitive and sometimes mundane nature of conventional rehabilitation therapy provides an ideal opportunity for development of interactive and challenging therapeutic games that have the potential to engage and motivate the players. Certain game design parameters that may encourage patients to actively participate by making the games more enjoyable have been identified. In this article, we describe a formative study in which we designed and evaluated some of these parameters with healthy subjects. Materials and Methods: The “operant conditioning” and “scoring” design parameters were incorporated in a remake of a classic labyrinth game, “Marble Maze.” A group of participants (n=37) played the game twice: Once in the control condition without both modalities and then with either one of the parameters or with both. Measures of game duration and number of fails in the game were recorded along with survey questionnaires to measure player perceptions of intrinsic motivation on the game. Results: Longer playtimes, higher levels of interest/enjoyment, and effort to play the game were recorded with the introduction of these parameters. Conclusions: This study provides an understanding on how game design parameters can be used to motivate and encourage people to play longer. With these positive results, future aims are to test the parameters with stroke patients, providing much clearer insight as to what influences these parameters have on patients undergoing therapy. The ultimate goal is to utilize game design in order to maintain longer therapeutic interaction between a patient and his or her therapy medium. PMID:24761328
NASA Astrophysics Data System (ADS)
Raji, M. A.; Schug, K. A.
2009-01-01
Full factorial experimental design technique was used to study the main effects and the interaction effects between instrumental parameters in two mass spectrometers equipped with conventional electrospray ion sources (Thermo LCQ Deca XP and Shimadzu LCMS 2010). Four major parameters (spray voltage, ion transfer capillary temperature, ion transfer capillary voltage, and tube lens voltage) were investigated in both instruments for their contribution to analyte response, leading to a total of 16 experiments performed for each instrument. Significant parameters were identified by plotting the cumulative probability of each treatment against the estimated effects in normal plots. Analysis of variance (ANOVA) was employed to evaluate the statistical significance of the effects of the parameters on ESI-MS analyte response. The results reveal a number of important interactions in addition to the main effects for each instrument. In all the experiments performed, the tube lens voltage (or Q-array dc voltage in LCMS 2010) was found to have significant effects on analyte response in both instruments. The tube lens voltage was also found to interact with the capillary temperature in the case of the LCQ Deca XP and with the spray voltage in the case of the LCMS 2010. The results of these experiments provide important considerations in the instrumental optimization of ionization response for ESI-MS analysis.
Balloon Thermal Model Design Parameters and Sensitivities
NASA Technical Reports Server (NTRS)
Ferguson, Douglas
2017-01-01
This presentation describes the thought process for determining balloon thermal model design parameters, including environmental parameters taken form NASA's top-of-atmosphere (TOA) database, and shows the sensitivity of an example model's key temperature results to those input parameters.
Han, Kyunghwa; Song, Kijun; Choi, Byoung Wook
2016-01-01
Clinical prediction models are developed to calculate estimates of the probability of the presence/occurrence or future course of a particular prognostic or diagnostic outcome from multiple clinical or non-clinical parameters. Radiologic imaging techniques are being developed for accurate detection and early diagnosis of disease, which will eventually affect patient outcomes. Hence, results obtained by radiological means, especially diagnostic imaging, are frequently incorporated into a clinical prediction model as important predictive parameters, and the performance of the prediction model may improve in both diagnostic and prognostic settings. This article explains in a conceptual manner the overall process of developing and validating a clinical prediction model involving radiological parameters in relation to the study design and statistical methods. Collection of a raw dataset; selection of an appropriate statistical model; predictor selection; evaluation of model performance using a calibration plot, Hosmer-Lemeshow test and c-index; internal and external validation; comparison of different models using c-index, net reclassification improvement, and integrated discrimination improvement; and a method to create an easy-to-use prediction score system will be addressed. This article may serve as a practical methodological reference for clinical researchers.
Han, Kyunghwa; Choi, Byoung Wook
2016-01-01
Clinical prediction models are developed to calculate estimates of the probability of the presence/occurrence or future course of a particular prognostic or diagnostic outcome from multiple clinical or non-clinical parameters. Radiologic imaging techniques are being developed for accurate detection and early diagnosis of disease, which will eventually affect patient outcomes. Hence, results obtained by radiological means, especially diagnostic imaging, are frequently incorporated into a clinical prediction model as important predictive parameters, and the performance of the prediction model may improve in both diagnostic and prognostic settings. This article explains in a conceptual manner the overall process of developing and validating a clinical prediction model involving radiological parameters in relation to the study design and statistical methods. Collection of a raw dataset; selection of an appropriate statistical model; predictor selection; evaluation of model performance using a calibration plot, Hosmer-Lemeshow test and c-index; internal and external validation; comparison of different models using c-index, net reclassification improvement, and integrated discrimination improvement; and a method to create an easy-to-use prediction score system will be addressed. This article may serve as a practical methodological reference for clinical researchers. PMID:27134523
NASA Astrophysics Data System (ADS)
Zhang, Zongliang; Meng, Jiale; Guo, Lei; Guo, Zhancheng
2015-09-01
Gas distribution plays a significant role in an oxygen blast furnace. The uneven distribution of recycling gas from the shaft tuyere has been shown to affect the heat distribution and energy utilization in an oxygen blast furnace. Therefore, the optimal design and operating parameters beneficial to the gas distribution in an oxygen blast furnace should be determined. In total, three parameters and 22 different conditions in an oxygen blast furnace multifluid model were considered. The gas and heat distributions in an oxygen blast furnace under different conditions were simulated and compared. The study revealed that when the height of shaft tuyere decreased from 7.8 m to 3.8 m, the difference in top gas CO concentration between the center and edge decreased by 11.6%. When the recycling gas temperature increased from 1123 K to 1473 K, the difference in the top gas CO concentration between the center and edge decreased by 3.9%. As the allocation ratio increased from 0.90 to 1.94, the difference in the top gas CO concentration between the center and edge decreased by 3.0%. Considering both gas and heat distributions, a shaft tuyere height of 3.8 m to 4.8 m, a recycling gas temperature of 1473 K and an allocation ratio of 1.94 are recommended in practice under the conditions of this study.
Design parameters and source terms: Volume 1, Design parameters: Revision 0
Not Available
1987-10-01
The Design Parameters and Source Terms Document was prepared in accordance with DOE request and to provide data for the environmental impact study to be performed in the future for the Deaf Smith County, Texas site for a nuclear waste repository in salt. This document updates a previous unpublished report by Stearns Catalytic Corporation (SCC), entitled ''Design Parameters and Source Terms for a Two-Phase Repository in Salt,'' 1985, to the level of the Site Characterization Plan - Conceptual Design Report. The previous unpublished SCC Study identifies the data needs for the Environmental Assessment effort for seven possible Salt Repository sites.
Aerodynamics as a subway design parameter
NASA Technical Reports Server (NTRS)
Kurtz, D. W.
1976-01-01
A parametric sensitivity study has been performed on the system operational energy requirement in order to guide subway design strategy. Aerodynamics can play a dominant or trivial role, depending upon the system characteristics. Optimization of the aerodynamic parameters may not minimize the total operational energy. Isolation of the station box from the tunnel and reduction of the inertial power requirements pay the largest dividends in terms of the operational energy requirement.
Star Tracker/Mapper: System Design Parameters
1974-09-01
AD-A008 554 STAR TRACKER/MAPPER: SYSTEM’DESIGN PARAMETERS F. W. Schenkel Johns Hopkins University Prepared for: Naval Plant Representative Office...APLIJHU TG 1256 4. TITLE (andSubritle) 5. TYPE OF REPORT & PERIOD COVERED Star Tracker/Mapper: System Design Parameters 6. PERFORMING ORG. REPORT...identify by block number) Design parameters Star tracker/mapper Optical sensors Optical trackers Spectral characteristics 20. ABSTRACT (Continue on
Coffey, Todd
2015-01-01
Cell-based potency assays play an important role in the characterization of biopharmaceuticals but they can be challenging to develop in part because of greater inherent variability than other analytical methods. Our objective is to select concentrations on a dose-response curve that will enhance assay robustness. We apply the maximin D-optimal design concept to the four-parameter logistic (4 PL) model and then derive and compute the maximin D-optimal design for a challenging bioassay using curves representative of assay variation. The selected concentration points from this 'best worst case' design adequately fit a variety of 4 PL shapes and demonstrate improved robustness.
Design parameters for rotary extrusion macerators
Nelson, F.W.; Barrington, G.P.; Straub, R.J.; Bruhn, H.D.
1981-01-01
Design parameters for an extrusion macerator for plant juice protein extraction are discussed. Forces developed can be predicted for various machine configurations, throughputs, speeds, and extrusion pressures from a simple nomogram. 5 refs.
NASA Technical Reports Server (NTRS)
Torres-Pomales, Wilfredo
2015-01-01
This report documents a case study on the application of Reliability Engineering techniques to achieve an optimal balance between performance and robustness by tuning the functional parameters of a complex non-linear control system. For complex systems with intricate and non-linear patterns of interaction between system components, analytical derivation of a mathematical model of system performance and robustness in terms of functional parameters may not be feasible or cost-effective. The demonstrated approach is simple, structured, effective, repeatable, and cost and time efficient. This general approach is suitable for a wide range of systems.
Design parameters of toroidal and bobbin magnetics
NASA Technical Reports Server (NTRS)
Mclyman, W. T.
1973-01-01
The adoption by NASA of the metric system for dimensioning to replace the long-used English units imposes a requirement on the U.S. transformer designer to convert from the familiar units to the less familiar metric equivalents. Material is presented to assist in that transition in the field of transformer design and fabrication. The conversion data makes it possible for the designer to obtain a fast and close approximation of significant parameters such as size, weight, and temperature rise. Nomographs are included to provide a close approximation for breadboarding purposes. For greater convenience, derivations of some of the parameters are also presented.
Design parameters and source terms: Volume 1, Design parameters: Revision 0
Not Available
1987-09-01
The Design Parameters and Source Terms Document was prepared in accordance with DOE request and to provide data for the environmental impact study to be performed in the future for the Deaf Smith County, Texas site for a nuclear waste repository in salt. This document updates a previous unpublished report to the level of the Site Characterization Plan - Conceptual Design Report, SCP-CDR. The previous unpublished SCC Study identified the data needs for the Environmental Assessment effort for seven possible salt repository sites.
Optimal design criteria - prediction vs. parameter estimation
NASA Astrophysics Data System (ADS)
Waldl, Helmut
2014-05-01
G-optimality is a popular design criterion for optimal prediction, it tries to minimize the kriging variance over the whole design region. A G-optimal design minimizes the maximum variance of all predicted values. If we use kriging methods for prediction it is self-evident to use the kriging variance as a measure of uncertainty for the estimates. Though the computation of the kriging variance and even more the computation of the empirical kriging variance is computationally very costly and finding the maximum kriging variance in high-dimensional regions can be time demanding such that we cannot really find the G-optimal design with nowadays available computer equipment in practice. We cannot always avoid this problem by using space-filling designs because small designs that minimize the empirical kriging variance are often non-space-filling. D-optimality is the design criterion related to parameter estimation. A D-optimal design maximizes the determinant of the information matrix of the estimates. D-optimality in terms of trend parameter estimation and D-optimality in terms of covariance parameter estimation yield basically different designs. The Pareto frontier of these two competing determinant criteria corresponds with designs that perform well under both criteria. Under certain conditions searching the G-optimal design on the above Pareto frontier yields almost as good results as searching the G-optimal design in the whole design region. In doing so the maximum of the empirical kriging variance has to be computed only a few times though. The method is demonstrated by means of a computer simulation experiment based on data provided by the Belgian institute Management Unit of the North Sea Mathematical Models (MUMM) that describe the evolution of inorganic and organic carbon and nutrients, phytoplankton, bacteria and zooplankton in the Southern Bight of the North Sea.
Cryogenic masers. [frequency stability and design parameters
NASA Technical Reports Server (NTRS)
Berlinsky, A. J.; Hardy, W. N.
1982-01-01
Various factors affecting the frequency stability of hydrogen masers are described and related to maser design parameters. The long-term frequency stability of a hydrogen maser is limited by the mechanical stability of the cavity, and the magnitudes of the wall relaxation, spin exchange, and recombination rates which affect the Q of the line. Magnetic resonance studies of hydrogen atoms at temperatures below 1 K and in containers coated with liquid helium films demonstrated that cryogenic masers may allow substantial improvements in all of these parameters. In particular the thermal expansion coefficients of most materials are negligible at 1 K. Spin exchange broadening is three orders of magnitude smaller at 1 K than at room temperature, and the recombination and wall relaxation rates are negligible at 0.52 K where the frequency shift due to the 4 He-coated walls of the container has a broad minimum as a function of temperature. Other advantages of the helium-cooled maser result from the high purity, homogeneity, and resilence of helium-film-coated walls and the natural compatibility of the apparatus with helium-cooled amplifiers.
Design parameters for wearable optical imagers
NASA Astrophysics Data System (ADS)
Akin, Ata; Kim, Sanghyun; Pourrezaei, Kambiz; Chance, Britton; Nioka, Shoko
2001-06-01
This paper summarizes the design steps that are followed during the development of the portable optical imager for breast cancer screening. The design steps considered the parameters such as total power consumption versus battery weight and size, speed of data acquisition versus cost and complexity of the design (functionality), graphical display versus operating system choice. We have used a single board computer system that uses Windows CE as the real time operating system. This choice was preferred since our graphical display requirements can only be carried out with the CE environment's GUI kernels.
Robust design of configurations and parameters of adaptable products
NASA Astrophysics Data System (ADS)
Zhang, Jian; Chen, Yongliang; Xue, Deyi; Gu, Peihua
2014-03-01
An adaptable product can satisfy different customer requirements by changing its configuration and parameter values during the operation stage. Design of adaptable products aims at reducing the environment impact through replacement of multiple different products with single adaptable ones. Due to the complex architecture, multiple functional requirements, and changes of product configurations and parameter values in operation, impact of uncertainties to the functional performance measures needs to be considered in design of adaptable products. In this paper, a robust design approach is introduced to identify the optimal design configuration and parameters of an adaptable product whose functional performance measures are the least sensitive to uncertainties. An adaptable product in this paper is modeled by both configurations and parameters. At the configuration level, methods to model different product configuration candidates in design and different product configuration states in operation to satisfy design requirements are introduced. At the parameter level, four types of product/operating parameters and relations among these parameters are discussed. A two-level optimization approach is developed to identify the optimal design configuration and its parameter values of the adaptable product. A case study is implemented to illustrate the effectiveness of the newly developed robust adaptable design method.
Lee, K.E.
2002-01-01
This report describes the study design, sampling methods, and summarizes the physical, chemical, and benthic algal data for a component of the multiagency study that was designed to document diurnal water-quality measurements (specific conductance, pH, water temperature, and dissolved oxygen), benthic algal community composition and chlorophyll-a content, and primary productivity at 12 stream sites on 6 streams in Minnesota during August 2000. Specific conductance, pH, water temperature, dissolved oxygen concentrations and percent dissolved oxygen saturation measurements were made with submersible data recorders at 30 minute intervals for a period of 3-6 days during August 2000. Benthic algae collected from wood and rock substrate were identified and enumerated. Biovolume (volume of algal cells per unit area), density (number of cells per unit area), and chlorophyll-a content from benthic algae were determined. These data can be used as part of the multiagency study to develop an understanding of the relations among nutrient concentrations, algal abundance, algal community composition, and primary production and respiration processes in rivers of differing ecoregions in Minnesota.
Novel parameter-based flexure bearing design method
NASA Astrophysics Data System (ADS)
Amoedo, Simon; Thebaud, Edouard; Gschwendtner, Michael; White, David
2016-06-01
A parameter study was carried out on the design variables of a flexure bearing to be used in a Stirling engine with a fixed axial displacement and a fixed outer diameter. A design method was developed in order to assist identification of the optimum bearing configuration. This was achieved through a parameter study of the bearing carried out with ANSYS®. The parameters varied were the number and the width of the arms, the thickness of the bearing, the eccentricity, the size of the starting and ending holes, and the turn angle of the spiral. Comparison was made between the different designs in terms of axial and radial stiffness, the natural frequency, and the maximum induced stresses. Moreover, the Finite Element Analysis (FEA) was compared to theoretical results for a given design. The results led to a graphical design method which assists the selection of flexure bearing geometrical parameters based on pre-determined geometric and material constraints.
Design sensitivity analysis using EAL. Part 2: Shape design parameters
NASA Technical Reports Server (NTRS)
Dopker, B.; Choi, Kyung K.
1986-01-01
A numerical implementation of shape design sensitivity analysis of built-up structures is presented, using the versatility and convenience of an existing finite element structural analysis code and its data base management system. This report is a continuation of a previous report on conventional design parameters. The finite element code used in the implementation presented is the Engineering Analysis Language (EAL), which is based on a hybrid analysis method. It has been shown that shape design sensitivity computations can be carried out using the database management system of EAL, without writing a separate program and a separate data base. The material derivative concept of continuum mechanics and an adjoint variable method of design sensitivity analysis are used to derive shape design sensitivity information of structural performances. A domain method of shape design sensitivity analysis and a design component method are used. Displacement and stress functionals are considered as performance criteria.
Design parameters for rotating cylindrical filtration
NASA Technical Reports Server (NTRS)
Schwille, John A.; Mitra, Deepanjan; Lueptow, Richard M.
2002-01-01
Rotating cylindrical filtration displays significantly reduced plugging of filter pores and build-up of a cake layer, but the number and range of parameters that can be adjusted complicates the design of these devices. Twelve individual parameters were investigated experimentally by measuring the build-up of particles on the rotating cylindrical filter after a fixed time of operation. The build-up of particles on the filter depends on the rotational speed, the radial filtrate flow, the particle size and the gap width. Other parameters, such as suspension concentration and total flow rate are less important. Of the four mechanisms present in rotating filters to reduce pore plugging and cake build-up, axial shear, rotational shear, centrifugal sedimentation and vortical motion, the evidence suggests rotational shear is the dominant mechanism, although the other mechanisms still play minor roles. The ratio of the shear force acting parallel to the filter surface on a particle to the Stokes drag acting normal to the filter surface on the particle due to the difference between particle motion and filtrate flow can be used as a non-dimensional parameter that predicts the degree of particle build-up on the filter surface for a wide variety of filtration conditions. c2002 Elsevier Science B.V. All rights reserved.
Design parameters for rotating cylindrical filtration
NASA Technical Reports Server (NTRS)
Schwille, John A.; Mitra, Deepanjan; Lueptow, Richard M.
2002-01-01
Rotating cylindrical filtration displays significantly reduced plugging of filter pores and build-up of a cake layer, but the number and range of parameters that can be adjusted complicates the design of these devices. Twelve individual parameters were investigated experimentally by measuring the build-up of particles on the rotating cylindrical filter after a fixed time of operation. The build-up of particles on the filter depends on the rotational speed, the radial filtrate flow, the particle size and the gap width. Other parameters, such as suspension concentration and total flow rate are less important. Of the four mechanisms present in rotating filters to reduce pore plugging and cake build-up, axial shear, rotational shear, centrifugal sedimentation and vortical motion, the evidence suggests rotational shear is the dominant mechanism, although the other mechanisms still play minor roles. The ratio of the shear force acting parallel to the filter surface on a particle to the Stokes drag acting normal to the filter surface on the particle due to the difference between particle motion and filtrate flow can be used as a non-dimensional parameter that predicts the degree of particle build-up on the filter surface for a wide variety of filtration conditions. c2002 Elsevier Science B.V. All rights reserved.
Krüger, S.; Grupp, T. M.; Duda, G. N.; Blömer, W.; Rohlmann, A.
2010-01-01
As an alternative treatment for chronic back pain due to disc degeneration motion preserving techniques such as posterior dynamic stabilization (PDS) has been clinically introduced, with the intention to alter the load transfer and the kinematics at the affected level to delay degeneration. However, up to the present, it remains unclear when a PDS is clinically indicated and how the ideal PDS mechanism should be designed to achieve this goal. Therefore, the objective of this study was to compare different PDS devices against rigid fixation to investigate the biomechanical impact of PDS design on stabilization and load transfer in the treated and adjacent cranial segment. Six human lumbar spine specimens (L3–L5) were tested in a spine loading apparatus. In vitro flexibility testing was performed by applying pure bending moments of 7.5 Nm without and with additional preload of 400 N in the three principal motion planes. Four PDS devices, “DYN” (Dynesys®, Zimmer GmbH, Switzerland), “DSS™” (Paradigm Spine, Wurmlingen, Germany), and two prototypes of dynamic rods, “LSC” with a leaf spring, and “STC” with a spring tube (Aesculap AG, Tuttlingen, Germany), were tested in comparison to a rigid fixation device S4 (Aesculap AG, Tuttlingen, Germany) “RIG”, to the native situation “NAT” and to a defect situation “DEF” of the specimens. The instrumented level was L4–L5. The tested PDS devices comprising a stiffness range for axial stiffness of 10 N/mm to 230 N/mm and for bending stiffness of 3 N/mm to 15 N/mm. Range of motion (ROM), neutral zone (NZ), and intradiscal pressure (IDP) were analyzed for all instrumentation steps and load cases of the instrumented and non-instrumented level. In flexion, extension, and lateral bending, all systems, except STC, showed a significant reduction of ROM and NZ compared to the native situation (p < 0.05). Furthermore, we found no significant difference between DYN and RIG (p > 0.1). In axial
Sequential ensemble-based optimal design for parameter estimation
NASA Astrophysics Data System (ADS)
Man, Jun; Zhang, Jiangjiang; Li, Weixuan; Zeng, Lingzao; Wu, Laosheng
2016-10-01
The ensemble Kalman filter (EnKF) has been widely used in parameter estimation for hydrological models. The focus of most previous studies was to develop more efficient analysis (estimation) algorithms. On the other hand, it is intuitively understandable that a well-designed sampling (data-collection) strategy should provide more informative measurements and subsequently improve the parameter estimation. In this work, a Sequential Ensemble-based Optimal Design (SEOD) method, coupled with EnKF, information theory and sequential optimal design, is proposed to improve the performance of parameter estimation. Based on the first-order and second-order statistics, different information metrics including the Shannon entropy difference (SD), degrees of freedom for signal (DFS) and relative entropy (RE) are used to design the optimal sampling strategy, respectively. The effectiveness of the proposed method is illustrated by synthetic one-dimensional and two-dimensional unsaturated flow case studies. It is shown that the designed sampling strategies can provide more accurate parameter estimation and state prediction compared with conventional sampling strategies. Optimal sampling designs based on various information metrics perform similarly in our cases. The effect of ensemble size on the optimal design is also investigated. Overall, larger ensemble size improves the parameter estimation and convergence of optimal sampling strategy. Although the proposed method is applied to unsaturated flow problems in this study, it can be equally applied in any other hydrological problems.
Design sensitivity analysis using EAL. Part 1: Conventional design parameters
NASA Technical Reports Server (NTRS)
Dopker, B.; Choi, Kyung K.; Lee, J.
1986-01-01
A numerical implementation of design sensitivity analysis of builtup structures is presented, using the versatility and convenience of an existing finite element structural analysis code and its database management system. The finite element code used in the implemenatation presented is the Engineering Analysis Language (EAL), which is based on a hybrid method of analysis. It was shown that design sensitivity computations can be carried out using the database management system of EAL, without writing a separate program and a separate database. Conventional (sizing) design parameters such as cross-sectional area of beams or thickness of plates and plane elastic solid components are considered. Compliance, displacement, and stress functionals are considered as performance criteria. The method presented is being extended to implement shape design sensitivity analysis using a domain method and a design component method.
Design parameters and source terms: Volume 3, Source terms
Not Available
1987-10-01
The Design Parameters and Source Terms Document was prepared in accordance with DOE request and to provide data for the environmental impact study to be performed in the future for the Deaf Smith County, Texas site for a nuclear waste repository in salt. This document updates a previous unpublished report by Stearns Catalytic Corporation (SCC), entitled ''Design Parameters and Source Terms for a Two-Phase Repository in Salt,'' 1985, to the level of the Site Characterization Plan - Conceptual Design Report. The previous unpublished SCC Study identifies the data needs for the Environmental Assessment effort for seven possible Salt Repository sites. 11 refs., 9 tabs.
Blondet, Francisco Peirano; Vincent, Thierry; Guibal, Eric
2008-07-01
The strong affinity of chitosan for metal ions and more specifically for precious metals such as palladium and platinum has focused the interest on using this biopolymer as a support for catalytic metals. The manufacturing of hollow chitosan fibers, softly cross-linked with glutaraldehyde, followed by palladium sorption at pH 2 in HCl solutions and further reduction using hydrogen gas, opened the route for the design of a new continuous catalytic system. This material was used for the hydrogenation of nitrotoluene, which was converted into o-toluidine, in methanol solutions. The substrate was circulated inside the lumen of the fiber, while the hydrogen donor (hydrogen gas) was maintained at constant pressure in the outlet compartment of the reactor. Several parameters (substrate concentration, metal content in the fiber, and flow rate) have been tested for their impact on catalytic performance, measured by the turnover frequency (TOF), conversion yield or o-toluidine production, using a surface response methodology for the optimization of the process. Metal content in the fiber revealed a critical parameter; the influence of this parameter was extensively studied through the structural characterization of the fibers using XPS analysis (oxidation state of Pd), X-ray diffraction analysis (size of Pd crystals), TEM analysis (size and distribution of Pd crystals), and diffusion profiles (porosity) in order to correlate catalytic performance to fiber characterization.
Hedberg, E C
2016-06-28
There is an increased focus on randomized trials for proximal behavioral outcomes in early childhood research. However, planning sample sizes for such designs requires extant information on the size of effect, variance decomposition, and effectiveness of covariates. The purpose of this article is to employ a recent large representative sample of early childhood longitudinal study kindergartners to estimate design parameters for use in planning cluster randomized trials. A secondary objective is to compare the results of math and reading with the previous kindergartner cohort of 1999. For each measure, fall-spring gains in effect size units are calculated. In addition, multilevel models are fit to estimate variance components that are used to calculate intraclass correlations (ICCs) and R (2) statistics. The implications of the reported parameters are summarized in tables of required school sample sizes to detect small effects. The outcomes include information about student scores regarding learning behaviors, general behaviors, and academic abilities. Aside from math and reading, there were small gains in these measures from fall to spring, leading to effect sizes between about .1 and .2. In addition, the nonacademic ICCs are smaller than the academic ICCs but are still nontrivial. Use of a pretest covariate is generally effective in reducing the required sample size in power analyses. The ICCs for math and reading are smaller for the current sample compared with the 1999 sample. © The Author(s) 2016.
Optimal Linking Design for Response Model Parameters
ERIC Educational Resources Information Center
Barrett, Michelle D.; van der Linden, Wim J.
2017-01-01
Linking functions adjust for differences between identifiability restrictions used in different instances of the estimation of item response model parameters. These adjustments are necessary when results from those instances are to be compared. As linking functions are derived from estimated item response model parameters, parameter estimation…
NASA Astrophysics Data System (ADS)
Alimin, A. F. Muhammad; Radzi, A. A. Mohd; Sazali, N. A. F.; Hatta, S. F. Wan Muhamad; Soin, N.; Hussin, H.
2017-10-01
Negative-bias temperature instability (NBTI) has become a prominent factor limiting scaling of complementary metal-oxide-semiconductor technology. This work presents a comprehensive simulation study on the effects of critical design parameters of 32-nm advanced-process high- k p-channel metal-oxide-semiconductor field-effect transistors on NBTI. The NBTI mechanism and defects were explored for various geometric and process design parameters over a wide range of values. The NBTI simulation method applied in this work follows the on-the-fly method to capture the mechanisms of fast and slow traps. This work illustrates the dependence of the threshold voltage ( V th) degradation on the stress oxide field and stress temperature as well as investigation of the Arrhenius plot for the devices. The temperature insensitivity during short stress time of 1 ms indicates absence of generated defects and presence of preexisting defects. It is also observed that significant defects are generated in the gate stack subsequent to NBTI. The slope obtained from the V th degradation analysis at 1 ks and 375°C shows that changing the SiO2 interfacial layer thickness affects the V th degradation by 96.16% more than changing the HfO2 thickness and by 80.67% more than changing the metal gate thickness. It is also found that the NBTI effect depends on process design considerations, specifically the boron concentration in the highly doped drain, the metal gate work function, and the halo doping concentration; it was observed that higher boron dose and high metal work function may lead to higher V th degradation. However, the halo doping concentration in the advanced 32-nm structure has an insignificant effect on NBTI.
Statistical Analyses of Femur Parameters for Designing Anatomical Plates.
Wang, Lin; He, Kunjin; Chen, Zhengming
2016-01-01
Femur parameters are key prerequisites for scientifically designing anatomical plates. Meanwhile, individual differences in femurs present a challenge to design well-fitting anatomical plates. Therefore, to design anatomical plates more scientifically, analyses of femur parameters with statistical methods were performed in this study. The specific steps were as follows. First, taking eight anatomical femur parameters as variables, 100 femur samples were classified into three classes with factor analysis and Q-type cluster analysis. Second, based on the mean parameter values of the three classes of femurs, three sizes of average anatomical plates corresponding to the three classes of femurs were designed. Finally, based on Bayes discriminant analysis, a new femur could be assigned to the proper class. Thereafter, the average anatomical plate suitable for that new femur was selected from the three available sizes of plates. Experimental results showed that the classification of femurs was quite reasonable based on the anatomical aspects of the femurs. For instance, three sizes of condylar buttress plates were designed. Meanwhile, 20 new femurs are judged to which classes the femurs belong. Thereafter, suitable condylar buttress plates were determined and selected.
Statistical Analyses of Femur Parameters for Designing Anatomical Plates
2016-01-01
Femur parameters are key prerequisites for scientifically designing anatomical plates. Meanwhile, individual differences in femurs present a challenge to design well-fitting anatomical plates. Therefore, to design anatomical plates more scientifically, analyses of femur parameters with statistical methods were performed in this study. The specific steps were as follows. First, taking eight anatomical femur parameters as variables, 100 femur samples were classified into three classes with factor analysis and Q-type cluster analysis. Second, based on the mean parameter values of the three classes of femurs, three sizes of average anatomical plates corresponding to the three classes of femurs were designed. Finally, based on Bayes discriminant analysis, a new femur could be assigned to the proper class. Thereafter, the average anatomical plate suitable for that new femur was selected from the three available sizes of plates. Experimental results showed that the classification of femurs was quite reasonable based on the anatomical aspects of the femurs. For instance, three sizes of condylar buttress plates were designed. Meanwhile, 20 new femurs are judged to which classes the femurs belong. Thereafter, suitable condylar buttress plates were determined and selected. PMID:28044087
Sun, Tien-Lung; Lee, Chia-Hsuan
2013-01-01
Kinect-based exergames allow players to undertake physical exercise in an interactive manner with visual stimulation. Previous studies focused on investigating physical fitness based on calories or heart rate to ascertain the effectiveness of exergames. However, designing an exergame for specific training purposes, with intensity levels suited to the needs and skills of the players, requires the investigation of motion performance to study player experience. This study investigates how parameters of a Kinect-based exergame, combined with balance training exercises, influence the balance control ability and intensity level the player can tolerate, by analyzing both objective and gameplay-based player experience, and taking enjoyment and difficulty levels into account. The exergame tested required participants to maintain their balance standing on one leg within a posture frame (PF) while a force plate evaluated the player's balance control ability in both static and dynamic gaming modes. The number of collisions with the PF depended on the frame's travel time for static PFs, and the leg-raising rate and angle for dynamic PFs. In terms of center of pressure (COP) metrics, significant impacts were caused by the frame's travel time on MDIST-AP for static PFs, and the leg-raising rate on MDIST-ML and TOTEX for dynamic PFs. The best static PF balance control performance was observed with a larger frame offset by a travel time of 2 seconds, and the worst performance with a smaller frame and a travel time of 1 second. The best dynamic PF performance was with a leg-raising rate of 1 second at a 45-degree angle, while the worst performance was with a rate of 2 seconds at a 90-degree angle. The results demonstrated that different evaluation methods for player experience could result in different findings, making it harder to study the design of those exergames with training purposes based on player experience.
2013-01-01
Kinect-based exergames allow players to undertake physical exercise in an interactive manner with visual stimulation. Previous studies focused on investigating physical fitness based on calories or heart rate to ascertain the effectiveness of exergames. However, designing an exergame for specific training purposes, with intensity levels suited to the needs and skills of the players, requires the investigation of motion performance to study player experience. This study investigates how parameters of a Kinect-based exergame, combined with balance training exercises, influence the balance control ability and intensity level the player can tolerate, by analyzing both objective and gameplay-based player experience, and taking enjoyment and difficulty levels into account. The exergame tested required participants to maintain their balance standing on one leg within a posture frame (PF) while a force plate evaluated the player's balance control ability in both static and dynamic gaming modes. The number of collisions with the PF depended on the frame's travel time for static PFs, and the leg-raising rate and angle for dynamic PFs. In terms of center of pressure (COP) metrics, significant impacts were caused by the frame's travel time on MDIST-AP for static PFs, and the leg-raising rate on MDIST-ML and TOTEX for dynamic PFs. The best static PF balance control performance was observed with a larger frame offset by a travel time of 2 seconds, and the worst performance with a smaller frame and a travel time of 1 second. The best dynamic PF performance was with a leg-raising rate of 1 second at a 45-degree angle, while the worst performance was with a rate of 2 seconds at a 90-degree angle. The results demonstrated that different evaluation methods for player experience could result in different findings, making it harder to study the design of those exergames with training purposes based on player experience. PMID:23922716
Parameter Screening and Optimisation for ILP Using Designed Experiments
NASA Astrophysics Data System (ADS)
Srinivasan, Ashwin; Ramakrishnan, Ganesh
Reports of experiments conducted with an Inductive Logic Programming system rarely describe how specific values of parameters of the system are arrived at when constructing models. Usually, no attempt is made to identify sensitive parameters, and those that are used are often given "factory-supplied" default values, or values obtained from some non-systematic exploratory analysis. The immediate consequence of this is, of course, that it is not clear if better models could have been obtained if some form of parameter selection and optimisation had been performed. Questions follow inevitably on the experiments themselves: specifically, are all algorithms being treated fairly, and is the exploratory phase sufficiently well-defined to allow the experiments to be replicated? In this paper, we investigate the use of parameter selection and optimisation techniques grouped under the study of experimental design. Screening and "response surface" methods determine, in turn, sensitive parameters and good values for these parameters. This combined use of parameter selection and response surface-driven optimisation has a long history of application in industrial engineering, and its role in ILP is investigated using two well-known benchmarks. The results suggest that computational overheads from this preliminary phase are not substantial, and that much can be gained, both on improving system performance and on enabling controlled experimentation, by adopting well-established procedures such as the ones proposed here.
Man, Jun; Zhang, Jiangjiang; Li, Weixuan; Zeng, Lingzao; Wu, Laosheng
2016-10-01
The ensemble Kalman filter (EnKF) has been widely used in parameter estimation for hydrological models. The focus of most previous studies was to develop more efficient analysis (estimation) algorithms. On the other hand, it is intuitively understandable that a well-designed sampling (data-collection) strategy should provide more informative measurements and subsequently improve the parameter estimation. In this work, a Sequential Ensemble-based Optimal Design (SEOD) method, coupled with EnKF, information theory and sequential optimal design, is proposed to improve the performance of parameter estimation. Based on the first-order and second-order statistics, different information metrics including the Shannon entropy difference (SD), degrees of freedom for signal (DFS) and relative entropy (RE) are used to design the optimal sampling strategy, respectively. The effectiveness of the proposed method is illustrated by synthetic one-dimensional and two-dimensional unsaturated flow case studies. It is shown that the designed sampling strategies can provide more accurate parameter estimation and state prediction compared with conventional sampling strategies. Optimal sampling designs based on various information metrics perform similarly in our cases. The effect of ensemble size on the optimal design is also investigated. Overall, larger ensemble size improves the parameter estimation and convergence of optimal sampling strategy. Although the proposed method is applied to unsaturated flow problems in this study, it can be equally applied in any other hydrological problems.
Designing of discrete mechatronic vibrating systems with negative value parameters
NASA Astrophysics Data System (ADS)
Buchacz, Andrzej; Gałęziowski, Damian
2016-10-01
In the paper, the known problem of vibration control, authors expanded for designing of mechatronic discrete systems that contains single or multiply piezoelectric elements connected to external electric networks. Main focus has been given for investigations in relation to damping performance and parameters study, in case of potential practical application. By different configurations of considered mechatronic discrete branched structures with two degrees of freedom, key negative parameters have been identified and investigated in case of vibration control effectiveness. Results have been presented in graphical form of amplitudes and dynamical flexibility functions.
Seismic design parameters - A user guide
Leyendecker, E.V.; Frankel, A.D.; Rukstales, K.S.
2001-01-01
The 1997 NEHRP Recommended Provisions for Seismic Regulations for New Buildings (1997 NEHRP Provisions) introduced seismic design procedure that is based on the explicit use of spectral response acceleration rather than the traditional peak ground acceleration and/or peak ground velocity or zone factors. The spectral response accelerations are obtained from spectral response acceleration maps accompanying the report. Maps are available for the United States and a number of U.S. territories. Since 1997 additional codes and standards have also adopted seismic design approaches based on the same procedure used in the NEHRP Provisions and the accompanying maps. The design documents using the 1997 NEHRP Provisions procedure may be divided into three categories -(1) Design of New Construction, (2) Design and Evaluation of Existing Construction, and (3) Design of Residential Construction. A CD-ROM has been prepared for use in conjunction with the design documents in each of these three categories. The spectral accelerations obtained using the software on the CD are the same as those that would be obtained by using the maps accompanying the design documents. The software has been prepared to operate on a personal computer using a Windows (Microsoft Corporation) operating environment and a point and click type of interface. The user can obtain the spectral acceleration values that would be obtained by use of the maps accompanying the design documents, include site factors appropriate for the Site Class provided by the user, calculate a response spectrum that includes the site factor, and plot a response spectrum. Sites may be located by providing the latitude-longitude or zip code for all areas covered by the maps. All of the maps used in the various documents are also included on the CDROM
Seismic design parameters - A user guide
Leyendecker, E.V.; Frankel, A.D.; Rukstales, K.S.
2001-01-01
The 1997 NEHRP Recommended Provisions for Seismic Regulations for New Buildings (1997 NEHRP Provisions) introduced seismic design procedure that is based on the explicit use of spectral response acceleration rather than the traditional peak ground acceleration and/or peak ground velocity or zone factors. The spectral response accelerations are obtained from spectral response acceleration maps accompanying the report. Maps are available for the United States and a number of U.S. territories. Since 1997 additional codes and standards have also adopted seismic design approaches based on the same procedure used in the NEHRP Provisions and the accompanying maps. The design documents using the 1997 NEHRP Provisions procedure may be divided into three categories -(1) Design of New Construction, (2) Design and Evaluation of Existing Construction, and (3) Design of Residential Construction. A CD-ROM has been prepared for use in conjunction with the design documents in each of these three categories. The spectral accelerations obtained using the software on the CD are the same as those that would be obtained by using the maps accompanying the design documents. The software has been prepared to operate on a personal computer using a Windows (Microsoft Corporation) operating environment and a point and click type of interface. The user can obtain the spectral acceleration values that would be obtained by use of the maps accompanying the design documents, include site factors appropriate for the Site Class provided by the user, calculate a response spectrum that includes the site factor, and plot a response spectrum. Sites may be located by providing the latitude-longitude or zip code for all areas covered by the maps. All of the maps used in the various documents are also included on the CDROM
GRCop-84 Rolling Parameter Study
NASA Technical Reports Server (NTRS)
Loewenthal, William S.; Ellis, David L.
2008-01-01
This report is a section of the final report on the GRCop-84 task of the Constellation Program and incorporates the results obtained between October 2000 and September 2005, when the program ended. NASA Glenn Research Center (GRC) has developed a new copper alloy, GRCop-84 (Cu-8 at.% Cr-4 at.% Nb), for rocket engine main combustion chamber components that will improve rocket engine life and performance. This work examines the sensitivity of GRCop-84 mechanical properties to rolling parameters as a means to better define rolling parameters for commercial warm rolling. Experiment variables studied were total reduction, rolling temperature, rolling speed, and post rolling annealing heat treatment. The responses were tensile properties measured at 23 and 500 C, hardness, and creep at three stress-temperature combinations. Understanding these relationships will better define boundaries for a robust commercial warm rolling process. The four processing parameters were varied within limits consistent with typical commercial production processes. Testing revealed that the rolling-related variables selected have a minimal influence on tensile, hardness, and creep properties over the range of values tested. Annealing had the expected result of lowering room temperature hardness and strength while increasing room temperature elongations with 600 C (1112 F) having the most effect. These results indicate that the process conditions to warm roll plate and sheet for these variables can range over wide levels without negatively impacting mechanical properties. Incorporating broader process ranges in future rolling campaigns should lower commercial rolling costs through increased productivity.
Tuning of fault tolerant control design parameters.
DeLima, Pedro G; Yen, Gary G
2008-01-01
This paper presents two major contributions in the field of fault tolerant control. First, it gathers points of concern typical to most fault tolerant control applications and translates the chosen performance metrics into a set of six practical design specifications. Second, it proposes initialization and tuning procedures through which a particular fault tolerant control architecture not only can be set to comply with the required specifications, but also can be tuned online to compensate for a total of twelve properties, such as the noise rejection levels for fault detection and diagnosis signals. The proposed design is realized over a powerful architecture that combines the flexibility of adaptive critic designs with the long term memory and learning capabilities of a supervisor. This paper presents a practical design procedure to facilitate the applications of a fundamentally sound fault tolerant control architecture in real-world problems.
NASA Astrophysics Data System (ADS)
Joodaki, S.; Yang, Z.; Niemi, A. P.
2016-12-01
CO2 trapping in saline aquifers can be enhanced by applying specific injection strategies. Water-alternating-gas (WAG) injection, in which intermittent slugs of CO2 and water are injected, is one of the suggested methods to increase the trapping of CO2 as a result of both capillary forces (residual trapping) and dissolution into the ambient water (dissolution trapping). In this study, 3D numerical modeling was used to investigate the importance of parameters needed to design an effective WAG injection sequence including (i) CO2 and water injection rates, (ii) WAG ratio, (iii) number of cycles and their duration. We employ iTOUGH2-EOS17 model to simulate the CO2 injection and subsequent trapping in heterogeneous formations. Spatially correlated random permeability fields are generated using GSLIB based on available data at the Heletz, a pilot injection site in Israel, aimed for scientifically motivated CO2 injection experiments. Hysteresis effects on relative permeability and capillary pressure function are taken into account based on the Land model (1968). The results showed that both residual and dissolution trapping can be enhanced by increasing in CO2 injection rate due to the fact that higher CO2 injection rate reduces the gravity segregation and increases the reservoir volume swept by CO2. Faster water injection will favor the residual and dissolution trapping due to improved mixing. Increasing total amount of water injection will increase the dissolution trapping but also the cost of the injection. It causes higher pressure increases as well. Using numerical modeling, it is possible to predict the best parameter combination to optimize the trapping and find the balance between safety and cost of the injection process.
A study of parameter identification
NASA Technical Reports Server (NTRS)
Herget, C. J.; Patterson, R. E., III
1978-01-01
A set of definitions for deterministic parameter identification ability were proposed. Deterministic parameter identificability properties are presented based on four system characteristics: direct parameter recoverability, properties of the system transfer function, properties of output distinguishability, and uniqueness properties of a quadratic cost functional. Stochastic parameter identifiability was defined in terms of the existence of an estimation sequence for the unknown parameters which is consistent in probability. Stochastic parameter identifiability properties are presented based on the following characteristics: convergence properties of the maximum likelihood estimate, properties of the joint probability density functions of the observations, and properties of the information matrix.
Mühlfeld, Christian; Ochs, Matthias
2013-08-01
Design-based stereology provides efficient methods to obtain valuable quantitative information of the respiratory tract in various diseases. However, the choice of the most relevant parameters in a specific disease setting has to be deduced from the present pathobiological knowledge. Often it is difficult to express the pathological alterations by interpretable parameters in terms of volume, surface area, length, or number. In the second part of this companion review article, we analyze the present pathophysiological knowledge about acute lung injury, diffuse parenchymal lung diseases, emphysema, pulmonary hypertension, and asthma to come up with recommendations for the disease-specific application of stereological principles for obtaining relevant parameters. Worked examples with illustrative images are used to demonstrate the work flow, estimation procedure, and calculation and to facilitate the practical performance of equivalent analyses.
Consideration of Design Parameters of Ultrasonic Transducer for Fruit
NASA Astrophysics Data System (ADS)
Kim, K. B.; Kim, M. S.; Lee, S. D.; Choi, M. Y.
2005-04-01
This study was conducted to develop the ultrasonic transducers for non-destructive contact measurement of fruits. The design parameters for ultrasonic transducer such as acoustical impedance of fruits, kinds of piezoelectric materials, ultrasonic wave frequency, and transducer diameter were investigated. In order to match the impedance between piezoelectric material and fruit, various materials were evaluated. And to control the bandwidth of ultrasonic wave of the transducer, various backing materials were fabricated and evaluated. Especially, the wear plate of the transducer was designed and fabricated considering curvature of fruit. Finally, the ultrasonic transducer having 100 kHz of central frequency were fabricated and tested.
100 km CEPC parameters and lattice design
NASA Astrophysics Data System (ADS)
Wang, D.; Gao, J.; Yu, C. H.; Zhang, Y.; Wang, Y. W.; Su, F.; Y Zhai, J.; Bai, S.; Geng, H. P.; Bian, T. J.; Wang, N.; Cui, X. H.; Zhang, C.; Qin, Q.
2017-07-01
The 100km double ring configuration with shared superconducting RF system has been defined as baseline by the circular electron positron collider (CEPC) steering committee. Based on this new scheme, we will get higher luminosity for Higgs (+170%) keeping the beam power in preliminary conceptual design report (Pre-CDR) or to reduce the beam power (19 MW) while keeping same luminosity. CEPC will be compatible with W and Z experiment. The luminosity for Z is designed at the level of 1035 cm-2s-1. The requirement for the energy acceptance of Higgs has been reduced to 1.5% by enlarging the ring to 100 km. The optics of arc and final focus system (FFS) with crab sextupoles has been designed, and also some primary dynamic aperture (DA) results were introduced. Work supported by the National Key Programme for S&T Research and Development (Grant NO. 2016YFA0400400) and the National Natural Science Foundation of China (11505198, 11575218, 11605210 and 11605211).
Robust parameter design for automatically controlled systems and nanostructure synthesis
NASA Astrophysics Data System (ADS)
Dasgupta, Tirthankar
2007-12-01
This research focuses on developing comprehensive frameworks for developing robust parameter design methodology for dynamic systems with automatic control and for synthesis of nanostructures. In many automatically controlled dynamic processes, the optimal feedback control law depends on the parameter design solution and vice versa and therefore an integrated approach is necessary. A parameter design methodology in the presence of feedback control is developed for processes of long duration under the assumption that experimental noise factors are uncorrelated over time. Systems that follow a pure-gain dynamic model are considered and the best proportional-integral and minimum mean squared error control strategies are developed by using robust parameter design. The proposed method is illustrated using a simulated example and a case study in a urea packing plant. This idea is also extended to cases with on-line noise factors. The possibility of integrating feedforward control with a minimum mean squared error feedback control scheme is explored. To meet the needs of large scale synthesis of nanostructures, it is critical to systematically find experimental conditions under which the desired nanostructures are synthesized reproducibly, at large quantity and with controlled morphology. The first part of the research in this area focuses on modeling and optimization of existing experimental data. Through a rigorous statistical analysis of experimental data, models linking the probabilities of obtaining specific morphologies to the process variables are developed. A new iterative algorithm for fitting a Multinomial GLM is proposed and used. The optimum process conditions, which maximize the above probabilities and make the synthesis process less sensitive to variations of process variables around set values, are derived from the fitted models using Monte-Carlo simulations. The second part of the research deals with development of an experimental design methodology, tailor
Parameter studies for traveling wave coaxial launchers
Wu, A.Y. . Center for Electromechanics)
1991-01-01
The traveling wave coaxial launcher is a complex machine that requires very extensive parameter studies to optimize. Most of previous attempts to realize hypervelocity using coaxial launchers have failed partly due to inadequate analyses. This paper reports the results of very extensive air-core coaxial launcher parameter studies performed using computers. These results and the methodology introduced should help future researchers on this topic. In the course of studying the feasibility of accelerating a 1-kg projectile to 10 km/s with an 18 m air-core multiphase coaxial launcher powered by a rising frequency generator (RFGs), a complete simulation code based on the current filament method was developed. Results from the simulation code indicate rather chaotic behavior of an arbitrary coaxial launcher design. More fundamental studies were then conducted using various computer codes based on the current filament method.
Multiobjective insensitive design of airplane control systems with uncertain parameters
NASA Technical Reports Server (NTRS)
Schy, A. A.; Giesy, D. P.
1981-01-01
A multiobjective computer-aided design algorithm has been developed which minimizes the sensitivity of the design objectives to uncertainties in system parameters. The more important uncertain parameters are described by a gaussian random vector with known covariance matrix, and a vector sensitivity objective function is defined as the probabilities that the design objectives will violate specified requirements constraints. Control system parameters are found which minimize the sensitivity vector in a Pareto-optimal sense, using constrained minimization algorithms. Example results are shown for lateral stability augmentation system (SAS) design for three Shuttle flight conditions.
IR design and parameters of APIARY VI
Donald, M.; Garren, A.; Hutton, A.; Sullivan, M.
1990-05-29
A layout for head on collisions with flat beams is described which meets the requirements of the B Factory in all of the initial checks we have performed. It must now be refined and subjected to more rigorous tests to ensure that this is really an acceptable solution. In particular, engineering studies on septum quads should be initiated.
Tuning Parameters in Heuristics by Using Design of Experiments Methods
NASA Technical Reports Server (NTRS)
Arin, Arif; Rabadi, Ghaith; Unal, Resit
2010-01-01
With the growing complexity of today's large scale problems, it has become more difficult to find optimal solutions by using exact mathematical methods. The need to find near-optimal solutions in an acceptable time frame requires heuristic approaches. In many cases, however, most heuristics have several parameters that need to be "tuned" before they can reach good results. The problem then turns into "finding best parameter setting" for the heuristics to solve the problems efficiently and timely. One-Factor-At-a-Time (OFAT) approach for parameter tuning neglects the interactions between parameters. Design of Experiments (DOE) tools can be instead employed to tune the parameters more effectively. In this paper, we seek the best parameter setting for a Genetic Algorithm (GA) to solve the single machine total weighted tardiness problem in which n jobs must be scheduled on a single machine without preemption, and the objective is to minimize the total weighted tardiness. Benchmark instances for the problem are available in the literature. To fine tune the GA parameters in the most efficient way, we compare multiple DOE models including 2-level (2k ) full factorial design, orthogonal array design, central composite design, D-optimal design and signal-to-noise (SIN) ratios. In each DOE method, a mathematical model is created using regression analysis, and solved to obtain the best parameter setting. After verification runs using the tuned parameter setting, the preliminary results for optimal solutions of multiple instances were found efficiently.
Design Parameters Influencing Reliability of CCGA Assembly: A Sensitivity Analysis
NASA Technical Reports Server (NTRS)
Tasooji, Amaneh; Ghaffarian, Reza; Rinaldi, Antonio
2006-01-01
Area Array microelectronic packages with small pitch and large I/O counts are now widely used in microelectronics packaging. The impact of various package design and materials/process parameters on reliability has been studied through extensive literature review. Reliability of Ceramic Column Grid Array (CCGA) package assemblies has been evaluated using JPL thermal cycle test results (-50(deg)/75(deg)C, -55(deg)/100(deg)C, and -55(deg)/125(deg)C), as well as those reported by other investigators. A sensitivity analysis has been performed using the literature da to study the impact of design parameters and global/local stress conditions on assembly reliability. The applicability of various life-prediction models for CCGA design has been investigated by comparing model's predictions with the experimental thermal cycling data. Finite Element Method (FEM) analysis has been conducted to assess the state of the stress/strain in CCGA assembly under different thermal cycling, and to explain the different failure modes and locations observed in JPL test assemblies.
Design Parameters Influencing Reliability of CCGA Assembly: A Sensitivity Analysis
NASA Technical Reports Server (NTRS)
Tasooji, Amaneh; Ghaffarian, Reza; Rinaldi, Antonio
2006-01-01
Area Array microelectronic packages with small pitch and large I/O counts are now widely used in microelectronics packaging. The impact of various package design and materials/process parameters on reliability has been studied through extensive literature review. Reliability of Ceramic Column Grid Array (CCGA) package assemblies has been evaluated using JPL thermal cycle test results (-50(deg)/75(deg)C, -55(deg)/100(deg)C, and -55(deg)/125(deg)C), as well as those reported by other investigators. A sensitivity analysis has been performed using the literature da to study the impact of design parameters and global/local stress conditions on assembly reliability. The applicability of various life-prediction models for CCGA design has been investigated by comparing model's predictions with the experimental thermal cycling data. Finite Element Method (FEM) analysis has been conducted to assess the state of the stress/strain in CCGA assembly under different thermal cycling, and to explain the different failure modes and locations observed in JPL test assemblies.
Aerodynamic optimization by simultaneously updating flow variables and design parameters
NASA Technical Reports Server (NTRS)
Rizk, M. H.
1990-01-01
The application of conventional optimization schemes to aerodynamic design problems leads to inner-outer iterative procedures that are very costly. An alternative approach is presented based on the idea of updating the flow variable iterative solutions and the design parameter iterative solutions simultaneously. Two schemes based on this idea are applied to problems of correcting wind tunnel wall interference and optimizing advanced propeller designs. The first of these schemes is applicable to a limited class of two-design-parameter problems with an equality constraint. It requires the computation of a single flow solution. The second scheme is suitable for application to general aerodynamic problems. It requires the computation of several flow solutions in parallel. In both schemes, the design parameters are updated as the iterative flow solutions evolve. Computations are performed to test the schemes' efficiency, accuracy, and sensitivity to variations in the computational parameters.
A two-parameter design storm for Mediterranean convective rainfall
NASA Astrophysics Data System (ADS)
García-Bartual, Rafael; Andrés-Doménech, Ignacio
2017-05-01
The following research explores the feasibility of building effective design storms for extreme hydrological regimes, such as the one which characterizes the rainfall regime of the east and south-east of the Iberian Peninsula, without employing intensity-duration-frequency (IDF) curves as a starting point. Nowadays, after decades of functioning hydrological automatic networks, there is an abundance of high-resolution rainfall data with a reasonable statistic representation, which enable the direct research of temporal patterns and inner structures of rainfall events at a given geographic location, with the aim of establishing a statistical synthesis directly based on those observed patterns. The authors propose a temporal design storm defined in analytical terms, through a two-parameter gamma-type function. The two parameters are directly estimated from 73 independent storms identified from rainfall records of high temporal resolution in Valencia (Spain). All the relevant analytical properties derived from that function are developed in order to use this storm in real applications. In particular, in order to assign a probability to the design storm (return period), an auxiliary variable combining maximum intensity and total cumulated rainfall is introduced. As a result, for a given return period, a set of three storms with different duration, depth and peak intensity are defined. The consistency of the results is verified by means of comparison with the classic method of alternating blocks based on an IDF curve, for the above mentioned study case.
NASA Astrophysics Data System (ADS)
Clark, P.; White, R. G.
1993-01-01
When attempting to control the vibration transmitted from machinery installations, perhaps with a view to reducing the unwanted radiation of noise at a point remote from the source, it is essential that all possible transmission paths are considered. With the majority of industrial machinery installations it is one-dimensional or beam-like structures - for example, pipework and other mechanical linkages - which form one of the main vibration paths which bypass isolator systems. It is of interest to consider the effects that the addition of certain discontinuities to this type of structure would have on the overall vibration transmission properties of the complete system. The discontinuity considered in detail in this report is the vibration neutralizer. By utilizing the concept of vibrational power transmission, the effects of varying design parameters on the performance of a neutralizer as a vibration attenuator are considered.
Dennison, Thomas J; Smith, Julian; Hofmann, Michael P; Bland, Charlotte E; Badhan, Raj K; Al-Khattawi, Ali; Mohammed, Afzal R
2016-01-01
Atomisation of an aqueous solution for tablet film coating is a complex process with multiple factors determining droplet formation and properties. The importance of droplet size for an efficient process and a high quality final product has been noted in the literature, with smaller droplets reported to produce smoother, more homogenous coatings whilst simultaneously avoiding the risk of damage through over-wetting of the tablet core. In this work the effect of droplet size on tablet film coat characteristics was investigated using X-ray microcomputed tomography (XμCT) and confocal laser scanning microscopy (CLSM). A quality by design approach utilising design of experiments (DOE) was used to optimise the conditions necessary for production of droplets at a small (20 μm) and large (70 μm) droplet size. Droplet size distribution was measured using real-time laser diffraction and the volume median diameter taken as a response. DOE yielded information on the relationship three critical process parameters: pump rate, atomisation pressure and coating-polymer concentration, had upon droplet size. The model generated was robust, scoring highly for model fit (R2 = 0.977), predictability (Q2 = 0.837), validity and reproducibility. Modelling confirmed that all parameters had either a linear or quadratic effect on droplet size and revealed an interaction between pump rate and atomisation pressure. Fluidised bed coating of tablet cores was performed with either small or large droplets followed by CLSM and XμCT imaging. Addition of commonly used contrast materials to the coating solution improved visualisation of the coating by XμCT, showing the coat as a discrete section of the overall tablet. Imaging provided qualitative and quantitative evidence revealing that smaller droplets formed thinner, more uniform and less porous film coats.
Dennison, Thomas J.; Smith, Julian; Hofmann, Michael P.; Bland, Charlotte E.; Badhan, Raj K.; Al-Khattawi, Ali; Mohammed, Afzal R.
2016-01-01
Atomisation of an aqueous solution for tablet film coating is a complex process with multiple factors determining droplet formation and properties. The importance of droplet size for an efficient process and a high quality final product has been noted in the literature, with smaller droplets reported to produce smoother, more homogenous coatings whilst simultaneously avoiding the risk of damage through over-wetting of the tablet core. In this work the effect of droplet size on tablet film coat characteristics was investigated using X-ray microcomputed tomography (XμCT) and confocal laser scanning microscopy (CLSM). A quality by design approach utilising design of experiments (DOE) was used to optimise the conditions necessary for production of droplets at a small (20 μm) and large (70 μm) droplet size. Droplet size distribution was measured using real-time laser diffraction and the volume median diameter taken as a response. DOE yielded information on the relationship three critical process parameters: pump rate, atomisation pressure and coating-polymer concentration, had upon droplet size. The model generated was robust, scoring highly for model fit (R2 = 0.977), predictability (Q2 = 0.837), validity and reproducibility. Modelling confirmed that all parameters had either a linear or quadratic effect on droplet size and revealed an interaction between pump rate and atomisation pressure. Fluidised bed coating of tablet cores was performed with either small or large droplets followed by CLSM and XμCT imaging. Addition of commonly used contrast materials to the coating solution improved visualisation of the coating by XμCT, showing the coat as a discrete section of the overall tablet. Imaging provided qualitative and quantitative evidence revealing that smaller droplets formed thinner, more uniform and less porous film coats. PMID:27548263
Design and parameter optimization of flip-chip bonder
NASA Astrophysics Data System (ADS)
Shim, Hyoungsub; Kang, Heuiseok; Jeong, Hoon; Cho, Youngjune; Kim, Wansoo; Kang, Shinill
2005-12-01
Bare-chip packaging becomes more popular along with the miniaturization of IT components. In this paper, we have studied flip-chip process, and developed automated bonding system. Among the several bonding method, NCP bonding is chosen and batch-type equipment is manufactured. The dual optics and vision system aligns the chip with the substrate. The bonding head equipped with temperature and force controllers bonds the chip. The system can be easily modified for other bonding methods such as ACF. In bonding process, the bonding force and temperature are known as the most dominant bonding parameters. A parametric study is performed for these two parameters. For the test sample, we used standard flip-chip test kit which consists of FR4 boards and dummy flip-chips. The bonding temperatures are chosen between 25°C to 300°C. The bonding forces are chosen between 5N and 300N. To test the bonding strength, a bonding strength tester was designed and constructed. After the bonding strength test, the samples are examined by microscope to determine the failure mode. The relations between the bonding strength and the bonding parameters are analyzed and compared with bonding models. Finally, the most suitable bonding condition is suggested in terms of temperature and force.
Total energy control system autopilot design with constrained parameter optimization
NASA Technical Reports Server (NTRS)
Ly, Uy-Loi; Voth, Christopher
1990-01-01
A description is given of the application of a multivariable control design method (SANDY) based on constrained parameter optimization to the design of a multiloop aircraft flight control system. Specifically, the design method is applied to the direct synthesis of a multiloop AFCS inner-loop feedback control system based on total energy control system (TECS) principles. The design procedure offers a structured approach for the determination of a set of stabilizing controller design gains that meet design specifications in closed-loop stability, command tracking performance, disturbance rejection, and limits on control activities. The approach can be extended to a broader class of multiloop flight control systems. Direct tradeoffs between many real design goals are rendered systematic by proper formulation of the design objectives and constraints. Satisfactory designs are usually obtained in few iterations. Performance characteristics of the optimized TECS design have been improved, particularly in the areas of closed-loop damping and control activity in the presence of turbulence.
Knitted Strain Sensors: Impact of Design Parameters on Sensing Properties
Atalay, Ozgur; Kennon, William Richard
2014-01-01
This paper presents a study of the sensing properties exhibited by textile-based knitted strain sensors. Knitted sensors were manufactured using flat-bed knitting technology, and electro-mechanical tests were subsequently performed on the specimens using a tensile testing machine to apply strain whilst the sensor was incorporated into a Wheatstone bridge arrangement to allow electrical monitoring. The sensing fabrics were manufactured from silver-plated nylon and elastomeric yarns. The component yarns offered similar diameters, bending characteristics and surface friction, but their production parameters differed in respect of the required yarn input tension, the number of conductive courses in the sensing structure and the elastomeric yarn extension characteristics. Experimental results showed that these manufacturing controls significantly affected the sensing properties of the knitted structures such that the gauge factor values, the working range and the linearity of the sensors varied according to the knitted structure. These results confirm that production parameters play a fundamental role in determining the physical behavior and the sensing properties of knitted sensors. It is thus possible to manipulate the sensing properties of knitted sensors and the sensor response may be engineered by varying the production parameters applied to specific designs. PMID:24608010
The shear instability energy: a new parameter for materials design?
NASA Astrophysics Data System (ADS)
Kanani, M.; Hartmaier, A.; Janisch, R.
2017-10-01
Reliable and predictive relationships between fundamental microstructural material properties and observable macroscopic mechanical behaviour are needed for the successful design of new materials. In this study we establish a link between physical properties that are defined on the atomic level and the deformation mechanisms of slip planes and interfaces that govern the mechanical behaviour of a metallic material. To accomplish this, the shear instability energy Γ is introduced, which can be determined via quantum mechanical ab initio calculations or other atomistic methods. The concept is based on a multilayer generalised stacking fault energy calculation and can be applied to distinguish the different shear deformation mechanisms occurring at TiAl interfaces during finite-temperature molecular dynamics simulations. We use the new parameter Γ to construct a deformation mechanism map for different interfaces occurring in this intermetallic. Furthermore, Γ can be used to convert the results of ab initio density functional theory calculations into those obtained with an embedded atom method type potential for TiAl. We propose to include this new physical parameter into material databases to apply it for the design of materials and microstructures, which so far mainly relies on single-crystal values for the unstable and stable stacking fault energy.
Experimental investigation of design parameters on dry powder inhaler performance.
Ngoc, Nguyen Thi Quynh; Chang, Lusi; Jia, Xinli; Lau, Raymond
2013-11-30
The study aims to investigate the impact of various design parameters of a dry powder inhaler on the turbulence intensities generated and the performance of the dry powder inhaler. The flow fields and turbulence intensities in the dry powder inhaler are measured using particle image velocimetry (PIV) techniques. In vitro aerosolization and deposition a blend of budesonide and lactose are measured using an Andersen Cascade Impactor. Design parameters such as inhaler grid hole diameter, grid voidage and chamber length are considered. The experimental results reveal that the hole diameter on the grid has negligible impact on the turbulence intensity generated in the chamber. On the other hand, hole diameters smaller than a critical size can lead to performance degradation due to excessive particle-grid collisions. An increase in grid voidage can improve the inhaler performance but the effect diminishes at high grid voidage. An increase in the chamber length can enhance the turbulence intensity generated but also increases the powder adhesion on the inhaler wall.
Loss of Information in Estimating Item Parameters in Incomplete Designs
ERIC Educational Resources Information Center
Eggen, Theo J. H. M.; Verelst, Norman D.
2006-01-01
In this paper, the efficiency of conditional maximum likelihood (CML) and marginal maximum likelihood (MML) estimation of the item parameters of the Rasch model in incomplete designs is investigated. The use of the concept of F-information (Eggen, 2000) is generalized to incomplete testing designs. The scaled determinant of the F-information…
Loss of Information in Estimating Item Parameters in Incomplete Designs
ERIC Educational Resources Information Center
Eggen, Theo J. H. M.; Verelst, Norman D.
2006-01-01
In this paper, the efficiency of conditional maximum likelihood (CML) and marginal maximum likelihood (MML) estimation of the item parameters of the Rasch model in incomplete designs is investigated. The use of the concept of F-information (Eggen, 2000) is generalized to incomplete testing designs. The scaled determinant of the F-information…
Design parameters for the damped detuned accelerating structure
Ko, K.; Bane, K.; Gluckstern, R.; Hoag, H.; Kroll, N.; Lin, X.T.; Miller, R.; Ruth, R.; Thompson, K.; Wang, J. ||
1995-06-01
The advanced accelerating cavities for the NLCTA (and anticipated for NLC) will incorporate damping as well as detuning. The damping is provided by a set of four waveguides (which also serve as pumping manifolds) that run parallel to the structure, with strong iris coupling to each cavity cell and terminated at each end by absorbers. The previously reported equivalent circuit analysis has been refined and the dependence upon design parameters explored. The authors find that adequate damping can be provided by a single waveguide mode, leading to designs which are more compact than those initially considered. The design parameters and their rationale will be presented.
Concurrent optimization of airframe and engine design parameters
NASA Technical Reports Server (NTRS)
Lavelle, Thomas M.; Plencner, Robert M.; Seidel, Jonathan A.
1991-01-01
An integrated system for the multidisciplinary analysis and optimization of airframe and propulsion design parameters is being developed. This system is known as IPAS, the Integrated Propulsion/Airframe Analysis System. The traditional method of analysis is one in which the propulsion system analysis is loosely coupled to the overall mission performance analysis. This results in a time consuming iterative process. First, the engine is designed and analyzed. Then, the results from this analysis are used in a mission analysis to determine the overall aircraft performance. The results from the mission analysis are used as a guide as the engine is redesigned and the entire process repeated. In IPAS, the propulsion system, airframe, and mission are closely coupled. The propulsion system analysis code is directly integrated into the mission analysis code. This allows the propulsion design parameters to be optimized along with the airframe and mission design parameters, significantly reducing the time required to obtain an optimized solution.
Abdulra'uf, Lukman Bola; Tan, Guan Huat
2013-12-15
Solid-phase microextraction (SPME) is a solvent-less sample preparation method which combines sample preparation, isolation, concentration and enrichment into one step. In this study, multivariate strategy was used to determine the significance of the factors affecting the solid phase microextraction of pesticide residues (fenobucarb, diazinon, chlorothalonil and chlorpyrifos) using a randomised factorial design. The interactions and effects of temperature, time and salt addition on the efficiency of the extraction of the pesticide residues were evaluated using 2(3) factorial designs. The analytes were extracted with 100 μm PDMS fibres according to the factorial design matrix and desorbed into a gas chromatography-mass spectrometry detector. The developed method was applied for the analysis of apple samples and the limits of detection were between 0.01 and 0.2 μg kg(-)(1), which were lower than the MRLs for apples. The relative standard deviations (RSD) were between 0.1% and 13.37% with average recovery of 80-105%. The linearity ranges from 0.5-50 μg kg(-)(1) with correlation coefficient greater than 0.99. Copyright © 2013 Elsevier Ltd. All rights reserved.
Stereolithographic Bone Scaffold Design Parameters: Osteogenic Differentiation and Signal Expression
Kim, Kyobum; Yeatts, Andrew; Dean, David
2010-01-01
Scaffold design parameters including porosity, pore size, interconnectivity, and mechanical properties have a significant influence on osteogenic signal expression and differentiation. This review evaluates the influence of each of these parameters and then discusses the ability of stereolithography (SLA) to be used to tailor scaffold design to optimize these parameters. Scaffold porosity and pore size affect osteogenic cell signaling and ultimately in vivo bone tissue growth. Alternatively, scaffold interconnectivity has a great influence on in vivo bone growth but little work has been done to determine if interconnectivity causes changes in signaling levels. Osteogenic cell signaling could be also influenced by scaffold mechanical properties such as scaffold rigidity and dynamic relationships between the cells and their extracellular matrix. With knowledge of the effects of these parameters on cellular functions, an optimal tissue engineering scaffold can be designed, but a proper technology must exist to produce this design to specification in a repeatable manner. SLA has been shown to be capable of fabricating scaffolds with controlled architecture and micrometer-level resolution. Surgical implantation of these scaffolds is a promising clinical treatment for successful bone regeneration. By applying knowledge of how scaffold parameters influence osteogenic cell signaling to scaffold manufacturing using SLA, tissue engineers may move closer to creating the optimal tissue engineering scaffold. PMID:20504065
Control design for a class of nonlinear parameter varying systems
NASA Astrophysics Data System (ADS)
Cai, Xiushan; Liu, Yang; Zhang, Wei
2015-07-01
Stabilisation for a class of one-sided Lipschitz nonlinear parameter varying systems is dealt with in this paper. First, the nonlinear parameter varying system is represented as a subsystem of a differential inclusion. Sufficient conditions for exponential stabilisation for the differential inclusion are given by solving linear matrix inequalities. Then a continuous control law is designed to stabilise the differential inclusion. It leads to stabilising the nonlinear parameter varying system. Finally, a simulation example is presented to show the validity and advantages of the proposed method.
Parameters and variables appearing in repository design models
Curtis, R.H.; Wart, R.J.
1983-12-01
This report defines the parameters and variables appearing in repository design models and presents typical values and ranges of values of each. Areas covered by this report include thermal, geomechanical, and coupled stress and flow analyses in rock. Particular emphasis is given to conductivity, radiation, and convection parameters for thermal analysis and elastic constants, failure criteria, creep laws, and joint properties for geomechanical analysis. The data in this report were compiled to help guide the selection of values of parameters and variables to be used in code benchmarking. 102 references, 33 figures, 51 tables.
Use of field parameters in wind engineering design
Stathopoulos, T. )
1989-05-01
The paper presents a useful compendium of information related to the uncertainty of parameters used in wind engineering design. This information is required for reliability-based wind standards and codes of practice as well as structural design. It is suggested in the paper that for the estimation of the integral scale of turbulence, the correlation integral approach provides data with higher uncertainty in comparison with that obtained through spectral estimation. There are two types of modeling uncertainties described.
Parameter Studies for the VISTA Spacecraft Concept
Orth, C D
2000-11-21
The baseline design for the VISTA spacecraft concept employs a diode-pumped solid-state laser (DPSSL) driver. This type of driver is now under development at LLNL and elsewhere as an extension of the mature solid-state (glass) laser technology developed for terrestrial applications of inertial confinement fusion (ICF). A DPSSL is repratable up to at least 30 Hz, and has an efficiency soon to be experimentally verified of at least 10%. By using a detailed systems code including the essential physics of a DPSSL, we have run parameter studies for the baseline roundtrip (RT) to Mars with a 100-ton payload. We describe the results of these studies as a function of the optimized (minimum) RT flight duration. We also demonstrate why DT fuel gives the best performance, although DD, D3He, or even antimatter can be used, and why DT-ignited DD is probably the fuel most preferred. We also describe the overall power flow, showing where the fusion energy is ultimately utilized, and estimate the variation in performance to the planets dictated by variations in target gain and other parameters.
Distillation tray structural parameter study: Phase 1
NASA Technical Reports Server (NTRS)
Winter, J. Ronald
1991-01-01
The purpose here is to identify the structural parameters (plate thickness, liquid level, beam size, number of beams, tray diameter, etc.) that affect the structural integrity of distillation trays in distillation columns. Once the sensitivity of the trays' dynamic response to these parameters has been established, the designer will be able to use this information to prepare more accurate specifications for the construction of new trays. Information is given on both static and dynamic analysis, modal response, and tray failure details.
Design of Fiber Optic Sensors for Measuring Hydrodynamic Parameters
NASA Technical Reports Server (NTRS)
Lyons, Donald R.; Quiett, Carramah; Griffin, DeVon (Technical Monitor)
2001-01-01
The science of optical hydrodynamics involves relating the optical properties to the fluid dynamic properties of a hydrodynamic system. Fiber-optic sensors are being designed for measuring the hydrodynamic parameters of various systems. As a flowing fluid makes an encounter with a flat surface, it forms a boundary layer near this surface. The region between the boundary layer and the flat plate contains information about parameters such as viscosity, compressibility, pressure, density, and velocity. An analytical model has been developed for examining the hydrodynamic parameters near the surface of a fiber-optic sensor. An analysis of the conservation of momentum, the continuity equation and the Navier-Stokes equation for compressible flow were used to develop expressions for the velocity and the density as a function of the distance along the flow and above the surface. When examining the flow near the surface, these expressions are used to estimate the sensitivity required to perform direct optical measurements and to derive the shear force for indirect optical measurements. The derivation of this result permits the incorporation of better design parameters for other fiber-based sensors. Future work includes analyzing the optical parametric designs of fiber-optic sensors, modeling sensors to utilize the parameters for hydrodynamics and applying different mixtures of hydrodynamic flow. Finally, the fabrication of fiber-optic sensors for hydrodynamic flow applications of the type described in this presentation could enhance aerospace, submarine, and medical technology.
Parameter Scaling and Practical Design of TME Lattice
Jiao, Yi; Cai, Yunhai; Chao, Alex; /SLAC /Beijing, Inst. High Energy Phys. /SLAC
2011-11-08
It is a challenge to produce a practical design of an electron storage ring with a theorectical minimum emittance (TME) lattice of ultra low emittance, e.g. several pico-meters, due to the very strong focusing and extremely large natural chromaticity associated to these lattice designs. To help dealing with this challenge, it is requisite to scale the parameters and look for a best solution. In this paper, the parameter scaling is summarized, and it is argued that, with the lattice configuration with defocusing quadrupole closer to the dipole or just defocusing dipole, one can reach a good balance of the low emittance and relative small natural chromaticity, with phase advance per half cell below {pi}/2. The 10 pm TME lattice for PEP-X is shown at last as demonstration of the design procedure.
Robust integrated autopilot/autothrottle design using constrained parameter optimization
NASA Technical Reports Server (NTRS)
Ly, Uy-Loi; Voth, Christopher; Sanjay, Swamy
1990-01-01
A multivariable control design method based on constrained parameter optimization was applied to the design of a multiloop aircraft flight control system. Specifically, the design method is applied to the following: (1) direct synthesis of a multivariable 'inner-loop' feedback control system based on total energy control principles; (2) synthesis of speed/altitude-hold designs as 'outer-loop' feedback/feedforward control systems around the above inner loop; and (3) direct synthesis of a combined 'inner-loop' and 'outer-loop' multivariable control system. The design procedure offers a direct and structured approach for the determination of a set of controller gains that meet design specifications in closed-loop stability, command tracking performance, disturbance rejection, and limits on control activities. The presented approach may be applied to a broader class of multiloop flight control systems. Direct tradeoffs between many real design goals are rendered systematic by this method following careful problem formulation of the design objectives and constraints. Performance characteristics of the optimization design were improved over the current autopilot design on the B737-100 Transport Research Vehicle (TSRV) at the landing approach and cruise flight conditions; particularly in the areas of closed-loop damping, command responses, and control activity in the presence of turbulence.
Fan, X; He, L; Lu, H W; Li, J
2014-09-01
This study proposes an environmental- and health-risk-induced remediation design approach for benzene-contaminated groundwater. It involves exposure frequency and intake rates that are important but difficult to be exactly quantified as breakthrough point. Flexible health-risk control is considered in the simulation and optimization work. The proposed approach is then applied to a petroleum-contaminated site in western Canada. Different situations about remediation durations, public concerns, and satisfactory degrees are addressed by the approach. The relationship between environmental standards and health-risk limits is analyzed, in association with their effect on remediation costs. Insights of three uncertain factors (i.e. exposure frequency, intake rate and health-risk threshold) for the remediation system are also explored, on a basis of understanding their impacts on health risk as well as their importance order. The case study results show that (1) nature attenuation plays a more important role in long-term remediation scheme than the pump-and-treat system; (2) carcinogenic risks have greater impact on total pumping rates than environmental standards for long-term remediation; (3) intake rates are the second important factor affecting the remediation system's performance, followed by exposure frequency; (4) the 10-year remediation scheme is the most robust choice when environmental and health-risk concerns are not well quantified. Copyright © 2014 Elsevier Ltd. All rights reserved.
Parameter design considerations for an oscillator IR-FEL
NASA Astrophysics Data System (ADS)
Jia, Qi-Ka
2017-01-01
An infrared oscillator FEL user facility will be built at the National Synchrotron Radiation Laboratory at in Hefei, China. In this paper, the parameter design of the oscillator FEL is discussed, and some original relevant approaches and expressions are presented. Analytic formulae are used to estimate the optical field gain and saturation power for the preliminary design. By considering both physical and technical constraints, the relation of the deflection parameter K to the undulator period is analyzed. This helps us to determine the ranges of the magnetic pole gap, the electron energy and the radiation wavelength. The relations and design of the optical resonator parameters are analyzed. Using dimensionless quantities, the interdependences between the radii of curvature of the resonator mirror and the various parameters of the optical resonator are clearly demonstrated. The effect of the parallel-plate waveguide is analyzed for the far-infrared oscillator FEL. The condition of the necessity of using a waveguide and the modified filling factor in the case of the waveguide are given, respectively. Supported by National Nature Science Foundation of China (21327901, 11375199)
Considerations for design parameters for a dedicated medical accelerator
Alonso, J.R.
1980-10-01
There are only a very few critical parameters which determine the size, performance and cost of a heavy ion accelerator. These are the mass of the heaviest ion desired, the maximum range of this heaviest ion in tissue, and the highest intensity desired. Other parameters, such as beam emittance, beam delivery flexibility, reliability and experimental facility configurations are important, but are not primary driving factors in the design effort. The various clinical applications for a heavy ion accelerator are evaluated, detailing the most desirable beams for each application.
Design Parameters of a Miniaturized Piezoelectric Underwater Acoustic Transmitter
Li, Huidong; Deng, Zhiqun; Yuan, Yong; Carlson, Thomas J.
2012-07-02
The Juvenile Salmon Acoustic Telemetry System (JSATS) project supported by the U.S. Army Corps of Engineers, Portland District, has yielded the smallest acoustic fish tag transmitter commercially available to date. In order to study even smaller fish populations and make the transmitter injectable by needles, the JSATS acoustic micro transmitter needs to be further downsized. As part of the transmitter downsizing effort some of the design parameters of the lead zirconate titanate (PZT) ceramic tube transducer in the transmitter were studied, including the type of PZT, the backing material, the necessary drive voltage, the transmitting bandwidth and the length of the transducer. It was found that, to satisfy the 156-dB source level requirement of JSATS, a square wave with a 10-volt amplitude is required to drive 'soft' PZT transducers. PZT-5H demonstrated the best source level performance. For Navy types I and II, 16 volts or 18 volts were needed. Ethylene-propylene-diene monomer (EPDM) closed-cell foam was found to be the backing material providing the highest source level. The effect of tube length on the source level is also demonstrated in this paper, providing quantitative information for downsizing of small piezoelectric transmitters.
Andrews, Jeff; Likis, Frances E
2015-10-01
To aid authors in correctly naming their study design, to assist readers and reviewers who must decide what the design was for some published studies, and to provide consistency in evaluating the design of published studies, especially for those conducting systematic reviews and evidence synthesis. An annotated algorithm method is used to prompt serial questions and analysis to identify a single study design. The algorithm begins with a research article. Primary clinical research is divided into experimental and observational studies. Key determinants include identifying the study question and the population, intervention, comparison, and outcome. Experimental therapy and prognosis studies are subdivided into 4 design types. Observational therapy and prognosis studies are subdivided into 7 design types. Experimental diagnosis and screening studies are subdivided into 2 types. Observational diagnosis and screening studies are subdivided into 5 types. An annotated algorithm may be used by authors, readers, and reviewers to consistently determine the design of clinical research studies.
Deszczynski, Marcin; Harding, Stephen E; Winzor, Donald J
2006-03-20
The effects of ammonium sulphate concentration on the osmotic second virial coefficient (BAA/MA) for equine serum albumin (pH 5.6, 20 degrees C) have been examined by sedimentation equilibrium. After an initial steep decrease with increasing ammonium sulphate concentration, BAA/MA assumes an essentially concentration-independent magnitude of 8-9 ml/g. Such behaviour conforms with the statistical-mechanical prediction that a sufficient increase in ionic strength should effectively eliminate the contributions of charge interactions to BAA/MA but have no effect on the covolume contribution (8.4 ml/g for serum albumin). A similar situation is shown to apply to published sedimentation equilibrium data for lysozyme (pH 4.5). Although termed osmotic second virial coefficients and designated as such (B22), the negative values obtained in published light scattering studies of both systems have been described incorrectly because of the concomitant inclusion of the protein-salt contribution to thermodynamic nonideality of the protein. Those negative values are still valid predictors of conditions conducive to crystal growth inasmuch as they do reflect situations in which there is net attraction between protein molecules. However, the source of attraction responsible for the negative virial coefficient stems from the protein-salt rather than the protein-protein contribution, which is necessarily positive.
Niederer, Iris; Kriemler, Susi; Zahner, Lukas; Bürgi, Flavia; Ebenegger, Vincent; Hartmann, Tim; Meyer, Ursina; Schindler, Christian; Nydegger, Andreas; Marques-Vidal, Pedro; Puder, Jardena J
2009-03-31
Childhood obesity and physical inactivity are increasing dramatically worldwide. Children of low socioeconomic status and/or children of migrant background are especially at risk. In general, the overall effectiveness of school-based programs on health-related outcomes has been disappointing. A special gap exists for younger children and in high risk groups. This paper describes the rationale, design, curriculum, and evaluation of a multicenter preschool randomized intervention study conducted in areas with a high migrant population in two out of 26 Swiss cantons. Twenty preschool classes in the German (canton St. Gallen) and another 20 in the French (canton Vaud) part of Switzerland were separately selected and randomized to an intervention and a control arm by the use of opaque envelopes. The multidisciplinary lifestyle intervention aimed to increase physical activity and sleep duration, to reinforce healthy nutrition and eating behaviour, and to reduce media use. According to the ecological model, it included children, their parents and the teachers. The regular teachers performed the majority of the intervention and were supported by a local health promoter. The intervention included physical activity lessons, adaptation of the built infrastructure; promotion of regional extracurricular physical activity; playful lessons about nutrition, media use and sleep, funny homework cards and information materials for teachers and parents. It lasted one school year. Baseline and post-intervention evaluations were performed in both arms. Primary outcome measures included BMI and aerobic fitness (20 m shuttle run test). Secondary outcomes included total (skinfolds, bioelectrical impedance) and central (waist circumference) body fat, motor abilities (obstacle course, static and dynamic balance), physical activity and sleep duration (accelerometry and questionnaires), nutritional behaviour and food intake, media use, quality of life and signs of hyperactivity (questionnaires
Qualitative Parameters of Practice during University Studies
ERIC Educational Resources Information Center
Stasiunaitiene, Egle; Norkute, Odeta
2011-01-01
In this article, relevance of practice during university studies is highlighted, as well as the main stages of its organisation, qualitative parameters, as well as criteria and indicators that validate them are defined. Discussion on the idea that taking into consideration qualitative parameters of organising practice as a component of studies…
NASA Astrophysics Data System (ADS)
Yong, Kilyuk; Jo, Sujang; Bang, Hyochoong
This paper presents a modified Rodrigues parameter (MRP)-based nonlinear observer design to estimate bias, scale factor and misalignment of gyroscope measurements. A Lyapunov stability analysis is carried out for the nonlinear observer. Simulation is performed and results are presented illustrating the performance of the proposed nonlinear observer under the condition of persistent excitation maneuver. In addition, a comparison between the nonlinear observer and alignment Kalman filter (AKF) is made to highlight favorable features of the nonlinear observer.
NASA Technical Reports Server (NTRS)
1981-01-01
The results of a preliminary study on the design of a radiation hardened fusible link programmable read-only memory (PROM) are presented. Various fuse technologies and the effects of radiation on MOS integrated circuits are surveyed. A set of design rules allowing the fabrication of a radiation hardened PROM using a Si-gate CMOS process is defined. A preliminary cell layout was completed and the programming concept defined. A block diagram is used to describe the circuit components required for a 4 K design. A design goal data sheet giving target values for the AC, DC, and radiation parameters of the circuit is presented.
Optimizing Hyperspectral Imagery Anomaly Detection through Robust Parameter Design
2011-10-01
THROUGH ROBUST PARAMETER DESIGN DISSERTATION Presented to the Faculty Graduate School of Engineering and Management Air Force Institute of Technology...Air University Air Education and Training Command in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Francis M. Mindrup...Graduate School of Engineering and Management For my loving wife, daughter and sons iv AFIT/DS/ENS/11-04 Abstract Advances in sensor technology
NASA Technical Reports Server (NTRS)
Young, G.
1982-01-01
A design methodology capable of dealing with nonlinear systems, such as a controlled ecological life support system (CELSS), containing parameter uncertainty is discussed. The methodology was applied to the design of discrete time nonlinear controllers. The nonlinear controllers can be used to control either linear or nonlinear systems. Several controller strategies are presented to illustrate the design procedure.
Irradiation Experiment Conceptual Design Parameters for NBSR Fuel Conversion
Brown N. R.; Brown,N.R.; Baek,J.S; Hanson, A.L.; Cuadra,A.; Cheng,L.Y.; Diamond, D.J.
2013-03-31
It has been proposed to convert the National Institute of Standards and Technology (NIST) research reactor, known as the NBSR, from high-enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel. The motivation to convert the NBSR to LEU fuel is to reduce the risk of proliferation of special nuclear material. This report is a compilation of relevant information from recent studies related to the proposed conversion using a metal alloy of LEU with 10 w/o molybdenum. The objective is to inform the design of the mini-plate and full-size plate irradiation experiments that are being planned. This report provides relevant dimensions of the fuel elements, and the following parameters at steady state: average and maximum fission rate density and fission density, fuel temperature distribution for the plate with maximum local temperature, and two-dimensional heat flux profiles of fuel plates with high power densities. . The latter profiles are given for plates in both the inner and outer core zones and for cores with both fresh and depleted shim arms (reactivity control devices). In addition, a summary of the methodology to obtain these results is presented.
Irradiation Experiment Conceptual Design Parameters for NBSR Fuel Conversion
Brown, N. R.; Brown, N. R.; Baek, J. S; Hanson, A. L.; Cuadra, A.; Cheng, L. Y.; Diamond, D. J.
2014-04-30
It has been proposed to convert the National Institute of Standards and Technology (NIST) research reactor, known as the NBSR, from high-enriched uranium (HEU) fuel to low-Enriched uranium (LEU) fuel. The motivation to convert the NBSR to LEU fuel is to reduce the risk of proliferation of special nuclear material. This report is a compilation of relevant information from recent studies related to the proposed conversion using a metal alloy of LEU with 10 w/o molybdenum. The objective is to inform the design of the mini-plate and full-size-Plate irradiation experiments that are being planned. This report provides relevant dimensions of the fuel elements, and the following parameters at steady state: average and maximum fission rate density and fission density, fuel temperature distribution for the plate with maximum local temperature, and two-dimensional heat flux profiles of fuel plates with high power densities. The latter profiles are given for plates in both the inner and outer core zones and for cores with both fresh and depleted shim arms (reactivity control devices). A summary of the methodology to obtain these results is presented. Fuel element tolerance assumptions and hot channel factors used in the safety analysis are also given.
Frequency response and design parameters for differential microbarometers.
Mentink, Johan H; Evers, Läslo G
2011-07-01
The study of infrasound is experiencing a renaissance since it was chosen as a verification technique for the Comprehensive Nuclear-Test-Ban Treaty. Source identification is one of the main topics of research which involves detailed knowledge on the source time function, the atmosphere as medium of propagation, and the measurement system. Applications are also foreseen in using infrasound as passive probe for the upper atmosphere, taking the field beyond its monitoring application. Infrasound can be conveniently measured with differential microbarometers. An accurate description of the instrument response is an essential need to be able to attribute the recorded infrasound to a certain source or atmospheric properties. In this article, a detailed treatment is given of the response of a differential microbarometer to acoustic signals. After an historical introduction, a basic model for the frequency response is derived with its corresponding poles and zeros. The results are explained using electric analogs. In addition, thermal conduction is added to the model in order to capture the transition between adiabatic and isothermal behavior. Also discussed are high-frequency effects and the effect of external temperature variations. Eventually, the design parameters for differential microbarometers are derived. © 2011 Acoustical Society of America
Launch Vehicle Propulsion Parameter Design Multiple Selection Criteria
NASA Technical Reports Server (NTRS)
Shelton, Joey Dewayne
2004-01-01
The optimization tool described herein addresses and emphasizes the use of computer tools to model a system and focuses on a concept development approach for a liquid hydrogen/liquid oxygen single-stage-to-orbit system, but more particularly the development of the optimized system using new techniques. This methodology uses new and innovative tools to run Monte Carlo simulations, genetic algorithm solvers, and statistical models in order to optimize a design concept. The concept launch vehicle and propulsion system were modeled and optimized to determine the best design for weight and cost by varying design and technology parameters. Uncertainty levels were applied using Monte Carlo Simulations and the model output was compared to the National Aeronautics and Space Administration Space Shuttle Main Engine. Several key conclusions are summarized here for the model results. First, the Gross Liftoff Weight and Dry Weight were 67% higher for the design case for minimization of Design, Development, Test and Evaluation cost when compared to the weights determined by the minimization of Gross Liftoff Weight case. In turn, the Design, Development, Test and Evaluation cost was 53% higher for optimized Gross Liftoff Weight case when compared to the cost determined by case for minimization of Design, Development, Test and Evaluation cost. Therefore, a 53% increase in Design, Development, Test and Evaluation cost results in a 67% reduction in Gross Liftoff Weight. Secondly, the tool outputs define the sensitivity of propulsion parameters, technology and cost factors and how these parameters differ when cost and weight are optimized separately. A key finding was that for a Space Shuttle Main Engine thrust level the oxidizer/fuel ratio of 6.6 resulted in the lowest Gross Liftoff Weight rather than at 5.2 for the maximum specific impulse, demonstrating the relationships between specific impulse, engine weight, tank volume and tank weight. Lastly, the optimum chamber pressure for
Test verification and design of the bicycle frame parameters
NASA Astrophysics Data System (ADS)
Zhang, Long; Xiang, Zhongxia; Luo, Huan; Tian, Guan
2015-07-01
Research on design of bicycles is concentrated on mechanism and auto appearance design, however few on matches between the bike and the rider. Since unreasonable human-bike relationship leads to both riders' worn-out joints and muscle injuries, the design of bicycles should focus on the matching. In order to find the best position of human-bike system, simulation experiments on riding comfort under different riding postures are done with the lifemode software employed to facilitate the cycling process as well as to obtain the best position and the size function of it. With BP neural network and GA, analyzing simulation data, conducting regression analysis of parameters on different heights and bike frames, the equation of best position of human-bike system is gained at last. In addition, after selecting testers, customized bikes based on testers' height dimensions are produced according to the size function. By analyzing and comparing the experimental data that are collected from testers when riding common bicycles and customized bicycles, it is concluded that customized bicycles are four times even six times as comfortable as common ones. The equation of best position of human-bike system is applied to improve bikes' function, and the new direction on future design of bicycle frame parameters is presented.
Linear parameter varying representations for nonlinear control design
NASA Astrophysics Data System (ADS)
Carter, Lance Huntington
Linear parameter varying (LPV) systems are investigated as a framework for gain-scheduled control design and optimal hybrid control. An LPV system is defined as a linear system whose dynamics depend upon an a priori unknown but measurable exogenous parameter. A gain-scheduled autopilot design is presented for a bank-to-turn (BTT) missile. The method is novel in that the gain-scheduled design does not involve linearizations about operating points. Instead, the missile dynamics are brought to LPV form via a state transformation. This idea is applied to the design of a coupled longitudinal/lateral BTT missile autopilot. The pitch and yaw/roll dynamics are separately transformed to LPV form, where the cross axis states are treated as "exogenous" parameters. These are actually endogenous variables, so such a plant is called "quasi-LPV." Once in quasi-LPV form, a family of robust controllers using mu synthesis is designed for both the pitch and yaw/roll channels, using angle-of-attack and roll rate as the scheduling variables. The closed-loop time response is simulated using the original nonlinear model and also using perturbed aerodynamic coefficients. Modeling and control of engine idle speed is investigated using LPV methods. It is shown how generalized discrete nonlinear systems may be transformed into quasi-LPV form. A discrete nonlinear engine model is developed and expressed in quasi-LPV form with engine speed as the scheduling variable. An example control design is presented using linear quadratic methods. Simulations are shown comparing the LPV based controller performance to that using PID control. LPV representations are also shown to provide a setting for hybrid systems. A hybrid system is characterized by control inputs consisting of both analog signals and discrete actions. A solution is derived for the optimal control of hybrid systems with generalized cost functions. This is shown to be computationally intensive, so a suboptimal strategy is proposed that
Design parameters for a FM/FM system
NASA Astrophysics Data System (ADS)
Carden, Frank
Design parameters for a FM/FM telemetry system are determined in terms of the IRIG specifications for proportional bandwidth channels. Three mathematical models used by designers of the above processes are extended and compared. That is, FM multi-tone models are used to establish the relationship between frequency deviations, modulation indices, signal-to-noise and IF bandwidth for the IRIG channels. Since spectral efficiency and signal quality are of major importance, a goal of the design is to have a minimum IF bandwidth, while fixing as large as possible the values of the modulation indices for the subcarriers modulating the carrier in order to achieve as large as needed output signal-to-noise ratio.
Design of Life Extending Controls Using Nonlinear Parameter Optimization
NASA Technical Reports Server (NTRS)
Lorenzo, Carl F.; Holmes, Michael S.; Ray, Asok
1998-01-01
This report presents the conceptual development of a life extending control system where the objective is to achieve high performance and structural durability of the plant. A life extending controller is designed for a reusable rocket engine via damage mitigation in both the fuel and oxidizer turbines while achieving high performance for transient responses of the combustion chamber pressure and the O2/H2 mixture ratio. This design approach makes use of a combination of linear and nonlinear controller synthesis techniques and also allows adaptation of the life extending controller module to augment a conventional performance controller of a rocket engine. The nonlinear aspect of the design is achieved using nonlinear parameter optimization of a prescribed control structure.
NASA Technical Reports Server (NTRS)
Rizk, Magdi H.
1988-01-01
A scheme is developed for solving constrained optimization problems in which the objective function and the constraint function are dependent on the solution of the nonlinear flow equations. The scheme updates the design parameter iterative solutions and the flow variable iterative solutions simultaneously. It is applied to an advanced propeller design problem with the Euler equations used as the flow governing equations. The scheme's accuracy, efficiency and sensitivity to the computational parameters are tested.
NASA Technical Reports Server (NTRS)
Rizk, Magdi H.
1988-01-01
A scheme is developed for solving constrained optimization problems in which the objective function and the constraint function are dependent on the solution of the nonlinear flow equations. The scheme updates the design parameter iterative solutions and the flow variable iterative solutions simultaneously. It is applied to an advanced propeller design problem with the Euler equations used as the flow governing equations. The scheme's accuracy, efficiency and sensitivity to the computational parameters are tested.
Lens design based on lens form parameters using Gaussian brackets
NASA Astrophysics Data System (ADS)
Yuan, Xiangyu; Cheng, Xuemin
2014-11-01
The optical power distribution and the symmetry of the lens components are two important attributes that decide the ultimate lens performance and characteristics. Lens form parameters W and S are the key criteria describing the two attributes mentioned above. Lens components with smaller W and S will have a good nature of aberration balance and perform well in providing good image quality. Applying the Gaussian brackets, the two lens form parameters and the Seidel Aberration Coefficients are reconstructed. An initial lens structure can be analytically described by simultaneous equations of Seidel Aberration Coefficients and third-order aberration theory. Adding the constraints of parameters W and S in the solving process, a solution with a proper image quality and aberration distribution is achieved. The optical properties and image quality of the system based on the parameters W and S are also analyzed in this article. In the method, the aberration distribution can be controlled to some extent in the beginning of design, so that we can reduce some workload of optimization later.
[Ergonomic technology. Design study].
Apostol, I; Ciobanu, O
2007-01-01
The paper deals with domains and technological developments and related supports that enhance the rehabilitation process. Ergonomic Technology, Rehabilitation Engineering, Accessibility and Assistive technology are factors involved in promoting a greater independence for people with disabilities by designing and developing new devices with improved design and functionality. Results of a device design study for people with disabilities are presented.
Design Model Parameter Analysis for Nitrifying Trickling Filters.
Coats, Erik R
Nitrifying trickling filters (NTFs) represent an effective technology for water resource recovery facilities (WRRFs) to achieve compliance with ammonia-N permits. However, while the potential benefits of NTFs are many, the design methods and associated parameter databases are underdeveloped. Research herein focused on analysis of pilot-scale NTF data to develop enhanced design guidance. rn(max,0) values ranged from 1.19-3.38 gN m(-2)*d(-1), and correlated with influent ammonia-N concentration and loading. The transition concentration from rn(max,0) ranged from 0.9-22.2 mgN/L, and correlated with ammonia-N loading. Zero-order nitrification ranging from 0.24-1.58 gN m(-2)*d(-1) was observed down-gradient of rn(max,0). First-order nitrification was not observed, nor was there a strong exponential correlation for decreasing nitrification rate. To translate results to NTF media different from that utilized, a relationship between the NTF media effectiveness parameter, E, and rn(max,0) was established. Collectively, the data presented enhances the engineer's ability to model and design NTFs.
Optimizing the Yb:YAG thin disc laser design parameters
NASA Astrophysics Data System (ADS)
Javadi-Dashcasan, M.; Hajiesmaeilbaigi, F.; Razzaghi, H.; Mahdizadeh, M.; Moghadam, M.
2008-09-01
Based on quasi-three-level system, a numerical model of continuous wave thin disc laser is proposed. The fluorescence concentration quenching (FCQ), refractive index depending concentration effects and temperature distribution in the gain medium have been taken into account in the model. The first and second phenomena are not included in previously models. The model is used to determine optimum design parameters and to calculate the influence of various parameters like temperature, number of pump beam passes, active ions concentration and the crystal thickness on the operational efficiency of the laser. This model shows that for higher doping concentrations (>15%) the optical efficiency is decreased due to fluorescence concentration quenching. Our results are excellently in agreement with experimental results.
Parameter-tolerant design of high contrast gratings
NASA Astrophysics Data System (ADS)
Chevallier, Christyves; Fressengeas, Nicolas; Jacquet, Joel; Almuneau, Guilhem; Laaroussi, Youness; Gauthier-Lafaye, Olivier; Cerutti, Laurent; Genty, Frédéric
2015-02-01
This work is devoted to the design of high contrast grating mirrors taking into account the technological constraints and tolerance of fabrication. First, a global optimization algorithm has been combined to a numerical analysis of grating structures (RCWA) to automatically design HCG mirrors. Then, the tolerances of the grating dimensions have been precisely studied to develop a robust optimization algorithm with which high contrast gratings, exhibiting not only a high efficiency but also large tolerance values, could be designed. Finally, several structures integrating previously designed HCGs has been simulated to validate and illustrate the interest of such gratings.
Rhee, B. W.; Ha, K. S.; Park, R. J.; Song, J. H.
2012-07-01
In this paper, a study on the effect of various design parameters such as the channel gap width, heat flux distribution, down-comer pipe size and two-phase flow slip ratio on the natural circulation flow rate is performed based on a physical model for a natural circulation flow along the flow path of the ex-vessel core catcher cooling system of an EU-APR1400, and these effects on the natural circulation flow rate are analyzed and compared with the minimum flow rate required for the safe operation of the system. (authors)
Multivariate Assessment of the Effect of Pump Design and Pump Gap Design Parameters on Blood Trauma.
Graefe, Roland; Henseler, Andreas; Steinseifer, Ulrich
2016-06-01
Pump gaps are the most critical regions in a rotary blood pump when it comes to blood trauma in the form of hemolysis, protein destruction, and platelet activation. This study investigated six pump design parameters affecting the flow in a radial pump gap. A multivariate approach was employed to determine individual and quantitative parameter effects on blood trauma as well as parameter interactions. To consider the effect of shear stress and blood cell residence time, a validated numerical Lagrangian particle tracking approach was used. Based on the results, small-diameter pumps can be as blood compatible, if not more blood compatible, as large-diameter pumps as long as identical circumferential velocities and clearance gaps are maintained. Furthermore, the results indicate that an eccentric rotor position in the casing is not harmful and that a pressure difference generating washout flow and thereby reducing the cell residence time is of significant importance. Copyright © 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.
Design Parameters of a Miniaturized Piezoelectric Underwater Acoustic Transmitter
Li, Huidong; Deng, Zhiqun Daniel; Yuan, Yong; Carlson, Thomas J.
2012-01-01
PZT ceramics have been widely used in underwater acoustic transducers. However, literature available discussing the design parameters of a miniaturized PZT-based low-duty-cycle transmitter is very limited. This paper discusses some of the design parameters—the backing material, driving voltage, PZT material type, power consumption and the transducer length of a miniaturized acoustic fish tag using a PZT tube. Four different types of PZT were evaluated with respect to the source level, energy consumption and bandwidth of the transducer. The effect of the tube length on the source level is discussed. The results demonstrate that ultralow-density closed-cell foam is the best backing material for the PZT tube. The Navy Type VI PZTs provide the best source level with relatively low energy consumption and that a low transducer capacitance is preferred for high efficiency. A 35% reduction in the transducer length results in 2 dB decrease in source level. PMID:23012534
Algorithms of D-optimal designs for Morgan Mercer Flodin (MMF) models with three parameters
NASA Astrophysics Data System (ADS)
Widiharih, Tatik; Haryatmi, Sri; Gunardi, Wilandari, Yuciana
2016-02-01
Morgan Mercer Flodin (MMF) model is used in many areas including biological growth studies, animal and husbandry, chemistry, finance, pharmacokinetics and pharmacodynamics. Locally D-optimal designs for Morgan Mercer Flodin (MMF) models with three parameters are investigated. We used the Generalized Equivalence Theorem of Kiefer and Wolvowitz to determine D-optimality criteria. Number of roots for standardized variance are determined using Tchebysheff system concept and it is used to decide that the design is minimally supported design. In these models, designs are minimally supported designs with uniform weight on its support, and the upper bound of the design region is a support point.
Optimization of reserve lithium thionyl chloride battery electrochemical design parameters
NASA Astrophysics Data System (ADS)
Doddapaneni, N.; Godshall, N. A.
The performance of Reserve Lithium Thionyl Chloride (RLTC) batteries was optimized by conducting a parametric study of seven electrochemical parameters: electrode compression, carbon thickness, presence of catalyst, temperature, electrode limitation, discharge rate, and electrolyte acidity. Increasing electrode compression (from 0 to 15 percent) improved battery performance significantly (10 percent greater carbon capacity density). Although thinner carbon cathodes yielded less absolute capacity than did thicker cathodes, they did so with considerably higher volume efficiencies. The effect of these parameters, and their synergistic interactions, on electrochemical cell performance is illustrated.
Design parameters and source terms: Volume 2, Source terms: Revision 0
Not Available
1987-10-01
The Design Parameters and Source Terms Document was prepared in accordance with DOE request and to provide data for the environmental impact study to be performed in the future for the Deaf Smith County, Texas site for a nuclear waste repository in salt. This document updates a previous unpublished report by Stearns Catalytic Corporation (SCC), entitled ''Design Parameters and Source Terms for a Two-Phase Repository Salt,'' 1985, to the level of the Site Characterization Plan - Conceptual Design Report. The previous unpublished SCC Study identifies the data needs for the Environmental Assessment effort for seven possible Salt Repository sites. 2 tabs.
Effects of Microneedle Design Parameters on Hydraulic Resistance.
Hood, R Lyle; Kosoglu, Mehmet A; Parker, Matthew; Rylander, Christopher G
2011-09-01
Microneedles have been an expanding medical technology in recent years due to their ability to penetrate tissue and deliver therapy with minimal invasiveness and patient discomfort. Variations in design have allowed for enhanced fluid delivery, biopsy collection, and the measurement of electric potentials. Our novel microneedle design attempts to combine many of these functions into a single length of silica tubing capable of both light and fluid delivery terminating in a sharp tip of less than 100 microns in diameter. This manuscript focuses on the fluid flow aspects of the design, characterizing the contributions to hydraulic resistance from the geometric parameters of the microneedles. Experiments consisted of measuring the volumetric flow rate of de-ionized water at set pressures (ranging from 69-621 kPa) through a relevant range of tubing lengths, needle lengths, and needle tip diameters. Data analysis showed that the silica tubing (~150 micron bore diameter) adhered to within ±5% of the theoretical prediction by Poiseuille's Law describing laminar internal pipe flow at Reynolds numbers less than 700. High hydraulic resistance within the microneedles correlated with decreasing tip diameter. The hydraulic resistance offered by the silica tubing preceding the microneedle taper was approximately 1-2 orders of magnitude less per unit length, but remained the dominating resistance in most experiments as the tubing length was >30 mm. These findings will be incorporated into future design permutations to produce a microneedle capable of both efficient fluid transfer and light delivery.
Efficient global optimization of a limited parameter antenna design
NASA Astrophysics Data System (ADS)
O'Donnell, Teresa H.; Southall, Hugh L.; Kaanta, Bryan
2008-04-01
Efficient Global Optimization (EGO) is a competent evolutionary algorithm suited for problems with limited design parameters and expensive cost functions. Many electromagnetics problems, including some antenna designs, fall into this class, as complex electromagnetics simulations can take substantial computational effort. This makes simple evolutionary algorithms such as genetic algorithms or particle swarms very time-consuming for design optimization, as many iterations of large populations are usually required. When physical experiments are necessary to perform tradeoffs or determine effects which may not be simulated, use of these algorithms is simply not practical at all due to the large numbers of measurements required. In this paper we first present a brief introduction to the EGO algorithm. We then present the parasitic superdirective two-element array design problem and results obtained by applying EGO to obtain the optimal element separation and operating frequency to maximize the array directivity. We compare these results to both the optimal solution and results obtained by performing a similar optimization using the Nelder-Mead downhill simplex method. Our results indicate that, unlike the Nelder-Mead algorithm, the EGO algorithm did not become stuck in local minima but rather found the area of the correct global minimum. However, our implementation did not always drill down into the precise minimum and the addition of a local search technique seems to be indicated.
NASA Astrophysics Data System (ADS)
Lipian, Michał; Karczewski, Maciej; Olasek, Krzysztof
2015-08-01
The Diffuser Augmented Wind Turbine (DAWT) is an innovative mean to increase the power harvested by wind turbine. By encompassing the rotor with a diffusershaped duct it is possible to increase the flow speed through the turbine by about 40-50%. The study presents the development of a numerical model and its validation by the experiments performed in the wind tunnel of the Institute of Turbomachinery, TUL. Then, the numerical model is used for the geometry sensitivity study to optimize the shape of a diffuser. The paper presents that the DAWT technology has the potential to even double the power outcome of wind turbine when compared to a bare rotor version.
Parameter uncertainties in the design and optimization of cantilever piezoelectric energy harvesters
NASA Astrophysics Data System (ADS)
Franco, V. R.; Varoto, P. S.
2017-09-01
A crucial issue in piezoelectric energy harvesting is the efficiency of the mechanical to electrical conversion process. Several techniques have been investigated in order to obtain a set of optimum design parameters that will lead to the best performance of the harvester in terms of electrical power generation. Once an optimum design is reached it is also important to consider uncertainties in the selected parameters that in turn can lead to loss of performance in the energy conversion process. The main goal of this paper is to perform a comprehensive discussion of the effects of multi-parameter aleatory uncertainties on the performance and design optimization of a given energy harvesting system. For that, a typical energy harvester consisting of a cantilever beam carrying a tip mass and partially covered by piezoelectric layers on top and bottom surfaces is considered. A distributed parameter electromechanical modal of the harvesting system is formulated and validated through experimental tests. First, the SQP (Sequential Quadratic Planning) optimization is employed to obtain an optimum set of parameters that will lead to best performance of the harvester. Second, once the optimum harvester configuration is found random perturbations are introduced in the key parameters and Monte Carlo simulations are performed to investigate how these uncertainties propagate and affect the performance of the device studied. Numerically simulated results indicate that small variations in some design parameters can cause a significant variation in the output electrical power, what strongly suggests that uncertainties must be accounted for in the design of beam energy harvesting systems.
Lim, Hyun Ja; Hoffmann, Raymond G
2007-01-01
In biomedical research, meaningful conclusions can only be drawn based on data collected from a valid scientific design using appropriate statistical methods. Therefore, the selection of an appropriate study design is important in order to provide an unbiased and scientific evaluation of the research questions. In this chapter, the different kinds of experimental studies commonly used in biology and medicine are introduced. A brief survey of basic experimental study designs, randomization, blinding, possible biases, issues in data analysis, and interpretation of the study results are mainly provided.
Cold-Crucible Design Parameters for Next Generation HLW Melters
Gombert, D.; Richardson, J.; Aloy, A.; Day, D.
2002-02-26
The cold-crucible induction melter (CCIM) design eliminates many materials and operating constraints inherent in joule-heated melter (JHM) technology, which is the standard for vitrification of high-activity wastes worldwide. The cold-crucible design is smaller, less expensive, and generates much less waste for ultimate disposal. It should also allow a much more flexible operating envelope, which will be crucial if the heterogeneous wastes at the DOE reprocessing sites are to be vitrified. A joule-heated melter operates by passing current between water-cooled electrodes through a molten pool in a refractory-lined chamber. This design is inherently limited by susceptibility of materials to corrosion and melting. In addition, redox conditions and free metal content have exacerbated materials problems or lead to electrical short-circuiting causing failures in DOE melters. In contrast, the CCIM design is based on inductive coupling of a water-cooled high-frequency electrical coil with the glass, causing eddycurrents that produce heat and mixing. A critical difference is that inductance coupling transfers energy through a nonconductive solid layer of slag coating the metal container inside the coil, whereas the jouleheated design relies on passing current through conductive molten glass in direct contact with the metal electrodes and ceramic refractories. The frozen slag in the CCIM design protects the containment and eliminates the need for refractory, while the corrosive molten glass can be the limiting factor in the JH melter design. The CCIM design also eliminates the need for electrodes that typically limit operating temperature to below 1200 degrees C. While significant marketing claims have been made by French and Russian technology suppliers and developers, little data is available for engineering and economic evaluation of the technology, and no facilities are available in the US to support testing. A currently funded project at the Idaho National Engineering
Williams, Bryan; Cockcroft, John R; Kario, Kazuomi; Zappe, Dion H; Cardenas, Pamela; Hester, Allen; Brunel, Patrick; Zhang, Jack
2014-01-01
Introduction Hypertension in elderly people is characterised by elevated systolic blood pressure (SBP) and increased pulse pressure (PP), which indicate large artery ageing and stiffness. LCZ696, a first-in-class angiotensin receptor neprilysin inhibitor (ARNI), is being developed to treat hypertension and heart failure. The Prospective comparison of Angiotensin Receptor neprilysin inhibitor with Angiotensin receptor blocker MEasuring arterial sTiffness in the eldERly (PARAMETER) study will assess the efficacy of LCZ696 versus olmesartan on aortic stiffness and central aortic haemodynamics. Methods and analysis In this 52-week multicentre study, patients with hypertension aged ≥60 years with a mean sitting (ms) SBP ≥150 to <180 and a PP>60 mm Hg will be randomised to once daily LCZ696 200 mg or olmesartan 20 mg for 4 weeks, followed by a forced-titration to double the initial doses for the next 8 weeks. At 12–24 weeks, if the BP target has not been attained (msSBP <140 and ms diastolic BP <90 mm Hg), amlodipine (2.5–5 mg) and subsequently hydrochlorothiazide (6.25–25 mg) can be added. The primary and secondary endpoints are changes from baseline in central aortic systolic pressure (CASP) and central aortic PP (CAPP) at week 12, respectively. Other secondary endpoints are the changes in CASP and CAPP at week 52. A sample size of 432 randomised patients is estimated to ensure a power of 90% to assess the superiority of LCZ696 over olmesartan at week 12 in the change from baseline of mean CASP, assuming an SD of 19 mm Hg, the difference of 6.5 mm Hg and a 15% dropout rate. The primary variable will be analysed using a two-way analysis of covariance. Ethics and dissemination The study was initiated in December 2012 and final results are expected in 2015. The results of this study will impact the design of future phase III studies assessing cardiovascular protection. Clinical trials identifier EUDract number 2012
Xue, Dingyü; Li, Tingxue
2017-04-27
The parameter optimization method for multivariable systems is extended to the controller design problems for multiple input multiple output (MIMO) square fractional-order plants. The algorithm can be applied to search for the optimal parameters of integer-order controllers for fractional-order plants with or without time delays. Two examples are given to present the controller design procedures for MIMO fractional-order systems. Simulation studies show that the integer-order controllers designed are robust to plant gain variations. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.
NASA Technical Reports Server (NTRS)
Vanspeybroeck, L.; Antrim, W.; Boyd, D.; Giacconi, R.; Sinnamon, G.; Stille, F.
1972-01-01
The final report for the large orbiting X-ray telescope (LOXT) high resolution mirror design study is presented. The following tasks were performed: (1) Generation of a reference and alternate preliminary design for the LOXT high resolution mirror assembly, which will meet the LOXT scientific requirements, and are within the present state of the art of materials and fabrication techniques. (2) Measurement, in X-rays, of the scattering properties of a variety of optical flats, embodying materials, coatings, and polishing techniques which might be applicable to the flight configuration LOXT high resolution mirror. (3) Preparation of a procurement specification for a paraboloid test mirror of the size of the innermost paraboloid of the high resolution mirror assembly, including the design requirements for the reference design evolved from this preliminary design study. The results of the engineering and scientific analysis and the conclusions drawn are presented. The procurement specification for the test mirror is included.
Multiobjective optimization in structural design with uncertain parameters and stochastic processes
NASA Technical Reports Server (NTRS)
Rao, S. S.
1984-01-01
The application of multiobjective optimization techniques to structural design problems involving uncertain parameters and random processes is studied. The design of a cantilever beam with a tip mass subjected to a stochastic base excitation is considered for illustration. Several of the problem parameters are assumed to be random variables and the structural mass, fatigue damage, and negative of natural frequency of vibration are considered for minimization. The solution of this three-criteria design problem is found by using global criterion, utility function, game theory, goal programming, goal attainment, bounded objective function, and lexicographic methods. It is observed that the game theory approach is superior in finding a better optimum solution, assuming the proper balance of the various objective functions. The procedures used in the present investigation are expected to be useful in the design of general dynamic systems involving uncertain parameters, stochastic process, and multiple objectives.
NASA Technical Reports Server (NTRS)
Howell, Leonard W.; Whitaker, Ann F. (Technical Monitor)
2001-01-01
The maximum likelihood procedure is developed for estimating the three spectral parameters of an assumed broken power law energy spectrum from simulated detector responses and their statistical properties investigated. The estimation procedure is then generalized for application to real cosmic-ray data. To illustrate the procedure and its utility, analytical methods were developed in conjunction with a Monte Carlo simulation to explore the combination of the expected cosmic-ray environment with a generic space-based detector and its planned life cycle, allowing us to explore various detector features and their subsequent influence on estimating the spectral parameters. This study permits instrument developers to make important trade studies in design parameters as a function of the science objectives, which is particularly important for space-based detectors where physical parameters, such as dimension and weight, impose rigorous practical limits to the design envelope.
Kurzke, J.
1999-01-01
In gas turbine performance simulations often the following question arises: what is the best thermodynamic cycle design point? This is an optimization task which can be attacked in two ways. One can do a series of parameter variations and pick from the resulting graphs the best solution or one can employ numerical optimization algorithms that produce a single cycle that fulfills all constraints. The conventional parameter study builds strongly on the engineering judgment and gives useful information over a range of parameter selections. However, when values for more than a few variables have to be determined while several constraints are existing, then numerical optimization routines can help to find the mathematical optimum faster and more accurately. Sometimes even an outstanding solution is found which was overlooked while doing a preliminary parameter study. For any simulation task a sophisticated graphical user interface is of great benefit. This is especially true for automated numerical optimizations. It is quite helpful to see on the screen of a PC how the variables are changing and which constraints are limiting the design. A quick and clear graphical representation of trade studies is also of great advantage. The paper describes how numerical optimization and parameter studies are implemented in a Windows-based PC program. As an example, the cycle selection of a derivative turbofan engine with a given core shows the merits of numerical optimization. The parameter variation is best suited for presenting the sensitivity of the result in the neighborhood of the optimum cycle design point.
Vibroacoustic test plan evaluation: Parameter variation study
NASA Technical Reports Server (NTRS)
Stahle, C. V.; Gongloef, H. R.
1976-01-01
Statistical decision models are shown to provide a viable method of evaluating the cost effectiveness of alternate vibroacoustic test plans and the associated test levels. The methodology developed provides a major step toward the development of a realistic tool to quantitatively tailor test programs to specific payloads. Testing is considered at the no test, component, subassembly, or system level of assembly. Component redundancy and partial loss of flight data are considered. Most and probabilistic costs are considered, and incipient failures resulting from ground tests are treated. Optimums defining both component and assembly test levels are indicated for the modified test plans considered. modeling simplifications must be considered in interpreting the results relative to a particular payload. New parameters introduced were a no test option, flight by flight failure probabilities, and a cost to design components for higher vibration requirements. Parameters varied were the shuttle payload bay internal acoustic environment, the STS launch cost, the component retest/repair cost, and the amount of redundancy in the housekeeping section of the payload reliability model.
Study of Nightitme enhancement of ionospheric parameters
NASA Astrophysics Data System (ADS)
Sardar, Nuzhat
2012-07-01
In the present work ionospheric electron content (IEC) as well as critical frequency of F2-layer (foF2) data from three locations (low, mid and high) latitudes have been used to study the anomalous nighttime F-region during low to moderate solar activity period i.e. from January 2006 to December 2010. Our results show that at high and mid latitude locations percentage of enhancement with IEC and foF2 is maximum during winter, whereas at low latitude location maximum percentage of enhancement with both the parameters is maximum during equinox. Out of 1176 number of enhancements for IEC, 661 enhancements occurred during pre-midnight hours and 515 occurred during post-midnight hours. Although for foF2 parameter out of 948 enhancements, 457 enhancements occurred during pre-midnight hours and 491 enhancements occurred during post-midnight hours.
A Comparison of Parameter Study Creation and Job Submission Tools
NASA Technical Reports Server (NTRS)
DeVivo, Adrian; Yarrow, Maurice; McCann, Karen M.; Biegel, Bryan (Technical Monitor)
2001-01-01
We consider the differences between the available general purpose parameter study and job submission tools. These tools necessarily share many features, but frequently with differences in the way they are designed and implemented For this class of features, we will only briefly outline the essential differences. However we will focus on the unique features which distinguish the ILab parameter study and job submission tool from other packages, and which make the ILab tool easier and more suitable for use in our research and engineering environment.
Calibration of Discrete Element Heat Transfer Parameters by Central Composite Design
NASA Astrophysics Data System (ADS)
Deng, Zongquan; Cui, Jinsheng; Hou, Xuyan; Jiang, Shengyuan
2017-03-01
The efficiency and precision of parameter calibration in discrete element method (DEM) are not satisfactory, and parameter calibration for granular heat transfer is rarely involved. Accordingly, parameter calibration for granular heat transfer with the DEM is studied. The heat transfer in granular assemblies is simulated with DEM, and the effective thermal conductivity (ETC) of these granular assemblies is measured with the transient method in simulations. The measurement testbed is designed to test the ETC of the granular assemblies under normal pressure and a vacuum based on the steady method. Central composite design (CCD) is used to simulate the impact of the DEM parameters on the ETC of granular assemblies, and the heat transfer parameters are calibrated and compared with experimental data. The results show that, within the scope of the considered parameters, the ETC of the granular assemblies increases with an increasing particle thermal conductivity and decreases with an increasing particle shear modulus and particle diameter. The particle thermal conductivity has the greatest impact on the ETC of granular assemblies followed by the particle shear modulus and then the particle diameter. The calibration results show good agreement with the experimental results. The error is less than 4%, which is within a reasonable range for the scope of the CCD parameters. The proposed research provides high efficiency and high accuracy parameter calibration for granular heat transfer in DEM.
NASA Astrophysics Data System (ADS)
Belwanshi, Vinod; Topkar, Anita
2016-05-01
Finite element analysis study has been carried out to optimize the design parameters for bulk micro-machined silicon membranes for piezoresistive pressure sensing applications. The design is targeted for measurement of pressure up to 200 bar for nuclear reactor applications. The mechanical behavior of bulk micro-machined silicon membranes in terms of deflection and stress generation has been simulated. Based on the simulation results, optimization of the membrane design parameters in terms of length, width and thickness has been carried out. Subsequent to optimization of membrane geometrical parameters, the dimensions and location of the high stress concentration region for implantation of piezoresistors have been obtained for sensing of pressure using piezoresistive sensing technique.
Belwanshi, Vinod; Topkar, Anita
2016-05-23
Finite element analysis study has been carried out to optimize the design parameters for bulk micro-machined silicon membranes for piezoresistive pressure sensing applications. The design is targeted for measurement of pressure up to 200 bar for nuclear reactor applications. The mechanical behavior of bulk micro-machined silicon membranes in terms of deflection and stress generation has been simulated. Based on the simulation results, optimization of the membrane design parameters in terms of length, width and thickness has been carried out. Subsequent to optimization of membrane geometrical parameters, the dimensions and location of the high stress concentration region for implantation of piezoresistors have been obtained for sensing of pressure using piezoresistive sensing technique.
A PARAMETER STUDY FOR BAROCLINIC VORTEX AMPLIFICATION
Raettig, Natalie; Klahr, Hubert; Lyra, Wladimir E-mail: klahr@mpia.de
2013-03-10
Recent studies have shown that baroclinic vortex amplification is strongly dependent on certain factors, namely, the global entropy gradient, the efficiency of thermal diffusion and/or relaxation as well as numerical resolution. We conduct a comprehensive study of a broad range and combination of various entropy gradients, thermal diffusion and thermal relaxation timescales via local shearing sheet simulations covering the parameter space relevant for protoplanetary disks. We measure the Reynolds stresses as a function of our control parameters and see that there is angular momentum transport even for entropy gradients as low as {beta} = -dln s/dln r = 1/2. Values we expect in protoplanetary disks are between {beta} = 0.5-2.0 The amplification-rate of the perturbations, {Gamma}, appears to be proportional to {beta}{sup 2} and thus proportional to the square of the Brunt-Vaeisaelae frequency ({Gamma}{proportional_to}{beta}{sup 2}{proportional_to}N {sup 2}). The saturation level of Reynolds stresses, on the other hand, seems to be proportional to {beta}{sup 1/2}. This highlights the importance of baroclinic effects even for the low entropy gradients expected in protoplanetary disks.
Effects of toothless stator design on dynamic model parameters of permanent magnet generators
Arkadan, A.A.; Vyas, R. . Electrical and Computer Engineering Dept.)
1993-06-01
The effects of toothless stator design on the dynamic model parameters of permanent magnet (PM) generators are presented. These parameters which include inductances and induced back emfs are determines for a 75 kVA, 208 V, 400 Hz, two-pole, permanent magnet generator. Two particular stator designs, a toothless stator and a conventional type stator (with iron teeth), are considered. The method which is used to determine these parameters is general in nature and is based on the use of a series of magnetic field solutions. A validation of the computed emf and inductance values based on experimentally obtained data is given in the paper. The results of using these parameters in a state space model in the abc frame of reference to study the effects of a toothless stator design on the PM generator synchronous inductances are presented. Based on that, it is demonstrated that the effects of rotor saliency and armature loading on the machine parameters are minimized in the case of the toothless design.
NASA Technical Reports Server (NTRS)
Howell, Leonard W.
2002-01-01
The method of Maximum Likelihood (ML) is used to estimate the spectral parameters of an assumed broken power law energy spectrum from simulated detector responses. This methodology, which requires the complete specificity of all cosmic-ray detector design parameters, is shown to provide approximately unbiased, minimum variance, and normally distributed spectra information for events detected by an instrument having a wide range of commonly used detector response functions. The ML procedure, coupled with the simulated performance of a proposed space-based detector and its planned life cycle, has proved to be of significant value in the design phase of a new science instrument. The procedure helped make important trade studies in design parameters as a function of the science objectives, which is particularly important for space-based detectors where physical parameters, such as dimension and weight, impose rigorous practical limits to the design envelope. This ML methodology is then generalized to estimate broken power law spectral parameters from real cosmic-ray data sets.
CVD parameter study using strategy of experimentation
Williams, R.E.
1984-07-01
An experimental design strategy was used to determine the operating characteristics of an apparatus for forming tungsten-rhenium (W-Re) alloys by chemical vapor deposition. The metal deposits were made at 650/sup 0/C by the hydrogen reduction of a 10 percent rhenium hexafluoride and 90 percent gas mixture at 0.66 to 4.00 kPa (5 to 30 torr). Hydrogen flow rates ranged from 550 to 2770 ..mu..mol/s and mixed metal fluoride flows ranged from 41 to 130 ..mu..mol/s. An operating point was sought that would produce a high strength alloy, so the deposition results were fit by least squares regression to second order response equations. Seven properties were measured: deposition rate, average composition, maximum composition, minimum composition, sample standard deviation of the composition, microhardness as a measure of the amount of A15 phase, and as-deposited surface quality. A set of operating parameters was determined that was predicted to yield a 23 w/o Re alloy with an 1100 DPH (diamond pyramid hardness) microhardness.
[Psychological study of parameter selection for Chinese speech warning].
Han, D; Zhou, C; Liu, Y; Zhai, Y
1998-06-01
To study the effects of the parameters of Chinese speech warning on cognitive property, and to obtain the optimal parameters in accordance with cognitive property, experiments of cognitive property for Chinese speech warning was carried out in 20 healthy males. Combining our study on the sensation-reaction time, the optimal parameters in accordance with space ergonomics [correction of ergonormics] and cognitive property were determined: suitable time length of prewarning sound is 0.35 approximately 0.55 s; prewarning interval is 0.3-0.4 s; interval between sentences is 0.3-0.4 s; word number of warning sentence < or = 7. The result can serve as the objective ergonomical basis for the design of Chinese speech warning system in manned space vehicle, and as the evaluation criterion.
An empirical study of scanner system parameters
NASA Technical Reports Server (NTRS)
Landgrebe, D.; Biehl, L.; Simmons, W.
1976-01-01
The selection of the current combination of parametric values (instantaneous field of view, number and location of spectral bands, signal-to-noise ratio, etc.) of a multispectral scanner is a complex problem due to the strong interrelationship these parameters have with one another. The study was done with the proposed scanner known as Thematic Mapper in mind. Since an adequate theoretical procedure for this problem has apparently not yet been devised, an empirical simulation approach was used with candidate parameter values selected by the heuristic means. The results obtained using a conventional maximum likelihood pixel classifier suggest that although the classification accuracy declines slightly as the IFOV is decreased this is more than made up by an improved mensuration accuracy. Further, the use of a classifier involving both spatial and spectral features shows a very substantial tendency to resist degradation as the signal-to-noise ratio is decreased. And finally, further evidence is provided of the importance of having at least one spectral band in each of the major available portions of the optical spectrum.
AEROSOL PARTICLE COLLECTOR DESIGN STUDY
Lee, S; Richard Dimenna, R
2007-09-27
A computational evaluation of a particle collector design was performed to evaluate the behavior of aerosol particles in a fast flowing gas stream. The objective of the work was to improve the collection efficiency of the device while maintaining a minimum specified air throughput, nominal collector size, and minimal power requirements. The impact of a range of parameters was considered subject to constraints on gas flow rate, overall collector dimensions, and power limitations. Potential improvements were identified, some of which have already been implemented. Other more complex changes were identified and are described here for further consideration. In addition, fruitful areas for further study are proposed.
Study Design for Sequencing Studies.
Honaas, Loren A; Altman, Naomi S; Krzywinski, Martin
2016-01-01
Once a biochemical method has been devised to sample RNA or DNA of interest, sequencing can be used to identify the sampled molecules with high fidelity and low bias. High-throughput sequencing has therefore become the primary data acquisition method for many genomics studies and is being used more and more to address molecular biology questions. By applying principles of statistical experimental design, sequencing experiments can be made more sensitive to the effects under study as well as more biologically sound, hence more replicable.
Design of nonlinear discrete-time controllers using a parameter space sampling procedure
NASA Technical Reports Server (NTRS)
Young, G. E.; Auslander, D. M.
1983-01-01
The design of nonlinear discrete-time controllers is investigated where the control algorithm assumes a special form. State-dependent control actions are obtained from tables whose values are the design parameters. A new design methodology capable of dealing with nonlinear systems containing parameter uncertainty is used to obtain the controller design. Various controller strategies are presented and illustrated through an example.
Understanding facilities design parameters for a remanufacturing system
NASA Astrophysics Data System (ADS)
Topcu, Aysegul; Cullinane, Thomas
2005-11-01
Remanufacturing is rapidly becoming a very important element in the economies of the world. Products such as washing machines, clothes driers, automobile parts, cell phones and a wide range of consumer durable goods are being reclaimed and sent through processes that restore these products to levels of operating performance that are as good or better than their new product performance. The operations involved in the remanufacturing process add several new dimensions to the work that must be performed. Disassembly is an operation that rarely appears on the operations chart of a typical production facility. The inspection and test functions in remanufacturing most often involve several more tasks than those involved in the first time manufacturing cycle. A close evaluation of most any remanufacturing operation reveals several points in the process in which parts must be cleaned, tested and stored. Although several researchers have focused their work on optimizing the disassembly function and the inspection, test and store functions, very little research has been devoted to studying the impact of the facilities design on the effectiveness of the remanufacturing process. The purpose of this paper will be to delineate the differences between first time manufacturing operations and remanufacturing operations for durable goods and to identify the features of the facilities design that must be considered if the remanufacturing operations are to be effective.
A design method for minimizing sensitivity to plant parameter variations
NASA Technical Reports Server (NTRS)
Hadass, Z.; Powell, J. D.
1974-01-01
A method is described for minimizing the sensitivity of multivariable systems to parameter variations. The variable parameters are considered as random variables and their effect is included in a quadratic performance index. The performance index is a weighted sum of the state and control covariances that stem from both the random system disturbances and the parameter uncertainties. The numerical solution of the problem is described and application of the method to several initially sensitive tracking systems is discussed. The sensitivity factor of reduction was typically 2 or 3 over a system based on random system noise only, and yet resulted in state RMS increases of only about a factor of two.
Sensitivity of optimum solutions to problem parameters. [in aircraft design
NASA Technical Reports Server (NTRS)
Sobieszczanski-Sobieski, J.; Riley, K. M.; Barthelemy, J.-F.
1981-01-01
In an aircraft configuration optimization, the information of interest is the sensitivity of optimal block fuel consumption and wing aspect ratio and area, to variations of required range and payload. The objectives of this study are: (1) to show how the equations capable of yielding the sensitivity derivatives (the sensitivity equations) can be obtained for a constrained optimum regardless of the type of optimization algorithm that was used to arrive at the optimum point, (2) to review the solvability of the sensitivity equations and (3) to report on applications on structural optimization. Numerical examples, which demonstrate the sensitivity analysis, include a tubular column and a three-bar truss for which closed form solutions are obtained, a ten-bar truss that requires the use of a finite element analysis, and a thin-walled beam characterized by strongly nonlinear constraints for local buckling. It is concluded that a practically significant extrapolation accuracy may be obtained for a reasonably broad range of parameter changes; and that accuracy does not depend strongly on the degree of convergence of the optimum solution from which the sensitivity derivatives are obtained.
NASA Astrophysics Data System (ADS)
Jung, Ha Kyu; Kwon, Won Tae; Lee, Soo-Il
2007-12-01
Thermosonic flip chip bonding is an important technology for the electronic packaging due to its simplicity, cost effectiveness and clean and dry process. Mechanical properties of the horn and the shank, such as the natural frequency and the amplitude, have a great effect on the bonding capability of the transverse flip chip bonding system. In this study, an endeavor has been made to design the horn and shank as an assembly. A commercial FEM software (ANSYS) is used to analyze the system. New design of the clamp to hold the horn at the nodal point is also introduced. The clamp with a bent shape is newly designed. It shows the ability to increase the amplitude of the vibration at the end of the horn compared with the straight-cylindrical-type-clamp. For the optimal design of the horn-shank assembly system, it is studied the effect of the design parameters and the tolerance on the vibration amplitude and planarity at the end of the shank. The variation of the design parameters and the tolerance changes the amplitude and the frequency of the vibration of the shank. They, in turn, have an effect on the quantity of the plastic deformation of the gold ball bump, which determined the quality of the flip chip bonding. The design and tolerance parameters that give the great effect on the amplitude of the shank are determined using Taguchi's method. Error of set-up angle, the length and diameter of horn and error of the length of the shank are determined to be the parameters that have great effect on the amplitude of the system.
NASA Astrophysics Data System (ADS)
Tokunaga, Yoshitaka
This paper presents estimation techniques of machine parameters for power transformer using design procedure of transformer and genetic algorithm with real coding. Especially, it is very difficult to obtain machine parameters for transformers in customers' facilities. Using estimation techniques, machine parameters could be calculated from the only nameplate data of these transformers. Subsequently, EMTP-ATP simulation of the inrush current was carried out using machine parameters estimated by techniques developed in this study and simulation results were reproduced measured waveforms.
Meteorologic parameters and migraine headache: ED study.
Yilmaz, Mustafa; Gurger, Mehtap; Atescelik, Metin; Yildiz, Mustafa; Gurbuz, Sukru
2015-03-01
Migraine is common in society and is one of the primary causes of chronic headache with episodes. In this study, we aimed to determine the role of meteorologic parameters and moon phase on triggering migraine attacks and effects on the number of patients presenting to the emergency department with migraine headaches. Patients admitted to the emergency department due to a migraine headache during a 1-year period were studied retrospectively. Correlation between moon phases, pressure, temperature, humidity, wind speed values of meteorologic observation, and recording station located in the same city and daily number of patients was analyzed. A total of 3491 patients, of whom 72% (n = 2518) were women, were enrolled. The average daily number of patients was 9.6 ± 4 (3-24). A statistically significant correlation was found between the number of daily patients and daily maximum temperature (P = .005), mean temperature (P = .013), minimum temperature (P = .041), and daily temperature change (P = .003). In addition, a negative correlation was found between the daily number of patients presenting to the emergency department and daily relative humidity (in percentage; P = .031). No significant relationship was found between moon phases and the number of patients. We have determined that the number of patients admitted to the emergency department with migraine headache has increased with high temperature and low humidity and that there is no relationship between the number of patients and moon phases. Copyright © 2014 Elsevier Inc. All rights reserved.
Fox, J.M.; Degen, B.D.; Cady, G.; Deslate, F.D.; Summers, R.L. ); Akgerman, A. ); Smith, J.M. )
1990-06-01
The objective of these studies was to perform a realistic evaluation of the relative costs of tublar-fixed-bed and slurry reactors for methanol, mixed alcohols and Fischer-Tropsch syntheses under conditions where they would realistically be expected to operate. The slurry Fischer-Tropsch reactor was, therefore, operated at low H{sub 2}/CO ratio on gas directly from a Shell gasifier. The fixed-bed reactor was operated on 2.0 H{sub 2}/CO ratio gas after adjustment by shift and CO{sub 2} removal. Every attempt was made to give each reactor the benefit of its optimum design condition and correlations were developed to extend the models beyond the range of the experimental pilot plant data. For the methanol design, comparisons were made for a recycle plant with high methanol yield, this being the standard design condition. It is recognized that this is not necessarily the optimum application for the slurry reactor, which is being proposed for a once-through operation, coproducing methanol and power. Consideration is also given to the applicability of the slurry reactor to mixed alcohols, based on conditions provided by Lurgi for an Octamix{trademark} plant using their standard tubular-fixed reactor technology. 7 figs., 26 tabs.
Numerical investigation of design and operational parameters on CHI spheromak performance
NASA Astrophysics Data System (ADS)
O'Bryan, J. B.; Romero-Talamas, C. A.; Woodruff, S.
2016-10-01
Nonlinear, extended-MHD computation with the NIMROD code is used to explore magnetic self-organization and performance with respect to externally controllable parameters in spheromaks formed with coaxial helicity injection. The goal of this study is to inform the design and operational parameters of proposed proof-of-principle spheromak experiment. The calculations explore multiple distinct phases of evolution (including adiabatic magnetic compression), which must be explored and optimized separately. Results indicate that modest changes to the design and operation of past experiments, e.g. SSPX [E.B. Hooper et al. PPCF 2012], could have significantly improved the plasma-current injector coupling efficiency and performance, particularly with respect to peak temperature and lifetime. Though we frequently characterize performance relative to SSPX, we are also exploring fundamentally different designs and modes of operation, e.g. flux compression. This work is supported by DAPRA under Grant No. N66001-14-1-4044.
Shuttle communications design study
NASA Technical Reports Server (NTRS)
Cartier, D. E.
1975-01-01
The design and development of a space shuttle communication system are discussed. The subjects considered include the following: (1) Ku-band satellite relay to shuttle, (2) phased arrays, (3) PN acquisition, (4) quadriplexing of direct link ranging and telemetry, (5) communications blackout on launch and reentry, (6) acquisition after blackout on reentry, (7) wideband communications interface with the Ku-Band rendezvous radar, (8) aeroflight capabilities of the space shuttle, (9) a triple multiplexing scheme equivalent to interplex, and (10) a study of staggered quadriphase for use on the space shuttle.
Seal design alternatives study
Van Sambeek, L.L.
1993-06-01
This report presents the results from a study of various sealing alternatives for the WIPP sealing system. Overall, the sealing system has the purpose of reducing to the extent possible the potential for fluids (either gas or liquid) from entering or leaving the repository. The sealing system is divided into three subsystems: drift and panel seals within the repository horizon, shaft seals in each of the four shafts, and borehole seals. Alternatives to the baseline configuration for the WIPP seal system design included evaluating different geometries and schedules for seal component installations and the use of different materials for seal components. Order-of-magnitude costs for the various alternatives were prepared as part of the study. Firm recommendations are not presented, but the advantages and disadvantages of the alternatives are discussed. Technical information deficiencies are identified and studies are outlined which can provide required information.
NASA Astrophysics Data System (ADS)
Penta, Francesco; Rossi, Cesare; Savino, Sergio
2016-06-01
This study aims to optimize the geometrical parameters of an under-actuated mechanical finger by conducting a theoretical analysis of these parameters. The finger is actuated by a flexion tendon and an extension tendon. The considered parameters are the tendon guide positions with respect to the hinges. By applying such an optimization, the correct kinematical and dynamical behavior of the closing cycle of the finger can be obtained. The results of this study are useful for avoiding the snapthrough and the single joint hyperflexion, which are the two breakdowns most frequently observed during experimentation on prototypes. Diagrams are established to identify the optimum values for the tendon guides position of a finger with specified dimensions. The findings of this study can serve as guide for future finger design.
Design parameters and source terms: Volume 2, Source terms: Revision 0
Not Available
1987-09-01
The Design Parameters and Source Terms Document was prepared in accordance with DOE request and to provide data for the environmental impact study to be performed in the future for the Deaf Smith County, Texas site for a nuclear waste repository in salt. This document updates a previous unpublished report to the level of the Site Characterization Plan---Conceptual Design Report SCP-CDR. The previous study identifies the data needs for the Environmental Assessment effort for seven possible salt repository sites. Volume 2 contains tables of source terms.
Design parameters and source terms: Volume 3, Source terms: Revision 0
Not Available
1987-09-01
The Design Parameters and Source Terms Document was prepared in accordance with DOE request and to provide data for the environmental impact study to be performed in the future for the Deaf Smith County, Texas site for a nuclear waste repository in salt. This document updates a previous unpublished report to the level of the Site Characterization Plan /endash/ Conceptual Design Report, SCP-CDR. The previous unpublished SCC Study identifies the data needs for the Environmental Assessment effort for seven possible salt repository sites.
Tropospheric range error parameters: Further studies
NASA Technical Reports Server (NTRS)
Hopfield, H. S.
1972-01-01
Improved parameters are presented for predicting the tropospheric effect on electromagnetic range measurements from surface meteorological data. More geographic locations have been added to the earlier list. Parameters are given for computing the dry component of the zenith radio range effect from surface pressure alone with an rms error of 1 to 2 mm, or the total range effect from the dry and wet components of the surface refractivity and a two-part quartic profile model. The new parameters are obtained, as before, from meteorological balloon data but with improved procedures, including the conversion of the geopotential heights of the balloon data to actual or geometric heights before using the data. The revised values of the parameter k (dry component of vertical radio range effect per unit pressure at the surface) show more latitude variation than is accounted for by the variation of g, the acceleration of gravity.
Tropospheric range error parameters: Further studies
NASA Technical Reports Server (NTRS)
Hopfield, H. S.
1972-01-01
Improved parameters are presented for predicting the tropospheric effect on electromagnetic range measurements from surface meteorological data. Parameters are given for computing the dry component of the zenith radio range effect from surface pressure alone with an rms error of 1 to 2 mm, or the total range effect from the dry and wet components of the surface refractivity, N, and a two-part quartic profile model. The parameters were obtained from meteorological balloon data with improved procedures, including the conversion of the geopotential heights of the balloon data to actual or geometric heights before using the data. The revised values of the parameter k show more latitude variation than is accounted for by the variation of g. This excess variation of k indicates a small latitude variation in the mean molecular weight of air and yields information about the latitude-varying water vapor content of air.
Vertical Axis Wind Turbine Foundation parameter study
Lodde, P.F.
1980-07-01
The dynamic failure criterion governing the dimensions of prototype Vertical Axis Wind Turbine Foundations is treated as a variable parameter. The resulting change in foundation dimensions and costs is examined.
Design parameters of a solar-driven heat engine
Goektun, S.
1996-01-01
Maximum power and efficiency are treated at the maximum power output of an internally and externally irreversible solar-driven power plant heat engine. It was found that the thermal efficiency depends on the cycle-irreversibility parameter must be less than 1.0 for maximum power output.
Influence of Design Parameters on Mechanical Power Losses of Helical Gear Pairs
NASA Astrophysics Data System (ADS)
Li, Sheng; Vaidyanathan, Aarthy; Harianto, Jonny; Kahraman, Ahmet
In this study, the influence of basic design parameters and tooth surface modifications on the mechanical (friction induced) power losses of a helical gear pair is studied. A helical gear mechanical efficiency model based on elastohydrodynamic lubrication (EHL) is introduced. The model is used to simulate the gear contact conditions of an example helical gear pair within the ranges of basic design parameter such as pressure and helix angles, number of teeth (module), and major diameters to quantify their impact on mechanical power losses. Variation of gear efficiency with these parameters are then weighed against other functional requirements such as transmission error amplitudes, and contact and bending stresses to demonstrate that many designs that have high efficiency might perform poorly in terms of noise, pitting, and tooth breakage. A representative design that is acceptable in all aspects is considered next with varying amounts of tooth modifications to demonstrate their impact on power losses. At the end, recommendations are made on how to reduce helical gear mechanical power losses while meeting other functional requirements as well.
NASA Technical Reports Server (NTRS)
Stahara, S. S.
1984-01-01
An investigation was carried out to complete the preliminary development of a combined perturbation/optimization procedure and associated computational code for designing optimized blade-to-blade profiles of turbomachinery blades. The overall purpose of the procedures developed is to provide demonstration of a rapid nonlinear perturbation method for minimizing the computational requirements associated with parametric design studies of turbomachinery flows. The method combines the multiple parameter nonlinear perturbation method, successfully developed in previous phases of this study, with the NASA TSONIC blade-to-blade turbomachinery flow solver, and the COPES-CONMIN optimization procedure into a user's code for designing optimized blade-to-blade surface profiles of turbomachinery blades. Results of several design applications and a documented version of the code together with a user's manual are provided.
Influence of Gear Design Parameters on Gearbox Radiated Noise
NASA Technical Reports Server (NTRS)
Oswald, Fred B.; Townsend, Dennis P.; Valco, Mark J.; Spencer, Robert H.; Drago, Raymond J.; Lenski, Joseph W., Jr.
1994-01-01
Spur and helical gears were tested in the NASA gear-noise rig to compare the noise produced by different gear designs. Sound power measurements were performed under controlled conditions for a matrix of operating conditions. Sound power was computed from near-field acoustic intensity scans taken just above the top surface of the gearbox. Test gears included four spur and five helical gear designs. The gears were designed to be as nearly identical as possible except for deliberate differences in tooth geometry and contact ratio. Test results are presented as a function of the gear design and operating conditions in the form of sound power charts and as narrow-band spectra.
Influence of gear design parameters on gearbox radiated noise
NASA Astrophysics Data System (ADS)
Oswald, Fred B.; Townsend, Dennis P.; Valco, Mark J.; Spencer, Robert H.; Drago, Raymond J.; Lenski, Joseph W., Jr.
1994-03-01
Spur and helical gears were tested in the NASA gear-noise rig to compare the noise produced by different gear designs. Sound power measurements were performed under controlled conditions for a matrix of operating conditions. Sound power was computed from near-field acoustic intensity scans taken just above the top surface of the gearbox. Test gears included four spur and five helical gear designs. The gears were designed to be as nearly identical as possible except for deliberate differences in tooth geometry and contact ratio. Test results are presented as a function of the gear design and operating conditions in the form of sound power charts and as narrow-band spectra.
Feathering instability of spiral arms. II. Parameter study
Lee, Wing-Kit
2014-09-10
We report the results of a parameter study of the feathering stability in the galactic spiral arms. A two-dimensional, razor-thin magnetized self-gravitating gas disk with an imposed two-armed stellar spiral structure is considered. Using the formulation developed previously by Lee and Shu, a linear stability analysis of the spiral shock is performed in a localized Cartesian geometry. Results of the parameter study of the base state with a spiral shock are also presented. The single-mode feathering instability that leads to growing perturbations may explain the feathering phenomenon found in nearby spiral galaxies. The self-gravity of the gas, characterized by its average surface density, is an important parameter that (1) shifts the spiral shock farther downstream and (2) increases the growth rate and decreases the characteristic spacing of the feathering structure due to the instability. On the other hand, while the magnetic field suppresses the velocity fluctuation associated with the feathers, it does not strongly affect their growth rate. Using a set of typical parameters of the grand-design spiral galaxy M51 at 2 kpc from the center, the spacing of the feathers with the maximum growth rate is found to be 530 pc, which agrees with the previous observational studies.
ATW neutronics design studies.
Wade, D. C.; Yang, W. S.; Khalil, H.
2000-11-10
The Accelerator Transmutation of Waste (ATW) concept has been proposed as a transuranics (TRU) (and long-lived fission product) incinerator for processing the 87,000 metric tonnes of Light Water Reactor used fuel which will have been generated by the time the currently deployed fleet of commercial reactors in the US reach the end of their licensed lifetime. The ATW is proposed to separate the uranium from the transuranics and fission products in the LWR used fuel, to fission the transuranics, to send the LWR and ATW generated fission products to the geologic repository and to send the uranium to either a low level waste disposal site or to save it for future use. The heat liberated in fissioning the transuranics would be converted to electricity and sold to partially offset the cost of ATW construction and operations. Options for incineration of long-lived fission products are under evaluation. A six-year science-based program of ATW trade and system studies was initiated in the US FY 2000 to achieve two main purposes: (1) ''to evaluate ATW within the framework of nonproliferation, waste management, and economic considerations,'' and (2) ''to evaluate the efficacy of the numerous technical options for ATW system configuration.'' This paper summarizes the results from neutronics and thermal/hydraulics trade studies which were completed at Argonne National Laboratory during the first year of the program. Core designs were developed for Pb-Bi cooled and Na cooled 840 MW{sub th} fast spectrum transmuter designs employing recycle. Additionally, neutronics analyses were performed at Argonne for a He cooled 600 MW{sub th} hybrid thermal and fast core design proposed by General Atomics Co. which runs critical for 3/4 and subcritical for 1/4 of its four year once-thin burn cycle. The mass flows and the ultimate loss of transuranic isotopes to the waste stream per unit of heat generated during transmutation have been calculated on a consistent basis and are compared. (Long
Effective Parameters on Seismic Design of Rectangular Underground Structures
Amiri, G. Ghodrati; Maddah, N.; Mohebi, B.
2008-07-08
Underground structures are a significant part of the transportation in the modern society and in the seismic zones should withstand against both seismic and static loadings. Embedded structures should conform to ground deformations during the earthquake but almost exact evaluation of structure to ground distortion is critical. Several two-dimensional finite difference models are used to find effective parameters on racking ratio (structure to ground distortion) including flexibility ratio, various cross sections, embedment depth, and Poisson's ratio of soil. Results show that influence of different cross sections, by themselves is negligible but embedment depth in addition to flexibility ratio and Poisson's ratio is known as a consequential parameter. A comparison with pseudo-static method (simplified frame analysis) is also performed. The results show that for a stiffer structure than soil, racking ratio decreases as the depth of burial decreases; on the other hand, shallow and flexible structures can suffer greater distortion than deeper ones up to 30 percents.
Determination of critical anthropometric parameters for design of respirators
You-Hin Liau
1982-12-01
Anthropometric data were collected from 243 workers in a respirator fit-test programme, and an attempt was made to determine a correlation between these data and the Protection Factor obtained from quantitative fit-testing for half-mask respirators. Data were collected for two direct and five indirect facial measurements from front- and side-view slides of test subjects. For analysis, the data were normalized with relevant respirators dimensions (4 brands and 10 sizes). Results of linear regression analysis indicated that correlation coefficients between Protection Factor and anthropometric data (face length, mouth width, face width, nasal root breadth) were, respectively, 0.04, 0.22, 0.30 and 0.04. These correlation coefficients are for white males without facial hair. The analysis showed the 'critical' parameters to be mouth width and face width; however, a person with certain combinations of anthropometric parameters may provide a better correlation with Protection Factor.
Parameter optimization in AQM controller design to support TCP traffic
NASA Astrophysics Data System (ADS)
Yang, Wei; Yang, Oliver W.
2004-09-01
TCP congestion control mechanism has been widely investigated and deployed on Internet in preventing congestion collapse. We would like to employ modern control theory to specify quantitatively the control performance of the TCP communication system. In this paper, we make use of a commonly used performance index called the Integral of the Square of the Error (ISE), which is a quantitative measure to gauge the performance of a control system. By applying the ISE performance index into the Proportional-plus-Integral controller based on Pole Placement (PI_PP controller) for active queue management (AQM) in IP routers, we can further tune the parameters for the controller to achieve an optimum control minimizing control errors. We have analyzed the dynamic model of the TCP congestion control under this ISE, and used OPNET simulation tool to verify the derived optimized parameters of the controllers.
Conceptual design optimization study
NASA Technical Reports Server (NTRS)
Hollowell, S. J.; Beeman, E. R., II; Hiyama, R. M.
1990-01-01
The feasibility of applying multilevel functional decomposition and optimization techniques to conceptual design of advanced fighter aircraft was investigated. Applying the functional decomposition techniques to the conceptual design phase appears to be feasible. The initial implementation of the modified design process will optimize wing design variables. A hybrid approach, combining functional decomposition techniques for generation of aerodynamic and mass properties linear sensitivity derivatives with existing techniques for sizing mission performance and optimization, is proposed.
NASA Technical Reports Server (NTRS)
Unal, Resit; Morris, W. Douglas; White, Nancy H.; Lepsch, Roger A.
2004-01-01
This paper describes the development of a methodology for estimating reliability and maintainability distribution parameters for a reusable launch vehicle. A disciplinary analysis code and experimental designs are used to construct approximation models for performance characteristics. These models are then used in a simulation study to estimate performance characteristic distributions efficiently. The effectiveness and limitations of the developed methodology for launch vehicle operations simulations are also discussed.
NASA Technical Reports Server (NTRS)
Unal, Resit; Morris, W. Douglas; White, Nancy H.; Lepsch, Roger A.
2004-01-01
This paper describes the development of a methodology for estimating reliability and maintainability distribution parameters for a reusable launch vehicle. A disciplinary analysis code and experimental designs are used to construct approximation models for performance characteristics. These models are then used in a simulation study to estimate performance characteristic distributions efficiently. The effectiveness and limitations of the developed methodology for launch vehicle operations simulations are also discussed.
NASA Astrophysics Data System (ADS)
Xiao, Shou-Ne; Wang, Ming-Meng; Hu, Guang-Zhong; Yang, Guang-Wu
2017-09-01
In view of the problem that it's difficult to accurately grasp the influence range and transmission path of the vehicle top design requirements on the underlying design parameters. Applying directed-weighted complex network to product parameter model is an important method that can clarify the relationships between product parameters and establish the top-down design of a product. The relationships of the product parameters of each node are calculated via a simple path searching algorithm, and the main design parameters are extracted by analysis and comparison. A uniform definition of the index formula for out-in degree can be provided based on the analysis of out-in-degree width and depth and control strength of train carriage body parameters. Vehicle gauge, axle load, crosswind and other parameters with higher values of the out-degree index are the most important boundary conditions; the most considerable performance indices are the parameters that have higher values of the out-in-degree index including torsional stiffness, maximum testing speed, service life of the vehicle, and so on; the main design parameters contain train carriage body weight, train weight per extended metre, train height and other parameters with higher values of the in-degree index. The network not only provides theoretical guidance for exploring the relationship of design parameters, but also further enriches the application of forward design method to high-speed trains.
Rethinking design parameters in the search for optimal dynamic seating.
Pynt, Jennifer
2015-04-01
Dynamic seating design purports to lessen damage incurred during sedentary occupations by increasing sitter movement while modifying muscle activity. Dynamic sitting is currently defined by O'Sullivan et al. ( 2013a) as relating to 'the increased motion in sitting which is facilitated by the use of specific chairs or equipment' (p. 628). Yet the evidence is conflicting that dynamic seating creates variation in the sitter's lumbar posture or muscle activity with the overall consensus being that current dynamic seating design fails to fulfill its goals. Research is needed to determine if a new generation of chairs requiring active sitter involvement fulfills the goals of dynamic seating and aids cardio/metabolic health. This paper summarises the pursuit of knowledge regarding optimal seated spinal posture and seating design. Four new forms of dynamic seating encouraging active sitting are discussed. These are 1) The Core-flex with a split seatpan to facilitate a walking action while seated 2) the Duo balans requiring body action to create rocking 3) the Back App and 4) Locus pedestal stools both using the sitter's legs to drive movement. Unsubstantiated claims made by the designers of these new forms of dynamic seating are outlined. Avenues of research are suggested to validate designer claims and investigate whether these designs fulfill the goals of dynamic seating and assist cardio/metabolic health. Should these claims be efficacious then a new definition of dynamic sitting is suggested; 'Sitting in which the action is provided by the sitter, while the dynamic mechanism of the chair accommodates that action'.
Thermionic Reactor Design Studies
Schock, Alfred
1994-06-01
During the 1960's and early 70's the author performed extensive design studies, analyses, and tests aimed at thermionic reactor concepts that differed significantly from those pursued by other investigators. Those studies, like most others under Atomic Energy Commission (AEC and DOE) and the National Aeronautics and Space Administration (NASA) sponsorship, were terminated in the early 1970's. Some of this work was previously published, but much of it was never made available in the open literature. U.S. interest in thermionic reactors resumed in the early 80's, and was greatly intensified by reports about Soviet ground and flight tests in the late 80's. This recent interest resulted in renewed U.S. thermionic reactor development programs, primarily under Department of Defense (DOD) and Department of Energy (DOE) sponsorship. Since most current investigators have not had an opportunity to study all of the author's previous work, a review of the highlights of that work may be of value to them. The present paper describes some of the author's conceptual designs and their rationale, and the special analytical techniques developed to analyze their performance. The basic designs, first published in 1963, are based on single-cell converters, either double-ended diodes extending over the full height of the reactor core or single-ended diodes extending over half the core height. In that respect they are similar to the thermionic fuel elements employed in the Topaz-2 reactor subsequently developed in the Soviet Union, copies of which were recently imported by the U.S. As in the Topaz-2 case, electrically heated steady-state performance tests of the converters are possible before fueling. Where the author's concepts differed from the later Topaz-2 design was in the relative location of the emitter and the collector. Placing the fueled emitter on the outside of the cylindrical diodes permits much higher axial conductances to reduce ohmic losses in the electrodes of full
Designing a new computer mouse and evaluating some of its functional parameters.
Dehghan, Naser; Choobineh, Alireza; Razeghi, Mohsen; Hasanzadeh, Jafar; Irandoost, Moslem
2014-01-01
This study aimed to design a new mouse and evaluate some of its functional parameters. The prototype of an ergonomic mouse was made according to design principles. The study was conducted from 2011 to 2013 in the Department of Ergonomics in Shiraz University of Medical Science. Functional parameters including Movement Time (MT) and error rate of the new mouse were evaluated by 10 participants based on ISO 9241-9 standard. The application of design principles in the new mouse resulted in improving MT and error rate so that they could be comparable to those of a standard mouse. MT, in both the standard and the new mouse was 0.846 and 0.864 s, respectively. Error rate of the standard and the new mouse was reported as 13% and 19%, respectively. Statistical analysis showed no significant difference between the two mice from these perspectives. Apparently, the studied functional parameters of the new mouse were similar to those of the standard one. The new mouse could be an appropriate substitution for the standard mouse without losing its positive characteristics.
Influence of Various Material Design Parameters on Deformation Behaviors of TRIP Steels
Choi, Kyoo Sil; Soulami, Ayoub; Liu, Wenning N.; Sun, Xin; Khaleel, Mohammad A.
2010-11-02
In this paper, the microstructure-based finite element modeling method is used as a virtual design tool in investigating the respective influence of various material design parameters on the deformation behaviors of transformation induced plasticity (TRIP) steels. For this purpose, the separate effects of several different material design parameters, such as the volume fraction and stability of austenite phase and the strengths of the constituent phases, on the ultimate tensile strength (UTS) and ductility/formability of TRIP steels are quantitatively examined using different representative volume elements (RVEs) representing different TRIP steels. The computational results suggest that higher austenite stability is helpful in enhancing the ductility and formability of TRIP steels by delaying the martensitic transformation to a later stage, whereas increase of austenite volume fraction and/or ferrite strength alone is not beneficial to improve the performance of TRIP steels. The results in this study also indicate that various material design parameters must be adjusted concurrently to develop high performance TRIP steels. For example, the austenite strength should increase over the ferrite strength in order to induce the gradual/smooth martensitic transformation, and the strength disparity between the ferrite and the freshly-formed martensite phases should decrease in order to avoid higher stress/strain concentration along the phase boundaries. The modeling approach and results presented in this paper can be helpful in providing the deformation fundamentals for the development of high performance TRIP steels.
Data acquisition as a design parameter in the modern AEM
Zaluzec, N.J.
1993-04-01
The components of a modern analytical electron microscope (AEM) are not necessarily optimized. A pessimistic view is presented of an AEM system, particularly on the data acquisition end. The question of how to design the instrument to collect the data efficiently, is considered. Several points for doing this are outlined.
Gas flow parameters in laser cutting of wood- nozzle design
Kali Mukherjee; Tom Grendzwell; Parwaiz A.A. Khan; Charles McMillin
1990-01-01
The Automated Lumber Processing System (ALPS) is an ongoing team research effort to optimize the yield of parts in a furniture rough mill. The process is designed to couple aspects of computer vision, computer optimization of yield, and laser cutting. This research is focused on optimizing laser wood cutting. Laser machining of lumber has the advantage over...
Parameter Space Techniques for Robust Control System Design.
1980-07-01
been further investi- gated by Cruz [2] and Desoer and Wang [3]. In frequency design methods the concept to compensate the loop, such that high gains...of Feedback Systems, McGraw-Hill, New York, 1972. 3. C. A. Desoer and Y. T. Wang, "Foundations of Feedback Theory for Nonlinear Dynamical Systems
Percutaneous multiple electrode connector, design parameters and fabrication (biomedical)
NASA Technical Reports Server (NTRS)
Myers, L. A.
1977-01-01
A percutaneous multielectrode connector was designed which utilizes an ultrapure carbon collar to provide an infection free biocompatible passage through the skin. The device provides reliable electrical continuity, mates and demates readily with the implant, and is fabricated with processes and materials oriented to commercial production.
Development of Design and Economic Parameters for Passive Solar Systems.
1984-09-01
42.50 35.02 29.73 ANNUAL 00 511 883 1394 2062 2888 3878 Soso Pk PARAMETER A .727 .700 .674 .680 .617 . 5684 .561 OFF SOUJTH VTN/DO 81 .008 .008 .008...23.47 16.11 12.21 9.83 8.23 V72/O 73.55 34.02 19.92 13.68 10.37 5.35 6.9e VT3/DD 63.77 29.50 17.21 11.36 8.99 7.24 6.06 ANNULL 0D 251 639 1313 2255
Decoupling interrelated parameters for designing high performance thermoelectric materials.
Xiao, Chong; Li, Zhou; Li, Kun; Huang, Pengcheng; Xie, Yi
2014-04-15
The world's supply of fossil fuels is quickly being exhausted, and the impact of their overuse is contributing to both climate change and global political unrest. In order to help solve these escalating problems, scientists must find a way to either replace combustion engines or reduce their use. Thermoelectric materials have attracted widespread research interest because of their potential applications as clean and renewable energy sources. They are reliable, lightweight, robust, and environmentally friendly and can reversibly convert between heat and electricity. However, after decades of development, the energy conversion efficiency of thermoelectric devices has been hovering around 10%. This is far below the theoretical predictions, mainly due to the interdependence and coupling between electrical and thermal parameters, which are strongly interrelated through the electronic structure of the materials. Therefore, any strategy that balances or decouples these parameters, in addition to optimizing the materials' intrinsic electronic structure, should be critical to the development of thermoelectric technology. In this Account, we discuss our recently developed strategies to decouple thermoelectric parameters for the synergistic optimization of electrical and thermal transport. We first highlight the phase transition, which is accompanied by an abrupt change of electrical transport, such as with a metal-insulator and semiconductor-superionic conductor transition. This should be a universal and effective strategy to optimize the thermoelectric performance, which takes advantage of modulated electronic structure and critical scattering across phase transitions to decouple the power factor and thermal conductivity. We propose that solid-solution homojunction nanoplates with disordered lattices are promising thermoelectric materials to meet the "phonon glass electron crystal" approach. The formation of a solid solution, coupled with homojunctions, allows for
Automated Parameter Studies Using a Cartesian Method
NASA Technical Reports Server (NTRS)
Murman, Scott M.; Aftosimis, Michael J.; Nemec, Marian
2004-01-01
Computational Fluid Dynamics (CFD) is now routinely used to analyze isolated points in a design space by performing steady-state computations at fixed flight conditions (Mach number, angle of attack, sideslip), for a fixed geometric configuration of interest. This "point analysis" provides detailed information about the flowfield, which aides an engineer in understanding, or correcting, a design. A point analysis is typically performed using high fidelity methods at a handful of critical design points, e.g. a cruise or landing configuration, or a sample of points along a flight trajectory.
The optimization of design parameters for surge relief valve for pipeline systems
NASA Astrophysics Data System (ADS)
Kim, Hyunjun; Hur, Jisung; Kim, Sanghyun
2017-06-01
Surge is an abnormal pressure which induced by rapid changes of flow rate in pipeline systems. In order to protect pipeline system from the surge pressure, various hydraulic devices have been developed. Surge-relief valve(SRV) is one of the widely applied devices to control surge due to its feasibility in application, efficiency and cost-effectiveness. SRV is designed to automatically open under abnormal pressure and discharge the flow and makes pressure of the system drop to the allowable level. The performance of the SRV is influenced by hydraulics. According to previous studies, there are several affecting factors which determine performance of the PRV such as design parameters (e.g. size of the valve), system parameters (e.g. number of the valves and location of the valve), and operation parameters (e.g. set point and operation time). Therefore, the systematic consideration for factors affecting performance of SRV is required for the proper installation of SRV in the system. In this study, methodology for finding optimum parameters of the SRV is explored through the integration of Genetic Algorithm(GA) into surge analysis.
A Method for Designing CDO Conformed to Investment Parameters
NASA Astrophysics Data System (ADS)
Nakae, Tatsuya; Moritsu, Toshiyuki; Komoda, Norihisa
We propose a method for designing CDO (Collateralized Debt Obligation) that meets investor needs about attributes of CDO. It is demonstrated that adjusting attributes (that are credit capability and issue amount) of CDO to investors' preferences causes a capital loss risk that the agent takes. We formulate a CDO optimization problem by defining an objective function using the above risk and by setting constraints that arise from investor needs and a risk premium that is paid for the agent. Our prototype experiment, in which fictitious underlying obligations and investor needs are given, verifies that CDOs can be designed without opportunity loss and dead stock loss, and that the capital loss is not more than thousandth part of the amount of annual payment under guarantee for small and midium-sized enterprises by a general credit guarantee institution.
Controller Design for Linear Stochastic Systems with Uncertain Parameters.
1985-03-01
example may be designed on a numerical basis. Also, the equivalence of this solution to the minimax solution may be analyzed numerically . Finally, in...must be such that Equation (3a) has a unique solution that is sample-path continuous, c) w must be such that the cost function, (5), is well-defined...problem can be reformulated as an optimization problem with equality constraints. 3.3. Problem Redefinition and Solution The system equations , (3
Telemonitoring of vital parameters with newly designed biomedical clothing.
Weber, J-L; Blanc, D; Dittmar, A; Comet, B; Corroy, C; Noury, N; Baghai, R; Vaysse, S; Blinowska, A
2004-01-01
The paper describes the development of biomedical clothing for ambulatory telemonitoring of human vital parameters. VTAM (Vetement de Tele-Assistance Medicale) presents a T-shirt made from textile with woven wires and incorporating four smooth dry ECG electrodes, a breath rate sensor, a shock/fall detector and two temperature sensors. The garment is equipped for the signal pre-computing and transmission through a miniature GSM/GPRS module kept on a belt together with the power supply. Three VTAM prototypes have been tested on persons in a normal state of health using a medical protocol to assess the biomedical data that include an ECG reading, a pneumogram, temperature and fall detection in mobile situations.
Integrated technology wing design study
NASA Technical Reports Server (NTRS)
Hays, A. P.; Beck, W. E.; Morita, W. H.; Penrose, B. J.; Skarshaug, R. E.; Wainfan, B. S.
1984-01-01
The technology development costs and associated benefits in applying advanced technology associated with the design of a new wing for a new or derivative trijet with a capacity for 350 passengers and maximum range of 8519 km, entering service in 1990 were studied. The areas of technology are: (1) airfoil technology; (2) planform parameters; (3) high lift; (4) pitch active control system; (5) all electric systems; (6) E to 3rd power propulsion; (7) airframe/propulsion integration; (8) graphite/epoxy composites; (9) advanced aluminum alloys; (10) titanium alloys; and (11) silicon carbide/aluminum composites. These technologies were applied to the reference aircraft configuration. Payoffs were determined for block fuel reductions and net value of technology. These technologies are ranked for the ratio of net value of technology (NVT) to technology development costs.
NASA Technical Reports Server (NTRS)
Ribble, J. W.
1981-01-01
The mechanical design of a modular antenna concept was developed sufficiently to allow manufacture of a working demonstration model of a module, to predict mass properties, and to make performance estimates for antenna reflectors composed of these modules. The primary features of this concept are: (1) each module is an autonomous structural element which can be attached to adjacent modules through a three point connection; (2) the upper surface is a folding hexagonal truss plate mechanism which serves as the supporting structure for a reflective surface; and (3) the entire truss and surface can be folded into a cylindrical envelope in which all truss elements are essentially parallel. The kinematic studies and engineering demonstration model fully verified the deployment kinematics, stowing philosophy, and deployment sequencing for large antenna modules. It was established that such modules can be stowed in packages as small as 25 cm in diameter, using 1.27 cm diameter structural tubes. The development activity indicates that this deployable modular approach towards building large structures in space will support erection of 450 m apertures for operation up to 3 GHz with a single space shuttle flight.
NASA Technical Reports Server (NTRS)
Gerberich, Matthew W.; Oleson, Steven R.
2013-01-01
The Collaborative Modeling for Parametric Assessment of Space Systems (COMPASS) team at Glenn Research Center has performed integrated system analysis of conceptual spacecraft mission designs since 2006 using a multidisciplinary concurrent engineering process. The set of completed designs was archived in a database, to allow for the study of relationships between design parameters. Although COMPASS uses a parametric spacecraft costing model, this research investigated the possibility of using a top-down approach to rapidly estimate the overall vehicle costs. This paper presents the relationships between significant design variables, including breakdowns of dry mass, wet mass, and cost. It also develops a model for a broad estimate of these parameters through basic mission characteristics, including the target location distance, the payload mass, the duration, the delta-v requirement, and the type of mission, propulsion, and electrical power. Finally, this paper examines the accuracy of this model in regards to past COMPASS designs, with an assessment of outlying spacecraft, and compares the results to historical data of completed NASA missions.
Inherent uncertainties in meteorological parameters for wind turbine design
NASA Technical Reports Server (NTRS)
Doran, J. C.
1982-01-01
Major difficulties associated with meteorological measurments such as the inability to duplicate the experimental conditions from one day to the next are discussed. This lack of consistency is compounded by the stochastic nature of many of the meteorological variables of interest. Moreover, simple relationships derived in one location may be significantly altered by topographical or synoptic differences encountered at another. The effect of such factors is a degree of inherent uncertainty if an attempt is made to describe the atmosphere in terms of universal laws. Some of these uncertainties and their causes are examined, examples are presented and some implications for wind turbine design are suggested.
Parameter spaces and design optimization of thermoacoustic refrigerators
Wetzel, M.; Herman, C.
1996-12-31
In the last two decades thermoacoustic refrigerators were developed in research laboratories with the goal to understand the basic physics and thermodynamics of thermoacoustic heat pumping. These research efforts led to a good understanding of this new environmentally safe refrigeration technology that employs acoustic power to pump heat. Consequently the next step is to improve and optimize the performance of thermoacoustic refrigerators and seek commercial applications. For this purpose, the need for fast and simple engineering estimates arises. By implementing the simplified linear model of thermoacoustic refrigerators--the short stack boundary layer approximation--such design estimates were derived and presented in this paper in the form of a design algorithm. Calculations obtained with this algorithm predict values for the Coefficient Of Performance (COP) of the order of 5 to 6. These values cannot be achieved at this time because of loss mechanisms in key parts of the thermoacoustic refrigerator, which are not quite understood yet. Nevertheless, these values are encouraging and gaining a better understanding of these loss mechanisms will be a big step towards the commercial market for this new environmentally safe refrigeration technology.
NASA Astrophysics Data System (ADS)
Al-Halhouli, A. T.
2010-02-01
In this work, the concept of recently introduced electromagnetic pump has been presented. This pump has been proposed for pumping biomedical fluids carrying particles sensitive to shear stresses. Its working concept depends on controlling the rotation of two pistons placed in a circular channel in opposing polarity under the influence of a moving electromagnetic field. Analytical and numerical investigations on the effect of pump geometrical parameters on shear stresses at different boundary conditions are performed. The geometrical parameters include: channel aspect ratio (channel width to height) and channel radius ratio (inner to outer radius). Non-dimensional simple analytical shear stress expressions that are valid for a wide range of geometrical design parameters and variety of fluids are derived. CFD simulations have been used to verify the analytical expressions within the range of studied parameters. Obtained results showed that the analytical models predict the wall maximum shear stresses with an error less than 5% for w / h<=1.0 at high radius ratios and with an error less than10% for Ri / Ro >=0.3. These results help the designer in fabricating the micropump to be suitable for biomedical applications, where saving the particles carried in fluids from damage is of high importance.
Design parameters for carbon nanobottles to absorb and store methane.
Lee, Richard K F; Hill, James M
2011-08-01
We investigate the internal mechanics for methane storage in a nanobottle, which is assumed to comprise a metallofullerene located inside a carbon nanobottle, which is constructed from a half-fullerene as the base, and two nanotubes which are joined by a nanocone. The interaction potential energy for the metallofullerene is obtained from the 6-12 Lennard-Jones potential and the continuum approximation, which assumes that a discrete atomic structure can be replaced by an average atomic surface density. This potential energy shows that the metallofullerene has two minimum energy positions, which are located close to the neck of the bottle and at the base of the nanobottle, and therefore it may be used as a bottle-stopper to open or to close the nanobottle. At the neck of the bottle, the encapsulated metallofullerene closes the nanobottle, and by applying an external electrical force, the metallofullerene can overcome the energy barrier of the nanotube, and pass from the neck of the nanobottle to the base so that the nanobottle is open. For methane storage, the metallofullerene serves the dual purposes of opening and closing the nanobottle, as well as an attractor for the methane gas. The analytical formulation gives rise to a rapid computational capacity, and enables the direct determination of the optimal dimensions necessary to ensure the correct working function of the nanobottle, and specific ranges for the critical parameters are formulated.
ERIC Educational Resources Information Center
Environ Planning Design, 1970
1970-01-01
Floor plans and photographs illustrate a description of the Samuel C. Williams Library at Stevens Institute of Technology, Hoboken, N.J. The unusual interior design allows students to take full advantage of the library's resources. (JW)
Learning Effects in the Block Design Task: A Stimulus Parameter-Based Approach
ERIC Educational Resources Information Center
Miller, Joseph C.; Ruthig, Joelle C.; Bradley, April R.; Wise, Richard A.; Pedersen, Heather A.; Ellison, Jo M.
2009-01-01
Learning effects were assessed for the block design (BD) task, on the basis of variation in 2 stimulus parameters: perceptual cohesiveness (PC) and set size uncertainty (U). Thirty-one nonclinical undergraduate students (19 female) each completed 3 designs for each of 4 varied sets of the stimulus parameters (high-PC/high-U, high-PC/low-U,…
Optimization of design parameters of low-energy buildings
NASA Astrophysics Data System (ADS)
Vala, Jiří; Jarošová, Petra
2017-07-01
Evaluation of temperature development and related consumption of energy required for heating, air-conditioning, etc. in low-energy buildings requires the proper physical analysis, covering heat conduction, convection and radiation, including beam and diffusive components of solar radiation, on all building parts and interfaces. The system approach and the Fourier multiplicative decomposition together with the finite element technique offers the possibility of inexpensive and robust numerical and computational analysis of corresponding direct problems, as well as of the optimization ones with several design variables, using the Nelder-Mead simplex method. The practical example demonstrates the correlation between such numerical simulations and the time series of measurements of energy consumption on a small family house in Ostrov u Macochy (35 km northern from Brno).
The Design Parameters for the MICE Tracker Solenoid
Green, Michael A.; Chen, C.Y.; Juang, Tiki; Lau, Wing W.; Taylor,Clyde; Virostek, Steve P.; Wahrer, Robert; Wang, S.T.; Witte, Holger; Yang, Stephanie Q.
2006-08-20
The first superconducting magnets to be installed in the muon ionization cooling experiment (MICE) will be the tracker solenoids. The tracker solenoid module is a five coil superconducting solenoid with a 400 mm diameter warm bore that is used to provide a 4 T magnetic field for the experiment tracker module. Three of the coils are used to produce a uniform field (up to 4 T with better than 1 percent uniformity) in a region that is 300 mm in diameter and 1000 mm long. The other two coils are used to match the muon beam into the MICE cooling channel. Two 2.94-meter long superconducting tracker solenoid modules have been ordered for MICE. The tracker solenoid will be cooled using two-coolers that produce 1.5 W each at 4.2 K. The magnet system is described. The decisions that drive the magnet design will be discussed in this report.
Influence of design parameters on occurence of oil whirl
NASA Technical Reports Server (NTRS)
Ogrodnik, P. J.; Goodwin, M. J.; Penny, J. E. T.
1985-01-01
Oil whirl instability is a serious problem in oil lubricated journal bearings. The phenomenon is characterized by a subsynchronous vibration of the journal within the bush and is particularly apparent in turbogenerators, aeroengines and electric motors. A review is presented of previous papers on the subject of oil whirl, and a simple theory is described which was used to aid the design of an oil whirl test rig. Predictions of the onset of oil whirl made by the theory presented were found to agree with those of previous researchers. They showed that increasing the shaft flexibility, or the lubricant viscosity, and decreasing the bearing radial clearance tended to reduce the oil whirl onset speed thus making the system more unstable.
NASA Technical Reports Server (NTRS)
Hyland, D. C.
1983-01-01
A stochastic structural control model is described. In contrast to the customary deterministic model, the stochastic minimum data/maximum entropy model directly incorporates the least possible a priori parameter information. The approach is to adopt this model as the basic design model, thus incorporating the effects of parameter uncertainty at a fundamental level, and design mean-square optimal controls (that is, choose the control law to minimize the average of a quadratic performance index over the parameter ensemble).
Ju, Jonghyun; Han, Yun-ah; Kim, Seok-min
2013-03-07
The effects of structural design parameters on the performance of nano-replicated photonic crystal (PC) label-free biosensors were examined by the analysis of simulated reflection spectra of PC structures. The grating pitch, duty, scaled grating height and scaled TiO2 layer thickness were selected as the design factors to optimize the PC structure. The peak wavelength value (PWV), full width at half maximum of the peak, figure of merit for the bulk and surface sensitivities, and surface/bulk sensitivity ratio were also selected as the responses to optimize the PC label-free biosensor performance. A parametric study showed that the grating pitch was the dominant factor for PWV, and that it had low interaction effects with other scaled design factors. Therefore, we can isolate the effect of grating pitch using scaled design factors. For the design of PC-label free biosensor, one should consider that: (1) the PWV can be measured by the reflection peak measurement instruments, (2) the grating pitch and duty can be manufactured using conventional lithography systems, and (3) the optimum design is less sensitive to the grating height and TiO2 layer thickness variations in the fabrication process. In this paper, we suggested a design guide for highly sensitive PC biosensor in which one select the grating pitch and duty based on the limitations of the lithography and measurement system, and conduct a multi objective optimization of the grating height and TiO2 layer thickness for maximizing performance and minimizing the influence of parameter variation. Through multi-objective optimization of a PC structure with a fixed grating height of 550 nm and a duty of 50%, we obtained a surface FOM of 66.18 RIU-1 and an S/B ratio of 34.8%, with a grating height of 117 nm and TiO2 height of 210 nm.
Biological basis for space-variant sensor design I: parameters of monkey and human spatial vision
NASA Astrophysics Data System (ADS)
Rojer, Alan S.; Schwartz, Eric L.
1991-02-01
Biological sensor design has long provided inspiration for sensor design in machine vision. However relatively little attention has been paid to the actual design parameters provided by biological systems as opposed to the general nature of biological vision architectures. In the present paper we will provide a review of current knowledge of primate spatial vision design parameters and will present recent experimental and modeling work from our lab which demonstrates that a numerical conformal mapping which is a refinement of our previous complex logarithmic model provides the best current summary of this feature of the primate visual system. In this paper we will review recent work from our laboratory which has characterized some of the spatial architectures of the primate visual system. In particular we will review experimental and modeling studies which indicate that: . The global spatial architecture of primate visual cortex is well summarized by a numerical conformal mapping whose simplest analytic approximation is the complex logarithm function . The columnar sub-structure of primate visual cortex can be well summarized by a model based on a band-pass filtered white noise. We will also refer to ongoing work in our lab which demonstrates that: . The joint columnar/map structure of primate visual cortex can be modeled and summarized in terms of a new algorithm the ''''proto-column'''' algorithm. This work provides a reference-point for current engineering approaches to novel architectures for
ERIC Educational Resources Information Center
Kauppinen, Heta
1989-01-01
Explores the use of analogies in architectural design, the importance of Gestalt theory and aesthetic cannons in understanding and being sensitive to architecture. Emphasizes the variation between public and professional appreciation of architecture. Notes that an understanding of architectural process enables students to improve the aesthetic…
NASA Technical Reports Server (NTRS)
Howell, L. W.; Rose, M. Franklin (Technical Monitor)
2000-01-01
A simple power law model consisting of a single spectral index alpha (sub 1), is believed to be an adequate description of the galactic cosmic ray (GCR) proton flux at energies below 10(exp 13) eV, with a transition at knee energy E(sub k) to a steeper spectral index alpha(sub 2) greater than alpha(sub 1) above E(sub k). The maximum likelihood procedure is developed for estimating these three spectral parameters of the broken power law energy spectrum from simulated detector responses. These estimates and their surrounding statistical uncertainty are being used to derive the requirements in energy resolution, calorimeter size, and energy response of a proposed sampling calorimeter for the Advanced Cosmic ray Composition Experiment for the Space Station (ACCESS). This study thereby permits instrument developers to make important trade studies in design parameters as a function of the science objectives, which is particularly important for space-based detectors where physical parameters, such as dimension and weight, impose rigorous practical limits to the design envelope.
NASA Technical Reports Server (NTRS)
Howell, L. W.
2001-01-01
A simple power law model consisting of a single spectral index (alpha-1) is believed to be an adequate description of the galactic cosmic-ray (GCR) proton flux at energies below 10(exp 13) eV, with a transition at knee energy (E(sub k)) to a steeper spectral index alpha-2 > alpha-1 above E(sub k). The maximum likelihood procedure is developed for estimating these three spectral parameters of the broken power law energy spectrum from simulated detector responses. These estimates and their surrounding statistical uncertainty are being used to derive the requirements in energy resolution, calorimeter size, and energy response of a proposed sampling calorimeter for the Advanced Cosmic-ray Composition Experiment for the Space Station (ACCESS). This study thereby permits instrument developers to make important trade studies in design parameters as a function of the science objectives, which is particularly important for space-based detectors where physical parameters, such as dimension and weight, impose rigorous practical limits to the design envelope.
Hulland, Erin N; Blanton, Curtis J; Leidman, Eva Z; Bilukha, Oleg O
2016-01-01
Cluster surveys provide rapid but representative estimates of key nutrition indicators in humanitarian crises. For these surveys, an accurate estimate of the design effect is critical to calculate a sample size that achieves adequate precision with the minimum number of sampling units. This paper describes the variability in design effect for three key nutrition indicators measured in small-scale surveys and models the association of design effect with parameters hypothesized to explain this variability. 380 small-scale surveys from 28 countries conducted between 2006 and 2013 were analyzed. We calculated prevalence and design effect of wasting, underweight, and stunting for each survey as well as standard deviations of the underlying continuous Z-score distribution. Mean cluster size, survey location and year were recorded. To describe design effects, median and interquartile ranges were examined. Generalized linear regression models were run to identify potential predictors of design effect. Median design effect was under 2.00 for all three indicators; for wasting, the median was 1.35, the lowest among the indicators. Multivariable linear regression models suggest significant, positive associations of design effect and mean cluster size for all three indicators, and with prevalence of wasting and underweight, but not stunting. Standard deviation was positively associated with design effect for wasting but negatively associated for stunting. Survey region was significant in all three models. This study supports the current field survey guidance recommending the use of 1.5 as a benchmark for design effect of wasting, but suggests this value may not be large enough for surveys with a primary objective of measuring stunting or underweight. The strong relationship between design effect and region in the models underscores the continued need to consider country- and locality-specific estimates when designing surveys. These models also provide empirical evidence of a
Thermionic Reactor Design Studies
Schock, Alfred
1994-08-01
Paper presented at the 29th IECEC in Monterey, CA in August 1994. The present paper describes some of the author's conceptual designs and their rationale, and the special analytical techniques developed to analyze their (thermionic reactor) performance. The basic designs, first published in 1963, are based on single-cell converters, either double-ended diodes extending over the full height of the reactor core or single-ended diodes extending over half the core height. In that respect they are similar to the thermionic fuel elements employed in the Topaz-2 reactor subsequently developed in the Soviet Union, copies of which were recently imported by the U.S. As in the Topaz-2 case, electrically heated steady-state performance tests of the converters are possible before fueling.
Parameter study of a vehicle-scale hydrogen storage system.
Johnson, Terry Alan; Kanouff, Michael P.
2010-04-01
Sandia National Laboratories has developed a vehicle-scale prototype hydrogen storage system as part of a Work For Others project funded by General Motors. This Demonstration System was developed using the complex metal hydride sodium alanate. For the current work, we have continued our evaluation of the GM Demonstration System to provide learning to DOE's hydrogen storage programs, specifically the new Hydrogen Storage Engineering Center of Excellence. Baseline refueling data during testing for GM was taken over a narrow range of optimized parameter values. Further testing was conducted over a broader range. Parameters considered included hydrogen pressure and coolant flow rate. This data confirmed the choice of design pressure of the Demonstration System, but indicated that the system was over-designed for cooling. Baseline hydrogen delivery data was insufficient to map out delivery rate as a function of temperature and capacity for the full-scale system. A more rigorous matrix of tests was performed to better define delivery capabilities. These studies were compared with 1-D and 2-D coupled multi-physics modeling results. The relative merits of these models are discussed along with opportunities for improved efficiency or reduced mass and volume.
Hartt, W.H.
1999-07-01
The recently developed slope parameter approach to design of galvanic anode cathodic protection (cp) systems for marine structures constitutes an advancement in this technology compared to current practice, primarily because the former is first principles based and the latter is an empirical algorithm. In this paper, the slope parameter approach is reviewed; and related applications for which it can be utilized, including (1) design of new and retrofit cp systems, (2) evaluation of potential survey data, and (3) cp system design for complex geometries, are mentioned. The design current density is identified as the single remaining parameter for which values must be projected solely by experience or experimentation. In addition, the slope parameter approach is applied to the results of impressed current cp experiments, and it is shown how parameters for this can be interrelated with those of galvanic anode cp. Advantages of this capability are identified and discussed.
NASA Astrophysics Data System (ADS)
Ma, Tao; Zhang, Weigang; Zhang, Yang; Tang, Ting
2015-01-01
The current research of complex nonlinear system robust optimization mainly focuses on the features of design parameters, such as probability density functions, boundary conditions, etc. After parameters study, high-dimensional curve or robust control design is used to find an accurate robust solution. However, there may exist complex interaction between parameters and practical engineering system. With the increase of the number of parameters, it is getting hard to determine high-dimensional curves and robust control methods, thus it's difficult to get the robust design solutions. In this paper, a method of global sensitivity analysis based on divided variables in groups is proposed. By making relevant variables in one group and keeping each other independent among sets of variables, global sensitivity analysis is conducted in grouped variables and the importance of parameters is evaluated by calculating the contribution value of each parameter to the total variance of system response. By ranking the importance of input parameters, relatively important parameters are chosen to conduct robust design analysis of the system. By applying this method to the robust optimization design of a real complex nonlinear system-a vehicle occupant restraint system with multi-parameter, good solution is gained and the response variance of the objective function is reduced to 0.01, which indicates that the robustness of the occupant restraint system is improved in a great degree and the method is effective and valuable for the robust design of complex nonlinear system. This research proposes a new method which can be used to obtain solutions for complex nonlinear system robust design.
Probabilistic seismic hazard characterization and design parameters for the Pantex Plant
Bernreuter, D. L.; Foxall, W.; Savy, J. B.
1998-10-19
The Hazards Mitigation Center at Lawrence Livermore National Laboratory (LLNL) updated the seismic hazard and design parameters at the Pantex Plant. The probabilistic seismic hazard (PSH) estimates were first updated using the latest available data and knowledge from LLNL (1993, 1998), Frankel et al. (1996), and other relevant recent studies from several consulting companies. Special attention was given to account for the local seismicity and for the system of potentially active faults associated with the Amarillo-Wichita uplift. Aleatory (random) uncertainty was estimated from the available data and the epistemic (knowledge) uncertainty was taken from results of similar studies. Special attention was given to soil amplification factors for the site. Horizontal Peak Ground Acceleration (PGA) and 5% damped uniform hazard spectra were calculated for six return periods (100 yr., 500 yr., 1000 yr., 2000 yr., 10,000 yr., and 100,000 yr.). The design parameters were calculated following DOE standards (DOE-STD-1022 to 1024). Response spectra for design or evaluation of Performance Category 1 through 4 structures, systems, and components are presented.
The effect of urban design parameters on the local microclimate
Kakoniti, Androula; Georgiou, Gregoria; Neophytou, Marina; Marakkos, Konstantinos
2015-01-22
Two-dimensional steady-state simulations have been performed using the standard k-e turbulence model coupled with the heat transfer models available in the CFD software FLUENT 6.1, in order to examine the impact of radiation on the Urban Heat Island phenomenon. Specifically, the impact of radiation in three typical urban areas of Cyprus during the summer period is examined. The first geometry considered represents a typical suburban area and is termed as the reference geometry. The second geometry represents an area at the centre of a town with higher buildings and relatively narrower roads. The third geometry, on the other hand, describes a suburban area with wider roads and larger houses than the reference model. Computed values for air temperature in the urban street canyon have indicated that the increase in temperature associated with radiative heat transfer can be reduced by optimising the canyon geometry and, ultimately, help to mitigate the human thermal discomfort. The present study has also revealed that the selection of construction materials can be optimised to offer further reductions in the air temperature of the urban environment. It can be concluded that the combined effect of these remedies can lead to reductions in the energy consumption for building air-conditioning over the summer period.
Experimental study on HVAC sound parameters
NASA Astrophysics Data System (ADS)
Bujoreanu, C.; Benchea, M.
2016-08-01
HVAC system represent major source of buildings internal noise and therefore they are designed to provide a human acoustic comfort besides the thermal and air quality requirements. The paper experimentally investigates three types of commercial air handler units (AHU) with different ducts cross-section sizes and inlet-outlet configuration. The measurements are performed in an anechoic room. The measurements are carried out at different fan's speeds, ranging the power-charge from 30-100% while the duct air flow is slowly adjusted from full open to full closed, between 0-500 Pa. The sound pressure levels of the radiant units are rated using NR curves. Also, the supply and the outdoor ducts sound levels are compared in order to point the frequencies where the noise must be reduced. Third-octave band analysis of random noise of an air handling unit from a HVAC system is realized, using measurement procedures that agrees the requirements of the ISO 3744:2011 and ISO 5136:2010 standards. The comparatively results highlight the effects of the geometry, air flow pressure and power-charging dependencies upon the sound level. This is the start for a noise reduction strategy.
Design and parameter estimation of hybrid magnetic bearings for blood pump applications
NASA Astrophysics Data System (ADS)
Lim, Tau Meng; Zhang, Dongsheng; Yang, Juanjuan; Cheng, Shanbao; Low, Sze Hsien; Chua, Leok Poh; Wu, Xiaowei
2009-10-01
This paper discusses the design and parameter estimation of the dynamics characteristics of a high-speed hybrid magnetic bearings (HMBs) system for axial flow blood pump applications. The rotor/impeller of the pump is driven by a three-phase permanent magnet (PM) brushless and sensorless DC motor. It is levitated by two HMBs at both ends in five-degree-of-freedom with proportional-integral-derivative (PID) controllers; among which four radial directions are actively controlled and one axial direction is passively controlled. Test results show that the rotor can be stably supported to speeds of 14,000 rpm. The frequency domain parameter estimation technique with statistical analysis is adopted to validate the stiffness and damping coefficients of the HMBs system. A specially designed test rig facilitated the estimation of the bearing's coefficients in air—in both the radial and axial directions. The radial stiffness of the HMBs is compared to the Ansoft's Maxwell 2D/3D finite element magnetostatic results. Experimental estimation showed that the dynamics characteristics of the HMBs system are dominated by the frequency-dependent stiffness coefficients. The actuator gain was also successfully calibrated and may potentially extend the parameter estimation technique developed in the study of identification and monitoring of the pump's dynamics properties under normal operating conditions with fluid.
NASA Technical Reports Server (NTRS)
Deligiannis, F.; Perrone, D.; DiStefano, S.
1996-01-01
Simulation of spacecraft battery operation is implemented. Robust design experiment to obtain optimum battery operational parameters is performed. It is found that short term tests using robust design of experiments can provide guidelines for optimum battery operation. It is decided to use robust design approach to provide guidelines for battery operation on current spacecraft in orbit as batteries age (GRO, UARS, EUVE, TOPEX).
Deligiannis, F.; Perrone, D.; Distefano, S.
1996-02-01
Simulation of spacecraft battery operation is implemented. Robust design experiment to obtain optimum battery operational parameters is performed. It is found that short term tests using robust design of experiments can provide guidelines for optimum battery operation. It is decided to use robust design approach to provide guidelines for battery operation on current spacecraft in orbit as batteries age (GRO, UARS, EUVE, TOPEX).
NASA Technical Reports Server (NTRS)
Deligiannis, F.; Perrone, D.; DiStefano, S.
1996-01-01
Simulation of spacecraft battery operation is implemented. Robust design experiment to obtain optimum battery operational parameters is performed. It is found that short term tests using robust design of experiments can provide guidelines for optimum battery operation. It is decided to use robust design approach to provide guidelines for battery operation on current spacecraft in orbit as batteries age (GRO, UARS, EUVE, TOPEX).
Ye, Lin; Su, Steven W
2015-01-01
Optimum Experimental Design (OED) is an information gathering technique used to estimate parameters, which aims to minimize the variance of parameter estimation and prediction. In this paper, we further investigate an OED for MEMS accelerometer calibration of the 9-parameter auto-calibration model. Based on a linearized 9-parameter accelerometer model, we show the proposed OED is both G-optimal and rotatable, which are the desired properties for the calibration of wearable sensors for which only simple calibration devices are available. The experimental design is carried out with a newly developed wearable health monitoring device and desired experimental results have been achieved.
Effect of turning parameters on A16351 T6 by using Design of Experiments
NASA Astrophysics Data System (ADS)
Annigeri, Ulhas K.; Charan, M.; Vishnu Sai, M.; Ram Charan, T.; Rahul Sai, L.
2016-09-01
Aluminium is a well known lightest engineering metals. It is the most productive element on the earth crust. It can be extracted from bauxite, kaolinite or nepheline. It can be used in making aeroplane bodies, automobile parts etc. It is mostly used in multiple applications in order to reduce the weight of the component and it has fancy corrosion resistance. In the present study Al 6351 T6 is selected and a plain turning operation is performed on it with the help of design of experiments. The surface roughness of the samples are tested by varying the cutting parameters such as speed, feed, and depth of cut. A mathematical model is developed and the parameter which affects the surface roughness is determined.
Designing verbal autopsy studies
2010-01-01
Background Verbal autopsy analyses are widely used for estimating cause-specific mortality rates (CSMR) in the vast majority of the world without high-quality medical death registration. Verbal autopsies -- survey interviews with the caretakers of imminent decedents -- stand in for medical examinations or physical autopsies, which are infeasible or culturally prohibited. Methods and Findings We introduce methods, simulations, and interpretations that can improve the design of automated, data-derived estimates of CSMRs, building on a new approach by King and Lu (2008). Our results generate advice for choosing symptom questions and sample sizes that is easier to satisfy than existing practices. For example, most prior effort has been devoted to searching for symptoms with high sensitivity and specificity, which has rarely if ever succeeded with multiple causes of death. In contrast, our approach makes this search irrelevant because it can produce unbiased estimates even with symptoms that have very low sensitivity and specificity. In addition, the new method is optimized for survey questions caretakers can easily answer rather than questions physicians would ask themselves. We also offer an automated method of weeding out biased symptom questions and advice on how to choose the number of causes of death, symptom questions to ask, and observations to collect, among others. Conclusions With the advice offered here, researchers should be able to design verbal autopsy surveys and conduct analyses with greatly reduced statistical biases and research costs. PMID:20573233
Cordeiro, Cristiano M; Franco, Marcos A; Matos, Christiano J; Sircilli, Francisco; Serrão, Valdir A; Cruz, C H
2007-11-15
A microstructured optical fiber with a single design parameter is proposed and demonstrated. In such a structure three thin, long glass webs join in the fiber center, forming its core. By changing the web thickness it is possible to tune the zero-dispersion wavelength from approximately 0.7 to >2.0 microm while keeping a tiny core area and single-mode guidance. Supercontinuum generation is shown in a silica fiber with a web thickness of 850 nm. The small core area and the massive hole area also make the structure very attractive for the sensing and study of fluids.
Advanced turbocharger design study program
NASA Technical Reports Server (NTRS)
Culy, D. G.; Heldenbrand, R. W.; Richardson, N. R.
1984-01-01
The advanced Turbocharger Design Study consisted of: (1) the evaluation of three advanced engine designs to determine their turbocharging requirements, and of technologies applicable to advanced turbocharger designs; (2) trade-off studies to define a turbocharger conceptual design and select the engine with the most representative requirements for turbocharging; (3) the preparation of a turbocharger conceptual design for the Curtiss Wright RC2-32 engine selected in the trade-off studies; and (4) the assessment of market impact and the preparation of a technology demonstration plan for the advanced turbocharger.
Analytical considerations for study design
Barry R. Noon; William M. Block
1990-01-01
Studies of the foraging behaviors of birds have been largely descriptive and comparative. One might then expect studies with similar objectives to have similar study designs but that is not the case. Papers in this symposium that focused specifically on study design contain a diversity of biological perspectives. Similarly, there is no accord among statisticians on...
NASA Technical Reports Server (NTRS)
Stahara, S. S.; Elliott, J. P.; Spreiter, J. R.
1983-01-01
An investigation was conducted to continue the development of perturbation procedures and associated computational codes for rapidly determining approximations to nonlinear flow solutions, with the purpose of establishing a method for minimizing computational requirements associated with parametric design studies of transonic flows in turbomachines. The results reported here concern the extension of the previously developed successful method for single parameter perturbations to simultaneous multiple-parameter perturbations, and the preliminary application of the multiple-parameter procedure in combination with an optimization method to blade design/optimization problem. In order to provide as severe a test as possible of the method, attention is focused in particular on transonic flows which are highly supercritical. Flows past both isolated blades and compressor cascades, involving simultaneous changes in both flow and geometric parameters, are considered. Comparisons with the corresponding exact nonlinear solutions display remarkable accuracy and range of validity, in direct correspondence with previous results for single-parameter perturbations.
Parameter-Level Data Flow Modeling Oriented to Product Design Process
NASA Astrophysics Data System (ADS)
Li, Shen; Shao, Xiao Dong; Zhang, Zhi Hua; Ge, Xiao Bo
2015-12-01
In this paper, a method of data flow modeling for a product design process oriented to data parameter is proposed. The data parameters are defined, which are classified as the basic data parameters and complex data parameters. The mechanism of the mapping relationship between different forms of documents and some basic data parameters, and a data transmission based on parameters, are constructed. Aiming at the characteristics of the iterative design process, the parameters version mechanism including node modification and iteration information is proposed. The data parameters transmission relationships are represented by a parameters network model (PNM) based on a directed graph. Finally, through the table of data parameters mapping onto the workflow node and PNM, the data ports and data links in the data flow model are generated automatically by the program. Validation in the 15-meter-diameter S/Ka frequency band antenna design process of the “Reflector, Back frame and Center part design” data flow model shows that the method can effectively shorten the time of data flow modeling and improve the data transmission efficiency.
Mun, J S; Han, M Y
2012-01-01
The appropriate design and evaluation of a rainwater harvesting (RWH) system is necessary to improve system performance and the stability of the water supply. The main design parameters (DPs) of an RWH system are rainfall, catchment area, collection efficiency, tank volume and water demand. Its operational parameters (OPs) include rainwater use efficiency (RUE), water saving efficiency (WSE) and cycle number (CN). The sensitivity analysis of a rooftop RWH system's DPs to its OPs reveals that the ratio of tank volume to catchment area (V/A) for an RWH system in Seoul, South Korea is recommended between 0.03 and 0.08 in terms of rate of change in RUE. The appropriate design value of V/A is varied with D/A. The extra tank volume up to V/A of 0.15∼0.2 is also available, if necessary to secure more water. Accordingly, we should figure out suitable value or range of DPs based on the sensitivity analysis to optimize design of an RWH system or improve operation efficiency. The operational data employed in this study, which was carried out to validate the design and evaluation method of an RWH system, were obtained from the system in use at a dormitory complex at Seoul National University (SNU) in Korea. The results of these operational data are in good agreement with those used in the initial simulation. The proposed method and the results of this research will be useful in evaluating and comparing the performance of RWH systems. It is found that RUE can be increased by expanding the variety of rainwater uses, particularly in the high rainfall season. Copyright Â© 2011 Elsevier Ltd. All rights reserved.
Parameter Design and Optimal Control of an Open Core Flywheel Energy Storage System
NASA Technical Reports Server (NTRS)
Pang, D.; Anand, D. K.; Kirk, J. A.
1996-01-01
In low earth orbit (LEO) satellite applications spacecraft power is provided by photovoltaic cells and batteries. To overcome battery shortcomings the University of Maryland, working in cooperation with NASA/GSFC and NASA/LeRC, has developed a magnetically suspended flywheel for energy storage applications. The system is referred to as an Open Core Composite Flywheel (OCCF) energy storage system. Successful application of flywheel energy storage requires integration of several technologies, viz. bearings, rotor design, motor/generator, power conditioning, and system control. In this paper we present a parameter design method which has been developed for analyzing the linear SISO model of the magnetic bearing controller for the OCCF. The objective of this continued research is to principally analyze the magnetic bearing system for nonlinear effects in order to increase the region of stability, as determined by high speed and large air gap control. This is achieved by four tasks: (1) physical modeling, design, prototyping, and testing of an improved magnetically suspended flywheel energy storage system, (2) identification of problems that limit performance and their corresponding solutions, (3) development of a design methodology for magnetic bearings, and (4) design of an optimal controller for future high speed applications. Both nonlinear SISO and MIMO models of the magnetic system were built to study limit cycle oscillations and power amplifier saturation phenomenon observed in experiments. The nonlinear models include the inductance of EM coils, the power amplifier saturation, and the physical limitation of the flywheel movement as discussed earlier. The control program EASY5 is used to study the nonlinear SISO and MIMO models. Our results have shown that the characteristics and frequency responses of the magnetic bearing system obtained from modeling are comparable to those obtained experimentally. Although magnetic saturation is shown in the bearings, there
Noninvasive thrombolysis using microtripsy: a parameter study.
Zhang, Xi; Jin, Lifang; Vlaisavljevich, Eli; Owens, Gabe E; Gurm, Hitinder S; Cain, Charles A; Xu, Zhen
2015-12-01
Histotripsy fractionates soft tissue by well-controlled acoustic cavitation using microsecond-long, high-intensity ultrasound pulses. The feasibility of using histotripsy as a noninvasive, drug-free, and image-guided thrombolysis method has been shown previously. A new histotripsy approach, termed microtripsy, has recently been investigated for the thrombolysis application to improve treatment accuracy and avoid potential vessel damage. In this study, we investigated the effects of pulse repetition frequency (PRF) on microtripsy thrombolysis. Microtripsy thrombolysis treatments using different PRFs (5, 50, and 100 Hz) and doses (20, 50, and 100 pulses) were performed on blood clots in an in vitro vessel flow model. To quantitatively evaluate the microtripsy thrombolysis effect, the location of focal cavitation, the incident rate of pre-focal cavitation on the vessel wall, the size and location of the resulting flow channel, and the generated clot debris particles were measured. The results demonstrated that focal cavitation was always well confined in the vessel lumen without contacting the vessel wall for all PRFs. Pre-focal cavitation on the front vessel wall was never observed at 5Hz PRF, but occasionally observed at PRFs of 50 Hz (1.2%) and 100 Hz (5.4%). However, the observed pre-focal cavitation was weak and did not significantly affect the focal cavitation. Results further demonstrated that, although the extent of clot fractionation per pulse was the highest at 5 Hz PRF at the beginning of treatment (<20 pulses), 100 Hz PRF generated the largest flow channels with a much shorter treatment time. Finally, results showed fewer large debris particles were generated at a higher PRF. Overall, the results of this study suggest that a higher PRF (50 or 100 Hz) may be a better choice for microtripsy thrombolysis to use clinically due to the larger resulting flow channel, shorter treatment time, and smaller debris particles.
Review & Peer Review of “Parameters for Properly Designed and Operated Flares” Documents
This page contains two 2012 memoranda on the review of EPA's parameters for properly designed and operated flares. One details the process of peer review, and the other provides background information and specific charge questions to the panel.
Automated CFD Parameter Studies on Distributed Parallel Computers
NASA Technical Reports Server (NTRS)
Rogers, Stuart E.; Aftosmis, Michael; Pandya, Shishir; Tejnil, Edward; Ahmad, Jasim; Kwak, Dochan (Technical Monitor)
2002-01-01
The objective of the current work is to build a prototype software system which will automated the process of running CFD jobs on Information Power Grid (IPG) resources. This system should remove the need for user monitoring and intervention of every single CFD job. It should enable the use of many different computers to populate a massive run matrix in the shortest time possible. Such a software system has been developed, and is known as the AeroDB script system. The approach taken for the development of AeroDB was to build several discrete modules. These include a database, a job-launcher module, a run-manager module to monitor each individual job, and a web-based user portal for monitoring of the progress of the parameter study. The details of the design of AeroDB are presented in the following section. The following section provides the results of a parameter study which was performed using AeroDB for the analysis of a reusable launch vehicle (RLV). The paper concludes with a section on the lessons learned in this effort, and ideas for future work in this area.
Study of photodissociation parameters of carboxyhemoglobin
Kuz'min, V V; Salmin, V V; Provorov, A S; Salmina, A B
2008-07-31
The general properties of photodissociation of carboxyhemoglobin (HbCO) in buffer solutions of whole human blood are studied by the flash photolysis method on a setup with intersecting beams. It is shown that the efficiency of photoinduced dissociation of the HbCO complex virtually linearly depends on the photolytic irradiation intensity for the average power density not exceeding 45 mW cm{sup -2}. The general dissociation of the HbCO complex in native conditions occurs in a narrower range of values of the saturation degree than in model experiments with the hemoglobin solution. The dependence of the pulse photolysis efficiency of HbCO on the photolytic radiation wavelength in the range from 550 to 585 nm has a broad bell shape. The efficiency maximum corresponds to the electronic Q transition (porphyrin {pi}-{pi}* absorption) in HbCO at a wavelength of 570 nm. No dissociation of the complex was observed under given experimental conditions upon irradiation of solutions by photolytic radiation at wavelengths above 585 nm. (laser applications and other topics in quantum electronics)
Materials design parameters for infrared device applications based on III-V semiconductors.
Svensson, Stefan P; Sarney, Wendy L; Donetsky, Dmitry; Kipshidze, Gela; Lin, Youxi; Shterengas, Leon; Xu, Ye; Belenky, Gregory
2017-01-20
The collaborative development of infrared detector materials by the Army Research Laboratory and Stony Brook University has led to new fundamental understandings of materials, as well as new levels of control and flexibility in III-V semiconductor crystal growth by molecular beam epitaxy. Early work on mid-wave strained layer superlattice (SLS) cameras led to a subsequent focus on minority carrier lifetime studies, which resulted in the proposal of the Ga-free SLS on GaSb substrates. The later demonstration of virtual substrate technology allowed the lattice constant to become a design parameter and enabled growth of undistorted bulk InAsSb. When grown in that manner, InAsSb has a bandgap bowing parameter large enough to cover absorption wavelengths across the entire long-wavelength band (8-12 μm). Even longer wavelengths are achieved with a general Ga-free SLS approach, with a virtual substrate having a lattice constant significantly larger than that of GaSb and with InAsSb in both bi-layers in the period. Since these layers can also be made very thin, the general Ga-free SLS does not suffer from the relatively low optical absorption and poor hole transport, which is characteristic of the special Ga-free SLS on GaSb for long-wavelength designs. Finally, the general Ga-free InAsSb SLS provides a method to induce and control sustained atomic ordering, which is yet another new design parameter.
2008-01-01
Am. Ind. Hyg. Assoc. J. 1992, 53, pp 193-202. 4. Letowski, T.R.; Ricard, G.L.; Grieves, J.E. The Effect of the XM45 Gas Mask and Hood on Directional...Historical mask wear human performance research offers useful, albeit limited, insights on the relationships between design parameters and performance. The...purposes of the current task were to review and revise the existing human performance capabilities and mask design parameters databases and to derive new
Kwak, Dai Soon; Tao, Quang Bang; Todo, Mitsugu; Jeon, Insu
2012-05-01
Knee joint implants developed by western companies have been imported to Korea and used for Korean patients. However, many clinical problems occur in knee joints of Korean patients after total knee joint replacement owing to the geometric mismatch between the western implants and Korean knee joint structures. To solve these problems, a method to determine the representative dimension parameter values of Korean knee joints is introduced to aid in the design of knee joint implants appropriate for Korean patients. Measurements of the dimension parameters of 88 male Korean knee joint subjects were carried out. The distribution of the subjects versus each measured parameter value was investigated. The measured dimension parameter values of each parameter were grouped by suitable intervals called the "size group," and average values of the size groups were calculated. The knee joint subjects were grouped as the "patient group" based on "size group numbers" of each parameter. From the iterative calculations to decrease the errors between the average dimension parameter values of each "patient group" and the dimension parameter values of the subjects, the average dimension parameter values that give less than the error criterion were determined to be the representative dimension parameter values for designing knee joint implants for Korean patients.
Head parameter sensitivity study of the intrinsic field reversal time
NASA Astrophysics Data System (ADS)
George, Peter K.; Jury, Jason C.; Judy, Jack
1999-04-01
Studies to establish the key head sensitivity parameters affecting the intrinsic field reversal time are reported. The effect of supply voltage, eddy current damping, head moment, and turns are investigated using the nonlinear, eddy current damped, thin-film write head model proposed by Klaassen and Hirko [IEEE Trans. Magn. 32, 3524 (1996)]. The model is realized using PSPICE circuit simulation. Eddy current time constant dependencies derived by Wood, Williams, and Hong [IEEE Trans. Magn. 26, 2954 (1990)] are used to explore materials with magnetizations ranging from 4πMS=10-20 kG, resistivities of 25 and 125 μΩ-cm and heads with 10-15 turns. Confirmation of the above writer sensitivities has been investigated using a short yoke 37 turn, high moment, low eddy current CoTaZr inductive head. From the experimentally determined model parameters, rise time results are computed for an improved 10 turn writer design. The results are shown to approach or exceed the limiting dynamics of the spin system.
A Comparative Study of Distribution System Parameter Estimation Methods
Sun, Yannan; Williams, Tess L.; Gourisetti, Sri Nikhil Gup
2016-07-17
In this paper, we compare two parameter estimation methods for distribution systems: residual sensitivity analysis and state-vector augmentation with a Kalman filter. These two methods were originally proposed for transmission systems, and are still the most commonly used methods for parameter estimation. Distribution systems have much lower measurement redundancy than transmission systems. Therefore, estimating parameters is much more difficult. To increase the robustness of parameter estimation, the two methods are applied with combined measurement snapshots (measurement sets taken at different points in time), so that the redundancy for computing the parameter values is increased. The advantages and disadvantages of both methods are discussed. The results of this paper show that state-vector augmentation is a better approach for parameter estimation in distribution systems. Simulation studies are done on a modified version of IEEE 13-Node Test Feeder with varying levels of measurement noise and non-zero error in the other system model parameters.
NASA Astrophysics Data System (ADS)
Zhao, Tongke; Shu, Shi; Guo, Qiuju; Zhu, Yifang
2016-06-01
Emissions from electronic cigarettes (ECs) may contribute to both indoor and outdoor air pollution and the number of users is increasing rapidly. ECs operate based on the evaporation of e-liquid by a high-temperature heating coil. Both puff topography and design parameters can affect this evaporation process. In this study, both mainstream aerosols and heating coil temperature were measured concurrently to study the effects of design parameters and puff topography. The heating coil temperatures and mainstream aerosols varied over a wide range across different brands and within same brand. The peak heating coil temperature and the count median diameter (CMD) of EC aerosols increased with a longer puff duration and a lower puff flow rate. The particle number concentration was positively associated with the puff duration and puff flow rate. These results provide a better understanding of how EC emissions are affected by design parameters and puff topography and emphasize the urgent need to better regulate EC products.
Conceptual Design Parameters for HFIR LEU U-Mo Fuel Conversion Experimental Irradiations
Renfro, David G; Cook, David Howard; Chandler, David; Ilas, Germina; Jain, Prashant K
2013-03-01
The High Flux Isotope Reactor (HFIR) is a versatile research reactor that is operated at the Oak Ridge National Laboratory (ORNL). The HFIR core is loaded with high-enriched uranium (HEU) and operates at a power level of 85 MW. The primary scientific missions of the HFIR include cold and thermal neutron scattering, materials irradiation, and isotope production. An engineering design study of the conversion of the HFIR from HEU to low-enriched uranium (LEU) fuel is ongoing at the Oak Ridge National Laboratory. The LEU fuel considered is based on a uranium-molybdenum alloy that is 10 percent by weight molybdenum (U-10Mo) with a 235U enrichment of 19.75 wt %. The LEU core design discussed in this report is based on the design documented in ORNL/TM-2010/318. Much of the data reported in Sections 1 and 2 of this document was derived from or taken directly out of ORNL/TM-2010/318. The purpose of this report is to document the design parameters for and the anticipated normal operating conditions of the conceptual HFIR LEU fuel to aid in developing requirements for HFIR irradiation experiments.
Metocean design parameter estimation for fixed platform based on copula functions
NASA Astrophysics Data System (ADS)
Zhai, Jinjin; Yin, Qilin; Dong, Sheng
2017-08-01
Considering the dependent relationship among wave height, wind speed, and current velocity, we construct novel trivariate joint probability distributions via Archimedean copula functions. Total 30-year data of wave height, wind speed, and current velocity in the Bohai Sea are hindcast and sampled for case study. Four kinds of distributions, namely, Gumbel distribution, lognormal distribution, Weibull distribution, and Pearson Type III distribution, are candidate models for marginal distributions of wave height, wind speed, and current velocity. The Pearson Type III distribution is selected as the optimal model. Bivariate and trivariate probability distributions of these environmental conditions are established based on four bivariate and trivariate Archimedean copulas, namely, Clayton, Frank, Gumbel-Hougaard, and Ali-Mikhail-Haq copulas. These joint probability models can maximize marginal information and the dependence among the three variables. The design return values of these three variables can be obtained by three methods: univariate probability, conditional probability, and joint probability. The joint return periods of different load combinations are estimated by the proposed models. Platform responses (including base shear, overturning moment, and deck displacement) are further calculated. For the same return period, the design values of wave height, wind speed, and current velocity obtained by the conditional and joint probability models are much smaller than those by univariate probability. Considering the dependence among variables, the multivariate probability distributions provide close design parameters to actual sea state for ocean platform design.
NASA Astrophysics Data System (ADS)
Singh, R.; Verma, H. K.
2013-12-01
This paper presents a teaching-learning-based optimization (TLBO) algorithm to solve parameter identification problems in the designing of digital infinite impulse response (IIR) filter. TLBO based filter modelling is applied to calculate the parameters of unknown plant in simulations. Unlike other heuristic search algorithms, TLBO algorithm is an algorithm-specific parameter-less algorithm. In this paper big bang-big crunch (BB-BC) optimization and PSO algorithms are also applied to filter design for comparison. Unknown filter parameters are considered as a vector to be optimized by these algorithms. MATLAB programming is used for implementation of proposed algorithms. Experimental results show that the TLBO is more accurate to estimate the filter parameters than the BB-BC optimization algorithm and has faster convergence rate when compared to PSO algorithm. TLBO is used where accuracy is more essential than the convergence speed.
Pater, Cornel; Compagnone, Daniele; Luszick, Joachim; Verboom, Cees-Nico
2003-01-01
Background A large body of data derived from animal, epidemiological and clinical studies indicate that n-3 polyunsaturated fatty acids have a favourable effect on the prognosis of patients with cardiovascular disease in general, and on reducing sudden death in particular. Depressed heart rate variability (HRV), an indicator of impairment of the autonomic nervous system, has been shown to be a powerful predictor of subsequent mortality in patients surviving an acute myocardial infarction. A multitude of studies have demonstrated this strong association, suggesting that the imbalance in the sympathic/parasympathetic system may facilitate emergence of ventricular arrhythmias. Heart rate variability parameters will be assessed in the present study, with the primary objective of evaluating the possible superiority of Omacor (a highly refined, concentrated omega-3 fatty acid) versus placebo in improving HRV from baseline to endpoint in patients with recent uncomplicated myocardial infarction. Both groups will receive optimal conventional treatment. The study will also explore and quantify improvement in time domain HRV indices and will assess the safety of administering Omacor to optimally treated post-infarction patients (conventional treatment). Methods This multi-centre study will evaluate the effect of Omacor 1 g, o.d. on time-domain HRV parameters in comparison to placebo o.d. in patients with recent uncomplicated transmural myocardial infarction. Patients will be screened during the first few days after the acute event as appropriate for the patient's condition, and after obtaining informed consent. Based on inclusion/exclusion criteria, a first 24-hour Holter recording will be performed. Two to five days later, screened patients still eligible for the study will undergo a second 24-hour Holter recording. After the second Holter recording, all patients will be randomly allocated to treatment with Omacor 1 g, o.d. or placebo o.d. One hundred patients will be
NASA Technical Reports Server (NTRS)
Yarrow, Maurice; McCann, Karen M.; Biswas, Rupak; VanderWijngaart, Rob; Yan, Jerry C. (Technical Monitor)
2000-01-01
The creation of parameter study suites has recently become a more challenging problem as the parameter studies have now become multi-tiered and the computational environment has become a supercomputer grid. The parameter spaces are vast, the individual problem sizes are getting larger, and researchers are now seeking to combine several successive stages of parameterization and computation. Simultaneously, grid-based computing offers great resource opportunity but at the expense of great difficulty of use. We present an approach to this problem which stresses intuitive visual design tools for parameter study creation and complex process specification, and also offers programming-free access to grid-based supercomputer resources and process automation.
NASA Astrophysics Data System (ADS)
Zeiler, M.; Detraz, S.; Olantera, L.; Pezzullo, G.; Seif El Nasr-Storey, S.; Sigaud, C.; Soos, C.; Troska, J.; Vasey, F.
2016-01-01
Particle detectors for future experiments at the HL-LHC will require new optical data transmitters that can provide high data rates and be resistant against high levels of radiation. Furthermore, new design paths for future optical readout systems for HL-LHC could be opened if there was a possibility to integrate the optical components with their driving electronics and possibly also the silicon particle sensors themselves. All these functionalities could potentially be combined in the silicon photonics technology which currently receives a lot of attention for conventional optical link systems. Silicon photonic test chips were designed in order to assess the suitability of this technology for deployment in high-energy physics experiments. The chips contain custom-designed Mach-Zehnder modulators, pre-designed ``building-block'' modulators, photodiodes and various other passive test structures. The simulation and design flow of the custom designed Mach-Zehnder modulators and some first measurement results of the chips are presented.
Analysis of Design Parameters Effects on Vibration Characteristics of Fluidlastic Isolators
NASA Astrophysics Data System (ADS)
Deng, Jing-hui; Cheng, Qi-you
2017-07-01
The control of vibration in helicopters which consists of reducing vibration levels below the acceptable limit is one of the key problems. The fluidlastic isolators become more and more widely used because the fluids are non-toxic, non-corrosive, nonflammable, and compatible with most elastomers and adhesives. In the field of the fluidlastic isolators design, the selection of design parameters is very important to obtain efficient vibration-suppressed. Aiming at getting the effect of design parameters on the property of fluidlastic isolator, a dynamic equation is set up based on the theory of dynamics. And the dynamic analysis is carried out. The influences of design parameters on the property of fluidlastic isolator are calculated. Dynamic analysis results have shown that fluidlastic isolator can reduce the vibration effectively. Analysis results also showed that the design parameters such as the fluid density, viscosity coefficient, stiffness (K1 and K2) and loss coefficient have obvious influence on the performance of isolator. The efficient vibration-suppressed can be obtained by the design optimization of parameters.
Design parameters for toroidal and bobbin magnetics. [conversion from English to metric units
NASA Technical Reports Server (NTRS)
Mclyman, W. T.
1974-01-01
The adoption by NASA of the metric system for dimensioning to replace long-used English units imposes a requirement on the U.S. transformer designer to convert from the familiar units to the less familiar metric equivalents. Material is presented to assist in that transition in the field of transformer design and fabrication. The conversion data makes it possible for the designer to obtain a fast and close approximation of significant parameters such as size, weight, and temperature rise. Nomographs are included to provide a close approximation for breadboarding purposes. For greater convenience, derivations of some of the parameters are also presented.
ACSYNT inner loop flight control design study
NASA Technical Reports Server (NTRS)
Bortins, Richard; Sorensen, John A.
1993-01-01
The NASA Ames Research Center developed the Aircraft Synthesis (ACSYNT) computer program to synthesize conceptual future aircraft designs and to evaluate critical performance metrics early in the design process before significant resources are committed and cost decisions made. ACSYNT uses steady-state performance metrics, such as aircraft range, payload, and fuel consumption, and static performance metrics, such as the control authority required for the takeoff rotation and for landing with an engine out, to evaluate conceptual aircraft designs. It can also optimize designs with respect to selected criteria and constraints. Many modern aircraft have stability provided by the flight control system rather than by the airframe. This may allow the aircraft designer to increase combat agility, or decrease trim drag, for increased range and payload. This strategy requires concurrent design of the airframe and the flight control system, making trade-offs of performance and dynamics during the earliest stages of design. ACSYNT presently lacks means to implement flight control system designs but research is being done to add methods for predicting rotational degrees of freedom and control effector performance. A software module to compute and analyze the dynamics of the aircraft and to compute feedback gains and analyze closed loop dynamics is required. The data gained from these analyses can then be fed back to the aircraft design process so that the effects of the flight control system and the airframe on aircraft performance can be included as design metrics. This report presents results of a feasibility study and the initial design work to add an inner loop flight control system (ILFCS) design capability to the stability and control module in ACSYNT. The overall objective is to provide a capability for concurrent design of the aircraft and its flight control system, and enable concept designers to improve performance by exploiting the interrelationships between
Development of a parameter optimization technique for the design of automatic control systems
NASA Technical Reports Server (NTRS)
Whitaker, P. H.
1977-01-01
Parameter optimization techniques for the design of linear automatic control systems that are applicable to both continuous and digital systems are described. The model performance index is used as the optimization criterion because of the physical insight that can be attached to it. The design emphasis is to start with the simplest system configuration that experience indicates would be practical. Design parameters are specified, and a digital computer program is used to select that set of parameter values which minimizes the performance index. The resulting design is examined, and complexity, through the use of more complex information processing or more feedback paths, is added only if performance fails to meet operational specifications. System performance specifications are assumed to be such that the desired step function time response of the system can be inferred.
NASA Astrophysics Data System (ADS)
Baelmans, M.; Blommaert, M.; Dekeyser, W.; Van Oevelen, T.
2017-03-01
Plasma edge transport codes play a key role in the design of future divertor concepts. Their long simulation times in combination with a large number of control parameters turn the design into a challenging task. In aerodynamics and structural mechanics, adjoint-based optimization techniques have proven successful to tackle similar design challenges. This paper provides an overview of achievements and remaining challenges with these techniques for complex divertor design. It is shown how these developments pave the way for fast sensitivity analysis and improved design from different perspectives.
Correlation of mid-infrared quantum-cascade laser performance with laser design parameters
NASA Astrophysics Data System (ADS)
Leavitt, R. P.; Bradshaw, J. L.; Lascola, K. M.; Towner, F. J.; Pham, J. T.; Bruno, J. D.; Gmachl, C. F.; Liu, P. Q.
2012-06-01
Several different quantum-cascade (QC) laser designs spanning the wavelength range between ~3.8 and ~4.8 microns were grown, and devices were fabricated and tested. The active regions of these designs consist of strained layers of (In,Ga)As and (In,Al)As. For several of these designs, we varied design parameters including injector doping, sectioncoupling strength, and the number of QC laser periods. Lasers were tested near room temperature under both quasi-cw and low-duty-cycle conditions. Device performance is compared with theoretical expectations, and conclusions are reached on the relative merit of various design modifications.
Dependence of charge multiplication on different design parameters of LGAD devices
NASA Astrophysics Data System (ADS)
Jain, G.; Dalal, R.; Bhardwaj, A.; Ranjan, K.
2017-03-01
The Low Gain Avalanche Detectors (LGADs) have the unique characteristic to provide amplification to the particle signal by using a controlled local avalanche mechanism. These devices are being explored by the HEP community because, while it is known that in standard silicon detectors the signal-to-noise ratio falls drastically with fluence, in LGAD devices this can be made sufficiently high to potentially overcome this problem. However, the existing irradiation studies show that at high fluences, the LGAD internal gain disappears and is no more significant. In this work, we have studied the effect of various design parameters of the LGAD device on its gain characteristic, at different irradiation levels. With the acquired understanding, we have also tried to tune the LGAD gain so to be suited for operation in a high radiation environment.
Kleber, F X; Reindl, I; Wenzel, M; Rodewyk, P; Beil, S; Kosloswki, B; Doering, W; Sabin, G V; Hinzmann, S; Winter, U J
1993-12-01
Left ventricular damage by necrosis of myocardial tissue can lead to compromise of left ventricular function, to left ventricular volume increase and ultimately to development of heart failure. This sequence in the pathophysiology has been shown to be blunted by ACE inhibitors. Volume increase, however, can also be helpful in restoring stroke volume and ameliorate elevation of filling pressures. Furthermore, very early institution of ACE inhibition has failed to improve short-term mortality after myocardial infarction in one large trial. The aim of the ECCE trial therefore is, to investigate the early effects of the ACE inhibitor captopril on compromise of exercise capacity, thought to be a first measurable sign of developing heart failure. The ECCE trial is a randomized, seven-center investigation, studying the effects of ACE inhibition on oxygen uptake in a double blind, placebo controlled design in a group of 204 patients. Sample size was calculated on the basis of a pilot trial. The study design and first not unblinded data of 104 patients are presented. The population consists of predominantly male patients with mostly first myocardial infarction. They were admitted to hospital within five hours of onset of chest pain. End-diastolic volumes were normal, but ejection fraction was moderately compromised. ACE inhibition was started after the first day, but within 72 hours of onset of chest pain. After four and after twelve weeks, oxygen uptake was considerably below expected values and one third of the patients had severe compromise of exercise capacity.(ABSTRACT TRUNCATED AT 250 WORDS)
Study of parameters of a facility generating compressive plasma flows
NASA Astrophysics Data System (ADS)
Leyvi, A. Ya
2017-05-01
The prosperity of plasma technologies stimulates making of a facility generating compressive plasma flows at the South Ural State University. The facility is a compact-geometry magnetoplasma compressor with the following parameters: stored energy up to 15 kJ, voltage of a bank from 3 to 5 kV; nitrogen, air, and other gases can serve as its operating gas. The investigation of parameters of the facility showed the following parameters of compressive plasma flows: impulse duration of up to 120 μs, discharge current of 50-120 kA, speed of plasma flow of 15-30 km/s. By contrast to the available facilities, the parameters of the developed facility can be adjusted in a wide range of voltage from 2 kV to 10 kV, its design permits generating CPF in horizontal and vertical positions.
Effects of rock riprap design parameters on flood protection costs for uranium tailings impoundments
Ecker, R.M.
1984-07-01
The Pacific Northwest Laboratory (PNL) is studying the problem of long-term protection of earthen covers on decommissioned uranium tailings impoundments. The major erosive forces acting on these covers will be river flooding and overland flow from rainfall-runoff. For impoundments adjacent to rivers, overbank flooding presents the greater potential for significant erosion. To protect the earthen covers against flood erosion, rock riprap armoring will be placed over the cover surface. Because of the large size rock usually required for riprap, the quarrying, transport, and placement of the rock could be a significant part of the decommissioning cost. This report examines the sensitivity of riprap protection costs to certain design parameters at tailings impoundments. The parameters include flood discharge, riprap materials, impoundment side slopes, and an added safety factor. Two decommissioned tailings impoundments are used as case studies for the evaluation. These are the Grand Junction, Colorado, impoundment located adjacent to the Colorado River and the Slickrock, Colorado, impoundment located adjacent to the Dolores River. The evaluation considers only the cost of riprap protection against flood erosion. The study results show that embankment side slope and rock specific gravity can have optimum values or ranges at a specific site. For both case study sites the optimum side slope is about 5H:1V. Of the rock sources considered at Grand Junction, the optimum specific gravity would be about 2.50; however, an optimum rock specific gravity for the Slickrock site could not be determined. Other results indicate that the arbitrary safety factor usually added in riprap design can lead to large increases in protection costs. 22 references, 19 figures, 15 tables.
Effect of inflow cannula tip design on potential parameters of blood compatibility and thrombosis.
Wong, Kai Chun; Büsen, Martin; Benzinger, Carrie; Gäng, René; Bezema, Mirko; Greatrex, Nicholas; Schmitz-Rode, Thomas; Steinseifer, Ulrich
2014-09-01
During ventricular assist device support, a cannula acts as a bridge between the native cardiovascular system and a foreign mechanical device. Cannula tip design strongly affects the function of the cannula and its potential for blood trauma. In this study, the flow fields of five different tip geometries within the ventricle were evaluated using stereo particle image velocimetry. Inflow cannulae with conventional tip geometries (blunt, blunt with four side ports, beveled with three side ports, and cage) and a custom-designed crown tip were interposed between a mixed-flow rotary blood pump and a compressible, translucent silicone left ventricle. The contractile function of the failing ventricle and hemodynamics were reproduced in a mock circulation loop. The rotary blood pump was interfaced with the ventricle and aorta and used to fully support the failing ventricle. Among these five tip geometries, high-shear volume ( γ ˙ ≥ 2778 / s , potential parameter of platelet activation) was found to be the greatest in the blunt tip. The cage tip was observed to have the highest low-shear volume and recirculation volume ( γ ˙ ≤ 100 / s and Vz > 0, respectively; potential parameters of thrombus formation). The crown tip, together with conventional tip geometries with side ports (blunt with four side ports and beveled with three side ports) showed no significant difference in either high-shear volume or low-shear volume. However, recirculation volume was reduced significantly in the crown tip. Despite limited generalizability to clinical situations, these transient-state measurements supported the potential mitigation of complications by changing the design of conventional cannula tip geometries.
Particle Shape: A New Design Parameter for Micro- and Nanoscale Drug Delivery Carriers
Champion, Julie A.; Katare, Yogesh K.; Mitragotri, Samir
2014-01-01
Encapsulation of therapeutic agents in polymer particles has been successfully used in the development of new drug carriers. A number of design parameters that govern the functional behavior of carriers, including the choice of polymer, particle size and surface chemistry, have been tuned to optimize their performance in vivo. However, particle shape, which may also have a strong impact on carrier performance, has not been investigated. This is perhaps due to the limited availability of techniques to produce non-spherical polymer particles. In recent years, a number of reports have emerged to directly address this bottleneck and initial studies have indeed confirmed that particle shape can significantly impact the performance of polymer drug carriers. This article provides a review of this field with respect to methods of particle preparation and the role of particle shape in drug delivery. PMID:17544538
First-order method of zoom lens design by means of generalized parameters.
Khorokhorov, Alexei M; Piskunov, Dmitry E; Shirankov, Alexander F
2016-08-01
A method of paraxial zoom lens design is proposed that makes it possible to determine the optical powers and component movements of a zoom lens with the required zoom ratio. The method is based on the theory of generalized parameters, which can be used to analyze a zoom system by varying only one parameter. All possible zoom lenses with two movable components are considered for an object at infinity.
Instructional Designers at Work: A Study of How Designers Design
ERIC Educational Resources Information Center
Dicks, Dennis; Ives, Cindy
2008-01-01
Instructional design (ID) in its short life has been dominated by behaviourist approaches despite critique focusing on issues of practice as well as theory. Nonetheless, little research has addressed two fundamental questions: "What constitutes good instructional design?" and "How do instructional designers create good design?"…
Optimal input design for aircraft parameter estimation using dynamic programming principles
NASA Technical Reports Server (NTRS)
Klein, Vladislav; Morelli, Eugene A.
1990-01-01
A new technique was developed for designing optimal flight test inputs for aircraft parameter estimation experiments. The principles of dynamic programming were used for the design in the time domain. This approach made it possible to include realistic practical constraints on the input and output variables. A description of the new approach is presented, followed by an example for a multiple input linear model describing the lateral dynamics of a fighter aircraft. The optimal input designs produced by the new technique demonstrated improved quality and expanded capability relative to the conventional multiple input design method.
Optimal input design for aircraft parameter estimation using dynamic programming principles
NASA Technical Reports Server (NTRS)
Klein, Vladislav; Morelli, Eugene A.
1990-01-01
A new technique was developed for designing optimal flight test inputs for aircraft parameter estimation experiments. The principles of dynamic programming were used for the design in the time domain. This approach made it possible to include realistic practical constraints on the input and output variables. A description of the new approach is presented, followed by an example for a multiple input linear model describing the lateral dynamics of a fighter aircraft. The optimal input designs produced by the new technique demonstrated improved quality and expanded capability relative to the conventional multiple input design method.
Optimal Input Design for Aircraft Parameter Estimation using Dynamic Programming Principles
NASA Technical Reports Server (NTRS)
Morelli, Eugene A.; Klein, Vladislav
1990-01-01
A new technique was developed for designing optimal flight test inputs for aircraft parameter estimation experiments. The principles of dynamic programming were used for the design in the time domain. This approach made it possible to include realistic practical constraints on the input and output variables. A description of the new approach is presented, followed by an example for a multiple input linear model describing the lateral dynamics of a fighter aircraft. The optimal input designs produced by the new technique demonstrated improved quality and expanded capability relative to the conventional multiple input design method.
Knopman, D.S.; Voss, C.I.
1989-01-01
Optimal design of a sampling network is a sequential process in which the next phase of sampling is designed on the basis of all available physical knowledge of the system. Three objectives are considered: model discrimination, parameter estimation, and cost minimization. For the first two objectives, physically based measures of the value of information obtained from a set of observations are specified. In model discrimination, value of information of an observation point is measured in terms of the difference in solute concentration predicted by hypothesized models of transport. Points of greatest difference in predictions can contribute the most information to the discriminatory power of a sampling design. Sensitivity of solute concentration to a change in a parameter contributes information on the relative variance of a parameter estimate. Inclusion of points in a sampling design with high sensitivities to parameters tends to reduce variance in parameter estimates. Cost minimization accounts for both the capital cost of well installation and the operating costs of collection and analysis of field samples. -from Authors
Knopman, Debra S.; Voss, Clifford I.
1987-01-01
The spatial and temporal variability of sensitivities has a significant impact on parameter estimation and sampling design for studies of solute transport in porous media. Physical insight into the behavior of sensitivities is offered through an analysis of analytically derived sensitivities for the one-dimensional form of the advection-dispersion equation. When parameters are estimated in regression models of one-dimensional transport, the spatial and temporal variability in sensitivities influences variance and covariance of parameter estimates. Several principles account for the observed influence of sensitivities on parameter uncertainty. (1) Information about a physical parameter may be most accurately gained at points in space and time. (2) As the distance of observation points from the upstream boundary increases, maximum sensitivity to velocity during passage of the solute front increases. (3) The frequency of sampling must be 'in phase' with the S shape of the dispersion sensitivity curve to yield the most information on dispersion. (4) The sensitivity to the dispersion coefficient is usually at least an order of magnitude less than the sensitivity to velocity. (5) The assumed probability distribution of random error in observations of solute concentration determines the form of the sensitivities. (6) If variance in random error in observations is large, trends in sensitivities of observation points may be obscured by noise. (7) Designs that minimize the variance of one parameter may not necessarily minimize the variance of other parameters.
Studies in remotely sensed geophysical parameter retrieval and analysis
NASA Technical Reports Server (NTRS)
Perkey, Donald J.
1993-01-01
This report describes Universities Space Research Association (USRA) activities in support of the Geophysical Parameter Retrieval and Analysis studies. Specifically it addresses personnel assigned to the effort, travel, consultant participants, technical progress, and contract spending.
Piloted studies of Enhanced or Synthetic Vision display parameters
NASA Technical Reports Server (NTRS)
Harris, Randall L., Sr.; Parrish, Russell V.
1992-01-01
This paper summarizes the results of several studies conducted at Langley Research Center over the past few years. The purposes of these studies were to investigate parameters of pictorial displays and imaging sensors that affect pilot approach and landing performance. Pictorial displays have demonstrated exceptional tracking performance and improved the pilots' spatial awareness. Stereopsis cueing improved pilot flight performance and reduced pilot stress. Sensor image parameters such as increased field-of-view. faster image update rate, and aiding symbology improved flare initiation. Finer image resolution and magnification improved attitude control performance parameters.
Effect of buoyancy and power design parameters on hybrid airship performance
NASA Technical Reports Server (NTRS)
Talbot, P. D.; Gelhausen, P. A.
1983-01-01
The effects of several design parameters on the performance of hybrid airships having rotors and propellers were examined with a simple mathematical model. The parameters included buoyancy ratio, Froude number, ratio of rotor power to total power, and rotor shaft tilt. Performance variations resulting from changes in these parameters were calculated, and are presented and discussed. Performance quantities included best climb rate, equivalent vehicle L/D, and maximum speed. Performance at all speeds between hover and maximum speed was found to be sensitive to power distribution between rotors and propellers, and to rotor shaft tilt.
The effect of additional design parameters on the LQR based design of a control/structural system
NASA Technical Reports Server (NTRS)
Bainum, Peter M.; Xu, Jianke
1990-01-01
A multiobjective cost function that includes a form of the standard LQR regulator cost and its partial variation with respect to the additional design parameters is presented in connection with the design of an orbiting control/structural system. Simple models of uniform solid and tubular beams are demonstrated with two typical additional payload masses, i.e., symmetrically distributed and asymmetrically distributed, with respect to the center of the beam. By regarding the transient response of pitch angle and free-free beam deformations in the orbital plane, the optimal outer diameter of the beam and all feedback control can be determined by numerical analysis with this multicriterial approach. It is concluded that the multicriteria design approach should give better results from both the structural designer's and the control designer's standpoints.
Optimisation study of a vehicle bumper subsystem with fuzzy parameters
NASA Astrophysics Data System (ADS)
Farkas, L.; Moens, D.; Donders, S.; Vandepitte, D.
2012-10-01
This paper deals with the design and optimisation for crashworthiness of a vehicle bumper subsystem, which is a key scenario for vehicle component design. The automotive manufacturers and suppliers have to find optimal design solutions for such subsystems that comply with the conflicting requirements of the regulatory bodies regarding functional performance (safety and repairability) and regarding the environmental impact (mass). For the bumper design challenge, an integrated methodology for multi-attribute design engineering of mechanical structures is set up. The integrated process captures the various tasks that are usually performed manually, this way facilitating the automated design iterations for optimisation. Subsequently, an optimisation process is applied that takes the effect of parametric uncertainties into account, such that the system level of failure possibility is acceptable. This optimisation process is referred to as possibility-based design optimisation and integrates the fuzzy FE analysis applied for the uncertainty treatment in crash simulations. This process is the counterpart of the reliability-based design optimisation used in a probabilistic context with statistically defined parameters (variabilities).
Calculation of Design Parameters for an Equilibrium LEU Core in the NBSR
Hanson, A.L.; Diamond, D.
2011-09-30
A plan is being developed for the conversion of the NIST research reactor (NBSR) from high-enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel. Previously, the design of the LEU fuel had been determined in order to provide the users of the NBSR with the same cycle length as exists for the current HEU fueled reactor. The fuel composition at different points within an equilibrium fuel cycle had also been determined. In the present study, neutronics parameters have been calculated for these times in the fuel cycle for both the existing HEU and the proposed LEU equilibrium cores. The results showed differences between the HEU and LEU cores that would not lead to any significant changes in the safety analysis for the converted core. In general the changes were reasonable except that the figure-of-merit for neutrons that can be used by experimentalists shows there will be a 10% reduction in performance. The calculations included kinetics parameters, reactivity coefficients, reactivity worths of control elements and abnormal configurations, and power distributions.
A parameter identifiability study of two chalk tracer tests
NASA Astrophysics Data System (ADS)
Mathias, S. A.; Butler, A. P.; Atkinson, T. C.; Kachi, S.; Ward, R. S.
2006-08-01
As with most fractured rock formations, Chalk is highly heterogeneous. Therefore, meaningful estimates of model parameters must be obtained at a scale comparable with the process of concern. These are frequently obtained by calibrating an appropriate model to observed concentration-time data from radially convergent tracer tests (RCTT). Arguably, an appropriate model should consider radially convergent dispersion (RCD) and Fickian matrix diffusion. Such a model requires the estimation of at least four parameters. A question arises as to whether or not this level of model complexity is supported by the information contained within the calibration data. Generally modellers have not answered this question due to the calibration techniques employed. A dual-porosity model with RCD was calibrated to two tracer test datasets from different UK Chalk aquifers. A multivariate sensitivity analysis, which assumed only a priori upper and lower bounds for each model parameter, was undertaken. Rather than looking at measures of uncertainty, the shape of the multivariate objective function surface was used to determine whether a parameter was identifiable. Non-identifiable parameters were then removed and the procedure was repeated until all remaining parameters were identifiable. It was found that the single fracture model (SFM) (which ignores mechanical dispersion) obtained the best mass recovery, excellent model performance and best parameter identifiability in both the tests studied. However, there was no objective evidence suggesting that mechanical dispersion was negligible. Moreover, the SFM (with just two parameters) was found to be good at approximating the Single Fracture Dispersion Model SFDM (with three parameters) when different, and potentially erroneous parameters, were used. Overall, this study emphasises the importance of adequate temporal sampling of breakthrough curve data prior to peak concentrations, to ensure adequate characterisation of mechanical dispersion
Landsat image registration - A study of system parameters
NASA Technical Reports Server (NTRS)
Wacker, A. G.; Juday, R. D.; Wolfe, R. H., Jr.
1984-01-01
Some applications of Landsat data, particularily agricultural and forestry applications, require the ability to geometrically superimpose or register data acquired at different times and possibly by different satellites. An experimental investigation relating to a registration processor used by the Johnson Space Center for this purpose is the subject of this paper. Correlation of small subareas of images is at the heart of this registration processor and the manner in which various system parameters affect the correlation process is the prime area of investigation. Parameters investigated include preprocessing methods, methods for detecting sucessful correlations, fitting a surface to the correlation patch, fraction of pixels designated as edge pixels in edge detection adn local versus global generation of edge images. A suboptimum search procedure is used to find a good parameter set for this registration processor.
Visual Design Principles: An Empirical Study of Design Lore
ERIC Educational Resources Information Center
Kimball, Miles A.
2013-01-01
Many books, designers, and design educators talk about visual design principles such as balance, contrast, and alignment, but with little consistency. This study uses empirical methods to explore the lore surrounding design principles. The study took the form of two stages: a quantitative literature review to determine what design principles are…
Visual Design Principles: An Empirical Study of Design Lore
ERIC Educational Resources Information Center
Kimball, Miles A.
2013-01-01
Many books, designers, and design educators talk about visual design principles such as balance, contrast, and alignment, but with little consistency. This study uses empirical methods to explore the lore surrounding design principles. The study took the form of two stages: a quantitative literature review to determine what design principles are…
Parametric Design Studies on a Direct Liquid Feed Fuel Cell
NASA Technical Reports Server (NTRS)
Frank, H. A.; Narayanan, S. R.; Nakamura, B.; Surampudi, S.; Halpert, G.
1995-01-01
Parametric design studies were carried out on a direct methanol liquid feed fuel cell employing 1 M MeOH fuel, air and oxygen as oxidant in a 2 inch x 2 inch cell employing polymeric electrolyte membranes. Measurements include voltage-current output parameters, methanol crossover rate, and impedance as a function of several design and operational variables. Design variables are described.
Influence of some design parameters on the thermal performance of domestic refrigerator appliances
NASA Astrophysics Data System (ADS)
Rebora, Alessandro; Senarega, Maurizio; Tagliafico, Luca A.
2006-07-01
This paper presents a thermal study on chest-freezers, the small refrigerators used in domestic and supermarket applications. A thermal and energy model of a particular kind of these refrigerators, the “hot-wall” (or “skin condenser”) refrigerator, is developed and used to perform sensitivity and design optimisation analysis for given working temperatures and useful volume of the refrigerated cell. A finite-element heat transfer model of the refrigerator box is coupled to the complete thermodynamic model of the refrigerating plant, including real working conditions (compressor efficiency, friction pressure losses and so on). A sensitivity study of the main design parameters affecting the global refrigerator performance has been developed (for fixed working temperatures) with reference to the thickness of the metallic plates, to the evaporator and condenser tube diameters and to the evaporator tube pitch (with fixed evaporator-to-condenser tube pitch ratio). The results obtained show that the proposed sensitivity analysis can yield quite reliable results (in comparison with much more complex, albeit more accurate mathematical optimisation algorithms) using small computational resources. The great importance of 2-D heat conduction in the metallic plates is shown, evidencing how the plate thickness and the evaporator and condenser tube diameters affect the global performance of the system according to the well-known “fin efficiency” effect. The influence of the evaporator and condenser tube diameters on the friction pressure losses is also outlined. Some practical suggestions are made in conclusion, regarding the criteria which should be adopted in the thermal design of a hot-wall refrigerator.
Rijneveld, Wilhelmina J; Wolff, Rachel; Völker-Dieben, Hennie J M; Pels, Elisabeth
2011-12-01
To validate tissue quality parameters for donor corneas designated for emergency grafting for corneal graft survival. In a longitudinal cohort follow-up study, 131 emergency penetrating grafts were studied. Grafts were performed with a pool of organ-cultured donor corneas designated for emergency grafting and prepared for immediate use with all safety tests performed. Assignation criteria were: corneas with a small superficial stromal opacity but meeting all selection criteria for PKP tissue and corneas without stromal opacity, but an endothelial cell density from 1800 to 2300 cells/mm(2) or mild polymegathism or pleomorphism. Cox multivariate regression analysis, Kaplan-Meier survival and log rank test were applied. Of the 131 keratoplasties, 115 could be followed. One eye was lost during surgery because of an expulsive bleeding. In 15 cases, a conjunctival transplantation finished off the penetrating graft. Corneal graft survival was not significantly related to the presence of PKP quality of the donor endothelium, neither with a cloudy graft nor with endothelial decompensation as the cause of failure. Main risk factors for a failed graft were vascularization of the host cornea (p=0.0001), the presence of a systemic auto immune disease in the recipient (p=0.003) and the disease leading to the (imminent) perforation and emergency graft (p=0.021). A selected pool of donor corneas designated for emergency grafting that does not interfere with the scheduled procedures allows more efficient and safe use of donor tissue in case of a(n) (imminent) perforation. Corneal graft survival rates justify the criteria for selection. © 2009 The Authors. Journal compilation © 2009 Acta Ophthalmol.
The Limitations of Model-Based Experimental Design and Parameter Estimation in Sloppy Systems.
White, Andrew; Tolman, Malachi; Thames, Howard D; Withers, Hubert Rodney; Mason, Kathy A; Transtrum, Mark K
2016-12-01
We explore the relationship among experimental design, parameter estimation, and systematic error in sloppy models. We show that the approximate nature of mathematical models poses challenges for experimental design in sloppy models. In many models of complex biological processes it is unknown what are the relevant physical mechanisms that must be included to explain system behaviors. As a consequence, models are often overly complex, with many practically unidentifiable parameters. Furthermore, which mechanisms are relevant/irrelevant vary among experiments. By selecting complementary experiments, experimental design may inadvertently make details that were ommitted from the model become relevant. When this occurs, the model will have a large systematic error and fail to give a good fit to the data. We use a simple hyper-model of model error to quantify a model's discrepancy and apply it to two models of complex biological processes (EGFR signaling and DNA repair) with optimally selected experiments. We find that although parameters may be accurately estimated, the discrepancy in the model renders it less predictive than it was in the sloppy regime where systematic error is small. We introduce the concept of a sloppy system-a sequence of models of increasing complexity that become sloppy in the limit of microscopic accuracy. We explore the limits of accurate parameter estimation in sloppy systems and argue that identifying underlying mechanisms controlling system behavior is better approached by considering a hierarchy of models of varying detail rather than focusing on parameter estimation in a single model.
The Limitations of Model-Based Experimental Design and Parameter Estimation in Sloppy Systems
Tolman, Malachi; Thames, Howard D.; Mason, Kathy A.
2016-01-01
We explore the relationship among experimental design, parameter estimation, and systematic error in sloppy models. We show that the approximate nature of mathematical models poses challenges for experimental design in sloppy models. In many models of complex biological processes it is unknown what are the relevant physical mechanisms that must be included to explain system behaviors. As a consequence, models are often overly complex, with many practically unidentifiable parameters. Furthermore, which mechanisms are relevant/irrelevant vary among experiments. By selecting complementary experiments, experimental design may inadvertently make details that were ommitted from the model become relevant. When this occurs, the model will have a large systematic error and fail to give a good fit to the data. We use a simple hyper-model of model error to quantify a model’s discrepancy and apply it to two models of complex biological processes (EGFR signaling and DNA repair) with optimally selected experiments. We find that although parameters may be accurately estimated, the discrepancy in the model renders it less predictive than it was in the sloppy regime where systematic error is small. We introduce the concept of a sloppy system–a sequence of models of increasing complexity that become sloppy in the limit of microscopic accuracy. We explore the limits of accurate parameter estimation in sloppy systems and argue that identifying underlying mechanisms controlling system behavior is better approached by considering a hierarchy of models of varying detail rather than focusing on parameter estimation in a single model. PMID:27923060
NASA Astrophysics Data System (ADS)
Chen, L.; Tang, Y. J.; Song, M.; Shi, J.; Ren, L.
2013-11-01
Since the introduction of superconducting fault current limiter (SFCL) into electrical distribution system may be a good choice with economy and practicability, the parameter design and current-limiting characteristics of a 10 kV voltage compensation type active SFCL are studied in this paper. Firstly, the SFCL’s circuit structure and operation principle are presented. Then, taking a practical 10 kV distribution system as its application object, the SFCL’s basic parameters are designed to meet the system requirements. Further, using MATLAB, the detailed current-limiting performances of the 10 kV active SFCL are simulated under different fault conditions. The simulation results show that the active SFCL can deal well with the faults, and the parameter design’s suitability can be testified. At the end, in view of the engineering feasibility of the 10 kV active SFCL, some preliminary discussions are carried out.
Mantry, Sisir; Mishra, Barada K.; Chakraborty, Madhusudan
2013-01-01
This paper presents the application of the Taguchi experimental design in developing nanostructured yittria stabilized zirconia (YSZ) coatings by plasma spraying process. This paper depicts dependence of adhesion strength of as-sprayed nanostructured YSZ coatings on various process parameters, and effect of those process parameters on performance output has been studied using Taguchi's L16 orthogonal array design. Particle velocities prior to impacting the substrate, stand-off-distance, and particle temperature are found to be the most significant parameter affecting the bond strength. To achieve retention of nanostructure, molten state of nanoagglomerates (temperature and velocity) has been monitored using particle diagnostics tool. Maximum adhesion strength of 40.56 MPa has been experimentally found out by selecting optimum levels of selected factors. The enhanced bond strength of nano-YSZ coating may be attributed to higher interfacial toughness due to cracks being interrupted by adherent nanozones. PMID:24288490
NASA Astrophysics Data System (ADS)
Sun, Hongyue; Luo, Shuai; Jin, Ran; He, Zhen
2017-07-01
Mathematical modeling is an important tool to investigate the performance of microbial fuel cell (MFC) towards its optimized design. To overcome the shortcoming of traditional MFC models, an ensemble model is developed through integrating both engineering model and statistical analytics for the extrapolation scenarios in this study. Such an ensemble model can reduce laboring effort in parameter calibration and require fewer measurement data to achieve comparable accuracy to traditional statistical model under both the normal and extreme operation regions. Based on different weight between current generation and organic removal efficiency, the ensemble model can give recommended input factor settings to achieve the best current generation and organic removal efficiency. The model predicts a set of optimal design factors for the present tubular MFCs including the anode flow rate of 3.47 mL min-1, organic concentration of 0.71 g L-1, and catholyte pumping flow rate of 14.74 mL min-1 to achieve the peak current at 39.2 mA. To maintain 100% organic removal efficiency, the anode flow rate and organic concentration should be controlled lower than 1.04 mL min-1 and 0.22 g L-1, respectively. The developed ensemble model can be potentially modified to model other types of MFCs or bioelectrochemical systems.
Agarabi, Cyrus D; Schiel, John E; Lute, Scott C; Chavez, Brittany K; Boyne, Michael T; Brorson, Kurt A; Khan, Mansoora; Read, Erik K
2015-06-01
Consistent high-quality antibody yield is a key goal for cell culture bioprocessing. This endpoint is typically achieved in commercial settings through product and process engineering of bioreactor parameters during development. When the process is complex and not optimized, small changes in composition and control may yield a finished product of less desirable quality. Therefore, changes proposed to currently validated processes usually require justification and are reported to the US FDA for approval. Recently, design-of-experiments-based approaches have been explored to rapidly and efficiently achieve this goal of optimized yield with a better understanding of product and process variables that affect a product's critical quality attributes. Here, we present a laboratory-scale model culture where we apply a Plackett-Burman screening design to parallel cultures to study the main effects of 11 process variables. This exercise allowed us to determine the relative importance of these variables and identify the most important factors to be further optimized in order to control both desirable and undesirable glycan profiles. We found engineering changes relating to culture temperature and nonessential amino acid supplementation significantly impacted glycan profiles associated with fucosylation, β-galactosylation, and sialylation. All of these are important for monoclonal antibody product quality. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.
NASA Astrophysics Data System (ADS)
Evstigneev, Vladislav P.; Pashkova, Irina S.; Kostjukov, Viktor V.; Hernandez Santiago, Adrian A.; Evstigneev, Maxim P.
2016-11-01
The principal condition for optimal experiment design, required for getting reasonable error for equilibrium aggregation constant, K, determination is obtained. This condition states that the selected concentration range for performing titration experiment should be inversely proportional to the expected value of K. As a consequence, the choice of physico-chemical methods for determination of aggregation parameters must obey this condition.
NASA Technical Reports Server (NTRS)
Fisher, Lloyd J; Hoffman, Edward L
1958-01-01
Data from ditching investigations conducted at the Langley Aeronautical Laboratory with dynamic scale models of various airplanes are presented in the form of tables. The effects of design parameters on the ditching characteristics of airplanes, based on scale-model investigations and on reports of full-scale ditchings, are discussed. Various ditching aids are also discussed as a means of improving ditching behavior.
Influence of design and mode parameters on pump performance curve of heat generating aggregate
NASA Astrophysics Data System (ADS)
Barykin, O.; Kovalyov, S.; Ovcharenko, M.; Papchenko, A.
2017-08-01
Classification of multi-functional heat generating aggregates according to the function is considered in this article. Analysis of operating process mathematical model was implemented and methods for its refinement were proposed. Results of physical investigation of heat generating aggregate design and mode parameters influence on its power and head were presented.
Westine, Carl D; Spybrook, Jessaca; Taylor, Joseph A
2013-12-01
Prior research has focused primarily on empirically estimating design parameters for cluster-randomized trials (CRTs) of mathematics and reading achievement. Little is known about how design parameters compare across other educational outcomes. This article presents empirical estimates of design parameters that can be used to appropriately power CRTs in science education and compares them to estimates using mathematics and reading. Estimates of intraclass correlations (ICCs) are computed for unconditional two-level (students in schools) and three-level (students in schools in districts) hierarchical linear models of science achievement. Relevant student- and school-level pretest and demographic covariates are then considered, and estimates of variance explained are computed. Subjects: Five consecutive years of Texas student-level data for Grades 5, 8, 10, and 11. Science, mathematics, and reading achievement raw scores as measured by the Texas Assessment of Knowledge and Skills. Results: Findings show that ICCs in science range from .172 to .196 across grades and are generally higher than comparable statistics in mathematics, .163-.172, and reading, .099-.156. When available, a 1-year lagged student-level science pretest explains the most variability in the outcome. The 1-year lagged school-level science pretest is the best alternative in the absence of a 1-year lagged student-level science pretest. Science educational researchers should utilize design parameters derived from science achievement outcomes. © The Author(s) 2014.
Design Parameters of Paraboloid-Hyperboloid Telescopes for X-ray Astronomy.
Vanspeybroeck, L P; Chase, R C
1972-02-01
We have evaluated the principal optical characteristics of paraboloid-hyperboloid x-ray telescopes by a ray-tracing procedure; we find that our results for resolution, focal plane curvature, and finite source distance effects may be approximated in terms of the design parameters by simple empirical formulas.
Design parameters of paraboloid-hyperboloid telescopes for X-ray astronomy.
NASA Technical Reports Server (NTRS)
Vanspeybroeck, L. P.; Chase, R. C.
1972-01-01
A systematic evaluation has been made of the principal optical properties of paraboloid-hyperboloid X-ray telescopes using a ray-tracing procedure. It has been found that the results obtained for resolution, focal plane curvature, and finite source distance effects may be approximated in terms of the design parameters by simple empirical formulas.
Van Derlinden, E; Bernaerts, K; Van Impe, J F
2010-05-21
Optimal experiment design for parameter estimation (OED/PE) has become a popular tool for efficient and accurate estimation of kinetic model parameters. When the kinetic model under study encloses multiple parameters, different optimization strategies can be constructed. The most straightforward approach is to estimate all parameters simultaneously from one optimal experiment (single OED/PE strategy). However, due to the complexity of the optimization problem or the stringent limitations on the system's dynamics, the experimental information can be limited and parameter estimation convergence problems can arise. As an alternative, we propose to reduce the optimization problem to a series of two-parameter estimation problems, i.e., an optimal experiment is designed for a combination of two parameters while presuming the other parameters known. Two different approaches can be followed: (i) all two-parameter optimal experiments are designed based on identical initial parameter estimates and parameters are estimated simultaneously from all resulting experimental data (global OED/PE strategy), and (ii) optimal experiments are calculated and implemented sequentially whereby the parameter values are updated intermediately (sequential OED/PE strategy). This work exploits OED/PE for the identification of the Cardinal Temperature Model with Inflection (CTMI) (Rosso et al., 1993). This kinetic model describes the effect of temperature on the microbial growth rate and encloses four parameters. The three OED/PE strategies are considered and the impact of the OED/PE design strategy on the accuracy of the CTMI parameter estimation is evaluated. Based on a simulation study, it is observed that the parameter values derived from the sequential approach deviate more from the true parameters than the single and global strategy estimates. The single and global OED/PE strategies are further compared based on experimental data obtained from design implementation in a bioreactor
NASA Technical Reports Server (NTRS)
Rizk, Magdi H.
1988-01-01
This user's manual is presented for an aerodynamic optimization program that updates flow variables and design parameters simultaneously. The program was developed for solving constrained optimization problems in which the objective function and the constraint function are dependent on the solution of the nonlinear flow equations. The program was tested by applying it to the problem of optimizing propeller designs. Some reference to this particular application is therefore made in the manual. However, the optimization scheme is suitable for application to general aerodynamic design problems. A description of the approach used in the optimization scheme is first presented, followed by a description of the use of the program.
Bernaerts, K; Versyck, K J; Van Impe, J F
2000-03-10
It is generally known that accurate model building, i.e., proper model structure selection and reliable parameter estimation, constitutes an essential matter in the field of predictive microbiology, in particular, when integrating these predictive models in food safety systems. In this context, Versyck et al. (1999) have introduced the methodology of optimal experimental design techniques for parameter estimation within the field. Optimal experimental design focuses on the development of optimal input profiles such that the resulting rich (i.e., highly informative) experimental data enable unique model parameter estimation. As a case study, Versyck et al. (1999) [Versyck, K., Bernaerts, K., Geeraerd, A.H., Van Impe, J.F., 1999. Introducing optimal experimental design in predictive modeling: a motivating example. Int. J. Food Microbiol., 51(1), 39-51] have elaborated the estimation of Bigelow inactivation kinetics parameters (in a numerical way). Opposed to the classic (static) experimental approach in predictive modelling, an optimal dynamic experimental setup is presented. In this paper, the methodology of optimal experimental design or parameter estimation is applied to obtain uncorrelated estimates of the square root model parameters [Ratkowsky, D.A., Olley, J., McMeekin, T.A., Ball, A., 1982. Relationship between temperature and growth rate of bacterial cultures. J. Bacteriol. 149, 1-5] describing the effect of suboptimal growth temperatures on the maximum specific growth rate of microorganisms. These estimates are the direct result of fitting a primary growth model to cell density measurements as a function of time. Apart from the design of an optimal time-varying temperature profile based on a sensitivity study of the model output, an important contribution of this publication is a first experimental validation of this innovative dynamic experimental approach for uncorrelated parameter identification. An optimal step temperature profile, within the range of
Interdependence of parameters important to the design of subsonic canard-configured aircraft
NASA Technical Reports Server (NTRS)
Feistel, T. W.
1985-01-01
An analysis is made of the interrelationship of the longitudinal parameters important to the aerodynamic design of an efficient canard or tandem wing configuration. It is shown that theoretical configuration span efficiencies substantially greater than one are feasible with the proper choice of parameters. This improvement can translate into significantly increased lift/drag ratios assuming fixed spans. The Prandtl-Munk relationship for induced drag is used as a convenient qualitative guide, with stability and trim criteria superimposed. An 'aspect-ratio ratio' parameter is introduced to aid in optimizing a configuration longitudinally. It is shown that a canard/wing 'aspect-ratio ratio' of approximately 3/2 to 2 is necessary to achieve peak span efficiency for a given span ratio and gap, assuming representative parameters.
NASA Technical Reports Server (NTRS)
Turso, James A.; Litt, Jonathan S.
2004-01-01
A method for accommodating engine deterioration via a scheduled Linear Parameter Varying Quadratic Lyapunov Function (LPVQLF)-Based controller is presented. The LPVQLF design methodology provides a means for developing unconditionally stable, robust control of Linear Parameter Varying (LPV) systems. The controller is scheduled on the Engine Deterioration Index, a function of estimated parameters that relate to engine health, and is computed using a multilayer feedforward neural network. Acceptable thrust response and tight control of exhaust gas temperature (EGT) is accomplished by adjusting the performance weights on these parameters for different levels of engine degradation. Nonlinear simulations demonstrate that the controller achieves specified performance objectives while being robust to engine deterioration as well as engine-to-engine variations.
A Parts Database with Consensus Parameter Estimation for Synthetic Circuit Design.
Huynh, Linh; Tagkopoulos, Ilias
2016-12-16
Mathematical modeling and numerical simulation are crucial to support design decisions in synthetic biology. Accurate estimation of parameter values is key, as direct experimental measurements are difficult and time-consuming. Insufficient data, incompatible measurements, and specialized models that lack universal parameters make this task challenging. Here, we have created a database (PAMDB) that integrates data from 135 publications that contain 118 circuits and 165 genetic parts of the bacterium Escherichia coli. We used a succinct, universal model formulation to describe the part behavior in each circuit. We introduce a constrained consensus inference method that was used to infer the value of the model parameters and evaluated its performance through cross-validation in a benchmark of 23 circuits. We discuss these results and summarize the challenges in data integration and parameter inference. This work provides a resource and a methodology that can be used as a point of reference for synthetic circuit modeling.
The MANIFEST prototyping design study
NASA Astrophysics Data System (ADS)
Lawrence, Jonathan S.; Ben-Ami, Sagi; Brown, David M.; Brown, Rebecca A.; Case, Scott; Chapman, Steve; Churilov, Vladimir; Colless, Matthew; Content, Robert; Depoy, Darren; Evans, Ian; Farrell, Tony; Goodwin, Michael; Jacoby, George; Klauser, Urs; Kuehn, Kyler; Lorente, Nuria P. F.; Mali, Slavko; Marshall, Jennifer; Muller, Rolf; Nichani, Vijay; Pai, Naveen; Prochaska, Travis; Saunders, Will; Schmidt, Luke; Shortridge, Keith; Staszak, Nicholas F.; Szentgyorgyi, Andrew; Tims, Julia; Vuong, Minh V.; Waller, Lewis G.; Zhelem, Ross
2016-08-01
MANIFEST is a facility multi-object fibre system for the Giant Magellan Telescope, which uses `Starbug' fibre positioning robots. MANIFEST, when coupled to the telescope's planned seeing-limited instruments, GMACS, and G-CLEF, offers access to: larger fields of view; higher multiplex gains; versatile reformatting of the focal plane via IFUs; image-slicers; and in some cases higher spatial and spectral resolution. The Prototyping Design Study phase for MANIFEST, nearing completion, has focused on developing a working prototype of a Starbugs system, called TAIPAN, for the UK Schmidt Telescope, which will conduct a stellar and galaxy survey of the Southern sky. The Prototyping Design Study has also included work on the GMT instrument interfaces. In this paper, we outline the instrument design features of TAIPAN, highlight the modifications that will be necessary for the MANIFEST implementation, and provide an update on the MANIFEST/instrument interfaces.
Learning effects in the block design task: a stimulus parameter-based approach.
Miller, Joseph C; Ruthig, Joelle C; Bradley, April R; Wise, Richard A; Pedersen, Heather A; Ellison, Jo M
2009-12-01
Learning effects were assessed for the block design (BD) task, on the basis of variation in 2 stimulus parameters: perceptual cohesiveness (PC) and set size uncertainty (U). Thirty-one nonclinical undergraduate students (19 female) each completed 3 designs for each of 4 varied sets of the stimulus parameters (high-PC/high-U, high-PC/low-U, low-PC/high-U, and low-PC/low-U), ordered randomly within a larger set of designs with mixed stimulus characteristics. Regression analyses revealed significant, although modest, learning effects in all conditions. Negative-logarithmic learning slopes (growth factors) were greatest for high-U/high-PC designs and smallest for low-U/low-PC designs. Comparison of these slopes with known Wechsler Adult Intelligence Scale (3rd ed.; D. Wechsler, 1997; and 4th ed.; D. Wechsler, 2008) BD subtest gain scores demonstrated that presenting novel test items matched on stimulus parameters in multiple administrations reduced learning effects compared with the repeated use of the same test items. The results suggest that repeated administration of novel test items of the BD subtest, matched for PC and U, would result in more accurate assessments of changes in examinees' abilities over time than would the use of the same items. Difficulties inherent in implementing this method are also discussed.
Design of a multi beam klystron cavity from its single beam parameters
NASA Astrophysics Data System (ADS)
Kant, Deepender; Joshi, L. M.; Janyani, Vijay
2016-03-01
The klystron is a well-known microwave amplifier which uses kinetic energy of an electron beam for amplification of the RF signal. There are some limitations of conventional single beam klystron such as high operating voltage, low efficiency and bulky size at higher power levels, which are very effectively handled in Multi Beam Klystron (MBK) that uses multiple low purveyance electron beams for RF interaction. Each beam propagates along its individual transit path through a resonant cavity structure. Multi-Beam klystron cavity design is a critical task due to asymmetric cavity structure and can be simulated by 3D code only. The present paper shall discuss the design of multi beam RF cavities for klystrons operating at 2856 MHz (S-band) and 5 GHz (C-band) respectively. The design approach uses some scaling laws for finding the electron beam parameters of the multi beam device from their single beam counter parts. The scaled beam parameters are then used for finding the design parameters of the multi beam cavities. Design of the desired multi beam cavity can be optimized through iterative simulations in CST Microwave Studio.
Design of a multi beam klystron cavity from its single beam parameters
Kant, Deepender Joshi, L. M.; Janyani, Vijay
2016-03-09
The klystron is a well-known microwave amplifier which uses kinetic energy of an electron beam for amplification of the RF signal. There are some limitations of conventional single beam klystron such as high operating voltage, low efficiency and bulky size at higher power levels, which are very effectively handled in Multi Beam Klystron (MBK) that uses multiple low purveyance electron beams for RF interaction. Each beam propagates along its individual transit path through a resonant cavity structure. Multi-Beam klystron cavity design is a critical task due to asymmetric cavity structure and can be simulated by 3D code only. The present paper shall discuss the design of multi beam RF cavities for klystrons operating at 2856 MHz (S-band) and 5 GHz (C-band) respectively. The design approach uses some scaling laws for finding the electron beam parameters of the multi beam device from their single beam counter parts. The scaled beam parameters are then used for finding the design parameters of the multi beam cavities. Design of the desired multi beam cavity can be optimized through iterative simulations in CST Microwave Studio.
NASA Astrophysics Data System (ADS)
Zhu, H. G.; Zhang, R. T.; Xia, J.; Zhou, H. B.; Tang, X. C.
2013-12-01
Shaft tubular pumping systems with straight discharge passage are more widely adopted because they possesses many advantages such as easier installation of pump sets, better ventilation for motor and transmission devices, open access to inspect pump sets and lower cost for maintenance. The design parameters of a straight discharge passage will directly affect hydraulic loss and energy performance of the shaft pumping system. The optimal hydraulic design of discharge passages is carried out under the guideline of Pump Station Design Code to satisfy optimal design objectives. Computational fluid dynamics is applied to simulate the internal flow of a shaft pumping system the influence of its design parameter on the system performance is investigated. Keeping the shaft and suction box unchanged, six discharge passage design schemes with different length and outlet width are compared based on CFD to analyze the internal flow fields and their energy performances are predicted. The computed results indicate that when the outlet width of discharge passage is fixed, the longer the discharge passage, the better the internal flow fields with smaller backflow and vortex zone inside the passage. When the length of discharge passage is determined, the axial velocity distribution uniformity and bias angle in the outlet section will vary with the value of the outlet width. Optimal hydraulic design of discharge passages can achieve better internal flow and higher pumping efficiency.
Drift parameters optimization of a TPC polarimeter: a simulation study
NASA Astrophysics Data System (ADS)
Rakhee, K.; Radhakrishna, V.; Koushal, V.; Baishali, G.; Vinodkumar, A. M.
2015-06-01
Time Projection Chamber (TPC) based X-ray polarimeters using Gas Electron Multiplier (GEM) are currently being developed to make sensitive measurement of polarization in 2-10 keV energy range. The emission direction of the photoelectron ejected via photoelectric effect carries the information of the polarization of the incident X-ray photon. Performance of a gas based polarimeter is affected by the operating drift parameters such as gas pressure, drift field and drift-gap. We present simulation studies carried out in order to understand the effect of these operating parameters on the modulation factor of a TPC polarimeter. Models of Garfield are used to study photoelectron interaction in gas and drift of electron cloud towards GEM. Our study is aimed at achieving higher modulation factors by optimizing drift parameters. Study has shown that Ne/DME (50/50) at lower pressure and drift field can lead to desired performance of a TPC polarimeter.
NASA Astrophysics Data System (ADS)
Prilutskii, A. I.; Prilutskii, I. K.; Makoveeva, A. S.; Prilutskii, A. A.
2017-08-01
The article deals with some improper performance reasons of reciprocating compressors which are in year-round operation. The possibilities and recommendations for design optimization of some details and components and compressor operating parameters under existing industry conditions by means of the upgraded volumetric machine calculation program KOMDET-M designed for analyzing processes occurring in volumetric machines are represented. The calculation result agreement with parameters claimed by vendor and actual ones of gas reciprocating compressors which are in operation is shown. The scientific and practical value of the research for any designed, upgradable or operating unit is demonstrated. Necessary calculations have been performed by means of the application calculation program. Some examples of volumetric machine reliability and efficiency improvement are represented.
NASA Technical Reports Server (NTRS)
Subramanyam, Guru; VanKeuls, Fred W.; Miranda, Felix A.; Canedy, Chadwick L.; Aggarwal, Sanjeev; Venkatesan, Thirumalai; Ramesh, Ramamoorthy
2000-01-01
The correlation of electric field and critical design parameters such as the insertion loss, frequency ability return loss, and bandwidth of conductor/ferroelectric/dielectric microstrip tunable K-band microwave filters is discussed in this work. This work is based primarily on barium strontium titanate (BSTO) ferroelectric thin film based tunable microstrip filters for room temperature applications. Two new parameters which we believe will simplify the evaluation of ferroelectric thin films for tunable microwave filters, are defined. The first of these, called the sensitivity parameter, is defined as the incremental change in center frequency with incremental change in maximum applied electric field (EPEAK) in the filter. The other, the loss parameter, is defined as the incremental or decremental change in insertion loss of the filter with incremental change in maximum applied electric field. At room temperature, the Au/BSTO/LAO microstrip filters exhibited a sensitivity parameter value between 15 and 5 MHz/cm/kV. The loss parameter varied for different bias configurations used for electrically tuning the filter. The loss parameter varied from 0.05 to 0.01 dB/cm/kV at room temperature.
AFE ion mass spectrometer design study
NASA Technical Reports Server (NTRS)
Wright, Willie
1989-01-01
This final technical report covers the activities engaged in by the University of Texas at Dallas, Center for Space Sciences in conjunction with the NASA Langley Research Center, Systems Engineering Division in design studies directed towards defining a suitable ion mass spectrometer to determine the plasma parameter around the Aeroassisted Flight Experiment vehicle during passage through the earth's upper atmosphere. Additional studies relate to the use of a Langmuir probe to measure windward ion/electron concentrations and temperatures. Selected instrument inlet subsystems were tested in the NASA Ames Arc-Jet Facility.
AFE ion mass spectrometer design study
NASA Astrophysics Data System (ADS)
Wright, Willie
1989-03-01
This final technical report covers the activities engaged in by the University of Texas at Dallas, Center for Space Sciences in conjunction with the NASA Langley Research Center, Systems Engineering Division in design studies directed towards defining a suitable ion mass spectrometer to determine the plasma parameter around the Aeroassisted Flight Experiment vehicle during passage through the earth's upper atmosphere. Additional studies relate to the use of a Langmuir probe to measure windward ion/electron concentrations and temperatures. Selected instrument inlet subsystems were tested in the NASA Ames Arc-Jet Facility.
Controller design for wind turbine load reduction via multiobjective parameter synthesis
NASA Astrophysics Data System (ADS)
Hoffmann, A. F.; Weiβ, F. A.
2016-09-01
During the design process for a wind turbine load reduction controller many different, sometimes conflicting requirements must be fulfilled simultaneously. If the requirements can be expressed as mathematical criteria, such a design problem can be solved by a criterion-vector and multi-objective design optimization. The software environment MOPS (Multi-Objective Parameter Synthesis) supports the engineer for such a design optimization. In this paper MOPS is applied to design a multi-objective load reduction controller for the well-known DTU 10 MW reference wind turbine. A significant reduction in the fatigue criteria especially the blade damage can be reached by the use of an additional Individual Pitch Controller (IPC) and an additional tower damper. This reduction is reached as a trade-off with an increase of actuator load.
Parameter studies using an IDL model of the FORTE trigger box
Murphy, T.
1996-06-01
The author presents the results of parameter studies designed to estimate the optimum settings for the trigger circuit which will be used by the fast on-orbit recording of transient events (FORTE) satellite. Real broadband data recorded by the Los Alamos Blackbeard experiment was processed by a computer model that simulated the action of the FORTE trigger. The probability of detection and false-event rate was determined for a variety of trigger-parameter settings, and the results are presented in the report. The result of the study is a well-defined set of parameters chosen to give the best possible triggering performance.
Review Study on Runway Capacity Parameters and Improvement
NASA Astrophysics Data System (ADS)
Safrilah; Putra, J. C. P.
2017-06-01
The demand of air travel continues to increase over time, due to its short travel time, reliability and safety. Problems then arise when airport capacity, especially airside (mainly runway) capacity cannot cope with the demand. Some airports build the expensive additional infrastructure, while some others believe that manage on system is more efficient and effective. The study gathering information from various source about parameters related to runway capacity so that the improvement made in the future will solve right on target. To accommodate wide number of factors, the study classify the parameters into five categories in which operation/procedure related parameters play an important role (52%). To facilitate future research on runway capacity, the study also tabulates methods used by various scholars to improve runway capacity
The Study of Diagnostic Efficacy of Nerve Conduction Study Parameters in Cervical Radiculopathy
Pawar, Sachin; Kashikar, Aditi; Shende, Vinod; Waghmare, Satish
2013-01-01
Background: Cervical Radiculopathy (CR) is a neurologic condition characterised by dysfunction of a cervical spinal nerve, the roots of the nerve, or both. Diagnostic criteria for CR are not well defined, and no universally accepted criteria for its diagnosis have been established. Clinical examination, radiological imaging and electrophysiologic evaluation are the different modalities to diagnose CR. The incidence of Cervical Spondylosis and related conditions is increasing in the present scenario and the use of radiologic examination is time consuming and uneconomical for the common Indian setup. Thus, there is a definite need to establish a cost effective, reliable, and accurate means for establishing the diagnosis of cervical radiculopathy. Electrodiagnostic tests are the closest to fulfill these criteria. Aim: To evaluate diagnostic utility of various motor and sensory nerve conduction study parameters in cervical radiculopathy. Setting and Design: It was a cross-sectional study conducted on 100 subjects of age > 40 years. Material and Methods: The consecutive patients clinically diagnosed to have cervical radiculopathy, referred from department of Orthopaedics were prospectively recruited for the motor and sensory nerve conduction study using RMS EMG EP Mark-II. Parameters studied were Compound Muscle Action Potential (CMAP), Distal Motor Latency (DML) and Conduction Velocity (CV) for motor nerves and Sensory Nerve Action Potential (SNAP) and CV for sensory nerves. Statistical Analysis: Study observations and results were analysed to find the Specificity, Sensitivity, Positive Predictive Value and Negative Predictive Value using SPSS 16.0. Results: Among various motor nerve conduction parameters CMAP was found to be more sensitive with high positive predicative value. CV was found to have greater specificity and DML had least negative predictive value. Sensory nerve conduction parameters were found to have less sensitivity but higher specificity as compared
Nonperturbative study of the action parameters for anisotropic-lattice quarks
Foley, Justin; Cais, Alan O; Peardon, Mike; Ryan, Sinead M.
2006-01-01
A quark action designed for highly anisotropic-lattice simulations is discussed. The mass-dependence of the parameters in the action is studied and the results are presented. Applications of this action in studies of heavy quark quantities are described and results are presented from simulations at an anisotropy of six, for a range of quark masses from strange to bottom.
NASA Astrophysics Data System (ADS)
Mohamed, Omar Ahmed; Masood, Syed Hasan; Bhowmik, Jahar Lal; Nikzad, Mostafa; Azadmanjiri, Jalal
2016-07-01
In fused deposition modeling (FDM) additive manufacturing process, it is often difficult to determine the actual levels of process parameters in order to achieve the best dynamic mechanical properties of FDM manufactured part. This is mainly due to the large number of FDM parameters and a high degree of interaction between the parameters affecting such properties. This requires a large number of experiments to be determined. This paper presents a study on the influence of six FDM process parameters (layer thickness, air gap, raster angle, build orientation, road width, and number of contours) on the dynamic mechanical properties of the FDM manufactured parts using the fraction factorial design. The most influential parameters were statistically obtained through the analysis of variance (ANOVA) technique, and the results indicate that the layer thickness, the air gap, and the number of contours have the largest impact on dynamic mechanical properties. The optimal parameters for maximum dynamic mechanical properties were found to be layer thickness of 0.3302 mm, air gap of 0.00 mm, raster angle of 0.0°, build orientation of 0.0°, road width of 0.4572 mm, and 10 contours. Finally, a confirmation experiment was performed using optimized levels of process parameters, which showed good fit with the estimated values.
Effect of process design and operating parameters on aerobic methane oxidation in municipal WWTPs.
Daelman, Matthijs R J; Van Eynde, Tamara; van Loosdrecht, Mark C M; Volcke, Eveline I P
2014-12-01
Methane is a potent greenhouse gas and its emission from municipal wastewater treatment plants (WWTPs) should be prevented. One way to do this is to promote the biological conversion of dissolved methane over stripping in aeration tanks. In this study, the well-established Activated Sludge Model n°1 (ASM1) and Benchmark Simulation Model n°1 (BSM1) were extended to study the influence of process design and operating parameters on biological methane oxidation. The aeration function used in BSM 1 was upgraded to more accurately describe gas-liquid transfer of oxygen and methane in aeration tanks equipped with subsurface aeration. Dissolved methane could be effectively removed in an aeration tank at an aeration rate that is in agreement with optimal effluent quality. Subsurface bubble aeration proved to be better than surface aeration, while a CSTR configuration was superior to plug flow conditions in avoiding methane emissions. The conversion of methane in the activated sludge tank benefits from higher methane concentrations in the WWTP's influent. Finally, if an activated sludge tank is aerated with methane containing off-gas, a limited amount of methane is absorbed and converted in the mixed liquor. This knowledge helps to stimulate the methane oxidizing capacity of activated sludge in order to abate methane emissions from wastewater treatment to the atmosphere.
Three-parameter optical studies in Scottish coastal waters
NASA Astrophysics Data System (ADS)
McKee, David; Cunningham, Alex; Jones, Ken
1997-02-01
A new submersible optical instrument has been constructed which allows chlorophyll fluorescence, attenuation and wide- angle scattering measurements to be made simultaneously at he same point in a body of water. The instrument sues a single xenon flashlamp as the light source, and incorporates its own power supply and microprocessor based data logging system. It has ben cross-calibrated against commercial single-parameter instruments using a range of non-algal particles and phytoplankton cultures. The equipment has been deployed at sea in the Firth of Clyde and Loch Linnhe, where is has been used to study seasonal variability in optical water column structure. Results will be presented to illustrate how ambiguity in the interpretation of measurements of a single optical parameter can be alleviated by measuring several parameters simultaneously. Comparative studies of differences in winter and spring relationships between optical variable shave also ben carried out.
Liquid belt radiator design study
NASA Technical Reports Server (NTRS)
Teagan, W. P.; Fitzgerald, K. F.
1986-01-01
The Liquid Belt Radiator (LBR) is an advanced concept developed to meet the needs of anticipated future space missions. A previous study documented the advantages of this concept as a lightweight, easily deployable alternative to present day space heat rejection systems. The technical efforts associated with this study concentrate on refining the concept of the LBR as well as examining the issues of belt dynamics and potential application of the LBR to intermediate and high temperature heat rejection applications. A low temperature point design developed in previous work is updated assuming the use of diffusion pump oil, Santovac-6, as the heat transfer media. Additional analytical and design effort is directed toward determining the impact of interface heat exchanger, fluid bath sealing, and belt drive mechanism designs on system performance and mass. The updated design supports the earlier result by indicating a significant reduction in system specific system mass as compared to heat pipe or pumped fluid radiator concepts currently under consideration (1.3 kg/sq m versus 5 kg/sq m).
Human factors engineering design review acceptance criteria for the safety parameter display
McGevna, V.; Peterson, L.R.
1981-10-02
This report contains human factors engineering design review acceptance criteria developed by the Human Factors Engineering Branch (HFEB) of the Nuclear Regulatory Commission (NRC) to use in evaluating designs of the Safety Parameter Display System (SPDS). These criteria were developed in response to the functional design criteria for the SPDS defined in NUREG-0696, Functional Criteria for Emergency Response Facilities. The purpose of this report is to identify design review acceptance criteria for the SPDS installed in the control room of a nuclear power plant. Use of computer driven cathode ray tube (CRT) displays is anticipated. General acceptance criteria for displays of plant safety status information by the SPDS are developed. In addition, specific SPDS review criteria corresponding to the SPDS functional criteria specified in NUREG-0696 are established.
NASA Astrophysics Data System (ADS)
Tokunaga, Yoshitaka; Kubota, Kunihiro
This paper presents estimation techniques of machine parameters for two windings power transformer using design procedure of winding structure. Especially, it is very difficult to obtain machine parameters for transformers in customers' facilities. Using estimation techniques, machine parameters could be calculated from the only nameplate data of these transformers. Subsequently, EMTP-ATP simulation of the inrush current was carried out using machine parameters estimated by design procedure of winding structure and simulation results were reproduced measured waveforms.
Improvement of plant parameters of the ROBO gamma irradiation facility due to design modification
NASA Astrophysics Data System (ADS)
Kovacs, A.; Moussa, A.; Othman, I.; Del Valle Odar, C.; Seminario, A.; Linares, M.; Huamanlazo, P.; Aymar, J.; Chu, R.
1998-06-01
Two industrial scale, "ROBO" type 60Co gamma irradiation facilities have recently been put into operation in Syria and Peru, and the dosimetry commissioning of both plants have been carried out to determine dose distribution within products and to calculate plant parameters such as efficiency, dose uniformity ratio and throughput. There are some design modifications between the two plants in connection with the location of the carriers with respect to the source plaque and also to each other. The effect of these construction modifications on the plant parameters is discussed in the analysis of the dose distribution data measured in the carriers with depth and height among the four irradiation rows on both sides of the source plaque. The plant parameters were also calculated for different product densities using the technical data of the facilities, and the calculated and measured results were compared to each other.
Optimal Design of Material and Process Parameters in Powder Injection Molding
NASA Astrophysics Data System (ADS)
Ayad, G.; Barriere, T.; Gelin, J. C.; Song, J.; Liu, B.
2007-04-01
The paper is concerned with optimization and parametric identification for the different stages in Powder Injection Molding process that consists first in injection of powder mixture with polymer binder and then to the sintering of the resulting powders part by solid state diffusion. In the first part, one describes an original methodology to optimize the process and geometry parameters in injection stage based on the combination of design of experiments and an adaptive Response Surface Modeling. Then the second part of the paper describes the identification strategy that one proposes for the sintering stage, using the identification of sintering parameters from dilatometeric curves followed by the optimization of the sintering process. The proposed approaches are applied to the optimization of material and process parameters for manufacturing a ceramic femoral implant. One demonstrates that the proposed approach give satisfactory results.
General parameter relations for the Shinnar-Le Roux pulse design algorithm.
Lee, Kuan J
2007-06-01
The magnetization ripple amplitudes from a pulse designed by the Shinnar-Le Roux algorithm are a non-linear function of the Shinnar-Le Roux A and B polynomial ripples. In this paper, the method of Pauly et al. [J. Pauly, P. Le Roux, D. Nishimura, A. Macovski, Parameter relations for the Shinnar-Le Roux selective excitation pulse design algorithm, IEEE Transactions on Medical Imaging 10 (1991) 56-65.] has been extended to derive more general parameter relations. These relations can be used for cases outside the five classes considered by Pauly et al., in particular excitation pulses for flip angles that are not small or 90 degrees. Use of the new relations, together with an iterative procedure to obtain polynomials with the specified ripples from the Parks-McClellan algorithm, are shown to give simulated slice profiles that have the desired ripple amplitudes.
Numerical method to determine mechanical parameters of engineering design in rock masses.
Xue, Ting-He; Xiang, Yi-Qiang; Guo, Fa-Zhong
2004-07-01
This paper proposes a new continuity model for engineering in rock masses and a new schematic method for reporting the engineering of rock continuity. This method can be used to evaluate the mechanics of every kind of medium; and is a new way to determine the mechanical parameters used in engineering design in rock masses. In the numerical simulation, the experimental parameters of intact rock were combined with the structural properties of field rock. The experimental results for orthogonally-jointed rock are given. The results included the curves of the stress-strain relationship of some rock masses, the curve of the relationship between the dimension Delta and the uniaxial pressure-resistant strength sc of these rock masses, and pictures of the destructive procedure of some rock masses in uniaxial or triaxial tests, etc. Application of the method to engineering design in rock masses showed the potential of its application to engineering practice.
Design of GLP lab environment parameters monitor system based on Schneider PLC
NASA Astrophysics Data System (ADS)
Lian, Xiaoqin; Xu, Huihui; Duan, Zhengang; Zhang, Yong
2008-10-01
According to the technological process and the requirement for system control of the GLP Laboratory, an automatic system is designed to monitor and control over the environment parameters of the GLP laboratory. The system is composed of a programmable controller and touching screen as the processing unit. The Schneider PLC TSX P57303 controller with its counterpart input/output modules is adopted as the hardware platform and the Schneider PL7-MICRO/WIN as the software platform. This paper presents the main flow process design of the control system. The test results show that the control system can run automatically and switch mutually under different modes, and the functions such as monitor and control over the environment parameters of the GLP laboratory are realized.
Design of Multi-Parameter Steerable Functions Using Cascade Basis Reduction
NASA Technical Reports Server (NTRS)
Teo, P.; Hel-Or, Y.; Null, Cynthia H. (Technical Monitor)
1996-01-01
A new cascade basis reduction method of computing the optimal least-squares set of basis functions steering a given function is presented. The method combines the Lie group-theoretic and the singular value decomposition approaches in such a way that their respective strengths complement each other. Since the Lie group-theoretic approach is used, the set of basis and steering functions computed can be expressed analytically. Because the singular value decomposition method is used, this set of basis and steering functions is optimal in the least-squares sense. Furthermore, the computational complexity in designing basis functions for transformation groups with large numbers of parameters is significantly reduced. The efficiency of the cascade basis reduction method is demonstrated by designing a set of basis functions that steers a Gabor function under the four-parameter linear transformation group.
Classical Control System Design: A non-Graphical Method for Finding the Exact System Parameters
NASA Astrophysics Data System (ADS)
Hussein, Mohammed Tawfik
2008-06-01
The Root Locus method of control system design was developed in the 1940's. It is a set of rules that helps in sketching the path traced by the roots of the closed loop characteristic equation of the system, as a parameter such as a controller gain, k, is varied. The procedure provides approximate sketching guidelines. Designs on control systems using the method are therefore not exact. This paper aims at a non-graphical method for finding the exact system parameters to place a pair of complex conjugate poles on a specified damping ratio line. The overall procedure is based on the exact solution of complex equations on the PC using numerical methods.
NASA Technical Reports Server (NTRS)
Dermanis, A.
1977-01-01
The possibility of recovering earth rotation and network geometry (baseline) parameters are emphasized. The numerical simulated experiments performed are set up in an environment where station coordinates vary with respect to inertial space according to a simulated earth rotation model similar to the actual but unknown rotation of the earth. The basic technique of VLBI and its mathematical model are presented. The parametrization of earth rotation chosen is described and the resulting model is linearized. A simple analysis of the geometry of the observations leads to some useful hints on achieving maximum sensitivity of the observations with respect to the parameters considered. The basic philosophy for the simulation of data and their analysis through standard least squares adjustment techniques is presented. A number of characteristic network designs based on present and candidate station locations are chosen. The results of the simulations for each design are presented together with a summary of the conclusions.
Selection of parameters in the design of a naval fire control radar
NASA Astrophysics Data System (ADS)
As, Bengt-Olof; Tilfors, Einar
The rationale and tradeoff considerations involved in the definition of a new generation of high-performance tracking radar are described. The radar is the primary sensor for control of surface-to-air missiles, antiaircraft or dual-purpose guns, and close-in weapons, and is designed for all sizes of ships from 150 tons up. Operational requirements are outlined broadly and optimization investigations accounted for on a number of parameters: wavelengths, type of transmitter and waveforms, pulse compression principle, receiver and signal processing, and antenna. Data for the completed standard design are given.
Zhang, Ke; Jiang, Bin; Shi, Peng
2017-02-01
In this paper, a novel adjustable parameter (AP)-based distributed fault estimation observer (DFEO) is proposed for multiagent systems (MASs) with the directed communication topology. First, a relative output estimation error is defined based on the communication topology of MASs. Then a DFEO with AP is constructed with the purpose of improving the accuracy of fault estimation. Based on H ∞ and H 2 with pole placement, multiconstrained design is given to calculate the gain of DFEO. Finally, simulation results are presented to illustrate the feasibility and effectiveness of the proposed DFEO design with AP.
Developing the Parameters of Scholarship in Postgraduate Coursework Studies
ERIC Educational Resources Information Center
McLay, Allan F.
2013-01-01
Scholarship parameters, in relation to postgraduate coursework studies, are developed against the expectations of the Boyer classifications of scholarship (Boyer, 1990) with particular emphasis on the role of minor thesis development. An example is presented in which postgraduate coursework students are required to undertake a three semester minor…
Weeden, George S; Wang, Nien-Hwa Linda
2015-10-30
Size-exclusion simulated moving beds (SEC-SMB) have been used for large-scale separations of linear alkanes from branched alkanes. While SEC-SMBs are orders of magnitude more efficient than batch chromatography, they are not widely used. One key barrier is the complexity in design and optimization. A four-zone SEC-SMB for a binary separation has seven material properties and 14 design parameters (two yields, five operating parameters, and seven equipment parameters). Previous optimization studies using numerical methods do not guarantee global optima or explicitly express solvent consumption (D/F) or sorbent productivity (PR) as functions of the material properties and design parameters. The standing wave concept is used to develop analytical expressions for D/F and PR as functions of 14 dimensionless groups, which consist of 21 material and design parameters. The resulting speedy standing wave design (SSWD) solutions are simplified for two limiting cases: diffusion or dispersion controlled. An example of SEC-SMB for insulin purification is used to illustrate how D/F and PR change with the dimensionless groups. The results show that maximum PR for both diffusion and dispersion controlled systems is mainly determined by yields, equipment parameters, material properties, and two key dimensionless groups: (1) the ratio of step time to diffusion time and (2) the ratio of diffusion time to pressure-limited convection time. A sharp trade off of D/F and PR occurs when the yield is greater than 99%. The column configuration for maximum PR is analytically related to the diffusivity ratio and the selectivity. To achieve maximum sorbent productivity, one should match step time, diffusion time, and pressure-limited convection time for diffusion controlled systems. For dispersion controlled systems, the axial dispersion time should be about 10 times the step time and about 50 times the pressure-limited convection time. Its value can be estimated from given yields, material
Final Design and Performance Parameters of the Payloads PYREX, PHLUX and RESPECT on EXPERT
NASA Astrophysics Data System (ADS)
Lein, Sebastian; Steinbeck, Andreas; Preci, Arianit; Fertig, Markus; Herdrich, Georg; Röser, Hans-Peter; Auweter-Kurtz, Monika
An overview of the IRS payload development for ESA's EXPERT mission is given. The final design and performance parameters of the payloads PYREX, PHLUX and RESPECT are described. PYREX is a sensor system measuring the thermal protection system (TPS) rear side temperature. PHLUX is a catalysis based experiment to determine the dissociation degree of the boundary layer. RESPECT applies optical emission spectroscopy to measure spectrally resolved the radiation onto a TPS surface.
Parametric estimation of R&M parameters during the conceptual design of space vehicles
NASA Technical Reports Server (NTRS)
Ebeling, Charles E.
1992-01-01
Reliability and maintainability parameters of proposed space vehicles are estimated based on a comparability analysis of similar aircraft subsystems. Using multiple regression techniques, parametric equations are developed for each subsystem to predict mean flying hours between failure as a function of vehicle design and performance specifications. These estimates are then adjusted to account for reliability growth, environmental differences, and new technologies. Overall vehicle mission reliability may then be computed from subsystem reliability estimates.
Optimum Design of Forging Process Parameters and Preform Shape under Uncertainties
NASA Astrophysics Data System (ADS)
Repalle, Jalaja; Grandhi, Ramana V.
2004-06-01
Forging is a highly complex non-linear process that is vulnerable to various uncertainties, such as variations in billet geometry, die temperature, material properties, workpiece and forging equipment positional errors and process parameters. A combination of these uncertainties could induce heavy manufacturing losses through premature die failure, final part geometric distortion and production risk. Identifying the sources of uncertainties, quantifying and controlling them will reduce risk in the manufacturing environment, which will minimize the overall cost of production. In this paper, various uncertainties that affect forging tool life and preform design are identified, and their cumulative effect on the forging process is evaluated. Since the forging process simulation is computationally intensive, the response surface approach is used to reduce time by establishing a relationship between the system performance and the critical process design parameters. Variability in system performance due to randomness in the parameters is computed by applying Monte Carlo Simulations (MCS) on generated Response Surface Models (RSM). Finally, a Robust Methodology is developed to optimize forging process parameters and preform shape. The developed method is demonstrated by applying it to an axisymmetric H-cross section disk forging to improve the product quality and robustness.
NASA Astrophysics Data System (ADS)
Rob, Raluca; Rat, Cezara
2013-10-01
This paper presents a study concerning the variation of the most important electrical parameters, measured during the functioning of an electrothermal installation with electromagnetic induction. Two measuring methods are described: the first method consists in using a power and energy quality analyzer and the second uses a data acquisition system that contains an adapting interface and a data acquisition board connected to a computer. In order to compute the electrical parameters, a LabVIEW application was designed. The data acquisition system is able to measure in real time the variation of the parameters and also to save the obtained information.
Orientational order parameter estimated from molecular polarizabilities - an optical study
NASA Astrophysics Data System (ADS)
Lalitha Kumari, J.; Datta Prasad, P. V.; Madhavi Latha, D.; Pisipati, V. G. K. M.
2012-01-01
An optical study of N-(p-n-alkyloxybenzylidene)-p-n-butyloxyanilines, nO.O4 compounds with the alkoxy chain number n = 1, 3, 6, 7, and 10 has been carried out by measuring the refractive indices using modified spectrometer and direct measurement of birefringence employing the Newton's rings method. Further, the molecular polarizability anisotropies are evaluated using Lippincott δ-function model, the molecular vibration method, Haller's extrapolation method, and scaling factor method. The molecular polarizabilities α e and α 0 are calculated using Vuk's isotropic and Neugebauer anisotropic local field models. The order parameter S is estimated by employing the molecular polarizability values determined from experimental refractive indices and density data and the polarizability anisotropy values. Further, the order parameter S is also obtained directly from the birefringence data. A comparison has been carried out among the order parameter obtained from different ways and the results are compared with the body of the data available in the literature.
NASA Astrophysics Data System (ADS)
Jia, Zhiwei; Yan, Guozheng; Zhu, Bingquan
2015-04-01
An implanted telemetry system for experimental animals with or without anaesthesia can be used to continuously monitor physiological parameters. This system is significant not only in the study of organisms but also in the evaluation of drug efficacy, artificial organs, and auxiliary devices. The system is composed of a miniature electronic capsule, a wireless power transmission module, a data-recording device, and a processing module. An electrocardiograph, a temperature sensor, and a pressure sensor are integrated in the miniature electronic capsule, in which the signals are transmitted in vitro by wireless communication after filtering, amplification, and A/D sampling. To overcome the power shortage of batteries, a wireless power transmission module based on electromagnetic induction was designed. The transmitting coil of a rectangular-section solenoid and a 3D receiving coil are proposed according to stability and safety constraints. Experiments show that at least 150 mW of power could pick up on the load in a volume of Φ10.5 mm × 11 mm, with a transmission efficiency of 2.56%. Vivisection experiments verified the feasibility of the integrated radio-telemetry system.
Jia, Zhiwei; Yan, Guozheng; Zhu, Bingquan
2015-04-15
An implanted telemetry system for experimental animals with or without anaesthesia can be used to continuously monitor physiological parameters. This system is significant not only in the study of organisms but also in the evaluation of drug efficacy, artificial organs, and auxiliary devices. The system is composed of a miniature electronic capsule, a wireless power transmission module, a data-recording device, and a processing module. An electrocardiograph, a temperature sensor, and a pressure sensor are integrated in the miniature electronic capsule, in which the signals are transmitted in vitro by wireless communication after filtering, amplification, and A/D sampling. To overcome the power shortage of batteries, a wireless power transmission module based on electromagnetic induction was designed. The transmitting coil of a rectangular-section solenoid and a 3D receiving coil are proposed according to stability and safety constraints. Experiments show that at least 150 mW of power could pick up on the load in a volume of Φ10.5 mm × 11 mm, with a transmission efficiency of 2.56%. Vivisection experiments verified the feasibility of the integrated radio-telemetry system.
STUDY CARRELS, DESIGNS FOR INDEPENDENT STUDY SPACE.
ERIC Educational Resources Information Center
BEYNON, JOHN
BECAUSE OF THE DEMAND FOR INDIVIDUALIZED INSTRUCTION, NEW SCHOOLS ARE BEING PLANNED WITH LESS CLASSROOM SPACE AND MORE LIBRARY AND INDIVIDUAL STUDY SPACES. THESE NEW SCHOOLS REQUIRE NEW KINDS OF FURNITURE DESIGNED PRIMARILY TO GIVE THE STUDENT A DEGREE OF PRIVACY RATHER THAN TO PROVIDE OPTIMUM CONTROL TO TEACHERS. THE CARREL, PREVIOUSLY USED…
STUDY CARRELS, DESIGNS FOR INDEPENDENT STUDY SPACE.
ERIC Educational Resources Information Center
BEYNON, JOHN
BECAUSE OF THE DEMAND FOR INDIVIDUALIZED INSTRUCTION, NEW SCHOOLS ARE BEING PLANNED WITH LESS CLASSROOM SPACE AND MORE LIBRARY AND INDIVIDUAL STUDY SPACES. THESE NEW SCHOOLS REQUIRE NEW KINDS OF FURNITURE DESIGNED PRIMARILY TO GIVE THE STUDENT A DEGREE OF PRIVACY RATHER THAN TO PROVIDE OPTIMUM CONTROL TO TEACHERS. THE CARREL, PREVIOUSLY USED…
Optimal Parameter Design of Coarse Alignment for Fiber Optic Gyro Inertial Navigation System.
Lu, Baofeng; Wang, Qiuying; Yu, Chunmei; Gao, Wei
2015-06-25
Two different coarse alignment algorithms for Fiber Optic Gyro (FOG) Inertial Navigation System (INS) based on inertial reference frame are discussed in this paper. Both of them are based on gravity vector integration, therefore, the performance of these algorithms is determined by integration time. In previous works, integration time is selected by experience. In order to give a criterion for the selection process, and make the selection of the integration time more accurate, optimal parameter design of these algorithms for FOG INS is performed in this paper. The design process is accomplished based on the analysis of the error characteristics of these two coarse alignment algorithms. Moreover, this analysis and optimal parameter design allow us to make an adequate selection of the most accurate algorithm for FOG INS according to the actual operational conditions. The analysis and simulation results show that the parameter provided by this work is the optimal value, and indicate that in different operational conditions, the coarse alignment algorithms adopted for FOG INS are different in order to achieve better performance. Lastly, the experiment results validate the effectiveness of the proposed algorithm.
Chen, Yi; Huang, Weina; Peng, Bei
2014-01-01
Because of the demands for sustainable and renewable energy, fuel cells have become increasingly popular, particularly the polymer electrolyte fuel cell (PEFC). Among the various components, the cathode plays a key role in the operation of a PEFC. In this study, a quantitative dual-layer cathode model was proposed for determining the optimal parameters that minimize the over-potential difference and improve the efficiency using a newly developed bat swarm algorithm with a variable population embedded in the computational intelligence-aided design. The simulation results were in agreement with previously reported results, suggesting that the proposed technique has potential applications for automating and optimizing the design of PEFCs. PMID:25490761
Chen, Yi; Huang, Weina; Peng, Bei
2014-01-01
Because of the demands for sustainable and renewable energy, fuel cells have become increasingly popular, particularly the polymer electrolyte fuel cell (PEFC). Among the various components, the cathode plays a key role in the operation of a PEFC. In this study, a quantitative dual-layer cathode model was proposed for determining the optimal parameters that minimize the over-potential difference η and improve the efficiency using a newly developed bat swarm algorithm with a variable population embedded in the computational intelligence-aided design. The simulation results were in agreement with previously reported results, suggesting that the proposed technique has potential applications for automating and optimizing the design of PEFCs.
Flavonoid-DNA binding studies and thermodynamic parameters
NASA Astrophysics Data System (ADS)
Janjua, Naveed Kausar; Shaheen, Amber; Yaqub, Azra; Perveen, Fouzia; Sabahat, Sana; Mumtaz, Misbah; Jacob, Claus; Ba, Lalla Aicha; Mohammed, Hamdoon A.
2011-09-01
Interactional studies of new flavonoid derivatives (Fl) with chicken blood ds.DNA were investigated spectrophotometrically in DMSO-H 2O (9:1 v/v) at various temperatures. Spectral parameters suggest considerable binding between the flavonoid derivatives studied and ds.DNA. The binding constant values lie in the enhanced-binding range. Thermodynamic parameters obtained from UV studies also point to strong spontaneous binding of Fl with ds.DNA. Viscometric studies complimented the UV results where a small linear increase in relative viscosity of the DNA solution was observed with added optimal flavonoid concentration. An overall mixed mode of interaction (intercalative plus groove binding) is proposed between DNA and flavonoids. Conclusively, investigated flavonoid derivatives are found to be strong DNA binders and seem to be promising drug candidates like their natural analogues.
Parameter trade-off studies for the ultra-high flux double donut reactor
Ryskamp, J.M.; Oh, C.H.; Ambrosek, R.G.; Lussie, W.G.; Lake, J.A.; Wadkins, R.P.
1987-01-01
The Idaho National Engineering Laboratory (INEL) is developing a reactor design in a double donut configuration for the advanced neutron source (ANS). The ANS, with a neutron flux ten times that of existing sources, is needed for materials science, isotope production, and fundamental physics research. The purpose of this study is to examine the reactor parameters for the INEL Ultrahigh Flux Reactor (UHFR) and recommend ways to optimize the reactor design.
Parameter trade-off studies for the ultrahigh flux double donut reactor
Ryskamp, J.M.; Oh, C.H.; Ambrosek, R.G.; Lussie, W.G.; Lake, J.A.; Wadkins, R.P.
1987-01-01
The Idaho National Engineering Laboratory (INEL) is developing a reactor design in a double donut configuration for the advanced neutron source (ANS). The ANS, with a neutron flux ten times that of existing sources, is needed for materials science, isotope production, and fundamental physics research. The purpose of this study is to examine the reactor parameters for the INEL Ultrahigh Flux Reactor (UHFR) and recommend ways to optimize the reactor design.
NASA Technical Reports Server (NTRS)
Moorhead, S. B., Jr.
1973-01-01
A warm gas thrust vector control system was studied to optimize the injection geometry for a specific engine configuration, and an injection valve was designed capable of meeting the base line requirements. To optimize injection geometry, studies were made to determine the performance effects of varying injection location, angle, port size, and port configuration. Having minimized the injection flow rate required, a warm gas valve was designed to handle the required flow. A direct drive hydraulic servovalve capable of operating with highly contaminated hydraulic fluid was designed. The valve is sized to flow 15 gpm at 3000 psia and the direct drive feature is capable of applying a spool force of 200 pounds. The baseline requirements are the development of 6 deg of thrust vector control utilizing 2000 F (total temperature) gas for 180 seconds on a 1.37 million pound thrust engine burning LOX and RP-1 at a chamber pressure of 250 psia with a 155 inch long conical nozzle having a 68 inch diameter throat and a 153 inch diameter exit.
Supersonic airplane study and design
NASA Technical Reports Server (NTRS)
Cheung, Samson
1993-01-01
A supersonic airplane creates shocks which coalesce and form a classical N-wave on the ground, forming a double bang noise termed sonic boom. A recent supersonic commercial transport (the Concorde) has a loud sonic boom (over 100 PLdB) and low aerodynamic performance (cruise lift-drag ratio 7). To enhance the U.S. market share in supersonic transport, an airframer's market risk for a low-boom airplane has to be reduced. Computational fluid dynamics (CFD) is used to design airplanes to meet the dual constraints of low sonic boom and high aerodynamic performance. During the past year, a research effort was focused on three main topics. The first was to use the existing design tools, developed in past years, to design one of the low-boom wind-tunnel configurations (Ames Model 3) for testing at Ames Research Center in April 1993. The second was to use a Navier-Stokes code (Overflow) to support the Oblique-All-Wing (OAW) study at Ames. The third was to study an optimization technique applied on a Haack-Adams body to reduce aerodynamic drag.
Thermodynamic Studies for Drug Design and Screening
Garbett, Nichola C.; Chaires, Jonathan B.
2012-01-01
Introduction A key part of drug design and development is the optimization of molecular interactions between an engineered drug candidate and its binding target. Thermodynamic characterization provides information about the balance of energetic forces driving binding interactions and is essential for understanding and optimizing molecular interactions. Areas covered This review discusses the information that can be obtained from thermodynamic measurements and how this can be applied to the drug development process. Current approaches for the measurement and optimization of thermodynamic parameters are presented, specifically higher throughput and calorimetric methods. Relevant literature for this review was identified in part by bibliographic searches for the period 2004 – 2011 using the Science Citation Index and PUBMED and the keywords listed below. Expert opinion The most effective drug design and development platform comes from an integrated process utilizing all available information from structural, thermodynamic and biological studies. Continuing evolution in our understanding of the energetic basis of molecular interactions and advances in thermodynamic methods for widespread application are essential to realize the goal of thermodynamically-driven drug design. Comprehensive thermodynamic evaluation is vital early in the drug development process to speed drug development towards an optimal energetic interaction profile while retaining good pharmacological properties. Practical thermodynamic approaches, such as enthalpic optimization, thermodynamic optimization plots and the enthalpic efficiency index, have now matured to provide proven utility in design process. Improved throughput in calorimetric methods remains essential for even greater integration of thermodynamics into drug design. PMID:22458502
Central suboptimal H ∞ controller design for linear time-varying systems with unknown parameters
NASA Astrophysics Data System (ADS)
Basin, Michael V.; Soto, Pedro; Calderon-Alvarez, Dario
2011-05-01
This article presents the central finite-dimensional H ∞ controller for linear time-varying systems with unknown parameters, that is suboptimal for a given threshold γ with respect to a modified Bolza-Meyer quadratic criterion including the attenuation control term with the opposite sign. In contrast to the previously obtained results, this article reduces the original H ∞ controller problem to the corresponding H 2 controller problem, using the technique proposed in Doyle et al. [Doyle, J.C., Glover, K., Khargonekar, P.P., and Francis, B.A. (1989), 'State-space Solutions to Standard H 2 and H Infinity Control Problems', IEEE Transactions Automatic Control, 34, 831-847]. This article yields the central suboptimal H ∞ controller for linear systems with unknown parameters in a closed finite-dimensional form, based on the corresponding H 2 controller obtained in Basin and Calderon-Alvarez [Basin, M.V., and Calderon-Alvarez, D. (2008), 'Optimal LQG Controller for Linear Systems with Unknown Parameters', Journal of The Franklin Institute, 345, 293-302]. Numerical simulations are conducted to verify performance of the designed central suboptimal controller for uncertain linear systems with unknown parameters against the conventional central suboptimal H ∞ controller for linear systems with exactly known parameter values.
USAF Advanced Terrestrial Energy Study. Volume 3. Parameter Survey.
1983-04-01
source for each system. Primary fuels for the purpose of this study include- - JP-4 - Diesel (DF-l or DF-2) - Electricity - Natural gas - Solar - Wind...for the gas turbines, diesel engines, Stirling engines, fuel cells, photovoltaics, and wind turbines. All systems were evaluated on the basis of...R1-A33 581 USAF ADVANCED TERRESTRIAL ENERGY STUDY VOLUME 3 i/i PARAMETER SURVEY(U) INSTITUTE OF GAS TECHNOLOGY CHICAGO ILL E J DANIELS ET AL. APR 83
The Study of the Optimal Parameter Settings in a Hospital Supply Chain System in Taiwan
Liao, Hung-Chang; Chen, Meng-Hao; Wang, Ya-huei
2014-01-01
This study proposed the optimal parameter settings for the hospital supply chain system (HSCS) when either the total system cost (TSC) or patient safety level (PSL) (or both simultaneously) was considered as the measure of the HSCS's performance. Four parameters were considered in the HSCS: safety stock, maximum inventory level, transportation capacity, and the reliability of the HSCS. A full-factor experimental design was used to simulate an HSCS for the purpose of collecting data. The response surface method (RSM) was used to construct the regression model, and a genetic algorithm (GA) was applied to obtain the optimal parameter settings for the HSCS. The results show that the best method of obtaining the optimal parameter settings for the HSCS is the simultaneous consideration of both the TSC and the PSL to measure performance. Also, the results of sensitivity analysis based on the optimal parameter settings were used to derive adjustable strategies for the decision-makers. PMID:25250397
Some considerations on the design of population pharmacokinetic studies.
Duffull, Stephen; Waterhouse, Tim; Eccleston, John
2005-08-01
The goal of this manuscript is to introduce a framework for consideration of designs for population pharmacokinetic orpharmacokinetic-pharmacodynamic studies. A standard one compartment pharmacokinetic model with first-order input and elimination is considered. A series of theoretical designs are considered that explore the influence of optimizing the allocation of sampling times, allocating patients to elementary designs, consideration of sparse sampling and unbalanced designs and also the influence of single vs. multiple dose designs. It was found that what appears to be relatively sparse sampling (less blood samples per patient than the number of fixed effects parameters to estimate) can also be highly informative. Overall, it is evident that exploring the population design space can yield many parsimonious designs that are efficient for parameter estimation and that may not otherwise have been considered without the aid of optimal design theory.
He, L; Huang, G H; Lu, H W
2010-04-15
Solving groundwater remediation optimization problems based on proxy simulators can usually yield optimal solutions differing from the "true" ones of the problem. This study presents a new stochastic optimization model under modeling uncertainty and parameter certainty (SOMUM) and the associated solution method for simultaneously addressing modeling uncertainty associated with simulator residuals and optimizing groundwater remediation processes. This is a new attempt different from the previous modeling efforts. The previous ones focused on addressing uncertainty in physical parameters (i.e. soil porosity) while this one aims to deal with uncertainty in mathematical simulator (arising from model residuals). Compared to the existing modeling approaches (i.e. only parameter uncertainty is considered), the model has the advantages of providing mean-variance analysis for contaminant concentrations, mitigating the effects of modeling uncertainties on optimal remediation strategies, offering confidence level of optimal remediation strategies to system designers, and reducing computational cost in optimization processes.
Correlation of Clinicohaematological Parameters in Paediatric Dengue: A Retrospective Study
Pai Jakribettu, Ramakrishna; Boloor, Rekha; Thaliath, Andrew; Yesudasan George, Sharanya; George, Thomas; Ponadka Rai, Manoj; Rafique Sheikh, Umran; Avabratha, Kadke Shreedhara; Baliga, Manjeshwar Shrinath
2015-01-01
Dengue is one of the arthropod-borne (arbo) viral diseases transmitted by female mosquito Aedes aegypti. Dengue fever has a wide spectrum of clinical presentation ranging from flu-like illness to severe complicated stage of dengue hemorrhagic fever leading to mortality. This was a retrospective study conducted in a tertiary care hospital in Coastal Karnataka, South India, to know the correlation between the clinical presentation and haematological parameters in the paediatric cases presented with dengue symptoms. A total of 163 paediatric cases who presented fever and dengue-like illness were included in the study. Of which, 69 were confirmed dengue patients. Critical analysis showed that there was a significant difference in the haematological parameters like total leucocyte count, percent differential leucocyte count, and platelets count, in the erythrocyte sedimentation rate (P < 0.05 to 0.0001). Additionally, when compared to nondengue patients, even the liver function and renal function parameters were significantly deranged (P < 0.05 to 0.0001). Stratification based on NS1, IgG, and IgM showed significant alterations in the haematological, hepatic, and renal parameters. With respect to the treatment a small percentage of patients, that is, 8% (4 patients), required platelet transfusion as their counts went below 20,000/μL. Two patients succumbed to their illness while three required ICU stay. PMID:26819620
Sensitivity analysis of a dry-processed Candu fuel pellet's design parameters
Choi, Hangbok; Ryu, Ho Jin
2007-07-01
Sensitivity analysis was carried out in order to investigate the effect of a fuel pellet's design parameters on the performance of a dry-processed Canada deuterium uranium (CANDU) fuel and to suggest the optimum design modifications. Under a normal operating condition, a dry-processed fuel has a higher internal pressure and plastic strain due to a higher fuel centerline temperature when compared with a standard natural uranium CANDU fuel. Under a condition that the fuel bundle dimensions do not change, sensitivity calculations were performed on a fuel's design parameters such as the axial gap, dish depth, gap clearance and plenum volume. The results showed that the internal pressure and plastic strain of the cladding were most effectively reduced if a fuel's element plenum volume was increased. More specifically, the internal pressure and plastic strain of the dry-processed fuel satisfied the design limits of a standard CANDU fuel when the plenum volume was increased by one half a pellet, 0.5 mm{sup 3}/K. (authors)
Design Evolution Study - Aging Options
P. McDaniel
2002-04-05
The purpose of this study is to identify options and issues for aging commercial spent nuclear fuel received for disposal at the Yucca Mountain Mined Geologic Repository. Some early shipments of commercial spent nuclear fuel to the repository may be received with high-heat-output (younger) fuel assemblies that will need to be managed to meet thermal goals for emplacement. The capability to age as much as 40,000 metric tons of heavy metal of commercial spent nuclear he1 would provide more flexibility in the design to manage this younger fuel and to decouple waste receipt and waste emplacement. The following potential aging location options are evaluated: (1) Surface aging at four locations near the North Portal; (2) Subsurface aging in the permanent emplacement drifts; and (3) Subsurface aging in a new subsurface area. The following aging container options are evaluated: (1) Complete Waste Package; (2) Stainless Steel inner liner of the waste package; (3) Dual Purpose Canisters; (4) Multi-Purpose Canisters; and (5) New disposable canister for uncanistered commercial spent nuclear fuel. Each option is compared to a ''Base Case,'' which is the expected normal waste packaging process without aging. A Value Engineering approach is used to score each option against nine technical criteria and rank the options. Open issues with each of the options and suggested future actions are also presented. Costs for aging containers and aging locations are evaluated separately. Capital costs are developed for direct costs and distributable field costs. To the extent practical, unit costs are presented. Indirect costs, operating costs, and total system life cycle costs will be evaluated outside of this study. Three recommendations for aging commercial spent nuclear fuel--subsurface, surface, and combined surface and subsurface are presented for further review in the overall design re-evaluation effort. Options that were evaluated but not recommended are: subsurface aging in a new
ERIC Educational Resources Information Center
Li, Yuan H.; Griffith, William D.; Tam, Hak P.
This study explores the relative merits of a potentially useful item response theory (IRT) linking design: using a single set of anchor items with fixed common item parameters (FCIP) during the calibration process. An empirical study was conducted to investigate the appropriateness of this linking design using 6 groups of students taking 6 forms…
Guidelines for the Selection of Near-Earth Thermal Environment Parameters for Spacecraft Design
NASA Technical Reports Server (NTRS)
Anderson, B. J.; Justus, C. G.; Batts, G. W.
2001-01-01
Thermal analysis and design of Earth orbiting systems requires specification of three environmental thermal parameters: the direct solar irradiance, Earth's local albedo, and outgoing longwave radiance (OLR). In the early 1990s data sets from the Earth Radiation Budget Experiment were analyzed on behalf of the Space Station Program to provide an accurate description of these parameters as a function of averaging time along the orbital path. This information, documented in SSP 30425 and, in more generic form in NASA/TM-4527, enabled the specification of the proper thermal parameters for systems of various thermal response time constants. However, working with the engineering community and SSP-30425 and TM-4527 products over a number of years revealed difficulties in interpretation and application of this material. For this reason it was decided to develop this guidelines document to help resolve these issues of practical application. In the process, the data were extensively reprocessed and a new computer code, the Simple Thermal Environment Model (STEM) was developed to simplify the process of selecting the parameters for input into extreme hot and cold thermal analyses and design specifications. In the process, greatly improved values for the cold case OLR values for high inclination orbits were derived. Thermal parameters for satellites in low, medium, and high inclination low-Earth orbit and with various system thermal time constraints are recommended for analysis of extreme hot and cold conditions. Practical information as to the interpretation and application of the information and an introduction to the STEM are included. Complete documentation for STEM is found in the user's manual, in preparation.
Godfraind, Carmen; Debelle, Adrien; Lonys, Laurent; Acuña, Vicente; Doguet, Pascal; Nonclercq, Antoine
2016-01-01
Inductive powering of implantable medical devices involves numerous factors acting on the system efficiency and safety in adversarial ways. This paper lightens up their role and identifies a procedure enabling the system design. The latter enables the problem to be decoupled into four principal steps: the frequency choice, the magnetic link optimization, the secondary circuit and then finally the primary circuit designs. The methodology has been tested for the powering system of a device requirering a power of 300mW and implanted at a distance of 15 to 30mm from the outside power source. It allowed the identification of the most critical parameters. A satisfying efficiency of 34% was reached at 21mm and tend to validate the proposed design procedure. PMID:27478572
Godfraind, Carmen; Debelle, Adrien; Lonys, Laurent; Acuña, Vicente; Doguet, Pascal; Nonclercq, Antoine
2016-06-13
Inductive powering of implantable medical devices involves numerous factors acting on the system efficiency and safety in adversarial ways. This paper lightens up their role and identifies a procedure enabling the system design. The latter enables the problem to be decoupled into four principal steps: the frequency choice, the magnetic link optimization, the secondary circuit and then finally the primary circuit designs. The methodology has been tested for the powering system of a device requirering a power of 300mW and implanted at a distance of 15 to 30mm from the outside power source. It allowed the identification of the most critical parameters. A satisfying efficiency of 34% was reached at 21mm and tend to validate the proposed design procedure.
NASA Technical Reports Server (NTRS)
Seidel, R. C.; Lehtinen, B.
1974-01-01
A technique is described for designing feedback control systems using frequency domain models, a quadratic cost function, and a parameter optimization computer program. FORTRAN listings for the computer program are included. The approach is applied to the design of shock position controllers for a supersonic inlet. Deterministic or random system disturbances, and the presence of random measurement noise are considered. The cost function minimization is formulated in the time domain, but the problem solution is obtained using a frequency domain system description. A scaled and constrained conjugate gradient algorithm is used for the minimization. The approach to a supersonic inlet included the calculations of the optimal proportional-plus integral (PI) and proportional-plus-integral-plus-derivative controllers. A single-loop PI controller was the most desirable of the designs considered.
The proton driver design study
Editors: W. Chou, C.M. Ankenbrandt and E.I. Malamud
2001-03-08
In a 1997 summer study, a team led by Steve Holmes formulated a development plan for the Fermilab proton source and described the results in TM-2021. Subsequently, at the end of 1998, a task group was formed to prepare a detailed design of a high intensity facility called the Proton Driver to replace the Fermilab Booster. In the past two years the design effort has attracted more than fifty participants, mostly from the Beams Division. Physicists and engineers from the Technical Division and FESS as well as other institutions, including the Illinois Institute of Technology (IIT), Stanford University, University of Hawaii, CERN in Switzerland, Rutherford Appleton Laboratory in England and the IHEP in Russia also contributed heavily. The results of that effort are summarized in this document describing the design of a 16 GeV synchrotron, two new beam transport lines (a 400 MeV injection line and a 12/16 GeV extraction line), and related improvements to the present negative ion source and the 400 MeV Linac. A construction cost estimate is presented in Appendix A.
Mian, Muhammad Umer Khir, M. H. Md.; Tang, T. B.; Dennis, John Ojur; Riaz, Kashif; Iqbal, Abid; Bazaz, Shafaat A.
2015-07-22
Pre-fabrication, behavioural and performance analysis with computer aided design (CAD) tools is a common and fabrication cost effective practice. In light of this we present a simulation methodology for a dual-mass oscillator based 3 Degree of Freedom (3-DoF) MEMS gyroscope. 3-DoF Gyroscope is modeled through lumped parameter models using equivalent circuit elements. These equivalent circuits consist of elementary components which are counterpart of their respective mechanical components, used to design and fabricate 3-DoF MEMS gyroscope. Complete designing of equivalent circuit model, mathematical modeling and simulation are being presented in this paper. Behaviors of the equivalent lumped models derived for the proposed device design are simulated in MEMSPRO T-SPICE software. Simulations are carried out with the design specifications following design rules of the MetalMUMPS fabrication process. Drive mass resonant frequencies simulated by this technique are 1.59 kHz and 2.05 kHz respectively, which are close to the resonant frequencies found by the analytical formulation of the gyroscope. The lumped equivalent circuit modeling technique proved to be a time efficient modeling technique for the analysis of complex MEMS devices like 3-DoF gyroscopes. The technique proves to be an alternative approach to the complex and time consuming couple field analysis Finite Element Analysis (FEA) previously used.
NASA Astrophysics Data System (ADS)
Mian, Muhammad Umer; Dennis, John Ojur; Khir, M. H. Md.; Riaz, Kashif; Iqbal, Abid; Bazaz, Shafaat A.; Tang, T. B.
2015-07-01
Pre-fabrication, behavioural and performance analysis with computer aided design (CAD) tools is a common and fabrication cost effective practice. In light of this we present a simulation methodology for a dual-mass oscillator based 3 Degree of Freedom (3-DoF) MEMS gyroscope. 3-DoF Gyroscope is modeled through lumped parameter models using equivalent circuit elements. These equivalent circuits consist of elementary components which are counterpart of their respective mechanical components, used to design and fabricate 3-DoF MEMS gyroscope. Complete designing of equivalent circuit model, mathematical modeling and simulation are being presented in this paper. Behaviors of the equivalent lumped models derived for the proposed device design are simulated in MEMSPRO T-SPICE software. Simulations are carried out with the design specifications following design rules of the MetalMUMPS fabrication process. Drive mass resonant frequencies simulated by this technique are 1.59 kHz and 2.05 kHz respectively, which are close to the resonant frequencies found by the analytical formulation of the gyroscope. The lumped equivalent circuit modeling technique proved to be a time efficient modeling technique for the analysis of complex MEMS devices like 3-DoF gyroscopes. The technique proves to be an alternative approach to the complex and time consuming couple field analysis Finite Element Analysis (FEA) previously used.
Design Issues in Transgender Studies
Emel, Lynda; Hanscom, Brett; Zangeneh, Sahar
2016-01-01
Abstract: Transgender individuals constitute an important focus for HIV prevention, but studies in this population present some unique methodologic and operational challenges. We consider issues related to sampling, sample size, number of sites, and trial cost. We discuss relevant design issues for evaluating interventions in both HIV-negative and HIV-infected transgender populations, as well as a method for assessing the impact of an intervention on population HIV incidence. We find that HIV-endpoint studies of transgender individuals will likely require fewer participants but more sites and have higher operational costs than HIV prevention trials in other populations. Because any intervention targeted to transgender individuals will likely include antiretroviral drugs, small scale studies looking at potential interactions between antiretroviral therapy and hormone therapy are recommended. Finally, assessing the impact of an intervention targeted to transgender individuals will require better information on the contribution of such individuals to the population HIV incidence. PMID:27429191
Design Issues in Transgender Studies.
Hughes, James P; Emel, Lynda; Hanscom, Brett; Zangeneh, Sahar
2016-08-15
Transgender individuals constitute an important focus for HIV prevention, but studies in this population present some unique methodologic and operational challenges. We consider issues related to sampling, sample size, number of sites, and trial cost. We discuss relevant design issues for evaluating interventions in both HIV-negative and HIV-infected transgender populations, as well as a method for assessing the impact of an intervention on population HIV incidence. We find that HIV-endpoint studies of transgender individuals will likely require fewer participants but more sites and have higher operational costs than HIV prevention trials in other populations. Because any intervention targeted to transgender individuals will likely include antiretroviral drugs, small scale studies looking at potential interactions between antiretroviral therapy and hormone therapy are recommended. Finally, assessing the impact of an intervention targeted to transgender individuals will require better information on the contribution of such individuals to the population HIV incidence.
Design study for a magnetically supported reaction wheel
NASA Technical Reports Server (NTRS)
Stocking, G.; Dendy, J.; Sabnis, A.
1974-01-01
Results are described of a study program in which the characteristics of a magnetically supported reaction wheel are defined. Tradeoff analyses are presented for the principal components, which are then combined in several reaction wheel design concepts. A preliminary layout of the preferred configuration is presented along with calculated design and performance parameters. Recommendations are made for a prototype development program.
Michaud, Mark; Leong, Thomas; Swiergon, Piotr; Juliano, Pablo; Knoerzer, Kai
2015-09-01
This work validated, in a higher frequency range, the theoretical predictions made by Boyle around 1930, which state that the optimal transmission of sound pressure through a metal plate occurs when the plate thickness equals a multiple of half the wavelength of the sound wave. Several reactor design parameters influencing the transmission of high frequency ultrasonic waves through a stainless steel plate were examined. The transmission properties of steel plates of various thicknesses (1-7 mm) were studied for frequencies ranging from 400 kHz to 2 MHz and at different distances between plates and transducers. It was shown that transmission of sound pressure through a steel plate showed high dependence of the thickness of the plate to the frequency of the sound wave (thickness ratio). Maximum sound pressure transmission of ∼ 60% of the incident pressure was observed when the ratio of the plate thickness to the applied frequency was a multiple of a half wavelength (2 MHz, 6mm stainless steel plate). In contrast, minimal sound pressure transmission (∼ 10-20%) was measured for thickness ratios that were not a multiple of a half wavelength. Furthermore, the attenuation of the sound pressure in the transmission region was also investigated. As expected, it was confirmed that higher frequencies have more pronounced sound pressure attenuation than lower frequencies. The spatial distribution of the sound pressure transmitted through the plate characterized by sonochemiluminescence measurements using luminol emission, supports the validity of the pressure measurements in this study. Copyright © 2015 Elsevier B.V. All rights reserved.
Parameters design of the dielectric elastomer spring-roll bending actuator (Conference Presentation)
NASA Astrophysics Data System (ADS)
Li, Jinrong; Liu, Liwu; Liu, Yanju; Leng, Jinsong
2017-04-01
Dielectric elastomers are novel soft smart material that could deform sustainably when subjected to external electric field. That makes dielectric elastomers promising materials for actuators. In this paper, a spring-roll actuator that would bend when a high voltage is applied was fabricated based on dielectric elastomer. Using such actuators as active parts, the flexible grippers and inchworm-inspired crawling robots were manufactured, which demonstrated some examples of applications in soft robotics. To guide the parameters design of dielectric elastomer based spring-roll bending actuators, the theoretical model of such actuators was established based on thermodynamic theories. The initial deformation and electrical induced bending angle of actuators were formulated. The failure of actuators was also analyzed considering some typical failure modes like electromechanical instability, electrical breakdown, loss of tension and maximum tolerant stretch. Thus the allowable region of actuators was determined. Then the bending angle-voltage relations and failure voltages of actuators with different parameters, including stretches of the dielectric elastomer film, number of active layers, and dimensions of spring, were investigated. The influences of each parameter on the actuator performances were discussed, providing meaningful guidance to the optical design of the spring-roll bending actuators.
Longhi, Daniel Angelo; Martins, Wiaslan Figueiredo; da Silva, Nathália Buss; Carciofi, Bruno Augusto Mattar; de Aragão, Gláucia Maria Falcão; Laurindo, João Borges
2017-01-02
In predictive microbiology, the model parameters have been estimated using the sequential two-step modeling (TSM) approach, in which primary models are fitted to the microbial growth data, and then secondary models are fitted to the primary model parameters to represent their dependence with the environmental variables (e.g., temperature). The Optimal Experimental Design (OED) approach allows reducing the experimental workload and costs, and the improvement of model identifiability because primary and secondary models are fitted simultaneously from non-isothermal data. Lactobacillus viridescens was selected to this study because it is a lactic acid bacterium of great interest to meat products preservation. The objectives of this study were to estimate the growth parameters of L. viridescens in culture medium from TSM and OED approaches and to evaluate both the number of experimental data and the time needed in each approach and the confidence intervals of the model parameters. Experimental data for estimating the model parameters with TSM approach were obtained at six temperatures (total experimental time of 3540h and 196 experimental data of microbial growth). Data for OED approach were obtained from four optimal non-isothermal profiles (total experimental time of 588h and 60 experimental data of microbial growth), two profiles with increasing temperatures (IT) and two with decreasing temperatures (DT). The Baranyi and Roberts primary model and the square root secondary model were used to describe the microbial growth, in which the parameters b and Tmin (±95% confidence interval) were estimated from the experimental data. The parameters obtained from TSM approach were b=0.0290 (±0.0020) [1/(h(0.5)°C)] and Tmin=-1.33 (±1.26) [°C], with R(2)=0.986 and RMSE=0.581, and the parameters obtained with the OED approach were b=0.0316 (±0.0013) [1/(h(0.5)°C)] and Tmin=-0.24 (±0.55) [°C], with R(2)=0.990 and RMSE=0.436. The parameters obtained from OED approach
Panić, Sanja; Rakić, Dušan; Guzsvány, Valéria; Kiss, Erne; Boskovic, Goran; Kónya, Zoltán; Kukovecz, Ákos
2015-12-01
The aim of this work was to evaluate significant factors affecting the thiamethoxam adsorption efficiency using oxidized multi-walled carbon nanotubes (MWCNTs) as adsorbents. Five factors (initial solution concentration of thiamethoxam in water, temperature, solution pH, MWCNTs weight and contact time) were investigated using 2V(5-1) fractional factorial design. The obtained linear model was statistically tested using analysis of variance (ANOVA) and the analysis of residuals was used to investigate the model validity. It was observed that the factors and their second-order interactions affecting the thiamethoxam removal can be divided into three groups: very important, moderately important and insignificant ones. The initial solution concentration was found to be the most influencing parameter on thiamethoxam adsorption from water. Optimization of the factors levels was carried out by minimizing those parameters which are usually critical in real life: the temperature (energy), contact time (money) and weight of MWCNTs (potential health hazard), in order to maximize the adsorbed amount of the pollutant. The results of maximal adsorbed thiamethoxam amount in both real and optimized experiments indicate that among minimized parameters the adsorption time is one that makes the largest difference. The results of this study indicate that fractional factorial design is very useful tool for screening the higher number of parameters and reducing the number of adsorption experiments.
Study of Correlationships between Main Ionospheric Parameters by Stochastic Modeling
NASA Astrophysics Data System (ADS)
Podolská, K.; Truhlík, V.; Třísková, L.
2012-04-01
We employ multivariate statistic methods applied to long period daily observational data for find out time shifts between fundamental ionospheric parameters. The F2 layer critical frequency (foF2), Kp index, and solar radiation flux at 10.7cm (F10.7 index), and relative sunspot number R as indicators of phase of solar cycle as studied time series was used. As a paralel observed series was utilized E10.7 (Solar EUV index based on F10.7) and TEC series. The foF2 data series measured from mid-latitude ionosonde stations was used. For investigation of relationships between time and geographic variations of parameters studied we employ the method of the conditional independence graphical models (CIG) which describing and transparently representing structure of dependence relationships in the time series. This method appears useful for studying the correlationships between fundamental ionospheric parameters and can be applied even in the case when classical parametric methods are not convenient, e.g. for non-continuous time series etc. We consider the structure of pairwise dependence of its individual components, looking for the maximum likelihood estimate of the variance matrix under conditions given by the graphical model. The CIG method allowed implementation of additional time series variables into previous model. Simultaneously we used clasical stochastic model. The data best fit relationship model is computed.
MIUS community conceptual design study
NASA Technical Reports Server (NTRS)
Fulbright, B. E.
1976-01-01
The feasibility, practicality, and applicability of the modular integrated utility systems (MIUS) concept to a satellite new-community development with a population of approximately 100,000 were analyzed. Two MIUS design options, the 29-MIUS-unit (option 1) and the 8-MIUS-unit (option 2) facilities were considered. Each resulted in considerable resource savings when compared to a conventional utility system. Economic analyses indicated that the total cash outlay and operations and maintenance costs for these two options were considerably less than for a conventional system. Computer analyses performed in support of this study provided corroborative data for the study group. An environmental impact assessment was performed to determine whether the MIUS meets or will meet necessary environmental standards. The MIUS can provide improved efficiency in the conservation of natural resources while not adversely affecting the physical environment.
Adams, Brian M.; Ebeida, Mohamed Salah; Eldred, Michael S.; Jakeman, John Davis; Swiler, Laura Painton; Stephens, John Adam; Vigil, Dena M.; Wildey, Timothy Michael; Bohnhoff, William J.; Eddy, John P.; Hu, Kenneth T.; Dalbey, Keith R.; Bauman, Lara E; Hough, Patricia Diane
2014-05-01
The Dakota (Design Analysis Kit for Optimization and Terascale Applications) toolkit provides a exible and extensible interface between simulation codes and iterative analysis methods. Dakota contains algorithms for optimization with gradient and nongradient-based methods; uncertainty quanti cation with sampling, reliability, and stochastic expansion methods; parameter estimation with nonlinear least squares methods; and sensitivity/variance analysis with design of experiments and parameter study methods. These capabilities may be used on their own or as components within advanced strategies such as surrogate-based optimization, mixed integer nonlinear programming, or optimization under uncertainty. By employing object-oriented design to implement abstractions of the key components required for iterative systems analyses, the Dakota toolkit provides a exible and extensible problem-solving environment for design and performance analysis of computational models on high performance computers. This report serves as a user's manual for the Dakota software and provides capability overviews and procedures for software execution, as well as a variety of example studies.
Linear parameter varying control design for rotating systems supported by journal bearings
NASA Astrophysics Data System (ADS)
Almeida Gonçalves Siqueira, Adriano; Nicoletti, Rodrigo; Norrick, Nicklas; Lucchesi Cavalca, Kátia; Fiori de Castro, Helio; Bauer, Jens; Dohnal, Fadi
2012-05-01
Linear parameter varying (LPV) control is a model-based control technique that takes into account time-varying parameters of the plant. In the case of rotating systems supported by lubricated bearings, the dynamic characteristics of the bearings change in time as a function of the rotating speed. Hence, LPV control can tackle the problem of run-up and run-down operational conditions when dynamic characteristics of the rotating system change significantly in time due to the bearings and high vibration levels occur. In this work, the LPV control design for a flexible shaft supported by plain journal bearings is presented. The model used in the LPV control design is updated from unbalance response experimental results and dynamic coefficients for the entire range of rotating speeds are obtained by numerical optimization. Experimental implementation of the designed LPV control resulted in strong reduction of vibration amplitudes when crossing the critical speed, without affecting system behavior in sub- or super-critical speeds.
Investigation of the design parameters of quantum dot enhanced III-V solar cells
NASA Astrophysics Data System (ADS)
Driscoll, Kristina; Bennett, Mitchell; Polly, Stephen; Forbes, David V.; Hubbard, Seth M.
2013-03-01
The incorporation of nanostructures, such as quantum dots (QD), into the intrinsic region of III-V solar cells has been proposed as a potential route towards boosting conversion efficiencies with immediate applications in concentrator photovoltaic and space power systems. Necessary to the optimization process of this particular class of solar cells is the ability to correlate nanoscale properties with macroscopic device characteristics. To this purpose, the physics-based software Crosslight APSYS has been developed to investigate the design parameters of QD enhanced solar cells with particular focus on the InAs/GaAs system. This methodology is used to study how nanoscale variables, including size, shape and material compositions, influence photovoltaic performance. In addition, device-level engineering of the nanostructures is explored in optimizing the overall device response. Specifically, the effect of the position of the QDs within the intrinsic regions is investigated. Preliminary simulations suggest strategically placing the QDs off-center reduces non-radiative recombination and thereby the dark saturation current, contributing to a marked increase in opencircuit voltage and fill factor. The short-circuit current remains unchanged in the high field region resulting in an increase in overall conversion efficiency. To further explore this finding, a series of three samples with the QDs placed in the center and near the doped regions of a pin-GaAs solar cell have been grown using MOCVD, fabricated and fully characterized. Contrary to predictions, the emitter-shifted devices exhibit a marked decrease in open-circuit voltage and fill factor. This behavior is attributed to non-negligible n-type background doping in the intrinsic region which shifts the region of maximum recombination towards the p-type emitter.
NASA Astrophysics Data System (ADS)
Gao, Hewei; Zhu, Lei; Fahrig, Rebecca
2010-04-01
The impact of the system parameters of the modulator on X-ray scatter correction using primary modulation is studied and an optimization of the modulator design is presented. Recently, a promising scatter correction method for X-ray computed tomography (CT) that uses a checkerboard pattern of attenuating blockers (primary modulator) placed between the X-ray source and the object has been developed and experimentally verified. The blocker size, d, and the blocker transmission factor, α, are critical to the performance of the primary modulation method. In this work, an error caused by aliasing of primary whose magnitude depends on the choices of d and α, and the scanned object, is set as the object function to be minimized, with constraints including the X-ray focal spot, the physical size of the detector element, and the noise level. The optimization is carried out in two steps. In the first step, d is chosen as small as possible but should meet a lower-bound condition. In the second step, α should be selected to balance the error level in the scatter estimation and the noise level in the reconstructed image. The lower bound of d on our tabletop CT system is 0.83 mm. Numerical simulations suggest 0.6 < α < 0.8 is appropriate. Using a Catphan 600 phantom, a copper modulator (d = 0.89 mm, α = 0.70) expectedly outperforms an aluminum modulator (d = 2.83 mm, α = 0.90). With the aluminum modulator, our method reduces the average error of CT number in selected contrast rods from 371.4 to 25.4 Hounsfield units (HU) and enhances the contrast to noise ratio (CNR) from 10.9 to 17.2; when the copper modulator is used, the error is further reduced to 21.9 HU and the CNR is further increased to 19.2.
A new parameter space study of cosmological microlensing
NASA Astrophysics Data System (ADS)
Vernardos, G.; Fluke, C. J.
2013-09-01
Cosmological gravitational microlensing is a useful technique for understanding the structure of the inner parts of a quasar, especially the accretion disc and the central supermassive black hole. So far, most of the cosmological microlensing studies have focused on single objects from ˜90 currently known lensed quasars. However, present and planned all-sky surveys are expected to discover thousands of new lensed systems. Using a graphics processing unit (GPU) accelerated ray-shooting code, we have generated 2550 magnification maps uniformly across the convergence (κ) and shear (γ) parameter space of interest to microlensing. We examine the effect of random realizations of the microlens positions on map properties such as the magnification probability distribution (MPD). It is shown that for most of the parameter space a single map is representative of an average behaviour. All of the simulations have been carried out on the GPU Supercomputer for Theoretical Astrophysics Research.
Theoretical study of the hyperfine parameters of OH
NASA Technical Reports Server (NTRS)
Chong, Delano P.; Langhoff, Stephen R.; Bauschlicher, Charles W., Jr.
1991-01-01
In the present study of the hyperfine parameters of O-17H as a function of the one- and n-particle spaces, all of the parameters except oxygen's spin density, b sub F(O), are sufficiently easily tractable to allow concentration on the computational requirements for accurate determination of b sub F(O). Full configuration-interaction (FCI) calculations in six Gaussian basis sets yield unambiguous results for (1) the effect of uncontracting the O s and p basis sets; (2) that of adding diffuse s and p functions; and (3) that of adding polarization functions to O. The size-extensive modified coupled-pair functional method yields b sub F values which are in fair agreement with FCI results.
Theoretical study of the hyperfine parameters of OH
NASA Technical Reports Server (NTRS)
Chong, Delano P.; Langhoff, Stephen R.; Bauschlicher, Charles W., Jr.
1991-01-01
In the present study of the hyperfine parameters of O-17H as a function of the one- and n-particle spaces, all of the parameters except oxygen's spin density, b sub F(O), are sufficiently easily tractable to allow concentration on the computational requirements for accurate determination of b sub F(O). Full configuration-interaction (FCI) calculations in six Gaussian basis sets yield unambiguous results for (1) the effect of uncontracting the O s and p basis sets; (2) that of adding diffuse s and p functions; and (3) that of adding polarization functions to O. The size-extensive modified coupled-pair functional method yields b sub F values which are in fair agreement with FCI results.
The Statistical Power of the Cluster Randomized Block Design with Matched Pairs--A Simulation Study
ERIC Educational Resources Information Center
Dong, Nianbo; Lipsey, Mark
2010-01-01
This study uses simulation techniques to examine the statistical power of the group- randomized design and the matched-pair (MP) randomized block design under various parameter combinations. Both nearest neighbor matching and random matching are used for the MP design. The power of each design for any parameter combination was calculated from…
GEANT4 for breast dosimetry: parameters optimization study
NASA Astrophysics Data System (ADS)
Fedon, C.; Longo, F.; Mettivier, G.; Longo, R.
2015-08-01
Mean glandular dose (MGD) is the main dosimetric quantity in mammography. MGD evaluation is obtained by multiplying the entrance skin air kerma (ESAK) by normalized glandular dose (DgN) coefficients. While ESAK is an empirical quantity, DgN coefficients can only be estimated with Monte Carlo (MC) methods. Thus, a MC parameters benchmark is needed for effectively evaluating DgN coefficients. GEANT4 is a MC toolkit suitable for medical purposes that offers to the users several computational choices. In this work we investigate the GEANT4 performances testing the main PhysicsLists for medical applications. Four electromagnetic PhysicsLists were implemented: the linear attenuation coefficients were calculated for breast glandularity 0%, 50%, 100% in the energetic range 8-50 keV and DgN coefficients were evaluated. The results were compared with published data. Fit equations for the estimation of the G-factor parameter, introduced by the literature for converting the dose delivered in the heterogeneous medium to that in the glandular tissue, are proposed and the application of this parameter interaction-by-interaction or retrospectively is discussed. G4EmLivermorePhysicsList shows the best agreement for the linear attenuation coefficients both with theoretical values and published data. Moreover, excellent correlation factor ({{r}2}>0.99 ) is found for the DgN coefficients with the literature. The final goal of this study is to identify, for the first time, a benchmark of parameters that could be useful for future breast dosimetry studies with GEANT4.
An algorithm for control system design via parameter optimization. M.S. Thesis
NASA Technical Reports Server (NTRS)
Sinha, P. K.
1972-01-01
An algorithm for design via parameter optimization has been developed for linear-time-invariant control systems based on the model reference adaptive control concept. A cost functional is defined to evaluate the system response relative to nominal, which involves in general the error between the system and nominal response, its derivatives and the control signals. A program for the practical implementation of this algorithm has been developed, with the computational scheme for the evaluation of the performance index based on Lyapunov's theorem for stability of linear invariant systems.
Effect of design and process parameters on nip width of soft calendering
NASA Astrophysics Data System (ADS)
Kanth, Neel; Ray, A. K.; Dang, Riti
2016-07-01
Calendering is a well-known operation in which a material is run between rolls to thin it into sheets or to produce smooth or glossy finish. An attempt has been made in this investigation to remove the drawbacks in the model of Meijers and applicable directly to soft calendering, also to make nip mechanics model generalized and applicable, so that it can be applicable where there is roll to roll or roll to plate contact. Also, the effect of various design and process parameters on results of soft calendering has been discussed using the data taken from paper industry.
Functional relationships of landfill and landraise capacity with design and operation parameters.
Aivaliotis, Vassilis; Dokas, Ioannis; Hatzigiannakou, Maria; Panagiotakopoulos, Demetrios
2004-08-01
Solid waste management presses for effective landfill design and operation. While planning and operating a landfill (LF) or a landraise (LR), choices need to be made regarding: (1) LF-LR morphology (base shape, side slopes, final cover thickness, LR/LF height/depth); (2) cell geometry (height, length, slopes); and (3) operation parameters (waste density, working face length, cover thicknesses). These parameters affect LF/LR capacity, operation lifespan and construction/ operation costs. In this paper, relationships are generated between capacity (C, space available for waste) and the above parameters. Incorporating real data into simulation kgamma A1.38, runs, two types of functions are developed: first, C = where A is the LF/LR base area size and kgamma a base shape-dependent coefficient; and second, C = alpha(p,gamma,A) + delta(p,gamma,A)Xp for every parameter p, where Xp is the value of p and alpha(p,gamma,A) and delta(p,gamma,A) are parameter- and base (shape/size)-specific coefficients. Moreover, the relationship between LF depth and LR height that balances excavation volume with cover material, is identified. Another result is that, for a symmetrical combination of LF/LR, with base surface area shape between square and 1:2 orthogonal, and final density between 500 and 800 kg m(-3), waste quantity placed ranges from 1.76A1.38 to 2.55A1.38 tons. The significance of such functions is obvious, as they allow the analyst to investigate alternative LF/LR schemes and make trade-off analyses.
Coherent Power Analysis in Multilevel Studies Using Parameters from Surveys
ERIC Educational Resources Information Center
Rhoads, Christopher
2017-01-01
Researchers designing multisite and cluster randomized trials of educational interventions will usually conduct a power analysis in the planning stage of the study. To conduct the power analysis, researchers often use estimates of intracluster correlation coefficients and effect sizes derived from an analysis of survey data. When there is…
Dahiya, Shikha; Joseph, Johny
2015-01-01
A high rate biomethanation digester was designed and fabricated to study its real field treatment efficiency and simultaneous biogas generation. The major design parameters like self mixing, delinking hydraulic retention time and solid retention time etc. were considered for efficient performance. It was operated with an organic loading rate (OLR) of 1.5kg/m(3)d(-1) with composite food waste for about one year. The maximum treatment efficiency achieved with respect to total solid (TS) reduction and volatile solids (VS) reduction was 94.5% and 89.7%, respectively. Annual mean biogas of about 0.16m(3)/kgVSd(-1) was observed with methane content varying from 56% to 60% (v/v). The high competence of high rate digester is attributed to its specific design features and intermittent mixing of the digester contents and also due to the hydrodynamic principles involved in its operation.
Response Surface Method for the Rapid Design of Process Parameters in Tube Hydroforming
Chebbah, M. S.; Hecini, M.; Naceur, H.; Belouettar, S.
2007-05-17
This paper deals with the optimization of tube hydroforming parameters in order reduce defects which may occur at the end of forming process such as necking and wrinkling. We propose a specific methodology based on the coupling between an inverse method for the rapid simulation of tube hydroforming process, and a Response Surface Method based on diffuse approximation. The response surfaces are built using Moving Least Squares approximations and constructed within a moving region of interest which moves across a predefined discrete grid of authorized experimental designs. An application of hydroforming of a bulge from aluminium alloy 6061-T6 tubing has been utilized to validate our methodology. The final design is validated with ABAQUS Explicit Dynamic commercial code.
Vonica-Gligor, Andreea Loredana; Tomuţă, Ioan; Leucuţa, Sorin E
2016-06-01
The aim of this work was to develop a pulsatile release system with metoprolol for chronotherapeutical use by coating swellable mini-tablets with Eudragit RS. To study the influence of the formulation factors (amount of coating polymer, plasticizer percentage in film coating and swelling agent percentage in mini-tablets), a Box-Behnken design of experiment (DoE) was used. To evaluate the influence of the studied factors on the sigmoid shape of the dissolution profile, piecewise function parameters were used as the responses of DoE. The results show that higher concentrations of coating polymer and higher concentrations of plasticizer polymer led to a thicker and more elastic polymeric film, which led to a delay in drug release. Using the parameters of the piecewise function as DoE responses, an optimum formulation with a sigmoid shape dissolution profile and a 2.5-h lag time followed by rapid drug release were obtained.
Eldred, Michael Scott; Vigil, Dena M.; Dalbey, Keith R.; Bohnhoff, William J.; Adams, Brian M.; Swiler, Laura Painton; Lefantzi, Sophia; Hough, Patricia Diane; Eddy, John P.
2011-12-01
The DAKOTA (Design Analysis Kit for Optimization and Terascale Applications) toolkit provides a flexible and extensible interface between simulation codes and iterative analysis methods. DAKOTA contains algorithms for optimization with gradient and nongradient-based methods; uncertainty quantification with sampling, reliability, and stochastic expansion methods; parameter estimation with nonlinear least squares methods; and sensitivity/variance analysis with design of experiments and parameter study methods. These capabilities may be used on their own or as components within advanced strategies such as surrogate-based optimization, mixed integer nonlinear programming, or optimization under uncertainty. By employing object-oriented design to implement abstractions of the key components required for iterative systems analyses, the DAKOTA toolkit provides a flexible and extensible problem-solving environment for design and performance analysis of computational models on high performance computers. This report serves as a theoretical manual for selected algorithms implemented within the DAKOTA software. It is not intended as a comprehensive theoretical treatment, since a number of existing texts cover general optimization theory, statistical analysis, and other introductory topics. Rather, this manual is intended to summarize a set of DAKOTA-related research publications in the areas of surrogate-based optimization, uncertainty quantification, and optimization under uncertainty that provide the foundation for many of DAKOTA's iterative analysis capabilities.
Local E-optimality Conditions for Trajectory Design to Estimate Parameters in Nonlinear Systems
Wilson, Andrew D.; Murphey, Todd D.
2014-01-01
This paper develops an optimization method to synthesize trajectories for use in the identification of system parameters. Using widely studied techniques to compute Fisher information based on observations of nonlinear dynamical systems, an infinite-dimensional, projection-based optimization algorithm is formulated to optimize the system trajectory using eigenvalues of the Fisher information matrix as the cost metric. An example of a cart-pendulum simulation demonstrates a significant increase in the Fisher information using the optimized trajectory with decreased parameter variances shown through Monte-Carlo tests and computation of the Cramer-Rao lower bound. PMID:25346569
Design parameters for a stereoptic television system based on direct vision depth perception cues
NASA Technical Reports Server (NTRS)
Shields, N. L., Jr.; Kirkpatrick, M., III; Malone, T. B.; Huggins, C. T.
1975-01-01
Remotely controlled systems which use television for visual feedback require that depth cues be available to the operator. A number of techniques have been developed to provide stereoptic video. An analysis of parameters of such systems as related to the depth cues of convergence and retinal disparity was carried out. Parameter requirements were determined for the provision of natural and exaggerated stereoptic cues and expressions were developed for range resolution limits based on the retinal disparity threshold. An empirical study was conducted using a stereoptic video system to determine threshold values
Oyster Creek cycle 10 nodal model parameter optimization study using PSMS
Dougher, J.D.
1987-01-01
The power shape monitoring system (PSMS) is an on-line core monitoring system that uses a three-dimensional nodal code (NODE-B) to perform nodal power calculations and compute thermal margins. The PSMS contains a parameter optimization function that improves the ability of NODE-B to accurately monitor core power distributions. This functions iterates on the model normalization parameters (albedos and mixing factors) to obtain the best agreement between predicted and measured traversing in-core probe (TIP) reading on a statepoint-by-statepoint basis. Following several statepoint optimization runs, an average set of optimized normalization parameters can be determined and can be implemented into the current or subsequent cycle core model for on-line core monitoring. A statistical analysis of 19 high-power steady-state state-points throughout Oyster Creek cycle 10 operation has shown a consistently poor virgin model performance. The normalization parameters used in the cycle 10 NODE-B model were based on a cycle 8 study, which evaluated only Exxon fuel types. The introduction of General Electric (GE) fuel into cycle 10 (172 assemblies) was a significant fuel/core design change that could have altered the optimum set of normalization parameters. Based on the need to evaluate a potential change in the model normalization parameters for cycle 11 and in an attempt to account for the poor cycle 10 model performance, a parameter optimization study was performed.
Bouillon-Pichault, Marion; Jullien, Vincent; Bazzoli, Caroline; Pons, Gérard; Tod, Michel
2011-02-01
The aim of this work was to determine whether optimizing the study design in terms of ages and sampling times for a drug eliminated solely via cytochrome P450 3A4 (CYP3A4) would allow us to accurately estimate the pharmacokinetic parameters throughout the entire childhood timespan, while taking into account age- and weight-related changes. A linear monocompartmental model with first-order absorption was used successively with three different residual error models and previously published pharmacokinetic parameters ("true values"). The optimal ages were established by D-optimization using the CYP3A4 maturation function to create "optimized demographic databases." The post-dose times for each previously selected age were determined by D-optimization using the pharmacokinetic model to create "optimized sparse sampling databases." We simulated concentrations by applying the population pharmacokinetic model to the optimized sparse sampling databases to create optimized concentration databases. The latter were modeled to estimate population pharmacokinetic parameters. We then compared true and estimated parameter values. The established optimal design comprised four age ranges: 0.008 years old (i.e., around 3 days), 0.192 years old (i.e., around 2 months), 1.325 years old, and adults, with the same number of subjects per group and three or four samples per subject, in accordance with the error model. The population pharmacokinetic parameters that we estimated with this design were precise and unbiased (root mean square error [RMSE] and mean prediction error [MPE] less than 11% for clearance and distribution volume and less than 18% for k(a)), whereas the maturation parameters were unbiased but less precise (MPE < 6% and RMSE < 37%). Based on our results, taking growth and maturation into account a priori in a pediatric pharmacokinetic study is theoretically feasible. However, it requires that very early ages be included in studies, which may present an obstacle to the
Engineering Parameters in Bioreactor's Design: A Critical Aspect in Tissue Engineering
Amoabediny, Ghassem; Pouran, Behdad; Tabesh, Hadi; Shokrgozar, Mohammad Ali; Haghighipour, Nooshin; Khatibi, Nahid; Mottaghy, Khosrow; Zandieh-Doulabi, Behrouz
2013-01-01
Bioreactors are important inevitable part of any tissue engineering (TE) strategy as they aid the construction of three-dimensional functional tissues. Since the ultimate aim of a bioreactor is to create a biological product, the engineering parameters, for example, internal and external mass transfer, fluid velocity, shear stress, electrical current distribution, and so forth, are worth to be thoroughly investigated. The effects of such engineering parameters on biological cultures have been addressed in only a few preceding studies. Furthermore, it would be highly inefficient to determine the optimal engineering parameters by trial and error method. A solution is provided by emerging modeling and computational tools and by analyzing oxygen, carbon dioxide, and nutrient and metabolism waste material transports, which can simulate and predict the experimental results. Discovering the optimal engineering parameters is crucial not only to reduce the cost and time of experiments, but also to enhance efficacy and functionality of the tissue construct. This review intends to provide an inclusive package of the engineering parameters together with their calculation procedure in addition to the modeling techniques in TE bioreactors. PMID:24000327
Estimating parameters of hidden Markov models based on marked individuals: use of robust design data
Kendall, William L.; White, Gary C.; Hines, James E.; Langtimm, Catherine A.; Yoshizaki, Jun
2012-01-01
Development and use of multistate mark-recapture models, which provide estimates of parameters of Markov processes in the face of imperfect detection, have become common over the last twenty years. Recently, estimating parameters of hidden Markov models, where the state of an individual can be uncertain even when it is detected, has received attention. Previous work has shown that ignoring state uncertainty biases estimates of survival and state transition probabilities, thereby reducing the power to detect effects. Efforts to adjust for state uncertainty have included special cases and a general framework for a single sample per period of interest. We provide a flexible framework for adjusting for state uncertainty in multistate models, while utilizing multiple sampling occasions per period of interest to increase precision and remove parameter redundancy. These models also produce direct estimates of state structure for each primary period, even for the case where there is just one sampling occasion. We apply our model to expected value data, and to data from a study of Florida manatees, to provide examples of the improvement in precision due to secondary capture occasions. We also provide user-friendly software to implement these models. This general framework could also be used by practitioners to consider constrained models of particular interest, or model the relationship between within-primary period parameters (e.g., state structure) and between-primary period parameters (e.g., state transition probabilities).
Collisionless expansion of pulsed radio frequency plasmas. II. Parameter study
NASA Astrophysics Data System (ADS)
Schröder, T.; Grulke, O.; Klinger, T.; Boswell, R. W.; Charles, C.
2016-01-01
The plasma parameter dependencies of the dynamics during the expansion of plasma are studied with the use of a versatile particle-in-cell simulation tailored to a plasma expansion experiment [Schröder et al., J. Phys. D: Appl. Phys. 47, 055207 (2014); Schröder et al., Phys. Plasmas 23, 013511 (2016)]. The plasma expansion into a low-density ambient plasma features a propagating ion front that is preceding a density plateau. It has been shown that the front formation is entangled with a wave-breaking mechanism, i.e., an ion collapse [Sack and Schamel, Plasma Phys. Controlled Fusion 27, 717 (1985); Sack and Schamel, Phys. Lett. A 110, 206 (1985)], and the launch of an ion burst [Schröder et al., Phys. Plasmas 23, 013511 (2016)]. The systematic parameter study presented in this paper focuses on the influence on this mechanism its effect on the maximum velocity of the ion front and burst. It is shown that, apart from the well known dependency of the front propagation on the ion sound velocity, it also depends sensitively on the density ratio between main and ambient plasma density. The maximum ion velocity depends further on the initial potential gradient, being mostly influenced by the plasma density ratio in the source and expansion regions. The results of the study are compared with independent numerical studies.
Entrance window design parameters for high-pressure gas x-ray imaging detectors.
Jordan, L M; Dibianca, F A
1995-01-01
Gas ionization x-ray detectors operating at pressures up to 100 atm offer inherently high spatial and contrast resolution. However, incorporating the detector x-ray entrance window in a conventional pressure vessel designed for such pressures can result in high primary beam loss in the window and a much reduced overall detective quantum efficiency. The design of a gas chamber cover plate for a strip beam detector which mechanically isolates the x-ray entrance window from the lateral tensile stresses in the chamber body is described. A number of test windows of this design, varying in three geometric parameters-thickness, window curvature, and fillet radius-were fabricated from wrought aluminum [6061-T651 ] and subjected to pressures of up to 400 atm for the purpose of selecting an optimum window for a prototype digital x-ray imaging detector. The experimental data indicate that windows can be designed for a detector admitting a 1.0 cm wide x-ray beam that have rupture pressures exceeding 500 atm while maintaining x-ray transmittances of as much as 93.4% for a 120 kVp tungsten anode spectrum.
Optimizing Design Parameters for Sets of Concentric Tube Robots using Sampling-based Motion Planning
Baykal, Cenk; Torres, Luis G.; Alterovitz, Ron
2015-01-01
Concentric tube robots are tentacle-like medical robots that can bend around anatomical obstacles to access hard-to-reach clinical targets. The component tubes of these robots can be swapped prior to performing a task in order to customize the robot’s behavior and reachable workspace. Optimizing a robot’s design by appropriately selecting tube parameters can improve the robot’s effectiveness on a procedure-and patient-specific basis. In this paper, we present an algorithm that generates sets of concentric tube robot designs that can collectively maximize the reachable percentage of a given goal region in the human body. Our algorithm combines a search in the design space of a concentric tube robot using a global optimization method with a sampling-based motion planner in the robot’s configuration space in order to find sets of designs that enable motions to goal regions while avoiding contact with anatomical obstacles. We demonstrate the effectiveness of our algorithm in a simulated scenario based on lung anatomy. PMID:26951790
Baykal, Cenk; Torres, Luis G; Alterovitz, Ron
2015-09-28
Concentric tube robots are tentacle-like medical robots that can bend around anatomical obstacles to access hard-to-reach clinical targets. The component tubes of these robots can be swapped prior to performing a task in order to customize the robot's behavior and reachable workspace. Optimizing a robot's design by appropriately selecting tube parameters can improve the robot's effectiveness on a procedure-and patient-specific basis. In this paper, we present an algorithm that generates sets of concentric tube robot designs that can collectively maximize the reachable percentage of a given goal region in the human body. Our algorithm combines a search in the design space of a concentric tube robot using a global optimization method with a sampling-based motion planner in the robot's configuration space in order to find sets of designs that enable motions to goal regions while avoiding contact with anatomical obstacles. We demonstrate the effectiveness of our algorithm in a simulated scenario based on lung anatomy.
A new LPV modeling approach using PCA-based parameter set mapping to design a PSS.
Jabali, Mohammad B Abolhasani; Kazemi, Mohammad H
2017-01-01
This paper presents a new methodology for the modeling and control of power systems based on an uncertain polytopic linear parameter-varying (LPV) approach using parameter set mapping with principle component analysis (PCA). An LPV representation of the power system dynamics is generated by linearization of its differential-algebraic equations about the transient operating points for some given specific faults containing the system nonlinear properties. The time response of the output signal in the transient state plays the role of the scheduling signal that is used to construct the LPV model. A set of sample points of the dynamic response is formed to generate an initial LPV model. PCA-based parameter set mapping is used to reduce the number of models and generate a reduced LPV model. This model is used to design a robust pole placement controller to assign the poles of the power system in a linear matrix inequality (LMI) region, such that the response of the power system has a proper damping ratio for all of the different oscillation modes. The proposed scheme is applied to controller synthesis of a power system stabilizer, and its performance is compared with a tuned standard conventional PSS using nonlinear simulation of a multi-machine power network. The results under various conditions show the robust performance of the proposed controller.
NASA Astrophysics Data System (ADS)
Schnelle, Fabian; Eberhard, Peter
2017-06-01
This paper presents a novel adaptive nonlinear model predictive control design for trajectory tracking of flexible-link manipulators consisting of feedback linearization, linear model predictive control, and unscented Kalman filtering. Reducing the nonlinear system to a linear system by feedback linearization simplifies the optimization problem of the model predictive controller significantly, which, however, is no longer linear in the presence of parameter uncertainties and can potentially lead to an undesired dynamical behaviour. An unscented Kalman filter is used to approximate the dynamics of the prediction model by an online parameter estimation, which leads to an adaptation of the optimization problem in each time step and thus to a better prediction and an improved input action. Finally, a detailed fuzzy-arithmetic analysis is performed in order to quantify the effect of the uncertainties on the control structure and to derive robustness assessments. The control structure is applied to a serial manipulator with two flexible links containing uncertain model parameters and acting in three-dimensional space.
Franco, R; Gavaldà, M T; Canela, E I
1986-01-01
A method of model discrimination and parameter estimation in enzyme kinetics is proposed. The experimental design and analysis of the model are carried out simultaneously and the stopping rule for experimentation is deduced by the experimenter when the probabilities a posteriori indicate that one model is clearly superior to the rest. A FORTRAN77 program specifically developed for joint designs is given. The method is very powerful, as indicated by its usefulness in the discrimination between models. For example, it has been successfully applied to three cases of enzyme kinetics (a single-substrate Michaelian reaction with product inhibition, a single-substrate complex reaction and a two-substrate reaction). By using this method the most probable model and the estimates of the parameters can be obtained in one experimental session. The FORTRAN77 program is deposited as Supplementary Publication SUP 50134 (19 pages) at the British Library (Lending Division), Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1986) 233, 5. PMID:3800965
Robust control design with real parameter uncertainty using absolute stability theory. Ph.D. Thesis
NASA Technical Reports Server (NTRS)
How, Jonathan P.; Hall, Steven R.
1993-01-01
The purpose of this thesis is to investigate an extension of mu theory for robust control design by considering systems with linear and nonlinear real parameter uncertainties. In the process, explicit connections are made between mixed mu and absolute stability theory. In particular, it is shown that the upper bounds for mixed mu are a generalization of results from absolute stability theory. Both state space and frequency domain criteria are developed for several nonlinearities and stability multipliers using the wealth of literature on absolute stability theory and the concepts of supply rates and storage functions. The state space conditions are expressed in terms of Riccati equations and parameter-dependent Lyapunov functions. For controller synthesis, these stability conditions are used to form an overbound of the H2 performance objective. A geometric interpretation of the equivalent frequency domain criteria in terms of off-axis circles clarifies the important role of the multiplier and shows that both the magnitude and phase of the uncertainty are considered. A numerical algorithm is developed to design robust controllers that minimize the bound on an H2 cost functional and satisfy an analysis test based on the Popov stability multiplier. The controller and multiplier coefficients are optimized simultaneously, which avoids the iteration and curve-fitting procedures required by the D-K procedure of mu synthesis. Several benchmark problems and experiments on the Middeck Active Control Experiment at M.I.T. demonstrate that these controllers achieve good robust performance and guaranteed stability bounds.
Electron work function–a promising guiding parameter for material design
Lu, Hao; Liu, Ziran; Yan, Xianguo; Li, Dongyang; Parent, Leo; Tian, Harry
2016-01-01
Using nickel added X70 steel as a sample material, we demonstrate that electron work function (EWF), which largely reflects the electron behavior of materials, could be used as a guide parameter for material modification or design. Adding Ni having a higher electron work function to X70 steel brings more “free” electrons to the steel, leading to increased overall work function, accompanied with enhanced e−–nuclei interactions or higher atomic bond strength. Young’s modulus and hardness increase correspondingly. However, the free electron density and work function decrease as the Ni content is continuously increased, accompanied with the formation of a second phase, FeNi3, which is softer with a lower work function. The decrease in the overall work function corresponds to deterioration of the mechanical strength of the steel. It is expected that EWF, a simple but fundamental parameter, may lead to new methodologies or supplementary approaches for metallic materials design or tailoring on a feasible electronic base. PMID:27074974
Design parameters for a biomass harvester for short-rotation, hardwood stands
Gibson, H.G.; Pope, P.E.
1984-01-01
Design parameters were developed from field tests and mathematical simulations methods. Serving methods, tyres versus tracks, and compaction were evaluated from field tests. Power, weight, tractive effort and speed requirements were determined from simulation methods. Method of harvest (sawing or shearing) had no significant influence on coppice DM production of individual stumps. However, shearing of the 1 x 1 and 0.5 x 1 m spacing produced more DM from sprouts than shearing at other spacings or sawing at any spacing. Tracked vehicles caused more stump damage than rubber-tyred vehicles for both species tested. Productivity of the stumps was inversely related to stump damage, though productivity significantly declined only for stumps assessed as being heavily damaged. Succeeding passes of the pneumatic tyred tractor over randomized subplots resulted in increased soil strength and density down to 15.2 cm. Compaction did not affect the number of sprouts produced at 0, 2, 6, or 10 passes but did significantly reduce sprout height at 6 and 10 passes. Using an optimization technique, an analysis was made to determine parameters for the design of the harvester. 12 references.
Novel Compressor Blade Design Study
NASA Astrophysics Data System (ADS)
Srinivas, Abhay
Jet engine efficiency goals are driving compressors to higher pressure ratios and engines to higher bypass ratios, each one driving to smaller cores. This is leading to larger tip gaps relative to the blade height. These larger relative tip clearances would negate some of the cycle improvements, and ways to mitigate this effect must be found. A novel split tip blade geometry has been created which helps improve the efficiency at large clearances while also improving operating range. Two identical blades are leaned in opposite directions starting at 85% span. They are cut at mid chord and the 2 halves then merged together so a split tip is created. The result is similar to the alula feathers on a soaring bird. The concept is that the split tip will energize the tip flow and increase range. For higher relative tip clearance, this will also improve efficiency. The 6th rotor of a highly loaded 10 stage machine was chosen as the baseline for this study. Three dimensional CFD simulations were performed using CD Adapco's Star-CCM+ at 5 clearances for the baseline and split tip geometry. The choking flow and stall margin of the split tip blade was higher than that of the baseline blade for all tip clearances. The pressure ratio of the novel blade was higher than that of the baseline blade near choke, but closer to stall it decreased. The sensitivity of peak efficiency to clearance was improved. At tight clearances of 0.62% of blade height, the maximum efficiency of the new design was less than the baseline blade, but as the tip clearance was increased above 2.5%, the maximum efficiency increased. Structural analysis was also performed to ascertain the feasibility of the design.
Characterizing parameters of Jatropha curcas cell cultures for microgravity studies
NASA Astrophysics Data System (ADS)
Vendrame, Wagner A.; Pinares, Ania
2013-06-01
Jatropha (Jatropha curcas) is a tropical perennial species identified as a potential biofuel crop. The oil is of excellent quality and it has been successfully tested as biodiesel and in jet fuel mixes. However, studies on breeding and genetic improvement of jatropha are limited. Space offers a unique environment for experiments aiming at the assessment of mutations and differential gene expression of crops and in vitro cultures of plants are convenient for studies of genetic variation as affected by microgravity. However, before microgravity studies can be successfully performed, pre-flight experiments are necessary to characterize plant material and validate flight hardware environmental conditions. Such preliminary studies set the ground for subsequent spaceflight experiments. The objectives of this study were to compare the in vitro growth of cultures from three explant sources (cotyledon, leaf, and stem sections) of three jatropha accessions (Brazil, India, and Tanzania) outside and inside the petriGAP, a modified group activation pack (GAP) flight hardware to fit petri dishes. In vitro jatropha cell cultures were established in petri dishes containing a modified MS medium and maintained in a plant growth chamber at 25 ± 2 °C in the dark. Parameters evaluated were surface area of the explant tissue (A), fresh weight (FW), and dry weight (DW) for a period of 12 weeks. Growth was observed for cultures from all accessions at week 12, including subsequent plantlet regeneration. For all accessions differences in A, FW and DW were observed for inside vs. outside the PetriGAPs. Growth parameters were affected by accession (genotype), explant type, and environment. The type of explant influenced the type of cell growth and subsequent plantlet regeneration capacity. However, overall cell growth showed no abnormalities. The present study demonstrated that jatropha in vitro cell cultures are suitable for growth inside PetriGAPs for a period of 12 weeks. The parameters
Ling, Jing; Qian, Li-Xuan; Ding, Jun-Jie; Jiao, Zheng
2014-05-01
The purpose of this study is to investigate the effects of multiple-trough sampling design and nonlinear mixed effect modeling (NONMEM) algorithm on the estimation of population and individual pharmacokinetic parameters. Oxcarbazepine and tacrolimus were used as one-compartment and two-compartment model drugs, respectively. Seven sampling designs were investigated using various number of trough concentrations per individual ranging from 1-4. Monte Carlo simulations were performed to produce state-steady trough concentrations. One-compartment model was used to fit simulated data from oxcarbazepine and tacrolimus. The accuracy and precision of the estimated parameters were evaluated using the median prediction error (PE), the median absolute PE and boxplot. The results indicated that trough concentrations could yield reliable estimates of apparent clearance (CL/F). For oxcarbazepine, as the number of trough concentrations per subject increased, the accuracy and precision of CL/F, between-subject variability (BSV) of CL/F and residual variability (RUV) tended to be improved. For tacrolimus, however, although no improvement were observed in the accuracy of CL/F and BSV of CL/F, the PE distribution ranges were significantly narrowed and the RUV estimates were less bias and imprecise. In terms of algorithm, Monte Carlo importance sampling (IMP) and IMP assisted by mode a posteriori estimation (IMPMAP) were consistently better than other methods. Additionally, the sampling design had no significant effects on the individual parameter estimates, which were only depended on the interaction between BSV and RUV in various algorithms. Decreased in BSV and RUV levels can improve the accuracy and precision of the estimation for both population and individual pharmacokinetic parameter estimates.
Simulation studies on performance parameters of a TPC polarimeter
NASA Astrophysics Data System (ADS)
Rakhee, K.; Koushal, V.; Radhakrishna, V.; Baishali, G.; A. M., Vinodkumar
2014-07-01
X-ray polarimeters based on Time Projection Chamber (TPC) geometry are currently being studied and developed to make sensitive measurement of polarization in 2-10keV energy range. TPC soft X-ray polarimeters exploit the fact that emission direction of the photoelectron ejected via photoelectric effect in a gas proportional counter carries the information of the polarization of the incident X-ray photon. Operating parameters such as pressure, drift field and driftgap affect the performance of a TPC polarimeter. Simulations presented here showcase the effect of these operating parameters on the modulation factor of the TPC polarimeter. Models of Garfield are used to study photoelectron interaction in gas and drift of electron cloud towards Gas Electron Multiplier (GEM). The emission direction is reconstructed from the image and modulation factor is computed. Our study has shown that Ne/DME (50/50) at lower pressure and drift field can be used for a TPC polarimeter with modulation factor of 50-65%.
Advanced Subsonic Airplane Design and Economic Studies
NASA Technical Reports Server (NTRS)
Liebeck, Robert H.; Andrastek, Donald A.; Chau, Johnny; Girvin, Raquel; Lyon, Roger; Rawdon, Blaine K.; Scott, Paul W.; Wright, Robert A.
1995-01-01
A study was made to examine the effect of advanced technology engines on the performance of subsonic airplanes and provide a vision of the potential which these advanced engines offered. The year 2005 was selected as the entry-into-service (EIS) date for engine/airframe combination. A set of four airplane classes (passenger and design range combinations) that were envisioned to span the needs for the 2005 EIS period were defined. The airframes for all classes were designed and sized using 2005 EIS advanced technology. Two airplanes were designed and sized for each class: one using current technology (1995) engines to provide a baseline, and one using advanced technology (2005) engines. The resulting engine/airframe combinations were compared and evaluated on the basis on sensitivity to basic engine performance parameters (e.g. SFC and engine weight) as well as DOC+I. The advanced technology engines provided significant reductions in fuel burn, weight, and wing area. Average values were as follows: reduction in fuel burn = 18%, reduction in wing area = 7%, and reduction in TOGW = 9%. Average DOC+I reduction was 3.5% using the pricing model based on payload-range index and 5% using the pricing model based on airframe weight. Noise and emissions were not considered.
NASA Astrophysics Data System (ADS)
Reimer, Joscha; Piwonski, Jaroslaw; Slawig, Thomas
2016-04-01
The statistical significance of any model-data comparison strongly depends on the quality of the used data and the criterion used to measure the model-to-data misfit. The statistical properties (such as mean values, variances and covariances) of the data should be taken into account by choosing a criterion as, e.g., ordinary, weighted or generalized least squares. Moreover, the criterion can be restricted onto regions or model quantities which are of special interest. This choice influences the quality of the model output (also for not measured quantities) and the results of a parameter estimation or optimization process. We have estimated the parameters of a three-dimensional and time-dependent marine biogeochemical model describing the phosphorus cycle in the ocean. For this purpose, we have developed a statistical model for measurements of phosphate and dissolved organic phosphorus. This statistical model includes variances and correlations varying with time and location of the measurements. We compared the obtained estimations of model output and parameters for different criteria. Another question is if (and which) further measurements would increase the model's quality at all. Using experimental design criteria, the information content of measurements can be quantified. This may refer to the uncertainty in unknown model parameters as well as the uncertainty regarding which model is closer to reality. By (another) optimization, optimal measurement properties such as locations, time instants and quantities to be measured can be identified. We have optimized such properties for additional measurement for the parameter estimation of the marine biogeochemical model. For this purpose, we have quantified the uncertainty in the optimal model parameters and the model output itself regarding the uncertainty in the measurement data using the (Fisher) information matrix. Furthermore, we have calculated the uncertainty reduction by additional measurements depending on time
Study of Dill's B parameter measurement of EUV resist
NASA Astrophysics Data System (ADS)
Sekiguchi, Atsushi; Matsumoto, Yoko; Harada, Tetsuo; Watanabe, Takeo; Kinoshita, Hiroo
2015-03-01
Our group previously explored methods for measuring simulation parameter for advanced chemically amplified (CA) resists, including development parameters [1]. Dill's C parameter [2-3] , acid diffusion length generated from PAG [4], and de-protection reaction parameters [5-6]. We performed simulations of EUV resists using these parameters, the results of which allowed us to examine the conditions for reducing LER and improving resolution. This paper discusses a method for measuring the Dill's B parameter, which had been difficult to measure with conventional methods. We also confirmed that enhancing the resist polymer's EUV light absorption is effective in improving the sensitivity of the CA resist.
Protecting count queries in study design
Sarwate, Anand D; Boxwala, Aziz A
2012-01-01
Objective Today's clinical research institutions provide tools for researchers to query their data warehouses for counts of patients. To protect patient privacy, counts are perturbed before reporting; this compromises their utility for increased privacy. The goal of this study is to extend current query answer systems to guarantee a quantifiable level of privacy and allow users to tailor perturbations to maximize the usefulness according to their needs. Methods A perturbation mechanism was designed in which users are given options with respect to scale and direction of the perturbation. The mechanism translates the true count, user preferences, and a privacy level within administrator-specified bounds into a probability distribution from which the perturbed count is drawn. Results Users can significantly impact the scale and direction of the count perturbation and can receive more accurate final cohort estimates. Strong and semantically meaningful differential privacy is guaranteed, providing for a unified privacy accounting system that can support role-based trust levels. This study provides an open source web-enabled tool to investigate visually and numerically the interaction between system parameters, including required privacy level and user preference settings. Conclusions Quantifying privacy allows system administrators to provide users with a privacy budget and to monitor its expenditure, enabling users to control the inevitable loss of utility. While current measures of privacy are conservative, this system can take advantage of future advances in privacy measurement. The system provides new ways of trading off privacy and utility that are not provided in current study design systems. PMID:22511018
Experimental study of turbulence parameters in braided river
NASA Astrophysics Data System (ADS)
Khan, M. A.; Sharma, N.
2016-12-01
A turbulent phenomenon in a braided river is much more complex as compared to the straight and meandering rivers. Turbulent flow characteristics around the braid bar are not thoroughly studied till now. The results of measurements of three-dimensional velocities carried out in a laboratory model of braided river are presented in this paper. Quadrant analysis was performed which demonstrated the importance of ejection and sweep phases in sediment detachment and transport. This paper describes the results of an experimental study on the turbulence flow characteristics at points around the bar in a braided river model. The measurements of velocity near the braided bar were made at 12 different locations using an ADV. The turbulent characteristics of flow are plotted against the flow depth for 5 vertical sections. From the results, it was found that the maximum value of turbulent kinetic energy, Reynolds shear stress, and the turbulence intensity was found to occur near the bed level. These turbulent parameters have greater values for scouring points, this shows that these parameters are related with the scouring near the braided bar. The concept of the hole is used for filtering out the extreme events that are responsible for burst. The conditional probability of quadrant events is plotted against the hole size for four near bed points around the braided river model. Results show that the conditional probability of dominant events increases as the size of hole increases.
Flanagan, C.A.
1984-10-01
This document is a design overview that describes the scoping studies and preconceptual design effort performed in FY 1983 on the Tokamak Fusion Core Experiment (TFCX) class of device. These studies focussed on devices with all-superconducting toroidal field (TF) coils and on devices with superconducting TF coils supplemented with copper TF coil inserts located in the bore of the TF coils in the shield region. Each class of device is designed to satisfy the mission of ignition and long pulse equilibrium burn. Typical design parameters are: major radius = 3.75 m, minor radius = 1.0 m, field on axis = 4.5 T, plasma current = 7.0 MA. These designs relay on lower hybrid (LHRH) current rampup and heating to ignition using ion cyclotron range of frequency (ICRF). A pumped limiter has been assumed for impurity control. The present document is a design overview; a more detailed design description is contained in a companion document.
NASA Astrophysics Data System (ADS)
Ragab, Kh. A.; Bouaicha, A.; Bouazara, M.
2017-09-01
The semi-solid casting process has the advantage of providing reliable mechanical aluminum parts that work continuously in dynamic as control arm of the suspension system in automotive vehicles. The quality performance of dynamic control arm is related to casting mold and gating system designs that affect the fluidity of semi-solid metal during filling the mold. Therefore, this study focuses on improvement in mechanical performance, depending on material characterization, and casting design optimization, of suspension control arms made of A357 aluminum semi-solid alloys. Mechanical and design analyses, applied on the suspension arm, showed the occurrence of mechanical failures at unexpected weak points. Metallurgical analysis showed that the main reason lies in the difficult flow of semi-solid paste through the thin thicknesses of a complex geometry. A design modification procedure is applied to the geometry of the suspension arm to avoid this problem and to improve its quality performance. The design modification of parts was carried out by using SolidWorks design software, evaluation of constraints with ABAQUS, and simulation of flow with ProCast software. The proposed designs showed that the modified suspension arm, without ribs and with a central canvas designed as Z, is considered as a perfect casting design showing an increase in the structural strength of the component. In this case, maximum von Mises stress is 199 MPa that is below the yield strength of the material. The modified casting mold design shows a high uniformity and minim turbulence of molten metal flow during semi-solid casting process.
ERIC Educational Resources Information Center
Gao, Furong; Chen, Lisue
2005-01-01
Through a large-scale simulation study, this article compares item parameter estimates obtained by the marginal maximum likelihood estimation (MMLE) and marginal Bayes modal estimation (MBME) procedures in the 3-parameter logistic model. The impact of different prior specifications on the MBME estimates is also investigated using carefully…
Parameter Design of Logic-Based Controller for Two-Wheeled Vehicle
NASA Astrophysics Data System (ADS)
Konaka, Eiji; Mutou, Takashi; Suzuki, Tatsuya
Programmable Logic Controllers (PLCs) are widely used in industrial world. In PLC-based control systems, low-resolution (especially ON/OFF) sensors are low-cost, and actuators are commonly used since they are compatible with programming languages used in PLCs. PLC switches ON/OFF of the actuators as ON/OFF of the sensors changes. In designing PLC-based systems, the design of parameters of these sensors and actuators (e.g., position of limit switches, torque of motors, and so on.) is important problem since they affect on overall performance of the system. This problem, however, has not been fully discussed yet. In this paper, the systematic design method for this problem is developed. The main idea is to express the model of the system as Mixed Logical Dynamical System (MLDS), and to formulate the problem as mathematical programming problem. The developed idea is applied to line following control of two-wheeled vehicle. The usefulness of the proposed method is demonstrated through simulation and experiment.
NASA Astrophysics Data System (ADS)
van Munster, Bjorn; Prinssen, Wim
2003-10-01
Acoustic enhancement systems have evolved significantly during the years. Where the early systems only aimed to increase the reverberation time in a hall, nowadays the increase of the reverberation time is only one of the features of such a system. Contrary and additionally to passive acoustics, an acoustic enhancement system enables a designer or acoustical consultant to change the acoustical characteristics of a hall in a more flexible way. Due to the sophisticated convolution processes and layout of such a system besides the reverberation time also, e.g., speech intelligibility and spaciousness can be improved or special effects can be added to shows. In this paper the applications of an enhancement system in general will be outlined in more detail. Furthermore, design criteria will be given which can be formulated for the installation of such a system. These criteria can be used to evaluate proposed designs, but also to estimate the required provisions to be included in the planning of a system installation. Besides, the paper describes the results of in situ measurements of one such system (SIAP) whereby the increase of the reverberation time is evaluated with respect to certain important room acoustical parameters, i.e., reverberant level, lateral efficiency and clarity.
NASA Astrophysics Data System (ADS)
Rybus, Tomasz; Seweryn, Karol
2016-03-01
All devices designed to be used in space must be thoroughly tested in relevant conditions. For several classes of devices the reduced gravity conditions are the key factor. In early stages of development and later due to financial reasons, the tests need to be done on Earth. However, in Earth conditions it is impossible to obtain a different gravity field independent on all linear and rotational spatial coordinates. Therefore, various test-bed systems are used, with their design driven by the device's specific needs. One of such test-beds are planar air-bearing microgravity simulators. In such an approach, the tested objects (e.g., manipulators intended for on-orbit operations or vehicles simulating satellites in a close formation flight) are mounted on planar air-bearings that allow almost frictionless motion on a flat surface, thus simulating microgravity conditions in two dimensions. In this paper we present a comprehensive review of research activities related to planar air-bearing microgravity simulators, demonstrating achievements of the most active research groups and describing newest trends and ideas, such as tests of landing gears for low-g bodies. Major design parameters of air-bearing test-beds are also reviewed and a list of notable existing test-beds is presented.
Kanojia, Gaurav; Willems, Geert-Jan; Frijlink, Henderik W; Kersten, Gideon F A; Soema, Peter C; Amorij, Jean-Pierre
2016-09-25
Spray dried vaccine formulations might be an alternative to traditional lyophilized vaccines. Compared to lyophilization, spray drying is a fast and cheap process extensively used for drying biologicals. The current study provides an approach that utilizes Design of Experiments for spray drying process to stabilize whole inactivated influenza virus (WIV) vaccine. The approach included systematically screening and optimizing the spray drying process variables, determining the desired process parameters and predicting product quality parameters. The process parameters inlet air temperature, nozzle gas flow rate and feed flow rate and their effect on WIV vaccine powder characteristics such as particle size, residual moisture content (RMC) and powder yield were investigated. Vaccine powders with a broad range of physical characteristics (RMC 1.2-4.9%, particle size 2.4-8.5μm and powder yield 42-82%) were obtained. WIV showed no significant loss in antigenicity as revealed by hemagglutination test. Furthermore, descriptive models generated by DoE software could be used to determine and select (set) spray drying process parameter. This was used to generate a dried WIV powder with predefined (predicted) characteristics. Moreover, the spray dried vaccine powders retained their antigenic stability even after storage for 3 months at 60°C. The approach used here enabled the generation of a thermostable, antigenic WIV vaccine powder with desired physical characteristics that could be potentially used for pulmonary administration.
Mastropasqua, Leonardo; Calienno, Roberta; Lanzini, Manuela; Salgari, Niccolò; De Vecchi, Sergio; Mastropasqua, Rodolfo; Nubile, Mario
2017-06-01
The purpose of this study was to evaluate the incidence of opaque bubble layer (OBL) in femtosecond laser-assisted in situ keratomileusis (LASIK) flaps created with the support of Visumax Carl Zeiss femtosecond laser, planned with different flap diameters (7.90, 8.0, and 8.20 mm) and the same laser energy and power settings. Incidence of intraoperative OBL in flaps of consecutive 108 patients (216 eyes) subjected to bilateral femtosecond-assisted LASIK was considered. Flap creation was performed with the same laser design parameters (spot distance and energy offset) and different presetting diameters of 7.90 mm (72 eyes, group 1), 8 mm (72 eyes, group 2), and 8.20 mm (72 eyes, group 3). The incidence of OBL was considered and its extension was reported measuring involvement of different four corneal flap quadrants in which was theoretically divided the entire flap area; based on these data, OBL presence was classified as none (no evidence of OBL), minimal (minimal presence in not more that one quadrants corneal flap), mild (OBL presence in almost two or three quadrants without tendency to invade central cornea), and moderate (OBL presence in almost three quadrants with tendency to invade central cornea). In group 1, the incidence of OBL was of 23.6 % (17 eyes) with a mild/moderate presence; in group 2, incidence was 20.8 % (15 eyes) with mild presence. Group 3 presented a reduced OBL incidence (4.1 %, 3 eye) with a minimal presence. No statistically significant difference was found between group 1 and 2 (p = 0.8414).We found statistically significant differences between group 1 and group 3 (p = 0.0012) and between groups 2 and 3 (p = 0.0044). A significant reduction and extension of OBL incidence were evident when LASIK flap settings diameter was increased, and flap edge was closer to the contact glass border; this is probably consequent to a more effective gas dispersion outside of corneal flap.
Investigation of the effect of physical parameters on the design of tumour targeting agents
NASA Astrophysics Data System (ADS)
Casey, Joanne Lois
Tumour targeting using radiolabelled antibodies for radioimmunodetection (RAID) and radioimmunotherapy (RIT) has been studied for many years. The main factors that have limited clinical success are low tumour uptake, immunogenicity and poor therapeutic ratios. This thesis has applied current technology to make advances in this area of research. The effect of physical parameters (antibody size, valency, affinity and charge) on the design of tumour targeting agents was studied by constructing divalent (DFM) and trivalent (TFM) forms of the murine anti-CEA antibody A5B7 Fab' by chemical cross-linking. This involves partial reduction of the hinge disulphides to expose thiol (-SH) groups and subsequent reaction with a maleimide cross-linker to form a thioether bond at the hinge region. Previous studies have suggested that the stability of thioether bonds is superior to naturally occurring disulphide bonds present at the hinge region of IgG and F(ab')2. The aim was to compare the functional affinities and in vivo tumour targeting in nude mice bearing human tumour xenografts of DFM and TFM to similar sized parent IgG and F(ab')2. Radiolabelling with 131I and 90Y was also compared with a view to determine which combination would be optimal for RIT. Results clearly demonstrated a significantly faster on-rate of DFM compared to all other antibody forms and estimated dosimetry analysis suggested that DFM would be the most suitable antibody form radiolabelled with 131I for RIT. Both F(ab')2 and DFM showed high kidney uptake levels on labelling with which is unacceptable for RIT. Despite the improved tumour: blood ratios for TFM, the increased estimated dose to normal tissues and lower therapeutic effect in RIT studies suggests that the most promising combination with the radionuclide appears to be IgG. A humanised version of A5B7 hFab' has been constructed previously in order to reduce its immunogenicity in man. The in vivo stability of hDFM proved to be superior to hF(ab')2
NASA Astrophysics Data System (ADS)
Potters, M. G.; Mansoori, M.; Bombois, X.; Jansen, J. D.; Van den Hof, P. M. J.
2016-03-01
This paper considers Pressure Oscillation (PO) experiments for which we find the minimum experiment time that guarantees user-imposed parameter variance upper bounds and honours actuator limits. The parameters permeability and porosity are estimated with a classical least-squares estimation method for which an expression of the covariance matrix of the estimates is calculated. This expression is used to tackle the optimization problem. We study the Dynamic Darcy Cell experiment set-up (Heller et al., 2002) and focus on data generation using square wave actuator signals, which, as we shall prove, deliver shorter experiment times than sinusoidal ones. Parameter identification is achieved using either inlet pressure/outlet pressure measurements (Heller et al., 2002) or actuator position/outlet pressure measurements, where the latter is a novel approach. The solution to the optimization problem reveals that for both measurement methods an optimal excitation frequency, an optimal inlet volume, and an optimal outlet volume exist. We find that under the same parameter variance bounds and actuator constraints, actuator position/outlet pressure measurements result in required experiment times that are a factor fourteen smaller compared to inlet pressure/outlet pressure measurements. This result is analysed in detail and we find that the dominant effect driving this difference originates from an identifiability problem when using inlet-outlet pressure measurements for joint estimation of permeability and porosity. We illustrate our results with numerical simulations, and show excellent agreement with theoretical expectations.
[Input impedance for studying hydraulic parameters of the vessel system].
Naumov, A Iu; Sheptutsolov, K V; Balashov, S A; Mel'kumiants, A M
2001-03-01
Vascular input impedance can be used as an effective tool in estimating hydraulic parameters of arterial bed. These parameters may be interpreted as hydraulic resistance, elastance and inertance of particular sites of the arterial system. There is no significant difference between these parameters and those obtained through a direct measurement.
A Prospective Study of Anterior Segment Ocular Parameters in Anisometropia
Rohatgi, Jolly; Kumar, Vinod
2017-01-01
Purpose The aim of this study was to investigate the differences in anterior segment ocular parameters in anisometropia >1 D. Methods This study included 202 eyes of 101 subjects ranging from 10 to 40 years of age with anisometropia of 1 D or more. The subjects were divided into groups according to anisomyopia, anisoastigmatism, and anisohypermetropia. After providing informed consent, each patient underwent a detailed ophthalmological examination including cycloplegic refraction, best-corrected visual acuity, cover test, axial length (AL) measurement using A-scan ultrasound biometer, keratometry, anterior chamber depth, and central corneal thickness measurement. For each participant, the eye with greater refractive error was compared to the fellow eye via paired t-tests. Correlations between parameters were studied using the Pearson correlation coefficient. Results The average age of subjects was 21.7 ± 9.3 years. Of 101 subjects, 31 had anisomyopia; 42 had anisohypermetropia; and 28 had anisoastigmatism. A predisposition toward greater myopia in right eyes was noted in anisomyopia (24 of 31 subjects, 77%). The inter-ocular acuity difference was significant in all three groups (p < 0.01). As the degree of anisometropia increased, there was significant positive correlation in the difference in AL in myopes (r = 0.863, p < 0.01) and hypermetropes (r = 0.669, p < 0.01) and the difference in corneal curvature in anisoastigmatism (r = 0.564, p = 0.002) and hypermetropes (r = 0.376, p = 0.014). A significant positive correlation was also present between the anterior chamber depth difference and refractive difference in hypermetropes (r = 0.359, p = 0.020). Conclusions This study showed that anisomyopia is correlated only with anterior chamber differences. Anisohypermetropia is correlated with AL differences as well as corneal curvature difference and anterior chamber depth difference. The amount of anisoastigmatism correlates only with corneal curvature difference
Chenel, Marylore; Ogungbenro, Kayode; Duval, Vincent; Laveille, Christian; Jochemsen, Roeline; Aarons, Leon
2005-12-01
The objective of this paper is to determine optimal blood sampling time windows for the estimation of pharmacokinetic (PK) parameters by a population approach within the clinical constraints. A population PK model was developed to describe a reference phase II PK dataset. Using this model and the parameter estimates, D-optimal sampling times were determined by optimising the determinant of the population Fisher information matrix (PFIM) using PFIM_ _M 1.2 and the modified Fedorov exchange algorithm. Optimal sampling time windows were then determined by allowing the D-optimal windows design to result in a specified level of efficiency when compared to the fixed-times D-optimal design. The best results were obtained when K(a) and IIV on K(a) were fixed. Windows were determined using this approach assuming 90% level of efficiency and uniform sample distribution. Four optimal sampling time windows were determined as follow: at trough between 22 h and new drug administration; between 2 and 4 h after dose for all patients; and for 1/3 of the patients only 2 sampling time windows between 4 and 10 h after dose, equal to [4 h-5 h 05] and [9 h 10-10 h]. This work permitted the determination of an optimal design, with suitable sampling time windows which was then evaluated by simulations. The sampling time windows will be used to define the sampling schedule in a prospective phase II study.
Anser, Humera; Najam, Raheela; Khan, Saira Saeed; Riaz, Bushra; Sarfaraz, Sana
2014-09-01
Several plants have been selected based on their use in traditional systems of medicine, and research has identified a number of natural compounds that could act as Nootropicagents. In this study a herbal product Intellan containing Centella asiatica, Bacopa monniera, Coriandum sativum, Amomum subulatum, Emblica officinalis and another product Cytacon (Cyanocobalamine) were selected The study was designed on animal models to explore the effects on different parameters. For this the animals were given chronic dosing for 6-8 weeks during and after which the parameters were observed to determine their effects. The purpose of focusing on such formulations is to do hematological screening in long-term use. The hematological parameter included hemoglobin/HCT, total leucocyte count, platelets. The lymphocytes and the monocytes counts were increased significantly by intellan, while cyanocobalamine increases RBC counts, platelet counts, monocyte counts, hematocrit etc significantly. The SGPT, SGOT were found increased in both of these drugs.
ERIC Educational Resources Information Center
Turkall, Sheila Florian
1996-01-01
Describes an integrated student-designed investigation in which students explore different aspects of the Chagrin River including the river ecosystem, velocity and average depth, river flooding, water quality, and economic and political factors. (JRH)
ERIC Educational Resources Information Center
Turkall, Sheila Florian
1996-01-01
Describes an integrated student-designed investigation in which students explore different aspects of the Chagrin River including the river ecosystem, velocity and average depth, river flooding, water quality, and economic and political factors. (JRH)
A study of parameters useful for describing plasma-opening switches
Mendel, C.W. Jr.; Seidel, D.B.; Rosenthal, S.E.
1998-09-01
Plasma opening switches (POS) have been used continually and studied since their introduction in 1975. During that period they have performed well for prepulse suppression and sharpening the front of the power pulse. Their use for long conduction time and rapid opening to stand off high voltage in the same POS has met with very limited success. There has been a large theoretical effort involving models and particle-in-cell simulations (PICS), but the connection between theory and experiment has been tenuous at best, and convincing agreement with experiment has been minimal. The authors believe progress toward long conduction and rapid opening would be faster if macroscopic physical parameters describing the physics of the switch were used to compare experiment to simulation. One of these parameters (electron flow impedance) has been used to describe the electrical characteristics of the POS. This parameter provides a good description of both the standard POS (SPOS) and the magnetically controlled POS (MCPOS) because its value is sensibly independent of load current. An additional parameter, the effective mass of the plasma, was measured in one MCPOS experiment. In this article they describe other parameters important to operation of the SPOS and the MCPOS, and parameters important in designing PICS used to study these devices.
Shirsat, Ajinath Eknath; Chitlange, Sohan S
2015-01-01
The purpose of present study was to optimize rizatriptan (RZT) chitosan (CS) nanoparticles using ionic gelation method by application of quality by design (QbD) approach. Based on risk assessment, effect of three variables, that is CS %, tripolyphosphate % and stirring speed were studied on critical quality attributes (CQAs); particle size and entrapment efficiency. Central composite design (CCD) was implemented for design of experimentation with 20 runs. RZT CS nanoparticles were characterized for particle size, polydispersity index, entrapment efficiency, in-vitro release study, differential scanning calorimetric, X-ray diffraction, scanning electron microscopy (SEM). Based on QbD approach, design space (DS) was optimized with a combination of selected variables with entrapment efficiency > 50% w/w and a particle size between 400 and 600 nm. Validation of model was performed with 3 representative formulations from DS for which standard error of - 0.70-3.29 was observed between experimental and predicted values. In-vitro drug release followed initial burst release 20.26 ± 2.34% in 3-4 h with sustained drug release of 98.43 ± 2.45% in 60 h. Lower magnitude of standard error for CQAs confirms the validation of selected CCD model for optimization of RZT CS nanoparticles. In-vitro drug release followed dual mechanism via, diffusion and polymer erosion. RZT CS nanoparticles were prepared successfully using QbD approach with the understanding of the high risk process and formulation parameters involved and optimized DS with a multifactorial combination of critical parameters to obtain predetermined RZT loaded CS nanoparticle specifications.
Shirsat, Ajinath Eknath; Chitlange, Sohan S.
2015-01-01
The purpose of present study was to optimize rizatriptan (RZT) chitosan (CS) nanoparticles using ionic gelation method by application of quality by design (QbD) approach. Based on risk assessment, effect of three variables, that is CS %, tripolyphosphate % and stirring speed were studied on critical quality attributes (CQAs); particle size and entrapment efficiency. Central composite design (CCD) was implemented for design of experimentation with 20 runs. RZT CS nanoparticles were characterized for particle size, polydispersity index, entrapment efficiency, in-vitro release study, differential scanning calorimetric, X-ray diffraction, scanning electron microscopy (SEM). Based on QbD approach, design space (DS) was optimized with a combination of selected variables with entrapment efficiency > 50% w/w and a particle size between 400 and 600 nm. Validation of model was performed with 3 representative formulations from DS for which standard error of − 0.70–3.29 was observed between experimental and predicted values. In-vitro drug release followed initial burst release 20.26 ± 2.34% in 3–4 h with sustained drug release of 98.43 ± 2.45% in 60 h. Lower magnitude of standard error for CQAs confirms the validation of selected CCD model for optimization of RZT CS nanoparticles. In-vitro drug release followed dual mechanism via, diffusion and polymer erosion. RZT CS nanoparticles were prepared successfully using QbD approach with the understanding of the high risk process and formulation parameters involved and optimized DS with a multifactorial combination of critical parameters to obtain predetermined RZT loaded CS nanoparticle specifications. PMID:26317071
The Relationship between Parameters of Long-Latency Evoked Potentials in a Multisensory Design.
Hernández, Oscar H; García-Martínez, Rolando; Monteón, Victor
2016-10-01
In previous papers, we have shown that parameters of the omitted stimulus potential (OSP), which occurs at the end of a train of sensory stimuli, strongly depend on the modality. A train of stimuli also produces long-latency evoked potentials (LLEP) at the beginning of the train. This study is an extension of the OSP research, and it tested the relationship between parameters (ie, rate of rise, amplitude, and peak latency) of the P2 waves when trains of auditory, visual, or somatosensory stimuli were applied. The dynamics of the first 3 potentials in the train, related to habituation, were also studied. Twenty healthy young college volunteers participated in the study. As in the OSP, the P2 was faster and higher for auditory than for visual or somatosensory stimuli. The first P2 was swifter and higher than the second and the third potentials. The strength of habituation depends on the sensory modality and the parameter used. All these findings support the view that many long-latency brain potentials could share neural mechanisms related to wave generation.
Design Study: Rocket Based MHD Generator
NASA Technical Reports Server (NTRS)
1997-01-01
This report addresses the technical feasibility and design of a rocket based MHD generator using a sub-scale LOx/RP rocket motor. The design study was constrained by assuming the generator must function within the performance and structural limits of an existing magnet and by assuming realistic limits on (1) the axial electric field, (2) the Hall parameter, (3) current density, and (4) heat flux (given the criteria of heat sink operation). The major results of the work are summarized as follows: (1) A Faraday type of generator with rectangular cross section is designed to operate with a combustor pressure of 300 psi. Based on a magnetic field strength of 1.5 Tesla, the electrical power output from this generator is estimated to be 54.2 KW with potassium seed (weight fraction 3.74%) and 92 KW with cesium seed (weight fraction 9.66%). The former corresponds to a enthalpy extraction ratio of 2.36% while that for the latter is 4.16%; (2) A conceptual design of the Faraday MHD channel is proposed, based on a maximum operating time of 10 to 15 seconds. This concept utilizes a phenolic back wall for inserting the electrodes and inter-electrode insulators. Copper electrode and aluminum oxide insulator are suggested for this channel; and (3) A testing configuration for the sub-scale rocket based MHD system is proposed. An estimate of performance of an ideal rocket based MHD accelerator is performed. With a current density constraint of 5 Amps/cm(exp 2) and a conductivity of 30 Siemens/m, the push power density can be 250, 431, and 750 MW/m(sup 3) when the induced voltage uB have values of 5, 10, and 15 KV/m, respectively.
Carbon Nanotubes as FET Channel: Analog Design Optimization considering CNT Parameter Variability
NASA Astrophysics Data System (ADS)
Samar Ansari, Mohd.; Tripathi, S. K.
2017-08-01
Carbon nanotubes (CNTs), both single-walled as well as multi-walled, have been employed in a plethora of applications pertinent to semiconductor materials and devices including, but not limited to, biotechnology, material science, nanoelectronics and nano-electro mechanical systems (NEMS). The Carbon Nanotube Field Effect Transistor (CNFET) is one such electronic device which effectively utilizes CNTs to achieve a boost in the channel conduction thereby yielding superior performance over standard MOSFETs. This paper explores the effects of variability in CNT physical parameters viz. nanotube diameter, pitch, and number of CNT in the transistor channel, on the performance of a chosen analog circuit. It is further shown that from the analyses performed, an optimal design of the CNFETs can be derived for optimizing the performance of the analog circuit as per a given specification set.
Prosthesis-user-in-the-loop: user-centered design parameters and visual simulation.
Christ, O; Wojtusch, J; Beckerle, P; Wolff, K; Vogt, J; von Stryk, O; Rinderknecht, S
2012-01-01
After an amputation, processes of change in the body image as well as a change in body scheme have direct influences on the quality of living in every patient. Within this paper, a paradigm of experimental induced body illusion (the Rubber Hand Illusion, RHI) is integrated in a prosthetic hardware simulator concept. This concept combines biodynamical and visual feedback to enhance the quality of rehabilitation and to integrate patients' needs into the development of prostheses aiming on user-centered solutions. Therefore, user-centered design parameters are deducted. Furthermore, the basic concept of the visual simulation is presented and a possibility for its implementation is given. Finally, issues and conclusions for future work are described.
A study of commuter airplane design optimization
NASA Technical Reports Server (NTRS)
Roskam, J.; Wyatt, R. D.; Griswold, D. A.; Hammer, J. L.
1977-01-01
Problems of commuter airplane configuration design were studied to affect a minimization of direct operating costs. Factors considered were the minimization of fuselage drag, methods of wing design, and the estimated drag of an airplane submerged in a propellor slipstream; all design criteria were studied under a set of fixed performance, mission, and stability constraints. Configuration design data were assembled for application by a computerized design methodology program similar to the NASA-Ames General Aviation Synthesis Program.
A STUDY OF PARAMETERS AND METHODS INVOLVED IN RELATIVE DISPLACEMENT MEASUREMENTS IN SOIL.
A study of the parameters and methods involved in relative displacement measurements in soil was conducted. Static tests were performed to assess the...found in spool gage displacement measurements. Stress wave reflections and gage lengths are discussed with reference to dynamic data collected in...is employed to measure relative displacements in soil. These criteria were applied to the design of a spool gage which was tested and compared with
Effect of cigarette design on biomarkers of exposure, puffing topography and respiratory parameters.
Appleton, Scott; Liu, Jianmin; Lipowicz, Peter J; Sarkar, Mohamadi
2015-02-01
Despite the lack of evidence, many reports exist which have implied that smokers inhale low-yield cigarette smoke more deeply than that of high-yield cigarettes. The objective of this study was to investigate the effect of short-term switching between smoker's own brand and test cigarettes with different smoke yields on puffing topography, respiratory parameters and biomarkers of exposure. Participants were randomly assigned to smoke either a Test Cigarette-High Tar (TCH), for two days, and then switched to a Test Cigarette-Low Tar (TCL), for two days or the reverse order (n = 10 each sequence). Puffing topography (CReSS microdevice), respiratory parameters (inductive plethysmography) and biomarkers of exposure (BOE, urinary nicotine equivalents - NE and blood carboxyhemoglobin - COHb) were measured at baseline and on days 2 and 4. The average puffs per cigarette, puff volume and puff durations were statistically significantly lower, and inter-puff interval was significantly longer for the TCH compared to the TCL groups. Respiratory parameters were not statistically significantly different between the TCH and TCL groups. Post-baseline NE and COHb were statistically significantly lower in the TCL compared to the TCH groups. Under the conditions of this study, we found no indication of changes in respiratory parameters, particularly inhalation time and volume, between study participants smoking lower versus higher yield cigarettes. Likewise, the BOE provides no indication of deeper inhalation when smoking low- versus high-yield cigarettes. These findings are consistent with the published literature indicating smoking low-yield cigarettes does not increase the depth of inhalation.
NASA Astrophysics Data System (ADS)
Magis, T.; Ballerand, S.; Bellemin Comte, A.; Pollet, Olivier
2013-03-01
Micro-system for biology is a growing market, especially for micro-fluidic applications (environment and health). Key part for the manufacturing of biology MEMS is the deep silicon etching by plasma to create microstructures. Usual etching process as an alternation of etching and passivation steps is a well-known method for MEMS fabrication, nowadays used in high volume production for devices like sensors and actuators. MEMS for biology applications are very different in design compared to more common micro-systems like accelerometers for instance. Indeed, their design includes on the same chip structures of very diverse size like narrow pillars, large trenches and wide cavities. This makes biology MEMS fabrication very challenging for DRIE, since each type of feature considered individually would require a specific etch process. Furthermore process parameters suited to match specifications on small size features (vertical profile, low sidewall roughness) induce issues and defects on bigger structures (undercut, micro-masking) and vice versa. Thus the process window is constrained leading to trade-offs in process development. In this paper process parameters such as source and platen powers, pressure, etching and passivation gas flows and steps duration were investigated to achieve all requirements. As well interactions between those different factors were characterized at different levels, from individual critical feature up to chip scale and to wafer scale. We will show the plasma process development and tuning to reach all these specifications. We also compared different chambers configurations of our ICP tool (source wafer distance, plasma diffusion) in order to obtain a good combination of hardware and process. With optimized etching we successfully fabricate micro-fluidic devices like micro-pumps.
NASA Astrophysics Data System (ADS)
Zhao, Jing-Shan; Li, Lingyang; Chen, Liping; Zhang, Yunqing
2010-12-01
This paper starts with a classical mechanism synthesis problem and focuses on the concept design and dynamics analysis of an independent suspension that has invariable orientation parameters when the wheel moves up (jounces) and down (rebounds). The paper first proposes a symmetric redundant constraint suspension structure that has invariable orientation parameters. And then, it analyses the mechanism mobility with the reciprocal screw theory, after which it establishes the displacement constraint equations of the suspension. This type of suspension has all the advantages of the sliding pillar suspension but overcomes its disadvantage of over-wearing. Through differentiating the constraint equations with respect to time, it obtains the kinematics relationship and builds up the dynamics equations of the suspension via Newton-Euler method. Numerical simulations indicate that this kind of independent suspensions should not only eliminate the shambling shocks induced by the jumping of wheels but also decrease the abrasion of the wheels. Therefore, this kind of independent suspensions can obviously improve the ride and handling properties of advanced automobiles.
Advanced Design Studies. Final report
Steiner, Don
2012-12-01
The ARIES-CS project was a multi-year multi-institutional project to assess the feasibility of a compact stellarator as a fusion power plant. The work herein describes efforts to help design one aspect of the device, the divertor, which is responsible for the removal of particle and heat flux from the system, acting as the first point of contact between the magnetically confined hot plasma and the outside world. Specifically, its location and topology are explored, extending previous work on the sub ject. An optimized design is determined for the thermal particle flux using a suite of 3D stellarator design codes which trace magnetic field lines from just inside the confined plasma edge to their strike points on divertor plates. These divertor plates are specified with a newly developed plate design code. It is found that a satisfactory thermal design exists which maintains the plate temperature and heat load distribution below tolerable engineering limits. The design is unique, including a toroidal taper on the outboard plates which was found to be important to our results. The maximum thermal heat flux for the final design was 3.61 M W/m2 and the maximum peaking factor was 10.3, below prescribed limits of 10 M W/m2 and 15.6, respectively. The median length of field lines reaching the plates is about 250 m and their average angle of inclination to the surface is 2 deg. Finally, an analysis of the fast alphas, resulting from fusion in the core, which escape the plasma was performed. A method is developed for obtaining the mapping from magnetic coordinates to real-space coordinates for the ARIES-CS. This allows the alpha exit locations to be identified in real space for the first time. These were then traced using the field line algorithm as well as a guiding center routine accounting for their mass, charge, and specific direction and energy. Results show that the current design is inadequate for accommodating the alpha heat flux, capturing at most 1/3 of lost alphas
Parameter Sensitivity Study of the Wall Interference Correction System (WICS)
NASA Technical Reports Server (NTRS)
Walker, Eric L.; Everhart, Joel L.; Iyer, Venkit
2001-01-01
An off-line version of the Wall Interference Correction System (WICS) has been implemented for the "NASA Langley National Transonic Facility. The correction capability is currently restricted to corrections for solid wall interference in the model pitch plane for Mach numbers, less than 0.45 due to a limitation in tunnel calibration data. A study to assess output sensitivity to the aerodynamic parameters of Reynolds number and Mach number was conducted on this code to further ensure quality during the correction process. In addition, this paper includes all investigation into possible correction due to a semispan test technique using a non metric standoff and all improvement to the standard data rejection algorithm.
Reverse design and characteristic study of multi-range HMCVT
NASA Astrophysics Data System (ADS)
Zhu, Zhen; Chen, Long; Zeng, Falin
2017-09-01
The reduction of fuel consumption and increase of transmission efficiency is one of the key problems of the agricultural machinery. Many promising technologies such as hydromechanical continuously variable transmissions (HMCVT) are the focus of research and investments, but there is little technical documentation that describes the design principle and presents the design parameters. This paper presents the design idea and characteristic study of HMCVT, in order to find out the suitable scheme for the big horsepower tractors. Analyzed the kinematics and dynamics of a large horsepower tractor, according to the characteristic parameters, a hydro-mechanical continuously variable transmission has been designed. Compared with the experimental curves and theoretical curves of the stepless speed regulation of transmission, the experimental result illustrates the rationality of the design scheme.
Result-driven exploration of simulation parameter spaces for visual effects design.
Bruckner, Stefan; Möller, Torsten
2010-01-01
Graphics artists commonly employ physically-based simulation for the generation of effects such as smoke, explosions, and similar phenomena. The task of finding the correct parameters for a desired result, however, is difficult and time-consuming as current tools provide little to no guidance. In this paper, we present a new approach for the visual exploration of such parameter spaces. Given a three-dimensional scene description, we utilize sampling and spatio-temporal clustering techniques to generate a concise overview of the achievable variations and their temporal evolution. Our visualization system then allows the user to explore the simulation space in a goal-oriented manner. Animation sequences with a set of desired characteristics can be composed using a novel search-by-example approach and interactive direct volume rendering is employed to provide instant visual feedback. A user study was performed to evaluate the applicability of our system in production use.
From BRDF to roughness: defining the link between two key parameters for optical design
NASA Astrophysics Data System (ADS)
Kuperman-Le Bihan, Quentin
2015-09-01
Link between roughness and Bidirectional Scatter Distribution Function (BSDF) is a challenging issue but a necessary step for designers. Indeed optical designers often speak about scattering where manufacturers speak about roughness. This link would enable an easier understanding between both parts, ending up with better designs. Besides, optical design software deal very well with BSDF, but ray tracing time can be strongly impacted when you have a lot of them in your design. Therefore, replacing BSDF by a real geometrical shape such as the roughness could be of a big benefit. How can we link BSDF to roughness? We worked on two ways of finding a link between BSDF and roughness. From measured BSDF with Reflet Bench, we tried to find the equivalent roughness using He-Torrance model. Still using He-Torrance model we also tried to compute the BSDF knowing a roughness profile from a sample. The study showed great results with specular samples. When roughness is at least ten times bigger than the wavelength, roughness could be estimated within 5% precision. Above this limit, roughness can still be computed but with a 50% precision, which gives us at least an order of magnitude estimation. We also found with our method that, the more scattering the sample is, the more difficult it is to estimate roughness. Thanks to such a link between roughness and BSDF, it becomes much easier to understand how to go from one to the other. This can be very useful for optical designers, but also for manufacturer who wants to perform roughness measurement. Designers who need a certain scattering for their optical designs, can therefore easily speak with manufacturers by giving them a roughness value to perform the BSDF they are looking for.
Study of fluid parameters in high pressure descaling valves
NASA Astrophysics Data System (ADS)
Adhikari, Param; Panta, Yogendra
2012-11-01
Our work is focused on the high pressure valves used for descaling purposes in steel mills. A reverse flow operation was set in one of such valves due to piping constraints. Computational approaches are being utilized to understand the fluid phenomena at such high pressures. Though the valve geometry accounts for the complete fluid flow path, a study has been initiated from an axisymmetric model of the valve core. The highly energized fluid from the descaling pump sets off a static pressure of 5000 psi at the valve inlet. It is responsible for continuous fluid flow rate of up to 208 gpm for fully open position. A Shear Stress Transport turbulence model is utilized to study pressure at nearly closed position of the poppet part while Renormalization Group Turbulence model is compared with Shear Stress Transport turbulence model for full opening position. A very low pressure developed below the poppet seat suggests the onset of cavitation zones which may lead to leakage. A full 3D model is studied after a complete studies of fluid phenomenon in the axisymmetric geometry. Using ANSYS Fluent, a commercial CFD software package, the poppet valve assembly was processed for modeling, meshing and setting up of physical parameters. Computational results show the cavitation intensities higher at small openings than at larger openings which is further verified by literature research and currently comparing with experiments.
Advances on ELIC Design Studies
Bogacz, S. Alex; Bogacz, S.; Chevtsov, P.; Derbenev, Ya.; Evtushenko, P.; Krafft, G.; Hutton, A.; Li, R.; Merminga, L.; Musson, J.; Yunn, B.; Zhang, Y.; Sayed, H.; Qiang, J.
2008-06-16
A conceptual design of a ring-ring electron-ion collider based on CEBAF with a center-of-mass energy up to 90 GeV at luminosity up to 1035 cm-2s-1 has been proposed at JLab to fulfil science requirements. Here, we summarize design progress including collider ring and interaction region optics with chromatic aberration compensation. Electron polarization in the Figure-8 ring, stacking of ion beams in an accumulator-cooler ring, beam-beam simulations and a faster kicker for the circulator electron cooler ring are also discussed.
NASA Technical Reports Server (NTRS)
Tompkins, M. A.; Cheng, D. E. (Principal Investigator)
1981-01-01
The design and implementation of the PARPLT program are described. The program produces scatter plots of the greenness profile derived parameters alpha, beta, and t sub o computed by the CLASFYG program (alpha being the approximate greenness rise time; beta, the greenness decay time; and t sub o, the spectral crop emergence date). Statistical information concerning the parameters is also computed.
Design Concept and Parameters of a 15 T $Nb_{3}Sn$ Dipole Demonstrator for a 100 TEV Hadron Collider
Zlobin, A. V.; Andreev, N.; Barzi, E.; Kashikhin, V. V.; Novitski, I.
2015-06-01
FNAL has started the development of a 15 T $Nb_{3}Sn$ dipole demonstrator for a 100 TeV scale hadron collider. This paper describes the design concept and parameters of the 15 T $Nb_{3}Sn$ dipole demonstrator. The dipole magnetic, mechanical and quench protection concept and parameters are presented and discussed.
Designing occupancy studies when false-positive detections occur
Clement, Matthew
2016-01-01
1.Recently, estimators have been developed to estimate occupancy probabilities when false-positive detections occur during presence-absence surveys. Some of these estimators combine different types of survey data to improve estimates of occupancy. With these estimators, there is a tradeoff between the number of sample units surveyed, and the number and type of surveys at each sample unit. Guidance on efficient design of studies when false positives occur is unavailable. 2.For a range of scenarios, I identified survey designs that minimized the mean square error of the estimate of occupancy. I considered an approach that uses one survey method and two observation states and an approach that uses two survey methods. For each approach, I used numerical methods to identify optimal survey designs when model assumptions were met and parameter values were correctly anticipated, when parameter values were not correctly anticipated, and when the assumption of no unmodelled detection heterogeneity was violated. 3.Under the approach with two observation states, false positive detections increased the number of recommended surveys, relative to standard occupancy models. If parameter values could not be anticipated, pessimism about detection probabilities avoided poor designs. Detection heterogeneity could require more or fewer repeat surveys, depending on parameter values. If model assumptions were met, the approach with two survey methods was inefficient. However, with poor anticipation of parameter values, with detection heterogeneity, or with removal sampling schemes, combining two survey methods could improve estimates of occupancy. 4.Ignoring false positives can yield biased parameter estimates, yet false positives greatly complicate the design of occupancy studies. Specific guidance for major types of false-positive occupancy models, and for two assumption violations common in field data, can conserve survey resources. This guidance can be used to design efficient
Adelman, D.D.; Stansbury, J.
1997-12-31
The Resource Conservation and Recovery Act (RCRA) Subtitle C, Comprehensive Environmental Response, Compensation, And Liability Act (CERCLA), and subsequent amendments have formed a comprehensive framework to deal with hazardous wastes on the national level. Key to this waste management is guidance on design (e.g., cover and bottom leachate control systems) of hazardous waste landfills. The objective of this research was to investigate the sensitivity of leachate volume at hazardous waste disposal sites to climatic, soil cover, and vegetative cover (Leaf Area Index) conditions. The computer model HELP3 which has the capability to simulate double bottom liner systems as called for in hazardous waste disposal sites was used in the analysis. HELP3 was used to model 54 combinations of climatic conditions, disposal site soil surface curve numbers, and leaf area index values to investigate how sensitive disposal site leachate volume was to these three variables. Results showed that leachate volume from the bottom double liner system was not sensitive to these parameters. However, the cover liner system leachate volume was quite sensitive to climatic conditions and less sensitive to Leaf Area Index and curve number values. Since humid locations had considerably more cover liner system leachate volume than and locations, different design standards may be appropriate for humid conditions than for and conditions.
Waveguide Parameter Design of Graded-Index Plastic Optical Fibers for Bending-Loss Reduction
NASA Astrophysics Data System (ADS)
Makino, Kenji; Ishigure, Takaaki; Koike, Yasuhiro
2006-05-01
The waveguide structure of graded-index plastic optical fibers (GI POFs), such as index profile, numerical aperture (NA), and core diameter, is appropriately designed for eliminating bending losses, even under a severe bending condition. The bending loss of GI POFs under a severe bending condition is drastically reduced when the core diameter is smaller than 200 µm and when the NA is higher than 0.25. The bending loss of GI POFs even under a severe bending condition vanishes with a core diameter of 200 µm and an NA of 0.24. It is experimentally confirmed for the first time that the mode coupling due to the bending induces the bending loss. The mode coupling strength before the fiber is bent affects the bending loss seriously. Moreover, the mode-coupling strength is evaluated by the propagation constant difference Δβ between the adjacent modes. The Δβ value, which is a function of the core diameter and NA, affects the bending loss. Therefore, based on the calculation of the Δβ, we propose a guideline for the appropriate design of waveguide parameters for GI POF, in order to suppress the bending loss.
Output-feedback sampled-data control design for linear parameter-varying systems with delay
NASA Astrophysics Data System (ADS)
Ramezanifar, Amin; Mohammadpour, Javad; Grigoriadis, Karolos M.
2014-12-01
In this paper, we address the sampled-data output-feedback control design problem for continuous-time linear parameter-varying systems with time-varying delay in the system states. Due to the combination of the plant's continuous-time dynamics and the controller's discrete-time dynamics connected through A/D and D/A converter devices, the closed-loop system is a hybrid system. In order to analyse this hybrid system from stability and performance perspectives we use the input-delay approach to map the closed-loop system into the continuous-time domain with delay in the states. This results in a closed-loop system containing two types of delays, the system internal delay and the one imposed by the mapping. Next, we use delay-dependent conditions for analysis of stability and ?-norm performance which result in a sampled-data control synthesis procedure. The proposed output-feedback sampled-data controller is obtained based on the solution to a linear matrix inequality optimisation problem using a set of appropriately defined slack variables. A numerical example of a milling machine is presented to demonstrate the viability of the proposed sampled-data control design method to satisfy the stability and performance objectives even with a varying sampling rate.
Multimission Aircraft Design Study, Payload
2003-03-01
number MC2A Multisensor Command and Control Aircraft MC2A-X Multisensor Command and Control Aircraft Experiment MIDS Multifunctional Information and...reconnaissance (ISR) fleet. The MMA is alternately designated as the Multisensor Command and Control Aircraft (MC2A) as indicated in this text. Figure
Design of wireless multi-parameter monitoring system for oral feeding of premature infants.
Wang, Yu-Lin; Kuo, Hsing-Chien; Wang, Lin-Yu; Ko, Mei-Ju; Lin, Bor-Shyh
2016-07-01
Premature infants often cannot successfully and coordinately complete their oral feeding. Mature sucking, swallowing, and respiration activities are crucial indicators for the survival of newborn infants. Due to the vulnerability and unobvious muscle activities of premature infants, current clinical care givers mainly depend on the subjective behavioral observation of infants during oral feeding. There is still lack of an integrated oral feeding monitoring system to objectively and quantifiably monitor the related physiological parameters of premature infants. In this study, a wireless multi-parameter monitoring system for oral feeding of premature infants was proposed to monitor the sucking-swallowing-respiratory activities and the heart rate variability to provide quantitative indices of oral feeding. Here, a novel sucking pressure sensing module was also developed to monitor the premature infant's sucking pressure under oral feeding to avoid the immersion influence of milk. The experimental results showed that the proposed system detected the related physiological parameters of premature infants during oral feeding effectively and may provide an objective clinical evaluation tool for oral feeding ability and safety of premature infants in the future.
NASA Astrophysics Data System (ADS)
Jeffrey Kuo, Chung-Feng; Chiu, Hsuan-Yen; Syu, Sheng-Siang; Huy Vu, Quang
2014-01-01
This study investigated the touch panel conductive film processing quality by using a CO2 laser system. The processing material chooses ethylene terephthalate with a size of 10 cm×4 cm. Experimental results measuring the three characteristics included line width, heat-affected zone and bump height. It further analyzed the relationship between the control parameters of a CO2 laser cutting system and the quality characteristics. First, the orthogonal array in the Taguchi Method was applied to plan the experiment. The signal noise ratio (S/N) of the quality characteristics was calculated according to data obtained from the experiments. Second, data were pre-processed using the gray relation method and the processed data showed a relationship between the control parameters and various quality characteristics. Next, the fuzzy inference system was applied to solve the multiple quality characteristics to determine the optimal solution and the combinations of the optimal multiple laser control parameters. Moreover, the Back-Propagation Neural Networks (BPNN) with the Levenberg-Marquardt algorithm was applied to construct a prediction system and simulate experimental results. Finally, the optimal solution was experimentally verified. The results showed that the prediction error rate was within 5%, proving that the proposed prediction system can effectively predict the laser processing of transparent conductive film.
Tan, Zhuo; Ganapathy, Anirudh; Orndorff, Paul E; Shirwaiker, Rohan A
2015-01-01
Post-operative infection is a major risk associated with implantable devices. Prior studies have demonstrated the effectiveness of ionic silver as an alternative to antibiotic-based infection prophylaxis and treatment. The focus of this study is on an electrically activated implant system engineered for active release of antimicrobial silver ions. The objective was to evaluate the effects of the cathode design, especially the cathode material, on the in vitro antimicrobial efficacy of the system. A modified Kirby-Bauer diffusion technique was used for the antimicrobial efficacy evaluations (24 h testing interval). In phase-1 of the study, a three-way ANOVA (n = 6, α = 0.05) was performed to determine the effects of cathode material (silver, titanium, and stainless steel), cathode surface area and electrode separation distance on the efficacy of the system against Staphylococcus aureus. The results show that within the design space tested, none of these parameters had a statistically significant effect on the antimicrobiality of the system (P > 0.15). Subsequently, one-way ANOVA (n = 6, α = 0.05) was conducted in phase-2 to validate the inference regarding the non-significance of the cathode material to the system efficacy using a broader spectrum of pathogens (methicillin-resistant S. aureus, Escherichia coli, Streptococcus agalactiae and Aspergillus flavus) responsible for osteomyelitis. The results confirmed the lack of statistical difference between efficacies of the three cathode material configurations against all pathogens tested (P > 0.58). Overall, the results demonstrate the ability to alter the cathode material and related design parameters in order to minimize the silver usage in the system without adversely affecting its antimicrobial efficacy.
NASA Astrophysics Data System (ADS)
Eckley, C. S.; Gustin, M.; Lin, C.-J.; Li, X.; Miller, M. B.
2010-01-01
Dynamic Flux Chambers (DFCs) are commonly applied for the measurement of non-point source mercury (Hg) emissions from a wide range of surfaces. A standard operating protocol and design for DFCs does not exist, and as a result there is a large diversity in methods described in the literature. Because natural and anthropogenic non-point sources are thought to contribute significantly to the atmosphere Hg pool, development of accurate fluxes during field campaigns is essential. The objective of this research was to determine how differences in chamber material, sample port placement, vertical cross sectional area/volume, and flushing flow rate influence the Hg flux from geologic materials. Hg fluxes measured with a Teflon chamber were higher than those obtained using a polycarbonate chamber, with differences related to light transmission and substrate type. Differences in sample port placement (side versus top) did not have an influence on Hg fluxes. When the same flushing flow rate was applied to two chambers of different volumes, higher fluxes were calculated for the chamber with the smaller volume. Conversely, when two chambers with different volumes were maintained at similar turnover times, the larger volume chamber yielded higher Hg fluxes. Overall, the flushing flow rate and associated chamber turnover time had the largest influence on Hg flux relative to the other parameters tested. Results from computational fluid dynamic (CFD) modeling inside a DFC confirm that the smaller diffusion resistance at higher flushing flows contributes to the higher measured flux. These results clearly illustrate that differences in chamber design and operation can significantly influence the resulting calculated Hg flux, and thus impact the comparability of results obtained using DFC designs and/or operating parameters. A protocol for determining a flushing flow rate that results in fluxes less affected by chamber operating conditions and design is proposed. Application of this
Submersible Aircraft Concept Design Study
2010-08-01
lead to the tips of the wing stalling before the inboard sections, making the aircraft pitch up and potentially stall. In order to combat this, an...the lift being produced by the wing and so reduce hull draft, albeit at the expense of induced drag from the wing . Naval Surface Warfare Center... delta wing design with some blended wing body characteristics was adopted. This approach gives excellent internal volume characteristics whilst
NASA Astrophysics Data System (ADS)
Toghi Eshghi, Amin; Lee, Soobum; Lee, Hanmin; Kim, Young-Cheol
2016-04-01
In this paper, we perform design parameter study and design optimization for a piezoelectric energy harvester considering vehicle speed variation. Initially, a FEM model using ANSYS is developed to appraise the performance of a piezoelectric harvester in a rotating tire. The energy harvester proposed here uses the vertical deformation at contact patch area from the car weight and centrifugal acceleration. This harvester is composed of a beam which is clamped at both ends and a piezoelectric material is attached on the top of that. The piezoelectric material possesses the 31 mode of transduction in which the direction of applied field is perpendicular to that of the electric field. To optimize the harvester performance, we would change the geometrical parameters of the harvester to obtain the maximum power. One of the main challenges in the design process is obtaining the required power while considering the constraints for harvester weight and volume. These two concerns are addressed in this paper. Since the final goal of this study is the development of an energy harvester with a wireless sensor system installed in a real car, the real time data for varied velocity of a vehicle are taken into account for power measurements. This study concludes that the proposed design is applicable to wireless tire sensor systems.
NASA Astrophysics Data System (ADS)
Reimer, J.; Schuerch, M.; Slawig, T.
2015-03-01
The geosciences are a highly suitable field of application for optimizing model parameters and experimental designs especially because many data are collected. In this paper, the weighted least squares estimator for optimizing model parameters is presented together with its asymptotic properties. A popular approach to optimize experimental designs called local optimal experimental designs is described together with a lesser known approach which takes into account the potential nonlinearity of the model parameters. These two approaches have been combined with two methods to solve their underlying discrete optimization problem. All presented methods were implemented in an open-source MATLAB toolbox called the Optimal Experimental Design Toolbox whose structure and application is described. In numerical experiments, the model parameters and experimental design were optimized using this toolbox. Two existing models for sediment concentration in seawater and sediment accretion on salt marshes of different complexity served as an application example. The advantages and disadvantages of these approaches were compared based on these models. Thanks to optimized experimental designs, the parameters of these models could be determined very accurately with significantly fewer measurements compared to unoptimized experimental designs. The chosen optimization approach played a minor role for the accuracy; therefore, the approach with the least computational effort is recommended.
Liu, Huolong; Wang, Ke; Schlindwein, Walkiria; Li, Mingzhong
2013-05-20
In this work, the influence factors of pulsed frequency, binder spray rate and atomisation pressure of a top-spray fluidised bed granulation process were studied using the Box-Behnken experimental design method. Different mathematical models were developed to predict the mean size of granules, yield, relative width of granule distribution, Hausner ratio and final granule moisture content. The study has supported the theory that the granule size can be controlled through the liquid feed pulsing. However, care has to be taken when the pulsed frequency is chosen for controlling the granule size due to the nonlinear quadratic relation in the regression model. The design space of the ranges of operating parameters has been determined based on constraints of the mean size of granules and granule yield. High degree of prediction obtained from validation experiments has shown the reliability and effectiveness of using the Box-Behnken experimental design method to study a fluidised bed granulation process. Copyright © 2013 Elsevier B.V. All rights reserved.
Empirical study of Thompson sampling: Tuning the posterior parameters
NASA Astrophysics Data System (ADS)
Devanand, R.; Kumar, P.
2017-06-01
Thompson sampling (TS) is a natural Bayesian algorithm for the Multi-armed-bandit problems (MABs), a popular model for studying exploration and exploitation trade-off in sequential decision problems. We first study TS for the standard finite armed Bernoulli bandit, where the reward of each arm follows a Bernoulli distribution with an unknown mean. The mean reward of each arm can be modeled as Beta distribution as it is a posterior of the binomial distribution. Without changing the posterior mean we tune the associated posterior parameters using a policy called greedy in the limit with infinite exploration (GLIE) and attempt to balance between exploration and exploitation in the decision making in MAB. The experimental performance comparison based on minimizing the average regret is carried out between our posterior-tuned TS with standard TS algorithm. Upper Confidence Bound (UCB), a popular bandit algorithm is also discussed in brief and the experimental results are performed with our method. The resulting experiment suggests that for a non-asymptotic regime, our posterior-tuned TS works better than TS and UCB methods and, competitive on average.
Bord, Cécile; Guerinon, Delphine; Lebecque, Annick
2016-07-01
The aim of this study was to measure the impact of heating on the sensory properties of blue-veined cheeses in order to characterise their sensory properties and to identify their specific sensory typology associated with physicochemical parameters. Sensory profiles were performed on a selection of Protected Designation of Origin (PDO) cheeses representing the four blue-veined cheese categories produced in the Massif Central (Fourme d'Ambert, Fourme de Montbrison, Bleu d'Auvergne and Bleu des Causses). At the same time, physicochemical parameters were measured in these cheeses. The relationship between these two sets of data was investigated. Four types of blue-veined cheeses displayed significantly different behaviour after heating and it is possible to discriminate these cheese categories through specific sensory attributes. Fourme d'Ambert and Bleu d'Auvergne exhibited useful culinary properties: they presented good meltability, stretchability and a weak oiling-off. However, basic tastes (salty, bitter and sour) are also sensory attributes which can distinguish heated blue cheeses. The relationship between the sensory and physicochemical data indicated a correlation suggesting that some of these sensory properties may be explained by certain physicochemical parameters of heated cheeses.
NASA Astrophysics Data System (ADS)
Katata, Lebogang; Tshweu, Lesego; Naidoo, Saloshnee; Kalombo, Lonji; Swai, Hulda
2012-11-01
Efavirenz (EFV) is one of the first-line antiretroviral drugs recommended by the World Health Organisation for treating HIV. It is a hydrophobic drug that suffers from low aqueous solubility (4 μg/mL), which leads to a limited oral absorption and low bioavailability. In order to improve its oral bioavailability, nano-sized polymeric delivery systems are suggested. Spray dried polycaprolactone-efavirenz (PCL-EFV) nanoparticles were prepared by the double emulsion method. The Taguchi method, a statistical design with an L8 orthogonal array, was implemented to optimise the formulation parameters of PCL-EFV nanoparticles. The types of sugar (lactose or trehalose), surfactant concentration and solvent (dichloromethane and ethyl acetate) were chosen as significant parameters affecting the particle size and polydispersity index (PDI). Small nanoparticles with an average particle size of less than 254 ± 0.95 nm in the case of ethyl acetate as organic solvent were obtained as compared to more than 360 ± 19.96 nm for dichloromethane. In this study, the type of solvent and sugar were the most influencing parameters of the particle size and PDI. Taguchi method proved to be a quick, valuable tool in optimising the particle size and PDI of PCL-EFV nanoparticles. The optimised experimental values for the nanoparticle size and PDI were 217 ± 2.48 nm and 0.093 ± 0.02.
Helical CT study of cerebral perfusion and related hemodynamic parameters
NASA Astrophysics Data System (ADS)
Cenic, Aleksa; Lee, Ting-Yim; Craen, Rosemary A.; Gelb, Adrian W.
1997-05-01
A convenient method for assessing cerebral perfusion and related functional parameters has been developed using a third generation slip-ring CT scanner. Dynamic contrast- enhanced scanning at the same level was employed to image the cerebral circulation at the rate of 1 image per second. Using data acquired with this non-helical mode of scanning, we have developed a method for the simultaneous in-vivo determination of cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT). These measurements are given in the same physiological units as positron emission tomography. In order to obtain accurate measurements of these parameters, methods were also developed to correct for recirculation and partial volume averaging in imaging small blood vessels. We have used 6 New Zealand white rabbits in our studies. For each rabbit, up to 3 CT measurements of CBF, CBV, and MTT were made at normocapnia under isoflurane anesthesia. Coronal sections through the brain were imaged while simultaneously imaging either a brain artery or the ear artery. Images were acquired for 1 minute as Isovue 300 was injected intravenously. In the acquired CT images, regions of interest in brain parenchyma and an artery were drawn. For each region of interest, the mean CT number in pre-contrast images was subtracted from the mean in post-contrast images to calculate the contrast concentration curves for the brain regions Q(t) and the arterial region Ca(t). Using a robust deconvolution method, the MTT was determined. CBV was then determined from the ratio of the areas of Q(t) and Ca(t). Finally, CBF was calculated from the Central Volume Principle. The mean regional CBF, CBV and MTT values were 73.3 +/- 5.1 ml/min/100g, 1.93 +/- 0.12 ml/100g and 1.80 +/- 0.18 s respectively. IN order to validate our CT CBF measurements, we also measured CBF using the well- established technique of microspheres with each CT study. The feasibility of our CT method to measure CBF accurately was
NASA Astrophysics Data System (ADS)
Ike, Innocent S.; Sigalas, Iakovos; Iyuke, Sunny E.
2017-01-01
Theoretical expressions for performance parameters of different electrochemical capacitors (ECs) have been optimized by solving them using MATLAB scripts as well as via the MATLAB R2014a optimization toolbox. The performance of the different kinds of ECs under given conditions was compared using theoretical equations and simulations of various models based on the conditions of device components, using optimal values for the coefficient associated with the battery-kind material (K BMopt) and the constant associated with the electrolyte material (K Eopt), as well as our symmetric electric double-layer capacitor (EDLC) experimental data. Estimation of performance parameters was possible based on values for the mass ratio of electrodes, operating potential range ratio, and specific capacitance of electrolyte. The performance of asymmetric ECs with suitable electrode mass and operating potential range ratios using aqueous or organic electrolyte at appropriate operating potential range and specific capacitance was 2.2 and 5.56 times greater, respectively, than for the symmetric EDLC and asymmetric EC using the same aqueous electrolyte, respectively. This enhancement was accompanied by reduced cell mass and volume. Also, the storable and deliverable energies of the asymmetric EC with suitable electrode mass and operating potential range ratios using the proper organic electrolyte were 12.9 times greater than those of the symmetric EDLC using aqueous electrolyte, again with reduced cell mass and volume. The storable energy, energy density, and power density of the asymmetric EDLC with suitable electrode mass and operating potential range ratios using the proper organic electrolyte were 5.56 times higher than for a similar symmetric EDLC using aqueous electrolyte, with cell mass and volume reduced by a factor of 1.77. Also, the asymmetric EDLC with the same type of electrode and suitable electrode mass ratio, working potential range ratio, and proper organic electrolyte
NASA Astrophysics Data System (ADS)
Ike, Innocent S.; Sigalas, Iakovos; Iyuke, Sunny E.
2017-03-01
Theoretical expressions for performance parameters of different electrochemical capacitors (ECs) have been optimized by solving them using MATLAB scripts as well as via the MATLAB R2014a optimization toolbox. The performance of the different kinds of ECs under given conditions was compared using theoretical equations and simulations of various models based on the conditions of device components, using optimal values for the coefficient associated with the battery-kind material ( K BMopt) and the constant associated with the electrolyte material ( K Eopt), as well as our symmetric electric double-layer capacitor (EDLC) experimental data. Estimation of performance parameters was possible based on values for the mass ratio of electrodes, operating potential range ratio, and specific capacitance of electrolyte. The performance of asymmetric ECs with suitable electrode mass and operating potential range ratios using aqueous or organic electrolyte at appropriate operating potential range and specific capacitance was 2.2 and 5.56 times greater, respectively, than for the symmetric EDLC and asymmetric EC using the same aqueous electrolyte, respectively. This enhancement was accompanied by reduced cell mass and volume. Also, the storable and deliverable energies of the asymmetric EC with suitable electrode mass and operating potential range ratios using the proper organic electrolyte were 12.9 times greater than those of the symmetric EDLC using aqueous electrolyte, again with reduced cell mass and volume. The storable energy, energy density, and power density of the asymmetric EDLC with suitable electrode mass and operating potential range ratios using the proper organic electrolyte were 5.56 times higher than for a similar symmetric EDLC using aqueous electrolyte, with cell mass and volume reduced by a factor of 1.77. Also, the asymmetric EDLC with the same type of electrode and suitable electrode mass ratio, working potential range ratio, and proper organic electrolyte
Anaf, Willemien; Trashin, Stanislav; Schalm, Olivier; van Dorp, Dennis; Janssens, Koen; De Wael, Karolien
2014-10-07
Chemical transformations in paintings often induce discolorations, disturbing the appearance of the image. For an appropriate conservation of such valuable and irreplaceable heritage objects, it is important to have a good know-how on the degradation processes of the (historical) materials: which pigments have been discolored, what are the responsible processes, and which (environmental) conditions have the highest impact on the pigment degradation and should be mitigated. Pigment degradation is already widely studied, either by analyzing historical samples or by accelerated weathering experiments on dummies. However, in historic samples several processes may have taken place, increasing the complexity of the current state, while aging experiments are time-consuming due to the often extended aging period. An alternative method is proposed for a fast monitoring of degradation processes of semiconductor pigments, using an electrochemical setup mimicking the real environment and allowing the identification of harmful environmental parameters for each pigment. Examples are given for the pigments cadmium yellow (CdS) and vermilion (α-HgS).
Systematic study of parameters influencing spectral behavior of laboratory mixtures
NASA Astrophysics Data System (ADS)
Mancarella, Francesca; Fonti, Sergio; Alemanno, Giulia; Orofino, Vincenzo; D'Elia, Marcella
2017-04-01
The spectral behavior of mixtures of particulate materials has important implications for the study of planetary surfaces, in particular after that, in the last decades, the spatial resolution of orbiting instruments has improved considerably. In fact, a planetary surface should be considered as composed by mixtures of different minerals and rocks and, in such scenario, a good understanding of the spectral behavior of a mixture, as a function of the characteristics of the components, is necessary for the interpretation of the observational data. In this work, we report the main results of a laboratory test program aimed to check the spectral behavior of several mixtures of particulate samples. The laboratory reflectance spectra are taken in a wide wavelength range from visible (VIS) to mid-infrared (MIR) (i.e. from 0.35 to 25 µm). Then they are carefully analyzed to check how their spectral characteristics are changing as a function of several parameters, such as the mean reflectance level, the percentage and the grain size of the particles of each material.
Studies of Silicon Nanowires with Different Parameters — By PECVD
NASA Astrophysics Data System (ADS)
Leela, S.; Abirami, T.; Bhattacharya, Sekhar; Ahmed, Nafis; Monika, S.; Priya, R. Nivedha
2016-10-01
One-dimensional nanostructures such as nanowires have a wide range of applications. Silicon is the best competitive material for the carbon nanotubes (CNTs). Carbon and silicon have some similar and peculiar properties. Silicon nanowires (SiNWs) were synthesized using plasma enhanced chemical vapor deposition (PECVD) on p-Si (111) wafer. Gold is used as a catalyst for the growth of the SiNWs. Based on our fundamental understanding of vapor-liquid-solid (VLS) nanowire growth mechanism, different levels of growth controls have been achieved. Gold catalyst deposited and annealed at different temperatures with different thicknesses (450∘C, 500∘C and 550∘C, 600∘C, 650∘C for 4min and 8min and 3nm, 5nm, 30nm Au thickness). SiNW grown by PECVD with different carrier gases varies with flow rate. We observed the different dimensions of Si nanowires by FESEM and optimized the growth parameters to get the vertical aligned and singular Si nanowires. Optical phonon of the Si nanowires and crystallinity nature were identified by Raman spectral studies.
The little-studied cluster Berkeley 90 - III. Cluster parameters
NASA Astrophysics Data System (ADS)
Marco, Amparo; Negueruela, Ignacio
2017-02-01
The open cluster Berkeley 90 is the home to one of the most massive binary systems in the Galaxy, LS III +46°11, formed by two identical, very massive stars (O3.5 If* + O3.5 If*), and a second early-O system (LS III +46°12 with an O4.5 IV((f)) component at least). Stars with spectral types earlier than O4 are very scarce in the Milky Way, with no more than 20 examples. The formation of such massive stars is still an open question today, and thus the study of the environments where the most massive stars are found can shed some light on this topic. To this aim, we determine the properties and characterize the population of Berkeley 90 using optical, near-infrared and WISE photometry and optical spectroscopy. This is the first determination of these parameters with accuracy. We find a distance of 3.5^{+0.5}_{-0.5} kpc and a maximum age of 3 Ma. The cluster mass is around 1000 M⊙ (perhaps reaching 1500 M⊙ if the surrounding population is added), and we do not detect candidate runaway stars in the area. There is a second population of young stars to the southeast of the cluster that may have formed at the same time or slightly later, with some evidence for low-activity ongoing star formation.
Simulation Study on the Controllable Dielectrophoresis Parameters of Graphene
NASA Astrophysics Data System (ADS)
Ji, Jian-Long; Liu, Ya-Li; Ge, Yang; Xie, Sheng-Dong; Zhang, Xi; Sang, Sheng-Bo; Jian, Ao-Qun; Duan, Qian-Qian; Zhang, Qiang; Zhang, Wen-Dong
2017-03-01
The method of using dielectrophoresis (DEP) to assemble graphene between micro-electrodes has been proven to be simple and efficient. We present an optimization method for the kinetic formula of graphene DEP, and discuss the simulation of the graphene assembly process based on the finite element method. The simulated results illustrate that the accelerated motion of graphene is in agreement with the distribution of the electric field squared gradient. We also conduct research on the controllable parameters of the DEP assembly such as the alternating current (AC) frequency, the shape of micro-electrodes, and the ratio of the gap between electrodes to the characteristic/geometric length of graphene (λ). The simulations based on the Clausius-Mossotti factor reveal that both graphene velocity and direction are influenced by the AC frequency. When graphene is close to the electrodes, the shape of micro-electrodes will exert great influence on the velocity of graphene. Also, λ has a great influence on the velocity of graphene. Generally, the velocity of graphene would be greater when λ is in the range of 0.4-0.6. The study is of a theoretical guiding significance in improving the precision and efficiency of the graphene DEP assembly. Supported by the Basic Research Project of Shanxi Province under Grant No 2015021092, the National Natural Science Foundation of China under Grant Nos 61471255, 61474079, 61501316, 51505324 and 51622507, and the National High-Technology Research and Development Program of China under Grant No 2015AA042601.
Parameter Trade Studies For Coherent Lidar Wind Measurements of Wind from Space
NASA Technical Reports Server (NTRS)
Kavaya, Michael J.; Frehlich, Rod G.
2007-01-01
The design of an orbiting wind profiling lidar requires selection of dozens of lidar, measurement scenario, and mission geometry parameters; in addition to prediction of atmospheric parameters. Typical mission designs do not include a thorough trade optimization of all of these parameters. We report here the integration of a recently published parameterization of coherent lidar wind velocity measurement performance with an orbiting coherent wind lidar computer simulation; and the use of these combined tools to perform some preliminary parameter trades. We use the 2006 NASA Global Wind Observing Sounder mission design as the starting point for the trades.
Lazaris, Charalampos; Kelly, Stephen; Ntziachristos, Panagiotis; Aifantis, Iannis; Tsirigos, Aristotelis
2017-01-05
Chromatin conformation capture techniques have evolved rapidly over the last few years and have provided new insights into genome organization at an unprecedented resolution. Analysis of Hi-C data is complex and computationally intensive involving multiple tasks and requiring robust quality assessment. This has led to the development of several tools and methods for processing Hi-C data. However, most of the existing tools do not cover all aspects of the analysis and only offer few quality assessment options. Additionally, availability of a multitude of tools makes scientists wonder how these tools and associated parameters can be optimally used, and how potential discrepancies can be interpreted and resolved. Most importantly, investigators need to be ensured that slight changes in parameters and/or methods do not affect the conclusions of their studies. To address these issues (compare, explore and reproduce), we introduce HiC-bench, a configurable computational platform for comprehensive and reproducible analysis of Hi-C sequencing data. HiC-bench performs all common Hi-C analysis tasks, such as alignment, filtering, contact matrix generation and normalization, identification of topological domains, scoring and annotation of specific interactions using both published tools and our own. We have also embedded various tasks that perform quality assessment and visualization. HiC-bench is implemented as a data flow platform with an emphasis on analysis reproducibility. Additionally, the user can readily perform parameter exploration and comparison of different tools in a combinatorial manner that takes into account all desired parameter settings in each pipeline task. This unique feature facilitates the design and execution of complex benchmark studies that may involve combinations of multiple tool/parameter choices in each step of the analysis. To demonstrate the usefulness of our platform, we performed a comprehensive benchmark of existing and new TAD callers
Parameter studies of sediments in the Storegga Slide region
NASA Astrophysics Data System (ADS)
Yang, S. L.; Kvalstad, T.; Solheim, A.; Forsberg, C. F.
2006-09-01
Based on classification tests, oedometer tests, fall-cone tests and triaxial tests, physical and mechanical properties of sediments in the Storegga Slide region were analysed to assess parameter interrelationships. The data show good relationships between a number of physical and mechanical parameters. Goodness of fit between compression index and various physical parameters can be improved by multiple regression analysis. The interclay void ratio and liquidity index correlate well with the undrained shear strength of clay. Sediments with higher water content, liquid limit, activity, interclay void ratio, plasticity index and liquidity index showed higher compression index and/or lower undrained shear strength. Some relationships between parameters were tested by using data from two other sites south of the Storegga Slide. A better understanding of properties of sediments in regions such as that of the Storegga Slide can be obtained through this approach.
Sherwin, Catherine M T; Ngamprasertwong, Pornswan; Sadhasivam, Senthilkumar; Vinks, Alexander A
2014-02-01
Multiple blood samples are generally required for measurement of pharmacokinetic (PK) parameters. D-optimal design is a popular and frequently used approach for determination of sampling time points in order to minimize the number of samples, while optimizing the estimation of PK parameters. Optimal design utilizing ADAPT (v5, BSR, University of Southern California, Los Angeles) developed a sparse sampling strategy to determine measurement of propofol in pregnant sheep. Propofal was administered as supplemental anesthetic agent to inhalation anesthesia to mimic anesthesia for open fetal surgery. In our preliminary study, propofol 3 mg/kg was given as a bolus to the ewe, followed by propofol infusion at rate 450 mcg/kg/min for 60 minutes, then decreased to 75 mcg/kg/min for 90 more minutes and then ceased. A three compartment model described the PK parameters with the fetus assumed as the third compartment. Initially, sampling times were chosen from thirteen time points as previously stated in the literature. Using priori propofol PK estimates, the final 9 sample time points were proposed in an optimal design with a change in infusion rate occurring between 65 and 75 minutes and sampling proposed at 5, 15, 25, 65, 75, 100, 110, 150, and 180 minutes. D-optimal design optimized the number and timing of samplings, which led to a reduction of cost and man power in the study protocol while preserving the ability to estimate propofol PK parameters in the maternal and fetal sheep model. Initial evaluation of samples collected from three sheep using the optimal design strategy confirmed the performance of the design in obtaining effective PK parameter estimates.
Sherwin, Catherine M. T.; Ngamprasertwong, Pornswan; Sadhasivam, Senthilkumar; Vinks, Alexander A.
2017-01-01
Multiple blood samples are generally required for measurement of pharmacokinetic (PK) parameters. D-optimal design is a popular and frequently used approach for determination of sampling time points in order to minimize the number of samples, while optimizing the estimation of PK parameters. Optimal design utilizing ADAPT (v5, BSR, University of Southern California, Los Angeles) developed a sparse sampling strategy to determine measurement of propofol in pregnant sheep. Propofal was administered as supplemental anesthetic agent to inhalation anesthesia to mimic anesthesia for open fetal surgery. In our preliminary study, propofol 3 mg/kg was given as a bolus to the ewe, followed by propofol infusion at rate 450 mcg/kg/min for 60 minutes, then decreased to 75 mcg/kg/min for 90 more minutes and then ceased. A three compartment model described the PK parameters with the fetus assumed as the third compartment. Initially, sampling times were chosen from thirteen time points as previously stated in the literature. Using priori propofol PK estimates, the final 9 sample time points were proposed in an optimal design with a change in infusion rate occurring between 65 and 75 minutes and sampling proposed at 5, 15, 25, 65, 75, 100, 110, 150, and 180 minutes. D-optimal design optimized the number and timing of samplings, which led to a reduction of cost and man power in the study protocol while preserving the ability to estimate propofol PK parameters in the maternal and fetal sheep model. Initial evaluation of samples collected from three sheep using the optimal design strategy confirmed the performance of the design in obtaining effective PK parameter estimates. PMID:24219004
NASA Astrophysics Data System (ADS)
Karimi Movahed, Kamran; Zhang, Zhi-Hai
2015-09-01
Demand and lead time uncertainties have significant effects on supply chain behaviour. In this paper, we present a single-product three-level multi-period supply chain with uncertain demands and lead times by using robust techniques to study the managerial insights of the supply chain inventory system under uncertainty. We formulate this problem as a robust mixed-integer linear program with minimised expected cost and total cost variation to determine the optimal (s, S) values of the inventory parameters. Several numerical studies are performed to investigate the supply chain behaviour. Useful guidelines for the design of a robust supply chain are also provided. Results show that the order variance and the expected cost in a supply chain significantly increase when the manufacturer's review period is an integer ratio of the distributor's and the retailer's review periods.
[The Study of Advanced Fundamental Parameter Method in EDXRFA].
Cheng, Feng; Zhang, Qing-xian; Ge, Liang-quan; Gu, Yi; Zeng, Guo-qiang; Luo, Yao-yao; Chen, Shuang; Wang, Lei; Zhao, Jian-kun
2015-07-01
The X-ray Fluorescence Analysis(XRFA) is an important and efficient method on the element anylsis and is used in geology, industry and environment protection. But XRFA has a backdraw that the determination limit and accuracy are effected by the matrix of the sample. Now the fundamental parameter is usually used to calculate the content of elements in XRFA, and it is an efficient method if the matrix and net area of characteristic X-ray peak are obtained. But this is invalide in in-stu XRFA. Also the method of net area and the "black material" of sample are the key point of the fundamental parameter method when the Energy Dispersive X-ray Fluorescence Analysis(EDXRFA) method is used in the low content sample. In this paper a advanced fundamental parameter method is discussed. The advanced fundamental parameter method includes the spectra analysis and the fundamental parameter method, which inserts the overlapping peaks separation method into the iteration process of the fundamental parameter method. The advanced method can resolve the net area and the quantitative analysis. The advanced method is used to analyse the standard sample. Compare to the content obtained from the coefficient method, the precision of Cu, Ni and Zn is better than coeffieciency method. The result shows that the advanced method could improve the precision of the EDXRFA, so the advanced method is better than the coefficient method.
A less field-intensive robust design for estimating demographic parameters with Mark-resight data
McClintock, B.T.; White, Gary C.
2009-01-01
The robust design has become popular among animal ecologists as a means for estimating population abundance and related demographic parameters with mark-recapture data. However, two drawbacks of traditional mark-recapture are financial cost and repeated disturbance to animals. Mark-resight methodology may in many circumstances be a less expensive and less invasive alternative to mark-recapture, but the models developed to date for these data have overwhelmingly concentrated only on the estimation of abundance. Here we introduce a mark-resight model analogous to that used in mark-recapture for the simultaneous estimation of abundance, apparent survival, and transition probabilities between observable and unobservable states. The model may be implemented using standard statistical computing software, but it has also been incorporated into the freeware package Program MARK. We illustrate the use of our model with mainland New Zealand Robin (Petroica australis) data collected to ascertain whether this methodology may be a reliable alternative for monitoring endangered populations of a closely related species inhabiting the Chatham Islands. We found this method to be a viable alternative to traditional mark-recapture when cost or disturbance to species is of particular concern in long-term population monitoring programs. ?? 2009 by the Ecological Society of America.
Katsoni, Athanasia; Frontistis, Zaharias; Xekoukoulotakis, Nikolaos P; Diamadopoulos, Evan; Mantzavinos, Dionissios
2008-08-01
The wet air oxidation of an effluent from edible olive processing was investigated. Semibatch experiments were conducted with 0.3L of effluent loaded into an autoclave and pure oxygen fed continuously to maintain an oxygen partial pressure of 2.5MPa. The effect of operating conditions, such as initial organic loading (from 1240 to 5150mg/L COD), reaction time (from 30 to 120min), temperature (from 140 to 180 degrees C), initial pH (from 3 to 7) and the use of 500mg/L H(2)O(2) as an additional oxidant, on treatment efficiency was assessed implementing a factorial experimental design. All five parameters had a statistically considerable effect on COD removal, alongside second order interactions of COD with reaction temperature, contact time and effluent pH. In most cases, high levels of phenols degradation (up to 100%) and decolorization (up to 90%) were achieved followed by low to moderate mineralization (up to 70%). The oxidation of phenols was affected to a considerable level by the initial COD, reaction temperature and contact time, as well as the second order interaction between COD and temperature, while all other effects were insignificant.
NASA Astrophysics Data System (ADS)
Lucas, Yves; Domingues, Antonio; Driouchi, Driss; Treuillet, Sylvie
2006-12-01
Tuning a complete image processing chain (IPC) is not a straightforward task. The first problem to overcome is the evaluation of the whole process. Until now researchers have focused on the evaluation of single algorithms based on a small number of test images and ad hoc tuning independent of input data. In this paper, we explain how the design of experiments applied on a large image database enables statistical modeling for IPC significant parameter identification. The second problem is then considered: how can we find the relevant tuning and continuously adapt image processing to input data? After the tuning of the IPC on a typical subset of the image database using numerical optimization, we develop an adaptive IPC based on a neural network working on input image descriptors. By testing this approach on an IPC dedicated-to-road obstacle detection, we demonstrate that this experimental methodology and software architecture can ensure continuous efficiency. The reason is simple: the IPC is globally optimized, from a large number of real images and with adaptive processing of input data.
Impact of the Cooling Equipment on the Key Design Parameters of a Core-Form Power Transformer
NASA Astrophysics Data System (ADS)
Orosz, Tamás; Tamus, Zoltán Ádám
2016-12-01
The first step in the transformer design process is to find the active part's key design parameters. This is a non-linear mathematical optimisation task, which becomes more complex if the economic conditions are considered by the capitalisation of the losses. Geometric programming combined with the method of branch and bound can be an effective and accurate tool for this task even in the case of core-form power transformers, when formulating the short-circuit impedance in the required form is problematic. Most of the preliminary design methods consider only the active part of the transformer and the capitalised costs in order to determine the optimal key design parameters. In this paper, an extension of this meta-heuristic transformer optimisation model, which takes the cost of the insulating oil and the cooling equipment into consideration, is presented. Moreover, the impact of the new variables on the optimal key design parameters of a transformer design is examined and compared with the previous algorithm in two different economic scenarios. Significant difference can be found between the optimal set of key-design parameters if these new factors are considered.
Crespi, Catherine M; Wong, Weng Kee; Wu, Sheng
2011-12-01
Power and sample size calculations for cluster randomized trials require prediction of the degree of correlation that will be realized among outcomes of participants in the same cluster. This correlation is typically quantified as the intraclass correlation coefficient (ICC), defined as the Pearson correlation between two members of the same cluster or proportion of the total variance attributable to variance between clusters. It is widely known but perhaps not fully appreciated that for binary outcomes, the ICC is a function of outcome prevalence. Hence, the ICC and the outcome prevalence are intrinsically related, making the ICC poorly generalizable across study conditions and between studies with different outcome prevalences. We use a simple parametrization of the ICC that aims to isolate that part of the ICC that measures dependence among responses within a cluster from the outcome prevalence. We incorporate this parametrization into sample size calculations for cluster randomized trials and compare our method to the traditional approach using the ICC. Our dependence parameter, R, may be less influenced by outcome prevalence and has an intuitive meaning that facilitates interpretation. Estimates of R from previous studies can be obtained using simple statistics. Comparison of methods showed that the traditional ICC approach to sample size determination tends to overpower studies under many scenarios, calling for more clusters than truly required. The methods are developed for equal-sized clusters, whereas cluster size may vary in practice. The dependence parameter R is an alternative measure of dependence among binary outcomes in cluster randomized trials that has a number of advantages over the ICC.
Active Remote Sensing of Ocean Parameters, AN Engineering Study.
NASA Astrophysics Data System (ADS)
Byrne, James Dennis
A study is made of a proposed method to measure the sound velocity, turbidity, and calculate the temperature as a function of depth in the ocean. A laser is used to generate a beam of light which is scattered by the sea. Brillouin scattering causes shifts of the wavelength of the incident laser light by an amount proportional to the sound velocity in the sea. Several instrumental designs for measuring this shift are considered. Fabry-Perot interferometers were chosen for use in prototype instruments. Initial laboratory experiments are described. A field experiment with a single Fabry-Perot used photographically and photoelectrically is described. This field experiment achieved what we believe to be the first measurement of the Brillouin effect in seawater under field conditions. A new double Fabry-Perot instrument was designed which could be adapted to a lidar system. If a value for the salinity is assumed, the instrument can be used to determine temperature. The performance of this system as a temperature transducer was tested in the laboratory. Using ten second observations temperature was measured with an rms estimate of error of 0.4(DEGREES)C in fresh water. Sound velocity measurement accuracy is estimated at better than 0.1% m/sec over the range of temperatures which were measured. Using modern interferometers and a more powerful laser this result could be greatly improved. Recommendations and cost estimates for a future instrument are included. Auxiliary methods which could allow the unambiguous computation of temperature and salinity from sound velocity data are discussed in Appendix one.
NASA Astrophysics Data System (ADS)
Gopalakrishnan, T.; Saravanan, R.
2017-03-01
Powerful management concepts step-up the quality of the product, time saving in producing the product thereby increase the production rate, improves tools and techniques, work culture, work place and employee motivation and morale. In this paper discussed about the case study of optimizing the tool design, tool parameters to cast off expansion plan according ECRS technique. The proposed designs and optimal tool parameters yielded best results and meet the customer demand without expansion plan. Hence the work yielded huge savings of money (direct and indirect cost), time and improved the motivation and more of employees significantly.