Closed-form solution of decomposable stochastic models
NASA Technical Reports Server (NTRS)
Sjogren, Jon A.
1992-01-01
Equations to compute failure probabilities of the total (combined) model without a complete solution of the combined model are presented. A closed-form analytical approach to presentation of probabilities is used on the bases of the Symbolic Hierarchical Automated Reliability and Performance Evaluator tool. The techniques under consideration make it possible to compute the probability function for a much wider class of systems at a reduced computational cost.
Closed-form solution of decomposable stochastic models
NASA Technical Reports Server (NTRS)
Sjogren, Jon A.
1990-01-01
Markov and semi-Markov processes are increasingly being used in the modeling of complex reconfigurable systems (fault tolerant computers). The estimation of the reliability (or some measure of performance) of the system reduces to solving the process for its state probabilities. Such a model may exhibit numerous states and complicated transition distributions, contributing to an expensive and numerically delicate solution procedure. Thus, when a system exhibits a decomposition property, either structurally (autonomous subsystems), or behaviorally (component failure versus reconfiguration), it is desirable to exploit this decomposition in the reliability calculation. In interesting cases there can be failure states which arise from non-failure states of the subsystems. Equations are presented which allow the computation of failure probabilities of the total (combined) model without requiring a complete solution of the combined model. This material is presented within the context of closed-form functional representation of probabilities as utilized in the Symbolic Hierarchical Automated Reliability and Performance Evaluator (SHARPE) tool. The techniques adopted enable one to compute such probability functions for a much wider class of systems at a reduced computational cost. Several examples show how the method is used, especially in enhancing the versatility of the SHARPE tool.
Idealized Closed Form Performance Modeling of a Closed Cycle Joule-Thomson Cryocooler
NASA Astrophysics Data System (ADS)
Maytal, B.-Z.
2004-06-01
The characteristic parameters of a closed cycle Joule-Thomson cryocooler would be: the charging pressure, discharge and suction volumes of the loop, volumetric displacement of the compressor and the extent of throttling restriction. A series of idealizing assumption are applied. The volumetric behavior of the coolant is assumed to obey the ideal gas equation. The recuperator and compressor's volumetric delivery are completely efficient. There are no pressure losses along the circulating path. On this basis is developed a closed form model of the system, interrelating the relevant parameters. Performance at steady state is expressed in terms of the circulating flow rate, discharge and suction pressures and cooling power. The model predicts the optimal size of equivalent orifice and the maximized cooling power. Also derived is the hydrodynamic time constant of building up the discharge pressure. This analysis is relevant for mixed coolants as well as for pure coolants closed cycles. The former typically employ lower pressure and therefore the idealized assumptions are even more applicable.
12 CFR Appendix H to Part 1026 - Closed-End Model Forms and Clauses
Code of Federal Regulations, 2014 CFR
2014-01-01
... 12 Banks and Banking 9 2014-01-01 2014-01-01 false Closed-End Model Forms and Clauses H Appendix H to Part 1026 Banks and Banking BUREAU OF CONSUMER FINANCIAL PROTECTION TRUTH IN LENDING (REGULATION Z) Pt. 1026, App. H Appendix H to Part 1026—Closed-End Model Forms and Clauses H-1Credit Sale Model Form (§ 1026.18) H-2Loan Model Form (§ 1026.18)...
Validation of closed-form compression noise statistics using model observers
NASA Astrophysics Data System (ADS)
Li, Dunling; Loew, Murray
2007-03-01
Model observers have been used successfully to predict human observer performance and to evaluate image quality for detection tasks on various backgrounds in medical applications. This paper will apply the closed-form compression noise statistics in analytic form to model observers and the derived channelized Hotelling observer (CHO) for decompressed images. The performance of CHO on decompressed images is validated using JPEG compression algorithm and lumpy background images. The results show that the derived CHO performance predicts closely its simulated performance.
12 CFR Appendix H to Part 226 - Closed-End Model Forms and Clauses
Code of Federal Regulations, 2011 CFR
2011-01-01
... Clauses (§ 226.20(c)) H-4(E)—Fixed-Rate Mortgage Interest Rate and Payment Summary Model Clause (§ 226.18... 12 Banks and Banking 3 2011-01-01 2011-01-01 false Closed-End Model Forms and Clauses H Appendix H... RESERVE SYSTEM TRUTH IN LENDING (REGULATION Z) Pt. 226, App. H Appendix H to Part 226— Closed-End...
Closed-form solutions of performability. [modeling of a degradable buffer/multiprocessor system
NASA Technical Reports Server (NTRS)
Meyer, J. F.
1981-01-01
Methods which yield closed form performability solutions for continuous valued variables are developed. The models are similar to those employed in performance modeling (i.e., Markovian queueing models) but are extended so as to account for variations in structure due to faults. In particular, the modeling of a degradable buffer/multiprocessor system is considered whose performance Y is the (normalized) average throughput rate realized during a bounded interval of time. To avoid known difficulties associated with exact transient solutions, an approximate decomposition of the model is employed permitting certain submodels to be solved in equilibrium. These solutions are then incorporated in a model with fewer transient states and by solving the latter, a closed form solution of the system's performability is obtained. In conclusion, some applications of this solution are discussed and illustrated, including an example of design optimization.
A simple, closed-form, mathematical model for gas exchange in microchannel artificial lungs.
Potkay, Joseph A
2013-06-01
Microfabrication techniques are attractive for constructing artificial lungs due to the ability to create features similar in size to those in the natural lung. However, a simple and intuitive mathematical model capable of accurately predicting the gas exchange performance of microchannel artificial lungs does not currently exist. Such a model is critical to understanding and optimizing these devices. Here, we describe a simple, closed-form mathematical model for gas exchange in microchannel artificial lungs and qualify it through application to experimental data from several research groups. We utilize lumped parameters and several assumptions to obtain a closed-form set of equations that describe gas exchange. This work is intended to augment computational models by providing a more intuitive, albeit potentially less accurate, understanding of the operation and trade-offs inherent in microchannel artificial lung devices.
Closed-form solution of the Ogden-Hill's compressible hyperelastic model for ramp loading
NASA Astrophysics Data System (ADS)
Berezvai, Szabolcs; Kossa, Attila
2016-09-01
This article deals with the visco-hyperelastic modelling approach for compressible polymer foam materials. Polymer foams can exhibit large elastic strains and displacements in case of volumetric compression. In addition, they often show significant rate-dependent properties. This material behaviour can be accurately modelled using the visco-hyperelastic approach, in which the large strain viscoelastic description is combined with the rate-independent hyperelastic material model. In case of polymer foams, the most widely used compressible hyperelastic material model, the so-called Ogden-Hill's model, was applied, which is implemented in the commercial finite element (FE) software uc(Abaqus). The visco-hyperelastic model is defined in hereditary integral form, therefore, obtaining a closed-form solution for the stress is not a trivial task. However, the parameter-fitting procedure could be much faster and accurate if closed-form solution exists. In this contribution, exact stress solutions are derived in case of uniaxial, biaxial and volumetric compression loading cases using ramp-loading history. The analytical stress solutions are compared with the stress results in uc(Abaqus) using FE analysis. In order to highlight the benefits of the analytical closed-form solution during the parameter-fitting process experimental work has been carried out on a particular open-cell memory foam material. The results of the material identification process shows significant accuracy improvement in the fitting procedure by applying the derived analytical solutions compared to the so-called separated approach applied in the engineering practice.
NASA Astrophysics Data System (ADS)
Javadzadeh, S. Mohammad Hassan; Mamaghany, Zahra Mardy; Farzaneh, Forouhar; Fardmanesh, Mehdi
A distributed circuit model for different kinds of discontinuities in high temperature superconducting (HTS) microstrip transmission lines (TLs), is proposed. In each case, closed form formula for lumped element model is presented based on the configuration of the discontinuity and the characterizations of HTS microstrip TLs. These discontinuities consist of steps in width, open ends, gaps and 90-degree bends. In the case of normal conductor microstrip TLs there are a lot of numerical and analytical equations that can accurately model them, however those formulas are not efficient for HTS TLs. Thus modified relations are extracted utilizing the superconducting characterizations to obtain much more accurate formulas. Additionally temperature dependence of HTS TLs is considered in the relations. Moreover regarding the kinetic inductance in HTS TLs a closed form formula is proposed for characteristic impedance of HTS TLs. Furthermore correction factors based on fringe fields is used to optimize all formulas. Using these formulations can lead to modeling and analysis of some superconducting microwave devices such as resonators, microwave filters, couplers, etc. In contrast to EM analysis, using the distributed circuit model is much easier for analysis of HTS microwave devices. The accuracy of the proposed model is confirmed in comparison with some electromagnetic full-wave simulations. This full analytical approach shows great accuracy in this test case as well.
Fowler, Patrick W; Myrvold, Wendy
2011-11-17
Conjugated-circuit models for induced π ring currents differ in the types of circuit that they include and the weights attached to them. Choice of circuits for general π systems can be expressed compactly in terms of matchings of the circuit-deleted molecular graph. Variants of the conjugated-circuit model for induced π currents are shown to have simple closed-form solutions for linear polyacenes. Despite differing assumptions about the effect of cycle area, all the models predict the most intense perimeter current in the central rings, in general agreement with ab initio current-density maps. All tend to overestimate the rate of increase with N of the central ring current for the [N]polyacene, in comparison with molecular-orbital treatments using ipsocentric ab initio, pseudo-π, and Hückel-London approaches.
Kubo-equivalent closed-form graphene conductivity models (Conference Presentation)
NASA Astrophysics Data System (ADS)
Kudyshev, Zhaxylyk A.; Prokopeva, Ludmila J.; Kildishev, Alexander V.
2016-09-01
The optical response of graphene is described by its surface conductivity - a multivariate function of frequency, temperature, chemical potential, and scattering rate. A Kubo formula that accounts for both interband and intraband transitions with two Fermi-Dirac-like integrals is conventionally used to model graphene. The first (intraband) integral can be reduced analytically to a Drude term. The second (intraband) term requires computationally expensive numerical integration over the infinite range of energies, and thus it is usually either neglected or substituted with a simpler approximation (typically valid within a limited range of parameters). Additional challenge is an integral-free time-domain (TD) formulation that would allow efficient coupling of the interband conductivity term to TD electromagnetic solvers. We propose Kubo-equivalent models of graphene surface conductivity that offer closed-form computationally efficient representations in time and frequency domains. We show that in time domain Kubo's formula reduces to a combination of rational, trigonometric, hyperbolic, and exponential functions. In frequency domain the integral term is equivalent to an expression with digamma and incomplete gamma functions. The accuracy and improved performance of our integral-free formulations versus the direct integration of Kubo's formula is critically analyzed. The result provides efficient broadband multivariate coupling of graphene dispersion to time-domain and frequency-domain solvers. To reinforce theory with practical examples, we use obtained closed-form frequency-domain model to retrieve the optical properties of graphene samples from variable angle spectroscopic ellipsometry (VASE) measurements. . We present ellipsometry fitting cases that are built on an in-the-cloud tool freely available online (https://nanohub.org/resources/photonicvasefit).
A mass weighted chemical elastic network model elucidates closed form domain motions in proteins
Kim, Min Hyeok; Seo, Sangjae; Jeong, Jay Il; Kim, Bum Joon; Liu, Wing Kam; Lim, Byeong Soo; Choi, Jae Boong; Kim, Moon Ki
2013-01-01
An elastic network model (ENM), usually Cα coarse-grained one, has been widely used to study protein dynamics as an alternative to classical molecular dynamics simulation. This simple approach dramatically saves the computational cost, but sometimes fails to describe a feasible conformational change due to unrealistically excessive spring connections. To overcome this limitation, we propose a mass-weighted chemical elastic network model (MWCENM) in which the total mass of each residue is assumed to be concentrated on the representative alpha carbon atom and various stiffness values are precisely assigned according to the types of chemical interactions. We test MWCENM on several well-known proteins of which both closed and open conformations are available as well as three α-helix rich proteins. Their normal mode analysis reveals that MWCENM not only generates more plausible conformational changes, especially for closed forms of proteins, but also preserves protein secondary structures thus distinguishing MWCENM from traditional ENMs. In addition, MWCENM also reduces computational burden by using a more sparse stiffness matrix. PMID:23456820
An explicit closed-form analytical solution for European options under the CGMY model
NASA Astrophysics Data System (ADS)
Chen, Wenting; Du, Meiyu; Xu, Xiang
2017-01-01
In this paper, we consider the analytical pricing of European path-independent options under the CGMY model, which is a particular type of pure jump Le´vy process, and agrees well with many observed properties of the real market data by allowing the diffusions and jumps to have both finite and infinite activity and variation. It is shown that, under this model, the option price is governed by a fractional partial differential equation (FPDE) with both the left-side and right-side spatial-fractional derivatives. In comparison to derivatives of integer order, fractional derivatives at a point not only involve properties of the function at that particular point, but also the information of the function in a certain subset of the entire domain of definition. This "globalness" of the fractional derivatives has added an additional degree of difficulty when either analytical methods or numerical solutions are attempted. Albeit difficult, we still have managed to derive an explicit closed-form analytical solution for European options under the CGMY model. Based on our solution, the asymptotic behaviors of the option price and the put-call parity under the CGMY model are further discussed. Practically, a reliable numerical evaluation technique for the current formula is proposed. With the numerical results, some analyses of impacts of four key parameters of the CGMY model on European option prices are also provided.
Closed-form modelling and design analysis of V- and Z-shaped electrothermal microactuators
NASA Astrophysics Data System (ADS)
Zhang, Zhuo; Zhang, Weize; Wu, Qiyang; Yu, Yueqing; Liu, Xinyu; Zhang, Xuping
2017-01-01
This paper presents the modelling and design analysis of V- and Z-shaped electrothermal microactuators. First, a comprehensive but concise closed-form multiphysical analytical model is developed to predict the output displacement and force of both V- and Z-shaped electrothermal microactuators operating either in vacuum or in air conditions. The analytical model is verified by finite element analysis and experimental testing. Then, a novel comparison benchmark is proposed for the design and analysis of the V- and Z-shaped microactuators. With the multiphysical model and comparison benchmark, comprehensive performance comparison and analysis of the V- and Z-shaped beams are performed with the aim of providing insight and guidance on selection and design of the two typical types of electrothermal microactuators. Finally, the application of the comparison model into the design analysis is demonstrated using a design example of an electrothermal microactuator, and the detailed investigation is conducted to examine the effects of the material properties and structural parameters on the microactuator outputs.
12 CFR Appendix H to Part 226 - Closed-End Model Forms and Clauses
Code of Federal Regulations, 2010 CFR
2010-01-01
... RESERVE SYSTEM TRUTH IN LENDING (REGULATION Z) Pt. 226, App. H Appendix H to Part 226—Closed-End Model... new Truth in Lending disclosures; or (3) the date you received this notice of your right to cancel....
Closed form flow model of a damped slug test in a fractured bedrock borehole
NASA Astrophysics Data System (ADS)
Ostendorf, David W.; Lukas, William G.; Hinlein, Erich S.
2015-10-01
An existing closed form model is modified to describe the damped response of groundwater in a fractured bedrock borehole with variable apertures and dips to a slug test. The existing theory, which requires single sized horizontal fractures, is accurately calibrated by slug test data from three uncased bedrock boreholes in the Dedham Granite and an observation well screened just below the contact surface with a till drumlin. Apertures and dips vary however, so the ability of the modified theory to accommodate different sizes and inclinations improves upon the physical validity of its predecessor when fracture information accompanies slug test data. Geophysical logs identify a large number and dip of fractures in the uncased boreholes in the Dedham Granite in this regard. A lognormally distributed, horizontal aperture calibration of the slug tests in the uncased boreholes retains the accuracy of the single size model, and yields aperture statistics more consistent with literature values. The slug test in the screened observation well is accurately calibrated with the modified horizontal theory for discrete (two) sizes, based upon the average fracture spacing found in the uncased boreholes. All four results yield comparable compressibility estimates, which depend on fracture spacing but not size or dip. The calibrated aperture size and calculated fracture porosity and permeability decrease with length of the borehole into the Dedham Granite. The measured dip and aperture for flowing and nonflowing fractures in one of the boreholes accurately calibrates the modified theory. The inclusion of dip reduces the calibrated permeability because of the increased ellipsoidal area at the interface of the borehole and the inclined fractures.
A model for closing the inviscid form of the average passage equation system
NASA Technical Reports Server (NTRS)
Adamczyk, John J.; Mulac, R. A.; Celestina, M. L.
1996-01-01
A mathematical model for closing or mathematically completing the system of equations is proposed. The model describes the time average flow field through the blade passages of multistage turbomachinery. These average-passage equation systems govern a conceptual model useful in turbomachinery aerodynamic design and analysis. The closure model was developed to insure a consistency between these equations and the axisymmetric through-flow equations. The closure model was incorporated into a calculation code for use in the simulation of the flow field about a high-speed counter rotating propeller and a high-speed fan stage.
A model for closing the inviscid form of the average-passage equation system
NASA Technical Reports Server (NTRS)
Adamczyk, J. J.; Mulac, R. A.; Celestina, M. L.
1985-01-01
A mathematical model is proposed for closing or mathematically completing the system of equations which describes the time average flow field through the blade passages of multistage turbomachinery. These equations referred to as the average passage equation system govern a conceptual model which has proven useful in turbomachinery aerodynamic design and analysis. The closure model is developed so as to insure a consistency between these equations and the axisymmetric through flow equations. The closure model was incorporated into a computer code for use in simulating the flow field about a high speed counter rotating propeller and a high speed fan stage. Results from these simulations are presented.
A model for closing the inviscid form of the average-passage equation system
NASA Technical Reports Server (NTRS)
Adamczyk, J. J.; Mulac, R. A.; Celestina, M. L.
1986-01-01
A mathematical model is proposed for closing or mathematically completing the system of equations which describes the time average flow field through the blade passages of multistage turbomachinery. These equations referred to as the average passage equation system govern a conceptual model which has proven useful in turbomachinery aerodynamic design and analysis. The closure model is developed so as to insure a consistency between these equations and the axisymmetric through flow equations. The closure model was incorporated into a computer code for use in simulating the flow field about a high speed counter rotating propeller and a high speed fan stage. Results from these simulations are presented.
A model of the closed form of the nicotinic acetylcholine receptor m2 channel pore.
Kim, Sanguk; Chamberlain, Aaron K; Bowie, James U
2004-08-01
The nicotinic acetylcholine receptor is a neurotransmitter-gated ion channel in the postsynaptic membrane. It is composed of five homologous subunits, each of which contributes one transmembrane helix--the M2 helix--to create the channel pore. The M2 helix from the delta subunit is capable of forming a channel by itself. Although a model of the receptor was recently proposed based on a low-resolution, cryo-electron microscopy density map, we found that the model does not explain much of the other available experimental data. Here we propose a new model of the M2 channel derived solely from helix packing and symmetry constraints. This model agrees well with experimental results from solid-state NMR, chemical reactivity, and mutagenesis experiments. The model depicts the channel pore, the channel gate, and the residues responsible for cation specificity.
NASA Astrophysics Data System (ADS)
Lemmens, D.; Wouters, M.; Tempere, J.; Foulon, S.
2008-07-01
We present a path integral method to derive closed-form solutions for option prices in a stochastic volatility model. The method is explained in detail for the pricing of a plain vanilla option. The flexibility of our approach is demonstrated by extending the realm of closed-form option price formulas to the case where both the volatility and interest rates are stochastic. This flexibility is promising for the treatment of exotic options. Our analytical formulas are tested with numerical Monte Carlo simulations.
Experimental and Theoretical Basis for a Closed-Form Spectral BRDF Model
2015-09-17
SPECTRAL BRDF MODEL DISSERTATION Presented to the Faculty Graduate School of Engineering and Management Air Force Institute of Technology Air University Air...of Engineering and Management AFIT-ENP-DS-15-S-021 Abstract The microfacet class of BRDF models is frequently used to calculate optical scatter from...Lpath Path radiance xx Ls Scattered radiance ↔ M Mueller matrix P Pre-factor term Q Polarization factor Rd Relative difference S Scaling relationship
Closed-form estimates of the domain of attraction for nonlinear systems via fuzzy-polynomial models.
Pitarch, José Luis; Sala, Antonio; Ariño, Carlos Vicente
2014-04-01
In this paper, the domain of attraction of the origin of a nonlinear system is estimated in closed form via level sets with polynomial boundaries, iteratively computed. In particular, the domain of attraction is expanded from a previous estimate, such as a classical Lyapunov level set. With the use of fuzzy-polynomial models, the domain of attraction analysis can be carried out via sum of squares optimization and an iterative algorithm. The result is a function that bounds the domain of attraction, free from the usual restriction of being positive and decrescent in all the interior of its level sets.
NASA Astrophysics Data System (ADS)
Ahmadian, Mehdi; Blanchard, Emmanuel
2011-02-01
This article provides a non-dimensionalised closed-form analysis of semi-active vehicle suspensions, using a quarter-car model. The derivation of the closed-form solutions for three indices that can be used for ride comfort, vehicle handling, and stability are presented based on non-dimensionalised suspension parameters. The behaviour of semi-active vehicle suspensions is evaluated using skyhook, groundhook, and hybrid control policies, and compared with passive suspensions. The relationship between vibration isolation, suspension deflection, and road holding is studied, using three performance indices based on the mean square of the sprung mass acceleration, rattle space, and tyre deflection, respectively. The results of the study indicate that the hybrid control policy yields significantly better comfort than a passive suspension, without reducing the road-holding quality or increasing the suspension displacement for typical passenger cars. The results also indicate that for typical passenger cars, the hybrid control policy results in a better compromise between comfort, road holding and suspension travel requirements than both the skyhook and groundhook control methods.
Tang, Yongqiang
2017-02-22
We derive the closed-form restricted maximum likelihood estimator and Kenward-Roger's variance estimator for fixed effects in the mixed effects model for repeated measures (MMRM) when the missing data pattern is monotone. As an important application of the analytic result, we present the formula for calculating the power of treatment comparison using the Wald t-test with the Kenward-Roger adjusted variance estimate in MMRM. It allows adjustment for baseline covariates without the need to specify the covariate distribution in randomized trials. A simple two-step procedure is proposed to determine the sample size needed to achieve the targeted power. The proposed method performs well for both normal and moderately non-normal data even in small samples (n=20) in simulations. An antidepressant trial is analyzed for illustrative purposes. Copyright © 2017 John Wiley & Sons, Ltd.
NASA Astrophysics Data System (ADS)
Bhat, Chandra R.; Sener, Ipek N.
2009-09-01
This study focuses on accommodating spatial dependency in data indexed by geographic location. In particular, the emphasis is on accommodating spatial error correlation across observational units in binary discrete choice models. We propose a copula-based approach to spatial dependence modeling based on a spatial logit structure rather than a spatial probit structure. In this approach, the dependence between the logistic error terms of different observational units is directly accommodated using a multivariate logistic distribution based on the Farlie-Gumbel-Morgenstein (FGM) copula. The approach represents a simple and powerful technique that results in a closed-form analytic expression for the joint probability of choice across observational units, and is straightforward to apply using a standard and direct maximum likelihood inference procedure. There is no simulation machinery involved, leading to substantial computation gains relative to current methods to address spatial correlation. The approach is applied to teenagers’ physical activity participation levels, a subject of considerable interest in the public health, transportation, sociology, and adolescence development fields. The results indicate that failing to accommodate heteroscedasticity and spatial correlation can lead to inconsistent and inefficient parameter estimates, as well as incorrect conclusions regarding the elasticity effects of exogenous variables.
Leier, Andre; Barrio, Manuel; Marquez-Lago, Tatiana T
2014-06-06
In order to systematically understand the qualitative and quantitative behaviour of chemical reaction networks, scientists must derive and analyse associated mathematical models. However, biochemical systems are often very large, with reactions occurring at multiple time scales, as evidenced by signalling pathways and gene expression kinetics. Owing to the associated computational costs, it is then many times impractical, if not impossible, to solve or simulate these systems with an appropriate level of detail. By consequence, there is a growing interest in developing techniques for the simplification or reduction of complex biochemical systems. Here, we extend our recently presented methodology on exact reduction of linear chains of reactions with delay distributions in two ways. First, we report that it is now possible to deal with fully bi-directional monomolecular systems, including degradations, synthesis and generalized bypass reactions. Second, we provide all derivations of associated delays in analytical, closed form. Both advances have a major impact on further reducing computational costs, while still retaining full accuracy. Thus, we expect our new methodology to respond to current simulation needs in pharmaceutical, chemical and biological research.
NASA Technical Reports Server (NTRS)
Spuler, Linda M.; Ford, Patricia K.; Skeete, Darren C.; Hershman, Scot; Raviprakash, Pushpa; Arnold, John W.; Tran, Victor; Haenze, Mary Alice
2005-01-01
"Close Call Action Log Form" ("CCALF") is the name of both a computer program and a Web-based service provided by the program for creating an enhanced database of close calls (in the colloquial sense of mishaps that were avoided by small margins) assigned to the Center Operations Directorate (COD) at Johnson Space Center. CCALF provides a single facility for on-line collaborative review of close calls. Through CCALF, managers can delegate responses to employees. CCALF utilizes a pre-existing e-mail system to notify managers that there are close calls to review, but eliminates the need for the prior practices of passing multiple e-mail messages around the COD, then collecting and consolidating them into final responses: CCALF now collects comments from all responders for incorporation into reports that it generates. Also, whereas it was previously necessary to manually calculate metrics (e.g., numbers of maintenance-work orders necessitated by close calls) for inclusion in the reports, CCALF now computes the metrics, summarizes them, and displays them in graphical form. The reports and all pertinent information used to generate the reports are logged, tracked, and retained by CCALF for historical purposes.
NASA Astrophysics Data System (ADS)
Thoré, Philippe; Pastor, Franck; Pastor, Joseph; Kondo, Djimedo
2009-05-01
Though the solution to the limit analysis problem of the hollow sphere model—with a von Mises matrix and under spherical symmetry—is well known, it is not available, to our knowledge, for both isotropic loadings (tension and compression) in the case of a Coulomb matrix and partially for a Drucker-Prager matrix. In the present Note, we establish in a unified framework, for this class of materials, closed-form solutions for stress and strain fields in a hollow sphere under external isotropic tension and compression. These analytical results not only give useful reference solutions, but can also be considered as a part of a trial velocity field in the hollow sphere submitted to an arbitrary loading. Comparisons with 3D finite element-based limit analysis approaches and with recent results in the literature are provided. In addition to the established analytical results, we present a rigorous evaluation of a recent Gurson-type macroscopic criterion corresponding to the Drucker-Prager hollow sphere under an arbitrary loading, by means of the previous 3D limit analysis codes. To cite this article: Ph. Thoré et al., C. R. Mecanique 337 (2009).
Optimal Mortgage Refinancing: A Closed Form Solution
Agarwal, Sumit; Driscoll, John C.; Laibson, David I.
2013-01-01
We derive the first closed-form optimal refinancing rule: Refinance when the current mortgage interest rate falls below the original rate by at least 1ψ[ϕ+W(−exp(−ϕ))]. In this formula W(.) is the Lambert W-function, ψ=2(ρ+λ)σ,ϕ=1+ψ(ρ+λ)κ∕M(1−τ), ρ is the real discount rate, λ is the expected real rate of exogenous mortgage repayment, σ is the standard deviation of the mortgage rate, κ/M is the ratio of the tax-adjusted refinancing cost and the remaining mortgage value, and τ is the marginal tax rate. This expression is derived by solving a tractable class of refinancing problems. Our quantitative results closely match those reported by researchers using numerical methods. PMID:25843977
Optimal Mortgage Refinancing: A Closed Form Solution.
Agarwal, Sumit; Driscoll, John C; Laibson, David I
2013-06-01
We derive the first closed-form optimal refinancing rule: Refinance when the current mortgage interest rate falls below the original rate by at least [Formula: see text] In this formula W(.) is the Lambert W-function, [Formula: see text]ρ is the real discount rate, λ is the expected real rate of exogenous mortgage repayment, σ is the standard deviation of the mortgage rate, κ/M is the ratio of the tax-adjusted refinancing cost and the remaining mortgage value, and τ is the marginal tax rate. This expression is derived by solving a tractable class of refinancing problems. Our quantitative results closely match those reported by researchers using numerical methods.
NASA Astrophysics Data System (ADS)
Hoffman, R. L.
2005-04-01
A model is derived for the drain current (under DC steady-state operating conditions) of a long-channel thin-film transistor (TFT) with gate voltage-dependent channel mobility. A closed-form expression is obtained for cases in which the average mobility ( μavg) can be reasonably approximated by an nth-order polynomial curve fit; a more generalized expression allows the substitution of an arbitrary parameterized equation for μavg, yielding a closed-form expression in cases where the form of the selected mobility expression is such that the requisite integration can be carried out analytically. The model is employed to replicate measured drain current versus drain voltage ( ID- VDS) curves for exemplary zinc oxide and zinc tin oxide channel TFTs with highly non-ideal (i.e., gate voltage-dependent) mobility characteristics; in each case, excellent correlation to measured ID- VDS data is obtained, thus validating the proposed model. This model comprises a valuable tool in the preliminary development of novel TFTs for which standard device models are not, in general, appropriate.
NASA Astrophysics Data System (ADS)
Nazarenko, Lidiia; Bargmann, Swantje; Stolarski, Henryk
2017-01-01
The objective of this work is to present an approach allowing for inclusion of the complete Gurtin-Murdoch material surface equations in methods leading to closed-form formulas defining effective properties of particle-reinforced nanocomposites. Considering that all previous developments of the closed-form formulas for effective properties employ only some parts of the Gurtin-Murdoch model, its complete inclusion constitutes the main focus of this work. To this end, the recently introduced new notion of the energy-equivalent inhomogeneity is generalized to precisely include all terms of the model. The crucial aspect of that generalization is the identification of the energy associated with the last term of the Gurtin-Murdoch equation, i.e., with the surface gradient of displacements. With the help of that definition, the real nanoparticle and its surface possessing its own distinct elastic properties and residual stresses are replaced by an energy-equivalent inhomogeneity with properties incorporating all surface effects. Such equivalent inhomogeneity can then be used in combination with any existing homogenization method. In this work, the method of conditional moments is used to analyze composites with randomly dispersed spherical nanoparticles. Closed-form expressions for effective moduli are derived for both bulk and shear moduli. As numerical examples, nanoporous aluminum is investigated. The normalized bulk and shear moduli of nanoporous aluminum as a function of residual stresses are analyzed and evaluated in the context of other theoretical predictions.
Wang, Lejing; Fallavollita, Pascal; Zou, Rui; Chen, Xin; Weidert, Simon; Navab, Nassir
2012-05-01
For trauma and orthopedic surgery, maneuvering a mobile C-arm fluoroscope into a desired position to acquire an X-ray is a routine surgical task. The precision and ease of use of the C-arm becomes even more important for advanced interventional imaging techniques such as parallax-free X-ray image stitching. Today's standard mobile C-arms have been modeled with only five degrees of freedom (DOF), which definitely restricts their motions in 3-D Cartesian space. In this paper, we present a method to model both the mobile C-arm and patient's table as an integrated kinematic chain having six DOF without constraining table position. The closed-form solutions for the inverse kinematics problem are derived in order to obtain the required values for all C-arm joint and table movements to position the fluoroscope at a desired pose. The modeling method and the closed-form solutions can be applied to general isocentric or nonisocentric mobile C-arms. By achieving this we develop an efficient and intuitive inverse kinematics-based method for parallax-free panoramic X-ray imaging. In addition, we implement a 6-DOF C-arm system from a low-cost mobile fluoroscope to optimally acquire X-ray images based solely on the computation of the required movement for each joint by solving the inverse kinematics on a continuous basis. Through simulation experimentation, we demonstrate that the 6-DOF C-arm model has a larger working space than the 5-DOF model. C-arm repositioning experiments show the practicality and accuracy of our 6-DOF C-arm system. We also evaluate the novel parallax-free X-ray stitching method on phantom and dry bones. Using five trials, results show that parallax-free panoramas generated by our method are of high visual quality and within clinical tolerances for accurate evaluation of long bone geometry (i.e., image and metric measurement errors are less than 1% compared to ground-truth).
Closed-form solutions to surface Green`s functions
Umerski, A.
1997-02-01
We obtain closed-form analytic solutions for surface Green`s functions within arbitrary multiorbital models. The formulation is completely general, and is equally valid for empirical tight binding, linear-muffin-tin-orbital tight binding, screened Korringa-Kohn-Rostoker and other Green`s-function equivalent formalisms, where the Hamiltonian can be put into a localized (i.e., block-band) form. The solutions are applicable to finite or semi-infinite surface systems, with quite general substrate and overlayers, or even to superlattices. This is achieved by solving Dyson`s equations by means of a matrix-valued extension of the Moebius transformation. The analytical properties of the solutions are discussed, and by considering their asymptotic limit, a simple closed form for the exact (semi-infinite) surface Green`s function is obtained. The numerical calculation of the surface Green`s function (or of observable quantities such as the density of states) using this closed form is compared with previously known iterative procedures. We find that it is far faster, far more stable, and more accurate than the best iterative method. {copyright} {ital 1997} {ital The American Physical Society}
González-Navarro, H; Bañó, M C; Abad, C
2001-03-13
The behavior of prototypic fungal lipases in a water-restricted environment has been investigated by exploiting the reported experimental strategy that allows the trapping (freeze-drying) of the enzyme in the conformation present in aqueous solution and to subsequently assay it in nonaqueous media [Mingarro, I., Abad, C., and Braco, L. (1995) Proc. Natl. Acad. Sci. U.S.A. 92, 3308-3312]. We now report, using simple esterification as well as acidolysis (triglycerides as substrates) as nonaqueous model reactions, that the presence of a detergent (n-octyl-beta-glucopyranoside) in the freeze-drying buffer, at concentrations below the critical micellar concentration, generates different catalytically active (kinetically trapped) conformational states of the enzyme. These activated forms exquisitely discriminate between short- and long-chain fatty acids, suggesting that they can be correlated with intermediate conformations of the protein sufficiently open to permit the access of relatively small but not large substrates. Additional data obtained from aqueous solution activity measurements in the presence of detergent revealed that the fungal lipase retains an active conformation induced by high detergent concentration (30 mM) for a long period of time, a 'memory effect', which is stabilized in the absence of a well-defined interface by few detergent molecules. Together these results provide support to a model of lipase action involving several equilibrium states (closed, intermediate, and open), which can be modulated by the composition of the microenvironment, i.e., by the detergent concentration.
46 CFR 308.533 - Closing report, Form MA-313.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 46 Shipping 8 2014-10-01 2014-10-01 false Closing report, Form MA-313. 308.533 Section 308.533 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance Open Policy War Risk Cargo Insurance § 308.533 Closing report, Form MA-313....
Closed Forms for 4-Parameter Families of Integrals
ERIC Educational Resources Information Center
Dana-Picard, Thierry; Zeitoun, David G.
2009-01-01
We compute closed forms for two multiparameter families of definite integrals, thus obtaining combinatorial formulas. As a consequence, a surprising formula is derived between a definite integral and an improper integral for the same parametric function.
Bennett, Herbert S.; Filliben, James J.
2002-01-01
A critical issue identified in both the technology roadmap from the Optoelectronics Industry Development Association and the roadmaps from the National Electronics Manufacturing Initiative, Inc. is the need for predictive computer simulations of processes, devices, and circuits. The goal of this paper is to respond to this need by representing the extensive amounts of theoretical data for transport properties in the multi-dimensional space of mole fractions of AlAs in Ga1−xAlxAs, dopant densities, and carrier densities in terms of closed form analytic expressions. Representing such data in terms of closed-form analytic expressions is a significant challenge that arises in developing computationally efficient simulations of microelectronic and optoelectronic devices. In this paper, we present a methodology to achieve the above goal for a class of numerical data in the bounded two-dimensional space of mole fraction of AlAs and dopant density. We then apply this methodology to obtain closed-form analytic expressions for the effective intrinsic carrier concentrations at 300 K in n-type and p-type Ga1−xAlxAs as functions of the mole fraction x of AlAs between 0.0 and 0.3. In these calculations, the donor density ND for n-type material varies between 1016 cm−3 and 1019 cm−3 and the acceptor density NA for p-type materials varies between 1016 cm−3 and 1020 cm−3. We find that p-type Ga1−xAlxAs presents much greater challenges for obtaining acceptable analytic fits whenever acceptor densities are sufficiently near the Mott transition because of increased scatter in the numerical computer results for solutions to the theoretical equations. The Mott transition region in p-type Ga1−xAlxAs is of technological significance for mobile wireless communications systems. This methodology and its associated principles, strategies, regression analyses, and graphics are expected to be applicable to other problems beyond the specific case of effective intrinsic carrier
Regge calculus models of closed lattice universes
NASA Astrophysics Data System (ADS)
Liu, Rex G.; Williams, Ruth M.
2016-01-01
This paper examines the behavior of closed "lattice universes" wherein masses are distributed in a regular lattice on the Cauchy surfaces of closed vacuum universes. Such universes are approximated using a form of Regge calculus originally developed by Collins and Williams to model closed Friedmann-Lemaître-Robertson-Walker universes. We consider two types of lattice universes, one where all masses are identical to each other and another where one mass gets perturbed in magnitude. In the unperturbed universe, we consider the possible arrangements of the masses in the Regge Cauchy surfaces and demonstrate that the model will only be stable if each mass lies within some spherical region of convergence. We also briefly discuss the existence of Regge models that are dual to the ones we have considered. We then model a perturbed lattice universe and demonstrate that the model's evolution is well behaved, with the expansion increasing in magnitude as the perturbation is increased.
46 CFR 308.533 - Closing report, Form MA-313.
Code of Federal Regulations, 2010 CFR
2010-10-01
... Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance Ii-Open Policy War Risk Cargo Insurance § 308.533 Closing report, Form MA-313. This form, which may be obtained from the American War Risk Agency or MARAD, shall be filed...
46 CFR 308.533 - Closing report, Form MA-313.
Code of Federal Regulations, 2011 CFR
2011-10-01
... Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance Ii-Open Policy War Risk Cargo Insurance § 308.533 Closing report, Form MA-313. This form, which may be obtained from the American War Risk Agency or MARAD, shall be filed...
46 CFR 308.533 - Closing report, Form MA-313.
Code of Federal Regulations, 2013 CFR
2013-10-01
... Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance Ii-Open Policy War Risk Cargo Insurance § 308.533 Closing report, Form MA-313. This form, which may be obtained from the American War Risk Agency or MARAD, shall be filed...
Stars Form Surprisingly Close to Milky Way's Black Hole
NASA Astrophysics Data System (ADS)
2005-10-01
The supermassive black hole at the center of the Milky Way has surprisingly helped spawn a new generation of stars, according to observations from NASA's Chandra X-ray Observatory. This novel mode of star formation may solve several mysteries about the supermassive black holes that reside at the centers of nearly all galaxies. "Massive black holes are usually known for violence and destruction," said Sergei Nayakshin of the University of Leicester, United Kingdom, and coauthor of a paper on this research in an upcoming issue of the Monthly Notices of the Royal Astronomical Society. "So it's remarkable that this black hole helped create new stars, not just destroy them." Black holes have earned their fearsome reputation because any material -- including stars -- that falls within the so-called event horizon is never seen again. However, these new results indicate that the immense disks of gas known to orbit many black holes at a "safe" distance from the event horizon can help nurture the formation of new stars. Animation of Stars Forming Around Black Hole Animation of Stars Forming Around Black Hole This conclusion came from new clues that could only be revealed in X-rays. Until the latest Chandra results, astronomers have disagreed about the origin of a mysterious group of massive stars discovered by infrared astronomers to be orbiting less than a light year from the Milky Way's central black hole, a.k.a. Sagittarius A*, or Sgr A*. At such close distances to Sgr A*, the standard model for star formation predicts that gas clouds from which stars form should have been ripped apart by tidal forces from the black hole. Two models to explain this puzzle have been proposed. In the disk model, the gravity of a dense disk of gas around Sgr A* offsets the tidal forces and allows stars to form; in the migration model, the stars formed in a star cluster far away from the black hole and migrated in to form the ring of massive stars. The migration scenario predicts about a
A Closed Form Solution for an Unorthodox Trigonometric Integral
ERIC Educational Resources Information Center
Wu, Yan
2009-01-01
A closed form solution for the trigonometric integral [integral]sec[superscript 2k+1]xdx, k=0,1,2,..., is presented in this article. The result will fill the gap in another trigonometric integral [integral]sec[superscript 2m+1] x tan[superscript 2n]xdx, which is neglected by most of the calculus textbooks due to its foreseeable unorthodox solution…
NASA Technical Reports Server (NTRS)
Sivells, James C; Deters, Owen J
1946-01-01
A method is presented for determining the jet-boundary and plan-form corrections necessary for application to test data for a partial-span model with a reflection plane, an end plate, or no end plate in a closed circular wind tunnel. Examples are worked out for a partial-span model with each of the three end conditions in the Langley 19-foot pressure tunnel and the corrections are applied to measured values of lift, drag, pitching-moment, rolling-moment, and yawing-moment coefficients.
Generalizing Merton's approach of pricing risky debt: some closed-form results
NASA Astrophysics Data System (ADS)
Wang, D. F.
In this work, I generalize Merton's approach of pricing risky debt to the case where the interest rate risk is modeled by the CIR term structure. Closed-form result for pricing the debt is given for the case where the firm value has non-zero correlation with the interest rate. This extends previous closed-form pricing formular of zero-correlation case to the generic one of non-zero correlation between the firm value and the interest rate.
A simple closed-form solution for assessing concentration uncertainty
NASA Astrophysics Data System (ADS)
de Barros, F. P. J.; Fiori, Aldo; Bellin, Alberto
2011-12-01
We propose closed-form approximate solutions for the moments of a nonreactive tracer that can be used in applications, such as risk analysis. This is in line with the tenet that analytical solutions provide useful information, with minimum cost, during initial site characterization efforts and can serve as a preliminary screening tool when used with prior knowledge. We show that with the help of a few assumptions, the first-order solutions of the concentration moments proposed by Fiori and Dagan (2000) can be further simplified to assume a form similar to well-known deterministic solutions, therefore facilitating their use in applications. A highly anisotropic formation is assumed, and we neglect the transverse components of the two-particle correlation trajectory. The proposed solution compares well with the work of Fiori and Dagan while presenting the same simplicity of use of existing solutions for homogeneous porous media.
Form 5-Mining venture agreement model form
Not Available
1984-01-01
This text acts as a reference of the basic terms and conditions for a negotiated mining venture agreement. Alternative clauses and provisions, along with extensive commentary, are supplied. The model form contains many articles which define and detail the process.
Delay chemical master equation: direct and closed-form solutions.
Leier, Andre; Marquez-Lago, Tatiana T
2015-07-08
The stochastic simulation algorithm (SSA) describes the time evolution of a discrete nonlinear Markov process. This stochastic process has a probability density function that is the solution of a differential equation, commonly known as the chemical master equation (CME) or forward-Kolmogorov equation. In the same way that the CME gives rise to the SSA, and trajectories of the latter are exact with respect to the former, trajectories obtained from a delay SSA are exact representations of the underlying delay CME (DCME). However, in contrast to the CME, no closed-form solutions have so far been derived for any kind of DCME. In this paper, we describe for the first time direct and closed solutions of the DCME for simple reaction schemes, such as a single-delayed unimolecular reaction as well as chemical reactions for transcription and translation with delayed mRNA maturation. We also discuss the conditions that have to be met such that such solutions can be derived.
A subsequent closed-form description of propagated signaling phenomena in the membrane of an axon
NASA Astrophysics Data System (ADS)
Melendy, Robert. F.
2016-05-01
I recently introduced a closed-form description of propagated signaling phenomena in the membrane of an axon [R.F. Melendy, Journal of Applied Physics 118, 244701 (2015)]. Those results demonstrate how intracellular conductance, the thermodynamics of magnetization, and current modulation, function together in generating an action potential in a unified, closed-form description. At present, I report on a subsequent closed-form model that unifies intracellular conductance and the thermodynamics of magnetization, with the membrane electric field, Em. It's anticipated this work will compel researchers in biophysics, physical biology, and the computational neurosciences, to probe deeper into the classical and quantum features of membrane magnetization and signaling, informed by the computational features of this subsequent model.
17 CFR 239.14 - Form N-2 for closed end management investment companies registered on Form N-8A.
Code of Federal Regulations, 2011 CFR
2011-04-01
... management investment companies registered on Form N-8A. 239.14 Section 239.14 Commodity and Securities... Registration Statements § 239.14 Form N-2 for closed end management investment companies registered on Form N... closed end management investment companies registered under the Investment Company Act of 1940 on form...
17 CFR 239.14 - Form N-2 for closed end management investment companies registered on Form N-8A.
Code of Federal Regulations, 2010 CFR
2010-04-01
... management investment companies registered on Form N-8A. 239.14 Section 239.14 Commodity and Securities... Registration Statements § 239.14 Form N-2 for closed end management investment companies registered on Form N... closed end management investment companies registered under the Investment Company Act of 1940 on form...
Looking Closely at "Medusa": Star Forming Regions in NGC 4194
NASA Technical Reports Server (NTRS)
Weistrop, D.; Eggers, D.; Nelson, C. H.; Kaiser, M. E.
2004-01-01
The "Medusa" (NGC 4194, Mrk 201) is a blue compact galaxy, with strong far infrared and radio emission. Ground-based observations exhibit a distorted image with a tidal tail and regions of strong star formation. A population of massive O and early B stars is evident from the IUE spectra HST survey of Seyfert and starburst galaxies notes NCG 4194 is an HII galaxy with lumpy HII regions and knots. The central starburst is apparently produced by a galaxy merger. As part of an investigation of star formation in interacting galaxies, we have obtained ultraviolet and visible images of the central regions of NGC 4194 with the Space Telescope Imaging Spectrograph on HST. Imaging was obtained in two ultraviolet (FUV-MAMA+F25QTZ, NUV-MAMA+F25CN182) and one visible (CCD+F28X50LP) band. Individual star forming knots (at HST resolution) have been identified. We present sized and luminosities for the individual knots, and the knot luminosity function. We compare our data to current starburst models to constrain stellar ages and populations. Knot characteristics as a function of location in the galaxy will also be discussed.
Closed form expressions for a consistent stress material nonlinear finite element
NASA Astrophysics Data System (ADS)
Knipe, Richard Lee
Finite element expressions for two dimensional elasto-plasticity problems were implemented in closed form. These closed form expressions are based upon a distribution of the elasto-plastic constitutive relationship that is consistent with the interpolating functions used for the displacement. Closed form expressions for the element tangent stiffness matrix and initial stress nodal load vector were developed for the non hierarchic constant, linear, and quadratic strain triangle. Decreased solution times were obtained when using the closed form expressions instead of expressions based on numerical integration. The quality of the solutions obtained from the closed form expressions was measured against published solutions for two dimensional elasto-plasticity problems.
Mathematical modeling relevant to closed artificial ecosystems
DeAngelis, D.L.
2003-01-01
The mathematical modeling of ecosystems has contributed much to the understanding of the dynamics of such systems. Ecosystems can include not only the natural variety, but also artificial systems designed and controlled by humans. These can range from agricultural systems and activated sludge plants, down to mesocosms, microcosms, and aquaria, which may have practical or research applications. Some purposes may require the design of systems that are completely closed, as far as material cycling is concerned. In all cases, mathematical modeling can help not only to understand the dynamics of the system, but also to design methods of control to keep the system operating in desired ranges. This paper reviews mathematical modeling relevant to the simulation and control of closed or semi-closed artificial ecosystems designed for biological production and recycling in applications in space. Published by Elsevier Science Ltd on behalf of COSPAR.
Mathematical modeling relevant to closed artificial ecosystems.
DeAngelis, Donald L
2003-01-01
The mathematical modeling of ecosystems has contributed much to the understanding of the dynamics of such systems. Ecosystems can include not only the natural variety, but also artificial systems designed and controlled by humans. These can range from agricultural systems and activated sludge plants, down to mesocosms, microcosms, and aquaria, which may have practical or research applications. Some purposes may require the design of systems that are completely closed, as far as material cycling is concerned. In all cases, mathematical modeling can help not only to understand the dynamics of the system, but also to design methods of control to keep the system operating in desired ranges. This paper reviews mathematical modeling relevant to the simulation and control of closed or semi-closed artificial ecosystems designed for biological production and recycling in applications in space.
Reverse engineering of free-form surface based on the closed-loop theory.
He, Xue Ming; He, Jun Fei; Wu, Mei Ping; Zhang, Rong; Ji, Xiao Gang
2015-01-01
To seek better methods of measurement and more accurate model of reconstruction in the field of reverse engineering has been the focus of researchers. Based on this, a new method of adaptive measurement, real-time reconstruction, and online evaluation of free-form surface was presented in this paper. The coordinates and vectors of the prediction points are calculated according to a Bézier curve which is fitted by measured points. Final measured point cloud distribution is in agreement with the geometric characteristics of the free-form surfaces. Fitting the point cloud to a surface model by the nonuniform B-spline method, extracting some check points from the surface models based on grids and a feature on the surface, review the location of these check points on the surface with CMM and evaluate the model, and then update the surface model to meet the accuracy. Integrated measurement, reconstruction, and evaluation, with the closed-loop reverse process, established an accurate model. The results of example show that the measuring points are distributed over the surface according to curvature, and the reconstruction model can be completely expressed with micron level. Meanwhile, measurement, reconstruction and evaluation are integrated in forms of closed-loop reverse system.
Low-Frequency Closed-Form Expressions for Crosstalk Between Twisted Wire Pirs
NASA Astrophysics Data System (ADS)
Lansink Rotgerink, J. H. G. J.; Verpoorte, J.
2016-05-01
Crosstalk between two twisted wire pairs of equal and unequal twist rate is analysed and compared. Low-frequency approximations to the Multi- conductor Transmission Line equations are used to derive closed-form expressions for near-end crosstalk. Such analysis on cable configurations with different twist scenarios gives insight into sensitivity on relevant twist parameters as well as dependencies of crosstalk on all other model parameters. Results show that crosstalk between twisted pairs of equal twist rate behaves similar to that between untwisted wire pairs. On the contrary, an ideal combination of twisted pairs, by for instance doubling the twist rate in one of the pairs, causes crosstalk to vanish up to linear order. The performed analysis and derived closed-form expressions agree to measured crosstalk results and can lead to good understanding of upper and lower boundaries for crosstalk in different cable configurations.
Closed-Form Solutions for Free Vibration Frequencies of Functionally Graded Euler-Bernoulli Beams
NASA Astrophysics Data System (ADS)
Chen, W. R.; Chang, H.
2017-03-01
The bending vibration of a functionally graded Euler-Bernoulli beam is investigated by the transformed-section method. The material properties of the functionally graded beam (FGB) are assumed to vary across its thickness according to a simple power law. Closed-form solutions for free vibration frequencies of FGBs with classical boundary conditions are derived. Some analytical results are compared with numerical results found in the published literature to verify the accuracy of the model presented, and a good agreement between them is observed.
A Simplified, Closed-Form Method for Screening Spacecraft Orbital Heating Variations
NASA Technical Reports Server (NTRS)
Rickman, S. L.
2002-01-01
A closed-form analytical technique has been developed to screen orbital average heating variations as a function of beta angle, altitude, surface area, and surface optical properties. Using planetary view factor equations for surfaces parallel-to and normal-to the local vertical, a cylindrical umbral shadow approximation, and a simplified albedo flux model, heating rate equations are formulated and then integrated to obtain orbital average heating. The results are compared to detailed analytical predictions using Monte Carlo integration and an assessment of error is presented.
NASA Astrophysics Data System (ADS)
Myers, Philip C.
2017-03-01
New models of star-forming filamentary clouds are presented in order to quantify their properties and to predict their evolution. These 2D axisymmetric models describe filaments that have no core, one low-mass core, and one cluster-forming core. They are based on Plummer-like cylinders and spheroids that are bounded by a constant-density surface of finite extent. In contrast to 1D Plummer-like models, they have specific values of length and mass, they approximate observed column density maps, and their distributions of column density (N-pdfs) are pole-free. Each model can estimate the star-forming potential of a core-filament system by identifying the zone of gas dense enough to form low-mass stars and by counting the number of enclosed thermal Jeans masses. This analysis suggests that the Musca central filament may be near the start of its star-forming life, with enough dense gas to make its first ∼3 protostars, while the Coronet filament is near the midpoint of its star formation, with enough dense gas to add ∼8 protostars to its ∼20 known stars. In contrast, L43 appears to be near the end of its star-forming life, since it lacks enough dense gas to add any new protostars to the two young stellar objectsalready known.
Closed-form solutions for atomspheric flight with applications to shuttle guidance
NASA Technical Reports Server (NTRS)
Ingram, H. L.
1972-01-01
Closed-form solutions for the motion of a rocket-powered vehicle during atmospheric ascent and closed-form solutions for unpowered atmospheric reentry are developed. These closed-form solutions are then used to develop a simplified guidance scheme and to develop a variation-of-parameters integration of more accurate equations of motion with the closed-form solutions as base solutions. The variation-of-parameters integration of the more accurate equations of motion also allows the transition partial derivative matrices associated with these equations to be easily developed. Then the partial derivative transition matrices are used to develop a guidance scheme based on the more accurate equations of motion instead of the less accurate closed-form solutions.
NASA Astrophysics Data System (ADS)
Li, Dunling; Loew, Murray H.
2004-05-01
This paper provides a theoretical foundation for the closed-form expression of model observers on compressed images. In medical applications, model observers, especially the channelized Hotelling observer, have been successfully used to predict human observer performance and to evaluate image quality for detection tasks in various backgrounds. To use model observers, however, requires knowledge of noise statistics. This paper first identifies quantization noise as the sole distortion source in transform coding, one of the most commonly used methods for image compression. Then, it represents transform coding as a 1-D block-based matrix expression, it further derives first and second moments, and the probability density function (pdf) of the compression noise at pixel, block and image levels. The compression noise statistics depend on the transform matrix and the quantization matrix in the transform coding algorithm. Compression noise is jointly normally distributed when the dimension of the transform (the block size) is typical and the contents of image sets vary randomly. Moreover, this paper uses JPEG as a test example to verify the derived statistics. The test simulation results show that the closed-form expression of JPEG quantization and compression noise statistics correctly predicts the estimated ones from actual images.
Resolving the biophysics of axon transmembrane polarization in a single closed-form description
NASA Astrophysics Data System (ADS)
Melendy, Robert F.
2015-12-01
When a depolarizing event occurs across a cell membrane there is a remarkable change in its electrical properties. A complete depolarization event produces a considerably rapid increase in voltage that propagates longitudinally along the axon and is accompanied by changes in axial conductance. A dynamically changing magnetic field is associated with the passage of the action potential down the axon. Over 75 years of research has gone into the quantification of this phenomenon. To date, no unified model exist that resolves transmembrane polarization in a closed-form description. Here, a simple but formative description of propagated signaling phenomena in the membrane of an axon is presented in closed-form. The focus is on using both biophysics and mathematical methods for elucidating the fundamental mechanisms governing transmembrane polarization. The results presented demonstrate how to resolve electromagnetic and thermodynamic factors that govern transmembrane potential. Computational results are supported by well-established quantitative descriptions of propagated signaling phenomena in the membrane of an axon. The findings demonstrate how intracellular conductance, the thermodynamics of magnetization, and current modulation function together in generating an action potential in a unified closed-form description. The work presented in this paper provides compelling evidence that three basic factors contribute to the propagated signaling in the membrane of an axon. It is anticipated this work will compel those in biophysics, physical biology, and in the computational neurosciences to probe deeper into the classical and quantum features of membrane magnetization and signaling. It is hoped that subsequent investigations of this sort will be advanced by the computational features of this model without having to resort to numerical methods of analysis.
Resolving the biophysics of axon transmembrane polarization in a single closed-form description
Melendy, Robert F.
2015-12-28
When a depolarizing event occurs across a cell membrane there is a remarkable change in its electrical properties. A complete depolarization event produces a considerably rapid increase in voltage that propagates longitudinally along the axon and is accompanied by changes in axial conductance. A dynamically changing magnetic field is associated with the passage of the action potential down the axon. Over 75 years of research has gone into the quantification of this phenomenon. To date, no unified model exist that resolves transmembrane polarization in a closed-form description. Here, a simple but formative description of propagated signaling phenomena in the membrane of an axon is presented in closed-form. The focus is on using both biophysics and mathematical methods for elucidating the fundamental mechanisms governing transmembrane polarization. The results presented demonstrate how to resolve electromagnetic and thermodynamic factors that govern transmembrane potential. Computational results are supported by well-established quantitative descriptions of propagated signaling phenomena in the membrane of an axon. The findings demonstrate how intracellular conductance, the thermodynamics of magnetization, and current modulation function together in generating an action potential in a unified closed-form description. The work presented in this paper provides compelling evidence that three basic factors contribute to the propagated signaling in the membrane of an axon. It is anticipated this work will compel those in biophysics, physical biology, and in the computational neurosciences to probe deeper into the classical and quantum features of membrane magnetization and signaling. It is hoped that subsequent investigations of this sort will be advanced by the computational features of this model without having to resort to numerical methods of analysis.
NASA Astrophysics Data System (ADS)
Hariharan, Venkatnarayan; Vasi, Juzer; Ramgopal Rao, V.
2009-02-01
In developing the drain current model of a symmetrically driven, undoped (or lightly doped) symmetric double-gate MOSFET (SDGFET), one encounters a transcendental equation relating the value of an intermediate variable β (which is related to the inversion charge areal density and also surface-potential) to the gate and drain voltages; as a result, it doesn't have a closed form solution. From a compact modeling perspective, it is desirable to have closed form expressions in order to implement them in a circuit simulator. In this paper, we present an accurate closed form approximation for the inversion charge areal density, based on the Lambert-W function. We benchmark our approximation against other existing approximations and show that our approximation is computationally the most efficient and numerically the most robust, at a reduced but acceptable accuracy. Hence, it is suitable for use in implementing inversion charge based compact models.
46 CFR 308.534 - Certificate to be attached to closing report, Form MA-313-A.
Code of Federal Regulations, 2010 CFR
2010-10-01
... EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance Ii-Open Policy War Risk Cargo Insurance... to be attached to the closing report, Form MA-313-A, may be obtained from the American War...
46 CFR 308.534 - Certificate to be attached to closing report, Form MA-313-A.
Code of Federal Regulations, 2013 CFR
2013-10-01
... EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance Ii-Open Policy War Risk Cargo Insurance... to be attached to the closing report, Form MA-313-A, may be obtained from the American War...
46 CFR 308.534 - Certificate to be attached to closing report, Form MA-313-A.
Code of Federal Regulations, 2011 CFR
2011-10-01
... EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance Ii-Open Policy War Risk Cargo Insurance... to be attached to the closing report, Form MA-313-A, may be obtained from the American War...
The spaces of non-contractible closed curves in compact space forms
NASA Astrophysics Data System (ADS)
Taimanov, I. A.
2016-10-01
The rational equivariant cohomology of noncontractible loop spaces is calculated for compact space forms. It is also shown how to use these calculations to establish the existence of closed geodesics. Bibliography: 18 titles.
Closed-Form Evaluation of Mutual Coupling in a Planar Array of Circular Apertures
NASA Technical Reports Server (NTRS)
Bailey, M. C.
1996-01-01
The integral expression for the mutual admittance between circular apertures in a planar array is evaluated in closed form. Very good accuracy is realized when compared with values that were obtained by numerical integration. Utilization of this closed-form expression, for all element pairs that are separated by more than one element spacing, yields extremely accurate results and significantly reduces the computation time that is required to analyze the performance of a large electronically scanning antenna array.
Bayesian Multiscale Modeling of Closed Curves in Point Clouds.
Gu, Kelvin; Pati, Debdeep; Dunson, David B
2014-10-01
Modeling object boundaries based on image or point cloud data is frequently necessary in medical and scientific applications ranging from detecting tumor contours for targeted radiation therapy, to the classification of organisms based on their structural information. In low-contrast images or sparse and noisy point clouds, there is often insufficient data to recover local segments of the boundary in isolation. Thus, it becomes critical to model the entire boundary in the form of a closed curve. To achieve this, we develop a Bayesian hierarchical model that expresses highly diverse 2D objects in the form of closed curves. The model is based on a novel multiscale deformation process. By relating multiple objects through a hierarchical formulation, we can successfully recover missing boundaries by borrowing structural information from similar objects at the appropriate scale. Furthermore, the model's latent parameters help interpret the population, indicating dimensions of significant structural variability and also specifying a 'central curve' that summarizes the collection. Theoretical properties of our prior are studied in specific cases and efficient Markov chain Monte Carlo methods are developed, evaluated through simulation examples and applied to panorex teeth images for modeling teeth contours and also to a brain tumor contour detection problem.
Physically based closed-form expression for the bimodal unsaturated hydraulic conductivity function.
Liu, Shiyu; Yasufuku, Noriyuki; Liu, Qiang; Hemanta, Hazarika
2013-01-01
Simulation of flow and contaminant transport through the vadose zone requires accurate parameterization of the soil hydraulic properties. This requirement is particularly important for soils with a complex structure. In the present study, a physically based closed-form expression for the bimodal unsaturated hydraulic conductivity function is proposed for soils with bimodal pore-size distribution. It combines the bimodal representation of the soil-water characteristic curve (SWCC) function of Liu with the conductivity representation model of Mualem. The proposed equations are defined by parameters that have physical significance, which can be related to the properties of the materials. Experimental data for the representation of bimodal SWCCs and corresponding hydraulic conductivity curves were used to demonstrate the applicability of the proposed functions. The proposed approaches resulted in good agreement with experimental data. These functions can potentially be used as an effective tool for identifying hydraulic porosities in mediums with a complex structure.
Closed form solution to the semi-infinite cylindrical shell problem.
NASA Technical Reports Server (NTRS)
Sanders, J. L., Jr.
1972-01-01
Reconsideration of the problem of a complete semiinfinite circular cylindrical shell with a square cage investigated earlier by Reissner and Simmonds (1966). It is shown that the solution can be found in closed form rather than in the form of Fourier series, provided that the boundary data on the end of the shell are 'slowly varying.'
Nagasawa, M.; Ida, S.
2011-12-01
We investigated the formation of close-in planets (hot Jupiters) by a combination of mutual scattering, Kozai effect, and tidal circularization, through N-body simulations of three gas giant planets, and compared the results with discovered close-in planets. We found that in about 350 cases out of 1200 runs ({approx}30%), the eccentricity of one of the planets is excited highly enough for tidal circularization by mutual close scatterings followed by secular effects due to outer planets, such as the Kozai mechanism, and the planet becomes a close-in planet through the damping of eccentricity and semimajor axis. The formation probability of close-in planets by such scattering is not affected significantly by the effect of the general relativity and inclusion of inertial modes in addition to fundamental modes in the tides. Detailed orbital distributions of the formed close-in planets and their counterpart distant planets in our simulations were compared with observational data. We focused on the possibility for close-in planets to retain non-negligible eccentricities ({approx}> 0.1) on timescales of {approx}10{sup 9} yr and have high inclinations, because close-in planets in eccentric or highly inclined orbits have recently been discovered. In our simulations we found that as many as 29% of the close-in planets have retrograde orbits, and the retrograde planets tend to have small eccentricities. On the other hand, eccentric close-in planets tend to have orbits of small inclinations.
Bayesian Multiscale Modeling of Closed Curves in Point Clouds
Gu, Kelvin; Pati, Debdeep; Dunson, David B.
2014-01-01
Modeling object boundaries based on image or point cloud data is frequently necessary in medical and scientific applications ranging from detecting tumor contours for targeted radiation therapy, to the classification of organisms based on their structural information. In low-contrast images or sparse and noisy point clouds, there is often insufficient data to recover local segments of the boundary in isolation. Thus, it becomes critical to model the entire boundary in the form of a closed curve. To achieve this, we develop a Bayesian hierarchical model that expresses highly diverse 2D objects in the form of closed curves. The model is based on a novel multiscale deformation process. By relating multiple objects through a hierarchical formulation, we can successfully recover missing boundaries by borrowing structural information from similar objects at the appropriate scale. Furthermore, the model’s latent parameters help interpret the population, indicating dimensions of significant structural variability and also specifying a ‘central curve’ that summarizes the collection. Theoretical properties of our prior are studied in specific cases and efficient Markov chain Monte Carlo methods are developed, evaluated through simulation examples and applied to panorex teeth images for modeling teeth contours and also to a brain tumor contour detection problem. PMID:25544786
A closed form for fluorescence correlation spectroscopy experiments in submicrometer structures.
Sanguigno, Luigi; De Santo, Ilaria; Causa, Filippo; Netti, Paolo
2010-12-01
Fluorescence correlation spectroscopy (FCS) is a powerful technique for measuring low concentrations of fluorescent molecules and their diffusion coefficients in an open detection volume. However, in several practical cases, when FCS measurements are carried out in small compartments like microchannels, neglecting boundary effects could lead to erroneous results. Here, a close form solution is proposed to explicitly account for the presence of walls located at a distance comparable with the characteristic detection volume lengths. We derive a one-dimensional diffusion constrained model and then generalize the solution to the two- and the three-dimensional constrained cases. We further indicate within which limits the standard autocorrelation function (ACF) model gives reliable results in microconfinement. Our model relies just on the assumption of elastic hits at the system walls and succeeds in describing the ACF of fluorescent probes confined along one direction. Through the analysis of FCS experimental data, we are able to predict the correct shape of the ACF in channels of micrometric and submicrometric width and measure the extent of lateral confinement. In addition, it permits the investigation of microstructured material features such as cages and cavities having dimensions on the micrometric range. On the basis of the proposed model, we also show in which conditions confinement could generate an apparent time dependent probe mobility, thus allowing a proper interpretation of the transport process taking place in submicrometric compartments.
Closed form Vaidya-Tikekar type charged fluid spheres with pressure
NASA Astrophysics Data System (ADS)
Bijalwan, Naveen; Gupta, Y. K.
2011-08-01
Recently, Bijalwan (Astrophys. Space Sci. doi:
12 CFR Appendix A to Part 213 - Model Forms
Code of Federal Regulations, 2011 CFR
2011-01-01
... (REGULATION M) Pt. 213, App. A Appendix A to Part 213—Model Forms A-1Model Open-End or Finance Vehicle Lease Disclosures A-2Model Closed-End or Net Vehicle Lease Disclosures A-3Model Furniture Lease Disclosures...
Wu, Xiaotian; Li, Jun; Nekka, Fahima
2015-04-01
The current study aims to provide the closed form solutions of one-compartment open models exhibiting simultaneous linear and nonlinear Michaelis-Menten elimination kinetics for single- and multiple-dose intravenous bolus administrations. It can be shown that the elimination half-time ([Formula: see text]) has a dose-dependent property and is upper-bounded by [Formula: see text] of the first-order elimination model. We further analytically distinguish the dominant role of different elimination pathways in terms of model parameters. Moreover, for the case of multiple-dose intravenous bolus administration, the existence and local stability of the periodic solution at steady state are established. The closed form solutions of the models are obtained through a newly introduced function motivated by the Lambert W function.
Katabatic Flow: A Closed-Form Solution with Spatially-Varying Eddy Diffusivities
NASA Astrophysics Data System (ADS)
Giometto, M. G.; Grandi, R.; Fang, J.; Monkewitz, P. A.; Parlange, M. B.
2017-02-01
The Nieuwstadt closed-form solution for the stationary Ekman layer is generalized for katabatic flows within the conceptual framework of the Prandtl model. The proposed solution is valid for spatially-varying eddy viscosity and diffusivity (O'Brien type) and constant Prandtl number ( Pr). Variations in the velocity and buoyancy profiles are discussed as a function of the dimensionless model parameters z_0 ≡ hat{z}_0 hat{N}^2 Pr sin {(α )} |hat{b}_s |^{-1} and λ ≡ hat{u}_{ref}hat{N} √{Pr} |hat{b}_s |^{-1}, where hat{z}_0 is the hydrodynamic roughness length, hat{N} is the Brunt-Väisälä frequency, α is the surface sloping angle, hat{b}_s is the imposed surface buoyancy, and hat{u}_{ref} is a reference velocity scale used to define eddy diffusivities. Velocity and buoyancy profiles show significant variations in both phase and amplitude of extrema with respect to the classic constant it{K} model and with respect to a recent approximate analytic solution based on the Wentzel-Kramers-Brillouin theory. Near-wall regions are characterized by relatively stronger surface momentum and buoyancy gradients, whose magnitude is proportional to z_0 and to λ . In addition, slope-parallel momentum and buoyancy fluxes are reduced, the low-level jet is further displaced toward the wall, and its peak velocity depends on both z_0 and λ.
Closed-form approximations for two-dimensional groundwater age patterns in a fresh water lens.
Greskowiak, Janek; Röper, Tania; Post, Vincent E A
2013-01-01
Simple closed-form approximations are presented for calculating the steady-state groundwater age distribution in two-dimensional vertical cross sections of idealized fresh water lenses overlying salt water, for aquifers that are vertically semi-infinite and of finite thickness. The approximations are developed on the basis of existing one-dimensional analytical solutions for travel-time calculation in fresh water lenses and approximate streamline formulations. The two-dimensional age distributions based on the closed-form solutions match convincingly with numerical simulations. As expected, notable deviations from the numerical solution are encountered at the groundwater flow divide and when submarine groundwater discharge occurs. Ratios of recharge over hydraulic conductivities are varied to explore how the magnitude of the deviations changes, and it is found that the approximate closed-form solutions perform well over a range of conditions found in natural systems.
Modeling of Closed-Die Forging for Estimating Forging Load
NASA Astrophysics Data System (ADS)
Sheth, Debashish; Das, Santanu; Chatterjee, Avik; Bhattacharya, Anirban
2017-02-01
Closed die forging is one common metal forming process used for making a range of products. Enough load is to exert on the billet for deforming the material. This forging load is dependent on work material property and frictional characteristics of the work material with the punch and die. Several researchers worked on estimation of forging load for specific products under different process variables. Experimental data on deformation resistance and friction were used to calculate the load. In this work, theoretical estimation of forging load is made to compare this value with that obtained through LS-DYNA model facilitating the finite element analysis. Theoretical work uses slab method to assess forging load for an axi-symmetric upsetting job made of lead. Theoretical forging load estimate shows slightly higher value than the experimental one; however, simulation shows quite close matching with experimental forging load, indicating possibility of wide use of this simulation software.
12 CFR Appendix A to Part 213 - Model Forms
Code of Federal Regulations, 2010 CFR
2010-01-01
... 12 Banks and Banking 2 2010-01-01 2010-01-01 false Model Forms A Appendix A to Part 213 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM CONSUMER LEASING (REGULATION M) Pt. 213, App. A Appendix A to Part 213—Model Forms A-1Model Open-End or Finance Vehicle Lease Disclosures A-2Model Closed-End or...
NASA Astrophysics Data System (ADS)
Khoshelham, Kourosh
2016-04-01
Registration is often a prerequisite step in processing point clouds. While planar surfaces are suitable features for registration, most of the existing plane-based registration methods rely on iterative solutions for the estimation of transformation parameters from plane correspondences. This paper presents a new closed-form solution for the estimation of a rigid motion from a set of point-plane correspondences. The role of normalization is investigated and its importance for accurate plane fitting and plane-based registration is shown. The paper also presents a thorough evaluation of the closed-form solutions and compares their performance with the iterative solution in terms of accuracy, robustness, stability and efficiency. The results suggest that the closed-form solution based on point-plane correspondences should be the method of choice in point cloud registration as it is significantly faster than the iterative solution, and performs as well as or better than the iterative solution in most situations. The normalization of the point coordinates is also recommended as an essential preprocessing step for point cloud registration. An implementation of the closed-form solutions in MATLAB is available at: http://people.eng.unimelb.edu.au/kkhoshelham/research.html#directmotion.
46 CFR 308.534 - Certificate to be attached to closing report, Form MA-313-A.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 46 Shipping 8 2014-10-01 2014-10-01 false Certificate to be attached to closing report, Form MA-313-A. 308.534 Section 308.534 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance Open Policy War Risk Cargo Insurance §...
An exact closed form solution for constant area compressible flow with friction and heat transfer
NASA Technical Reports Server (NTRS)
Sturas, J. I.
1971-01-01
The well-known differential equation for the one-dimensional flow of a compressible fluid with heat transfer and wall friction has no known solution in closed form for the general case. This report presents a closed form solution for the special case of constant heat flux per unit length and constant specific heat. The solution was obtained by choosing the square of a dimensionless flow parameter as one of the independent variables to describe the flow. From this exact solution, an approximate simplified form is derived that is applicable for predicting subsonic flow performance characteristics for many types of constant area passages in internal flow. The data included in this report are considered sufficiently accurate for use as a guide in analyzing and designing internal gas flow systems.
The Weyl group and asymptotics: All supergravity billiards have a closed form general integral
NASA Astrophysics Data System (ADS)
Fré, Pietro; Sorin, Alexander S.
2009-07-01
In this paper we show that all supergravity billiards corresponding to σ-models on any U/H non-compact-symmetric space and obtained by compactifying supergravity to D=3 admit a closed form general integral depending analytically on a complete set of integration constants. The key point in establishing the integration algorithm is provided by an upper triangular embedding of the solvable Lie algebra associated with U/H into sl(N,R) which is guaranteed to exist for all non-compact symmetric spaces and also for homogeneous special geometries non-corresponding to symmetric spaces. In this context we establish a remarkable relation between the end-points of the time-flow and the properties of the Weyl group. The asymptotic states of the developing Universe are in one-to-one correspondence with the elements of the Weyl group which is a property of the Tits-Satake universality classes and not of their single representatives. Furthermore the Weyl group admits a natural ordering in terms of ℓ, the number of reflections with respect to the simple roots. The direction of time flows is always from the minimal accessible value of ℓ to the maximum one or vice versa.
Huff, K. D.; Bauer, T. H.
2012-08-20
A benchmarking effort was conducted to determine the accuracy of a new analytic generic geology thermal repository model developed at LLNL relative to a more traditional, numerical, lumped parameter technique. The fast-running analytical thermal transport model assumes uniform thermal properties throughout a homogenous storage medium. Arrays of time-dependent heat sources are included geometrically as arrays of line segments and points. The solver uses a source-based linear superposition of closed form analytical functions from each contributing point or line to arrive at an estimate of the thermal evolution of a generic geologic repository. Temperature rise throughout the storage medium is computed as a linear superposition of temperature rises. It is modeled using the MathCAD mathematical engine and is parameterized to allow myriad gridded repository geometries and geologic characteristics [4]. It was anticipated that the accuracy and utility of the temperature field calculated with the LLNL analytical model would provide an accurate 'birds-eye' view in regions that are many tunnel radii away from actual storage units; i.e., at distances where tunnels and individual storage units could realistically be approximated as physical lines or points. However, geometrically explicit storage units, waste packages, tunnel walls and close-in rock are not included in the MathCAD model. The present benchmarking effort therefore focuses on the ability of the analytical model to accurately represent the close-in temperature field. Specifically, close-in temperatures computed with the LLNL MathCAD model were benchmarked against temperatures computed using geometrically-explicit lumped-parameter, repository thermal modeling technique developed over several years at ANL using the SINDAG thermal modeling code [5]. Application of this numerical modeling technique to underground storage of heat generating nuclear waste streams within the proposed YMR Site has been widely reported [6
Escaping or connecting? Characteristics of youth who form close online relationships.
Wolak, Janis; Mitchell, Kimberly J; Finkelhor, David
2003-02-01
We used data from a US national sample of Internet users, ages 10-17 (N=1501), to explore the characteristics of youth who had formed close relationships with people they met on the Internet (n=210). Girls who had high levels of conflict with parents or were highly troubled were more likely than other girls to have close online relationships, as were boys who had low levels of communication with parents or were highly troubled, compared to other boys. Age, race and aspects of Internet use were also related. We know little about the nature or quality of the close online relationships, but youth with these sorts of problems may be more vulnerable to online exploitation and to other possible ill effects of online relationships. At the same time, these relationships may have helpful aspects.
Closed-form solutions and scaling laws for Kerr frequency combs
Renninger, William H.; Rakich, Peter T.
2016-01-01
A single closed-form analytical solution of the driven nonlinear Schrödinger equation is developed, reproducing a large class of the behaviors in Kerr-comb systems, including bright-solitons, dark-solitons, and a large class of periodic wavetrains. From this analytical framework, a Kerr-comb area theorem and a pump-detuning relation are developed, providing new insights into soliton- and wavetrain-based combs along with concrete design guidelines for both. This new area theorem reveals significant deviation from the conventional soliton area theorem, which is crucial to understanding cavity solitons in certain limits. Moreover, these closed-form solutions represent the first step towards an analytical framework for wavetrain formation, and reveal new parameter regimes for enhanced Kerr-comb performance. PMID:27108810
Aerodynamic Lift and Moment Calculations Using a Closed-Form Solution of the Possio Equation
NASA Technical Reports Server (NTRS)
Lin, Jensen; Iliff, Kenneth W.
2000-01-01
In this paper, we present closed-form formulas for the lift and moment coefficients of a lifting surface in two dimensional, unsteady, compressible, subsonic flow utilizing a newly developed explicit analytical solution of the Possio equation. Numerical calculations are consistent with previous numerical tables based on series expansions or ad hoc numerical schemes. More importantly, these formulas lend themselves readily to flutter analysis, compared with the tedious table-look-up schemes currently in use.
NASA Astrophysics Data System (ADS)
Tyagi, Sandeep
A method is given to obtain closed form formulas for the energy and forces for an aggregate of charges interacting via a logarithmic interaction under periodic boundary conditions. The work done here is a generalization of Glasser's results [J. Math. Phys., 15, 188 (1974)] and is obtained with a different and simpler method than that by Stremler [J. Math. Phys., 45, 3584 (2004)]. The simplicity of the formulas derived here makes them extremely convenient in a computer simulation.
A closed-form solution for the price of cross-commodity electricity derivatives
NASA Astrophysics Data System (ADS)
Tsitakis, D.; Xanthopoulos, S.; Yannacopoulos, A. N.
2006-11-01
We present a method for the valuation of two types of cross-commodity electricity options, European spark spread options and locational spread options. Since the underlying assets here are non-tradeable, the methodology of Black-Scholes-Merton cannot be directly applied. Nevertheless, assuming only absence of arbitrage we provide a closed-form analytic formula for the price of the derivatives in the case where the spot prices of the underlying process follow an exponential Ornstein-Uhlenbeck process.
Causality arguments behind closed-form description of air dispersion in the mid-infrared
NASA Astrophysics Data System (ADS)
Zheltikov, A. M.
2017-04-01
We show that a closed-form Sellmeier-equation description of the refractive index of atmospheric air can be extended to the mid- and long-wavelength infrared spectral ranges, where the optical response of air is dominated by molecular rovibrational modes. When written in the form of a Sellmeier-type equation, the formula of air refractivity is shown to be instrumental for the analysis of group-velocity dispersion of atmospheric air, helping identify the regions of broadband anomalous dispersion, where long-distance transmission and soliton pulse compression of high-power mid- and long-wavelength infrared field waveforms are possible.
A closed-form expression of the positional uncertainty for 3D point clouds.
Bae, Kwang-Ho; Belton, David; Lichti, Derek D
2009-04-01
We present a novel closed-form expression of positional uncertainty measured by a near-monostatic and time-of-flight laser range finder with consideration of its measurement uncertainties. An explicit form of the angular variance of the estimated surface normal vector is also derived. This expression is useful for the precise estimation of the surface normal vector and the outlier detection for finding correspondence in order to register multiple three-dimensional point clouds. Two practical algorithms using these expressions are presented: a method for finding optimal local neighbourhood size which minimizes the variance of the estimated normal vector and a resampling method of point clouds.
A closed-form solution for steady-state coupled phloem/xylem flow using the Lambert-W function.
Hall, A J; Minchin, P E H
2013-12-01
A closed-form solution for steady-state coupled phloem/xylem flow is presented. This incorporates the basic Münch flow model of phloem transport, the cohesion model of xylem flow, and local variation in the xylem water potential and lateral water flow along the transport pathway. Use of the Lambert-W function allows this solution to be obtained under much more general and realistic conditions than has previously been possible. Variation in phloem resistance (i.e. viscosity) with solute concentration, and deviations from the Van't Hoff expression for osmotic potential are included. It is shown that the model predictions match those of the equilibrium solution of a numerical time-dependent model based upon the same mechanistic assumptions. The effect of xylem flow upon phloem flow can readily be calculated, which has not been possible in any previous analytical model. It is also shown how this new analytical solution can handle multiple sources and sinks within a complex architecture, and can describe competition between sinks. The model provides new insights into Münch flow by explicitly including interactions with xylem flow and water potential in the closed-form solution, and is expected to be useful as a component part of larger numerical models of entire plants.
Formability models for warm sheet metal forming analysis
NASA Astrophysics Data System (ADS)
Jiang, Sen
Several closed form models for the prediction of strain space sheet metal formability as a function of temperature and strain rate are proposed. The proposed models require only failure strain information from the uniaxial tension test at an elevated temperature setting and failure strain information from the traditionally defined strain space forming limit diagram at room temperature, thereby featuring the advantage of offering a full forming limit description without having to carry out expensive experimental studies for multiple modes of deformation under the elevated temperature. The Power law, Voce, and Johnson-Cook hardening models are considered along with the yield criterions of Hill's 48 and Logan-Hosford yield criteria. Acceptable correlations between the theory and experiment are reported for all the models under a plane strain condition. Among all the proposed models, the model featuring Johnson-Cook hardening model and Logan-Hosford yield behavior (LHJC model) was shown to best correlate with experiment. The sensitivity of the model with respect to various forming parameters is discussed. This work is significant to those aiming to incorporate closed-form formability models directly into numerical simulation programs for the purpose of design and analysis of products manufactured through the warm sheet metal forming process. An improvement based upon Swift's diffuse necking theory, is suggested in order to enhance the reliability of the model for biaxial stretch conditions. Theory relating to this improvement is provided in Appendix B.
A matrix model for Misner universe and closed string tachyons
NASA Astrophysics Data System (ADS)
She, Jian-Huang
2006-01-01
We use D-instantons to probe the geometry of Misner universe, and calculate the world volume field theory action, which is of the 1+0 dimensional form and highly non-local. Turning on closed string tachyons, we see from the deformed moduli space of the D-instantons that the spacelike singularity is removed and the region near the singularity becomes a fuzzy cone, where space and time do not commute. When realized cosmologically there can be controllable trans-planckian effects. And the infinite past is now causally connected with the infinite future, thus also providing a model for big crunch/big bang transition. In the spirit of IKKT matrix theory, we propose that the D-instanton action here provides a holographic description for Misner universe and time is generated dynamically. In addition we show that winding string production from the vacua and instability of D-branes have simple uniform interpretations in this second quantized formalism.
A General Closed-Form Solution for the Lunar Reconnaissance Orbiter (LRO) Antenna Pointing System
NASA Technical Reports Server (NTRS)
Shah, Neerav; Chen, J. Roger; Hashmall, Joseph A.
2010-01-01
antenna orientation. The nominal geometry for the HGA involves an outer gimbal axis that is exactly perpendicular to the inner gimbal axis, and a target direction that is exactly perpendicular to the outer gimbal axis. For this nominal geometry, closed-form solutions of the desired gimbal angles are simple to get for a desired target direction specified in the spacecraft body fame. If the gimbal axes and the antenna boresight are slightly misaligned, the nominal closed-form solution is not sufficiently accurate for computing the gimbal angles needed to point at a target. In this situation, either a general closed-form solution has to be developed for a mechanism with general geometries, or a correction scheme has to be applied to the nominal closed-form solutions. The latter has been adopted for Solar Dynamics Observatory (SDO) as can be seen in Reference 1, and the former has been used for LRO. The advantage of the general closed-form solution is the use of a small number of parameters for the correction of nominal solutions, especially in the regions near singularities. Singularities here refer to cases when the nominal closed-form solutions have two or more solutions. Algorithm complexity, however, is the disadvantage of the general closed-form solution.
New Closed-Form of the Largest Eigenvalue PDF for Max-SNR MIMO System Performances
NASA Astrophysics Data System (ADS)
Letessier, Jonathan; Vrigneau, Baptiste; Rostaing, Philippe; Burel, Gilles
Multiple-input multiple-output (MIMO) maximum-SNR (max-SNR) system employs the maximum ratio combiner (MRC) at the receiver side and the maximum ratio transmitter (MRT) at the transmitter side. Its performances highly depend on MIMO channel characteristics, which vary according to both the number of antennas and their distribution between the transmitter and receiver sides. By using the decomposition of the ordered Wishart distribution in the uncorrelated Rayleigh case, we derived a closed-form expression of the largest eigenvalue probability density function (PDF). The final result yields to an expression form of the PDF where polynomials are multiplied by exponentials; it is worth underlining that, though this form had been previously observed for given couples of antennas, to date no formally-written closed-form was available in the literature for an arbitrary couple. Then, this new expression permits one to quickly and easily get the well known largest eigenvalue PDF and use it to determine the binary error probability (BEP) of the max-SNR.
Closed form and geometric algorithms for real-time control of an avatar
Semwall, S.K.; Hightower, R.; Stansfield, S.
1995-12-31
In a virtual environment with multiple participants, it is necessary that the user`s actions be replicated by synthetic human forms. Whole body digitizers would be the most realistic solution for capturing the individual participant`s human form, however the best of the digitizers available are not interactive and are therefore not suitable for real-time interaction. Usually, a limited number of sensors are used as constraints on the synthetic human form. Inverse kinematics algorithms are applied to satisfy these sensor constraints. These algorithms result in slower interaction because of their iterative nature, especially when there are a large number of participants. To support real-time interaction in a virtual environment, there is a need to generate closed for solutions and fast searching algorithms. In this paper, a new closed form solution for the arms (and legs) is developed using two magnetic sensors. In developing this solution, we use the biomechanical relationship between the lower arm and the upper arm to provide an analytical, non-iterative solution, We have also outlined a solution for the whole human body by using up to ten magnetic sensors to break the human skeleton into smaller kinematic chains. In developing our algorithms, we use the knowledge of natural body postures to generate faster solutions for real-time interaction.
NASA Astrophysics Data System (ADS)
Xu, T. F.; Xing, Y. F.
2016-12-01
This article presents closed-form solutions for the frequency analysis of rectangular functionally graded material (FGM) thin plates subjected to initially in-plane loads and with an elastic foundation. Based on classical thin plate theory, the governing differential equations are derived using Hamilton's principle. A neutral surface is used to eliminate stretching-bending coupling in FGM plates on the basis of the assumption of constant Poisson's ratio. The resulting governing equation of FGM thin plates has the same form as homogeneous thin plates. The separation-of-variables method is adopted to obtain solutions for the free vibration problems of rectangular FGM thin plates with separable boundary conditions, including, for example, clamped plates. The obtained normal modes and frequencies are in elegant closed forms, and present formulations and solutions are validated by comparing present results with those in the literature and finite element method results obtained by the authors. A parameter study reveals the effects of the power law index n and aspect ratio a/ b on frequencies.
a Weighted Closed-Form Solution for Rgb-D Data Registration
NASA Astrophysics Data System (ADS)
Vestena, K. M.; Dos Santos, D. R.; Oilveira, E. M., Jr.; Pavan, N. L.; Khoshelham, K.
2016-06-01
Existing 3D indoor mapping of RGB-D data are prominently point-based and feature-based methods. In most cases iterative closest point (ICP) and its variants are generally used for pairwise registration process. Considering that the ICP algorithm requires an relatively accurate initial transformation and high overlap a weighted closed-form solution for RGB-D data registration is proposed. In this solution, we weighted and normalized the 3D points based on the theoretical random errors and the dual-number quaternions are used to represent the 3D rigid body motion. Basically, dual-number quaternions provide a closed-form solution by minimizing a cost function. The most important advantage of the closed-form solution is that it provides the optimal transformation in one-step, it does not need to calculate good initial estimates and expressively decreases the demand for computer resources in contrast to the iterative method. Basically, first our method exploits RGB information. We employed a scale invariant feature transformation (SIFT) for extracting, detecting, and matching features. It is able to detect and describe local features that are invariant to scaling and rotation. To detect and filter outliers, we used random sample consensus (RANSAC) algorithm, jointly with an statistical dispersion called interquartile range (IQR). After, a new RGB-D loop-closure solution is implemented based on the volumetric information between pair of point clouds and the dispersion of the random errors. The loop-closure consists to recognize when the sensor revisits some region. Finally, a globally consistent map is created to minimize the registration errors via a graph-based optimization. The effectiveness of the proposed method is demonstrated with a Kinect dataset. The experimental results show that the proposed method can properly map the indoor environment with an absolute accuracy around 1.5% of the travel of a trajectory.
A Closed-Form Solution to Retinex with Nonlocal Texture Constraints.
Zhao, Qi; Tan, Ping; Dai, Qiang; Shen, Li; Wu, Enhua; Lin, Stephen
2012-07-01
We propose a method for intrinsic image decomposition based on retinex theory and texture analysis. While most previous methods approach this problem by analyzing local gradient properties, our technique additionally identifies distant pixels with the same reflectance through texture analysis, and uses these nonlocal reflectance constraints to significantly reduce ambiguity in decomposition. We formulate the decomposition problem as the minimization of a quadratic function which incorporates both the retinex constraint and our nonlocal texture constraint. This optimization can be solved in closed form with the standard conjugate gradient algorithm. Extensive experimentation with comparisons to previous techniques validate our method in terms of both decomposition accuracy and runtime efficiency.
A closed form solution to the one-ball geolocation problem
NASA Astrophysics Data System (ADS)
Nelson, D. J.; Townsend, J. L.
2016-05-01
We address the problem of determining the source location of an electromagnetic signal from the signal received by one or more moving receivers. We base our process on cross-spectral methods that were developed in the early 1980's for analysis and demodulation/despreading of communication and spread spectrum signals and were later applied to speech processing and speech enhancement. In this article, we expand the concept of robust polynomial tracking, which we demonstrate may be used to solve for the emitter location in closed form. This is accomplished by generating and solving a system of equations representing curves, each of which passes through the emitter location.
Comment on ‘Special-case closed form of the Baker-Campbell-Hausdorff formula’
NASA Astrophysics Data System (ADS)
Lo, C. F.
2016-05-01
Recently Van-Brunt and Visser (2015 J. Phys. A: Math. Theor. 48 225207) succeeded in explicitly evaluating the Baker-Campbell-Hausdorff (BCH) expansion series for the noncommuting operators X and Y, provided that the two operators satisfy the commutation relation: [X,Y]={uX}+{vY}+{cI}, and the operator I commutes with both of them. In this comment we show that the closed-form BCH formula of this special case can be straightforwardly derived by the means of the Wei-Norman theorem and no summation of the infinite series is needed.
Propagation of sound waves through a linear shear layer - A closed form solution
NASA Technical Reports Server (NTRS)
Scott, J. N.
1978-01-01
Closed form solutions are presented for sound propagation from a line source in or near a shear layer. The analysis is exact for all frequencies and is developed assuming a linear velocity profile in the shear layer. This assumption allows the solution to be expressed in terms of parabolic cylinder functions. The solution is presented for a line monopole source first embedded in the uniform flow and then in the shear layer. Solutions are also discussed for certain types of dipole and quadrupole sources. Asymptotic expansions of the exact solutions for small and large values of Strouhal number give expressions which correspond to solutions previously obtained for these limiting cases.
Propagation of sound waves through a linear shear layer: A closed form solution
NASA Technical Reports Server (NTRS)
Scott, J. N.
1978-01-01
Closed form solutions are presented for sound propagation from a line source in or near a shear layer. The analysis was exact for all frequencies and was developed assuming a linear velocity profile in the shear layer. This assumption allowed the solution to be expressed in terms of parabolic cyclinder functions. The solution is presented for a line monopole source first embedded in the uniform flow and then in the shear layer. Solutions are also discussed for certain types of dipole and quadrupole sources. Asymptotic expansions of the exact solutions for small and large values of Strouhal number gave expressions which correspond to solutions previously obtained for these limiting cases.
Closed-form expressions for the Dirac-Coulomb radial rt integrals
NASA Astrophysics Data System (ADS)
Bessis, N.; Bessis, G.; Roux, D.
1985-10-01
A novel procedure is devised in order to obtain closed-form expressions of the Dirac-Coulomb radial rt integrals in terms of the Dirac energy ɛ=\\{1+Z2α2/[v+(k2-Z2 α2)1/2]2\\}-1/2, where v=n-||k||, and of the Dirac quantum number k=(-1)j+l+1/2(j+(1/2)). In this procedure, well adapted for symbolic computation, the fundamental array of the rt radial integrals is obtained from the rt-1 array.
Intermediate Fidelity Closed Brayton Cycle Power Conversion Model
NASA Technical Reports Server (NTRS)
Lavelle, Thomas M.; Khandelwal, Suresh; Owen, Albert K.
2006-01-01
This paper describes the implementation of an intermediate fidelity model of a closed Brayton Cycle power conversion system (Closed Cycle System Simulation). The simulation is developed within the Numerical Propulsion Simulation System architecture using component elements from earlier models. Of particular interest, and power, is the ability of this new simulation system to initiate a more detailed analysis of compressor and turbine components automatically and to incorporate the overall results into the general system simulation.
NASA Technical Reports Server (NTRS)
Hanks, Brantley R.; Skelton, Robert E.
1991-01-01
Vibration in modern structural and mechanical systems can be reduced in amplitude by increasing stiffness, redistributing stiffness and mass, and/or adding damping if design techniques are available to do so. Linear Quadratic Regulator (LQR) theory in modern multivariable control design, attacks the general dissipative elastic system design problem in a global formulation. The optimal design, however, allows electronic connections and phase relations which are not physically practical or possible in passive structural-mechanical devices. The restriction of LQR solutions (to the Algebraic Riccati Equation) to design spaces which can be implemented as passive structural members and/or dampers is addressed. A general closed-form solution to the optimal free-decay control problem is presented which is tailored for structural-mechanical system. The solution includes, as subsets, special cases such as the Rayleigh Dissipation Function and total energy. Weighting matrix selection is a constrained choice among several parameters to obtain desired physical relationships. The closed-form solution is also applicable to active control design for systems where perfect, collocated actuator-sensor pairs exist.
A closed-form solution to tensor voting: theory and applications.
Wu, Tai-Pang; Yeung, Sai-Kit; Jia, Jiaya; Tang, Chi-Keung; Medioni, Gérard
2012-08-01
We prove a closed-form solution to tensor voting (CFTV): Given a point set in any dimensions, our closed-form solution provides an exact, continuous, and efficient algorithm for computing a structure-aware tensor that simultaneously achieves salient structure detection and outlier attenuation. Using CFTV, we prove the convergence of tensor voting on a Markov random field (MRF), thus termed as MRFTV, where the structure-aware tensor at each input site reaches a stationary state upon convergence in structure propagation. We then embed structure-aware tensor into expectation maximization (EM) for optimizing a single linear structure to achieve efficient and robust parameter estimation. Specifically, our EMTV algorithm optimizes both the tensor and fitting parameters and does not require random sampling consensus typically used in existing robust statistical techniques. We performed quantitative evaluation on its accuracy and robustness, showing that EMTV performs better than the original TV and other state-of-the-art techniques in fundamental matrix estimation for multiview stereo matching. The extensions of CFTV and EMTV for extracting multiple and nonlinear structures are underway.
M.T. Peters; R.C. Ewing
2006-06-22
There are two compelling reasons for understanding source term and near-field processes in a radioactive waste geologic repository. First, almost all of the radioactivity is initially in the waste form, mainly in the spent nuclear fuel (SNF) or nuclear waste glass. Second, over long periods, after the engineered barriers are degraded, the waste form is a primary control on the release of radioactivity. Thus, it is essential to know the physical and chemical state of the waste form after hundreds of thousands of years. The United States Department of Energy's Yucca Mountain Repository Program has initiated a long-term program to develop a basic understanding of the fundamental mechanisms of radionuclide release and a quantification of the release as repository conditions evolve over time. Specifically, the research program addresses four critical areas: (a) SNF dissolution mechanisms and rates; (b) formation and properties of U{sup 6+}-secondary phases; (c) waste form-waste package interactions in the near-field; and (d) integration of in-package chemical and physical processes. The ultimate goal is to integrate the scientific results into a larger scale model of source term and near-field processes. This integrated model will be used to provide a basis for understanding the behavior of the source term over long time periods (greater than 10{sup 5} years). Such a fundamental and integrated experimental and modeling approach to source term processes can also be readily applied to development of advanced waste forms as part of a closed nuclear fuel cycle. Specifically, a fundamental understanding of candidate waste form materials stability in high temperature/high radiation environments and near-field geochemical/hydrologic processes could enable development of advanced waste forms ''tailored'' to specific geologic settings.
NASA Astrophysics Data System (ADS)
Sadegh, M.; Vrugt, J. A.; Gupta, H. V.; Xu, C.
2016-04-01
The flow duration curve is a signature catchment characteristic that depicts graphically the relationship between the exceedance probability of streamflow and its magnitude. This curve is relatively easy to create and interpret, and is used widely for hydrologic analysis, water quality management, and the design of hydroelectric power plants (among others). Several mathematical expressions have been proposed to mimic the FDC. Yet, these efforts have not been particularly successful, in large part because available functions are not flexible enough to portray accurately the functional shape of the FDC for a large range of catchments and contrasting hydrologic behaviors. Here, we extend the work of Vrugt and Sadegh (2013) and introduce several commonly used models of the soil water characteristic as new class of closed-form parametric expressions for the flow duration curve. These soil water retention functions are relatively simple to use, contain between two to three parameters, and mimic closely the empirical FDCs of 430 catchments of the MOPEX data set. We then relate the calibrated parameter values of these models to physical and climatological characteristics of the watershed using multivariate linear regression analysis, and evaluate the regionalization potential of our proposed models against those of the literature. If quality of fit is of main importance then the 3-parameter van Genuchten model is preferred, whereas the 2-parameter lognormal, 3-parameter GEV and generalized Pareto models show greater promise for regionalization.
Trapping Open and Closed Forms of FitE-A Group III Periplasmic Binding Protein
Shi, R.; Proteau, A; Wagner, J; Cui, Q; Purisima, E; Matte, A; Cygler, M
2009-01-01
Periplasmic binding proteins (PBPs) are essential components of bacterial transport systems, necessary for bacterial growth and survival. The two-domain structures of PBPs are topologically classified into three groups based on the number of crossovers or hinges between the globular domains: group I PBPs have three connections, group II have two, and group III have only one. Although a large number of structures for group I or II PBPs are known, fewer group III PBPs have been structurally characterized. Group I and II PBPs exhibit significant domain motions during transition from the unbound to ligand-bound form, however, no large conformational changes have been observed to date in group III PBPs. We have solved the crystal structure of a periplasmic binding protein FitE, part of an iron transport system, fit, recently identified in a clinical E. coli isolate. The structure, determined at 1.8 {angstrom} resolution, shows that FitE is a group III PBP containing a single {alpha}-helix bridging the two domains. Among the individual FitE molecules present in two crystal forms we observed three different conformations (open, closed, intermediate). Our crystallographic and molecular dynamics results strongly support the notion that group III PBPs also adopt the same Venus flytrap mechanism as do groups I and II PBPs. Unlike other group III PBPs, FitE forms dimers both in solution and in the crystals. The putative siderophore binding pocket is lined with arginine residues, suggesting an anionic nature of the iron-containing siderophore.
Closed-form expression for the Goos-Hänchen lateral displacement
NASA Astrophysics Data System (ADS)
Araújo, Manoel P.; De Leo, Stefano; Maia, Gabriel G.
2016-02-01
The Artmann formula provides an accurate determination of the Goos-Hänchen lateral displacement in terms of the light wavelength, refractive index, and incidence angle. In the total reflection region, this formula is widely used in the literature and confirmed by experiments. Nevertheless, for incidence at critical angle, it tends to infinity and numerical calculations are needed to reproduce the experimental data. In this paper, we overcome the divergence problem at critical angle and find, for Gaussian beams, a closed formula in terms of modified Bessel functions of the first kind. The formula is in excellent agreement with numerical calculations and reproduces, for incidence angles greater than critical ones, the Artmann formula. The closed form also allows one to understand how the breaking of symmetry in the angular distribution is responsible for the difference between measurements done by considering the maximum and the mean value of the beam intensity. The results obtained in this study clearly show the Goos-Hänchen lateral displacement dependence on the angular distribution shape of the incoming beam. Finally, we also present a brief comparison with experimental data and other analytical formulas found in the literature.
Closed Form Equations for the Preliminary Design of a Heat-Pipe-Cooled Leading Edge
NASA Technical Reports Server (NTRS)
Glass, David E.
1998-01-01
A set of closed form equations for the preliminary evaluation and design of a heat-pipe-cooled leading edge is presented. The set of equations can provide a leading-edge designer with a quick evaluation of the feasibility of using heat-pipe cooling. The heat pipes can be embedded in a metallic or composite structure. The maximum heat flux, total integrated heat load, and thermal properties of the structure and heat-pipe container are required input. The heat-pipe operating temperature, maximum surface temperature, heat-pipe length, and heat pipe-spacing can be estimated. Results using the design equations compared well with those from a 3-D finite element analysis for both a large and small radius leading edge.
Closed-form expressions to fit data obtained with a multipass Fabry-Perot interferometer.
Boukari, H; Palik, E D; Gammon, R W
1995-01-01
We have studied the effect of a multipass Fabry-Perot interferometer (FP) on a scattering line. Here we describe a method that we applied to derive a closed-form expression for a line shape obtained with an ideal, multipass FP. The method reduces the convolution problem between the multipass function and the scattering line to the corresponding single-pass problem. We illustrate the method with a Lorentzian and a damped-harmonic-oscillator line passed through a single-, triple-, and quintuple-pass FP. Furthermore we have applied the method to a study of the effect of the collecting pinhole on a sharp line obtained by multipassing. We show how we used these functions to fit the complete spectra obtained with a single- and triple-pass FP.
Krishnamoorthy, K; Lee, Meesook; Zhang, Dan
2017-02-01
Approximate closed-form confidence intervals (CIs) for estimating the difference, relative risk, odds ratio, and linear combination of proportions are proposed. These CIs are developed using the fiducial approach and the modified normal-based approximation to the percentiles of a linear combination of independent random variables. These confidence intervals are easy to calculate as the computation requires only the percentiles of beta distributions. The proposed confidence intervals are compared with the popular score confidence intervals with respect to coverage probabilities and expected widths. Comparison studies indicate that the proposed confidence intervals are comparable with the corresponding score confidence intervals, and better in some cases, for all the problems considered. The methods are illustrated using several examples.
Closed form analysis of a gamma, back-to-back free displacer Stirling engine
Lewis, K.L.; Kilgour, D.B.; Lazarides, Y.G.; Rallis, C.J.
1983-08-01
A back-to-back, free displacer, gamma type Stirling engine has been designed and is currently under manufacture and development at the University of the Witwatersrand. This paper presents a simple idealized analysis for such an engine. It involves the coupling together of the thermodynamic and mechanical equations, and by the use of classical control and vibration theory, closed form solutions are obtained. This work follows up on previous methods of analysis developed by Berchowitz, WyattMair and Goldberg for similar types of engines. A numerical application of the analysis has been carried out for the design in order to evaluate the operating frequency, phase displacements, amplitude of oscillation and basic output power. Performance characteristics are obtained and detailed in the paper. The analysis has provided analytic proof of the viability of the proposed engine configuration, highlighted weak areas and provided a background to higher order analysis. A programme of experimental validation is under way.
Closed-form Maker fringe formulas for poled polymer thin films in multilayer structures.
Park, Dong Hun; Herman, Warren N
2012-01-02
We report new closed-form expressions for Maker fringes of anisotropic and absorbing poled polymer thin films in multilayer structures that include back reflections of both fundamental and second-harmonic waves. The expressions, based on boundary conditions at each interface, can be applied to multilayer structures containing a buffer and a transparent conducting oxide layer, which might enhance multiple reflections of fundamental and second-harmonic waves inside a nonlinear thin film layer. This formulation facilitates Maker fringe analysis for a sample containing additional multilayer structures on either side of a poled polymer thin film. Experimental data and numerical simulations are given to indicate the importance of inclusion of such a reflective layer in analyses for reliable characterization of second-harmonic tensor elements.
Stresses in adhesively bonded joints: A closed form solution. [plate theory
NASA Technical Reports Server (NTRS)
Delale, F.; Erdogan, F.; Aydinoglu, M. N.
1980-01-01
The plane strain of adhesively bonded structures which consist of two different orthotropic adherents is considered. Assuming that the thicknesses of the adherends are constant and are small in relation to the lateral dimensions of the bonded region, the adherends are treated as plates. The transverse shear effects in the adherends and the in-plane normal strain in the adhesive are taken into account. The problem is reduced to a system of differential equations for the adhesive stresses which is solved in closed form. A single lap joint and a stiffened plate under various loading conditions are considered as examples. To verify the basic trend of the solutions obtained from the plate theory a sample problem is solved by using the finite element method and by treating the adherends and the adhesive as elastic continua. The plate theory not only predicts the correct trend for the adhesive stresses but also gives rather surprisingly accurate results.
Adaptive Filtering for Large Space Structures: A Closed-Form Solution
NASA Technical Reports Server (NTRS)
Rauch, H. E.; Schaechter, D. B.
1985-01-01
In a previous paper Schaechter proposes using an extended Kalman filter to estimate adaptively the (slowly varying) frequencies and damping ratios of a large space structure. The time varying gains for estimating the frequencies and damping ratios can be determined in closed form so it is not necessary to integrate the matrix Riccati equations. After certain approximations, the time varying adaptive gain can be written as the product of a constant matrix times a matrix derived from the components of the estimated state vector. This is an important savings of computer resources and allows the adaptive filter to be implemented with approximately the same effort as the nonadaptive filter. The success of this new approach for adaptive filtering was demonstrated using synthetic data from a two mode system.
An approximate closed-form solution for lead lag damping of rotor blades in hover
NASA Technical Reports Server (NTRS)
Peters, D. A.
1975-01-01
Simple stability methods are used to derive an approximate, closed-form expression for the lead-lag damping of rotor blades in hover. Destabilizing terms are shown to be a result of two dynamic mechanisms. First, the destabilizing aerodynamic forces that can occur when blade lift is higher than a critical value are maximized when the blade motion is in a straight line equidistant from the blade chord and the average direction of the air flow velocity. This condition occurs when the Coriolis terms vanish and when the elastic coupling terms align the blade motion with this least stable direction. Second, the nonconservative stiffness terms that result from pitch-flap or pitch-lag coupling can add or subtract energy from the system depending upon whether the motion of the blade tip is clockwise or counterclockwise.
NASA Technical Reports Server (NTRS)
Wu, Kinwah; Chanmugam, G.; Shaviv, G.
1994-01-01
We present, for the first time, a closed integral-form solution to the accretion shock structures for the case where the cooling is due to optically thin bremsstrahlung emission and a series of power-law cooling functions of density and temperature. Our results can provide useful checks on numerical calculations and simple accurate estimates for valuable parameters such as the shock height. For the case where the cooling rate j = (2/3)Arho(exp 2)(P/rho)(exp 1/2)(1 + epsilon (sub s)(P/P(sub s)(exp alpha)(rho(sub s)/rho)(exp beta)), we find that a substantial amount of the accretion energy is released at the base of the accretion shock in the form of bremsstrahlung radiation. This implies that for a cyclotron-dominated shock (qualitatively given by alpha = 2.0, beta = 3.85, and epsilon(sub s) is much greater than 1), bremsstrahlung cooling still plays a crucial role in determining the shock structure. Our results are shown to be consistent with detailed numerical calculations.
Milani, Gabriele E-mail: gabriele.milani@polimi.it; Hanel, Thomas; Donetti, Raffaella; Milani, Federico
2015-03-10
The basic reaction scheme due to Han and co-workers for NR vulcanized with sulphur is adopted and modified taking into account the single contributions of the different accelerators, focusing in particular on some experimental data ad hoc obtained at Pirelli’s laboratories, where NR was vulcanized at different temperatures (from 150 to 180 °C) and concentrations of sulphur, using TBBS and DPG in the mixture as co-agents. Typically, the chain reactions are initiated by the formation of macro-compounds that are responsible of the formation of the unmatured crosslinked polymer. This first reaction depends on the reciprocal concentrations of all components and their chemical nature. In presence of two accelerators, it was considered that the reactions between each single accelerator and the NR raw material occur in parallel, making the reasonable assumption that there are no mutual reactions between the two accelerators. From the kinetic scheme adopted, a closed form solution was found for the crosslink density, with the only limitation that the induction period is excluded from computations. Even kinetic constants are evaluated in closed form, avoiding a numerically demanding least-squares best fitting on rheometer experimental data. Two series of experiments available, relying into rheometer curves at different temperatures and different concentrations of sulphur and accelerator, are utilized to evaluate the fitting capabilities of the mathematical model. Very good agreement between numerical output and experimental data is experienced in all cases analysed.
17 CFR 274.11a-1 - Form N-2, registration statement of closed end management investment companies.
Code of Federal Regulations, 2010 CFR
2010-04-01
... statement of closed end management investment companies. 274.11a-1 Section 274.11a-1 Commodity and... management investment companies. This form shall be used as the registration statement to be filed pursuant to section 8(b) of the Investment Company Act of 1940 by closed end management investment...
17 CFR 274.11a-1 - Form N-2, registration statement of closed end management investment companies.
Code of Federal Regulations, 2011 CFR
2011-04-01
... statement of closed end management investment companies. 274.11a-1 Section 274.11a-1 Commodity and... management investment companies. This form shall be used as the registration statement to be filed pursuant to section 8(b) of the Investment Company Act of 1940 by closed end management investment...
Finite Elements Modeling in Diagnostics of Small Closed Pneumothorax.
Lorkowski, J; Mrzygłód, M; Grzegorowska, O
2015-01-01
Posttraumatic pneumothorax still remains to be a serious clinical problem and requires a comprehensive diagnostic and monitoring during treatment. The aim of this paper is to present a computer method of modeling of small closed pneumothorax. Radiological images of 34 patients of both sexes with small closed pneumothorax were taken into consideration. The control group consisted of X-rays of 22 patients treated because of tension pneumothorax. In every single case the model was correlated with the clinical manifestations. The procedure of computational rapid analysis (CRA) for in silico analysis of surgical intervention was introduced. It included implementation of computerize tomography images and their automatic conversion into 3D finite elements model (FEM). In order to segmentize the 3D model, an intelligent procedure of domain recognition was used. In the final step, a computer simulation project of fluid-structure interaction was built, using the ANSYS\\Workbench environment of multi-physics analysis. The FEM model and computer simulation project were employed in the analysis in order to optimize surgical intervention. The model worked out well and was compatible with the clinical manifestations of pneumothorax. We conclude that the created FEM model is a promising tool for facilitation of diagnostic procedures and prognosis of treatment in the case of small closed pneumothorax.
Del Rey, P
1971-12-01
40 college women performed a modification of the classical fencing lunge against 2 laterally-arranged targets, under closed and open environmental conditions. Form (rating scale), accuracy (proximity to target center), and response latency were taken to measure the effects of video-taped feedback (VT). Administration of VT with specific instructions to direct S's attention to parts of the display resulted in closer approximation of the externally-imposed form, higher accuracy, and shorter response latency. Performing the skill in the closed environmental condition resulted in less deviation from the imposed form, higher accuracy scores, and longer response latency. No significant correlations were found between imposed form and accuracy.
Hencky's model for elastomer forming process
NASA Astrophysics Data System (ADS)
Oleinikov, A. A.; Oleinikov, A. I.
2016-08-01
In the numerical simulation of elastomer forming process, Henckys isotropic hyperelastic material model can guarantee relatively accurate prediction of strain range in terms of large deformations. It is shown, that this material model prolongate Hooke's law from the area of infinitesimal strains to the area of moderate ones. New representation of the fourth-order elasticity tensor for Hencky's hyperelastic isotropic material is obtained, it possesses both minor symmetries, and the major symmetry. Constitutive relations of considered model is implemented into MSC.Marc code. By calculating and fitting curves, the polyurethane elastomer material constants are selected. Simulation of equipment for elastomer sheet forming are considered.
Similarity measure learning in closed-form solution for image classification.
Chen, Jing; Tang, Yuan Yan; Chen, C L Philip; Fang, Bin; Shang, Zhaowei; Lin, Yuewei
2014-01-01
Adopting a measure is essential in many multimedia applications. Recently, distance learning is becoming an active research problem. In fact, the distance is the natural measure for dissimilarity. Generally, a pairwise relationship between two objects in learning tasks includes two aspects: similarity and dissimilarity. The similarity measure provides different information for pairwise relationships. However, similarity learning has been paid less attention in learning problems. In this work, firstly, we propose a general framework for similarity measure learning (SML). Additionally, we define a generalized type of correlation as a similarity measure. By a set of parameters, generalized correlation provides flexibility for learning tasks. Based on this similarity measure, we present a specific algorithm under the SML framework, called correlation similarity measure learning (CSML), to learn a parameterized similarity measure over input space. A nonlinear extension version of CSML, kernel CSML, is also proposed. Particularly, we give a closed-form solution avoiding iterative search for a local optimal solution in the high-dimensional space as the previous work did. Finally, classification experiments have been performed on face databases and a handwritten digits database to demonstrate the efficiency and reliability of CSML and KCSML.
Application of closed-form solutions to a mesh point field in silicon solar cells
NASA Technical Reports Server (NTRS)
Lamorte, M. F.
1985-01-01
A computer simulation method is discussed that provides for equivalent simulation accuracy, but that exhibits significantly lower CPU running time per bias point compared to other techniques. This new method is applied to a mesh point field as is customary in numerical integration (NI) techniques. The assumption of a linear approximation for the dependent variable, which is typically used in the finite difference and finite element NI methods, is not required. Instead, the set of device transport equations is applied to, and the closed-form solutions obtained for, each mesh point. The mesh point field is generated so that the coefficients in the set of transport equations exhibit small changes between adjacent mesh points. Application of this method to high-efficiency silicon solar cells is described; and the method by which Auger recombination, ambipolar considerations, built-in and induced electric fields, bandgap narrowing, carrier confinement, and carrier diffusivities are treated. Bandgap narrowing has been investigated using Fermi-Dirac statistics, and these results show that bandgap narrowing is more pronounced and that it is temperature-dependent in contrast to the results based on Boltzmann statistics.
Efficient dynamic modeling of manipulators containing closed kinematic loops
NASA Astrophysics Data System (ADS)
Ferretti, Gianni; Rocco, Paolo
An approach to efficiently solve the forward dynamics problem for manipulators containing closed chains is proposed. The two main distinctive features of this approach are: the dynamics of the equivalent open loop tree structures (any closed loop can be in general modeled by imposing some additional kinematic constraints to a suitable tree structure) is computed through an efficient Newton Euler formulation; the constraint equations relative to the most commonly adopted closed chains in industrial manipulators are explicitly solved, thus, overcoming the redundancy of Lagrange's multipliers method while avoiding the inefficiency due to a numerical solution of the implicit constraint equations. The constraint equations considered for an explicit solution are those imposed by articulated gear mechanisms and planar closed chains (pantograph type structures). Articulated gear mechanisms are actually used in all industrial robots to transmit motion from actuators to links, while planar closed chains are usefully employed to increase the stiffness of the manipulators and their load capacity, as well to reduce the kinematic coupling of joint axes. The accuracy and the efficiency of the proposed approach are shown through a simulation test.
Model for scattered ion fractions based on equality in the close encounter
NASA Astrophysics Data System (ADS)
Rabalais, J. Wayne; Chen, Jie-Nan; Kumar, R.; Narayana, M.
1985-10-01
A model is developed for electronic transitions in KeV ion/surface collisions which considers Auger and resonant transitions along the ion trajectory and electron promotions in the quasi-diatomic molecule formed in the close encounter. Application to Ne + scattering from Mg allows determination of ionization and neutralization probabilities as a function of the distance of closest approach.
Design of a radio telescope surface segment actuator based on a form-closed eccentric cam
NASA Astrophysics Data System (ADS)
Smith, David R.
2014-07-01
As radio telescopes have reached larger diameters and higher frequencies, it is typically not possible to meet their surface accuracy specifications using passive homology-based designs. The most common solution to this problem in the current generation of large, high-frequency radio telescopes is to employ a system of linear actuators to correct the surface shape of the primary reflector. The exact specifications of active surface actuators vary with the telescope. However, they have many common features, some of which drive their design. In general, these actuators must provide precise and repeatable positioning under significant loads during operation and they must withstand even higher loads for survival conditions. For general safety, they typically must hold position in the event of a power failure and must incorporate position limits, whether electrical, mechanical, or both. Because the number of actuators is generally high for large active surfaces (hundreds or even thousands of actuators), they must also be reliable and of reasonable individual cost. Finally, for maximum flexibility in their installation, they must be compact. This paper presents a concept for an active surface actuator based on a form-closed eccentric cam (kinematically, a Scotch Yoke mechanism). Such a design is limited in stroke, but offers potential advantages in terms of manufacture, compactness, measurement, and survival loading. The paper demonstrates that some of the expected advantages cannot be practically realized, due to dimensions that are driven by survival loading conditions. As a result, this concept is likely to offer an advantage over conventional screw-type actuators only for cases where actuator runaway and stall are the driving considerations.
Simscape Modeling of a Custom Closed-Volume Tank
NASA Technical Reports Server (NTRS)
Fischer, Nathaniel P.
2015-01-01
The library for Mathworks Simscape does not currently contain a model for a closed volume fluid tank where the ullage pressure is variable. In order to model a closed-volume variable ullage pressure tank, it was necessary to consider at least two separate cases: a vertical cylinder, and a sphere. Using library components, it was possible to construct a rough model for the cylindrical tank. It was not possible to construct a model for a spherical tank, using library components, due to the variable area. It was decided that, for these cases, it would be preferable to create a custom library component to represent each case, using the Simscape language. Once completed, the components were added to models, where filling and draining the tanks could be simulated. When the models were performing as expected, it was necessary to generate code from the models and run them in Trick (a real-time simulation program). The data output from Trick was then compared to the output from Simscape and found to be within acceptable limits.
NASA Astrophysics Data System (ADS)
Kassinos, S. C.
2000-11-01
A closed-form solution for the evolution of one-point statistics is derived for the case of initially two-dimensional three-component (2D-3C) homogeneous turbulence deformed by rapid shear in a rotating frame. Cases with and without stratification are considered. Except for small total shear, the analytical result is shown to be in good agreement with the numerical solution of the governing equations, linearized for rapid distortions, and solved for the more general initial case of 3D-3C isotropic homogeneous turbulence. Based on this agreement, we show that the closed-from solution provides insight into the stabilizing and destabilizing effects of frame rotation on homogeneous stratified shear flow, and provides a useful reference point for the one-point modeling of rotated and stratified shear flows. This analysis provides insights on the stability of stratified homogeneous shear flows that are missed by the standard two-dimensional two-component (2D-2C) treatment of stability issues in these flows.
Code of Federal Regulations, 2010 CFR
2010-07-01
... 34 Education 2 2010-07-01 2010-07-01 false Model forms. 300.509 Section 300.509 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION ASSISTANCE TO STATES FOR THE EDUCATION OF CHILDREN WITH DISABILITIES Procedural Safeguards Due...
Wu, Sangwook; Lee, Chang Jun; Pedersen, Lee G
2009-04-01
We test a hypothesis that the closed form of the C2 domain of coagulation factor V is more stable than the open form in an aqueous environment using a two-dimensional free-energy calculation with a simple dielectric solvent model. Our result shows that while the free-energy difference between two forms is small, favoring the closed form, a two-dimensional free-energy surface (FES) reveals that a transition state (1.53 kcal/mol) exists between the two conformations. By mapping the one-dimensional order parameter DeltaQ onto the two-dimensional FES, we search the conformational change path with the highest Boltzmann weighting factor between the closed and open form of the factor V C2 domain. The predicted transition path from the closed to open form is not that of simple side chain movements, but instead concerted movements of several loops. We also present a one-dimensional free-energy profile using a collective order parameter, which in a coarse manner locates the energy barriers found on the two-dimensional FES.
Enabling comparative modeling of closely related genomes: Example genus Brucella
Faria, José P.; Edirisinghe, Janaka N.; Davis, James J.; ...
2014-03-08
For many scientific applications, it is highly desirable to be able to compare metabolic models of closely related genomes. In this study, we attempt to raise awareness to the fact that taking annotated genomes from public repositories and using them for metabolic model reconstructions is far from being trivial due to annotation inconsistencies. We are proposing a protocol for comparative analysis of metabolic models on closely related genomes, using fifteen strains of genus Brucella, which contains pathogens of both humans and livestock. This study lead to the identification and subsequent correction of inconsistent annotations in the SEED database, as wellmore » as the identification of 31 biochemical reactions that are common to Brucella, which are not originally identified by automated metabolic reconstructions. We are currently implementing this protocol for improving automated annotations within the SEED database and these improvements have been propagated into PATRIC, Model-SEED, KBase and RAST. This method is an enabling step for the future creation of consistent annotation systems and high-quality model reconstructions that will support in predicting accurate phenotypes such as pathogenicity, media requirements or type of respiration.« less
NASA Astrophysics Data System (ADS)
Allphin, Devin
Computational fluid dynamics (CFD) solution approximations for complex fluid flow problems have become a common and powerful engineering analysis technique. These tools, though qualitatively useful, remain limited in practice by their underlying inverse relationship between simulation accuracy and overall computational expense. While a great volume of research has focused on remedying these issues inherent to CFD, one traditionally overlooked area of resource reduction for engineering analysis concerns the basic definition and determination of functional relationships for the studied fluid flow variables. This artificial relationship-building technique, called meta-modeling or surrogate/offline approximation, uses design of experiments (DOE) theory to efficiently approximate non-physical coupling between the variables of interest in a fluid flow analysis problem. By mathematically approximating these variables, DOE methods can effectively reduce the required quantity of CFD simulations, freeing computational resources for other analytical focuses. An idealized interpretation of a fluid flow problem can also be employed to create suitably accurate approximations of fluid flow variables for the purposes of engineering analysis. When used in parallel with a meta-modeling approximation, a closed-form approximation can provide useful feedback concerning proper construction, suitability, or even necessity of an offline approximation tool. It also provides a short-circuit pathway for further reducing the overall computational demands of a fluid flow analysis, again freeing resources for otherwise unsuitable resource expenditures. To validate these inferences, a design optimization problem was presented requiring the inexpensive estimation of aerodynamic forces applied to a valve operating on a simulated piston-cylinder heat engine. The determination of these forces was to be found using parallel surrogate and exact approximation methods, thus evidencing the comparative
Form birefringent microstructures: modeling and design
NASA Astrophysics Data System (ADS)
Richter, I.; Sun, Pang Chen; Xu, Fang; Fainman, Yeshaiahu
1995-04-01
Diffraction characteristics of high-spatial-frequency gratings (HSF) are evaluated for application to polarization-selective computer generated holograms using two different approaches, second order effective-medium theory (EMT) and rigorous coupled-wave analysis (RCWA). The reflectivities and the phase differences for TE and TM polarized waves are investigated in terms of various input parameters, and results obtained with second order EMT and RCWA are compared. It is shown that while the reflection characteristics can be accurately modeled using the second order EMT, the phase difference created by form birefringence for TE and TM polarized waves requires the use of a more rigorous, RCWA approach. Design of HSF gratings in terms of their form birefringence and reflectivity properties is discussed in conjunction with polarization-selective computer generated holograms. A specific design optimization example furnishes a grating profile that provides a trade-off between largest form birefringence and lowest reflectivities.
Accuracy issues in modeling superplastic metal forming
Johnson, K.I.; Khaleel, M.A.; Lavender, C.A.; Smith, M.T.
1995-02-01
The utility of finite element modeling in optimizing superplastic metal forming is dependent on accurate representation of the material constitutive behavior and the frictional response of the sheet against the die surface. This paper presents work conducted to estimate the level of precision that is necessary in constitutive relations for finite element analysis to accurately predict the deformation history of actual SPF components. Previous work identified errors in SPF testing methods that use short tensile specimens with gauge length-to-width ratios of 2:1 or less. The analysis of the present paper was performed to estimate the error in predicted stress that results from using the short specimens. Stress correction factors were developed and an improved constitutive relation was implemented in the MARC finite element code to simulate the forming of a long, rectangular tray. The coefficient of friction in a Coulomb friction model was adjusted to reproduce the amount of material draw-in observed in the forming experiments. Comparisons between the finite element predictions and the forming experiments are presented.
Consolidation modelling for thermoplastic composites forming simulation
NASA Astrophysics Data System (ADS)
Xiong, H.; Rusanov, A.; Hamila, N.; Boisse, P.
2016-10-01
Pre-impregnated thermoplastic composites are widely used in the aerospace industry for their excellent mechanical properties, Thermoforming thermoplastic prepregs is a fast manufacturing process, the automotive industry has shown increasing interest in this manufacturing processes, in which the reconsolidation is an essential stage. The model of intimate contact is investigated as the consolidation model, compression experiments have been launched to identify the material parameters, several numerical tests show the influents of the temperature and pressure applied during processing. Finally, a new solid-shell prismatic element has been presented for the simulation of consolidation step in the thermoplastic composites forming process.
An Analytic Model of Close-Range Blast Fragment Loading
NASA Astrophysics Data System (ADS)
Rottenkolber, Ernst; Arnold, Werner
2006-07-01
The effects of blast-fragmentation warheads need to be carefully characterized in a variety of applications like passive and active vehicle protection or hard target defeat and TBM defense. With these applications in mind, we have developed a collection of tools called FI-BLAST (Fast Interface for Blast-Fragment Load Analysis of Structures). In the present paper we describe the essential part of these tools, namely the close range blast-fragment model. The meaning of "close range" is here defined as the standoff to a charge at which blast effects can inflict serious damage on massive structures. In order to quantify our model's range of validity, examples of measured and calculated momentum of bare and confined charges are given in the present paper. Short (L/D = 0.5) and long (L/D = 5) cylindrical charges are included as well as spherical charges. The presented examples demonstrate that the model gives reasonable results in the intended domains of application.
ERIC Educational Resources Information Center
Hayduk, Leslie
2014-01-01
Researchers using factor analysis tend to dismiss the significant ill fit of factor models by presuming that if their factor model is close-to-fitting, it is probably close to being properly causally specified. Close fit may indeed result from a model being close to properly causally specified, but close-fitting factor models can also be seriously…
Experiment close out of lysimeter testing of low-level radioactive waste forms
McConnell, J.W. Jr.; Rogers, R.D.; Jastrow, J.D.; Cline, S.R.; Sullivan, T.M.; Reed, P.
1997-12-31
The program is obtaining information on the performance of radioactive waste forms (WFs). These experiments were recently shut down and the contents of the lysimeters have been examined in accordance with a detailed waste form and soil sampling plan. Ion-exchange resins from a commercial nuclear power station were solidified into waste forms using portland cement and vinyl ester-styrene. These waste forms were tested to (a) obtain information on performance of waste forms in typical disposal environments, (b) compare field results with bench leach studies, (c) develop a low-level waste data base for use in performance assessment source term calculations, and (d) apply the DUST computer code to compare predicted cumulative release to actual field data. The program includes observed radionuclide releases from waste forms in field lysimeters at two test sites over 10 years of successful operation. The purpose of this paper is to present the results of the examination of waste forms and soils of the two lysimeter arrays after shut down. During this examination, the waste forms were characterized after removal from the lysimeters and the results compared to the findings of the original characterizations. Vertical soil cores were taken from the soil columns and analyzed with radiochemistry to define movement of radionuclides in the soils after release from the waste forms. A comparison is made of the DUST code predictions of releases using recently developed partition coefficients to actual radionuclide movement through the soil columns as determined from these core analyses. This paper discusses soil and waste form sampling in which vertical cores were removed from the lysimeter soil columns for laboratory characterization. Those samples will be analyzed for radionuclide movement from the waste forms and through the soil columns.
46 CFR 308.535 - Certificate to be attached to final closing report, Form MA-313-B.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 46 Shipping 8 2014-10-01 2014-10-01 false Certificate to be attached to final closing report, Form MA-313-B. 308.535 Section 308.535 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance Open Policy War Risk Cargo Insurance §...
Experiment close out of lysimeter field testing of low-level radioactive waste forms
McConnell, J.W. Jr.; Rogers, R.D.; Jastrow, J.D.
1998-03-01
The Field Lysimeter Investigations: Low-Level Waste Data Base Development Program is obtaining information on the performance of radioactive waste forms. These experiments were recently shut down and the contents of the lysimeters have been examined in accordance with a detailed waste form and soil sampling plan. Ion-exchange resins from a commercial nuclear power station were solidified into waste forms using portland cement and vinyl ester-styrene. These waste forms were tested to (a) obtain information on performance of waste forms in typical disposal environments, (b) compare field results with bench leach studies, (c) develop a low-level waste data base for use in performance assessment source term calculations, and (d) apply the DUST computer code to compare predicted cumulative release to actual field data. The program, funded by the Nuclear Regulatory Commission (NRC), includes observed radio nuclide releases from waste forms in field lysimeters at two test sites over 10 years of successful operation. The purpose of this paper is to present the results of the examination of waste forms and soils of the two lysimeter arrays after shut down. During this examination, the waste forms were characterized after removal from the lysimeters and the results compared to the findings of the original characterizations. Vertical soil cores were taken from the soil columns and analyzed with radiochemistry to define movement of radionuclides in the soils after release from the waste forms. A comparison is made of the DUST and BLT code predictions of releases and movement, using recently developed partition coefficients and leachate measurements, to actual radio nuclide movement through the soil columns as determined from these core analyses.
Porous Media Approach for Modeling Closed Cell Foam
NASA Technical Reports Server (NTRS)
Ghosn, Louis J.; Sullivan, Roy M.
2006-01-01
In order to minimize boil off of the liquid oxygen and liquid hydrogen and to prevent the formation of ice on its exterior surface, the Space Shuttle External Tank (ET) is insulated using various low-density, closed-cell polymeric foams. Improved analysis methods for these foam materials are needed to predict the foam structural response and to help identify the foam fracture behavior in order to help minimize foam shedding occurrences. This presentation describes a continuum based approach to modeling the foam thermo-mechanical behavior that accounts for the cellular nature of the material and explicitly addresses the effect of the internal cell gas pressure. A porous media approach is implemented in a finite element frame work to model the mechanical behavior of the closed cell foam. The ABAQUS general purpose finite element program is used to simulate the continuum behavior of the foam. The soil mechanics element is implemented to account for the cell internal pressure and its effect on the stress and strain fields. The pressure variation inside the closed cells is calculated using the ideal gas laws. The soil mechanics element is compatible with an orthotropic materials model to capture the different behavior between the rise and in-plane directions of the foam. The porous media approach is applied to model the foam thermal strain and calculate the foam effective coefficient of thermal expansion. The calculated foam coefficients of thermal expansion were able to simulate the measured thermal strain during heat up from cryogenic temperature to room temperature in vacuum. The porous media approach was applied to an insulated substrate with one inch foam and compared to a simple elastic solution without pore pressure. The porous media approach is also applied to model the foam mechanical behavior during subscale laboratory experiments. In this test, a foam layer sprayed on a metal substrate is subjected to a temperature variation while the metal substrate is
Form factors for Russian doll droplet models
NASA Astrophysics Data System (ADS)
Wilemski, G.; Obeidat, A.; Hrahsheh, F.
2013-05-01
Molecular dynamics (MD) simulations of nanodroplets containing water and nonane show them to be nonspherical and strongly phase separated. A simple, but realistic model for these "Russian doll" structures is a spherical nonane lens that partially wets a spherical water droplet. This document contains an analytical calculation of the particle form factor P(q) needed to analyze experimental measurements of small angle neutron and x-ray scattering from aerosols of particles with this type of structure. In addition, an exact formulation of the particle form factor is developed for cylindrically symmetric droplets with otherwise arbitrary scattering length density functions. This result will be useful to calculate P(q) directly from MD simulation results. We compare results using both formulations and find excellent agreement between them.
Model of wealth and goods dynamics in a closed market
NASA Astrophysics Data System (ADS)
Ausloos, Marcel; Peķalski, Andrzej
2007-01-01
A simple computer simulation model of a closed market on a fixed network with free flow of goods and money is introduced. The model contains only two variables: the amount of goods and money beside the size of the system. An initially flat distribution of both variables is presupposed. We show that under completely random rules, i.e. through the choice of interacting agent pairs on the network and of the exchange rules that the market stabilizes in time and shows diversification of money and goods. We also indicate that the difference between poor and rich agents increases for small markets, as well as for systems in which money is steadily deduced from the market through taxation. It is also found that the price of goods decreases when taxes are introduced, likely due to the less availability of money.
17 CFR Appendix A to Part 160 - Model Privacy Form
Code of Federal Regulations, 2010 CFR
2010-04-01
... notice, to meet the content requirements of the privacy notice and opt-out notice set forth in §§ 160.6 and 160.7 of this part. (b) The model form is a standardized form, including page layout, content... the model form, as appropriate. 2. The Contents of the Model Privacy Form The model form consists...
Theater and ALife Art: Modeling Open and Closed Systems.
Norman, Sally Jane
2015-01-01
The live art of theater remains curiously missing from ALife art history, despite the fact that its very existence is poised on the cusp of the living and the artificial, and on the modeling of life as artefact-what can be called the containment-versus-continuity dilemma. How far one seeks to affirm autonomy of the creative artwork or, in contrast, how far one seeks to affirm its continuity with its supposed real-life contexts is a question that has forever haunted theater, and that has naturally come to haunt ALife and ALife arts. Investigation of the boundary separating observers from modeled systems is as core to research into the live art of theater as to ALife research. This brief article seeks to open up discussion on links between ALife, ALife art, and the live art of theater, through key thematic threads that traverse these domains: their modeling of universes, the open or closed nature of the resultant modeled systems, and their implications with respect to observers, definitions, and instantiations of life regarding non-life or death as well as attributions of liveness to emergent synthetic biology and metamaterials.
Modeling embryo transfer into a closed uterine cavity.
Yaniv, Sarit; Jaffa, Ariel J; Elad, David
2012-11-01
Embryo transfer (ET) is the last manual intervention after extracorporeal fertilization. After the ET procedure is completed, the embryos are conveyed in the uterus for another two to four days due to spontaneous uterine peristalsis until the window time for implantation. The role of intrauterine fluid flow patterns in transporting the embryos to their implantation site during and after ET was simulated by injection of a liquid bolus into a two-dimensional liquid-filled channel with a closed fundal end via a liquid-filled catheter inserted in the channel. Numerical experiments revealed that the intrauterine fluid field and the embryos transport pattern were strongly affected by the closed fundal end. The embryos re-circulated in small loops around the vicinity where they were deposited from the catheter. The transport pattern was controlled by the uterine peristalsis factors, such as amplitude and frequency of the uterine walls motility, as well as the synchronization between the onset of catheter discharge and uterine peristalsis. The outcome of ET was also dependent on operating parameters such as placement of the catheter tip within the uterine cavity and the delivery speed of the catheter load. In conclusion, this modeling study highlighted important parameters that should be considered during ET procedures in order to increase the potential for pregnancy success.
A statistical study of close binary systems: testing evolutionary models
NASA Astrophysics Data System (ADS)
Leão, I. C.; de Medeiros, J. R.
2003-08-01
The evolution of stars in close binary systems differs from that of their single counterparts essentially in two main aspects: (i) the rotation of each component is directly affected by tidal interactions, which determine the evolution of orbital parameters and rotations of the system, and (ii) the evolutionary tracks of the stars run in considerably different ways when the mass transfer process begins, which occurs when the primary evolves sufficiently and reaches its Roche limit. The present work brings a confrontation between observational data, including orbital parameters, rotation and age, and theoretical predictions obtained from detailed models of binary systems evolution. For this study we have selected a sample of binary systems, mostly with a F-, G- or K-type primary component, with orbital parameters and rotational velocity available in the literature. For the theoretical predictions we have used stellar evolutionary models by Claret 1998 (A&AS 131, 395) and Schaller et al. 1992 (A&AS 96, 269) combined with models of binary orbital parameters evolution by Zahn 1977 (A&A 57, 383) and Zahn 1978 (A&A 67, 162). The preliminary results point for a good agreement between the observed orbital eccentricity, orbital and rotational periods and the predicted values as a function of stellar age. In addition, we present an analysis of the relationship between Vrot/Vk (where Vrot and Vk are, respectively, the rotational and keplerian velocities) and the stellar fractional radius, to rediscuss the synchronization process between rotation and orbital motions.
12 CFR Appendix B to Part 1002 - Model Application Forms
Code of Federal Regulations, 2013 CFR
2013-01-01
... 12 Banks and Banking 8 2013-01-01 2013-01-01 false Model Application Forms B Appendix B to Part... B) Pt. 1002, App. B Appendix B to Part 1002—Model Application Forms 1. This appendix contains five... form. 3. If a creditor uses an appropriate appendix B model form, or modifies a form in accordance...
12 CFR Appendix B to Part 1002 - Model Application Forms
Code of Federal Regulations, 2012 CFR
2012-01-01
... 12 Banks and Banking 8 2012-01-01 2012-01-01 false Model Application Forms B Appendix B to Part... B) Pt. 1002, App. B Appendix B to Part 1002—Model Application Forms 1. This Appendix contains five... form. 3. If a creditor uses an appropriate Appendix B model form, or modifies a form in accordance...
12 CFR Appendix B to Part 1002 - Model Application Forms
Code of Federal Regulations, 2014 CFR
2014-01-01
... 12 Banks and Banking 8 2014-01-01 2014-01-01 false Model Application Forms B Appendix B to Part... B) Pt. 1002, App. B Appendix B to Part 1002—Model Application Forms 1. This appendix contains five... form. 3. If a creditor uses an appropriate appendix B model form, or modifies a form in accordance...
12 CFR Appendix A to Part 716 - Model Privacy Form
Code of Federal Regulations, 2010 CFR
2010-01-01
... institution, including a group of financial institutions that use a common privacy notice, to meet the content... model form is a standardized form, including page layout, content, format, style, pagination, and... form, as appropriate. 2. The Contents of the Model Privacy Form The model form consists of two...
12 CFR Appendix A to Part 573 - Model Privacy Form
Code of Federal Regulations, 2010 CFR
2010-01-01
... institution, including a group of financial institutions that use a common privacy notice, to meet the content... model form is a standardized form, including page layout, content, format, style, pagination, and... form, as appropriate. 2. The Contents of the Model Privacy Form The model form consists of two...
NASA Astrophysics Data System (ADS)
Matone, Marco
2016-11-01
Recently it has been introduced an algorithm for the Baker-Campbell-Hausdorff (BCH) formula, which extends the Van-Brunt and Visser recent results, leading to new closed forms of BCH formula. More recently, it has been shown that there are 13 types of such commutator algebras. We show, by providing the explicit solutions, that these include the generators of the semisimple complex Lie algebras. More precisely, for any pair, X, Y of the Cartan-Weyl basis, we find W, linear combination of X, Y, such that exp (X) exp (Y)=exp (W). The derivation of such closed forms follows, in part, by using the above mentioned recent results. The complete derivation is provided by considering the structure of the root system. Furthermore, if X, Y, and Z are three generators of the Cartan-Weyl basis, we find, for a wide class of cases, W, a linear combination of X, Y and Z, such that exp (X) exp (Y) exp (Z)=exp (W). It turns out that the relevant commutator algebras are type 1c-i, type 4 and type 5. A key result concerns an iterative application of the algorithm leading to relevant extensions of the cases admitting closed forms of the BCH formula. Here we provide the main steps of such an iteration that will be developed in a forthcoming paper.
Mobile close combat tactical trainer location and routing model
Djang, P.; Scott, M.
1994-12-31
In the short term future, the Army will purchase 21 Mobile Close Combat Tactical Trainers (MCCTTs) for the Reserve Component. The Army plans to buy 11 Armor and 10 Infantry versions of these trainers. The trainers are high fidelity simulators that teach tactical operations at the company and platoon level. The simulators are mounted on 3 tractor-trailers and are capable of traveling to the cities, towns and villages (known as home stations) where the Reserve Component platoons reside. The TRADOC System Manager - Combined Arms Tactical Trainer requested that TRAC-WSMR conduct a stationing analysis to determine where these devices should be located. We have created location and routing models for both Armor and Infantry MCCTTs. We developed a p-median model to determine the locations that minimize the distance between the MCCTTs and a number of home stations. Once we know where to locate the MCCTTs, we developed transportation, set covering and traveling salesperson models to decide the routing strategy that minimizes the distance the MCCTTs must travel, thereby prolonging their life. Our models insure that all platoons receive a minimum of three MCCTT training sessions per year and that the units do not have to travel more than 60 miles away from their home. If the Army uses the same routing strategy for the MCCTTs as they have done for a predecessor system, then our efforts have estimated annual savings of 700, 000 or 10 Million over the system life. Finally, given the current training requirement, our work demonstrates that the Army`s procurement strategy needs to be adjusted; we show that the Army needs to buy fewer Infantry MCCTTs than planned; we show that if the excess is converted to Armor MCCTTs, then a less expensive overall solution can be computed.
A Drosophila model of closed head traumatic brain injury.
Katzenberger, Rebeccah J; Loewen, Carin A; Wassarman, Douglas R; Petersen, Andrew J; Ganetzky, Barry; Wassarman, David A
2013-10-29
Traumatic brain injury (TBI) is a substantial health issue worldwide, yet the mechanisms responsible for its complex spectrum of pathologies remains largely unknown. To investigate the mechanisms underlying TBI pathologies, we developed a model of TBI in Drosophila melanogaster. The model allows us to take advantage of the wealth of experimental tools available in flies. Closed head TBI was inflicted with a mechanical device that subjects flies to rapid acceleration and deceleration. Similar to humans with TBI, flies with TBI exhibited temporary incapacitation, ataxia, activation of the innate immune response, neurodegeneration, and death. Our data indicate that TBI results in death shortly after a primary injury only if the injury exceeds a certain threshold and that age and genetic background, but not sex, substantially affect this threshold. Furthermore, this threshold also appears to be dependent on the same cellular and molecular mechanisms that control normal longevity. This study demonstrates the potential of flies for providing key insights into human TBI that may ultimately provide unique opportunities for therapeutic intervention.
12 CFR 332.2 - Model privacy form and examples.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 12 Banks and Banking 4 2010-01-01 2010-01-01 false Model privacy form and examples. 332.2 Section 332.2 Banks and Banking FEDERAL DEPOSIT INSURANCE CORPORATION REGULATIONS AND STATEMENTS OF GENERAL POLICY PRIVACY OF CONSUMER FINANCIAL INFORMATION § 332.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form...
17 CFR 160.2 - Model privacy form and examples.
Code of Federal Regulations, 2010 CFR
2010-04-01
... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Model privacy form and examples. 160.2 Section 160.2 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION PRIVACY OF CONSUMER FINANCIAL INFORMATION § 160.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in appendix A...
16 CFR 313.2 - Model privacy form and examples.
Code of Federal Regulations, 2014 CFR
2014-01-01
... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Model privacy form and examples. 313.2... PRIVACY OF CONSUMER FINANCIAL INFORMATION § 313.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in appendix A of this part, consistent with the instructions in...
17 CFR 160.2 - Model privacy form and examples.
Code of Federal Regulations, 2012 CFR
2012-04-01
... 17 Commodity and Securities Exchanges 1 2012-04-01 2012-04-01 false Model privacy form and... PRIVACY OF CONSUMER FINANCIAL INFORMATION UNDER TITLE V OF THE GRAMM-LEACH-BLILEY ACT § 160.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in appendix A of...
17 CFR 160.2 - Model privacy form and examples.
Code of Federal Regulations, 2011 CFR
2011-04-01
... 17 Commodity and Securities Exchanges 1 2011-04-01 2011-04-01 false Model privacy form and... PRIVACY OF CONSUMER FINANCIAL INFORMATION § 160.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in appendix A of this part, consistent with the instructions in...
12 CFR 716.2 - Model privacy form and examples.
Code of Federal Regulations, 2012 CFR
2012-01-01
... 12 Banks and Banking 7 2012-01-01 2012-01-01 false Model privacy form and examples. 716.2 Section... PRIVACY OF CONSUMER FINANCIAL INFORMATION § 716.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in Appendix A of this part, consistent with the instructions in...
12 CFR 716.2 - Model privacy form and examples.
Code of Federal Regulations, 2011 CFR
2011-01-01
... 12 Banks and Banking 6 2011-01-01 2011-01-01 false Model privacy form and examples. 716.2 Section... PRIVACY OF CONSUMER FINANCIAL INFORMATION § 716.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in appendixA of this part, consistent with the instructions in...
16 CFR 313.2 - Model privacy form and examples.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Model privacy form and examples. 313.2... PRIVACY OF CONSUMER FINANCIAL INFORMATION § 313.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in appendix A of this part, consistent with the instructions in...
12 CFR 332.2 - Model privacy form and examples.
Code of Federal Regulations, 2011 CFR
2011-01-01
... 12 Banks and Banking 4 2011-01-01 2011-01-01 false Model privacy form and examples. 332.2 Section... POLICY PRIVACY OF CONSUMER FINANCIAL INFORMATION § 332.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in Appendix A of this part, consistent with the...
12 CFR 332.2 - Model privacy form and examples.
Code of Federal Regulations, 2014 CFR
2014-01-01
... 12 Banks and Banking 5 2014-01-01 2014-01-01 false Model privacy form and examples. 332.2 Section... POLICY PRIVACY OF CONSUMER FINANCIAL INFORMATION § 332.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in appendix A of this part, consistent with the...
12 CFR 216.2 - Model privacy form and examples.
Code of Federal Regulations, 2014 CFR
2014-01-01
... 12 Banks and Banking 2 2014-01-01 2014-01-01 false Model privacy form and examples. 216.2 Section... PRIVACY OF CONSUMER FINANCIAL INFORMATION (REGULATION P) § 216.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in appendix A of this part, consistent with...
12 CFR 216.2 - Model privacy form and examples.
Code of Federal Regulations, 2011 CFR
2011-01-01
... 12 Banks and Banking 2 2011-01-01 2011-01-01 false Model privacy form and examples. 216.2 Section... PRIVACY OF CONSUMER FINANCIAL INFORMATION (REGULATION P) § 216.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in appendix A of this part, consistent with...
17 CFR 160.2 - Model privacy form and examples.
Code of Federal Regulations, 2013 CFR
2013-04-01
... 17 Commodity and Securities Exchanges 1 2013-04-01 2013-04-01 false Model privacy form and... PRIVACY OF CONSUMER FINANCIAL INFORMATION UNDER TITLE V OF THE GRAMM-LEACH-BLILEY ACT § 160.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in appendix A of...
16 CFR 313.2 - Model privacy form and examples.
Code of Federal Regulations, 2013 CFR
2013-01-01
... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Model privacy form and examples. 313.2... PRIVACY OF CONSUMER FINANCIAL INFORMATION § 313.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in appendix A of this part, consistent with the instructions in...
12 CFR 716.2 - Model privacy form and examples.
Code of Federal Regulations, 2013 CFR
2013-01-01
... 12 Banks and Banking 7 2013-01-01 2013-01-01 false Model privacy form and examples. 716.2 Section... PRIVACY OF CONSUMER FINANCIAL INFORMATION § 716.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in Appendix A of this part, consistent with the instructions in...
12 CFR 216.2 - Model privacy form and examples.
Code of Federal Regulations, 2012 CFR
2012-01-01
... 12 Banks and Banking 2 2012-01-01 2012-01-01 false Model privacy form and examples. 216.2 Section... PRIVACY OF CONSUMER FINANCIAL INFORMATION (REGULATION P) § 216.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in appendix A of this part, consistent with...
12 CFR 332.2 - Model privacy form and examples.
Code of Federal Regulations, 2013 CFR
2013-01-01
... 12 Banks and Banking 5 2013-01-01 2013-01-01 false Model privacy form and examples. 332.2 Section... POLICY PRIVACY OF CONSUMER FINANCIAL INFORMATION § 332.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in appendix A of this part, consistent with the...
17 CFR 160.2 - Model privacy form and examples.
Code of Federal Regulations, 2014 CFR
2014-04-01
... 17 Commodity and Securities Exchanges 2 2014-04-01 2014-04-01 false Model privacy form and... (CONTINUED) PRIVACY OF CONSUMER FINANCIAL INFORMATION UNDER TITLE V OF THE GRAMM-LEACH-BLILEY ACT § 160.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in appendix A...
12 CFR 716.2 - Model privacy form and examples.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Model privacy form and examples. 716.2 Section... PRIVACY OF CONSUMER FINANCIAL INFORMATION § 716.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in Appendix A of this part, consistent with the instructions in...
16 CFR 313.2 - Model privacy form and examples.
Code of Federal Regulations, 2012 CFR
2012-01-01
... 16 Commercial Practices 1 2012-01-01 2012-01-01 false Model privacy form and examples. 313.2... PRIVACY OF CONSUMER FINANCIAL INFORMATION § 313.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in appendix A of this part, consistent with the instructions in...
12 CFR 332.2 - Model privacy form and examples.
Code of Federal Regulations, 2012 CFR
2012-01-01
... 12 Banks and Banking 5 2012-01-01 2012-01-01 false Model privacy form and examples. 332.2 Section... POLICY PRIVACY OF CONSUMER FINANCIAL INFORMATION § 332.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in appendix A of this part, consistent with the...
16 CFR 313.2 - Model privacy form and examples.
Code of Federal Regulations, 2011 CFR
2011-01-01
... 16 Commercial Practices 1 2011-01-01 2011-01-01 false Model privacy form and examples. 313.2... PRIVACY OF CONSUMER FINANCIAL INFORMATION § 313.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in appendix A of this part, consistent with the instructions in...
12 CFR 216.2 - Model privacy form and examples.
Code of Federal Regulations, 2013 CFR
2013-01-01
... 12 Banks and Banking 2 2013-01-01 2013-01-01 false Model privacy form and examples. 216.2 Section... PRIVACY OF CONSUMER FINANCIAL INFORMATION (REGULATION P) § 216.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in appendix A of this part, consistent with...
Closed-Head TBI Model of Multiple Morbidity.
Thompson, Floyd J; Hou, Jiamei; Bose, Prodip K
2016-01-01
Successful therapy for TBI disabilities awaits refinement in the understanding of TBI neurobiology, quantitative measurement of treatment-induced incremental changes in recovery trajectories, and effective translation to human TBI using quantitative methods and protocols that were effective to monitor recovery in preclinical models. Details of the specific neurobiology that underlies these injuries and effective quantitation of treatment-induced changes are beginning to emerge utilizing a variety of preclinical and clinical models (for reviews see (Morales et al., Neuroscience 136:971-989, 2005; Fujimoto et al., Neurosci Biobehav Rev 28:365-378, 2004; Cernak, NeuroRx 2:410-422, 2005; Smith et al., J Neurotrauma 22:1485-1502, 2005; Bose et al., J Neurotrauma 30:1177-1191, 2013; Xiong et al., Nat Rev Neurosci 14:128-142, 2013; Xiong et al., Expert Opin Emerg Drugs 14:67-84, 2009; Johnson et al., Handb Clin Neurol 127:115-128, 2015; Bose et al., Brain neurotrauma: molecular, neuropsychological, and rehabilitation aspects, CRC Press/Taylor & Francis, Boca Raton, 2015)). Preclinical models of TBI, essential for the efficient study of TBI neurobiology, benefit from the setting of controlled injury and optimal opportunities for biometric quantitation of injury and treatment-induced changes in the trajectories of disability. Several preclinical models are currently used, and each offer opportunities for study of different aspects of TBI primary and secondary injuries (for review see (Morales et al., Neuroscience 136:971-989, 2005; Xiong et al., Nat Rev Neurosci 14:128-142, 2013; Xiong et al., Expert Opin Emerg Drugs 14:67-84, 2009; Johnson et al., Handb Clin Neurol 127:115-128, 2015; Dixon et al., J Neurotrauma 5:91-104, 1988)). The closed-head, impact-acceleration model of TBI designed by Marmarou et al., 1994 (J Neurosurg 80:291-300, 1994), when used to produce mild to moderate TBI, produces diffuse axonal injuries without significant additional focal injuries of the
Closed-form solution for loop transfer recovery via reduced-order observers
NASA Technical Reports Server (NTRS)
Bacon, Barton J.
1989-01-01
A well-known property of the reduced-order observer is exploited to obtain the controller solution of the loop transfer recovery problem. In that problem, the controller is sought that generates some desired loop shape at the plant's input or output channels. Past approaches to this problem have typically yielded controllers generating loop shapes that only converge pointwise to the desired loop shape. In the proposed approach, however, the solution (at the input) is obtained directly when the plant's first Markov parameter is full rank. In the more general case when the plant's first Markov parameter is not full rank, the solution is obtained in an analogous manner by appending a special set of input and output signals to the original set. A dual form of the reduced-order observer is shown to yield the LTR solution at the output channel.
Fiori, Simone
2003-12-01
In recent work, we introduced nonlinear adaptive activation function (FAN) artificial neuron models, which learn their activation functions in an unsupervised way by information-theoretic adapting rules. We also applied networks of these neurons to some blind signal processing problems, such as independent component analysis and blind deconvolution. The aim of this letter is to study some fundamental aspects of FAN units' learning by investigating the properties of the associated learning differential equation systems.
Li, Xin; Sandh, Gustaf; Nenninger, Anja; Muro-Pastor, Alicia M; Stensjö, Karin
2015-03-01
In cyanobacteria, DNA-binding proteins from starved cells (Dps) play an important role in the cellular response to oxidative and nutritional stresses. In this study, we have characterized the cell-type specificity and the promoter regions of two orthologous dps genes, Npun_R5799 in Nostoc punctiforme and alr3808 in Anabaena sp. PCC 7120. A transcriptional start site (TSS), identical in location to the previously identified proximal TSS of alr3808, was identified for Npun_R5799 under both combined nitrogen supplemented and N2-fixing growth conditions. However, only alr3808 was also transcribed from a second distal TSS. Sequence homologies suggest that the promoter region containing the distal TSS is not conserved upstream of orthologous genes among heterocyst-forming cyanobacteria. The analysis of promoter GFP-reporter strains showed a different role in governing cell-type specificity between the proximal and distal promoter of alr3808. We here confirmed the heterocyst specificity of the distal promoter of alr3808 and described a very early induction of its expression during proheterocyst differentiation. In contrast, the complete promoters of both genes were active in all cells. Even though Npun_R5799 and alr3808 are orthologs, the regulation of their respective expression differs, indicating distinctions in the function of these cyanobacterial Dps proteins depending on the strain and cell type.
A new approach towards image based virtual 3D city modeling by using close range photogrammetry
NASA Astrophysics Data System (ADS)
Singh, S. P.; Jain, K.; Mandla, V. R.
2014-05-01
3D city model is a digital representation of the Earth's surface and it's related objects such as building, tree, vegetation, and some manmade feature belonging to urban area. The demand of 3D city modeling is increasing day to day for various engineering and non-engineering applications. Generally three main image based approaches are using for virtual 3D city models generation. In first approach, researchers used Sketch based modeling, second method is Procedural grammar based modeling and third approach is Close range photogrammetry based modeling. Literature study shows that till date, there is no complete solution available to create complete 3D city model by using images. These image based methods also have limitations This paper gives a new approach towards image based virtual 3D city modeling by using close range photogrammetry. This approach is divided into three sections. First, data acquisition process, second is 3D data processing, and third is data combination process. In data acquisition process, a multi-camera setup developed and used for video recording of an area. Image frames created from video data. Minimum required and suitable video image frame selected for 3D processing. In second section, based on close range photogrammetric principles and computer vision techniques, 3D model of area created. In third section, this 3D model exported to adding and merging of other pieces of large area. Scaling and alignment of 3D model was done. After applying the texturing and rendering on this model, a final photo-realistic textured 3D model created. This 3D model transferred into walk-through model or in movie form. Most of the processing steps are automatic. So this method is cost effective and less laborious. Accuracy of this model is good. For this research work, study area is the campus of department of civil engineering, Indian Institute of Technology, Roorkee. This campus acts as a prototype for city. Aerial photography is restricted in many country
Closed-form irreducible differential formulations of the Wilson renormalization group
NASA Astrophysics Data System (ADS)
Vvedensky, D. D.; Chang, T. S.; Nicoll, J. F.
1983-06-01
We present a detailed derivation of the one-particle-irreducible (1PI) differential renormalization-group generators originally developed by Nicoll and Chang and by Chang, Nicoll, and Young. We illustrate the machinery of the irreducible formulation by calculating to order ɛ2 the characteristic time exponent z for the time-dependent Ginsburg-Landau model in the cases of conserved and nonconserved order parameter. We then calculate both z and η to order ɛ2 by applying to the 1PI generator an extension of the operator expansion technique developed by Wegner for the Wilson smooth-cutoff renormalization-group generator.
Closed-form equation of state for Lennard-Jones molecules based on perturbation theory
Bokis, C.P.; Donohue, M.D.
1995-08-17
A comparison of virial theory and perturbation theory for spherical molecules is presented. A new equation of state is derived. This new model has the exact second virial coefficient behavior, converges to the correct mean-field behavior at high densities, and successfully interpolates between these two limits. This new equation of state is applied to molecules that interact via the Lennard-Jones potential. Comparison is made with computer simulation results for the configurational energy, the compressibility factor, and the second virial coefficient of Lennard-Jones molecules. 25 refs., 7 figs.
The hydrodynamic model testing for closed loop DP assisted mooring
Aalbers, A.B.; Merchant, A.A.
1996-12-31
Far East Levingston Shipbuilding (FELS) is presently completing the construction of the Smedvig Production Unit SPU 380, which will be operated as FPSO for Esso Balder Field Offshore Norway. In good cooperation with FELS and ND and A Inc. of Houston an extensive model test program was carried out for approval and optimization of the DP assisted mooring system. The main aspects were: investigate the performance of the mooring in two water depths, i.e. 250 m and 70 m; optimization of DP control for the three azimuthing thrusters; measurement of motions and wave induced loads at e.g., the bilge keels, keel and deckhouse front; and determination of limit sea state for turning the vessel around against the weather. The tests were carried out in the Wave and Current Basin of MARIN, using a closed loop DP control system to steer the thrusters. The paper presents the findings with respect to the effect of DP control strategy on mooring loads and presents selected results of wave induced loads on bilge keels and deck house.
IMC-PID design based on model matching approach and closed-loop shaping.
Jin, Qi B; Liu, Q
2014-03-01
Motivated by the limitations of the conventional internal model control (IMC), this communication addresses the design of IMC-based PID in terms of the robust performance of the control system. The IMC controller form is obtained by solving an H-infinity problem based on the model matching approach, and the parameters are determined by closed-loop shaping. The shaping of the closed-loop transfer function is considered both for the set-point tracking and for the load disturbance rejection. The design procedure is formulated as a multi-objective optimization problem which is solved by a specific optimization algorithm. A nice feature of this design method is that it permits a clear tradeoff between robustness and performance. Simulation examples show that the proposed method is effective and has a wide applicability.
Modeling biominerals formed by apatites and DNA.
Revilla-López, Guillermo; Casanovas, Jordi; Bertran, Oscar; Turon, Pau; Puiggalí, Jordi; Alemán, Carlos
2013-12-01
Different aspects of biominerals formed by apatite and DNA have been investigated using computer modeling tools. Firstly, the structure and stability of biominerals in which DNA molecules are embedded into hydroxyapatite and fluoroapatite nanopores have been examined by combining different molecular mechanics methods. After this, the early processes in the nucleation of hydroxyapatite at a DNA template have been investigated using molecular dynamics simulations. Results indicate that duplexes of DNA adopting a B double helix can be encapsulated inside nanopores of hydroxyapatite without undergoing significant distortions in the inter-strand hydrogen bonds and the intra-strand stacking. This ability of hydroxyapatite is practically independent of the DNA sequence, which has been attributed to the stabilizing role of the interactions between the calcium atoms of the mineral and the phosphate groups of the biomolecule. In contrast, the fluorine atoms of fluoroapatite induce pronounced structural distortions in the double helix when embedded in a pore of the same dimensions, resulting in the loss of its most relevant characteristics. On the other hand, molecular dynamics simulations have allowed us to observe the formation of calcium phosphate clusters at the surface of the B-DNA template. Electrostatic interactions between the phosphate groups of DNA and Ca(2+) have been found to essential for the formation of stable ion complexes, which were the starting point of calcium phosphate clusters by incorporating PO3(4) from the solution.
A novel form of {open_quotes}Tyrosinase-positive{close_quotes} oculocutaneous albinism
Fukai, K.; Lee, S.T.; Bundey, S.; Spritz, R.A. |
1994-09-01
Tyrosinase-positive oculocutaneous albinism (ty-pos OCA) is an autosomal recessive disorder in which the biosynthesis of melanin pigment is greatly reduced in the skin, hair, and eyes. We have shown that typical ty-pos OCA (OCA2) results from mutations of the P gene in chromosome segment 15q11-q13. We have also shown that some patients diagnosed with ty-pos OCA actually have mild forms of type I OCA (OCAI), resulting from mutations at the tyrosinase (TYR) gene at 11q14-q21. However, in about one-third of patients with ty-pos OCA we have failed to identify abnormalities of either the P or TYR genes, suggesting the possible existence of a third ty-pos OCA locus. To test this hypothesis, we investigated a large, complex, inbred Pakistani kindred. Affected individuals exhibit slight skin pigmentation with no tanning, hair that is silver at birth and darkens somewhat over time, brown irides, and reduced visual acuity with nystagmus. SSCP/heteroduplex screening and complete DNA sequence analysis of TYR gene in the proband identified no abnormalities, and analysis of a CA repeat in the TYR gene promoter showed no linkage of ty-pos OCA to this marker in this kindred. SSCP/ heteroduplex screening of the P gene also detected no abnormalities, and the (inbred) proband was heterozygous for numerous intragenic polymorphisms. These data thus exclude TYP and P. We next carried out genetic linkage analyses and homozygisty mapping using various SSLP repeats at the locations of the human homologues of the mouse brown (TYRP, 9p23), slaty (13q32), and silver (12pter-q21) genes, all of which are associated with generalized hypopigmentation in mutant animals. However, we found no evidence of linkage of any of these markers. We are currently carrying out similar analyses using markers near the putative locations of the human homologues of several other mouse hypopigmentation genes in an effort to map this novel human ty-pos OCA locus.
12 CFR Appendix B to Part 202 - Model Application Forms
Code of Federal Regulations, 2012 CFR
2012-01-01
... 12 Banks and Banking 2 2012-01-01 2012-01-01 false Model Application Forms B Appendix B to Part... CREDIT OPPORTUNITY ACT (REGULATION B) Pt. 202, App. B Appendix B to Part 202—Model Application Forms 1... appear on the creditor's form. 3. If a creditor uses an appropriate Appendix B model form, or modifies...
12 CFR Appendix B to Part 202 - Model Application Forms
Code of Federal Regulations, 2013 CFR
2013-01-01
... 12 Banks and Banking 2 2013-01-01 2013-01-01 false Model Application Forms B Appendix B to Part... CREDIT OPPORTUNITY ACT (REGULATION B) Pt. 202, App. B Appendix B to Part 202—Model Application Forms 1... appear on the creditor's form. 3. If a creditor uses an appropriate appendix B model form, or modifies...
12 CFR Appendix B to Part 202 - Model Application Forms
Code of Federal Regulations, 2011 CFR
2011-01-01
... 12 Banks and Banking 2 2011-01-01 2011-01-01 false Model Application Forms B Appendix B to Part... CREDIT OPPORTUNITY ACT (REGULATION B) Pt. 202, App. B Appendix B to Part 202—Model Application Forms 1... appear on the creditor's form. 3. If a creditor uses an appropriate Appendix B model form, or modifies...
12 CFR Appendix B to Part 202 - Model Application Forms
Code of Federal Regulations, 2014 CFR
2014-01-01
... 12 Banks and Banking 2 2014-01-01 2014-01-01 false Model Application Forms B Appendix B to Part... CREDIT OPPORTUNITY ACT (REGULATION B) Pt. 202, App. B Appendix B to Part 202—Model Application Forms 1... appear on the creditor's form. 3. If a creditor uses an appropriate Appendix B model form, or modifies...
FORMING CLOSE-IN EARTH-LIKE PLANETS VIA A COLLISION-MERGER MECHANISM IN LATE-STAGE PLANET FORMATION
Ji Jianghui; Jin Sheng; Tinney, C. G. E-mail: qingxiaojin@gmail.com
2011-01-20
The large number of exoplanets found to orbit their host stars in very close orbits have significantly advanced our understanding of the planetary formation process. It is now widely accepted that such short-period planets cannot have formed in situ, but rather must have migrated to their current orbits from a formation location much farther from their host star. In the late stages of planetary formation, once the gas in the protoplanetary disk has dissipated and migration has halted, gas giants orbiting in the inner disk regions will excite planetesimals and planetary embryos, resulting in an increased rate of orbital crossings and large impacts. We present the results of dynamical simulations for planetesimal evolution in this later stage of planet formation. We find that a mechanism is revealed by which the collision-merger of planetary embryos can kick terrestrial planets directly into orbits extremely close to their parent stars.
NASA Technical Reports Server (NTRS)
Jamison, J. W.
1994-01-01
CFORM was developed by the Kennedy Space Center Robotics Lab to assist in linear control system design and analysis using closed form and transient response mechanisms. The program computes the closed form solution and transient response of a linear (constant coefficient) differential equation. CFORM allows a choice of three input functions: the Unit Step (a unit change in displacement); the Ramp function (step velocity); and the Parabolic function (step acceleration). It is only accurate in cases where the differential equation has distinct roots, and does not handle the case for roots at the origin (s=0). Initial conditions must be zero. Differential equations may be input to CFORM in two forms - polynomial and product of factors. In some linear control analyses, it may be more appropriate to use a related program, Linear Control System Design and Analysis (KSC-11376), which uses root locus and frequency response methods. CFORM was written in VAX FORTRAN for a VAX 11/780 under VAX VMS 4.7. It has a central memory requirement of 30K. CFORM was developed in 1987.
Kinesthetic and visual image in modeling closed motor skills: the example of the tennis serve.
Féry, Y A; Morizot, P
2000-06-01
It was assumed that kinesthetic modeling has more beneficial effects on learning the tennis serve than visual modeling because the spatial anchor points used to reach targets within the vicinity of the body are mainly defined with respect to the body. Also, we predicted that the efficiency of modeling is also affected by the way the representations are activated mentally. Thirty two participants were assigned to kinesthetic or visual modeling with or without mental practice. Analyses showed the primacy of kinesthetic representation over visual representation in terms of speed scores and form performances but only if the learner had the opportunity to rehearse the model mentally. The results support the contention that the motor system can program closed skills more easily when one can represent efficiently the kinesthetic image of its later execution.
Cystic Fibrosis Transmembrane Conductance Regulator (CFTR): CLOSED AND OPEN STATE CHANNEL MODELS.
Corradi, Valentina; Vergani, Paola; Tieleman, D Peter
2015-09-18
The cystic fibrosis transmembrane conductance regulator (CFTR) is a member of the ATP-binding cassette (ABC) transporter superfamily. CFTR controls the flow of anions through the apical membrane of epithelia. Dysfunctional CFTR causes the common lethal genetic disease cystic fibrosis. Transitions between open and closed states of CFTR are regulated by ATP binding and hydrolysis on the cytosolic nucleotide binding domains, which are coupled with the transmembrane (TM) domains forming the pathway for anion permeation. Lack of structural data hampers a global understanding of CFTR and thus the development of "rational" approaches directly targeting defective CFTR. In this work, we explored possible conformational states of the CFTR gating cycle by means of homology modeling. As templates, we used structures of homologous ABC transporters, namely TM(287-288), ABC-B10, McjD, and Sav1866. In the light of published experimental results, structural analysis of the transmembrane cavity suggests that the TM(287-288)-based CFTR model could correspond to a commonly occupied closed state, whereas the McjD-based model could represent an open state. The models capture the important role played by Phe-337 as a filter/gating residue and provide structural information on the conformational transition from closed to open channel.
Noncommutative-geometry model for closed bosonic strings
NASA Technical Reports Server (NTRS)
Sen, Siddhartha; Holman, R.
1987-01-01
It is shown how Witten's (1986) noncommutative geometry may be extended to describe the closed bosonic string. For closed strings, an explicit representation is provided of the integral operator needed to construct an action and of an associative product on string fields. The proper choice of the action of the integral operator and the associative product in order to give rise to a reasonable theory is explained, and the consequences of such a choice are discussed. It is shown that the ghost numbers of the operator and associative product can be chosen arbitrarily for both open and closed strings, and that this construct can be used as an action for interacting closed bosonic strings.
Ali, Farhad; Khan, Ilyas; Shafie, Sharidan
2014-01-01
Closed form solutions for unsteady free convection flows of a second grade fluid near an isothermal vertical plate oscillating in its plane using the Laplace transform technique are established. Expressions for velocity and temperature are obtained and displayed graphically for different values of Prandtl number Pr, thermal Grashof number Gr, viscoelastic parameter α, phase angle ωτ and time τ. Numerical values of skin friction τ 0 and Nusselt number Nu are shown in tables. Some well-known solutions in literature are reduced as the limiting cases of the present solutions.
Gonis, Antonios; Daene, Markus W; Nicholson, Don M; Stocks, George Malcolm
2012-01-01
We have developed and tested in terms of atomic calculations an exact, analytic and computationally simple procedure for determining the functional derivative of the exchange energy with respect to the density in the implementation of the Kohn Sham formulation of density functional theory (KS-DFT), providing an analytic, closed-form solution of the self-interaction problem in KS-DFT. We demonstrate the efficacy of our method through ground-state calculations of the exchange potential and energy for atomic He and Be atoms, and comparisons with experiment and the results obtained within the optimized effective potential (OEP) method.
Ali, Farhad; Khan, Ilyas; Shafie, Sharidan
2014-01-01
Closed form solutions for unsteady free convection flows of a second grade fluid near an isothermal vertical plate oscillating in its plane using the Laplace transform technique are established. Expressions for velocity and temperature are obtained and displayed graphically for different values of Prandtl number Pr, thermal Grashof number Gr, viscoelastic parameter α, phase angle ωτ and time τ. Numerical values of skin friction τ0 and Nusselt number Nu are shown in tables. Some well-known solutions in literature are reduced as the limiting cases of the present solutions. PMID:24551033
Ultrafast ring-opening/closing and deactivation channels for a model spiropyran-merocyanine system.
Sanchez-Lozano, Marta; Estévez, Carlos Manuel; Esté vez, Carlos Manuel; Hermida-Ramón, Jose; Hermida-Ramó n, Jose; Serrano-Andres, Luis
2011-08-25
The photochemistry of a model merocyanine-spiropyran system was analyzed theoretically at the MS-CASPT2//SA-CASSCF(14,12) level. Several excited singlet states were studied in both the closed spiropyran and open merocyanine forms, and the paths to the different S(1)/S(0) conical intersections found were analyzed. After absorption of UV light from the spiropyran form, there are two possible ultrafast routes to efficient conversion to the ground state; one involves the rupture of the C(spiro)-O bond leading to the open form and the other involves the lengthening of the C(spiro)-N bond with no photoreaction. From the merocyanine side the excited state can reach a very broad S(1)/S(0) conical intersection region that leads the system to the closed form after rotation of the central methine bond. Alternatively, rotation of the other methine bonds connects the system through different S(1)/S(0) conical intersections to several merocyanine isomers. The present work provides a theoretical framework for the recent experimental results (Buback , J. J. Am. Chem. Soc. 2010, 132, 1610-1619) and sheds light on the complex photochemistry of these kinds of compounds.
NASA Technical Reports Server (NTRS)
Barnett, Alan R.; Widrick, Timothy W.; Ludwiczak, Damian R.
1995-01-01
Solving for the displacements of free-free coupled systems acted upon by static loads is commonly performed throughout the aerospace industry. Many times, these problems are solved using static analysis with inertia relief. This solution technique allows for a free-free static analysis by balancing the applied loads with inertia loads generated by the applied loads. For some engineering applications, the displacements of the free-free coupled system induce additional static loads. Hence, the applied loads are equal to the original loads plus displacement-dependent loads. Solving for the final displacements of such systems is commonly performed using iterative solution techniques. Unfortunately, these techniques can be time-consuming and labor-intensive. Since the coupled system equations for free-free systems with displacement-dependent loads can be written in closed-form, it is advantageous to solve for the displacements in this manner. Implementing closed-form equations in static analysis with inertia relief is analogous to implementing transfer functions in dynamic analysis. Using a MSC/NASTRAN DMAP Alter, displacement-dependent loads have been included in static analysis with inertia relief. Such an Alter has been used successfully to solve efficiently a common aerospace problem typically solved using an iterative technique.
Spencer, Steven J
2010-05-01
Closed-form analytical solutions are found for the time difference of arrival (TDOA) source location problem. Solutions are found for both two-dimensional (2D) and three-dimensional (3D) source location by formulating the TDOA equations in, respectively, polar and spherical coordinate systems, with the radial direction coincident with the assumed geodesic path of signal propagation to a reference sensor. Quadratic equations for TDOA 2D and 3D source location based on the spherical intersection (SX) scheme, in some cases permitting dual physical solutions, are found for three and four sensor element monitoring arrays, respectively. A method of spherical intersection subarrays (SXSAs) is developed to derive from these quadratic equations globally unique closed-form analytical solutions for TDOA 2D and 3D source location, for four and five sensor element monitoring arrays, respectively. Errors in 2D source location for introduced bias in time differences of arrival are shown to have a strong geometrical dependence. The SXSA and SX methods perform well in terms of accuracy and precision at high levels of arrival time bias for both 2D and 3D source location and are much more efficient than nonlinear least-squares schemes. The SXSA scheme may have particular applicability to accurately solving source location problems in demanding real-time situations.
A closed-form method for single-point positioning with six satellites in dual-GNSS constellations
NASA Astrophysics Data System (ADS)
Teng, Yunlong; Huang, Qi; Ao, Yongcai; Li, Yun
2016-12-01
With the impact of the Global Navigation Satellite System (GNSS), dual-GNSS constellations are playing an increasingly significant role in positioning, navigation and timing (PNT) applications. Aiming at improving from the existing method, i.e., linearization, of solving the single-point positioning problem under a dual-GNSS, this paper develops a closed-form method for solving PNT problems in the case of six satellites. This method reduces the positioning problem to a simple mathematical problem of finding solutions to a quadratic equation, thereby needing only one receiver clock bias (RCB) as variable. By solving the RCB, the positioning information in three dimensions is obtained by utilizing a linear equation. Compared with the existing method, the closed-form method requires no initial position or iterations. This method thus provides a direct solution to single-point positioning. Further, how to check the uniqueness and the validity of the solutions is also derived. Experimental results verify the validity, applicability and efficiency of the proposed method.
NASA Astrophysics Data System (ADS)
Schwadron, N. A.; Möbius, E.; Leonard, T.; Fuselier, S. A.; McComas, D. J.; Heirtzler, D.; Kucharek, H.; Rahmanifard, F.; Bzowski, M.; Kubiak, M. A.; Sokół, J. M.; Swaczyna, P.; Frisch, P.
2015-10-01
makes no assumptions or expansions with respect to the spin-axis pointing or frame of reference. Thus, we are able to move beyond closed-form approximations and utilize observations of interstellar He during the complete five year period from 2009 to 2013 when the primary component of interstellar He is most prominent. Chi-square minimization of simulations compared to observations results in a He ISN flow longitude of 75.°6 ± 1.°4, latitude of -5.°12 ± 0.°27, speed of 25.4 ± 1.1 km s-1, and temperature of 8000 ± 1300 K, where the uncertainties are related and apply along the IBEX parameter tube. This paper also provides documentation for a new release of ISN data and associated model runs.
12 CFR Appendix A to Part 40 - Model Privacy Form
Code of Federal Regulations, 2010 CFR
2010-01-01
... institution, including a group of financial institutions that use a common privacy notice, to meet the content... form is a standardized form, including page layout, content, format, style, pagination, and shading... appropriate. 2. The Contents of the Model Privacy Form The model form consists of two pages, which may...
12 CFR 40.2 - Model privacy form and examples.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Model privacy form and examples. 40.2 Section 40.2 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY PRIVACY OF CONSUMER FINANCIAL INFORMATION § 40.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in Appendix A of this...
12 CFR 216.2 - Model privacy form and examples.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 12 Banks and Banking 2 2010-01-01 2010-01-01 false Model privacy form and examples. 216.2 Section 216.2 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM PRIVACY OF CONSUMER FINANCIAL INFORMATION (REGULATION P) § 216.2 Model privacy form and examples. (a) Model privacy form. Use of the model privacy form...
Process Developed for Forming Urethane Ice Models
NASA Technical Reports Server (NTRS)
Vannuyen, Thomas
1998-01-01
A new process for forming ice shapes on an aircraft wing was developed at the NASA Lewis Research Center. The innovative concept was formed by Lewis' Icing Research Tunnel (IRT) team, and the hardware was manufactured by Lewis' Manufacturing Engineering Division. This work was completed to increase our understanding of the stability and control of aircraft during icing conditions. This project will also enhance our evaluation of true aerodynamic wind tunnel effects on aircraft. In addition, it can be used as a design tool for evaluating ice protection systems.
12 CFR 573.2 - Model privacy form and examples.
Code of Federal Regulations, 2012 CFR
2012-01-01
... 12 Banks and Banking 6 2012-01-01 2012-01-01 false Model privacy form and examples. 573.2 Section 573.2 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY PRIVACY OF CONSUMER FINANCIAL INFORMATION § 573.2 Model privacy form and examples. (a) Model privacy form. Use of the...
12 CFR 573.2 - Model privacy form and examples.
Code of Federal Regulations, 2014 CFR
2014-01-01
... 12 Banks and Banking 6 2014-01-01 2012-01-01 true Model privacy form and examples. 573.2 Section 573.2 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY PRIVACY OF CONSUMER FINANCIAL INFORMATION § 573.2 Model privacy form and examples. (a) Model privacy form. Use of the...
12 CFR 40.2 - Model privacy form and examples.
Code of Federal Regulations, 2011 CFR
2011-01-01
... 12 Banks and Banking 1 2011-01-01 2011-01-01 false Model privacy form and examples. 40.2 Section 40.2 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY PRIVACY OF CONSUMER FINANCIAL INFORMATION § 40.2 Model privacy form and examples. (a) Model privacy form. Use of the...
12 CFR 1016.2 - Model privacy form and examples.
Code of Federal Regulations, 2012 CFR
2012-01-01
... 12 Banks and Banking 8 2012-01-01 2012-01-01 false Model privacy form and examples. 1016.2 Section 1016.2 Banks and Banking BUREAU OF CONSUMER FINANCIAL PROTECTION PRIVACY OF CONSUMER FINANCIAL INFORMATION (REGULATION P) § 1016.2 Model privacy form and examples. (a) Model privacy form. Use of the...
12 CFR 573.2 - Model privacy form and examples.
Code of Federal Regulations, 2011 CFR
2011-01-01
... 12 Banks and Banking 5 2011-01-01 2011-01-01 false Model privacy form and examples. 573.2 Section 573.2 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY PRIVACY OF CONSUMER FINANCIAL INFORMATION § 573.2 Model privacy form and examples. (a) Model privacy form. Use of the...
12 CFR 573.2 - Model privacy form and examples.
Code of Federal Regulations, 2013 CFR
2013-01-01
... 12 Banks and Banking 6 2013-01-01 2012-01-01 true Model privacy form and examples. 573.2 Section 573.2 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY PRIVACY OF CONSUMER FINANCIAL INFORMATION § 573.2 Model privacy form and examples. (a) Model privacy form. Use of the...
12 CFR 40.2 - Model privacy form and examples.
Code of Federal Regulations, 2013 CFR
2013-01-01
... 12 Banks and Banking 1 2013-01-01 2013-01-01 false Model privacy form and examples. 40.2 Section 40.2 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY PRIVACY OF CONSUMER FINANCIAL INFORMATION § 40.2 Model privacy form and examples. (a) Model privacy form. Use of the...
12 CFR 573.2 - Model privacy form and examples.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Model privacy form and examples. 573.2 Section 573.2 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY PRIVACY OF CONSUMER FINANCIAL INFORMATION § 573.2 Model privacy form and examples. (a) Model privacy form. Use of the...
12 CFR 40.2 - Model privacy form and examples.
Code of Federal Regulations, 2014 CFR
2014-01-01
... 12 Banks and Banking 1 2014-01-01 2014-01-01 false Model privacy form and examples. 40.2 Section 40.2 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY PRIVACY OF CONSUMER FINANCIAL INFORMATION § 40.2 Model privacy form and examples. (a) Model privacy form. Use of the...
12 CFR 40.2 - Model privacy form and examples.
Code of Federal Regulations, 2012 CFR
2012-01-01
... 12 Banks and Banking 1 2012-01-01 2012-01-01 false Model privacy form and examples. 40.2 Section 40.2 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY PRIVACY OF CONSUMER FINANCIAL INFORMATION § 40.2 Model privacy form and examples. (a) Model privacy form. Use of the...
12 CFR 1016.2 - Model privacy form and examples.
Code of Federal Regulations, 2014 CFR
2014-01-01
... 12 Banks and Banking 8 2014-01-01 2014-01-01 false Model privacy form and examples. 1016.2 Section 1016.2 Banks and Banking BUREAU OF CONSUMER FINANCIAL PROTECTION PRIVACY OF CONSUMER FINANCIAL INFORMATION (REGULATION P) § 1016.2 Model privacy form and examples. (a) Model privacy form. Use of the...
12 CFR 1016.2 - Model privacy form and examples.
Code of Federal Regulations, 2013 CFR
2013-01-01
... 12 Banks and Banking 8 2013-01-01 2013-01-01 false Model privacy form and examples. 1016.2 Section 1016.2 Banks and Banking BUREAU OF CONSUMER FINANCIAL PROTECTION PRIVACY OF CONSUMER FINANCIAL INFORMATION (REGULATION P) § 1016.2 Model privacy form and examples. (a) Model privacy form. Use of the...
Deposit model for closed-basin potash-bearing brines
Orris, Greta J.
2011-01-01
Closed-basin potash-bearing brines are one of the types of potash deposits that are a source of potash production within the United States, as well as other countries. Though these deposits are of highly variable size, they are important sources of potash on a regional basis. In addition, these deposits have a high potential of co- and by-product production of one or more commodities such as lithium, boron, magnesium, and others.
Micromechanical Modeling of Metal Forming Operations
NASA Astrophysics Data System (ADS)
Van, Tung Phan; Jöchen, Katja; Böhlke, Thomas
2011-05-01
In this work, a ferritic stainless steel (DC04) is investigated in the following three steps. First, we use micropillar compression test data for the identification of a large strain single crystal plasticity model. In the second step the model is verified based on Electron Backscatter Diffraction (EBSD) measurements in a small specimen subjected to a large strain uniaxial tensile test. The two-dimensional EBSD data have been discretized by finite elements and subjected to homogeneous displacement boundary conditions for the second step. Finally, we apply a two-scale Taylor type model at the integration points of the finite elements to simulate the deep drawing process based on initial texture data. The texture data required for the specification of the two-scale model is determined based on the aforementioned EBSD data and by using a texture component method simultaneously to improve the computation time. The finite element simulations were performed with differently textured sheet metals and compared with experiment.
NASA Astrophysics Data System (ADS)
Xu, Tianhua; Jacobsen, Gunnar; Popov, Sergei; Li, Jie; Liu, Tiegen; Zhang, Yimo
2016-10-01
The performance of long-haul high speed coherent optical fiber communication systems is significantly degraded by the laser phase noise and the equalization enhanced phase noise (EEPN). In this paper, the analysis of the one-tap normalized least-mean-square (LMS) carrier phase recovery (CPR) is carried out and the close-form expression is investigated for quadrature phase shift keying (QPSK) coherent optical fiber communication systems, in compensating both laser phase noise and equalization enhanced phase noise. Numerical simulations have also been implemented to verify the theoretical analysis. It is found that the one-tap normalized least-mean-square algorithm gives the same analytical expression for predicting CPR bit-error-rate (BER) floors as the traditional differential carrier phase recovery, when both the laser phase noise and the equalization enhanced phase noise are taken into account.
NASA Astrophysics Data System (ADS)
Kudinov, I. V.; Kudinov, V. A.
2014-09-01
The differential equation of damped string vibrations was obtained with the finite speed of extension and strain propagation in the Hooke's law formula taken into account. In contrast to the well-known equations, the obtained equation contains the first and third time derivatives of the displacement and the mixed derivative with respect to the space and time variables. Separation of variables was used to obtain its exact closed-form solution, whose analysis showed that, for large values of the relaxation coefficient, the string return to the initial state after its escape from equilibrium is accompanied by high-frequency low-amplitude damped vibrations, which occur on the initial time interval only in the region of positive displacements. And in the limit, for some large values of the relaxation coefficient, the string return to the initial state occurs practically without any oscillatory process.
NASA Technical Reports Server (NTRS)
Smith, R. L.
1978-01-01
Closed-form equations for the lift, drag, and pitching moment coefficients of two dimensional airfoil sections in steady subsonic flow were obtained from published theoretical and experimental results. A turbulent boundary layer was assumed to exist on the airfoil surfaces. The effects of section angle of attack, Mach number, Reynolds number, and the specific airfoil type were considered. The equations were applicable through an angle of attack range of -180 deg to +180 deg; however, above about + or - 20 deg, the section characteristics were assumed to be functions only of angle of attack. A computer program is presented which evaluates the equations for a range of Mach numbers and angles of attack. Calculated results for the NACA 23012 airfoil section were compared with experimental data.
Alqasemi, Umar; Salehi, Hassan S.; Zhu, Quing
2016-01-01
This paper reports a method of estimating an approximate closed-form solution to the light diffusion equation for any type of geometry involving Dirichlet’s boundary condition with known source location. It is based on estimating the optimum locations of multiple imaginary point sources to cancel the fluence at the extrapolated boundary by constrained optimization using a genetic algorithm. The mathematical derivation of the problem to approach the optimum solution for the direct-current type of diffuse optical systems is described in detail. Our method is first applied to slab geometry and compared with a truncated series solution. After that, it is applied to hemispherical geometry and compared with Monte Carlo simulation results. The method provides a fast and sufficiently accurate fluence distribution for optical reconstruction. PMID:26831771
16 CFR Appendix A to Part 313 - Model Privacy Form
Code of Federal Regulations, 2010 CFR
2010-01-01
... of financial institutions that use a common privacy notice, to meet the content requirements of the... standardized form, including page layout, content, format, style, pagination, and shading. Institutions seeking... Contents of the Model Privacy Form The model form consists of two pages, which may be printed on both...
12 CFR Appendix B to Part 202 - Model Application Forms
Code of Federal Regulations, 2010 CFR
2010-01-01
... 12 Banks and Banking 2 2010-01-01 2010-01-01 false Model Application Forms B Appendix B to Part 202 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM EQUAL CREDIT OPPORTUNITY ACT (REGULATION B) Pt. 202, App. B Appendix B to Part 202—Model Application Forms 1. This appendix contains five model...
A Bayesian study of the primordial power spectrum from a novel closed universe model
NASA Astrophysics Data System (ADS)
Vázquez, J. Alberto; Lasenby, A. N.; Bridges, M.; Hobson, M. P.
2012-05-01
We constrain the shape of the primordial power spectrum using recent measurements of the cosmic microwave background (CMB) from the Wilkinson Microwave Anisotropy Probe (WMAP) 7-year data and other high-resolution CMB experiments. We also include observations of the matter power spectrum from the luminous red galaxy (LRG) subset DR7 of the Sloan Digital Sky Survey (SDSS). We consider two different models of the primordial power spectrum. The first is the standard nearly scale-invariant spectrum in the form of a generalized power-law parametrized in terms of the spectral amplitude As, the spectral index ns and (possibly) the running parameter nrun. The second spectrum is derived from the Lasenby and Doran (LD) model. The LD model is based on the restriction of the total conformal time available in a closed Universe and the predicted primordial power spectrum depends upon just two parameters. An important feature of the LD spectrum is that it naturally incorporates an exponential fall-off on large scales, which might provide a possible explanation for the lower-than-expected power observed at low multipoles in the CMB. In addition to parameter estimation, we compare both models using Bayesian model selection. We find there is a significant preference for the LD model over a simple power-law spectrum for a CMB-only data set, and over models with an equal number of parameters for all the data sets considered.
[The model of resting forms of mycobacteria for testing of drugs for latent forms of tuberculosis].
Anuchin, A M; Goncharenko, A V; Galon, I V; Demidenok, O I; Kudykina, Iu K; Moĭsenovich, M M; Muliukin, A L; Kaprel'iants, A S
2010-01-01
The new model of obtaining of ovoid resting forms Mycobacterium smegmatis, which are morphologically different from vegetative (rod-like) cells, was developed. Ovoid forms were characterized by a drastically decreased level of metabolic activity, an increased stability to heat processing and antibiotics action, and also by prolonged (more than 2 months) storage time preserving colony-forming ability. Obtained resting forms of mycobacteria may be used in test-systems for checking efficiency of new medical agents against latent forms of tuberculosis and determination of role of these of those genes in entering rest state.
Individualized Cognitive Modeling for Close-Loop Task Mitigation
NASA Technical Reports Server (NTRS)
Zhang, Guangfan; Xu, Roger; Wang, Wei; Li, Jiang; Schnell, Tom; Keller, Mike
2010-01-01
An accurate real-time operator functional state assessment makes it possible to perform task management, minimize risks, and improve mission performance. In this paper, we discuss the development of an individualized operator functional state assessment model that identifies states likely leading to operational errors. To address large individual variations, we use two different approaches to build a model for each individual using its data as well as data from subjects with similar responses. If a subject's response is similar to that of the individual of interest in a specific functional state, all the training data from this subject will be used to build the individual model. The individualization methods have been successfully verified and validated with a driving test data set provided by University of Iowa. With the individualized models, the mean squared error can be significantly decreased (by around 20%).
Quantization of closed mini-superspace models as bound states
NASA Astrophysics Data System (ADS)
Kung, J. H.
1995-01-01
The Wheeler-DeWitt equation is applied to closedk>0 Friedmann-Robertson-Walker metric with various combination of cosmological constant and matter (e.g., radiation or pressureless gas). It is shown that if the universe ends in the matter dominated era (e.g., radiation or pressureless gas) with zero cosmological constant, then the resulting Wheeler-DeWitt equation describes a bound state problem. As solutions of a nondegenerate bound state system, the eigen-wave functions are real (Hartle-Hawking). Furthermore, as a bound state problem, there exists a quantization condition that relates the curvature of the three space with the various energy densities of the universe. If we assume that our universe is closed, then the quantum number of our universe isN˜(Gk)-1˜10122. The largeness of this quantum number is naturally explained by an early inflationary phase which resulted in a flat universe we observe today. It is also shown that if there is a cosmological constant Λ>0 in our universe that persists for all time, then the resulting Wheeler-DeWitt equation describes a non-bound state system, regardless of the magnitude of the cosmological constant. As a consequence, the wave functions are in general complex (Vilenkin).
Photometric Modelling of Close Binary Star CN And
NASA Astrophysics Data System (ADS)
Jassur, D. M. Z.; Khodadadi, A.
2006-03-01
The results of two color photometry of active close binary CN And are presented and analyzed. The light curves of the system are obviously asymmetric, with the primary maximum brighter than the sec-ondary maximum, which is known as the O'Conell effect. The most plau-sible explanation of the asymmetry is expected to be due to spot activity of the primary component. For the determination of physical and geometrical parameters, the most new version of W--D code was used, but the presence of asymmetry prevented the convergence of the method when the whole light curves were used. The solutions were obtained by applying mode 3 of W--D code to the first half of the light curves, assuming synchronous rota-tion and zero eccentricity. Absolute parameters of the system were obtained from combining the photometric solution with spectroscopic data obtained from radial velocity curve analysis. The results indicate the poor thermal contact of the components and transit primary minimum. Finally the O--C diagram was analyzed. It was found that the orbital period of the system is changing with a rate of dP/dt =-2 2 6-10??? 10 which corresponds to mass transfer from more massive component to less massive with the rate of dM/dt ?4 82-10??? 8 M sun year.
NASA Astrophysics Data System (ADS)
Ausserlechner, Udo
2016-02-01
Sheet resistance and Hall mobility are commonly measured by Van der Pauw's method. Closed form expressions are known for four point-sized contacts. Recently, for devices with fourfold rotational symmetry a closed form expression for the sheet resistance was given for contacts of arbitrary size. In this paper we discuss its accuracy, link it to the equivalent circuit diagram of the device, and add another expression that determines the Hall mobility with 0.02% accuracy.
Modeling and control for closed environment plant production systems
NASA Technical Reports Server (NTRS)
Fleisher, David H.; Ting, K. C.; Janes, H. W. (Principal Investigator)
2002-01-01
A computer program was developed to study multiple crop production and control in controlled environment plant production systems. The program simulates crop growth and development under nominal and off-nominal environments. Time-series crop models for wheat (Triticum aestivum), soybean (Glycine max), and white potato (Solanum tuberosum) are integrated with a model-based predictive controller. The controller evaluates and compensates for effects of environmental disturbances on crop production scheduling. The crop models consist of a set of nonlinear polynomial equations, six for each crop, developed using multivariate polynomial regression (MPR). Simulated data from DSSAT crop models, previously modified for crop production in controlled environments with hydroponics under elevated atmospheric carbon dioxide concentration, were used for the MPR fitting. The model-based predictive controller adjusts light intensity, air temperature, and carbon dioxide concentration set points in response to environmental perturbations. Control signals are determined from minimization of a cost function, which is based on the weighted control effort and squared-error between the system response and desired reference signal.
Modelling of Genetically Engineered Microorganisms Introduction in Closed Artificial Microcosms
NASA Astrophysics Data System (ADS)
Pechurkin, N. S.; Brilkov, A. V.; Ganusov, V. V.; Kargatova, T. V.; Maksimova, E. E.; Popova, L. Yu.
1999-01-01
The possibility of introducing genetically engineered microorganisms (GEM) into simple biotic cycles of laboratory water microcosms was investigated. The survival of the recombinant strain Escherichia coli Z905 (Apr, Lux+) in microcosms depends on the type of model ecosystems. During the absence of algae blooming in the model ecosystem, the part of plasmid-containing cells E. coli decreased fast, and the structure of the plasmid was also modified. In conditions of algae blooming (Ankistrodesmus sp.) an almost total maintenance of plasmid-containing cells was observed in E.coli population. A mathematics model of GEM's behavior in water ecosystems with different level of complexity has been formulated. Mechanisms causing the difference in luminescent exhibition of different species are discussed, and attempts are made to forecast the GEM's behavior in water ecosystems.
Federal Register 2010, 2011, 2012, 2013, 2014
2013-08-12
... COMMISSION 47 CFR Part 54 Wireline Competition Bureau Announces Closing of the Bureau's Cost Model Virtual Workshop AGENCY: Federal Communications Commission. ACTION: Proposed Rule; closing of virtual workshop... America Cost Model (CAM) virtual workshop. Parties should submit any additional input regarding the...
Horken, K M; Tabita, F R
1999-01-15
The deduced primary sequence (cbbL and cbbS) of form I ribulose 1, 5-bisphosphate carboxylase/oxygenase (rubisco) from Bradyrhizobium japonicum places this enzyme within the Type IC subgroup of red-like rubisco enzymes. In addition, B. japonicum appears to organize most of the structural genes of the Calvin-Benson-Bassham (CBB) pathway in at least one major operon. Functional expression and characterization of the B. japonicum and Xanthobacter flavus enzymes from this group revealed that these molecules exhibit diverse kinetic properties despite their relatively high degree of sequence relatedness. Of prime importance was the fact that these closely related enzymes exhibited CO2 and O2 substrate specificities that varied from relatively low values [tau = (VcKo)/(VoKc) = 45] to values that approximated those obtained for higher plants (tau = 75). These results, combined with the metabolic and genetic versatility of the organisms from which these enzymes were derived, suggest a potential rich resource for future biological selection and structure-function studies aimed at elucidating structural features that govern key enzymological properties of rubisco.
Johnston, Iain G; Jones, Nick S
2015-08-08
Stochastic dynamics govern many important processes in cellular biology, and an underlying theoretical approach describing these dynamics is desirable to address a wealth of questions in biology and medicine. Mathematical tools exist for treating several important examples of these stochastic processes, most notably gene expression and random partitioning at single-cell divisions or after a steady state has been reached. Comparatively little work exists exploring different and specific ways that repeated cell divisions can lead to stochastic inheritance of unequilibrated cellular populations. Here we introduce a mathematical formalism to describe cellular agents that are subject to random creation, replication and/or degradation, and are inherited according to a range of random dynamics at cell divisions. We obtain closed-form generating functions describing systems at any time after any number of cell divisions for binomial partitioning and divisions provoking a deterministic or random, subtractive or additive change in copy number, and show that these solutions agree exactly with stochastic simulation. We apply this general formalism to several example problems involving the dynamics of mitochondrial DNA during development and organismal lifetimes.
NASA Astrophysics Data System (ADS)
Chesnaux, R.
2016-04-01
Closed-form analytical solutions for assessing the consequences of sea-level rise on fresh groundwater oceanic island lenses are provided for the cases of both strip and circular islands. Solutions are proposed for directly calculating the change in the thickness of the lens, the changes in volume and the changes in travel time of fresh groundwater within island aquifers. The solutions apply for homogenous aquifers recharged by surface infiltration and discharged by a down-gradient, fixed-head boundary. They also take into account the inland shift of the ocean due to land surface inundation, this shift being determined by the coastal slope of inland aquifers. The solutions are given for two simple island geometries: circular islands and strip islands. Base case examples are presented to illustrate, on one hand, the amplitude of the change of the fresh groundwater lens thickness and the volume depletion of the lens in oceanic island with sea-level rise, and on the other hand, the shortening of time required for groundwater to discharge into the ocean. These consequences can now be quantified and may help decision-makers to anticipate the effects of sea-level rise on fresh groundwater availability in oceanic island aquifers.
Johnston, Iain G.; Jones, Nick S.
2015-01-01
Stochastic dynamics govern many important processes in cellular biology, and an underlying theoretical approach describing these dynamics is desirable to address a wealth of questions in biology and medicine. Mathematical tools exist for treating several important examples of these stochastic processes, most notably gene expression and random partitioning at single-cell divisions or after a steady state has been reached. Comparatively little work exists exploring different and specific ways that repeated cell divisions can lead to stochastic inheritance of unequilibrated cellular populations. Here we introduce a mathematical formalism to describe cellular agents that are subject to random creation, replication and/or degradation, and are inherited according to a range of random dynamics at cell divisions. We obtain closed-form generating functions describing systems at any time after any number of cell divisions for binomial partitioning and divisions provoking a deterministic or random, subtractive or additive change in copy number, and show that these solutions agree exactly with stochastic simulation. We apply this general formalism to several example problems involving the dynamics of mitochondrial DNA during development and organismal lifetimes. PMID:26339194
NASA Astrophysics Data System (ADS)
Shang, Xiang-Yu; Yang, Chen; Zhou, Guo-Qing
2015-10-01
Efficient calculation of the electrostatic interactions including repulsive force between charged molecules in a biomolecule system or charged particles in a colloidal system is necessary for the molecular scale or particle scale mechanical analyses of these systems. The electrostatic repulsive force depends on the mid-plane potential between two charged particles. Previous analytical solutions of the mid-plane potential, including those based on simplified assumptions and modern mathematic methods, are reviewed. It is shown that none of these solutions applies to wide ranges of inter-particle distance from 0 to 10 and surface potential from 1 to 10. Three previous analytical solutions are chosen to develop a semi-analytical solution which is proven to have more extensive applications. Furthermore, an empirical closed-form expression of mid-plane potential is proposed based on plenty of numerical solutions. This empirical solution has extensive applications, as well as high computational efficiency. Project supported by the National Key Basic Research Program of China (Grant No. 2012CB026103), the National Natural Science Foundation of China (Grant No. 51009136), and the Natural Science Foundation of Jiangsu Province, China (Grant No. BK2011212).
Closed-loop Habitation Air Revitalization Model for Regenerative Life Support Systems
NASA Technical Reports Server (NTRS)
Hart, Maxwell M.
1991-01-01
The primary function of any life support system is to keep the crew alive by providing breathable air, potable water, edible food, and for disposal of waste. In a well-balanced or regenerative life support system, the various components are each using what is available and producing what is needed by other components so that there will always be enough chemicals in the form in which they are needed. Humans are not just users, but also one of the participating parts of the system. If a system could continuously recycle the original chemicals, this would make it virtually a Closed-loop Habitation (CH). Some difficulties in trying to create a miniature version of a CH are briefly discussed. In a miniature CH, a minimal structure must be provided and the difference must be made up by artificial parts such as physicochemical systems that perform the conversions that the Earth can achieve naturally. To study the interactions of these parts, a computer model was designed that simulates a miniature CH with emphasis on the air revitalization part. It is called the Closed-loop Habitation Air Revitalization Model (CHARM).
Negative binomial models for abundance estimation of multiple closed populations
Boyce, Mark S.; MacKenzie, Darry I.; Manly, Bryan F.J.; Haroldson, Mark A.; Moody, David W.
2001-01-01
Counts of uniquely identified individuals in a population offer opportunities to estimate abundance. However, for various reasons such counts may be burdened by heterogeneity in the probability of being detected. Theoretical arguments and empirical evidence demonstrate that the negative binomial distribution (NBD) is a useful characterization for counts from biological populations with heterogeneity. We propose a method that focuses on estimating multiple populations by simultaneously using a suite of models derived from the NBD. We used this approach to estimate the number of female grizzly bears (Ursus arctos) with cubs-of-the-year in the Yellowstone ecosystem, for each year, 1986-1998. Akaike's Information Criteria (AIC) indicated that a negative binomial model with a constant level of heterogeneity across all years was best for characterizing the sighting frequencies of female grizzly bears. A lack-of-fit test indicated the model adequately described the collected data. Bootstrap techniques were used to estimate standard errors and 95% confidence intervals. We provide a Monte Carlo technique, which confirms that the Yellowstone ecosystem grizzly bear population increased during the period 1986-1998.
Pulsar average wave forms and hollow-cone beam models
NASA Technical Reports Server (NTRS)
Backer, D. C.
1976-01-01
Pulsar wave forms have been analyzed from observations conducted over a wide radio-frequency range to assess the wave-form morphologies and to measure wave-form widths. The results of the analysis compare favorably with the predictions of a model with a hollow-cone beam of fixed dimensions and with random orientation of both the observer and the cone axis with respect to the pulsar spin axis. A class of three-component wave forms is included in the model by adding a central pencil beam to the hollow-cone hypothesis. The consequences of a number of discrepancies between observations and quantitative predictions of the model are discussed.
Closed-Loop Brain Model of Neocortical Information-Based Exchange
Kozloski, James
2016-01-01
Here we describe an “information-based exchange” model of brain function that ascribes to neocortex, basal ganglia, and thalamus distinct network functions. The model allows us to analyze whole brain system set point measures, such as the rate and heterogeneity of transitions in striatum and neocortex, in the context of neuromodulation and other perturbations. Our closed-loop model is grounded in neuroanatomical observations, proposing a novel “Grand Loop” through neocortex, and invokes different forms of plasticity at specific tissue interfaces and their principle cell synapses to achieve these transitions. By implementing a system for maximum information-based exchange of action potentials between modeled neocortical areas, we observe changes to these measures in simulation. We hypothesize that similar dynamic set points and modulations exist in the brain's resting state activity, and that different modifications to information-based exchange may shift the risk profile of different component tissues, resulting in different neurodegenerative diseases. This model is targeted for further development using IBM's Neural Tissue Simulator, which allows scalable elaboration of networks, tissues, and their neural and synaptic components toward ever greater complexity and biological realism. PMID:26834573
A mathematical model on the closing and opening mechanism for venus flytrap.
Yang, Ruoting; Lenaghan, Scott C; Zhang, Mingjun; Xia, Lijin
2010-08-01
This paper investigates the opening and closing mechanism for the Venus Flytrap (Dionaea muscipula). A mathematical model has been proposed to explain how the flytrap transitions between open, semi-closed, and closed states. The model accounts for the charge accumulation of action potentials, which generated by mechanical stimulation of the sensitive trigger hairs on the lobes of the flytrap. Though many studies have been reported for the Venus flytrap opening and closing mechanism, this paper attempts to explain the mechanism from nonlinear dynamics and control perspective.
Pis'man, T I; Pechurkin, N S; Sarangova, A B; Somova, L A
1999-01-01
Experimental models of small biotic cycles of different degree of closure and complexity with spatially separated components based on unicellular organisms have been studied. Gas closure of components looped into "autotroph-heterotroph" (chlorella-yeast) system doubled the lifetime of the system (as opposed to individually cultivated components). Higher complexity of the heterotroph component consisting of two yeast species also increased the lifetime of the system through more complete utilization of the substrate by competing yeast species. The lifetime of gas and substrate closed "producer-consumer" trophic chain (chlorella-paramecia) increased to 7 months. In 60 days the components' numbers reached their steady state followed by more than 40 cycles of the medium. The role of a predator organism (protozoan) in nitrogen cycling was demonstrated; reproduction of protozoa correlated directly with their emission of nitrogen in the ammonia form that is most optimum for growth of chlorella.
Electromagnetic Form Factors of the Nucleon in Chiral Soliton Models
NASA Astrophysics Data System (ADS)
Holzwarth, Gottfried
The ratio of electric to magnetic proton form factors {G_E^P}/{G_M^P} as measured in polarization transfer experiments shows a characteristic linear decrease with increasing momentum transfer Q2(< 10 (GeV/c)2). We present a simple argument how such a decrease arises naturally in chiral soliton models. For a detailed comparison of model results with experimentally determined form factors it is necessary to employ a boost from the soliton rest frame to the Breit frame. To enforce asymptotic counting rules for form factors, the model must be supplemented by suitably chosen interpolating powers n in the boost prescription. Within the minimal π-ϱ-ω soliton model, with the same n for both, electric and magnetic form factors, it is possible to obtain a very satisfactory fit to all available proton data for the magnetic form factor and to the recent polarization results for the ratio {G_E^P}/{G_M^P}. At the same time the small and very sensitive neutron electric form factor is reasonably well reproduced. The results show a systematic discrepancy with presently available data for the neutron magnetic form factor {G_M^n } for Q2 > 1 (GeV/c)2 for Q2 > 1 (GeV/c)2. We additionally comment on the possibility to extract information about the form factors in the time-like region and on two-photon exchange contributions to unpolarized elastic scattering which specifically arise in soliton models.
A Model for Short Gamma-Ray Bursts: Heated Neutron Stars in Close Binary Systems
NASA Astrophysics Data System (ADS)
Salmonson, Jay D.; Wilson, James R.
2003-04-01
In this paper we present a model for the short (< second) population of gamma-ray bursts (GRBs). In this model heated neutron stars in a close binary system near their last stable orbit emit neutrinos at large luminosities (~ 1053 ergs/sec). A fraction of these neutrinos will annihilate to form an e+e
31 CFR 50.17 - Use of model forms.
Code of Federal Regulations, 2011 CFR
2011-07-01
... 31 Money and Finance: Treasury 1 2011-07-01 2011-07-01 false Use of model forms. 50.17 Section 50.17 Money and Finance: Treasury Office of the Secretary of the Treasury TERRORISM RISK INSURANCE.... These forms may be found on the Treasury Web site at http://www.treasury.gov/trip....
31 CFR 50.17 - Use of model forms.
Code of Federal Regulations, 2014 CFR
2014-07-01
... 31 Money and Finance: Treasury 1 2014-07-01 2014-07-01 false Use of model forms. 50.17 Section 50.17 Money and Finance: Treasury Office of the Secretary of the Treasury TERRORISM RISK INSURANCE.... These forms may be found on the Treasury Web site at http://www.treasury.gov/trip....
31 CFR 50.17 - Use of model forms.
Code of Federal Regulations, 2013 CFR
2013-07-01
... 31 Money and Finance: Treasury 1 2013-07-01 2013-07-01 false Use of model forms. 50.17 Section 50.17 Money and Finance: Treasury Office of the Secretary of the Treasury TERRORISM RISK INSURANCE.... These forms may be found on the Treasury Web site at http://www.treasury.gov/trip....
31 CFR 50.17 - Use of model forms.
Code of Federal Regulations, 2012 CFR
2012-07-01
... 31 Money and Finance: Treasury 1 2012-07-01 2012-07-01 false Use of model forms. 50.17 Section 50.17 Money and Finance: Treasury Office of the Secretary of the Treasury TERRORISM RISK INSURANCE.... These forms may be found on the Treasury Web site at http://www.treasury.gov/trip....
Submission Form for Peer-Reviewed Cancer Risk Prediction Models
If you have information about a peer-reviewd cancer risk prediction model that you would like to be considered for inclusion on this list, submit as much information as possible through the form on this page.
NASA Technical Reports Server (NTRS)
Baron, S.; Muralidharan, R.; Kleinman, D. L.
1978-01-01
The optimal control model of the human operator is used to develop closed loop models for analyzing the effects of (digital) simulator characteristics on predicted performance and/or workload. Two approaches are considered: the first utilizes a continuous approximation to the discrete simulation in conjunction with the standard optimal control model; the second involves a more exact discrete description of the simulator in a closed loop multirate simulation in which the optimal control model simulates the pilot. Both models predict that simulator characteristics can have significant effects on performance and workload.
31 CFR 50.17 - Use of model forms.
Code of Federal Regulations, 2010 CFR
2010-07-01
... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Use of model forms. 50.17 Section 50.17 Money and Finance: Treasury Office of the Secretary of the Treasury TERRORISM RISK INSURANCE PROGRAM Disclosures as Conditions for Federal Payment § 50.17 Use of model forms. (a) Policies in force on the date of enactment. (1) An insurer that...
Atmosphere Behavior in Gas-Closed Mouse-Algal Systems: An Experimental and Modelling Study
NASA Technical Reports Server (NTRS)
Averner, M. M.; Moore, B., III; Bartholomew, I.; Wharton, R.
1985-01-01
A dual approach of mathematical modelling and laboratory experimentation aimed at examining the gas exchange characteristics of artificial animal/plant systems closed to the ambient atmosphere was initiated. The development of control techniques and management strategies for maintaining the atmospheric levels of carbon dioxide and oxygen at physiological levels is examined. A mathematical model simulating the atmospheric behavior in these systems was developed and an experimental gas closed system was constructed. These systems are described and preliminary results are presented.
Damage prediction in incremental forming by using Lemaitre damage model
NASA Astrophysics Data System (ADS)
Wu, Shenghua; Reis, Ana; Teixeira, Pedro; da Rocha, A. Barata; Lino, Jorge
2012-09-01
Incremental forming is an innovative flexible method used for manufacturing of the sheet metal products and brings a great insight for the small-batch-size or customized sheet products. Some experiments show that incremental sheet metal forming can undergo higher deformations than traditional sheet metal forming. The traditional method to evaluate formability like forming limit curve (FLD) etc can't give the right answer in incremental forming which is subjected to highly non-monotonic serrated strain paths. In this paper, the Lemaitre' damage model is presented and fully coupled with finite element simulation in commercial software ABAQUS to predict the failure in incremental forming. Results show that the prediction makes a great agreement with the relevant experiments.
NASA Astrophysics Data System (ADS)
Derbenev, I. V.; Chizhkova, N. E.; Sapozhnikov, F. A.; Dremov, V. V.
We use molecular dynamics for modelling properties of carbon nanoclusters. The size of modelled carbon nanoclusters is below 5 nm, which is typical of detonation diamond nanoclusters. We have found their structural changes at P = 0 to be as follows: Diamond → Diamond core + GL-surface → sandwich-type graphite → Graphite-like liquid. In smaller clusters the transformations start at a lower temperature. Adaptive Template Analysis (ATA) was used to determine the structures. We studied evaporation properties at temperatures above 5000 K. For clusters of several thousands of atoms, the simple dependence kvap ˜ e-T0/T/N1/3 (T0 is constant) is quite good. It has been found out that densities of saturated vapour for clusters containing from 4000 to 8000 atoms are very close at T = 5000 K. The structure of nanoclusters was studied at nonzero pressures set by an argon environment. Calculated results suggest that the patterns for different temperatures are qualitatively similar for three pressures under study (20, 25 and 30 GPa). At T = 1000-1500 K, the initial diamond core is preserved and a thin disordered GL layer is present on the surface. At T = 2000-5000 K, graphite grains form in the sample and a thin layer of liquid is present on its surface. The sample is amorphous at 5500 K and 6000 K. The prevalence of the graphite phase at these pressures seems to come from the absence of long-range interaction in REBO-2002.
Development of a Prototype Model-Form Uncertainty Knowledge Base
NASA Technical Reports Server (NTRS)
Green, Lawrence L.
2016-01-01
Uncertainties are generally classified as either aleatory or epistemic. Aleatory uncertainties are those attributed to random variation, either naturally or through manufacturing processes. Epistemic uncertainties are generally attributed to a lack of knowledge. One type of epistemic uncertainty is called model-form uncertainty. The term model-form means that among the choices to be made during a design process within an analysis, there are different forms of the analysis process, which each give different results for the same configuration at the same flight conditions. Examples of model-form uncertainties include the grid density, grid type, and solver type used within a computational fluid dynamics code, or the choice of the number and type of model elements within a structures analysis. The objectives of this work are to identify and quantify a representative set of model-form uncertainties and to make this information available to designers through an interactive knowledge base (KB). The KB can then be used during probabilistic design sessions, so as to enable the possible reduction of uncertainties in the design process through resource investment. An extensive literature search has been conducted to identify and quantify typical model-form uncertainties present within aerospace design. An initial attempt has been made to assemble the results of this literature search into a searchable KB, usable in real time during probabilistic design sessions. A concept of operations and the basic structure of a model-form uncertainty KB are described. Key operations within the KB are illustrated. Current limitations in the KB, and possible workarounds are explained.
Cracks and blisters formed close to a silicon wafer surface by He-H co-implantation at low energy
Cherkashin, N. Darras, F.-X.; Claverie, A.; Daghbouj, N.; Fnaiech, M.
2015-12-28
We have studied the effect of reducing the implantation energy towards low keV values on the areal density of He and H atoms stored within populations of blister cavities formed by co-implantation of the same fluence of He then H ions into Si(001) wafers and annealing. Using a variety of experimental techniques, we have measured blister heights and depth from the surface, diameter, areal density of the cracks from which they originate as functions of implantation energy and fluence. We show that there is a direct correlation between the diameters of the cracks and the heights of the associated blisters. This correlation only depends on the implantation energy, i.e., only on the depth at which the cracks are located. Using finite element method modeling, we infer the pressure inside the blister cavities from the elastic deformations they generate, i.e., from the height of the blisters. From this, we demonstrate that the gas pressure within a blister only depends on the diameter of the associated crack and not on its depth position and derive an analytical expression relating these parameters. Relating the pressure inside a blister to the respective concentrations of gas molecules it contains, we deduce the areal densities of He and H atoms contained within the populations of blisters. After low-energy implantations (8 keV He{sup +}, 3 keV H{sup +}), all the implanted He and H atoms contribute to the formation of the blisters. There is no measurable exo-diffusion of any of the implanted gases, in contrast to what was assumed at the state of the art to explain the failure of the Smart-Cut technology when using very low energy ion implantation for the fabrication of ultra-thin layers. Alternative explanations must be investigated.
Cracks and blisters formed close to a silicon wafer surface by He-H co-implantation at low energy
NASA Astrophysics Data System (ADS)
Cherkashin, N.; Daghbouj, N.; Darras, F.-X.; Fnaiech, M.; Claverie, A.
2015-12-01
We have studied the effect of reducing the implantation energy towards low keV values on the areal density of He and H atoms stored within populations of blister cavities formed by co-implantation of the same fluence of He then H ions into Si(001) wafers and annealing. Using a variety of experimental techniques, we have measured blister heights and depth from the surface, diameter, areal density of the cracks from which they originate as functions of implantation energy and fluence. We show that there is a direct correlation between the diameters of the cracks and the heights of the associated blisters. This correlation only depends on the implantation energy, i.e., only on the depth at which the cracks are located. Using finite element method modeling, we infer the pressure inside the blister cavities from the elastic deformations they generate, i.e., from the height of the blisters. From this, we demonstrate that the gas pressure within a blister only depends on the diameter of the associated crack and not on its depth position and derive an analytical expression relating these parameters. Relating the pressure inside a blister to the respective concentrations of gas molecules it contains, we deduce the areal densities of He and H atoms contained within the populations of blisters. After low-energy implantations (8 keV He+, 3 keV H+), all the implanted He and H atoms contribute to the formation of the blisters. There is no measurable exo-diffusion of any of the implanted gases, in contrast to what was assumed at the state of the art to explain the failure of the Smart-Cut technology when using very low energy ion implantation for the fabrication of ultra-thin layers. Alternative explanations must be investigated.
Hydrological Modeling of the Jezero Crater Outlet-Forming Flood
NASA Technical Reports Server (NTRS)
Fassett, C. I.; Goudge, T. A.
2017-01-01
Abundant evidence exists for lakes on Mars both from orbital observations [e.g., 1-3] and in situ exploration [e.g., 4-5]. These lakes can be divided into two classes: those that were hydrologically closed, so their source valley(s) terminated at the basin [3], and those that were hydrologically open, where there was sufficient flow from inlet valley(s) to cause the lake to breach and form an outlet valley [2]. It is easier to be confident from orbital data alone that a standing body of water must have existed in open basins, because there is no other way for their perched outlet valleys to form. The majority of basins fed by valley networks, rather than by isolated inlet valleys, are open [6], with some important exceptions (e.g., Gale Crater). Jezero crater (Fig. 1) is one of the most well-studied open basin paleolakes on Mars, with a breach that re-mains well above the lowest part of the crater floor, and two sedimentary fans at its northwestern margin that are likely deltaic in origin [7-9]. CRISM observations of these sediments indicate they host a variety of alteration minerals [9-11], including smectite and carbonate, and both the mineralogy of the sediments and their settings suggest they have a strong potential for preserving organic materials [10]. As a result, Jezero is a strong candidate landing site for the Mars 2020 rover. Approximate formative discharges have been estimated for its well-preserved western fan (Q approximately 500m3/s) [7], but to our knowledge, no estimates for the dis-charges associated with formation and incision of its outlet valley have been presented. Indeed, only a few studies [e.g., 12-14] have attempted to reconstruct the formation of outlet breaches broadly similar to Jezero anywhere on Mars, despite the apparent commonality of basins with large outlets [e.g., 2]. The outlet valley formed as a dam breach when the lake overflowed. In such an event, the growth and incision of the breach is directly coupled to flood discharge
Atmosphere behavior in gas-closed mouse-algal systems - An experimental and modelling study
NASA Technical Reports Server (NTRS)
Averner, M. M.; Moore, B., III; Bartholomew, I.; Wharton, R.
1984-01-01
A NASA-sponsored research program initiated using mathematical modelling and laboratory experimentation aimed at examining the gas-exchange characteristics of artificial animal/plant systems closed to the ambient atmosphere is studied. The development of control techniques and management strategies for maintaining the atmospheric levels of carbon dioxide and oxygen at physiological levels is considered. A mathematical model simulating the behavior of a gas-closed mouse-algal system under varying environmental conditions is described. To verify and validate the model simulations, an analytical system with which algal growth and gas exchange characteristics can be manipulated and measured is designed, fabricated, and tested. The preliminary results are presented.
Analytic Model For Estimation Of Cold Bulk Metal Forming Simulations
Skunca, Marko; Keran, Zdenka; Math, Miljenko
2007-05-17
Numerical simulation of bulk metal forming plays an important role in predicting a key parameters in cold forging. Comparison of numerical and experimental data is of great importance, but there is always a need of more universal analytical tools. Therefore, many papers besides experiment and simulation of a particular bulk metal forming technology, include an analytic model. In this paper an analytical model for evaluation of commercially available simulation program packages is proposed. Based on elementary theory of plasticity, being only geometry dependent, model represents a good analytical reference to estimate given modeling preferences like; element types, solver, remeshing influence and many others. Obtained, geometry dependent, stress fields compared with numerical data give a clear picture of numerical possibilities and limitations of particular modeling program package.
Simulation of root forms using cellular automata model
Winarno, Nanang Prima, Eka Cahya; Afifah, Ratih Mega Ayu
2016-02-08
This research aims to produce a simulation program for root forms using cellular automata model. Stephen Wolfram in his book entitled “A New Kind of Science” discusses the formation rules based on the statistical analysis. In accordance with Stephen Wolfram’s investigation, the research will develop a basic idea of computer program using Delphi 7 programming language. To best of our knowledge, there is no previous research developing a simulation describing root forms using the cellular automata model compared to the natural root form with the presence of stone addition as the disturbance. The result shows that (1) the simulation used four rules comparing results of the program towards the natural photographs and each rule had shown different root forms; (2) the stone disturbances prevent the root growth and the multiplication of root forms had been successfully modeled. Therefore, this research had added some stones, which have size of 120 cells placed randomly in the soil. Like in nature, stones cannot be penetrated by plant roots. The result showed that it is very likely to further develop the program of simulating root forms by 50 variations.
Simulation of root forms using cellular automata model
NASA Astrophysics Data System (ADS)
Winarno, Nanang; Prima, Eka Cahya; Afifah, Ratih Mega Ayu
2016-02-01
This research aims to produce a simulation program for root forms using cellular automata model. Stephen Wolfram in his book entitled "A New Kind of Science" discusses the formation rules based on the statistical analysis. In accordance with Stephen Wolfram's investigation, the research will develop a basic idea of computer program using Delphi 7 programming language. To best of our knowledge, there is no previous research developing a simulation describing root forms using the cellular automata model compared to the natural root form with the presence of stone addition as the disturbance. The result shows that (1) the simulation used four rules comparing results of the program towards the natural photographs and each rule had shown different root forms; (2) the stone disturbances prevent the root growth and the multiplication of root forms had been successfully modeled. Therefore, this research had added some stones, which have size of 120 cells placed randomly in the soil. Like in nature, stones cannot be penetrated by plant roots. The result showed that it is very likely to further develop the program of simulating root forms by 50 variations.
Viscous and thermal modelling of thermoplastic composites forming process
NASA Astrophysics Data System (ADS)
Guzman, Eduardo; Liang, Biao; Hamila, Nahiene; Boisse, Philippe
2016-10-01
Thermoforming thermoplastic prepregs is a fast manufacturing process. It is suitable for automotive composite parts manufacturing. The simulation of thermoplastic prepreg forming is achieved by alternate thermal and mechanical analyses. The thermal properties are obtained from a mesoscopic analysis and a homogenization procedure. The forming simulation is based on a viscous-hyperelastic approach. The thermal simulations define the coefficients of the mechanical model that depend on the temperature. The forming simulations modify the boundary conditions and the internal geometry of the thermal analyses. The comparison of the simulation with an experimental thermoforming of a part representative of automotive applications shows the efficiency of the approach.
Evaluating College Campus Closings for the 1980s: A Case Application of an Optimization Model.
ERIC Educational Resources Information Center
Hoenack, Stephen A.; Roemer, Janet K.
1981-01-01
Using estimated enrollment demand functions and readily available data on size, quality, and costs, a model, designed to assist policy-makers in identifying overbuilt institutions and programs that should be closed is described. This study is a case application of an optimatization model to two community colleges in northern Minnesota. (Author/MLW)
Modeling and control of a LN2-GN2 operated closed circuit cryogenic wind tunnel
NASA Technical Reports Server (NTRS)
Balakrishna, S.; Thibodeaux, J. J.
1979-01-01
An explicit but simple lumped parameter nonlinear multivariable model of a LN2-GN2-operated closed circuit cryogenic wind tunnel has been developed and its basic features have been experimentally validated. The model describes the mass-energy interaction involved in the cryogenic tunnel process and includes the real gas properties of nitrogen gas.
Numerical Modelling of Drawbeads for Forming of Aluminium Alloys
NASA Astrophysics Data System (ADS)
Joshi, Y.; Christiansen, P.; Masters, I.; Bay, N.; Dashwood, R.
2016-08-01
The drawbeads in stamping tools are usually designed based on experience from the forming of steel. However, aluminium alloys display different forming behaviour to steels, which is not reflected in the drawbead design for tools used for stamping aluminium. This paper presents experimental results from different semi-circular drawbead geometries commonly encountered in automotive dies and compares them to those obtained from Stoughton's analytical drawbead model and the 2D plane strain drawbead model set up using LS-DYNA. The study was conducted on lubricated NG5754 strips. The results presented are in terms of drawbead restraining force versus strip displacement, as a function of drawbead depth. The FE drawbead model agrees well with the experiments whereas the analytical model overpredicted the drawbead forces.
Hippocampal Closed-Loop Modeling and Implications for Seizure Stimulation Design
Sandler, Roman A.; Song, Dong; Hampson, Robert E.; Deadwyler, Sam A.; Berger, Theodore W.; Marmarelis, Vasilis Z.
2016-01-01
Objective Traditional hippocampal modeling has focused on the series of feedforward synapses known as the trisynaptic pathway. However, feedback connections from CA1 back to the hippocampus through the Entorhinal Cortex (EC) actually make the hippocampus a closed-loop system. By constructing a functional closed-loop model of the hippocampus, one may learn how both physiological and epileptic oscillations emerge and design efficient neurostimulation patterns to abate such oscillations. Approach Point process input-output models where estimated from recorded rodent hippocampal data to describe the nonlinear dynamical transformation from CA3→CA1, via the Schaffer-Collateral synapse, and CA1→CA3 via the EC. Each Volterra-like subsystem was composed of linear dynamics (Principal Dynamic Modes) followed by static nonlinearities. The two subsystems were then wired together to produce the full closed-loop model of the hippocampus. Main Results Closed-loop connectivity was found to be necessary for the emergence of theta resonances as seen in recorded data, thus validating the model. The model was then used to identify frequency parameters for the design of neurostimulation patterns to abate seizures. Significance DBS is a new and promising therapy for intractable seizures. Currently, there is no efficient way to determine optimal frequency parameters for DBS, or even whether periodic or broadband stimuli are optimal. Data-based computational models have the potential to be used as a testbed for designing optimal DBS patterns for individual patients. However, in order for these models to be successful they must incorporate the complex closed-loop structure of the seizure focus. This study serves as a proof-of-concept of using such models to design efficient personalized DBS patterns for epilepsy. PMID:26355815
Hippocampal closed-loop modeling and implications for seizure stimulation design
NASA Astrophysics Data System (ADS)
Sandler, Roman A.; Song, Dong; Hampson, Robert E.; Deadwyler, Sam A.; Berger, Theodore W.; Marmarelis, Vasilis Z.
2015-10-01
Objective. Traditional hippocampal modeling has focused on the series of feedforward synapses known as the trisynaptic pathway. However, feedback connections from CA1 back to the hippocampus through the entorhinal cortex (EC) actually make the hippocampus a closed-loop system. By constructing a functional closed-loop model of the hippocampus, one may learn how both physiological and epileptic oscillations emerge and design efficient neurostimulation patterns to abate such oscillations. Approach. Point process input-output models where estimated from recorded rodent hippocampal data to describe the nonlinear dynamical transformation from CA3 → CA1, via the schaffer-collateral synapse, and CA1 → CA3 via the EC. Each Volterra-like subsystem was composed of linear dynamics (principal dynamic modes) followed by static nonlinearities. The two subsystems were then wired together to produce the full closed-loop model of the hippocampus. Main results. Closed-loop connectivity was found to be necessary for the emergence of theta resonances as seen in recorded data, thus validating the model. The model was then used to identify frequency parameters for the design of neurostimulation patterns to abate seizures. Significance. Deep-brain stimulation (DBS) is a new and promising therapy for intractable seizures. Currently, there is no efficient way to determine optimal frequency parameters for DBS, or even whether periodic or broadband stimuli are optimal. Data-based computational models have the potential to be used as a testbed for designing optimal DBS patterns for individual patients. However, in order for these models to be successful they must incorporate the complex closed-loop structure of the seizure focus. This study serves as a proof-of-concept of using such models to design efficient personalized DBS patterns for epilepsy.
Challenges in Modeling the Degradation of Ceramic Waste Forms
Devanathan, Ramaswami; Gao, Fei; Sun, Xin
2011-09-01
We identify the state of the art, gaps in current understanding, and key research needs in the area of modeling the long-term degradation of ceramic waste forms for nuclear waste disposition. The directed purpose of this report is to define a roadmap for Waste IPSC needs to extend capabilities of waste degradation to ceramic waste forms, which overlaps with the needs of the subconsinuum scale of FMM interests. The key knowledge gaps are in the areas of (i) methodology for developing reliable interatomic potentials to model the complex atomic-level interactions in waste forms; (ii) characterization of water interactions at ceramic surfaces and interfaces; and (iii) extension of atomic-level insights to the long time and distance scales relevant to the problem of actinide and fission product immobilization.
17 CFR Appendix to Subpart B of... - Model Forms
Code of Federal Regulations, 2010 CFR
2010-04-01
... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Model Forms Appendix to Subpart B of Part 248 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED... “credit card,” “insurance,” or “securities” affiliates. 5. Omitting items that are not accurate...
Star-forming galaxy models: Blending star formation into TREESPH
NASA Technical Reports Server (NTRS)
Mihos, J. Christopher; Hernquist, Lars
1994-01-01
We have incorporated star-formation algorithms into a hybrid N-body/smoothed particle hydrodynamics code (TREESPH) in order to describe the star forming properties of disk galaxies over timescales of a few billion years. The models employ a Schmidt law of index n approximately 1.5 to calculate star-formation rates, and explicitly include the energy and metallicity feedback into the Interstellar Medium (ISM). Modeling the newly formed stellar population is achieved through the use of hybrid SPH/young star particles which gradually convert from gaseous to collisionless particles, avoiding the computational difficulties involved in creating new particles. The models are shown to reproduce well the star-forming properties of disk galaxies, such as the morphology, rate of star formation, and evolution of the global star-formation rate and disk gas content. As an example of the technique, we model an encounter between a disk galaxy and a small companion which gives rise to a ring galaxy reminiscent of the Cartwheel (AM 0035-35). The primary galaxy in this encounter experiences two phases of star forming activity: an initial period during the expansion of the ring, and a delayed phase as shocked material in the ring falls back into the central regions.
12 CFR Appendix A to Part 216 - Model Privacy Form
Code of Federal Regulations, 2010 CFR
2010-01-01
... common privacy notice, to meet the content requirements of the privacy notice and opt-out notice set... layout, content, format, style, pagination, and shading. Institutions seeking to obtain the safe harbor... the word “member” whenever it appears in the model form, as appropriate. 2. The Contents of the...
12 CFR Appendix A to Part 332 - Model Privacy Form
Code of Federal Regulations, 2010 CFR
2010-01-01
... common privacy notice, to meet the content requirements of the privacy notice and opt-out notice set... layout, content, format, style, pagination, and shading. Institutions seeking to obtain the safe harbor... the word “member” whenever it appears in the model form, as appropriate. 2. The Contents of the...
Why Do Some Estuaries Close: A Model of Estuary Entrance Morphodynamics.
NASA Astrophysics Data System (ADS)
McSweeney, S. L.; Kennedy, D. M.; Rutherfurd, I.
2014-12-01
Intermittently Closed/Open Coastal Lakes/Lagoons (ICOLLs) are a form of wave-dominated, microtidal estuary that experience periodic closure in times of low river flow. ICOLL entrance morphodynamics are complex due to the interaction between wave, tidal and fluvial processes. Managers invest substantial funds to artificially open ICOLLs as they flood surrounding property and infrastructure, and have poor water quality. Existing studies examine broad scale processes but do not identify the main drivers of entrance condition. In this research, the changes in entrance geomorphology were surveyed before and after artificial entrance openings in three ICOLLs in Victoria, Australia. Changes in morphology were related to continuous measures of sediment volume, water level, tide and wave energy. A six-stage quantitative phase model of entrance geomorphology and hydrodynamics is presented to illustrate the spatio-temporal variability in ICOLL entrance morphodynamics. Phases include: breakout; channel expansion with rapid outflow; open with tidal exchange; initial berm rebuilding with tidal attenuation; partial berm recovery with rising water levels; closed with perched water levels. Entrance breakout initiates incision of a pilot channel to the ocean, whereby basin water levels then decline and channel expansion as the headcut migrates landwards. Peak outflow velocities of 5 m/s-3 were recorded and channel dimensions increased over 6 hrs to 3.5 m deep and 140 m wide. When tidal, a clear semi-diurnal signal is superimposed upon an otherwise stable water level. Deep-water wave energy was transferred 1.8 km upstream of the rivermouth with bores present in the basin. Berm rebuilding occurred by littoral drift and cross-shore transport once outflow ceased and microscale bedform features, particularly antidunes, contributed to sediment progradation. Phase duration is dependant on how high the estuary was perched above mean sea level, tidal prism extent, and onshore sediment supply
NASA Astrophysics Data System (ADS)
Blanloeuil, P.; Meziane, A.
2015-10-01
The non-collinear mixing technique is applied for detection and characterization of closed cracks. The method is based on the nonlinear interaction of two shear waves generated with an oblique incidence. This interaction leads to the scattering of a longitudinal wave. A Finite Element model is used to demonstrate its application to a closed crack. Contact acoustic nonlinearity is the nonlinear effect considered here and is modeled using unilateral contact law with Coulomb's friction. Directivity patterns are computed using a two-step procedure. The Finite Element (FE) model provides the near-field solution on a circular boundary surrounding the closed crack. The solution in the far-field is then determined assuming that the material has a linear behavior. Directivity patterns will be used to analyze the direction of propagation of longitudinal wave(s) scattered from the closed crack. Numerical results show that the method is effective and promising when applied to a closed crack. Scattering of the longitudinal wave also enables us to image the crack, giving position and size indications. Finally, the method offers the possibility to distinguish classical nonlinearity from contact acoustic nonlinearity.
Pole-zero form fractional model identification in frequency domain
Mansouri, R.; Djamah, T.; Djennoune, S.; Bettayeb, M.
2009-03-05
This paper deals with system identification in the frequency domain using non integer order models given in the pole-zero form. The usual identification techniques cannot be used in this case because of the non integer orders of differentiation which makes the problem strongly nonlinear. A general identification method based on Levenberg-Marquardt algorithm is developed and allows to estimate the (2n+2m+1) parameters of the model. Its application to identify the ''skin effect'' of a squirrel cage induction machine modeling is then presented.
Status of ceramic waste form degradation and radionuclide release modeling.
Fanning, T. H.; Ebert, W. L.; Frank, S. M.; Hash, M. C.; Morris, E. E.; Morss, L. R.; O'Holleran, T. P.; Wigeland, R. A.
2003-02-26
As part of the spent fuel treatment program at Argonne National Laboratory (ANL), a ceramic waste form is being developed for disposition of the salt waste stream generated during the treatment process. Ceramic waste form (CWF) degradation and radionuclide release modeling is being carried out for the purpose of estimating the impact of the CWF on the performance of the proposed repository at Yucca Mountain. The CWF is composed of approximately 75 wt% salt-loaded sodalite encapsulated in 25 wt% glass binder. Most radionuclides are present as small inclusion phases in the glass. Since the release of radionuclides can only occur as the glass and sodalite phases dissolve, the dissolution rates of the glass and sodalite phases are modeled to provide an upper bound to radionuclide release rates from the CWF. Transition-state theory for the dissolution of aluminosilicate minerals provides a mechanistic basis for the CWF degradation model, while model parameters are obtained by experimental measurements. Performance assessment calculations are carried out using the engineered barrier system model from the Total System Performance Assessment--Viability Assessment (TSPA-VA) for the proposed repository at Yucca Mountain. The analysis presented herein suggests that the CWF will perform in the repository environment in a manner that is similar to other waste forms destined for the repository.
Degradation modeling of the ANL ceramic waste form
Fanning, T. H.; Morss, L. R.
2000-03-28
A ceramic waste form composed of glass-bonded sodalite is being developed at Argonne National Laboratory (ANL) for immobilization and disposition of the molten salt waste stream from the electrometallurgical treatment process for metallic DOE spent nuclear fuel. As part of the spent fuel treatment program at ANL, a model is being developed to predict the long-term release of radionuclides under repository conditions. Dissolution tests using dilute, pH-buffered solutions have been conducted at 40, 70, and 90 C to determine the temperature and pH dependence of the dissolution rate. Parameter values measured in these tests have been incorporated into the model, and preliminary repository performance assessment modeling has been completed. Results indicate that the ceramic waste form should be acceptable in a repository environment.
Breather solutions for inhomogeneous FPU models using Birkhoff normal forms
NASA Astrophysics Data System (ADS)
Martínez-Farías, Francisco; Panayotaros, Panayotis
2016-11-01
We present results on spatially localized oscillations in some inhomogeneous nonlinear lattices of Fermi-Pasta-Ulam (FPU) type derived from phenomenological nonlinear elastic network models proposed to study localized protein vibrations. The main feature of the FPU lattices we consider is that the number of interacting neighbors varies from site to site, and we see numerically that this spatial inhomogeneity leads to spatially localized normal modes in the linearized problem. This property is seen in 1-D models, and in a 3-D model with a geometry obtained from protein data. The spectral analysis of these examples suggests some non-resonance assumptions that we use to show the existence of invariant subspaces of spatially localized solutions in quartic Birkhoff normal forms of the FPU systems. The invariant subspaces have an additional symmetry and this fact allows us to compute periodic orbits of the quartic normal form in a relatively simple way.
Birn, J.; Hones, E.W. Jr. ); Craven, J.D.; Frank, L.A. ); Elphinstone, R.D. ); Stern, D.P. )
1991-03-01
Using the empirical Tsyganenko (1987) long model as a prime example of a megnetospheric field model, the authors have attempted to identify the boundary between open and closed field lines. They define as closed all field lines that are connested with the Earth at both ends and cross the equatorial plane earthward of x = {minus}70 R{sub E}, the tailward validity limit of the Tsyganenko model. They find that the form of the open/closed boundary at the Earth's surface, identified with the polar cap boundary, can exhibit the arrowhead shape, pointed toward the Sun, observed in horse collar auroras (Hones et al., 1989). The polar cap size in the Tsyganenko model increases with increasing K{sub p} values, and it becomes rounder and less pointed. The superposition of a net B{sub y} field, which is the expected consequence of an IMF B{sub y}, rotates the polar cap pattern and, for larger values, degrades the arrowhead shape, resulting in polar cap configurations consistent with known asymmetries in the aurora. The pointedness of the polar cap shape also diminishes or even completely disappears if the low-latitude magnetopause is assumed open and located considerably inside of the outermost magnetic flux surface in the Tsyganenko model. The arrowhead shape of the polar cap is found to be associated with a strong increase of B{sub z} from midnight toward the tail flanks, which is observed independently, and is possibly related to the NBZ field-aligned current system, observed during quiet times and strongly northward IMF B{sub z}. The larger B{sub z} values near the flanks of the tail cause more magnetic flux to close through these regions than through the midnight equatorial region.
A dimensionally-heterogeneous closed-loop model for the cardiovascular system and its applications.
Blanco, P J; Feijóo, R A
2013-05-01
In the present work a computational model of the entire cardiovascular system is developed using heterogeneous mathematical representations. This model integrates different levels of detail for the blood circulation. The arterial tree is described by a one dimensional model in order to simulate the wave propagation phenomena that take place at the larger arterial vessels. The inflow and outflow locations of this 1D model are coupled with lumped parameter descriptions of the remainder part of the circulatory system, closing the loop. The four cardiac valves are considered using a valve model which allows for stenoses and regurgitation phenomena. In addition, full 3D geometrical models of arterial districts are embedded in this closed-loop circuit to model the local blood flow in specific vessels. This kind of detailed closed-loop network for the cardiovascular system allows hemodynamics analyses of patient-specific arterial district, delivering naturally the appropriate boundary conditions for different cardiovascular scenarios. An example of application involving the effect of aortic insufficiency on the local hemodynamics of a cerebral aneurism is provided as a motivation to reproduce, through numerical simulation, the hemodynamic environment in patients suffering from infective endocarditis and mycotic aneurisms. The need for incorporating homeostatic control mechanisms is also discussed in view of the large sensitivity observed in the results, noting that this kind of integrative modeling allows such incorporation.
Detailed modeling of cluster galaxies in free-form lenses
NASA Astrophysics Data System (ADS)
Lam, Daniel
2015-08-01
The main goal of the Frontier Fields is to characterize the population of high redshift galaxies that are gravitationally lensed and magnified by foreground massive galaxy clusters. The magnification received by lensed images has to be accurately quantified in order to derive the correct science results. The magnification is in turn computed from lens models, which are constructed from various constraints, most commonly the positions and redshifts of multiply-lensed galaxies.The locations and magnification of multiple images that appear near cluster galaxies are very sensitive to the mass distribution of those individual galaxies. In current free-form lens models, they are at best crudely approximated by arbitrary mass halos and are usually being completely neglected. Given sufficient free parameters and iterations, such models may be highly consistent but their predictive power would be rather limited. This shortcoming is particularly pronounced in light of the recent discovery of the first multiply-lensed supernova in the Frontier Fields cluster MACSJ1149. The proximity of its images to cluster galaxies mandates detailed modeling on galaxy-scales, where free-form methods solely based on grid solutions simply fail.We present a hybrid free-form lens model of Abell 2744, which for the first time incorporates a detailed mass component modeled by GALFIT that accurately captures the stellar light distribution of the hundred brightest cluster galaxies. The model better reproduces the image positions than a previous version, which modeled cluster galaxies with simplistic NFW halos. Curiously, this improvement is found in all but system 2, which has two radial images appearing around the BCG. Despite its complex light profile is being captured by GALFIT, the persistent discrepancies suggest considering mass distributions that may be largely offset from the stellar light distribution.
Towards Industrial Application of Damage Models for Sheet Metal Forming
NASA Astrophysics Data System (ADS)
Doig, M.; Roll, K.
2011-05-01
Due to global warming and financial situation the demand to reduce the CO2-emission and the production costs leads to the permanent development of new materials. In the automotive industry the occupant safety is an additional condition. Bringing these arguments together the preferable approach for lightweight design of car components, especially for body-in-white, is the use of modern steels. Such steel grades, also called advanced high strength steels (AHSS), exhibit a high strength as well as a high formability. Not only their material behavior but also the damage behavior of AHSS is different compared to the performances of standard steels. Conventional methods for the damage prediction in the industry like the forming limit curve (FLC) are not reliable for AHSS. Physically based damage models are often used in crash and bulk forming simulations. The still open question is the industrial application of these models for sheet metal forming. This paper evaluates the Gurson-Tvergaard-Needleman (GTN) model and the model of Lemaitre within commercial codes with a goal of industrial application.
Existence of standard models of conic fibrations over non-algebraically-closed fields
Avilov, A A
2014-12-31
We prove an analogue of Sarkisov's theorem on the existence of a standard model of a conic fibration over an algebraically closed field of characteristic different from two for three-dimensional conic fibrations over an arbitrary field of characteristic zero with an action of a finite group. Bibliography: 16 titles.
Couple Infertility: From the Perspective of the Close-Relationship Model.
ERIC Educational Resources Information Center
Higgins, Barbara S.
1990-01-01
Presents Close-Relationship Model as comprehensive framework in which to examine interrelated nature of causes and effects of infertility on marital relationship. Includes these factors: physical and psychological characteristics of both partners; joint, couple characteristics; physical and social environment; and relationship itself. Discusses…
A Tissue Propagation Model for Validating Close-Proximity Biomedical Radiometer Measurements
NASA Technical Reports Server (NTRS)
Bonds, Q.; Herzig, P.; Weller, T.
2016-01-01
The propagation of thermally-generated electromagnetic emissions through stratified human tissue is studied herein using a non-coherent mathematical model. The model is developed to complement subsurface body temperature measurements performed using a close proximity microwave radiometer. The model takes into account losses and reflections as thermal emissions propagate through the body, before being emitted at the skin surface. The derivation is presented in four stages and applied to the human core phantom, a physical representation of a stomach volume of skin, muscle, and blood-fatty tissue. A drop in core body temperature is simulated via the human core phantom and the response of the propagation model is correlated to the radiometric measurement. The results are comparable, with differences on the order of 1.5 - 3%. Hence the plausibility of core body temperature extraction via close proximity radiometry is demonstrated, given that the electromagnetic characteristics of the stratified tissue layers are known.
Model-Driven Safety Analysis of Closed-Loop Medical Systems.
Pajic, Miroslav; Mangharam, Rahul; Sokolsky, Oleg; Arney, David; Goldman, Julian; Lee, Insup
2012-10-26
In modern hospitals, patients are treated using a wide array of medical devices that are increasingly interacting with each other over the network, thus offering a perfect example of a cyber-physical system. We study the safety of a medical device system for the physiologic closed-loop control of drug infusion. The main contribution of the paper is the verification approach for the safety properties of closed-loop medical device systems. We demonstrate, using a case study, that the approach can be applied to a system of clinical importance. Our method combines simulation-based analysis of a detailed model of the system that contains continuous patient dynamics with model checking of a more abstract timed automata model. We show that the relationship between the two models preserves the crucial aspect of the timing behavior that ensures the conservativeness of the safety analysis. We also describe system design that can provide open-loop safety under network failure.
Wang, Junsong; Niebur, Ernst; Hu, Jinyu; Li, Xiaoli
2016-01-01
Closed-loop control is a promising deep brain stimulation (DBS) strategy that could be used to suppress high-amplitude epileptic activity. However, there are currently no analytical approaches to determine the stimulation parameters for effective and safe treatment protocols. Proportional-integral (PI) control is the most extensively used closed-loop control scheme in the field of control engineering because of its simple implementation and perfect performance. In this study, we took Jansen’s neural mass model (NMM) as a test bed to develop a PI-type closed-loop controller for suppressing epileptic activity. A graphical stability analysis method was employed to determine the stabilizing region of the PI controller in the control parameter space, which provided a theoretical guideline for the choice of the PI control parameters. Furthermore, we established the relationship between the parameters of the PI controller and the parameters of the NMM in the form of a stabilizing region, which provided insights into the mechanisms that may suppress epileptic activity in the NMM. The simulation results demonstrated the validity and effectiveness of the proposed closed-loop PI control scheme. PMID:27273563
NASA Astrophysics Data System (ADS)
Wang, Junsong; Niebur, Ernst; Hu, Jinyu; Li, Xiaoli
2016-06-01
Closed-loop control is a promising deep brain stimulation (DBS) strategy that could be used to suppress high-amplitude epileptic activity. However, there are currently no analytical approaches to determine the stimulation parameters for effective and safe treatment protocols. Proportional-integral (PI) control is the most extensively used closed-loop control scheme in the field of control engineering because of its simple implementation and perfect performance. In this study, we took Jansen’s neural mass model (NMM) as a test bed to develop a PI-type closed-loop controller for suppressing epileptic activity. A graphical stability analysis method was employed to determine the stabilizing region of the PI controller in the control parameter space, which provided a theoretical guideline for the choice of the PI control parameters. Furthermore, we established the relationship between the parameters of the PI controller and the parameters of the NMM in the form of a stabilizing region, which provided insights into the mechanisms that may suppress epileptic activity in the NMM. The simulation results demonstrated the validity and effectiveness of the proposed closed-loop PI control scheme.
Wang, Junsong; Niebur, Ernst; Hu, Jinyu; Li, Xiaoli
2016-06-07
Closed-loop control is a promising deep brain stimulation (DBS) strategy that could be used to suppress high-amplitude epileptic activity. However, there are currently no analytical approaches to determine the stimulation parameters for effective and safe treatment protocols. Proportional-integral (PI) control is the most extensively used closed-loop control scheme in the field of control engineering because of its simple implementation and perfect performance. In this study, we took Jansen's neural mass model (NMM) as a test bed to develop a PI-type closed-loop controller for suppressing epileptic activity. A graphical stability analysis method was employed to determine the stabilizing region of the PI controller in the control parameter space, which provided a theoretical guideline for the choice of the PI control parameters. Furthermore, we established the relationship between the parameters of the PI controller and the parameters of the NMM in the form of a stabilizing region, which provided insights into the mechanisms that may suppress epileptic activity in the NMM. The simulation results demonstrated the validity and effectiveness of the proposed closed-loop PI control scheme.
Li, Ping; Yang, Li; Ma, Cui-Li; Liu, Bo; Zhang, Xin; Ding, Rui; Bi, Li-qi
2015-06-01
Adiponectin is divided into high-molecular-weight (HMW), medium-molecular-weight (MMW), and low-molecular-weight (LMW) forms. These forms differ not only in the number of adiponectin molecules but also in their biological activity. There are conflicting findings regarding the role of adiponectin in rheumatoid arthritis (RA). Moreover, few reports have described the relationships between serum adiponectin multimers levels and RA. Therefore, we examined the association of total adiponectin and its multimers with RA. Two study groups were examined: 180 recently diagnosed untreated RA patients with disease duration less than 1 year (RA group) and 160 age- and sex-matched control subjects (control group). RA-related factors, blood pressure, body mass index, glucose, complete lipid profile, and adiponectin multimers were measured. The levels of total adiponectin and each multimer of adiponectin were significantly lower in the RA than in the control (P < 0.01). Serum levels of total, HMW, MMW, and LMW were positively correlated with triglycerides levels and negatively correlated with the Disease Activity Score for 28 joints (DAS28). Multivariate regression analysis showed that total, HMW, and MMW adiponectin were independently associated with serum triglycerides level. LMW adiponectin was independently correlated with serum triglycerides level and DAS28. The decreased LMW adiponectin levels may be associated with disease activity of RA.
Bernard, J.A. . Nuclear Reactor Lab.)
1989-09-01
This report describes both the theoretical development and the experimental evaluation of a novel, robust methodology for the time-optimal adjustment of a reactor's neutronic power under conditions of closed-loop digital control. Central to the approach are the MIT-SNL Period-Generated Minimum Time Control Laws' which determine the rate at which reactivity should be changed in order to cause a reactor's neutronic power to conform to a specified trajectory. Using these laws, reactor power can be safely raised by five to seven orders of magnitude in a few seconds. The MIT-SNL laws were developed to facilitate rapid increases of neutronic power on spacecraft reactors operating in an SDI environment. However, these laws are generic and have other applications including the rapid recovery of research and test reactors subsequent to an unanticipated shutdown, power increases following the achievement of criticality on commercial reactors, power adjustments on commercial reactors so as to minimize thermal stress, and automated startups. The work reported here was performed by the Massachusetts Institute of Technology under contract to the Sandia National Laboratories. Support was also provided by the US Department of Energy's Division of University and Industry Programs. The work described in this report is significant in that a novel solution to the problem of time-optimal control of neutronic power was identified, in that a rigorous description of a reactor's dynamics was derived in that the rate of change of reactivity was recognized as the proper control signal, and in that extensive experimental trials were conducted of these newly developed concepts on actual nuclear reactors. 43 refs., 118 figs., 11 tabs.
Octet Baryon Electromagnetic Form Factors in a Relativistic Quark Model
Gilberto Ramalho, Kazuo Tsushima
2011-09-01
We study the octet baryon electromagnetic properties by applying the covariant spectator quark model, and provide covariant parametrization that can be used to study baryon electromagnetic reactions. While we use the lattice QCD data in the large pion mass regime (small pion cloud effects) to determine the parameters of the model in the valence quark sector, we use the nucleon physical and octet baryon magnetic moment data to parameterize the pion cloud contributions. The valence quark contributions for the octet baryon electromagnetic form factors are estimated by extrapolating the lattice parametrization in the large pion mass regime to the physical regime. As for the pion cloud contributions, we parameterize them in a covariant, phenomenological manner, combined with SU(3) symmetry. We also discuss the impact of the pion cloud effects on the octet baryon electromagnetic form factors and their radii.
NASA Astrophysics Data System (ADS)
Suman, S.; Kumar, A.; Singh, G. K.
2015-04-01
In this paper, a new method for the design of variable bandwidth linear-phase finite impulse response filters using Bernstein polynomial Multiwavelets is proposed. In this method, approximation has been achieved by linearly combining the fixed coefficient linear phase filters with Bernstein multiwavelets, which are used to tune bandwidth of the filter. Optimisation has been achieved by minimising the mean square error between the desired and actual filter response which leads to a system of linear equations. The matrix elements can be expressed in form of Toeplitz-plus-Hankel matrix, which reduces the computational complexity. The simulation results illustrate significant improvement in errors in passband (ep), and stopband (es) as compared to earlier published work.
Models of Anisotropic Creep in Integral Wing Panel Forming Processes
NASA Astrophysics Data System (ADS)
Oleinikov, A. I.; Oleinikov, A. A.
2016-08-01
For a sufficiently wide range of stresses the titanic and aluminummagnesium alloys, as a rule, strained differently in the process of creep under tension and compression along a fixed direction. There are suggested constitutive relations for the description of the steady-state creep of transversely isotropic materials with different tension and compression characteristics. Experimental justification is given to the proposed constitutive equations. Modeling of forming of wing panels of the aircraft are considered.
Performance and Mass Modeling Subtleties in Closed-Brayton-Cycle Space Power Systems
NASA Technical Reports Server (NTRS)
Barrett, Michael J.; Johnson, Paul K.
2006-01-01
A number of potential NASA missions could benefit from closed-Brayton-cycle (CBC) power conversion systems. The human and robotic mission power applications include spacecraft, surface base, and rover scenarios. Modeling of CBC subsystems allows system engineers, mission planners and project managers to make informed decisions regarding power conversion system characteristics and capabilities. To promote thorough modeling efforts, a critical review of CBC modeling techniques is presented. Analysis of critical modeling elements, component influences and cycle sensitivities is conducted. The analysis leads to quantitative results addressing projections on converter efficiency and overall power conversion system mass. Even moderate modeling errors are shown to easily over-predict converter efficiencies by 30% and underestimate mass estimates by 20%. Both static and dynamic modeling regimes are evaluated. Key considerations in determining model fidelity requirements are discussed. Conclusions and recommendations are presented that directly address ongoing modeling efforts in solar and nuclear space power systems.
Performance and Mass Modeling Subtleties in Closed-Brayton-Cycle Space Power Systems
NASA Technical Reports Server (NTRS)
Barrett, Michael J.; Johnson, Paul K.
2005-01-01
A number of potential NASA missions could benefit from closed-Brayton-cycle (CBC) power conversion systems. The human and robotic mission power applications include spacecraft, surface base, and rover scenarios. Modeling of CBC subsystems allows system engineers, mission planners and project managers to make informed decisions regarding power conversion system characteristics and capabilities. To promote thorough modeling efforts, a critical review of CBC modeling techniques is presented. Analysis of critical modeling elements, component influences and cycle sensitivities is conducted. The analysis leads to quantitative results addressing projections on converter efficiency and overall power conversion system mass. Even moderate modeling errors are shown to easily over-predict converter efficiencies by 30 percent and underestimate mass estimates by 20 percent. Both static and dynamic modeling regimes are evaluated. Key considerations in determining model fidelity requirements are discussed. Conclusions and recommendations are presented that directly address ongoing modeling efforts in solar and nuclear space power systems.
Topology Model of the Flow around a Submarine Hull Form
2015-12-01
end of the tail cone starts at approximately 76%L. The “X”-rudders located at approximately 86-91%L are the aft control surfaces. The present model ...Top view Side view L ψ Casing NACA−0015 Fin Hull surfaces control Aft y z xψ Nose Figure 1: A schematic diagram of the generic conventional hull form...which can affect the motion control , manoeuvring and signature of the submarine. The flow-topology model (e.g. Fig. 31) shows the presence of a pair
Material Characterization and Modeling for Industrial Sheet Forming Simulations
NASA Astrophysics Data System (ADS)
Mattiasson, Kjell; Sigvant, Mats
2004-06-01
In the present paper a project carried out at Volvo Cars Corp. and Chalmers University of Technology, with the purpose of improving material characterization and modeling for sheet forming simulation, is described. One of the primary targets has been to identify a material testing procedure, which is capable of providing effective stress-strain data at considerably larger strains than what can be achieved in a standard uniaxial tensile test. Another objective has been to advance from the common Hill '48 material model to a more flexible one, and, furthermore, to identify suitable test procedures for determining the parameters of such a model. A third objective has been to find practical examples, in which the importance of a careful material modeling can be clearly demonstrated.
Modeling and forecasting foreign exchange daily closing prices with normal inverse Gaussian
NASA Astrophysics Data System (ADS)
Teneng, Dean
2013-09-01
We fit the normal inverse Gaussian(NIG) distribution to foreign exchange closing prices using the open software package R and select best models by Käärik and Umbleja (2011) proposed strategy. We observe that daily closing prices (12/04/2008 - 07/08/2012) of CHF/JPY, AUD/JPY, GBP/JPY, NZD/USD, QAR/CHF, QAR/EUR, SAR/CHF, SAR/EUR, TND/CHF and TND/EUR are excellent fits while EGP/EUR and EUR/GBP are good fits with a Kolmogorov-Smirnov test p-value of 0.062 and 0.08 respectively. It was impossible to estimate normal inverse Gaussian parameters (by maximum likelihood; computational problem) for JPY/CHF but CHF/JPY was an excellent fit. Thus, while the stochastic properties of an exchange rate can be completely modeled with a probability distribution in one direction, it may be impossible the other way around. We also demonstrate that foreign exchange closing prices can be forecasted with the normal inverse Gaussian (NIG) Lévy process, both in cases where the daily closing prices can and cannot be modeled by NIG distribution.
Numerical modelling of closed-cell aluminium foam under dynamic loading
NASA Astrophysics Data System (ADS)
Hazell, Paul; Kader, M. A.; Islam, M. A.; Escobedo, J. P.; Saadatfar, M.
2015-06-01
Closed-cell aluminium foams are extensively used in aerospace and automobile industries. The understanding of their behaviour under impact loading conditions is extremely important since impact problems are directly related to design of these engineering structures. This research investigates the response of a closed-cell aluminium foam (CYMAT) subjected to dynamic loading using the finite element software ABAQUS/explicit. The aim of this research is to numerically investigate the material and structural properties of closed-cell aluminium foam under impact loading conditions with interest in shock propagation and its effects on cell wall deformation. A μ-CT based 3D foam geometry is developed to simulate the local cell collapse behaviours. A number of numerical techniques are applied for modelling the crush behaviour of aluminium foam to obtain the more accurate results. The simulation results are compared with experimental data. Comparison of the results shows a good correlation between the experimental results and numerical predictions.
Forehead, Hugh I; O'Kelly, Charles J
2013-02-01
The destruction of mass cultures of microalgae by biological contamination of culture medium is a pervasive and expensive problem, in industry and research. A mathematical model has been formulated that attempts to explain contaminant growth dynamics in closed photobioreactors (PBRs). The model simulates an initial growth phase without PBR dilution, followed by a production phase in which culture is intermittently removed. Contaminants can be introduced at any of these stages. The model shows how exponential growth from low initial inocula can lead to "explosive" growth in the population of contaminants, appearing days to weeks after inoculation. Principal influences are contaminant growth rate, PBR dilution rate, and the size of initial contaminant inoculum. Predictions corresponded closely with observed behavior of two contaminants, Uronema sp. and Neoparamoeba sp., found in operating PBRs. A simple, cheap and effective protocol was developed for short-term prediction of contamination in PBRs, using microscopy and archived samples.
NASA Astrophysics Data System (ADS)
Ranjan, Rajiv; Mallick, Ashis; Prasad, Dilip K.
2017-03-01
The performance characteristics and temperature field of conducting-convecting-radiating annular fin are investigated. The nonlinear variation of thermal conductivity, power law dependency of heat transfer coefficient, linear variation of surface emissivity, and heat generation with the temperature are considered in the analysis. A semi-analytical approach, homotopy perturbation method is employed to solve the nonlinear differential equation of heat transfer. The analysis is presented in non-dimensional form, and the effect of various non-dimensional thermal parameters such as conduction-convection parameter, conduction-radiation parameter, linear and nonlinear variable thermal conductivity parameter, emissivity parameter, heat generation number and variable heat generation parameter are studied. For the correctness of the present analytical solution, the results are compared with the results available in the literature. In addition to forward problem, an inverse approach namely differential evolution method is employed for estimating the unknown thermal parameters for a given temperature field. The temperature fields are reconstructed using the inverse parameters and found to be in good agreement with the forward solution.
A mouse model of weight-drop closed head injury: emphasis on cognitive and neurological deficiency
Khalin, Igor; Jamari, Nor Laili Azua; Razak, Nadiawati Bt Abdul; Hasain, Zubaidah Bt; Nor, Mohd Asri bin Mohd; Zainudin, Mohd Hakimi bin Ahmad; Omar, Ainsah Bt; Alyautdin, Renad
2016-01-01
Traumatic brain injury (TBI) is a leading cause of death and disability in individuals worldwide. Producing a clinically relevant TBI model in small-sized animals remains fairly challenging. For good screening of potential therapeutics, which are effective in the treatment of TBI, animal models of TBI should be established and standardized. In this study, we established mouse models of closed head injury using the Shohami weight-drop method with some modifications concerning cognitive deficiency assessment and provided a detailed description of the severe TBI animal model. We found that 250 g falling weight from 2 cm height produced severe closed head injury in C57BL/6 male mice. Cognitive disorders in mice with severe closed head injury could be detected using passive avoidance test on day 7 after injury. Findings from this study indicate that weight-drop injury animal models are suitable for further screening of brain neuroprotectants and potentially are similar to those seen in human TBI. PMID:27212925
Integrating Entropy and Closed Frequent Pattern Mining for Social Network Modelling and Analysis
NASA Astrophysics Data System (ADS)
Adnan, Muhaimenul; Alhajj, Reda; Rokne, Jon
The recent increase in the explicitly available social networks has attracted the attention of the research community to investigate how it would be possible to benefit from such a powerful model in producing effective solutions for problems in other domains where the social network is implicit; we argue that social networks do exist around us but the key issue is how to realize and analyze them. This chapter presents a novel approach for constructing a social network model by an integrated framework that first preparing the data to be analyzed and then applies entropy and frequent closed patterns mining for network construction. For a given problem, we first prepare the data by identifying items and transactions, which arc the basic ingredients for frequent closed patterns mining. Items arc main objects in the problem and a transaction is a set of items that could exist together at one time (e.g., items purchased in one visit to the supermarket). Transactions could be analyzed to discover frequent closed patterns using any of the well-known techniques. Frequent closed patterns have the advantage that they successfully grab the inherent information content of the dataset and is applicable to a broader set of domains. Entropies of the frequent closed patterns arc used to keep the dimensionality of the feature vectors to a reasonable size; it is a kind of feature reduction process. Finally, we analyze the dynamic behavior of the constructed social network. Experiments were conducted on a synthetic dataset and on the Enron corpus email dataset. The results presented in the chapter show that social networks extracted from a feature set as frequent closed patterns successfully carry the community structure information. Moreover, for the Enron email dataset, we present an analysis to dynamically indicate the deviations from each user's individual and community profile. These indications of deviations can be very useful to identify unusual events.
The Defect Diffusion Model of Glass-Forming Liquids
NASA Astrophysics Data System (ADS)
Fontanella, John; Bendler, John; Wintersgill, Mary; Shlesinger, Michael
2013-03-01
The defect diffusion model (DDM) provides an explanation of many properties of glass-forming liquids. For example, it has been used to interpret dielectric relaxation (alpha and beta relaxations and the boson peak), viscosity, ionic conductivity, (including the effects of temperature and pressure) positron annihilation lifetime spectroscopy data, the physical basis of fragility, scaling, the ratio of the apparent isochoric activation energy to the isobaric activation enthalpy and its relationship to monomer volume, and correlation lengths. In the model, the glass transition, Tg, occurs because of rigidity percolation. In addition the transition at TB (or TLL) is associated with mobility percolation. In the simplest form of the DDM, a supercooled liquid contains mobile single defects (MSDs) and immobile, clustered single defects (ICSDs). Consequently, dynamic heterogeneity is a natural feature of the model. If the glass transition did not intervene, all MSDs would disappear at a critical temperature Tc. In the present talk, the model will be used to comment on the change of heat capacity, thermal expansion coefficient and compressibility at Tg. Work supported in part by the Office of Naval Research
Electrochemical Corrosion Studies for Modeling Metallic Waste Form Release Rates
Poineau, Frederic; Tamalis, Dimitri
2016-08-01
The isotope ^{99}Tc is an important fission product generated from nuclear power production. Because of its long half-life (t_{1/2} = 2.13 ∙ 10^{5} years) and beta-radiotoxicity (β⁻ = 292 keV), it is a major concern in the long-term management of spent nuclear fuel. In the spent nuclear fuel, Tc is present as an alloy with Mo, Ru, Rh, and Pd called the epsilon-phase, the relative amount of which increases with fuel burn-up. In some separation schemes for spent nuclear fuel, Tc would be separated from the spent fuel and disposed of in a durable waste form. Technetium waste forms under consideration include metallic alloys, oxide ceramics and borosilicate glass. In the development of a metallic waste form, after separation from the spent fuel, Tc would be converted to the metal, incorporated into an alloy and the resulting waste form stored in a repository. Metallic alloys under consideration include Tc–Zr alloys, Tc–stainless steel alloys and Tc–Inconel alloys (Inconel is an alloy of Ni, Cr and iron which is resistant to corrosion). To predict the long-term behavior of the metallic Tc waste form, understanding the corrosion properties of Tc metal and Tc alloys in various chemical environments is needed, but efforts to model the behavior of Tc metallic alloys are limited. One parameter that should also be considered in predicting the long-term behavior of the Tc waste form is the ingrowth of stable Ru that occurs from the radioactive decay of ^{99}Tc (^{99}Tc → ^{99}Ru + β⁻). After a geological period of time, significant amounts of Ru will be present in the Tc and may affect its corrosion properties. Studying the effect of Ru on the corrosion behavior of Tc is also of importance. In this context, we studied the electrochemical behavior of Tc metal, Tc-Ni alloys (to model Tc-Inconel alloy) and Tc-Ru alloys in acidic media. The study of Tc-U alloys has also been performed in order to better understand the
Modelling stellar proton event-induced particle radiation dose on close-in exoplanets
NASA Astrophysics Data System (ADS)
Atri, Dimitra
2017-02-01
Kepler observations have uncovered the existence of a large number of close-in exoplanets and serendipitously of stellar superflares with emissions several orders of magnitude higher than those observed on the Sun. The interaction between the two and their implications on planetary habitability are of great interest to the community. Stellar proton events (SPEs) interact with planetary atmospheres, generate secondary particles and increase the radiation dose on the surface. This effect is amplified for close-in exoplanets and can be a serious threat to potential planetary life. Monte Carlo simulations are used to model the SPE-induced particle radiation dose on the surface of such exoplanets. The results show a wide range of surface radiation doses on planets in close-in configurations with varying atmospheric column depths, magnetic moments and orbital radii. It can be concluded that for close-in exoplanets with sizable atmospheres and magnetospheres, the radiation dose contributed by stellar superflares may not be high enough to sterilize a planet (for life as we know it) but can result in frequent extinction level events. In light of recent reports, the interaction of hard-spectrum SPEs with the atmosphere of Proxima Centauri b is modelled and their implications on its habitability are discussed.
Pao, H; Zhu, Z; Dvorak, S L
2004-01-28
The radio channel places fundamental limitations on the performance of wireless communication systems in tunnels and caves. The transmission path between the transmitter and receiver can vary from a simple direct line of sight to one that is severely obstructed by rough walls and corners. Unlike wired channels that are stationary and predictable, radio channels can be extremely random and difficult to analyze. In fact, modeling the radio channel has historically been one of the more challenging parts of any radio system design; this is often done using statistical methods. The mechanisms behind electromagnetic wave propagation are diverse, but can generally be attributed to reflection, diffraction, and scattering. Because of the multiple reflections from rough walls, the electromagnetic waves travel along different paths of varying lengths. The interactions between these waves cause multipath fading at any location, and the strengths of the waves decrease as the distance between the transmitter and receiver increases. As a consequence of the central limit theorem, the received signals are approximately Gaussian random process. This means that the field propagating in a cave or tunnel is typically a complex-valued Gaussian random process.
Turbulence model form uncertainty quantification in OpenFOAM
NASA Astrophysics Data System (ADS)
Hao, Zengrong; Zeoli, Stéphanie; Bricteux, Laurent; Gorlé, Catherine; CFD; UQ Team; Fluids-Machines Team
2015-11-01
Reynolds-averaged Navier-Stokes (RANS) simulations with a two-equation linear eddy-viscosity turbulence model remain a commonly used computational technique for engineering design and analysis of turbulent flows. The accuracy of the results is however limited by the inability of the turbulence model to correctly predict the complex flow features relevant to engineering applications. To enable supporting critical design decisions based on these imperfect model results it is essential to quantify the uncertainty related to the turbulence model form and define confidence levels for the results. The objective of this study is the implementation and validation of a previously developed approach for quantifying the uncertainty in RANS predictions of a turbulent flow in the open source code OpenFOAM. The methodology is based on two steps: 1. calculate a marker to determine where in the flow the model is plausibly inaccurate, and 2. perturb the modeled Reynolds stresses in the momentum equations. The perturbations are defined in terms of the decomposed Reynolds stress tensor, i.e., the tensor magnitude and the eigenvalues and eigenvectors of the normalized anisotropy tensor. Results for a square duct and the flow over a wavy wall will be presented for validation of the implementation.
Various forms of indexing HDMR for modelling multivariate classification problems
Aksu, Çağrı; Tunga, M. Alper
2014-12-10
The Indexing HDMR method was recently developed for modelling multivariate interpolation problems. The method uses the Plain HDMR philosophy in partitioning the given multivariate data set into less variate data sets and then constructing an analytical structure through these partitioned data sets to represent the given multidimensional problem. Indexing HDMR makes HDMR be applicable to classification problems having real world data. Mostly, we do not know all possible class values in the domain of the given problem, that is, we have a non-orthogonal data structure. However, Plain HDMR needs an orthogonal data structure in the given problem to be modelled. In this sense, the main idea of this work is to offer various forms of Indexing HDMR to successfully model these real life classification problems. To test these different forms, several well-known multivariate classification problems given in UCI Machine Learning Repository were used and it was observed that the accuracy results lie between 80% and 95% which are very satisfactory.
A comparison of closed- and open-system models for porewater pH and calcite-saturation state
NASA Astrophysics Data System (ADS)
Boudreau, Bernard P.; Canfield, Donald E.
1993-01-01
We compare the theoretical predictions of a closed- and an open-system model for the evolution of pH and calcite-saturation state during the sequential oxidation of organic matter by O 2, NO 3-, and SO 4=. The closed-system model is similar to previous thermodynamic models found in the geochemical literature (e.g., BEN-YAAKOV, 1973). The open-system model allows for differential diffusion of dissolved species, exchange with overlying waters, fast acid/base reactions, and a variety of spatially distributed sources and sinks. In particular, dissolution and precipitation of minerals are included either as local equilibrium processes as in the case of calcite dissolution, or as depth-dependent exponentials as for FeS and CaCO 3 precipitation. The model calculations reveal that closed and open systems have qualitatively similar behavior with respect to pH and carbonate saturation, Ω c. However, a quantitative comparison establishes that the closed-system model represents usually an upper limit on pH in the oxic zone of sediments, while it always sets a lower bound on pH in the zone of SO 4-- reduction. The changes in Ω c in closed and open systems during oxic decay are more complex than those of pH. The closed system will present an upper limit on Ω c when the initial pH is high (i.e., 8.0), but does not exhibit limiting behavior if the initial pH is low (i.e., 7.0). The closed-system model always places a lower limit on Ω c during sulfate reduction. Both models predict that CaCO 3 dissolution can buffer the potential pH fall due to oxic CO 2 production; however, quantitative evaluation of this effect requires a diagenetic model with realistic dissolution kinetics. Our investigations also demonstrate that vigorous mono-sulfide precipitation from an FeOOH-iron source can mitigate the fall in pH normally associated with organic matter decay as this mineral-forming reaction consumes an important protolytic species, H 2S. On the other hand, the precipitation of CaCO 3
Modeling Close-In Airblast from ANFO Cylindrical and Box-Shaped Charges
2010-10-01
ANFO ) were detonated at various heights above a heavy steel plate. The plate was instrumented with twelve PCB piezoelectric pressure sensors with a...MODELING CLOSE-IN AIRBLAST FROM ANFO CYLINDRICAL AND BOX-SHAPED CHARGES Bob Britt, Tyler Oesch, Bob Walker, Dave Hyde, and Will McMahon...pressures) through a series of experiments and numerical simulations. Cylindrical and box-shaped charges of ammonium nitrate with fuel oil ( ANFO ) were
NASA Astrophysics Data System (ADS)
Wang, Jun-Song; Wang, Mei-Li; Li, Xiao-Li; Ernst, Niebur
2015-03-01
Epilepsy is believed to be caused by a lack of balance between excitation and inhibitation in the brain. A promising strategy for the control of the disease is closed-loop brain stimulation. How to determine the stimulation control parameters for effective and safe treatment protocols remains, however, an unsolved question. To constrain the complex dynamics of the biological brain, we use a neural population model (NPM). We propose that a proportional-derivative (PD) type closed-loop control can successfully suppress epileptiform activities. First, we determine the stability of root loci, which reveals that the dynamical mechanism underlying epilepsy in the NPM is the loss of homeostatic control caused by the lack of balance between excitation and inhibition. Then, we design a PD type closed-loop controller to stabilize the unstable NPM such that the homeostatic equilibriums are maintained; we show that epileptiform activities are successfully suppressed. A graphical approach is employed to determine the stabilizing region of the PD controller in the parameter space, providing a theoretical guideline for the selection of the PD control parameters. Furthermore, we establish the relationship between the control parameters and the model parameters in the form of stabilizing regions to help understand the mechanism of suppressing epileptiform activities in the NPM. Simulations show that the PD-type closed-loop control strategy can effectively suppress epileptiform activities in the NPM. Project supported by the National Natural Science Foundation of China (Grant Nos. 61473208, 61025019, and 91132722), ONR MURI N000141010278, and NIH grant R01EY016281.
RANS turbulence model form uncertainty quantification for wind engineering flows
NASA Astrophysics Data System (ADS)
Gorle, Catherine; Zeoli, Stephanie; Bricteux, Laurent
2016-11-01
Reynolds-averaged Navier-Stokes simulations with linear eddy-viscosity turbulence models are commonly used for modeling wind engineering flows, but the use of the results for critical design decisions is hindered by the limited capability of the models to correctly predict bluff body flows. A turbulence model form uncertainty quantification (UQ) method to define confidence intervals for the results could remove this limitation, and promising results were obtained in a previous study of the flow in downtown Oklahoma City. The objective of the present study is to further investigate the validity of these results by considering the simplified test case of the flow around a wall-mounted cube. DNS data is used to determine: 1. whether the marker, which identifies regions that deviate from parallel shear flow, is a good indicator for the regions where the turbulence model fails, and 2. which Reynolds stress perturbations, in terms of the tensor magnitude and the eigenvalues and eigenvectors of the normalized anisotropy tensor, can capture the uncertainty in the flow field. A comparison of confidence intervals obtained with the UQ method and the DNS solution indicates that the uncertainty in the velocity field can be captured correctly in a large portion of the flow field.
SOYCHMBR.I - A model designed for the study of plant growth in a closed chamber
NASA Technical Reports Server (NTRS)
Reinhold, C.
1982-01-01
The analytical model SOYCHMBER.I, an update and alteration of the SOYMOD/OARDC model, for describing the total processes experienced by a plant in a controlled mass environment is outlined. The model is intended for use with growth chambers for examining plant growth in a completely controlled environment, leading toward a data base for the design of spacecraft food supply systems. SOYCHMBER.I accounts for the assimilation, respiration, and partitioning of photosynthate and nitrogen compounds among leaves, stems, roots, and potentially, flowers of the soybean plant. The derivation of the governing equations is traced, and the results of the prediction of CO2 dynamics for a seven day experiment with rice in a closed chamber are reported, together with data from three model runs for soybean. It is concluded that the model needs expansion to account for factors such as relative humidity.
Chevillotte, Fabien; Perrot, Camille; Panneton, Raymond
2010-10-01
Closed-cell metallic foams are known for their rigidity, lightness, thermal conductivity as well as their low production cost compared to open-cell metallic foams. However, they are also poor sound absorbers. Similarly to a rigid solid, a method to enhance their sound absorption is to perforate them. This method has shown good preliminary results but has not yet been analyzed from a microstructure point of view. The objective of this work is to better understand how perforations interact with closed-cell foam microstructure and how it modifies the sound absorption of the foam. A simple two-dimensional microstructural model of the perforated closed-cell metallic foam is presented and numerically solved. A rough three-dimensional conversion of the two-dimensional results is proposed. The results obtained with the calculation method show that the perforated closed-cell foam behaves similarly to a perforated solid; however, its sound absorption is modulated by the foam microstructure, and most particularly by the diameters of both perforation and pore. A comparison with measurements demonstrates that the proposed calculation method yields realistic trends. Some design guides are also proposed.
A closed-loop model of the respiratory system: focus on hypercapnia and active expiration.
Molkov, Yaroslav I; Shevtsova, Natalia A; Park, Choongseok; Ben-Tal, Alona; Smith, Jeffrey C; Rubin, Jonathan E; Rybak, Ilya A
2014-01-01
Breathing is a vital process providing the exchange of gases between the lungs and atmosphere. During quiet breathing, pumping air from the lungs is mostly performed by contraction of the diaphragm during inspiration, and muscle contraction during expiration does not play a significant role in ventilation. In contrast, during intense exercise or severe hypercapnia forced or active expiration occurs in which the abdominal "expiratory" muscles become actively involved in breathing. The mechanisms of this transition remain unknown. To study these mechanisms, we developed a computational model of the closed-loop respiratory system that describes the brainstem respiratory network controlling the pulmonary subsystem representing lung biomechanics and gas (O2 and CO2) exchange and transport. The lung subsystem provides two types of feedback to the neural subsystem: a mechanical one from pulmonary stretch receptors and a chemical one from central chemoreceptors. The neural component of the model simulates the respiratory network that includes several interacting respiratory neuron types within the Bötzinger and pre-Bötzinger complexes, as well as the retrotrapezoid nucleus/parafacial respiratory group (RTN/pFRG) representing the central chemoreception module targeted by chemical feedback. The RTN/pFRG compartment contains an independent neural generator that is activated at an increased CO2 level and controls the abdominal motor output. The lung volume is controlled by two pumps, a major one driven by the diaphragm and an additional one activated by abdominal muscles and involved in active expiration. The model represents the first attempt to model the transition from quiet breathing to breathing with active expiration. The model suggests that the closed-loop respiratory control system switches to active expiration via a quantal acceleration of expiratory activity, when increases in breathing rate and phrenic amplitude no longer provide sufficient ventilation. The model
NASA Technical Reports Server (NTRS)
Hooey, Becky Lee; Gore, Brian Francis; Mahlstedt, Eric; Foyle, David C.
2013-01-01
The objectives of the current research were to develop valid human performance models (HPMs) of approach and land operations; use these models to evaluate the impact of NextGen Closely Spaced Parallel Operations (CSPO) on pilot performance; and draw conclusions regarding flight deck display design and pilot-ATC roles and responsibilities for NextGen CSPO concepts. This document presents guidelines and implications for flight deck display designs and candidate roles and responsibilities. A companion document (Gore, Hooey, Mahlstedt, & Foyle, 2013) provides complete scenario descriptions and results including predictions of pilot workload, visual attention and time to detect off-nominal events.
Enabling comparative modeling of closely related genomes: Example genus Brucella
Faria, José P.; Edirisinghe, Janaka N.; Davis, James J.; Disz, Terrence; Hausmann, Anna; Henry, Christopher S.; Olson, Robert; Overbeek, Ross A.; Pusch, Gordon D.; Shukla, Maulik; Vonstein, Veronika; Wattam, Alice R.
2014-03-08
For many scientific applications, it is highly desirable to be able to compare metabolic models of closely related genomes. In this study, we attempt to raise awareness to the fact that taking annotated genomes from public repositories and using them for metabolic model reconstructions is far from being trivial due to annotation inconsistencies. We are proposing a protocol for comparative analysis of metabolic models on closely related genomes, using fifteen strains of genus Brucella, which contains pathogens of both humans and livestock. This study lead to the identification and subsequent correction of inconsistent annotations in the SEED database, as well as the identification of 31 biochemical reactions that are common to Brucella, which are not originally identified by automated metabolic reconstructions. We are currently implementing this protocol for improving automated annotations within the SEED database and these improvements have been propagated into PATRIC, Model-SEED, KBase and RAST. This method is an enabling step for the future creation of consistent annotation systems and high-quality model reconstructions that will support in predicting accurate phenotypes such as pathogenicity, media requirements or type of respiration.
Cycle-averaged dynamics of a periodically driven, closed-loop circulation model
NASA Technical Reports Server (NTRS)
Heldt, T.; Chang, J. L.; Chen, J. J. S.; Verghese, G. C.; Mark, R. G.
2005-01-01
Time-varying elastance models have been used extensively in the past to simulate the pulsatile nature of cardiovascular waveforms. Frequently, however, one is interested in dynamics that occur over longer time scales, in which case a detailed simulation of each cardiac contraction becomes computationally burdensome. In this paper, we apply circuit-averaging techniques to a periodically driven, closed-loop, three-compartment recirculation model. The resultant cycle-averaged model is linear and time invariant, and greatly reduces the computational burden. It is also amenable to systematic order reduction methods that lead to further efficiencies. Despite its simplicity, the averaged model captures the dynamics relevant to the representation of a range of cardiovascular reflex mechanisms. c2004 Elsevier Ltd. All rights reserved.
NASA Astrophysics Data System (ADS)
Asami, Toshihiko; Nishihara, Osamu
2000-04-01
Recently, Nishihara and Matsuhisa have proposed a new theory for attaining the H(infinity) optimization of a dynamic vibration absorber (DVA) in the linear vibratory systems. The H(infinity) optimization of DVA is a classical optimization problem, and already solved more than 50 years ago. All of us know the solution through the textbook written by Den Hartog. The new theory proposed them gives us the exact algebraic solution of the problem. In the first report, we have expounded the theory and showed the procedure of finding the algebraic solution to a typical performance index (compliance transfer function) of the viscous damped system. In this paper, we will apply this theory to another performance indexes: mobility and accelerance transfer functions for force excitation system, and the absolute and relative displacement responses to acceleration, velocity or displacement input to foundation for motion excitation system. We apply this theory not only the viscous damped system but also the hysteretic damped system. As a result, we found the closed-form exact solutions in every performance indexes when the primary system has no damping. The solutions obtained here are compared with the classical ones solved by the fixed-points theory. We further apply this theory to design of DVAs attached to damped primary systems, and found the closed-form exact solutions to some performance indexes of the hysteretic damped system.
Longman, M.W.
1996-10-01
The Lower Mississippian Lodgepole carbonate buildup reservoir at Dickinson Field in Stark County, North Dakota, has been widely reported as being a Waulsortian (or Waulsortian-like) mound. The term {open_quotes}Waulsortian mound{close_quotes} is used for a variety of Early Mississippian carbonate buildups that share a number of features including an abundance of carbonate mud, a {open_quotes}framework{close_quotes} of organisms such as fenestrate bryozoans and crinoids that tended to trap or baffle sediment, and a general absence of marine-cemented reef framework. Although the age of the Lodgepole mound at Dickinson Field qualifies it to be a Waulsortian mound, petrographic study of cores reveals that the reservoir rocks are quite unlike those in true Waulsortian mounds. Instead of being dominated by carbonate mud, the Lodgepole mound core is dominated by marine cement. Furthermore, ostracods and microbial limestones are common in the mound core where they occur with crinoid debris and small amounts of bryozoan, coral, and brachiopod debris. The abundant microbial limestones and marine cement indicate that the Dickinson mound formed as a lithified reef on the sea floor rather than as a Waulsortian mud mound. The microbial limestones, marine cement, and common ostracods in the mount core, and the fact that the mound nucleated almost directly o top of the Bakken Shale, suggest that the Dickinson Lodgepole mound formed at the site of a submarine spring and gas seep.
Simulation of Fault Arc Based on Different Radiation Models in a Closed Tank
NASA Astrophysics Data System (ADS)
Li, Mei; Zhang, Junpeng; Hu, Yang; Zhang, Hantian; Wu, Yifei
2016-05-01
This paper focuses on the simulation of a fault arc in a closed tank based on the magneto-hydrodynamic (MHD) method, in which a comparative study of three radiation models, including net emission coefficients (NEC), semi-empirical model based on NEC as well as the P1 model, is developed. The pressure rise calculated by the three radiation models are compared to the measured results. Particularly when the semi-empirical model is used, the effect of different boundary temperatures of the re-absorption layer in the semi-empirical model on pressure rise is concentrated on. The results show that the re-absorption effect in the low-temperature region affects radiation transfer of fault arcs evidently, and thus the internal pressure rise. Compared with the NEC model, P1 and the semi-empirical model with 0.7<α<0.83 are more suitable to calculate the pressure rise of the fault arc, where is an adjusted parameter involving the boundary temperature of the re-absorption region in the semi-empirical model. supported by National Key Basic Research Program of China (973 Program) (No. 2015CB251002), National Natural Science Foundation of China (Nos. 51221005, 51177124), the Fundamental Research Funds for the Central Universities, the Program for New Century Excellent Talents in University and Shaanxi Province Natural Science Foundation of China (No. 2013JM-7010)
Modeling of Directional Hardening Based on Non-Associated Flow for Sheet Forming
NASA Astrophysics Data System (ADS)
Yoon, Jeong Whan; Stoughton, Thomas B.
2010-06-01
This work describes a material model for sheet metal forming that takes into account anisotropic hardening under conditions of proportional loading. Conventional isotropic and kinematic hardening models constrain the shape of the yield function to remain fixed throughout plastic deformation, which is not consistent with most test data from aluminum alloys obtained under proportional loading. Conventional hardening models are shown to introduce systemic errors in stresses in different loading conditions at low and high levels of strain that tend to amplify the effect of stress miscalculation on the prediction of springback. A new model is described in which four stress-strain functions are explicitly integrated into the yield criterion in closed form solution. The model is based on non-associated flow so that this integration does not affect the accuracy of the plastic strain components. The model is expected to lead to a significant improvement in stress prediction under conditions dominated by proportional loading, and this is expected to directly improve the accuracy of springback prediction for these processes.
ERIC Educational Resources Information Center
Roisman, Glenn I.
2002-01-01
Interviewed adolescents in grades 9 through 12 to examine family closeness as either mediator or moderator of relationships between intense work and academic engagement. Found that for boys, the family closeness mediational model provided best fit for data; for girls, the moderator model fit best. Found girls were especially vulnerable to negative…
NASA Astrophysics Data System (ADS)
Zhou, Hanying; Nemati, Bijan; Krist, John; Cady, Eric; Prada, Camilo M.; Kern, Brian; Poberezhskiy, Ilya
2016-07-01
JPL has recently passed an important milestone in its technology development for a proposed NASA WFIRST mission coronagraph: demonstration of better than 1x10-8 contrast over broad bandwidth (10%) on both shaped pupil coronagraph (SPC) and hybrid Lyot coronagraph (HLC) testbeds with the WFIRST obscuration pattern. Challenges remain, however, in the technology readiness for the proposed mission. One is the discrepancies between the achieved contrasts on the testbeds and their corresponding model predictions. A series of testbed diagnoses and modeling activities were planned and carried out on the SPC testbed in order to close the gap. A very useful tool we developed was a derived "measured" testbed wavefront control Jacobian matrix that could be compared with the model-predicted "control" version that was used to generate the high contrast dark hole region in the image plane. The difference between these two is an estimate of the error in the control Jacobian. When the control matrix, which includes both amplitude and phase, was modified to reproduce the error, the simulated performance closely matched the SPC testbed behavior in both contrast floor and contrast convergence speed. This is a step closer toward model validation for high contrast coronagraphs. Further Jacobian analysis and modeling provided clues to the possible sources for the mismatch: DM misregistration and testbed optical wavefront error (WFE) and the deformable mirror (DM) setting for correcting this WFE. These analyses suggested that a high contrast coronagraph has a tight tolerance in the accuracy of its control Jacobian. Modifications to both testbed control model as well as prediction model are being implemented, and future works are discussed.
Audebert, Chloe; Bekheit, Mohamed; Bucur, Petru; Vibert, Eric; Vignon-Clementel, Irene E
2017-01-04
The liver function may be degraded after partial liver ablation surgery. Adverse liver hemodynamics have been shown to be associated to liver failure. The link between these hemodynamics changes and ablation size is however poorly understood. This article proposes to explain with a closed-loop lumped model the hemodynamics changes observed during twelve surgeries in pigs. The portal venous tree is modeled with a pressure-dependent variable resistor. The variables measured, before liver ablation, are used to tune the model parameters. Then, the liver partial ablation is simulated with the model and the simulated pressures and flows are compared with post-operative measurements. Fluid infusion and blood losses occur during the surgery. The closed-loop model presented accounts for these blood volume changes. Moreover, the impact of blood volume changes and the liver lobe mass estimations on the simulated variables is studied. The typical increase of portal pressure, increase of liver pressure loss, slight decrease of portal flow and major decrease in arterial flow are quantitatively captured by the model for a 75% hepatectomy. It appears that the 75% decrease in hepatic arterial flow can be explained by the resistance increase induced by the surgery, and that no hepatic arterial buffer response (HABR) mechanism is needed to account for this change. The different post-operative states, observed in experiments, are reproduced with the proposed model. Thus, an explanation for inter-subjects post-operative variability is proposed. The presented framework can easily be adapted to other species circulations and to different pathologies for clinical hepatic applications.
Forming chondrules in impact splashes. I. Radiative cooling model
Dullemond, Cornelis Petrus; Stammler, Sebastian Markus; Johansen, Anders
2014-10-10
The formation of chondrules is one of the oldest unsolved mysteries in meteoritics and planet formation. Recently an old idea has been revived: the idea that chondrules form as a result of collisions between planetesimals in which the ejected molten material forms small droplets that solidify to become chondrules. Pre-melting of the planetesimals by radioactive decay of {sup 26}Al would help produce sprays of melt even at relatively low impact velocity. In this paper we study the radiative cooling of a ballistically expanding spherical cloud of chondrule droplets ejected from the impact site. We present results from numerical radiative transfer models as well as analytic approximate solutions. We find that the temperature after the start of the expansion of the cloud remains constant for a time t {sub cool} and then drops with time t approximately as T ≅ T {sub 0}[(3/5)t/t {sub cool} + 2/5]{sup –5/3} for t > t {sub cool}. The time at which this temperature drop starts t {sub cool} depends via an analytical formula on the mass of the cloud, the expansion velocity, and the size of the chondrule. During the early isothermal expansion phase the density is still so high that we expect the vapor of volatile elements to saturate so that no large volatile losses are expected.
Hydrological Modeling of the Jezero Crater Outlet-Forming Flood
NASA Technical Reports Server (NTRS)
Fassett, Caleb I.; Goudge, Timothy A.
2017-01-01
Jezero crater is a site of prime scientific interest because it was a lake early in Mars history. Preserved clay- and carbonate-bearing sedimentary fans on Jezero's western and northwestern margin (Fig. 2) are accessible to future exploration. Geologic context [1] and stratigraphic analysis of the western fan strongly support the interpretation that these fans were deposited as deltas into the lake. This has helped establish Jezero as one of the final candidate landing sites for Mars 2020. The high level of certainty that Jezero was a lake results from the existence of its outlet valley, which required filling of the crater to form [e.g., 1,4]. Here, we specifically focus on how this outlet valley was carved by the dam breach flood that eroded the eastern crater rim. We have completed preliminary modeling in both 1D and 2D of the outlet's formation.
Advances in Constitutive and Failure Models for Sheet Forming Simulation
NASA Astrophysics Data System (ADS)
Yoon, Jeong Whan; Stoughton, Thomas B.
2016-08-01
Non-Associated Flow Rule (Non-AFR) can be used as a convenient way to account for anisotropic material response in metal deformation processes, making it possible for example, to eliminate the problem of the anomalous yielding in equibiaxial tension that is mistakenly attributed to limitations of the quadratic yield function, but may instead be attributed to the Associated Flow Rule (AFR). Seeing as in Non-AFR based models two separate functions can be adopted for yield and plastic potential, there is no constraint to which models are used to describe each of them. In this work, the flexible combination of two different yield criteria as yield function and plastic potential under Non-AFR is proposed and evaluated. FE simulations were carried so as to verify the accuracy of the material directionalities predicted using these constitutive material models. The stability conditions for non-associated flow connected with the prediction of yield point elongation are also reviewed. Anisotropic distortion hardening is further incorporated under non-associated flow. It has been found that anisotropic hardening makes the noticeable improvements for both earing and spring-back predictions. This presentation is followed by a discussion of the topic of the forming limit & necking, the evidence in favor of stress analysis, and the motivation for the development of a new type of forming limit diagram based on the polar effective plastic strain (PEPS) diagram. In order to connect necking to fracture in metals, the stress-based necking limit is combined with a stress- based fracture criterion in the principal stress, which provides an efficient method for the analysis of necking and fracture limits. The concept for the PEPS diagram is further developed to cover the path-independent PEPS fracture which is compatible with the stress-based fracture approach. Thus this fracture criterion can be utilized to describe the post-necking behavior and to cover nonlinear strain-path. Fracture
Modelling of Deuterium Chemistry in Star-Forming Regions
NASA Astrophysics Data System (ADS)
Roberts, Helen
2005-08-01
Several new multiply deuterated species have been detected over the past three years, including ND3 (van der Tak et al. 2002; Lis et al. 2002), CHD2OH, CD3OH (Parise et al. 2002, 2004), D2S (Vastel et al. 2003), HD2+ (Vastel et al. 2004) and D2CS (Marcelino et al. 2005). In addition, mono-deuterated species have been observed with abundances >10% of their un-deuterated analogues (e.g. CH2DOH observed by Parise et al. 2002; NH2D observed by Saito et al. 2000 and Hatchell 2003). These are remarkable results, given that the underlying abundance of deuterium in the local interstellar medium (ISM) is ˜10-5 times lower than that of hydrogen (Linsky 1998; Sonneborn et al. 2000).Such large enhancements in the abundances of deuterium-bearing molecules can either be due to gas-phase or to grain-surface fractionation. Grain-surface reactions are undoubtedly important in producing saturated species such as methanol, water, ammonia, and hydrogen sulphide. Water ice is observed to be abundant and ubiquitous throughout the ISM, and enhanced abundances of gas-phase NH3, CH3OH, H2CO and H2S (among others) are observed in warmer regions around protostars where grain mantles have evaporated.Recent observational and theoretical evidence suggests that the deuterium fractionation in star-forming regions is set by gas-phase and grain-surface reactions during the cold, dense pre-protostellar phase. For species which form on grain surfaces via H atom addition to CO, N, O and S, the deuterium fractionation on grains comes from the relative amounts of atomic D and H which are accreting from the gas. The observations of deuterated methanol and D2S require that the gas-phase atomic D/H ratio at the time the molecules formed was ≥ 0.1.This paper presents results from chemical models of the prestellar core phase of star formation, showing how this high atomic D/H ratio can be produced, and discusses how models can also be used to look at deuterium fractionation in the protostellar stages of
Singh, Ashish Kumar; Chen, Bo-Yang; Tan, Vincent B C; Tay, Tong-Earn; Lee, Heow-Pueh
2017-02-01
Linear ultrasonics methods based on the principle of reflection, transmission, dissipation of sound waves have been traditionally used to detect delaminations in composite structures. However, when the delamination is in very early stages such that it is almost closed, or closed due to a compressive load, the linear methods may fail to detect such cases of delaminations. Nonlinear acoustics/ultrasonics have shown potential to identify damages in composite structures which are difficult to detect using conventional linear ultrasonic methods. The nonlinear method involves exciting the structure with a sinusoidal signal of certain (or multiple) frequency and observing the vibrations of the structure. The vibrations of the damage region differ significantly from intact regions and can be used to identify the damage. However due to the complex and varying nature of the nonlinear phenomena created by the interaction between the exciting signal and the damage, there are many variables at play which can lead to success or failure of the method. While experiments lead to the establishment of the method to be used as a damage detection technique, numerical simulations can help to explain the various phenomena associated with nonlinearity. This work presents a quick approach to model the nonlinear behavior caused by closed delaminations. The model is validated with a previously available approach for nonlinear vibrations modeling and a comparison is made between the two. The local nature of the nonlinearity enables to map out the area of damage in the structure. Additionally, a few parametric studies are performed to study the effect of various parameters related to the nonlinear phenomenon.
Hampson, Robert E.; Song, Dong; Chan, Rosa H.M.; Sweatt, Andrew J.; Riley, Mitchell R.; Goonawardena, Anushka V.; Marmarelis, Vasilis Z.; Gerhardt, Greg A.; Berger, Theodore W.; Deadwyler, Sam A.
2012-01-01
A major factor involved in providing closed loop feedback for control of neural function is to understand how neural ensembles encode online information critical to the final behavioral endpoint. This issue was directly assessed in rats performing a short-term delay memory task in which successful encoding of task information is dependent upon specific spatiotemporal firing patterns recorded from ensembles of CA3 and CA1 hippocampal neurons. Such patterns, extracted by a specially designed nonlinear multi-input multi-output (MIMO) nonlinear mathematical model, were used to predict successful performance online via a closed loop paradigm which regulated trial difficulty (time of retention) as a function of the “strength” of stimulus encoding. The significance of the MIMO model as a neural prosthesis has been demonstrated by substituting trains of electrical stimulation pulses to mimic these same ensemble firing patterns. This feature was used repeatedly to vary “normal” encoding as a means of understanding how neural ensembles can be “tuned” to mimic the inherent process of selecting codes of different strength and functional specificity. The capacity to enhance and tune hippocampal encoding via MIMO model detection and insertion of critical ensemble firing patterns shown here provides the basis for possible extension to other disrupted brain circuitry. PMID:22498704
NASA Astrophysics Data System (ADS)
Yan, J. P.; Hinderer, M.; Einsele, G.
2002-04-01
In contrast to most previous models for the evolution of closed-basin lakes, we present an integrated model which considers various water budget patterns, clay regradation, SO 4 reduction and subbottom leakage in addition to the classical equilibrium approach of mineral precipitation. The model was applied to Lakes Qinghai and Turkana, which significantly differ in the lithologies of their drainage areas but are representative of the carbonate-rich sedimentary rock province of the Tibet-Qinghai Plateau and the silicate rock province of Eastern Africa. Both lakes are now topographically closed, but to some degree hydrologically open (subbottom leakage). Major results of the mode calculations show that: the lithology controls the ultimate brine which is of Na-(K)-Cl-type for Qinghai Lake and of Na-HCO 3-Cl-type for Lake Turkana. SO 4 reduction delays the onset of sulfatic mineral precipitation and favours the formation of Na-carbonates such as trona at the expense of calcite. Clay mineral regradation plays an important role before the saturation of sulfatic or chlorine minerals is reached. In particular, magnesite formation may be in competition with Mg-bearing clay minerals. Finally, simulations with various hydrological scenarios have shown that the modern hydrochemistry of both lakes cannot be reproduced by simply evaporating inflow water, but reflects long-term accumulation and evolution of solutes by continuous inflow over several thousand years. The diversity of lake water composition within a uniform lithological province can thus be largely ascribed to varying hydrological conditions.
NASA Technical Reports Server (NTRS)
Madden, Michael M.
2014-01-01
In a simultaneous paired approach to closely-spaced parallel runways, a pair of aircraft flies in close proximity on parallel approach paths. The longitudinal separation between the aircraft must be maintained within a range that avoids wake encounters and, if one of the aircraft blunders, avoids collision. To increase operational availability, the approach procedure must accommodate a mixture of aircraft sizes and, consequently, approach speeds. In these procedures, the slower aircraft is placed in the lead position. The faster aircraft maintains separation from the slow aircraft in a dependent operation until final approach and flies independently afterward. Due to the higher approach speed of the fast aircraft, longitudinal separation will decrease during final approach. Therefore, the fast aircraft must position itself before the final approach so that it will remain within the safe range of separation as separation decreases. Given the approach geometry and speed schedule for each aircraft, one can use kinematics to estimate the separation loss between a pair of aircraft. A kinematic model can complement fast-time Monte-Carlo simulations of the approach by enabling a tailored reduction in the variation of starting position for the fast aircraft. One could also implement the kinematic model in ground-based or on-board decision support tools to compute the optimal initial separation for a given pair of aircraft. To better match the auto-coupled flight of real aircraft, the paper derives a kinematic model where the speed schedule is flown using equivalent airspeed. The predicted time of flight using the equivalent airspeed kinematic model compares well against a high-fidelity aircraft simulation performing the same approach. This model also demonstrates a modest increase in the predicted loss of separation when contrasted against a kinematic model that assumes the scheduled speed is true airspeed.
Feasibility of Close-Range Photogrammetric Models for Geographic Information System
Zhou, Luke; /Rice U.
2011-06-22
The objective of this project was to determine the feasibility of using close-range architectural photogrammetry as an alternative three dimensional modeling technique in order to place the digital models in a geographic information system (GIS) at SLAC. With the available equipment and Australis photogrammetry software, the creation of full and accurate models of an example building, Building 281 on SLAC campus, was attempted. After conducting several equipment tests to determine the precision achievable, a complete photogrammetric survey was attempted. The dimensions of the resulting models were then compared against the true dimensions of the building. A complete building model was not evidenced to be obtainable using the current equipment and software. This failure was likely attributable to the limits of the software rather than the precision of the physical equipment. However, partial models of the building were shown to be accurate and determined to still be usable in a GIS. With further development of the photogrammetric software and survey procedure, the desired generation of a complete three dimensional model is likely still feasible.
Modeling corrosion and constituent release from a metal waste form.
Bauer, T. H.; Fink, J. K.; Abraham, D. P.; Johnson, I.; Johnson, S. G.; Wigeland, R. A.
2000-12-04
Several ANL ongoing experimental programs have measured metal waste form (MWF) corrosion and constituent release. Analysis of this data has initiated development of a consistent and quantitative phenomenology of uniform aqueous MWF corrosion. The effort so far has produced a preliminary fission product and actinide release model based on measured corrosion rates and calibrated by immersion test data for a 90 C J-13 and concentrated J-13 solution environment over 1-2 year exposure times. Ongoing immersion tests of irradiated and unirradiated MWF samples using more aggressive test conditions and improved tracking of actinides will serve to further validate, modify, and expand the application base of the preliminary model-including effects of other corrosion mechanisms. Sample examination using both mechanical and spectrographic techniques will better define both the nature and durability of the protective barrier layer. It is particularly important to assess whether the observations made with J-13 solution at 900 C persist under more aggressive conditions. For example, all the multiplicative factors in Table 1 implicitly assume the presence of protective barriers. Under sufficiently aggressive test conditions, such protective barriers may very well be altered or even eliminated.
Mathematical modeling of drug release from lipid dosage forms.
Siepmann, J; Siepmann, F
2011-10-10
Lipid dosage forms provide an interesting potential for controlled drug delivery. In contrast to frequently used poly(ester) based devices for parenteral administration, they do not lead to acidification upon degradation and potential drug inactivation, especially in the case of protein drugs and other acid-labile active agents. The aim of this article is to give an overview on the current state of the art of mathematical modeling of drug release from this type of advanced drug delivery systems. Empirical and semi-empirical models are described as well as mechanistic theories, considering diffusional mass transport, potentially limited drug solubility and the leaching of other, water-soluble excipients into the surrounding bulk fluid. Various practical examples are given, including lipid microparticles, beads and implants, which can successfully be used to control the release of an incorporated drug during periods ranging from a few hours up to several years. The great benefit of mechanistic mathematical theories is the possibility to quantitatively predict the effects of different formulation parameters and device dimensions on the resulting drug release kinetics. Thus, in silico simulations can significantly speed up product optimization. This is particularly useful if long release periods (e.g., several months) are targeted, since experimental trial-and-error studies are highly time-consuming in these cases. In the future it would be highly desirable to combine mechanistic theories with the quantitative description of the drug fate in vivo, ideally including the pharmacodynamic efficacy of the treatments.
Fifel, Karim; Piggins, Hugh; Deboer, Tom
2016-02-01
Parkinson disease is one of the neurodegenerative diseases that benefited the most from the use of non-human models. Consequently, significant advances have been made in the symptomatic treatments of the motor aspects of the disease. Unfortunately, this translational success has been tempered by the recognition of the debilitating aspect of multiple non-motor symptoms of the illness. Alterations of the sleep/wakefulness behavior experienced as insomnia, excessive daytime sleepiness, sleep/wake cycle fragmentation and REM sleep behavior disorder are among the non-motor symptoms that predate motor alterations and inevitably worsen over disease progression. The absence of adequate humanized animal models with the perfect phenocopy of these sleep alterations contribute undoubtedly to the lack of efficient therapies for these non-motor complications. In the context of developing efficient translational therapies, we provide an overview of the strengths and limitations of the various currently available models to replicate sleep alterations of Parkinson's disease. Our investigation reveals that although these models replicate dopaminergic deficiency and related parkinsonism, they rarely display a combination of sleep fragmentation and excessive daytime sleepiness and never REM sleep behavior disorder. In this light, we critically discuss the construct, face and predictive validities of both rodent and non-human primate animals to model the main sleep abnormalities experienced by patients with PD. We conclude by highlighting the need of integrating a network-based perspective in our modeling approach of such complex syndrome in order to celebrate valid translational models.
Numerical Modeling of Tube Forming by HPTR Cold Pilgering Process
NASA Astrophysics Data System (ADS)
Sornin, D.; Pachón-Rodríguez, E. A.; Vanegas-Márquez, E.; Mocellin, K.; Logé, R.
2016-09-01
For new fast-neutron sodium-cooled Generation IV nuclear reactors, the candidate cladding materials for the very strong burn-up are ferritic and martensitic oxide dispersion strengthened grades. Classically, the cladding tube is cold formed by a sequence of cold pilger milling passes with intermediate heat treatments. This process acts upon the geometry and the microstructure of the tubes. Consequently, crystallographic texture, grain sizes and morphologies, and tube integrity are highly dependent on the pilgering parameters. In order to optimize the resulting mechanical properties of cold-rolled cladding tubes, it is essential to have a thorough understanding of the pilgering process. Finite Element Method (FEM) models are used for the numerical predictions of this task; however, the accuracy of the numerical predictions depends not only on the type of constitutive laws but also on the quality of the material parameters identification. Therefore, a Chaboche-type law which parameters have been identified on experimental observation of the mechanical behavior of the material is used here. As a complete three-dimensional FEM mechanical analysis of the high-precision tube rolling (HPTR) cold pilgering of tubes could be very expensive, only the evolution of geometry and deformation is addressed in this work. The computed geometry is compared to the experimental one. It is shown that the evolution of the geometry and deformation is not homogeneous over the circumference. Moreover, it is exposed that the strain is nonhomogeneous in the radial, tangential, and axial directions. Finally, it is seen that the dominant deformation mode of a material point evolves during HPTR cold pilgering forming.
Hybrid Modeling for Testing Intelligent Software for Lunar-Mars Closed Life Support
NASA Technical Reports Server (NTRS)
Malin, Jane T.; Nicholson, Leonard S. (Technical Monitor)
1999-01-01
Intelligent software is being developed for closed life support systems with biological components, for human exploration of the Moon and Mars. The intelligent software functions include planning/scheduling, reactive discrete control and sequencing, management of continuous control, and fault detection, diagnosis, and management of failures and errors. Four types of modeling information have been essential to system modeling and simulation to develop and test the software and to provide operational model-based what-if analyses: discrete component operational and failure modes; continuous dynamic performance within component modes, modeled qualitatively or quantitatively; configuration of flows and power among components in the system; and operations activities and scenarios. CONFIG, a multi-purpose discrete event simulation tool that integrates all four types of models for use throughout the engineering and operations life cycle, has been used to model components and systems involved in the production and transfer of oxygen and carbon dioxide in a plant-growth chamber and between that chamber and a habitation chamber with physicochemical systems for gas processing.
NASA Astrophysics Data System (ADS)
Shimoda, Masatoshi; Shimoide, Kensuke; Shi, Jin-Xing
2016-03-01
Noise reduction by structural geometry optimization has attracted much attention among designers. In the present work, we propose a free-form optimization method for the structural-acoustic design optimization of shell structures to reduce the noise of a targeted frequency or frequency range in an open or closed space. The objective of the design optimization is to minimize the average structural vibration-induced sound pressure at the evaluation points in the acoustic field under a volume constraint. For the shape design optimization, we carry out structural-acoustic coupling analysis and adjoint analysis to calculate the shape gradient functions. Then, we use the shape gradient functions in velocity analysis to update the shape of shell structures. We repeat this process until convergence is confirmed to obtain the optimum shape of the shell structures in a structural-acoustic coupling system. The numerical results for the considered examples showed that the proposed design optimization process can significantly reduce the noise in both open and closed spaces.
NASA Technical Reports Server (NTRS)
Senent, Juan
2011-01-01
The first part of the paper presents some closed-form solutions to the optimal two-impulse transfer between fixed position and velocity vectors on Keplerian orbits when some constraints are imposed on the magnitude of the initial and final impulses. Additionally, a numerically-stable gradient-free algorithm with guaranteed convergence is presented for the minimum delta-v two-impulse transfer. In the second part of the paper, cooperative bargaining theory is used to solve some two-impulse transfer problems when the initial and final impulses are carried by different vehicles or when the goal is to minimize the delta-v and the time-of-flight at the same time.
NASA Astrophysics Data System (ADS)
Barthélémy, Romain; Jacques, Nicolas; Vermeersch, François; Kerampran, Steven
2015-09-01
Metallic foams have known a keen interest in the last decades. Their ability to undergo very large deformations while transmitting low stress levels make them capable of performing functions of protective layers against intense loadings and of energy absorbers, for instance. The behaviour of metal foams varies considerably between quasi-static and dynamic regimes. Those differences can be linked to the strain-rate sensitivity of the skeleton material and to micro-inertial effects (induced by the crushing of the foam cells). In the present work, a micromechanical model has been developed to take into account micro-inertia effects on the macroscopic behaviour of closed-cell foams under dynamic loading conditions. The proposed modelling is based on the dynamic homogenisation procedure introduced by Molinari and Mercier (J. Mech. Phys. Solids 49 (2001) 1497-1516). Within this framework, the macrostress is the sum of two terms. The first one is a static stress, that can be described with any existing model of metal foam. The second contribution is a dynamic stress related to micro-inertia effects. Considering an initially spherical shell as a Representative Volume Element (RVE) of the foam material, a closed-form expression of the dynamic stress was obtained. The proposed modelling was applied to shock propagation in aluminium foams (it should however be noted that the present theory is not restricted to uniaxial deformation but can be applied to arbitrary loadings). From experimental data of the literature, it is observed that incorporating micro-inertia effects allows one to achieve a better description of the foam shock response. This indicates that micro-inertia may have a significant influence on the dynamic behaviour of metallic foams.
Atmosphere behavior in gas-closed mouse-algal systems: An experimental and modelling study
NASA Astrophysics Data System (ADS)
Averner, Maurice M.; Moore, Berrien; Bartholomew, Irene; Wharton, Robert
Concepts of biologically-based regenerative life support systems anticipate the use of photosynthetic organisms for air revitalization. However, mismatches in the rates of production and uptake of oxygen or carbon dioxide between the crew and the plants will lead to an accumulation or depletion of these gases beyond tolerable limits. One method for correcting these atmospheric changes is to use physicochemical devices. This would conflict with the constraint of minimal size and weight imposed upon the successful development of a competitive bioregenerative system. An alternate control strategy is based upon reducing the gas exchange mismatch by manipulation of those environmental parameters known to affect plant or algae gas exchange ratios. We have initiated a research program using a dual approach of mathematical modelling and laboratory experimentation aimed at examining the gas exchange characteristics of artificial animal/plant systems closed to the ambient atmosphere. Our goal is to develop control techniques and management strategies for maintaining the atmospheric levels of carbon dioxide and oxygen at physiological levels. A mathematical model simulating the atmospheric behavior in these systems has been developed and an experimental gas-closed system has been constructed. These will be described and preliminary results will be presented.
Closed-loop supply chain models with considering the environmental impact.
Mohajeri, Amir; Fallah, Mohammad
2014-01-01
Global warming and climate changes created by large scale emissions of greenhouse gases are a worldwide concern. Due to this, the issue of green supply chain management has received more attention in the last decade. In this study, a closed-loop logistic concept which serves the purposes of recycling, reuse, and recovery required in a green supply chain is applied to integrate the environmental issues into a traditional logistic system. Here, we formulate a comprehensive closed-loop model for the logistics planning considering profitability and ecological goals. In this way, we can achieve the ecological goal reducing the overall amount of CO2 emitted from journeys. Moreover, the profitability criterion can be supported in the cyclic network with the minimum costs and maximum service level. We apply three scenarios and develop problem formulations for each scenario corresponding to the specified regulations and investigate the effect of the regulation on the preferred transport mode and the emissions. To validate the models, some numerical experiments are worked out and a comparative analysis is investigated.
Extreme physical phenomena associated with close-in solid exoplanets: Models and consequences
NASA Astrophysics Data System (ADS)
Saxena, Prabal
Solid exoplanets orbiting at very close distances away from their host star are astrophysical laboratories for unique and exotic processes that define everything from their orbit and shape to their atmospheres and interiors. We create models to examine the unique physical environments that these planets inhabit and explore the effects on planetary shape and on atmosphere and resurfacing processes. In particular we examine three related topics. The first topic involves the creation of a model of the atmospheres of synchronously orbiting close in solid planets which examines the potential of mass advection by the atmosphere to deform the planets shape and produce observable surface signatures. This model reproduces and builds upon earlier low dimension atmospheric models produced for Io and Heated Super-Earths by incorporating stellar disk insolation and latent heat considerations and then examines bulk atmospheric mass transport processes on a variety of different close in solid exoplanets. Spatial deposition profiles are then compared to putative sub-stellar magma oceans in order to examine deformation to a planets' shape and potential production of observable surface features. The second is the potential for tidally and rotationally distorted planets in synchronous orbit to produce observational effects and transit signatures which can both confound system characterization and also act as a probe to constrain system and planet properties. In this model we examine a number of different planet-star systems and quantify their potential biases and asphericity signatures in hypothetical transit data. The results indicate that such signatures and biases exceed observational thresholds of a number of current and future surveys and instruments and consequently may be an invaluable probe for exoplanet characterization - in particular they may help to discriminate between rocky super-earths and mini neptunes - a fundamental unresolved question regarding exoplanets. Finally
Main control computer security model of closed network systems protection against cyber attacks
NASA Astrophysics Data System (ADS)
Seymen, Bilal
2014-06-01
The model that brings the data input/output under control in closed network systems, that maintains the system securely, and that controls the flow of information through the Main Control Computer which also brings the network traffic under control against cyber-attacks. The network, which can be controlled single-handedly thanks to the system designed to enable the network users to make data entry into the system or to extract data from the system securely, intends to minimize the security gaps. Moreover, data input/output record can be kept by means of the user account assigned for each user, and it is also possible to carry out retroactive tracking, if requested. Because the measures that need to be taken for each computer on the network regarding cyber security, do require high cost; it has been intended to provide a cost-effective working environment with this model, only if the Main Control Computer has the updated hardware.
A Closed Network Queue Model of Underground Coal Mining Production, Failure, and Repair
NASA Technical Reports Server (NTRS)
Lohman, G. M.
1978-01-01
Underground coal mining system production, failures, and repair cycles were mathematically modeled as a closed network of two queues in series. The model was designed to better understand the technological constraints on availability of current underground mining systems, and to develop guidelines for estimating the availability of advanced mining systems and their associated needs for spares as well as production and maintenance personnel. It was found that: mine performance is theoretically limited by the maintainability ratio, significant gains in availability appear possible by means of small improvements in the time between failures the number of crews and sections should be properly balanced for any given maintainability ratio, and main haulage systems closest to the mine mouth require the most attention to reliability.
Cross sections for production of closed superstrings at high energy colliders in brane world models
Chialva, Diego; Iengo, Roberto; Russo, Jorge G.
2005-05-15
In brane world string models with large extra dimensions, there are processes where fermion and antifermion (or two gluons) can annihilate producing a light particle (e.g. gluon) carrying transverse momentum and a Kaluza-Klein graviton or an excited closed string that propagates in the extra dimensions. In high energy colliders, this process gives a missing-momentum signature. We compute the total cross section for this process within the context of type II superstring theory in the presence of a D-brane. This includes all missing-energy sources for this string-theory model up to s=8M{sub s}{sup 2}, and it can be used to put new limits on the string scale M{sub s}.
Resource Redistribution Mechanism in the Closed Fractal-Cluster Resource Model
NASA Astrophysics Data System (ADS)
Volov, V. T.; Zubarev, A. P.
2016-11-01
The evolutional scenario of the resource distribution in the fractal-cluster system which is identified as the “organism” has been suggested. We propose a model in which the resource redistribution dynamics in the closed system is determined with the ultrametric structure of the system’s space. Moreover, each cluster has its own characteristic time of a transfer to the equilibrium state which is determined with the ultrametric size of the cluster. The general equation which determines this dynamics has been written. For the determined type of the resource transitions among clusters, the solution of this equation has been numerically received. The problem of the parameter identification’s modelling for the real systems has been discussed.
First Experiences with Kinect v2 Sensor for Close Range 3d Modelling
NASA Astrophysics Data System (ADS)
Lachat, E.; Macher, H.; Mittet, M.-A.; Landes, T.; Grussenmeyer, P.
2015-02-01
RGB-D cameras, also known as range imaging cameras, are a recent generation of sensors. As they are suitable for measuring distances to objects at high frame rate, such sensors are increasingly used for 3D acquisitions, and more generally for applications in robotics or computer vision. This kind of sensors became popular especially since the Kinect v1 (Microsoft) arrived on the market in November 2010. In July 2014, Windows has released a new sensor, the Kinect for Windows v2 sensor, based on another technology as its first device. However, due to its initial development for video games, the quality assessment of this new device for 3D modelling represents a major investigation axis. In this paper first experiences with Kinect v2 sensor are related, and the ability of close range 3D modelling is investigated. For this purpose, error sources on output data as well as a calibration approach are presented.
Zeng, Zebing; Sung, Young Mo; Bao, Nina; Tan, Davin; Lee, Richmond; Zafra, José L; Lee, Byung Sun; Ishida, Masatoshi; Ding, Jun; López Navarrete, Juan T; Li, Yuan; Zeng, Wangdong; Kim, Dongho; Huang, Kuo-Wei; Webster, Richard D; Casado, Juan; Wu, Jishan
2012-09-05
Stable open-shell polycyclic aromatic hydrocarbons (PAHs) are of fundamental interest due to their unique electronic, optical, and magnetic properties and promising applications in materials sciences. Chichibabin's hydrocarbon as a classical open-shell PAH has been investigated for a long time. However, most of the studies are complicated by their inherent high reactivity. In this work, two new stable benzannulated Chichibabin's hydrocarbons 1-CS and 2-OS were prepared, and their electronic structure and geometry in the ground state were studied by various experiments (steady-state and transient absorption spectra, NMR, electron spin resonance (ESR), superconducting quantum interference device (SQUID), FT Raman, X-ray crystallographic etc.) and density function theory (DFT) calculations. 1-CS and 2-OS exhibited tunable ground states, with a closed-shell quinoidal structure for 1-CS and an open-shell biradical form for 2-OS. Their corresponding excited-state forms 1-OS and 2-CS were also chemically approached and showed different decay processes. The biradical 1-OS displayed an unusually slow decay to the ground state (1-CS) due to a large energy barrier (95 ± 2.5 kJ/mol) arising from severe steric hindrance during the transition from an orthogonal biradical form to a butterfly-like quinoidal form. The quick transition from the quinoidal 2-CS (excited state) to the orthogonal biradicaloid 2-OS (ground state) happened during the attempted synthesis of 2-CS. Compounds 1-CS and 2-OS can be oxidized into stable dications by FeCl(3) and/or concentrated H(2)SO(4). The open-shell 2-OS also exhibited a large two-photon absorption (TPA) cross section (760 GM at 1200 nm).
Kinetics of color development of melanoidins formed from fructose/amino acid model systems.
Echavarría, A P; Pagán, J; Ibarz, A
2014-03-01
The formation of soluble melanoidins from a single combination of sugar (fructose) and amino acid model systems were evaluated kinetically. The selected amino acids, commonly found in apple juice and highly reactive in the Maillard reaction, were asparagine, aspartic acid, and glutamic acid. The effect of these reagents and the treatment at different temperatures (50 , 85 , and 100 ) during 96 h on the color intensity of the melanoidin formed was measured by absorbance at different wavelengths (280, 325, 405, and 420 nm). The absorbance of the melanoidin formed from all model systems was located on the wavelength of 405 nm, that is, the area of the visible spectrum close to the UV region. The color of the melanoidins was directly measured using the CIELAB color space system. A first-order kinetic model was applied to the evolution of the ΔE * (color difference) and L * (lightness) of the color. The fructose/aspartic acid model system values of a * (redness) and b * (yellowness) were found in the brown-red zone. Therefore, the color development of the melanoidins was influenced by the type of amino acid and temperature. Especially, it is thought that the a * and b * values can be used to explain the differences among the amino acids in the color development of melanoidins.
Modeling Serial Arguments in Close Relationships: The Serial Argument Process Model
ERIC Educational Resources Information Center
Bevan, Jennifer L.; Finan, Andrea; Kaminsky, Allison
2008-01-01
Though an emerging research area, serial argumentation has yet to be cohesively explored from a theoretical lens. The current project thus extends and updates Trapp and Hoff's (1985) original serial argument model by explicating and testing a theoretical process an individual goes through immediately before, during, and after a serial argument…
β-hairpin-forming peptides; models of early stages of protein folding
Lewandowska, Agnieszka; Ołdziej, Stanisław; Liwo, Adam; Scheraga, Harold A.
2010-01-01
Formation of β-hairpins is considered the initial step of folding of many proteins and, consequently, peptides constituting the β-hairpin sequence of proteins (the β-hairpin-forming peptides) are considered as models of early stages of protein folding. In this article, we discuss the results of experimental studies (circular-dichroism, infrared and nuclear magnetic resonance spectroscopy, and differential scanning calorimetry) of the structure of β-hairpin-forming peptides excised from the B1 domain of protein G, which are known to fold on their own. We demonstrate that local interactions at the turn sequence and hydrophobic interactions between nonpolar residues are the dominant structure-determining factors, while there is no convincing evidence that stable backbone hydrogen bonds are formed in these peptides in aqueous solution. Consequently, the most plausible mechanism for folding of the β-hairpin sequence appears to be the broken-zipper mechanism consisting of the following three steps: (i) bending the chain at the turn sequence owing to favorable local interactions, (ii) formation of loose hydrophobic contacts between nonpolar residues, which occur close to the contacts in the native structure of the protein but not exactly in the same position and, finally, (iii) formation of backbone hydrogen bonds and locking the hydrophobic contacts in the native positions as a hydrophobic core develops, sufficient to dehydrate the backbone peptide groups. This mechanism provides sufficient uniqueness (contacts form between residues that become close together because the chain is bent at the turn position) and robustness (contacts need not occur at once in the native positions) for folding a β-hairpin sequence. PMID:20494507
Dorazio, R.M.; Royle, J. Andrew
2003-01-01
We develop a parameterization of the beta-binomial mixture that provides sensible inferences about the size of a closed population when probabilities of capture or detection vary among individuals. Three classes of mixture models (beta-binomial, logistic-normal, and latent-class) are fitted to recaptures of snowshoe hares for estimating abundance and to counts of bird species for estimating species richness. In both sets of data, rates of detection appear to vary more among individuals (animals or species) than among sampling occasions or locations. The estimates of population size and species richness are sensitive to model-specific assumptions about the latent distribution of individual rates of detection. We demonstrate using simulation experiments that conventional diagnostics for assessing model adequacy, such as deviance, cannot be relied on for selecting classes of mixture models that produce valid inferences about population size. Prior knowledge about sources of individual heterogeneity in detection rates, if available, should be used to help select among classes of mixture models that are to be used for inference.
Integration Of Heat Transfer Coefficient In Glass Forming Modeling With Special Interface Element
Moreau, P.; Gregoire, S.; Lochegnies, D.; Cesar de Sa, J.
2007-05-17
Numerical modeling of the glass forming processes requires the accurate knowledge of the heat exchange between the glass and the forming tools. A laboratory testing is developed to determine the evolution of the heat transfer coefficient in different glass/mould contact conditions (contact pressure, temperature, lubrication...). In this paper, trials are performed to determine heat transfer coefficient evolutions in experimental conditions close to the industrial blow-and-blow process conditions. In parallel of this work, a special interface element is implemented in a commercial Finite Element code in order to deal with heat transfer between glass and mould for non-meshing meshes and evolutive contact. This special interface element, implemented by using user subroutines, permits to introduce the previous heat transfer coefficient evolutions in the numerical modelings at the glass/mould interface in function of the local temperatures, contact pressures, contact time and kind of lubrication. The blow-and-blow forming simulation of a perfume bottle is finally performed to assess the special interface element performance.
Integration Of Heat Transfer Coefficient In Glass Forming Modeling With Special Interface Element
NASA Astrophysics Data System (ADS)
Moreau, P.; César de Sá, J.; Grégoire, S.; Lochegnies, D.
2007-05-01
Numerical modeling of the glass forming processes requires the accurate knowledge of the heat exchange between the glass and the forming tools. A laboratory testing is developed to determine the evolution of the heat transfer coefficient in different glass/mould contact conditions (contact pressure, temperature, lubrication…). In this paper, trials are performed to determine heat transfer coefficient evolutions in experimental conditions close to the industrial blow-and-blow process conditions. In parallel of this work, a special interface element is implemented in a commercial Finite Element code in order to deal with heat transfer between glass and mould for non-meshing meshes and evolutive contact. This special interface element, implemented by using user subroutines, permits to introduce the previous heat transfer coefficient evolutions in the numerical modelings at the glass/mould interface in function of the local temperatures, contact pressures, contact time and kind of lubrication. The blow-and-blow forming simulation of a perfume bottle is finally performed to assess the special interface element performance.
NASA Technical Reports Server (NTRS)
Balakrishna, S.; Goglia, G. L.
1979-01-01
The details of the efforts to synthesize a control-compatible multivariable model of a liquid nitrogen cooled, gaseous nitrogen operated, closed circuit, cryogenic pressure tunnel are presented. The synthesized model was transformed into a real-time cryogenic tunnel simulator, and this model is validated by comparing the model responses to the actual tunnel responses of the 0.3 m transonic cryogenic tunnel, using the quasi-steady-state and the transient responses of the model and the tunnel. The global nature of the simple, explicit, lumped multivariable model of a closed circuit cryogenic tunnel is demonstrated.
ERIC Educational Resources Information Center
Bass, Randy; Linkon, Sherry Lee
2008-01-01
While some literary scholars claim that their discipline's research practices do not fit the scholarship of teaching and learning, close reading--the signature critical practice of literary studies--provides a useful model. Close reading involves not only attention to the text but also the integration of text and theory. This article analyzes how…
2016-06-01
Kinases in Schwannoma Formation Using a Novel Genetically Engineered Murine Model that Closely Phenocopies Human NF2 Disease The views, opinions... Human NF2 Disease Form Approved OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per...Functionally, the mean hearing threshold of nearly 60 dB in Postn-Cre+; Nf2flox/flox mice at the age of 10 months is equivalent, as a human analog, of the
Numerical model describing optimization of fibres winding process on open and closed frame
NASA Astrophysics Data System (ADS)
Petrů, M.; Mlýnek, J.; Martinec, T.
2016-08-01
This article discusses a numerical model describing optimization of fibres winding process on open and closed frame. The quality production of said type of composite frame depends primarily on the correct winding of fibers on a polyurethane core. It is especially needed to ensure the correct angles of the fibers winding on the polyurethane core and the homogeneity of individual winding layers. The article describes mathematical model for use an industrial robot in filament winding and how to calculate the trajectory of the robot. When winding fibers on the polyurethane core which is fastened to the robot-end-effector so that during the winding process goes through a fibre-processing head on the basis of the suitably determined robot-end-effector trajectory. We use the described numerical model and matrix calculus to enumerate the trajectory of the robot-end-effector to determine the desired passage of the frame through the fibre-processing head. The calculation of the trajectory was programmed in the Delphi development environment. Relations of the numerical model are important for use a real solving of the passage of a polyurethane core through fibre-processing head.
NASA Astrophysics Data System (ADS)
Carabias-Orti, Julio J.; Cobos, Máximo; Vera-Candeas, Pedro; Rodríguez-Serrano, Francisco J.
2013-12-01
Close-microphone techniques are extensively employed in many live music recordings, allowing for interference rejection and reducing the amount of reverberation in the resulting instrument tracks. However, despite the use of directional microphones, the recorded tracks are not completely free from source interference, a problem which is commonly known as microphone leakage. While source separation methods are potentially a solution to this problem, few approaches take into account the huge amount of prior information available in this scenario. In fact, besides the special properties of close-microphone tracks, the knowledge on the number and type of instruments making up the mixture can also be successfully exploited for improved separation performance. In this paper, a nonnegative matrix factorization (NMF) method making use of all the above information is proposed. To this end, a set of instrument models are learnt from a training database and incorporated into a multichannel extension of the NMF algorithm. Several options to initialize the algorithm are suggested, exploring their performance in multiple music tracks and comparing the results to other state-of-the-art approaches.
Algorithms for a Closed-Loop Artificial Pancreas: The Case for Model Predictive Control
Bequette, B. Wayne
2013-01-01
The relative merits of model predictive control (MPC) and proportional-integral-derivative (PID) control are discussed, with the end goal of a closed-loop artificial pancreas (AP). It is stressed that neither MPC nor PID are single algorithms, but rather are approaches or strategies that may be implemented very differently by different engineers. The primary advantages to MPC are that (i) constraints on the insulin delivery rate (and/or insulin on board) can be explicitly included in the control calculation; (ii) it is a general framework that makes it relatively easy to include the effect of meals, exercise, and other events that are a function of the time of day; and (iii) it is flexible enough to include many different objectives, from set-point tracking (target) to zone (control to range). In the end, however, it is recognized that the control algorithm, while important, represents only a portion of the effort required to develop a closed-loop AP. Thus, any number of algorithms/approaches can be successful—the engineers involved in the design must have experience with the particular technique, including the important experience of implementing the algorithm in human studies and not simply through simulation studies. PMID:24351190
Nonequilibrium models for predicting forms of precipitated manganese oxides
Hem, J.D.; Lind, Carol J.
1983-01-01
Manganese oxides precipitated by bubbling air through 0.01 molar solutions of MnCl2, Mn(NO3)2, MnSO4, or Mn(ClO4)2 at a constantly maintained pH of 8.5 to 9.5 at temperatures of 25??C or higher consisted mainly of hausmannite, Mn3O4. At temperatures near 0??C, but with other conditions the same, the product is feitknechtite, ??MnOOH, except that if the initial solution is MnSO4 and the temperature is near 0??C the product is a mixture of manganite, ??MnOOH and groutite, ??MnOOH. All these oxides are metastable in aerated solution and alter by irreversible processes to more highly oxidized species during aging. A two-step nonequilibrium thermodynamic model predicts that the least stable species, ??MnOOH, should be most readily converted to MnO2. Some preparations of ??MnOOH aged in their native solution at 5??C attained a manganese oxidation state of +3.3 or more after 7 months. Hausmannite aged at 25??C altered to ??MnOOH. The latter is more stable than a or ??MnOOH, and manganese oxidation states above 3.0 were not reached in hausmannite precipitates during 4 months of aging. Initial precipitation of MnCO3 rather than a form of oxide is likely only where oxygen availability is very low. Composition of solutions and oxidation state and morphology of solids were determined during the aging process by chemical analyses, X-ray and electron diffraction and transmission electron micrographs. ?? 1983.
Sheet metal forming optimization by using surrogate modeling techniques
NASA Astrophysics Data System (ADS)
Wang, Hu; Ye, Fan; Chen, Lei; Li, Enying
2017-01-01
Surrogate assisted optimization has been widely applied in sheet metal forming design due to its efficiency. Therefore, to improve the efficiency of design and reduce the product development cycle, it is important for scholars and engineers to have some insight into the performance of each surrogate assisted optimization method and make them more flexible practically. For this purpose, the state-of-the-art surrogate assisted optimizations are investigated. Furthermore, in view of the bottleneck and development of the surrogate assisted optimization and sheet metal forming design, some important issues on the surrogate assisted optimization in support of the sheet metal forming design are analyzed and discussed, involving the description of the sheet metal forming design, off-line and online sampling strategies, space mapping algorithm, high dimensional problems, robust design, some challenges and potential feasible methods. Generally, this paper provides insightful observations into the performance and potential development of these methods in sheet metal forming design.
Close-range geophotogrammetric mapping of trench walls using multi-model stereo restitution software
Coe, J.A.; Taylor, E.M.; Schilling, S.P.
1991-06-01
Methods for mapping geologic features exposed on trench walls have advanced from conventional gridding and sketch mapping to precise close-range photogrammetric mapping. In our study, two strips of small-format (60 {times} 60) stereo pairs, each containing 42 photos and covering approximately 60 m of nearly vertical trench wall (2-4 m high), were contact printed onto eight 205 {times} 255-mm transparent film sheets. Each strip was oriented in a Kern DSR15 analytical plotter using the bundle adjustment module of Multi-Model Stereo Restitution Software (MMSRS). We experimented with several systematic-control-point configurations to evaluate orientation accuracies as a function of the number and position of control points. We recommend establishing control-point columns (each containing 2-3 points) in every 5th photo to achieve the 7-mm Root Mean Square Error (RMSE) accuracy required by our trench-mapping project. 7 refs., 8 figs., 1 tab.
Machine Learning Models for Detection of Regions of High Model Form Uncertainty in RANS
NASA Astrophysics Data System (ADS)
Ling, Julia; Templeton, Jeremy
2015-11-01
Reynolds Averaged Navier Stokes (RANS) models are widely used because of their computational efficiency and ease-of-implementation. However, because they rely on inexact turbulence closures, they suffer from significant model form uncertainty in many flows. Many RANS models make use of the Boussinesq hypothesis, which assumes a non-negative, scalar eddy viscosity that provides a linear relation between the Reynolds stresses and the mean strain rate. In many flows of engineering relevance, this eddy viscosity assumption is violated, leading to inaccuracies in the RANS predictions. For example, in near wall regions, the Boussinesq hypothesis fails to capture the correct Reynolds stress anisotropy. In regions of flow curvature, the linear relation between Reynolds stresses and mean strain rate may be inaccurate. This model form uncertainty cannot be quantified by simply varying the model parameters, as it is rooted in the model structure itself. Machine learning models were developed to detect regions of high model form uncertainty. These machine learning models consisted of binary classifiers that predicted, on a point-by-point basis, whether or not key RANS assumptions were violated. These classifiers were trained and evaluated for their sensitivity, specificity, and generalizability on a database of canonical flows.
Modeling of early stages of island growth during pulsed deposition: Role of closed compact islands
Kotrla, M.; Masin, M.
2011-03-24
After a brief review of recent modeling of growth during Pulsed Laser Deposition (PLD), we present the study of a role of adatom interactions on growth of surface islands during PLD in submonolayer regime. We employ kinetic Monte Carlo simulation with reversible growth. Attachment of monomers to islands is irreversible at low temperatures while it becomes reversible at higher temperatures, small islands become unstable with growing temperature. In the case of real system we have to take into account not only diffusion of monomers but also diffusivity of dimers and larger clusters and theirs stability. Our new code allows us to study processes which proceed on different time scales which are typical in PLD experiments: fast deposition (on scale order of 10{sup -5} s) during individual pulses, and relaxation of a system between pulses (on scale order of 0.1 s). We calculate and compare the temperature dependence of island density for two modes pulsed deposition and continuous Molecular Beam Epitaxy (MBE) growth. The island densities in PLD mode are substantially higher than in MBE mode, provided the temperature is sufficiently high. In the case of PLD, we observe anomalous temperature dependence of the island density in a certain temperature interval. It is due to the interplay between a cluster decay time and an interval between pulses. The cluster decay time depends not only on temperature but also on clusters size and shape. The anomalous behavior is caused by the temperature limited stability of the closed--compact clusters. This scenario was revealed for the simplified model with only nearest-neighbor interaction. Now, it is elucidated further and we also include interaction to second and third neighbors. We analyze role of the closed-compact surface island in kinetics of both growth modes. Furthermore, by varying interactions energies, diffusion barrier and parameters of deposition, we compare results of simulations with the PLD experiment for Fe/Mo system.
Ising t-J model close to half filling: a Monte Carlo study.
Maśka, M M; Mierzejewski, M; Ferraz, A; Kochetov, E A
2009-01-28
Within the recently proposed doped-carrier representation of the projected lattice electron operators we derive a full Ising version of the t-J model. This model possesses the global discrete Z(2) symmetry as a maximal spin symmetry of the Hamiltonian at any values of the coupling constants, t and J. In contrast, in the spin anisotropic limit of the t-J model, usually referred to as the t-J(z) model, the global SU(2) invariance is fully restored at J(z) = 0, so that only the spin-spin interaction has in this model the true Ising form. We discuss a relationship between these two models and the standard isotropic t-J model. We show that the low-energy quasiparticles in all three models share qualitatively similar properties at low doping and small values of J/t. The main advantage of the proposed Ising t-J model over the t-J(z) one is that the former allows for the unbiased Monte Carlo calculations on large clusters of up to 10(3) sites. Within this model we discuss in detail the destruction of the antiferromagnetic (AF) order by doping as well as the interplay between the AF order and hole mobility. We also discuss the effect of the exchange interaction and that of the next-nearest-neighbour hoppings on the destruction of the AF order at finite doping. We show that the short-range AF order is observed in a wide range of temperatures and dopings, much beyond the boundaries of the AF phase. We explicitly demonstrate that the local no-double-occupancy constraint plays the dominant role in destroying the magnetic order at finite doping. Finally, a role of inhomogeneities is discussed.
Exact string theory model of closed timelike curves and cosmological singularities
NASA Astrophysics Data System (ADS)
Johnson, Clifford V.; Svendsen, Harald G.
2004-12-01
We study an exact model of string theory propagating in a space-time containing regions with closed timelike curves (CTCs) separated from a finite cosmological region bounded by a big bang and a big crunch. The model is an nontrivial embedding of the Taub-NUT geometry into heterotic string theory with a full conformal field theory (CFT) definition, discovered over a decade ago as a heterotic coset model. Having a CFT definition makes this an excellent laboratory for the study of the stringy fate of CTCs, the Taub cosmology, and the Milne/Misner-type chronology horizon which separates them. In an effort to uncover the role of stringy corrections to such geometries, we calculate the complete set of α' corrections to the geometry. We observe that the key features of Taub-NUT persist in the exact theory, together with the emergence of a region of space with Euclidean signature bounded by timelike curvature singularities. Although such remarks are premature, their persistence in the exact geometry is suggestive that string theory is able to make physical sense of the Milne/Misner singularities and the CTCs, despite their pathological character in general relativity. This may also support the possibility that CTCs may be viable in some physical situations, and may be a natural ingredient in pre-big bang cosmological scenarios.
Closed-loop, estimator-based model of human posture following reduced gravity exposure.
Newman, D J; Schultz, K U; Rochlis, J L
1996-01-01
A computational and experimental method is employed to provide an understanding of a critical human space flight problem, posture control following reduced gravity exposure. In the case of an emergency egress, astronauts' postural stability could be life saving. It is hypothesized that muscular gains are lowered during reduced gravity exposure, causing a feeling of heavy legs, or a perceived feeling of muscular weakness, upon return to Earth's 1 g environment. We developed an estimator-based model that is verified by replicating spatial and temporal characteristics of human posture and incorporates an inverted pendulum plant in series with a Hill-type muscle model, two feedback pathways, a central nervous system estimator, and variable gains. Results obtained by lowering the variable muscle gain in the model support the hypothesis. Experimentally, subjects were exposed to partial gravity (3/8 g) simulation on a suspension apparatus, then performed exercises postulated to expedite recovery and alleviate the heavy legs phenomenon. Results show that the rms position of the center of pressure increases significantly after reduced gravity exposure. Closed-loop system behavior is revealed, and posture is divided into a short-term period that exhibits higher stochastic activity and persistent trends and a long-term period that shows relatively low stochastic activity and antipersistent trends.
Exact string theory model of closed timelike curves and cosmological singularities
Johnson, Clifford V.; Svendsen, Harald G.
2004-12-15
We study an exact model of string theory propagating in a space-time containing regions with closed timelike curves (CTCs) separated from a finite cosmological region bounded by a big bang and a big crunch. The model is an nontrivial embedding of the Taub-NUT geometry into heterotic string theory with a full conformal field theory (CFT) definition, discovered over a decade ago as a heterotic coset model. Having a CFT definition makes this an excellent laboratory for the study of the stringy fate of CTCs, the Taub cosmology, and the Milne/Misner-type chronology horizon which separates them. In an effort to uncover the role of stringy corrections to such geometries, we calculate the complete set of {alpha}{sup '} corrections to the geometry. We observe that the key features of Taub-NUT persist in the exact theory, together with the emergence of a region of space with Euclidean signature bounded by timelike curvature singularities. Although such remarks are premature, their persistence in the exact geometry is suggestive that string theory is able to make physical sense of the Milne/Misner singularities and the CTCs, despite their pathological character in general relativity. This may also support the possibility that CTCs may be viable in some physical situations, and may be a natural ingredient in pre-big bang cosmological scenarios.
Impact of the volume of gaseous phase in closed reactors on ANC results and modelling
NASA Astrophysics Data System (ADS)
Drapeau, Clémentine; Delolme, Cécile; Lassabatere, Laurent; Blanc, Denise
2016-04-01
The understanding of the geochemical behavior of polluted solid materials is often challenging and requires huge expenses of time and money. Nevertheless, given the increasing amounts of polluted solid materials and related risks for the environment, it is more and more crucial to understand the leaching of majors and trace metals elements from these matrices. In the designs of methods to quantify pollutant solubilization, the combination of experimental procedures with modeling approaches has recently gained attention. Among usual methods, some rely on the association of ANC and geochemical modeling. ANC experiments - Acid Neutralization Capacity - consists in adding known quantities of acid or base to a mixture of water and contaminated solid materials at a given liquid / solid ratio in closed reactors. Reactors are agitated for 48h and then pH, conductivity, redox potential, carbon, majors and heavy metal solubilized are quantified. However, in most cases, the amounts of matrix and water do not reach the total volume of reactors, leaving some space for air (gaseous phase). Despite this fact, no clear indication is given in standard procedures about the effect of this gaseous phase. Even worse, the gaseous phase is never accounted for when exploiting or modeling ANC data. The gaseous phase may exchange CO2 with the solution, which may, in turn, impact both pH and element release. This study lies within the most general framework for the use of geochemical modeling for the prediction of ANC results for the case of pure phases to real phase assemblages. In this study, we focus on the effect of the gaseous phase on ANC experiments on different mineral phases through geochemical modeling. To do so, we use PHREEQC code to model the evolution of pH and element release (including majors and heavy metals) when several matrices are put in contact with acid or base. We model the following scenarios for the gaseous phase: no gas, contact with the atmosphere (open system
17 CFR Appendix to Subpart B of... - Model Forms
Code of Federal Regulations, 2012 CFR
2012-04-01
...) REGULATIONS S-P AND S-AM Regulation S-AM: Limitations on Affiliate Marketing Pt. 248, Subpt. B, App. Appendix... limit marketing offers, contact us : • By telephone: 1-877-###-#### • On the Web: www.—.com • By mail... the Web: www.—.com • By mail: check the box and complete the form below, and send the form to: Do...
17 CFR Appendix to Subpart B of... - Model Forms
Code of Federal Regulations, 2014 CFR
2014-04-01
...) REGULATIONS S-P, S-AM, AND S-ID Regulation S-AM: Limitations on Affiliate Marketing Pt. 248, Subpt. B, App... limit marketing offers, contact us : • By telephone: 1-877-###-#### • On the Web: www.—.com • By mail... the Web: www.—.com • By mail: check the box and complete the form below, and send the form to: Do...
17 CFR Appendix to Subpart B of... - Model Forms
Code of Federal Regulations, 2011 CFR
2011-04-01
...) REGULATIONS S-P AND S-AM Regulation S-AM: Limitations on Affiliate Marketing Pt. 248, Subpt. B, App. Appendix... limit marketing offers, contact us : • By telephone: 1-877-###-#### • On the Web: www.—.com • By mail... the Web: www.—.com • By mail: check the box and complete the form below, and send the form to: Do...
17 CFR Appendix to Subpart B of... - Model Forms
Code of Federal Regulations, 2013 CFR
2013-04-01
...) REGULATIONS S-P AND S-AM Regulation S-AM: Limitations on Affiliate Marketing Pt. 248, Subpt. B, App. Appendix... limit marketing offers, contact us : • By telephone: 1-877-###-#### • On the Web: www.—.com • By mail... the Web: www.—.com • By mail: check the box and complete the form below, and send the form to: Do...
Exactly solvable model for cluster-size distribution in a closed system
NASA Astrophysics Data System (ADS)
Dubrovskii, V. G.
2017-01-01
We obtain an exact solution for the cluster-size distributions in a closed system described by nonlinear rate equations for irreversible homogeneous growth with size-linear agglomeration rates of the form Ks=D (a +s -1 ) for all s ≥1 , where D is the diffusion coefficient, s is the size, and a is a positive constant. The size spectrum is given by the Pólya distribution times a factor that normalizes the first moment of the distribution to unity and zeroes out the monomer concentration at t →∞ . We show that the a value sets a maximum mean size that equals e for large a and tends to infinity only when a →0 . The size distributions are monotonically decreasing in the initial stage, converting to different monomodal shapes with a maximum at s =2 in the course of growth. The variance of the distribution is narrower than Poissonian at large a and broader than Poissonian at small a , with the threshold occurring at a ≅1 . In most cases, the sizes present in the distributions are small and hence can hardly be described by continuum equations.
Gueguen, Erwan; Flores-Kim, Josué; Darwin, Andrew J
2011-10-01
The Yersinia enterocolitica phage shock protein (Psp) stress response is essential for virulence and for survival during the mislocalization of outer membrane secretin proteins. The cytoplasmic membrane proteins PspB and PspC are critical components involved in regulating psp gene expression and in facilitating tolerance to secretin-induced stress. Interactions between PspB and PspC monomers might be important for their functions and for PspC stability. However, little is known about these interactions and there are conflicting reports about the ability of PspC to dimerize. To address this, we have used a combination of independent approaches to systematically analyze the ability of PspB and PspC to form dimers in vivo. Formaldehyde cross-linking of the endogenous chromosomally encoded proteins in Y. enterocolitica revealed discrete complexes corresponding in size to PspB-PspB, PspC-PspC, and PspB-PspC. Bacterial two-hybrid analysis corroborated these protein associations, but an important limitation of the two-hybrid approach was uncovered for PspB. A series of PspB and PspC proteins with unique cysteine substitutions at various positions was constructed. In vivo disulfide cross-linking experiments with these proteins further supported close association between PspB and PspC monomers. Detailed cysteine substitution analysis of predicted leucine zipper-like amphipathic helices in both PspB and PspC suggested that their hydrophobic faces could form homodimerization interfaces.
12 CFR Appendix B to Part 1030 - Model Clauses and Sample Forms
Code of Federal Regulations, 2013 CFR
2013-01-01
... 12 Banks and Banking 8 2013-01-01 2013-01-01 false Model Clauses and Sample Forms B Appendix B to.... 1030, App. B Appendix B to Part 1030—Model Clauses and Sample Forms 1. Modifications. Institutions that.... Institutions may use inserts to a document (see Sample Form B-4) or fill-in blanks (see Sample Forms B-5,...
Zhao, Jin-bo; Wang, Xue-jiao; Chen, Zhao; Ni, Yun-feng; Wang, Ju-zheng; Han, Yong; Zhang, Zhi-pei; Yan, Xiao-long; Li, Xiao-fei
2017-01-01
Our previous research showed that Gankyrin was overexpressed in NSCLC and significantly associated with clinicopathologic features and poor prognosis. In this study, we will explore potential effect of Gankyrin on EMT and metastasis in NSCLC. The ectopic higher expression of Gankyrin markedly increased the migration and invasion in NSCLC cells. In contrast, silencing Gankyrin inhibit this aggressive behavior in NSCLC cells. Further study demonstrated that overexpression of Gankyrin could decrease E-cadherin expression and increase expression of Vimentin and Twist1 at mRNA and protein levels. These data indicated that Gankyrin could facilitate occurrence and development of EMT. Also IHC analysis showed that Gankyrin expression was negatively correlated with E-cadherin expression, while positively correlated with Vimentin and Twist1 expression in NSCLC tissues. The mechanism study finally suggested that the Gankyrin-driven EMT was partially due to IL-6/p-STAT3 and TGF-β/p-SMAD3 pathways activation. Taken together, our data provided a novel mechanism of Gankyrin promoting EMT and metastasis in NSCLC through forming a closed circle with IL-6/p-STAT3 and TGF-β/p-SMAD3 signaling pathway. PMID:27992365
Bayesian Analysis of a Reduced-Form Air Quality Model
Numerical air quality models are being used for assessing emission control strategies for improving ambient pollution levels across the globe. This paper applies probabilistic modeling to evaluate the effectiveness of emission reduction scenarios aimed at lowering ground-level oz...
Density outbursts in a food web model with a closed nutrient cycle
NASA Astrophysics Data System (ADS)
Szwabiński, Janusz
2013-09-01
A spatial three level food web model with a closed nutrient cycle is presented and analyzed via Monte Carlo simulations. The food web consists of three trophic levels. The basal level species (called resources, R) corresponds to primary producers in real ecosystems. The species at an intermediate level (consumers, C) relates to herbivores. It feeds on the resources. The consumers themselves constitute food for the top level species (predators, P), which corresponds to carnivores. The remains of the consumers and predators (detritus, D) provide nutrient for the resources. The time evolution of the model reveals two asymptotic states: an absorbing one with all species being extinct, and a coexisting one, in which concentrations of all species are non-zero. There are two possible ways for the system to reach the absorbing state. In some cases the densities increase very quickly at the beginning of a simulation and then decline slowly and almost monotonically. In others, well pronounced peaks in the R, C and D densities appear regularly before the extinction. Those peaks correspond to density outbursts (waves) traveling through the system. We investigate the mechanisms leading to the waves. In particular, we show that the percolation of the detritus (i.e. the accumulation of nutrients) is necessary for the emergence of the waves. Moreover, our results corroborate the hypothesis that top-level predators play an essential role in maintaining the stability of a food web (top-down control).
Kolikov, Kiril Hristov; Hristozov, Dimo Donchev; Koleva, Radka Paskova; Krustev, Georgi Aleksandrov
2014-01-01
We introduce a close packing model of the particles from the disperse phase of a liquid dispersion. With this model, we find the sediment volumes, the emergent, and the bound dispersion medium. We formulate a new approach for determining the equivalent radii of the particles from the sediment and the emergent (different from the Stokes method). We also describe an easy manner to apply algebraic method for determining the average volumetric mass densities of the ultimate sediment and emergent, as well as the free dispersion medium (without using any pycnometers or densitometers). The masses of the different components and the density of the dispersion phase in the investigated liquid dispersion are also determined by means of the established densities. We introduce for the first time a dimensionless scale for numeric characterization and therefore an index for predicting the sedimentation stability of liquid dispersions in case of straight and/or reverse sedimentation. We also find the quantity of the pure substance (without pouring out or drying) in the dispersion phase of the liquid dispersions. PMID:25136673
Anishkin, Andriy; Akitake, Bradley; Sukharev, Sergei
2008-01-01
Channels from the MscS family are adaptive tension-activated osmolyte release valves that regulate turgor in prokaryotes and volume in plant chloroplasts. The crystal structure of Escherichia coli MscS has provided a starting point for detailed descriptions of its mechanism. However, solved in the absence of the lipid bilayer, this structure may deviate from a native conformation. In this study, we utilized molecular dynamics simulations and a new iterative extrapolated-motion protocol to pack the splayed peripheral TM1 and TM2 transmembrane helices along the central TM3 shaft. This modification restored the tension transmission route between the membrane and the channel gate. We also modeled the structure of the 26-amino acid N-terminal segments that were unresolved in the crystals. The resulting compact conformation, which we believe approximates the closed resting state of MscS, matches the hydrophobic thickness of the lipid bilayer with arginines 46, 54, and 74 facing the polar lipid headgroups. The pore-lining helices in this resting state feature alternative kinks near the conserved G121 instead of the G113 kinks observed in the crystal structure and the transmembrane barrel remains stable in extended molecular dynamics simulations. Further analysis of the dynamics of the pore constriction revealed several moderately asymmetric and largely dehydrated states. Biochemical and patch-clamp experiments with engineered double-cysteine mutants demonstrated cross-linking between predicted adjacent residue pairs, which formed either spontaneously or under moderate oxidation. The L72C-V99C bridge linking more peripheral TM2 to TM3 caused a shift of channel activation to higher pressures. TM3 to TM3 cross-links through the A84C-T93C, S95C-I97C, and A106C-G108C cysteine pairs were shown to lock MscS in a nonconductive state. Normal channel activity in these mutants could be recovered upon disulfide reduction with dithiothreitol. These results confirmed our modeling
12 CFR Appendix G to Part 226 - Open-End Model Forms and Clauses
Code of Federal Regulations, 2011 CFR
2011-01-01
...) (§ 226.15) G-8Rescission Model Form (When Adding a Security Interest) (§ 226.15) G-9Rescission Model Form (When Increasing the Security) (§ 226.15) G-10(A)Applications and Solicitations Model Form (Credit Cards... NOTICE FOR FUTURE USE This notice contains important information about your rights and...
Bayesian analysis of a reduced-form air quality model.
Foley, Kristen M; Reich, Brian J; Napelenok, Sergey L
2012-07-17
Numerical air quality models are being used for assessing emission control strategies for improving ambient pollution levels across the globe. This paper applies probabilistic modeling to evaluate the effectiveness of emission reduction scenarios aimed at lowering ground-level ozone concentrations. A Bayesian hierarchical model is used to combine air quality model output and monitoring data in order to characterize the impact of emissions reductions while accounting for different degrees of uncertainty in the modeled emissions inputs. The probabilistic model predictions are weighted based on population density in order to better quantify the societal benefits/disbenefits of four hypothetical emission reduction scenarios in which domain-wide NO(x) emissions from various sectors are reduced individually and then simultaneously. Cross validation analysis shows the statistical model performs well compared to observed ozone levels. Accounting for the variability and uncertainty in the emissions and atmospheric systems being modeled is shown to impact how emission reduction scenarios would be ranked, compared to standard methodology.
Pressure Modeling of Char-Forming and Laminated Materials.
1983-06-01
terms of rate of total mass loss, flame heighit, upward flame spread rate, and maximum lateral flame dimensions during the spread process . The cnar...flame extent during the spread process . The char-forming materials (pine-wood, particle-board and a rigid, polyurethane foam) are tested in a 900... processes occur. 2. The behavior of the flame spread process at elevated air pressures, for walls composed of a face layer of PMMA with a thick
Genomic comparison of closely related Giant Viruses supports an accordion-like model of evolution.
Filée, Jonathan
2015-01-01
Genome gigantism occurs so far in Phycodnaviridae and Mimiviridae (order Megavirales). Origin and evolution of these Giant Viruses (GVs) remain open questions. Interestingly, availability of a collection of closely related GV genomes enabling genomic comparisons offer the opportunity to better understand the different evolutionary forces acting on these genomes. Whole genome alignment for five groups of viruses belonging to the Mimiviridae and Phycodnaviridae families show that there is no trend of genome expansion or general tendency of genome contraction. Instead, GV genomes accumulated genomic mutations over the time with gene gains compensating the different losses. In addition, each lineage displays specific patterns of genome evolution. Mimiviridae (megaviruses and mimiviruses) and Chlorella Phycodnaviruses evolved mainly by duplications and losses of genes belonging to large paralogous families (including movements of diverse mobiles genetic elements), whereas Micromonas and Ostreococcus Phycodnaviruses derive most of their genetic novelties thought lateral gene transfers. Taken together, these data support an accordion-like model of evolution in which GV genomes have undergone successive steps of gene gain and gene loss, accrediting the hypothesis that genome gigantism appears early, before the diversification of the different GV lineages.
Genomic comparison of closely related Giant Viruses supports an accordion-like model of evolution
Filée, Jonathan
2015-01-01
Genome gigantism occurs so far in Phycodnaviridae and Mimiviridae (order Megavirales). Origin and evolution of these Giant Viruses (GVs) remain open questions. Interestingly, availability of a collection of closely related GV genomes enabling genomic comparisons offer the opportunity to better understand the different evolutionary forces acting on these genomes. Whole genome alignment for five groups of viruses belonging to the Mimiviridae and Phycodnaviridae families show that there is no trend of genome expansion or general tendency of genome contraction. Instead, GV genomes accumulated genomic mutations over the time with gene gains compensating the different losses. In addition, each lineage displays specific patterns of genome evolution. Mimiviridae (megaviruses and mimiviruses) and Chlorella Phycodnaviruses evolved mainly by duplications and losses of genes belonging to large paralogous families (including movements of diverse mobiles genetic elements), whereas Micromonas and Ostreococcus Phycodnaviruses derive most of their genetic novelties thought lateral gene transfers. Taken together, these data support an accordion-like model of evolution in which GV genomes have undergone successive steps of gene gain and gene loss, accrediting the hypothesis that genome gigantism appears early, before the diversification of the different GV lineages. PMID:26136734
A Preliminary and Simplified Closed Brayton Cycle Modeling for a Space Reactor Application
Guimaraes, Lamartine Nogueira Frutuoso; Camillo, Giannino Ponchio
2008-01-21
The Nuclear Energy Division (ENU) of the Institute for Advanced Studies (IEAv) has started a preliminary design study for a Closed Brayton Cycle Loop (CBCL) aimed at a space reactor application. The main objectives of the study are: 1) to establish a starting concept for the CBCL components specifications, and 2) to build a demonstrative simulator of CBCL. This preliminary design study is developing the CBCL around the NOELLE 60290 turbo machine. The actual nuclear reactor study is being conducted independently. Because of that, a conventional heat source is being used for the CBCL, in this preliminary design phase. This paper describes the steady state simulator of the CBCL operating with NOELLE 60290 turbo machine. In principle, several gases are being considered as working fluid, as for instance: air, helium, nitrogen, CO{sub 2} and gas mixtures such as helium and xenon. However, for this first application pure helium will be used as working fluid. Simplified models of heat and mass transfer were developed to simulate thermal components. Future efforts will focus on implementing a graphical interface to display the thermal process variables in steady state and to keep track of the modifications being implemented at the NOELLE 60290 turbo machine in order to build the CBCL.
Khabipova, Diana; Wiaux, Yves; Gruetter, Rolf; Marques, José P
2015-02-15
The aim of this study is to perform a thorough comparison of quantitative susceptibility mapping (QSM) techniques and their dependence on the assumptions made. The compared methodologies were: two iterative single orientation methodologies minimizing the l2, l1TV norm of the prior knowledge of the edges of the object, one over-determined multiple orientation method (COSMOS) and a newly proposed modulated closed-form solution (MCF). The performance of these methods was compared using a numerical phantom and in-vivo high resolution (0.65 mm isotropic) brain data acquired at 7 T using a new coil combination method. For all QSM methods, the relevant regularization and prior-knowledge parameters were systematically changed in order to evaluate the optimal reconstruction in the presence and absence of a ground truth. Additionally, the QSM contrast was compared to conventional gradient recalled echo (GRE) magnitude and R2* maps obtained from the same dataset. The QSM reconstruction results of the single orientation methods show comparable performance. The MCF method has the highest correlation (corr MCF=0.95, r(2)MCF=0.97) with the state of the art method (COSMOS) with additional advantage of extreme fast computation time. The L-curve method gave the visually most satisfactory balance between reduction of streaking artifacts and over-regularization with the latter being overemphasized when the using the COSMOS susceptibility maps as ground-truth. R2* and susceptibility maps, when calculated from the same datasets, although based on distinct features of the data, have a comparable ability to distinguish deep gray matter structures.
NASA Technical Reports Server (NTRS)
Wasson, J. T.; Kallemeyn, G. W.
2002-01-01
We present new data or iron meteorites that are members of group IAB or are closely related to this large group, and we have also reevaluated some of our earlier data for these irons. In the past it was not possible to distinguish IAB and IIICD irons on the basis of their positions on element-Ni diagrams. We now find that plotting, the new and revised data yields six sets of compact fields on element-Au diagrams, each set corresponding to a compositional group. The largest set includes the majority (approximately equal to 70) of irons previously designated IA: We christened this set the IAB main group. The remaining five sets we designate subgroups within the IAB complex. Three of these subgroups have Au contents similar to the main group, and form parallel trends in most element-Ni diagrams. The groups originally designated IIIC and IIID are two of these subgroups: they are now well resolved from each other and from the main group. The other low-Au subgroup has Ni contents just above the main group. Two other IAB subgroups have appreciably higher Au contents than the main group and show weaker compositional links to it. We have named these five subgroups on the basis of their Au and Ni contents. The three subgroups having Au contents similar to the main group are the low-Au (L) subgroups the two others the high-Au (H) subgroups. The Ni contents are designated high (H), medium (M), or low (L). Thus the old group IIID is now the sLH subgroup. the old group IIIC is the sLM subgroup. In addition, eight irons assigned to two grouplets plot between sLL and sLM on most element-Au diagrams. A large number (27) of related irons plot outside these compact fields but nonetheless appear to be sufficiently related to also be included in the IAB complex.
Danilov, V.V.; Laptev, S.S.; Slavin, V.S.
1996-12-31
A new concept of a closed cycle MHD generator without alkali seed has been suggested. The essence of it is the use of the high-energy electron beams technology for a nonuniform gas-plasma flow in MHD channel creation. At the inlet of MHD channel in supersonic flow of noble gas (He) the plasma clots with a density about 10{sup 15} cm{sup {minus}3} are formed by pulsed intense electron beams with energy about 100 keV. Gas flow drives these clots in a cross magnetic field along the MHD channel which has electrodes connected with a load by Faraday`s scheme. Because the nonuniform gas-plasma flow has not the conductivity in the Hall`s EMF direction a Faraday`s current can flow only through the narrow plasma layers. The energy dissipation and Joule`s heating in MHD channel support the nonequilibrium conductivity in these plasma layers. a gas flow pushes current layers and produces electric power at the expense of enthalpy extraction. The key element is a question of plasma layers stability in MHD channel. The most dangerous instability is the overheating instability. it is shown that taking into account the phenomenon of frozen conductivity for recombinated plasma which appears for noble gas at T{sub e} > 4,000 K the regime with {partial_derivative}{sigma}/{partial_derivative}T{sub e} < 0 can be realized. Due to the fulfillment of this condition the overheating instability is effectively suppressed. The numerical simulation has shown that a supersonic gas flow, containing about 4 current layers in MHD channel simultaneously, is braked without shock waves creation. Current layers provide no less than 30% enthalpy extraction and about 80% isentropic efficiency.
The Behavior of Regular Satellites during the Nice Model's Planetary Close Encounters
NASA Astrophysics Data System (ADS)
Nogueira, E. C.; Gomes, R. S.; Brasser, R.
2014-10-01
In order to explain the behavior of the regular satellites of the ice planets during the instability phase of the Nice model, we used numerical simulations to investigate the evolution of the satellite systems when these two planets experienced encounters with the gas giants. For the initial conditions we placed an ice planet in between Jupiter and Saturn, according to the evolution of Nice model simulations in a jumping Jupiter scenario (Brasser et al. 2009). We used the MERCURY integrator (Chambers 1999) and we obtained 101 successful runs which kept all planets, of which 24 were jumping Jupiter cases. Subsequently we performed additional numerical integrations in which the ice giant that encountered a gas giant was started on the same orbit but with its regular satellites included. This is done as follows: For each of the 101 basic runs, we save the orbital elements of all objects in the integration at all close encounter events. Then we performed a backward integration to start the system 100 years before the encounter and re-enacted the forward integration with the regular satellites around the ice giant. The final orbital elements of the satellites with respect to the ice planet were used to restart the integration for the next planetary encounter. If we assume that Uranus is the ice planet that had encounters with a gas giant, we considered the satellites Miranda, Ariel, Umbriel, Titania and Oberon with their present orbits. For Neptune we introduced Triton with an orbit with a 15% larger than the actual semi-major axis to account for the tidal decay from the LHB to present time. We also assume that Triton was captured through binary disruption (Agnor and Hamilton 2006, Nogueira et al. 2011) and its orbit was circularized by tides during the 500 million years before the LHB.
Nicholls, Emma; Stukas, Arthur A
2011-01-01
When threatened with an upward social comparison with a close other in a self-relevant domain, people may reduce either the self-relevance of the ability being compared or their perceived closeness to the other person (Tesser, 1988). Those high in the trait of narcissism may be more likely to push away others who outperform them. Participants and nominated close others completed online measures of narcissism, contingent self-worth, and relationship closeness. Subsequently, participants heard that their friend performed better (or equivalently) on a "competitive spirit" test. Participants higher in narcissism significantly reduced the closeness of their relationships after a threat but did not reduce the relevance of competitiveness to their self-worth.
Indoor Air Quality Building Education and Assessment Model Forms
The Indoor Air Quality Building Education and Assessment Model (I-BEAM) is a guidance tool designed for use by building professionals and others interested in indoor air quality in commercial buildings.
Modeling Chemical and Isotopic Variations in Lab Formed Hydrothermal Carbonates
NASA Technical Reports Server (NTRS)
Niles, P. B.; Leshin, L. A.; Golden, D. C.; Socki, R. A.; Guan, Y.; Ming, D. W.
2005-01-01
Chemical and mineralogical data (e.g. [1]) from Mars suggest that the history of liquid water on the planet was more sporadic in nature than long-lived. The non-equilibrium chemical and isotopic compositions of the carbonates preserved in the martian meteorite ALH84001 are direct evidence of ancient secondary minerals that have not undergone significant diagenesis or stabilization processes typical of long-lived aqueous systems on Earth. Thus secondary minerals and sediments on Mars may primarily record the characteristics of the aqueous environment in which they formed without being significantly overprinted by subsequent diagenetic processes during burial.
NASA Technical Reports Server (NTRS)
Peres, G.; Serio, S.; Vaiana, G.; Acton, L.; Leibacher, J.; Rosner, R.; Pallavicini, R.
1983-01-01
A time-dependent one-dimensional code incorporating energy, momentum and mass conservation equations, and taking the entire solar atmospheric structure into account, is used to investigate the hydrodynamic response of confined magnetic structures to strong heating perturbations. Model calculation results are compared with flare observations which include the light curves of spectral lines formed over a wide range of coronal flare temperatures, as well as determinations of Doppler shifts for the high temperature plasma. It is shown that the numerical simulation predictions are in good overall agreement with the observed flare coronal plasma evolution, correctly reproducing the temporal profile of X-ray spectral lines and their relative intensities. The predicted upflow velocities support the interpretation of the blueshifts as due to evaporation of chromospheric material.
Modeling fluxes and form in landslide-prone terrain
NASA Astrophysics Data System (ADS)
Roering, J. J.; Booth, A. M.; Stock, J. D.
2011-12-01
Landslides dramatically alter the Earth's surface over short timescales. The mass transfer associated with a limited number of slope failures can dominate the sediment budget of a region for decades or longer. The initiation, failure geometry, and runout of individual landslides depend on a range of factors and cannot be predicted from current models. Given these realities of landslide behavior over human timescales, it is challenging to reasonably represent these processes in landscape evolution models. Here, we evaluate the ability of two landslide models, both of which are formulated to apply at geomorphic timescales, to generate topographic patterns and sediment flux rates observed in natural landscapes. Episodic debris flow activity is ubiquitous in steep, low-order mountainous catchments and generates valley networks with low concavity. A physically-based model for debris flow incision (Stock and Dietrich, GSA Bull, 2006) proposes that incision rates depend on the frequency, volume, and velocity of debris flows as well as the density of trigger sites and the state of bedrock weathering in low-order valleys. Valley slope angles are predicted to decline with drainage area according to how these properties vary spatially. We calibrated the model for a well-studied small catchment in the Oregon Coast Range using cosmogenic radionuclide erosion rates and then analyzed the slope-area signature of low-order valleys across much of the Central Oregon Coast Range to explore spatial variations in baselevel lowering. This endeavor shows that baselevel lowering rates vary significantly due to patches of resistant bedrock, drainage reorganization, and tectonic forcing. In regions with weak sedimentary bedrock, earthflows can reduce hillslope gradients, promote gullying, and dominate sediment yield through their downslope translation. A one-dimensional, physically-based model for earthflow-prone hillslope evolution (Booth and Roering, JGR, in press) incorporates earthflow
12 CFR Appendix G to Part 1026 - Open-End Model Forms and Clauses
Code of Federal Regulations, 2014 CFR
2014-01-01
... 12 Banks and Banking 9 2014-01-01 2014-01-01 false Open-End Model Forms and Clauses G Appendix G... Model Clause (Home-equity Plans) (§ 1026.12) G-2(A)Liability for Unauthorized Use Model Clause (Plans Other Than Home-equity Plans) (§ 1026.12) G-3Long-Form Billing-Error Rights Model Form...
A Computer Model of Simple Forms of Learning.
ERIC Educational Resources Information Center
Jones, Thomas L.
A basic unsolved problem in science is that of understanding learning, the process by which people and machines use their experience in a situation to guide future action in similar situations. The ideas of Piaget, Pavlov, Hull, and other learning theorists, as well as previous heuristic programing models of human intelligence, stimulated this…
Forming a Universal Grid for use in Synthesis Modeling
NASA Astrophysics Data System (ADS)
Streubert, M. I.
2006-12-01
Synthesis modeling is a powerful tool for researchers and managers. Its implementation in a coastal embayment requires easy access to many different types of data, from a variety of mediums and sources. A possible approach is to create in ArcGIS a standard shapefile polygon universal grid stretching across the entire embayment. All data received, modeled, and/or collected are then mapped into this grid using ArcMap. Data that fall outside of the correlating cell, or contain many points that fall within the cell, are transformed to produce an optimum representation within the grid. The example presented here has 30m by 30m cells. Each cell contains information from layers joined to it via a field. The fields are described in a header classifying the joined data. This method allows all collected data to be represented at once without having to look farther then an ArcMap attribute table. The attribute tables are not restricted to GIS software and can be viewed in Access, Excel, or any .txt program. In the latter case, the user searches for cells that fall within some small sub-area of the embayment which is of immediate interest. For example this might involve examining data on sediment grain size and modeled wave climate on a particular beach. If the user has ArcMap available then there are more techniques for viewing the data. In ArcMap the grid can be queried, displayed, and extracted allowing users to focus on a particular data type and/or examine available data. The universal grid created for Tampa Bay is an approach to refine the data collection process in any study area. The grid allows users to couple outputs from various models with field data and analyze with a mouse click, without having to leaf through notes, websites, or folders. Examples will be presented of classic rectangular and flexible mesh model grids projected onto a universal grid and synthesized with field data collected over a period of several days by a boat moving through a tidal embayment.
A LabVIEW model incorporating an open-loop arterial impedance and a closed-loop circulatory system.
Cole, R T; Lucas, C L; Cascio, W E; Johnson, T A
2005-11-01
While numerous computer models exist for the circulatory system, many are limited in scope, contain unwanted features or incorporate complex components specific to unique experimental situations. Our purpose was to develop a basic, yet multifaceted, computer model of the left heart and systemic circulation in LabVIEW having universal appeal without sacrificing crucial physiologic features. The program we developed employs Windkessel-type impedance models in several open-loop configurations and a closed-loop model coupling a lumped impedance and ventricular pressure source. The open-loop impedance models demonstrate afterload effects on arbitrary aortic pressure/flow inputs. The closed-loop model catalogs the major circulatory waveforms with changes in afterload, preload, and left heart properties. Our model provides an avenue for expanding the use of the ventricular equations through closed-loop coupling that includes a basic coronary circuit. Tested values used for the afterload components and the effects of afterload parameter changes on various waveforms are consistent with published data. We conclude that this model offers the ability to alter several circulatory factors and digitally catalog the most salient features of the pressure/flow waveforms employing a user-friendly platform. These features make the model a useful instructional tool for students as well as a simple experimental tool for cardiovascular research.
Process modelling and die design concepts for forming aircraft sheet parts
NASA Astrophysics Data System (ADS)
Hatipoğlu, H. A.; Alkaş, C. O.
2016-08-01
This study is about typical sheet metal forming processes applied in aerospace industry including flexform, stretch form and stretch draw. Each process is modelled by using finite element method for optimization. Tensile, bulge, forming limit and friction tests of commonly used materials are conducted for defining the hardening curves, yield loci, anisotropic constants, forming limit curves and friction coefficients between die and sheet. Process specific loadings and boundary conditions are applied to each model. The models are then validated by smartly designed experiments that characterize the related forming processes. Lastly, several examples are given in which those models are used to predict the forming defects before physical forming and necessary die design and process parameter changes are applied accordingly for successful forming operations.
Mechanochemical models for generating biological pattern and form in development
NASA Astrophysics Data System (ADS)
Murray, J. D.; Maini, P. K.; Tranquillo, R. T.
1988-12-01
The central issue in development is the formation of spatial patterns of cells in the early embryo. The mechanisms which generate these patterns are unknown. Here we describe the new Oster-Murray mechanochemical approach to the problem, the elements of which are experimentally well documented. By way of illustration we derive one of the basic models from first principles and apply it to a variety of problems of current interest and research. We specifically discuss the formation of skin organ patterns, such as feather and scale germs, cartilage condensations in the developing vertebrate limb and finally wound healing.
String model for the dynamics of glass-forming liquids.
Pazmiño Betancourt, Beatriz A; Douglas, Jack F; Starr, Francis W
2014-05-28
We test the applicability of a living polymerization theory to describe cooperative string-like particle rearrangement clusters (strings) observed in simulations of a coarse-grained polymer melt. The theory quantitatively describes the interrelation between the average string length L, configurational entropy Sconf, and the order parameter for string assembly Φ without free parameters. Combining this theory with the Adam-Gibbs model allows us to predict the relaxation time τ in a lower temperature T range than accessible by current simulations. In particular, the combined theories suggest a return to Arrhenius behavior near Tg and a low T residual entropy, thus avoiding a Kauzmann "entropy crisis."
Temporal stability of magic-number metal clusters: beyond the shell closing model
NASA Astrophysics Data System (ADS)
Desireddy, Anil; Kumar, Santosh; Guo, Jingshu; Bolan, Michael D.; Griffith, Wendell P.; Bigioni, Terry P.
2013-02-01
The anomalous stability of magic-number metal clusters has been associated with closed geometric and electronic shells and the opening of HOMO-LUMO gaps. Despite this enhanced stability, magic-number clusters are known to decay and react in the condensed phase to form other products. Improving our understanding of their decay mechanisms and developing strategies to control or eliminate cluster instability is a priority, to develop a more complete theory of their stability, to avoid studying mixtures of clusters produced by the decay of purified materials, and to enable technology development. Silver clusters are sufficiently reactive to facilitate the study of the ambient temporal stability of magic-number metal clusters and to begin to understand their decay mechanisms. Here, the solution phase stability of a series of silver:glutathione (Ag:SG) clusters was studied as a function of size, pH and chemical environment. Cluster stability was found to be a non-monotonic function of size. Electrophoretic separations showed that the dominant mechanism involved the redistribution of mass toward smaller sizes, where the products were almost exclusively previously known cluster sizes. Optical absorption spectra showed that the smaller clusters evolved toward the two most stable cluster sizes. The net surface charge was found to play an important role in cluster stabilization although charge screening had no effect on stability, contrary to DLVO theory. The decay mechanism was found to involve the loss of Ag+ ions and silver glutathionates. Clusters could be stabilized by the addition of Ag+ ions and destabilized by either the addition of glutathione or the removal of Ag+ ions. Clusters were also found to be most stable in near neutral pH, where they had a net negative surface charge. These results provide new mechanistic insights into the control of post-synthesis stability and chemical decay of magic-number metal clusters, which could be used to develop design principles
Analysis of forming characteristics of Ta EFP according to material model
NASA Astrophysics Data System (ADS)
Kim, H. J.; Yi, Y. S.; Park, L. J.
2015-09-01
This paper presents numerical analysis result of forming characteristics of Ta explosively formed penetrator (EFP) according to various material models and their values. Dynamic material properties of Ta were measured with static tensile testing machine and Hopkinson pressure bar tests. We used AUTODYN hydrodynamic code to simulate these phenomena. We used three material models, such as Von-Mises model, linear hardening model and Johnson-Cook model. We also compared the numerical results with the EFP forming test data. The numerical results show that material model and its parameter are so important to predict the shape of formed penetrator and Von-Mises model predicts the shape of the formed liner most well. We also analysed the influence of liner thickness on EFP formation using the verified numerical model.
12 CFR Appendix B to Part 230 - Model Clauses and Sample Forms
Code of Federal Regulations, 2014 CFR
2014-01-01
... 12 Banks and Banking 4 2014-01-01 2014-01-01 false Model Clauses and Sample Forms B Appendix B to... SYSTEM (CONTINUED) TRUTH IN SAVINGS (REGULATION DD) Pt. 230, App. B Appendix B to Part 230—Model Clauses and Sample Forms Table of contents B-1—Model Clauses for Account Disclosures (Section 230.4(b))...
12 CFR Appendix B to Part 230 - Model Clauses and Sample Forms
Code of Federal Regulations, 2013 CFR
2013-01-01
... 12 Banks and Banking 4 2013-01-01 2013-01-01 false Model Clauses and Sample Forms B Appendix B to... SYSTEM (CONTINUED) TRUTH IN SAVINGS (REGULATION DD) Pt. 230, App. B Appendix B to Part 230—Model Clauses and Sample Forms Table of contents B-1—Model Clauses for Account Disclosures (Section 230.4(b))...
12 CFR Appendix B to Part 230 - Model Clauses and Sample Forms
Code of Federal Regulations, 2012 CFR
2012-01-01
... 12 Banks and Banking 4 2012-01-01 2012-01-01 false Model Clauses and Sample Forms B Appendix B to... SYSTEM (CONTINUED) TRUTH IN SAVINGS (REGULATION DD) Pt. 230, App. B Appendix B to Part 230—Model Clauses and Sample Forms Table of contents B-1—Model Clauses for Account Disclosures (Section 230.4(b))...
12 CFR Appendix G to Part 226 - Open-End Model Forms and Clauses
Code of Federal Regulations, 2010 CFR
2010-01-01
... and Clauses G-1Balance-Computation Methods Model Clauses (§§ 226.6 and 226.7) G-2Liability for...) G-9Rescission Model Form (When Increasing the Security) (§ 226.15) G-10(A)Applications and Solicitations Model Forms (Credit Cards) (§ 226.5a(b)) G-10(B)Applications and Solicitations Sample (Credit...
Phase equilibria in model surfactants forming Langmuir monolayers.
Ramírez, E; Santana, A; Cruz, A; López, G E
2007-12-14
The study of Langmuir monolayers has generated the attention of researchers because of their unique properties and their not well understood phase equilibrium. These monolayers exhibit interesting phase diagrams where the unusual liquid-liquid equilibrium can be observed for a single component monolayer. Monte Carlo computer simulations in the virtual Gibbs ensemble were used to obtain the phase diagram of Langmuir monolayers. The liquid-vapor and liquid-liquid phase equilibria were considered by constructing the Cailletet-Mathias phase diagrams. By using the Ising model and the rectilinear approximations the identification of the critical properties for both equilibria was determined. These critical parameters were calculated as a function of the strength of the interaction between the surfactant molecules and the aqueous subphase. As a result, we have identified the coexistence between a liquid expanded state (LES)-vapor and the liquid condensed state-LES, in agreement with experimental and theoretical evidence in the literature. We obtained a clear separation of phases and a strong dependence on the strength of the solvent used. Namely, as the interaction between the solvent and the head of the surfactant increases, the critical properties also increase. Equilibrium states were characterized by computing thermodynamic quantities as a function of temperature and solvent strength.
Modelling fast forms of visual neural plasticity using a modified second-order motion energy model.
Pavan, Andrea; Contillo, Adriano; Mather, George
2014-12-01
The Adelson-Bergen motion energy sensor is well established as the leading model of low-level visual motion sensing in human vision. However, the standard model cannot predict adaptation effects in motion perception. A previous paper Pavan et al.(Journal of Vision 10:1-17, 2013) presented an extension to the model which uses a first-order RC gain-control circuit (leaky integrator) to implement adaptation effects which can span many seconds, and showed that the extended model's output is consistent with psychophysical data on the classic motion after-effect. Recent psychophysical research has reported adaptation over much shorter time periods, spanning just a few hundred milliseconds. The present paper further extends the sensor model to implement rapid adaptation, by adding a second-order RC circuit which causes the sensor to require a finite amount of time to react to a sudden change in stimulation. The output of the new sensor accounts accurately for psychophysical data on rapid forms of facilitation (rapid visual motion priming, rVMP) and suppression (rapid motion after-effect, rMAE). Changes in natural scene content occur over multiple time scales, and multi-stage leaky integrators of the kind proposed here offer a computational scheme for modelling adaptation over multiple time scales.
Inverse modeling of groundwater flow in the semiarid evaporitic closed basin of Los Monegros, Spain
NASA Astrophysics Data System (ADS)
Samper-Calvete, F. J.; García-Vera, M. A.
Only minor attention has been given in the past to the study of closed-basin hydrogeology in evaporitic environments, because these basins usually contain poor-quality groundwater. The motivation for hydrogeological research in the Los Monegros area in northeastern Spain was the approval in 1986 of a large irrigation project in the Ebre River basin. The irrigation of 60,000 ha is planned, partly in an evaporitic closed basin containing playa lakes. The project has given rise to environmental concerns. The evaluation of the hydrologic impacts of irrigation requires quantifying properly the hydrogeology of the area. With the available information, a conceptual hydrogeological model was formulated that identifies two main aquifers connected through a leaky aquitard. On the basis of the conceptual model, a numerical model was calibrated under steady-state conditions using the method of maximum-likelihood automatic parameter estimation (Carrera and Neuman, 1986a). The calibrated model reproduces the measured hydraulic heads fairly well and is consistent with independent information on groundwater discharge. By the solution of the inverse problem, reliable parameter estimates were obtained. It is concluded that anisotropy plays a major role in some parts of the lower aquifer. The geometric average of model conductivity is almost two orders of magnitude larger than the average conductivity derived from small-scale field tests. This scale effect in hydraulic conductivity is consistent with the findings of Neuman (1994) and Sánchez-Vila et al. (1996). Résumé Dans le passé, on s'est peu intéresséà l'hydrogéologie des bassins fermés en milieu évaporitique, parce que ces bassins possèdent en général de l'eau souterraine de qualité médiocre. L'intérêt porté aux recherches hydrogéologiques dans la région de Los Monegros, dans le nord-est de l'Espagne est dûà l'approbation en 1986 d'un vaste projet d'irrigation dans le bassin de l'Ebre. L'irrigation de 60000
Performance and Mass Modeling Subtleties in Closed-Brayton-Cycle Space Power Systems
NASA Technical Reports Server (NTRS)
Barrett, Michael J.; Johnson, Paul K.
2005-01-01
Contents include the following: 1. Closed-Brayton-cycle (CBC) thermal energy conversion is one available option for future spacecraft and surface systems. 2. Brayton system conceptual designs for milliwatt to megawatt power converters have been developed 3. Numerous features affect overall optimized power conversion system performance: Turbomachinery efficiency. Heat exchanger effectiveness. Working-fluid composition. Cycle temperatures and pressures.
NASA Astrophysics Data System (ADS)
Everett, Jason D.; Baird, Mark E.; Suthers, Iain M.
2007-05-01
A spatially resolved, eleven-box ecological model is presented for an Intermittently Closed and Open Lake or Lagoon (ICOLL), configured for Smiths Lake, NSW Australia. ICOLLs are characterised by low flow from the catchment and a dynamic sand bar blocking oceanic exchange, which creates two distinct phases - open and closed. The process descriptions in the ecological model are based on a combination of physical and physiological limits to the processes of nutrient uptake, light capture by phytoplankton and predator-prey interactions. An inverse model is used to calculate mixing coefficients from salinity observations. When compared to field data, the ecological model obtains a fit for salinity, nitrogen, phosphorus, chlorophyll a and zooplankton which is within 1.5 standard deviations of the mean of the field data. Simulations show that nutrient limitation (nitrogen and phosphorus) is the dominant factor limiting growth of the autotrophic state variables during both the open and closed phases of the lake. The model is characterised by strong oscillations in phytoplankton and zooplankton abundance, typical of predator-prey cycles. There is an increase in the productivity of phytoplankton and zooplankton during the open phase. This increased productivity is exported out of the lagoon with a net nitrogen export from water column variables of 489 and 2012 mol N d -1 during the two studied openings. The model is found to be most sensitive to the mortality and feeding efficiency of zooplankton.
Modeling glacier beds in the Austrian Alps: How many lakes will form in future?
NASA Astrophysics Data System (ADS)
Koehler, Dominik; Geilhausen, Martin; Linsbauer, Andreas
2014-05-01
Glacial retreat exposes landscapes with relief characteristics greatly differing from the former ice covered surfaces. If glacial retreat exposes natural basins capable of forming proglacial lakes, then the downstream hydrologic and geomorphic systems in such catchments will be significantly altered due to discharge modifications, sediment trapping, decoupling effects and long term sediment storage (e.g. Geilhausen et al. 2013). Further implications are related to hydropower management, tourism and natural hazards. Consequently, sound knowledge of present day glacier beds ("proglacial zones of tomorrow") and in particular the total number, locations and characteristics of overdeepenings are of importance. For Austria, however, this important information about significant future changes of high alpine regions is yet missing. An interdisciplinary research project is currently in preparation to close this gap. This paper presents results of a pilot study. We used a novel GIS-based approach (GlabTop, cf. Linsbauer et al. 2012) to compute approximate glacier beds in the Austrian Alps. GlabTop ('Glacier bed Topography') is based on an empirical relation between average basal shear stress and elevation range of individual glaciers and makes use of digital elevation models (DEM), glacier outlines and branch lines (i.e. a set of lines covering all important glacier branches). DEMs and glacier outlines were derived from the Austrian glacier inventory (1998) and branch lines were manually digitized. The inventory includes 911 glaciers of which 876 (96%) were considered and 35 were excluded due to size restrictions (< 0.01 km²) or insufficient DEM coverage. We found 165 overdeepenings (> 0.01 km²) with the potential of forming proglacial lakes when glacier retreat reveals the bed. The total area and volume of all overdeepenings is approx. 10 km² and 236 Mio m³ respectively and 33 lakes will be larger than 1 km³. A total glacier volume of 16 ± 5 km³ with an average ice
Modeling the spatial distribution of fragments formed from tidally disrupted stars
NASA Astrophysics Data System (ADS)
Girma, Eden; Guillochon, James
2017-01-01
Roughly once every 104 years, a star passes close enough to the supermassive black hole Sgr A* at the center of the Milky Way to be pulled apart by the black hole’s tidal forces. The star is then ‘spaghettified’ into a long stream of mass, with approximately one half being bound to Sgr A* and the other half unbound. Hydrodynamical simulations of this process have revealed that within this stream, the local self-gravity dominates the tidal field of Sgr A*. This residual self-gravity allows for planetary-mass fragments to form along the stream that are then shot out into the galaxy at velocities determined by a spread of binding energies. We develop a Monte Carlo code in Python that models and plots the evolving position of these fragments for a variety of initial conditions that are likely realized in nature. This code utilizes an n-body integrator to differentially solve for the position, velocity, and acceleration of each fragment at every time step. We find that the while the most unbound fragments seem to escape the galaxy entirely, there could potentially be fragments travelling within a few hundred parsecs of our solar system.
12 CFR Appendix B to Part 707 - Model Clauses and Sample Forms
Code of Federal Regulations, 2014 CFR
2014-01-01
... 12 Banks and Banking 7 2014-01-01 2014-01-01 false Model Clauses and Sample Forms B Appendix B to...) Account Disclosures) B-10—Sample Form (Periodic Statement) B-11—Sample Form (Rate and Fee Schedule) B-12... terms, leaving the decision instead to each credit union's board of directors. 12 CFR 204.2(c)(2)....
12 CFR Appendix C to Part 222 - Model Forms for Opt-Out Notices
Code of Federal Regulations, 2012 CFR
2012-01-01
... SYSTEM FAIR CREDIT REPORTING (REGULATION V) Pt. 222, App. C Appendix C to Part 222—Model Forms for Opt... limit marketing offers, contact us : • By telephone: 1-877-###-#### • On the Web: www.---.com • By mail... the Web: www.---.com • By mail: Check the box and complete the form below, and send the form to:...
12 CFR Appendix B to Part 1030 - Model Clauses and Sample Forms
Code of Federal Regulations, 2013 CFR
2013-01-01
... 12 Banks and Banking 8 2013-01-01 2013-01-01 false Model Clauses and Sample Forms B Appendix B to.... 1030, App. B Appendix B to Part 1030—Model Clauses and Sample Forms Table of Contents B-1—Model Clauses for Account Disclosures (Section 1030.4(b)) B-2—Model Clauses for Change in Terms (Section...
12 CFR Appendix B to Part 1030 - Model Clauses and Sample Forms
Code of Federal Regulations, 2012 CFR
2012-01-01
... 12 Banks and Banking 8 2012-01-01 2012-01-01 false Model Clauses and Sample Forms B Appendix B to.... 1030, App. B Appendix B to Part 1030—Model Clauses and Sample Forms Table of Contents B-1—Model Clauses for Account Disclosures (Section 1030.4(b)) B-2—Model Clauses for Change in Terms (Section...
12 CFR Appendix B to Part 230 - Model Clauses and Sample Forms
Code of Federal Regulations, 2011 CFR
2011-01-01
... 12 Banks and Banking 3 2011-01-01 2011-01-01 false Model Clauses and Sample Forms B Appendix B to... SYSTEM TRUTH IN SAVINGS (REGULATION DD) Pt. 230, App. B Appendix B to Part 230—Model Clauses and Sample Forms Table of contents B-1—Model Clauses for Account Disclosures (Section 230.4(b)) B-2—Model...
New population synthesis model Preliminary results for close double white dwarf populations
NASA Astrophysics Data System (ADS)
Toonen, Silvia; Nelemans, Gijs; Portegies Zwart, Simon F.
2010-11-01
An update is presented to the software package SeBa (Portegies Zwart and Verbunt [1], Nelemans et al. [2]) for simulating single star and binary evolution in which new stellar evolution tracks (Hurley et al. [3]) have been implemented. SeBa is applied to study the population of close double white dwarf and the delay time distribution of double white dwarf mergers that may lead to Supernovae Type Ia.
A New Population Synthesis Model: Preliminary Results for Close Double White Dwarf Populations
NASA Astrophysics Data System (ADS)
Toonen, Silvia; Nelemans, Gijs; Portegies Zwart, Simon F.
2010-12-01
An update is presented to the software package SeBa (Portegies Zwart and Verbunt [1], Nelemans et al. [2]) for simulating single star and binary evolution in which new stellar evolution tracks (Hurley et al. [3]) have been implemented. SeBa is applied to study the population of close double white dwarf and the delay time distribution of double white dwarf mergers that may lead to Supernovae Type Ia.
25 CFR 162.402 - Is there a model business lease form?
Code of Federal Regulations, 2014 CFR
2014-04-01
... 25 Indians 1 2014-04-01 2014-04-01 false Is there a model business lease form? 162.402 Section 162.402 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER LEASES AND PERMITS... is no model business lease form because of the need for flexibility in negotiating and...
Revising Medical Consent Forms: An Empirical Model and Test. CDC Technical Report No. 2.
ERIC Educational Resources Information Center
Kaufer, David S.; And Others
1983-01-01
Noting that medical consent forms traditionally have been so full of medical and legal jargon that they have been impossible for even the educated layperson to understand, this paper presents a model for revising medical consent forms to make them more comprehensible. After describing the model, the paper explains each step involved in using it,…
17 CFR 248.2 - Model privacy form: rule of construction.
Code of Federal Regulations, 2013 CFR
2013-04-01
... (CONTINUED) REGULATIONS S-P AND S-AM Regulation S-P: Privacy of Consumer Financial Information and Safeguarding Personal Information § 248.2 Model privacy form: rule of construction. (a) Model privacy form. Use... CFTC financial privacy rules by futures commission merchants and introducing brokers. Except...
17 CFR 248.2 - Model privacy form: rule of construction.
Code of Federal Regulations, 2012 CFR
2012-04-01
... (CONTINUED) REGULATIONS S-P AND S-AM Regulation S-P: Privacy of Consumer Financial Information and Safeguarding Personal Information § 248.2 Model privacy form: rule of construction. (a) Model privacy form. Use... CFTC financial privacy rules by futures commission merchants and introducing brokers. Except...
17 CFR 248.2 - Model privacy form: rule of construction.
Code of Federal Regulations, 2011 CFR
2011-04-01
... (CONTINUED) REGULATIONS S-P AND S-AM Regulation S-P: Privacy of Consumer Financial Information and Safeguarding Personal Information § 248.2 Model privacy form: rule of construction. (a) Model privacy form. Use... CFTC financial privacy rules by futures commission merchants and introducing brokers. Except...
17 CFR 248.2 - Model privacy form: rule of construction.
Code of Federal Regulations, 2014 CFR
2014-04-01
... (CONTINUED) REGULATIONS S-P, S-AM, AND S-ID Regulation S-P: Privacy of Consumer Financial Information and Safeguarding Personal Information § 248.2 Model privacy form: rule of construction. (a) Model privacy form. Use... CFTC financial privacy rules by futures commission merchants and introducing brokers. Except...
12 CFR Appendix C to Part 1022 - Model Forms for Opt-Out Notices
Code of Federal Regulations, 2012 CFR
2012-01-01
...) Pt. 1022, App. C Appendix C to Part 1022—Model Forms for Opt-Out Notices a. Although use of the model... limit marketing offers, contact us : • By telephone: 1-(877) ###-#### • On the Web: www.—.com • By mail... the Web: www.—.com • By mail: Check the box and complete the form below, and send the form to: —Do...
16 CFR Appendix C to Part 698 - Model Forms for Affiliate Marketing Opt-Out Notices
Code of Federal Regulations, 2012 CFR
2012-01-01
... ACT MODEL FORMS AND DISCLOSURES Pt. 698, App. C Appendix C to Part 698—Model Forms for Affiliate...: 1-877-###-#### — On the Web: www.—.com — By mail: check the box and complete the form below, and... marketing offers, contact us : — By telephone: 1-877-###-#### — On the Web: www.—.com — By mail: check...
12 CFR Appendix C to Part 1022 - Model Forms for Opt-Out Notices
Code of Federal Regulations, 2013 CFR
2013-01-01
...) Pt. 1022, App. C Appendix C to Part 1022—Model Forms for Opt-Out Notices a. Although use of the model... limit marketing offers, contact us : • By telephone: 1-(877) ###-#### • On the Web: www.—.com • By mail... the Web: www.—.com • By mail: Check the box and complete the form below, and send the form to: —Do...
16 CFR Appendix C to Part 698 - Model Forms for Affiliate Marketing Opt-Out Notices
Code of Federal Regulations, 2010 CFR
2010-01-01
... ACT MODEL FORMS AND DISCLOSURES Pt. 698, App. C Appendix C to Part 698—Model Forms for Affiliate...: 1-877-###-#### — On the Web: www.—.com — By mail: check the box and complete the form below, and... marketing offers, contact us : — By telephone: 1-877-###-#### — On the Web: www.—.com — By mail: check...
Family Members Affected by a Close Relative's Addiction: The Stress-Strain-Coping-Support Model
ERIC Educational Resources Information Center
Orford, Jim; Copello, Alex; Velleman, Richard; Templeton, Lorna
2010-01-01
This article outlines the stress-strain-coping-support (SSCS) model which underpins the whole programme of work described in this supplement. The need for such a model is explained: previous models of substance misuse and the family have attributed dysfunction or deficiency to families or family members. In contrast, the SSCS model assumes that…
1998-07-06
tyrosine (3-AT) and luminol , and a simpler but closely related polymer (poly-3-AT) is prepared by the action of nitrite ion on 3-AT alone. Both...and poly-3-AT. Diazotized luminol (i.e., luminol diazonium) has been shown to be an excellent sonochemiluminescent agent, and DALM’S luminescent...properties, which include a thermochemiluninescent response to dissolved carbon dioxide, probably derive from diazotized luminol and its products
NASA Astrophysics Data System (ADS)
Hoffmann, Mathias; Jurisch, Nicole; Albiac Borraz, Elisa; Hagemann, Ulrike; Sommer, Michael; Augustin, Jürgen
2015-04-01
Closed chamber measurements are widely used for determining the CO2 exchange of small-scale or heterogeneous ecosystems. Among the chamber design and operational handling, the data processing procedure is a considerable source of uncertainty of obtained results. We developed a standardized automatic data processing algorithm, based on the language and statistical computing environment R© to (i) calculate measured CO2 flux rates, (ii) parameterize ecosystem respiration (Reco) and gross primary production (GPP) models, (iii) optionally compute an adaptive temperature model, (iv) model Reco, GPP and net ecosystem exchange (NEE), and (v) evaluate model uncertainty (calibration, validation and uncertainty prediction). The algorithm was tested for different manual and automatic chamber measurement systems (such as e.g. automated NEE-chambers and the LI-8100A soil CO2 Flux system) and ecosystems. Our study shows that even minor changes within the modelling approach may result in considerable differences of calculated flux rates, derived photosynthetic active radiation and temperature dependencies and subsequently modeled Reco, GPP and NEE balance of up to 25%. Thus, certain modeling implications will be given, since automated and standardized data processing procedures, based on clearly defined criteria, such as statistical parameters and thresholds are a prerequisite and highly desirable to guarantee the reproducibility, traceability of modelling results and encourage a better comparability between closed chamber based CO2 measurements.
SPICE modeling of a resolver-to-digital converter for closed loop simulations of brushless dc motors
NASA Astrophysics Data System (ADS)
Chen, Jesse E.; Rodriguez, Francis D.
Recent SPICE models of two-phase brushless dc motors explicitly include the sinusoidal modulation of drive currents. Resolvers and resolver-to-digital converters (RDC) often provide motor drives with a measurement of shaft angle for sinusoidal modulation of motor currents. A novel SPICE-compatible resolver-to-digital converter model allows SPICE simulation of RDC signal processing effects. The authors review the SPICE brushless dc motor model, compare simulations of the resolver-to-digital converter to lab measurements, and discuss the closed-loop effects of a triangular carrier.
Zwawi, Mohammed A; Moslehy, Faissal A; Rose, Christopher; Huayamave, Victor; Kassab, Alain J; Divo, Eduardo; Jones, Brendan J; Price, Charles T
2016-10-20
This study utilized a computational biomechanical model and applied the least energy path principle to investigate two pathways for closed reduction of high grade infantile hip dislocation. The principle of least energy when applied to moving the femoral head from an initial to a final position considers all possible paths that connect them and identifies the path of least resistance. Clinical reports of severe hip dysplasia have concluded that reduction of the femoral head into the acetabulum may occur by a direct pathway over the posterior rim of the acetabulum when using the Pavlik harness, or by an indirect pathway with reduction through the acetabular notch when using the modified Hoffman-Daimler method. This computational study also compared the energy requirements for both pathways. The anatomical and muscular aspects of the model were derived using a combination of MRI and OpenSim data. Results of this study indicate that the path of least energy closely approximates the indirect pathway of the modified Hoffman-Daimler method. The direct pathway over the posterior rim of the acetabulum required more energy for reduction. This biomechanical analysis confirms the clinical observations of the two pathways for closed reduction of severe hip dysplasia. The path of least energy closely approximated the modified Hoffman-Daimler method. Further study of the modified Hoffman-Daimler method for reduction of severe hip dysplasia may be warranted based on this computational biomechanical analysis. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.
SOLPS modeling of the effect on plasma detachment of closing the lower divertor in DIII-D
NASA Astrophysics Data System (ADS)
Sang, C. F.; Stangeby, P. C.; Guo, H. Y.; Leonard, A. W.; Covele, B.; Lao, L. L.; Moser, A. L.; Thomas, D. M.
2017-02-01
Scrape-off layer plasma simulation modeling has been carried out to assess the effect of tightly closing the lower divertor in DIII-D, which at present is almost fully open, on the achievement of cold dissipative/detached divertor conditions. To isolate the impact of other factors on the divertor plasma solution and to make direct comparisons, most of the parameters including the meshes were kept as similar as possible. Only the neutral baffling was modified to compare a fully open divertor with a tightly closed one. The modeling shows that the tightly closed divertor greatly improves trapping of recycling neutrals, thereby increasing radiative and charge exchange losses in the divertor and reducing the electron temperature T et and deposited power density q dep at the target plate. Furthermore, the closed structure enables the divertor plasma to enter into highly dissipative and detached divertor conditions at a significantly lower upstream density. The effects of divertor closure on the neutral density and pressure, and their correlation with the divertor plasma conditions are also demonstrated. The effect of molecular D2-ion D+ elastic collisions and neutral-neutral collisions on the divertor plasma solution are assessed.
Numerical modelling of closed-cell aluminium foams under shock loading
NASA Astrophysics Data System (ADS)
Kader, M. A.; Islam, M. A.; Hazell, P. J.; Escobedo, J. P.; Saadatfar, M.; Brown, A. D.
2017-01-01
The present research numerically investigates shock propagation through closed-cell aluminium foam via flyer-plate impact. The mechanics of foam deformation was elucidated using the finite element (FE) software ABAQUS/explicit. X-ray computed micro-tomography was performed to render a full 3D foam geometry mesh for understanding detailed macrostructural response due to shock propagation. Elastic wave propagation and pore collapse mechanism with time were studied. The free surface velocity of the foam was measured at two different flyer-plate impact velocities to observe the profile of the shock wave with time. Good correlations were observed between experimental data and FE predictions for both test conditions.
NASA Astrophysics Data System (ADS)
Strokova, N. E.; Yagodovskaya, T. V.; Savilov, S. V.; Lukhovitskaya, E. E.; Vasil'ev, E. S.; Morozov, I. I.; Lunin, V. V.
2013-02-01
The reactions of ozone with chloroform and bromoform are studied using a flow gas discharge vacuum unit under conditions close to stratospheric (temperature range, 77-250 K; pressure, 10-3-0.1 Torr in the presence of nitrate ice). It is shown that the reaction with bromoform begins at 160 K; the reaction with chloroform, at 190 K. The reaction products are chlorine and bromine oxides of different composition, identified by low-temperature FTIR spectroscopy. The presence of nitrate ice raises the temperature of reaction onset to 210 K.
Closed-population capture-recapture modeling of samples drawn one at a time.
Barker, Richard J; Schofield, Matthew R; Wright, Janine A; Frantz, Alain C; Stevens, Chris
2014-12-01
Motivated by field sampling of DNA fragments, we describe a general model for capture-recapture modeling of samples drawn one at a time in continuous-time. Our model is based on Poisson sampling where the sampling time may be unobserved. We show that previously described models correspond to partial likelihoods from our Poisson model and their use may be justified through arguments concerning S- and Bayes-ancillarity of discarded information. We demonstrate a further link to continuous-time capture-recapture models and explain observations that have been made about this class of models in terms of partial ancillarity. We illustrate application of our models using data from the European badger (Meles meles) in which genotyping of DNA fragments was subject to error.
Climate and Integrated Assessment Modeling Studies Grant - Closed Announcement FY 2012
Grant to fund a cooperative agreement to benefit the field of economic and integrated assessment modeling related to climate change through regular collaborations and thedevelopment of model comparison studies.
NASA Technical Reports Server (NTRS)
Seufzer, William J.
2014-01-01
Additive manufacturing is coming into industrial use and has several desirable attributes. Control of the deposition remains a complex challenge, and so this literature review was initiated to capture current modeling efforts in the field of additive manufacturing. This paper summarizes about 10 years of modeling and simulation related to both welding and additive manufacturing. The goals were to learn who is doing what in modeling and simulation, to summarize various approaches taken to create models, and to identify research gaps. Later sections in the report summarize implications for closed-loop-control of the process, implications for local research efforts, and implications for local modeling efforts.
NASA Astrophysics Data System (ADS)
Hoffer, A.; Kiss, G.; Blazsó, M.; Gelencsér, A.
2004-03-01
A representative lignin-type component from biomass burning aerosol has been shown to react with OH radicals in model cloud water yielding colored organic species. In this paper we investigated the chemical properties of the complex reaction products formed from 3,5-dihydroxybenzoic acid. The reaction was followed by UV-VIS spectrophotometry, liquid chromatography, electrospray-mass spectrometry, thermally assisted hydrolysis and methylation-gas chromatography/mass spectrometry and a thermal method. This paper provides experimental proofs that actually larger molecular weight species are formed in the aqueous phase by free radical oligomerization. The features observed by all analytical techniques closely resemble those found for natural humic acids and HULIS found in rural and biomass burning aerosol. Therefore such processes are assumed to produce the ubiquitous humic-like substances (HULIS) in atmospheric aerosol. Since these species show intense absorbance in the lower visible to UV range, they might also be important in atmospheric absorption of solar radiation.
Modeling of finite amplitude acoustic waves in closed cavities using the Galerkin method.
Erickson, Robert R; Zinn, Ben T
2003-04-01
Nonlinear resonant gas oscillations in closed ducts are investigated by solving a previously derived, quasi-one-dimensional, nonlinear wave equation that accounts for forcing, gas dynamic nonlinearities, and viscous dissipation. This equation is solved with the approximate Galerkin method to determine the dependence of driven oscillations upon the duct shape, forcing frequency, and forcing amplitude. Initially, the applicability of the developed Galerkin solution approach was studied by investigating oscillations in a straight duct, closed at both ends and periodically oscillated at a single frequency. It is shown that the Galerkin method predictions of shock wave-like oscillations in such ducts are in excellent agreement with results obtained with other numerical solution techniques. Next, this study investigated the forced response of a class of horn-shaped ducts, and it is shown that for a given forcing amplitude, there exists a nonmonotonic increase in compression ratio as the duct's flare constant is increased. Finally, it is shown that oscillations driven in ducts whose shapes were chosen to provide shifting of the second and third natural acoustic mode frequencies exhibit significant waveform distortion and non-negligible increases in compression ratio when compared with oscillations driven in straight ducts.
Statistical mechanical model for a closed loop plectoneme with weak helix specific forces.
Lee, Dominic J O'
2017-04-12
We develop a statistical mechanical framework, based on a variational approximation, to describe closed loop plectonemes. This framework incorporates weak helix structure dependent forces into the determination of the free energy and average structure of a plectoneme. Notably, due to their chiral nature, helix structure dependent forces break the symmetry between left and right handed supercoiling. The theoretical approach, presented here, also provides a systematic way of enforcing the topological constraint of closed loop supercoiling in the variational approximation. At large plectoneme lengths, by considering correlation functions in an expansion in terms of the spatial mean twist density about its thermally averaged value, it can be argued that topological constraint may be approximated by replacing twist and writhe by their thermal averages. A Lagrange multiplier, containing the sum of average twist and writhe, can be added to the free energy to conveniently inforce this result. The average writhe can be calculated through the thermal average of the Gauss' integral in the variational approximation. Furthermore, this approach allows for a possible way to calculate finite size corrections due to the topological constraint. Using interaction energy terms from the mean-field Kornyshev-Leikin theory, for parameter values that correspond to weak helix dependent forces, we calculate the free energy, fluctuation magnitudes and mean geometric parameters for the plectoneme. We see a slight asymmetry, where interestingly, left handed supercoils have a looser structure than right handed ones, although with a lower free energy, unlike what the previous ground state calculations would suggest.
Statistical mechanical model for a closed loop plectoneme with weak helix specific forces
NASA Astrophysics Data System (ADS)
(O’ Lee, Dominic J.
2017-04-01
We develop a statistical mechanical framework, based on a variational approximation, to describe closed loop plectonemes. This framework incorporates weak helix structure dependent forces into the determination of the free energy and average structure of a plectoneme. Notably, due to their chiral nature, helix structure dependent forces break the symmetry between left and right handed supercoiling. The theoretical approach, presented here, also provides a systematic way of enforcing the topological constraint of closed loop supercoiling in the variational approximation. At large plectoneme lengths, by considering correlation functions in an expansion in terms of the spatial mean twist density about its thermally averaged value, it can be argued that topological constraint may be approximated by replacing twist and writhe by their thermal averages. A Lagrange multiplier, containing the sum of average twist and writhe, can be added to the free energy to conveniently inforce this result. The average writhe can be calculated through the thermal average of the Gauss’ integral in the variational approximation. Furthermore, this approach allows for a possible way to calculate finite size corrections due to the topological constraint. Using interaction energy terms from the mean-field Kornyshev–Leikin theory, for parameter values that correspond to weak helix dependent forces, we calculate the free energy, fluctuation magnitudes and mean geometric parameters for the plectoneme. We see a slight asymmetry, where interestingly, left handed supercoils have a looser structure than right handed ones, although with a lower free energy, unlike what the previous ground state calculations would suggest.
NASA Astrophysics Data System (ADS)
Kharin, Stanislav; Sarsengeldin, Merey; Kassabek, Samat
2016-08-01
We represent mathematical models of electromagnetic field dynamics and heat transfer in closed symmetric and asymmetric electrical contacts including Thomson effect, which are essentially nonlinear due to the dependence of thermal and electrical conductivities on temperature. Suggested solutions are based on the assumption of identity of equipotentials and isothermal surfaces, which agrees with experimental data and valid for both linear and nonlinear cases. Well known Kohlrausch temperature-potential relation is analytically justified.
NASA Astrophysics Data System (ADS)
López-Sanjuan, C.; Le Fèvre, O.; Tasca, L. A. M.; Epinat, B.; Amram, P.; Contini, T.; Garilli, B.; Kissler-Patig, M.; Moultaka, J.; Paioro, L.; Perret, V.; Queyrel, J.; Tresse, L.; Vergani, D.; Divoy, C.
2013-05-01
Context. The contribution of the merging process to the early phase of galaxy assembly at z > 1 and, in particular, to the build-up of the red sequence, still needs to be accurately assessed. Aims: We aim to measure the major merger rate of star-forming galaxies at 0.9 < z < 1.8, using close pairs identified from integral field spectroscopy (IFS). Methods: We use the velocity field maps obtained with SINFONI/VLT on the MASSIV sample, selected from the star-forming population in the VVDS. We identify physical pairs of galaxies from the measurement of the relative velocity and the projected separation (rp) of the galaxies in the pair. Using the well constrained selection function of the MASSIV sample, we derive at a mean redshift up to z = 1.54 the gas-rich major merger fraction (luminosity ratio μ = L2/L1 ≥ 1/4), and the gas-rich major merger rate using merger time scales from cosmological simulations. Results: We find a high gas-rich major merger fraction of 20.8+15.2-6.8%, 20.1+8.0-5.1%, and 22.0+13.7-7.3% for close pairs with rp ≤ 20 h-1 kpc in redshift ranges z = [0.94,1.06] , [1.2,1.5), and [1.5,1.8), respectively. This translates into a gas-rich major merger rate of 0.116+0.084-0.038 Gyr-1, 0.147+0.058-0.037 Gyr-1, and 0.127+0.079-0.042 Gyr-1 at z = 1.03,1.32, and 1.54, respectively. Combining our results with previous studies at z < 1, the gas-rich major merger rate evolves as (1 + z)n, with n = 3.95 ± 0.12, up to z = 1.5. From these results we infer that 35% of the star-forming galaxies with stellar masses overline{Mstar = 1010-1010.5 M⊙} = 1010 - 1010.5 M⊙ have undergone a major merger since z 1.5. We develop a simple model that shows that, assuming that all gas-rich major mergers lead to early-type galaxies, the combined effect of gas-rich and dry mergers is able to explain most of the evolution in the number density of massive early-type galaxies since z 1.5, with our measured gas-rich merger rate accounting for about two-thirds of this
Guley, Natalie H.; Rogers, Joshua T.; Del Mar, Nobel A.; Deng, Yunping; Islam, Rafiqul M.; D'Surney, Lauren; Ferrell, Jessica; Deng, Bowei; Hines-Beard, Jessica; Bu, Wei; Ren, Huiling; Elberger, Andrea J.; Marchetta, Jeffrey G.; Rex, Tonia S.; Honig, Marcia G.
2016-01-01
Abstract Mild traumatic brain injury (TBI) from focal head impact is the most common form of TBI in humans. Animal models, however, typically use direct impact to the exposed dura or skull, or blast to the entire head. We present a detailed characterization of a novel overpressure blast system to create focal closed-head mild TBI in mice. A high-pressure air pulse limited to a 7.5 mm diameter area on the left side of the head overlying the forebrain is delivered to anesthetized mice. The mouse eyes and ears are shielded, and its head and body are cushioned to minimize movement. This approach creates mild TBI by a pressure wave that acts on the brain, with minimal accompanying head acceleration-deceleration. A single 20-psi blast yields no functional deficits or brain injury, while a single 25–40 psi blast yields only slight motor deficits and brain damage. By contrast, a single 50–60 psi blast produces significant visual, motor, and neuropsychiatric impairments and axonal damage and microglial activation in major fiber tracts, but no contusive brain injury. This model thus reproduces the widespread axonal injury and functional impairments characteristic of closed-head mild TBI, without the complications of systemic or ocular blast effects or head acceleration that typically occur in other blast or impact models of closed-skull mild TBI. Accordingly, our model provides a simple way to examine the biomechanics, pathophysiology, and functional deficits that result from TBI and can serve as a reliable platform for testing therapies that reduce brain pathology and deficits. PMID:26414413
Guley, Natalie H; Rogers, Joshua T; Del Mar, Nobel A; Deng, Yunping; Islam, Rafiqul M; D'Surney, Lauren; Ferrell, Jessica; Deng, Bowei; Hines-Beard, Jessica; Bu, Wei; Ren, Huiling; Elberger, Andrea J; Marchetta, Jeffrey G; Rex, Tonia S; Honig, Marcia G; Reiner, Anton
2016-02-15
Mild traumatic brain injury (TBI) from focal head impact is the most common form of TBI in humans. Animal models, however, typically use direct impact to the exposed dura or skull, or blast to the entire head. We present a detailed characterization of a novel overpressure blast system to create focal closed-head mild TBI in mice. A high-pressure air pulse limited to a 7.5 mm diameter area on the left side of the head overlying the forebrain is delivered to anesthetized mice. The mouse eyes and ears are shielded, and its head and body are cushioned to minimize movement. This approach creates mild TBI by a pressure wave that acts on the brain, with minimal accompanying head acceleration-deceleration. A single 20-psi blast yields no functional deficits or brain injury, while a single 25-40 psi blast yields only slight motor deficits and brain damage. By contrast, a single 50-60 psi blast produces significant visual, motor, and neuropsychiatric impairments and axonal damage and microglial activation in major fiber tracts, but no contusive brain injury. This model thus reproduces the widespread axonal injury and functional impairments characteristic of closed-head mild TBI, without the complications of systemic or ocular blast effects or head acceleration that typically occur in other blast or impact models of closed-skull mild TBI. Accordingly, our model provides a simple way to examine the biomechanics, pathophysiology, and functional deficits that result from TBI and can serve as a reliable platform for testing therapies that reduce brain pathology and deficits.
Detailed Modeling of Distillation Technologies for Closed-Loop Water Recovery Systems
NASA Technical Reports Server (NTRS)
Allada, Rama Kumar; Lange, Kevin E.; Anderson, Molly S.
2011-01-01
Detailed chemical process simulations are a useful tool in designing and optimizing complex systems and architectures for human life support. Dynamic and steady-state models of these systems help contrast the interactions of various operating parameters and hardware designs, which become extremely useful in trade-study analyses. NASA?s Exploration Life Support technology development project recently made use of such models to compliment a series of tests on different waste water distillation systems. This paper presents efforts to develop chemical process simulations for three technologies: the Cascade Distillation System (CDS), the Vapor Compression Distillation (VCD) system and the Wiped-Film Rotating Disk (WFRD) using the Aspen Custom Modeler and Aspen Plus process simulation tools. The paper discusses system design, modeling details, and modeling results for each technology and presents some comparisons between the model results and recent test data. Following these initial comparisons, some general conclusions and forward work are discussed.
Dynamic Modeling of Process Technologies for Closed-Loop Water Recovery Systems
NASA Technical Reports Server (NTRS)
Allada, Rama Kumar; Lange, Kevin E.; Anderson, Molly S.
2012-01-01
Detailed chemical process simulations are a useful tool in designing and optimizing complex systems and architectures for human life support. Dynamic and steady-state models of these systems help contrast the interactions of various operating parameters and hardware designs, which become extremely useful in trade-study analyses. NASA s Exploration Life Support technology development project recently made use of such models to compliment a series of tests on different waste water distillation systems. This paper presents dynamic simulations of chemical process for primary processor technologies including: the Cascade Distillation System (CDS), the Vapor Compression Distillation (VCD) system, the Wiped-Film Rotating Disk (WFRD), and post-distillation water polishing processes such as the Volatiles Removal Assembly (VRA). These dynamic models were developed using the Aspen Custom Modeler (Registered TradeMark) and Aspen Plus(Registered TradeMark) process simulation tools. The results expand upon previous work for water recovery technology models and emphasize dynamic process modeling and results. The paper discusses system design, modeling details, and model results for each technology and presents some comparisons between the model results and available test data. Following these initial comparisons, some general conclusions and forward work are discussed.
Integrating Boolean Queries in Conjunctive Normal Form with Probabilistic Retrieval Models.
ERIC Educational Resources Information Center
Losee, Robert M.; Bookstein, Abraham
1988-01-01
Presents a model that places Boolean database queries into conjunctive normal form, thereby allowing probabilistic ranking of documents and the incorporation of relevance feedback. Experimental results compare the performance of a sequential learning probabilistic retrieval model with the proposed integrated Boolean probabilistic model and a fuzzy…
Dynamic Modeling of Process Technologies for Closed-Loop Water Recovery Systems
NASA Technical Reports Server (NTRS)
Allada, Rama Kumar; Lange, Kevin; Anderson, Molly
2011-01-01
Detailed chemical process simulations are a useful tool in designing and optimizing complex systems and architectures for human life support. Dynamic and steady-state models of these systems help contrast the interactions of various operating parameters and hardware designs, which become extremely useful in trade-study analyses. NASA s Exploration Life Support technology development project recently made use of such models to compliment a series of tests on different waste water distillation systems. This paper presents dynamic simulations of chemical process for primary processor technologies including: the Cascade Distillation System (CDS), the Vapor Compression Distillation (VCD) system, the Wiped-Film Rotating Disk (WFRD), and post-distillation water polishing processes such as the Volatiles Removal Assembly (VRA) that were developed using the Aspen Custom Modeler and Aspen Plus process simulation tools. The results expand upon previous work for water recovery technology models and emphasize dynamic process modeling and results. The paper discusses system design, modeling details, and model results for each technology and presents some comparisons between the model results and available test data. Following these initial comparisons, some general conclusions and forward work are discussed.
Bernal model - A simple equilibrium theory of close-packed liquids.
NASA Technical Reports Server (NTRS)
Caron, L. G.
1971-01-01
The Bernal model of a hard-sphere liquid is used in conjunction with an extension of the cell method to predict the behavior of liquid argon near melting. The entropy of disorder associated with the Bernal state is deduced. The model is found to be applicable to liquid metals.
Numerical field model simulation of full scale fire tests in a closed spherical/cylindrical vessel
NASA Astrophysics Data System (ADS)
Raycraft, Janet K.
1987-12-01
Most of the casualties incurred during a fire are due to the smoke generated. An understanding of the way smoke and fire spread during a fire would provide a valuable tool to save lives and minimize damage. The Naval Research Laboratory maintains a full scale test facility called Fire-1. The computer model developed in this thesis is based on the actual geometry of Fire-1 and uses field modeling. It is a three dimensional, finite difference model using primitive variables. The model includes local and global pressure corrections, surface radiation, turbulence, strong buoyancy, and conjugate boundary conditions. Given heat input data, the computer code produces pressure, temperature, density, and velocity fields. Experimental fire tests conducted in Fire-1 are used to validate the computer code. Reasonable agreement in the results has been found. Because of the model's ability to account for pressure, temperature and smoke buildup, its envisioned use is to predict fires aboard ships and submarines.
Tumour and normal tissue radiobiology in mouse models: how close are mice to mini-humans?
Koontz, Bridget F; Verhaegen, Frank; De Ruysscher, Dirk
2017-01-01
Animal modelling is essential to the study of radiobiology and the advancement of clinical radiation oncology by providing preclinical data. Mouse models in particular have been highly utilized in the study of both tumour and normal tissue radiobiology because of their cost effectiveness and versatility. Technology has significantly advanced in preclinical radiation techniques to allow highly conformal image-guided irradiation of small animals in an effort to mimic human treatment capabilities. However, the biological and physical limitations of animal modelling should be recognized and considered when interpreting preclinical radiotherapy (RT) studies. Murine tumour and normal tissue radioresponse has been shown to vary from human cellular and molecular pathways. Small animal irradiation techniques utilize different anatomical boundaries and may have different physical properties than human RT. This review addresses the difference between the human condition and mouse models and discusses possible strategies for future refinement of murine models of cancer and radiation for the benefit of both basic radiobiology and clinical translation.
12 CFR Appendix C to Part 717 - Model Forms for Opt-Out Notices
Code of Federal Regulations, 2014 CFR
2014-01-01
... FAIR CREDIT REPORTING Pt. 717, App. C Appendix C to Part 717—Model Forms for Opt-Out Notices a... marketing offers, contact us : • By telephone: 1-877-###-#### • On the Web: www.—.com • By mail: Check the... the Web: www.—.com • By mail: Check the box and complete the form below, and send the form to: _Do...
NASA Technical Reports Server (NTRS)
Bubsey, R. T.; Orange, T. W.; Pierce, W. S.; Shannon, J. L., Jr.
1992-01-01
A set of equations are presented describing certain fracture mechanics parameters for chevron notch bar and rod specimens. They are developed by fitting compliance calibration data reported earlier. The equations present the various parameters in their most useful forms. The data encompass the entire range of the specimen geometries most commonly used. Their use will facilitate the testing and analysis of brittle metals, ceramics, and glasses.
NASA Technical Reports Server (NTRS)
Birn, J.; Hones, E. W., Jr.; Craven, J. D.; Frank, L. A.; Elphinstone, R. D.; Stern, D. P.
1991-01-01
The boundary between open and closed field lines is investigated in the empirical Tsyganenko (1987) magnetic field model. All field lines extending to distances beyond -70 R(E), the tailward velocity limit of the Tsyganenko model are defined as open, while all other field lines, which cross the equatorial plane earthward of -70 R(E) and are connected with the earth at both ends, are assumed closed. It is found that this boundary at the surface of the earth, identified as the polar cap boundary, can exhibit the arrowhead shape, pointed toward the sun, which is found in horse collar auroras. For increasing activity levels, the polar cap increases in area and becomes rounder, so that the arrowhead shape is less pronounced. The presence of a net B(y) component can also lead to considerable rounding of the open flux region. The arrowhead shape is found to be closely associated with the increase of B(z) from the midnight region to the flanks of the tail, consistent with a similar increase of the plasma sheet thickness.
Modeling of Climate Change Mitigation, Impacts and Adaptation - Closed Announcement FY 2016
The Office of Atmospheric Programs is soliciting proposals to advance the field of climate economic modeling to assist decision makers and the public in effectively responding to the challenges and opportunities posed by climate change.
Form factors in quantum integrable models with GL(3)-invariant R-matrix
NASA Astrophysics Data System (ADS)
Pakuliak, S.; Ragoucy, E.; Slavnov, N. A.
2014-04-01
We study integrable models solvable by the nested algebraic Bethe ansatz and possessing GL(3)-invariant R-matrix. We obtain determinant representations for form factors of off-diagonal entries of the monodromy matrix. These representations can be used for the calculation of form factors and correlation functions of the XXX SU(3)-invariant Heisenberg chain.
12 CFR Appendix C to Part 222 - Model Forms for Opt-Out Notices
Code of Federal Regulations, 2010 CFR
2010-01-01
... SYSTEM FAIR CREDIT REPORTING (REGULATION V) Pt. 222, App. C Appendix C to Part 222—Model Forms for Opt...: 1-877-###-#### • On the Web: www.---.com • By mail: Check the box and complete the form below, and... limit marketing offers, contact us : • By telephone: 1-877-###-#### • On the Web: www.---.com • By...
12 CFR Appendix C to Part 222 - Model Forms for Opt-Out Notices
Code of Federal Regulations, 2014 CFR
2014-01-01
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12 CFR Appendix C to Part 222 - Model Forms for Opt-Out Notices
Code of Federal Regulations, 2013 CFR
2013-01-01
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25 CFR 162.302 - Is there a model residential lease form?
Code of Federal Regulations, 2014 CFR
2014-04-01
... of Housing and Urban Development, the Department of Veterans' Affairs, and the Department of Agriculture. Use of a model lease form is not mandatory, provided all requirements of this part are met....
Fan, Senqing; Chen, Shiping; Tang, Xiaoyu; Xiao, Zeyi; Deng, Qing; Yao, Peina; Sun, Zhaopeng; Zhang, Yan; Chen, Chunyan
2015-02-01
Unstructured kinetic models were proposed to describe the principal kinetics involved in ethanol fermentation in a continuous and closed-circulating fermentation (CCCF) process with a pervaporation membrane bioreactor. After ethanol was removed in situ from the broth by the membrane pervaporation, the secondary metabolites accumulated in the broth became the inhibitors to cell growth. The cell death rate related to the deterioration of the culture environment was described as a function of the cell concentration and fermentation time. In CCCF process, 609.8 g L(-1) and 750.1 g L(-1) of ethanol production were obtained in the first run and second run, respectively. The modified Gompertz model, correlating the ethanol production with the fermentation period, could be used to describe the ethanol production during CCCF process. The fitting results by the models showed good agreement with the experimental data. These models could be employed for the CCCF process technology development for ethanol fermentation.
NASA Astrophysics Data System (ADS)
Kohler, Susanna
2016-09-01
Weve recently discovered narrow sets of rings around two minor planets orbiting in our solar system. How did these rings form? A new study shows that they could be a result of close encounters between the minor planets and giants like Jupiter or Neptune.Unexpected Ring SystemsPositions of the centaurs in our solar system (green). Giant planets (red), Jupiter trojans (grey), scattered disk objects (tan) and Kuiper belt objects (blue) are also shown. [WilyD]Centaurs are minor planets in our solar system that orbit between Jupiter and Neptune. These bodies of which there are roughly 44,000 with diameters larger than 1 km have dynamically unstable orbits that cross paths with those of one or more giant planets.Recent occultation observations of two centaurs, 10199 Chariklo and 2060 Chiron, revealed that these bodies both host narrow ring systems. Besides our four giant planets, Chariklo and Chiron are the only other bodies in the solar system known to have rings. But how did these rings form?Scientists have proposed several models, implicating collisions, disruption of a primordial satellite, or dusty outgassing. But a team of scientists led by Ryuki Hyodo (Paris Institute of Earth Physics, Kobe University) has recently proposed an alternative scenario: what if the rings were formed from partial disruption of the centaur itself, after it crossed just a little too close to a giant planet?Tidal Forces from a GiantHyodo and collaborators first used past studies of centaur orbits to estimate that roughly 10% of centaurs experience close encounters (passing within a distance of ~2x the planetary radius) with a giant planet during their million-year lifetime. The team then performed a series of simulations of close encounters between a giant planet and a differentiated centaur a body in which the rocky material has sunk to form a dense silicate core, surrounded by an icy mantle.Some snapshots of simulation outcomes (click for a closer look!) for different initial states of
NASA Astrophysics Data System (ADS)
GASPARETTO, A.
2001-02-01
Vibration control of flexible link mechanisms with more than two flexible links is still an open question, mainly because defining a model that is adequate for the designing of a controller is a rather difficult task. In this work, an accurate dynamic non-linear model of a flexible-link planar mechanism is presented. In order to bring the system into a form that is suitable for the design of a vibration controller, the model is then linearized about an operating point, so as to achieve a linear model of the system in the standard state-space form of system theory. The linear model obtained, which is valid for whatever planar mechanism with any number of flexible link, is then applied to a four-bar planar linkage. Extensive simulation is carried out, aimed at comparing the system dynamic evolution, both in the open- and in the closed-loop case, using the non-linear model and the linearized one. The results prove that the error made by using the linearized system instead of the non-linear one is small. Therefore, it can be concluded that the model proposed in this work can constitute an effective basis for designing and testing many types of vibration controllers for flexible planar mechanisms.
A crude model to study radio frequency induced density modification close to launchers
Van Eester, Dirk; Crombé, Kristel
2015-12-15
The interplay between radio frequency (RF) waves and the density is discussed by adopting the general framework of a 2-time-scale multi-fluid treatment, allowing to separate the dynamics on the RF time scale from that on the time scale on which macroscopic density and flows vary as a result of the presence of electromagnetic and/or electrostatic fields. The focus is on regions close to launchers where charge neutrality is incomplete and waves are commonly evanescent. The fast time scale dynamics influences the slow time scale behavior via quasilinear terms (the Ponderomotive force for the case of the equation of motion). Electrons and ions are treated on the same footing. Also, both fast and slow waves are retained in the wave description. Although this work is meant as a subtopic of a large study—the wave induced “convective cell” physics at hand is of a 2- or 3-dimensional nature while this paper limits itself to a single dimension—a few tentative examples are presented.