Science.gov

Sample records for closed form model

  1. 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.

  2. 12 CFR Appendix H to Part 1026 - Closed-End Model Forms and Clauses

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 8 2012-01-01 2012-01-01 false Closed-End Model Forms and Clauses H Appendix H...) 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) H-3Amount Financed Itemization Model Form (§ 1026.18(c))...

  3. 12 CFR Appendix H to Part 1026 - Closed-End Model Forms and Clauses

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 8 2013-01-01 2013-01-01 false Closed-End Model Forms and Clauses H Appendix H...) 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) H-3Amount Financed Itemization Model Form (§ 1026.18(c))...

  4. 12 CFR Appendix H to Part 226 - Closed-End Model Forms and Clauses

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 3 2010-01-01 2010-01-01 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 Model Forms and Clauses H-1—Credit Sale Model Form (§ 226.18) H-2—Loan Model Form (§ 226.18)...

  5. 12 CFR Appendix H to Part 226 - Closed-End Model Forms and Clauses

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 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 Model Forms and Clauses H-1Credit Sale Model Form (§ 226.18) H-2Loan Model Form (§ 226.18) H-3Amount...

  6. 12 CFR Appendix H to Part 226 - Closed-End Model Forms and Clauses

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 3 2012-01-01 2012-01-01 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 Model Forms and Clauses H-1Credit Sale Model Form (§ 226.18) H-2Loan Model Form (§ 226.18) H-3Amount...

  7. 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)...

  8. 12 CFR Appendix H to Part 226 - Closed-End Model Forms and Clauses

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 3 2014-01-01 2014-01-01 false Closed-End Model Forms and Clauses H Appendix H...-End Model Forms and Clauses H-1 Credit Sale Model Form (§ 226.18) H-2 Loan Model Form (§ 226.18) H-3 Amount Financed Itemization Model Form (§ 226.18(c)) H-4(A) Variable-Rate Model Clauses (§...

  9. NLOS UV channel modeling using numerical integration and an approximate closed-form path loss model

    NASA Astrophysics Data System (ADS)

    Gupta, Ankit; Noshad, Mohammad; Brandt-Pearce, Maïté

    2012-10-01

    In this paper we propose a simulation method using numerical integration, and develop a closed-form link loss model for physical layer channel characterization for non-line of sight (NLOS) ultraviolet (UV) communication systems. The impulse response of the channel is calculated by assuming both uniform and Gaussian profiles for transmitted beams and different geometries. The results are compared with previously published results. The accuracy of the integration approach is compared to the Monte Carlo simulation. Then the path loss using the simulation method and the suggested closed-form expression are presented for different link geometries. The accuracies are evaluated and compared to the results obtained using other methods.

  10. Implementation and identification of Preisach type hysteresis models with Everett Function in closed form

    NASA Astrophysics Data System (ADS)

    Szabó, Zsolt; Füzi, János

    2016-05-01

    The Preisach function is considered as a product of two special one dimensional functions, which allows the closed form evaluation of the Everett integral. The deduced closed form expressions are included in Preisach models, in particular in the static model, moving model and a rate dependent hysteresis model, which can simulate the frequency dependence of the magnetization process. The details of the freely available implementations, which are available online are presented. The identification of the model parameters and the accuracy to describe the magnetization process are discussed and demonstrated by fitting measured data. Transient electric circuit simulation with hysteresis demonstrates the applicability of the developed models.

  11. Closed-form impulse response model of non-line-of-sight single-scatter propagation.

    PubMed

    Sun, Yu; Zhan, Yafeng

    2016-04-01

    For optical scattering communication, a closed-form expression of channel impulse response (CIR) is favorable for further system design and channel capacity analysis. Combining the mean value theorem of integrals and L'Hôpital's rule, the exact non-line-of-sight (NLOS) single-scatter propagation model is simplified to a closed-form CIR model for a laser source with a narrow beam. Based on this model, by joint geometrical and empirical approaches, a piecewise CIR expression is presented under certain system NLOS geometries. Through numerical results on CIR for various NLOS geometries, the proposed model is verified with the exact NLOS single-scatter propagation model and the previous Gamma fitting model, showing that our model agrees better with the former than the latter. PMID:27140787

  12. 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.

  13. A closed-form capacitance model for tunnel FETs with explicit surface potential solutions

    NASA Astrophysics Data System (ADS)

    Wang, Jiaxin; Wu, Chunlei; Huang, Qianqian; Wang, Chao; Huang, Ru

    2014-09-01

    In this paper, a closed-form physical capacitance model for bulk tunnel FETs (TFETs) is proposed based on the surface potential approach for the first time. Fundamentally different from that in the MOSFET, the channel surface potential φsf in the TFET is alternately controlled by the drain bias and gate bias in different operation regions. On the basis of physical insight into the operation mechanism, the analytical model of φsf as a function of terminal bias is established. The Gaussian box is introduced to predict the surface potential profile near the source-body junction. Furthermore, the surface-potential-based capacitance model is derived and the calculated terminal capacitances show good agreement with the TCAD simulation results. With the essential physics considered, excellent validity of the model is achieved for bulk TFETs with a large range of structure parameters and SOI/double-gate (DG) TFETs.

  14. A mass weighted chemical elastic network model elucidates closed form domain motions in proteins

    PubMed Central

    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

  15. Closed form solution of the itinerant oscillator model of molecular libration

    NASA Astrophysics Data System (ADS)

    Coffey, W. T.; Walsh, M. E.

    1997-05-01

    It is shown by using self-consistent (so that action and reaction torques are fully accounted for) expressions for the viscous drag and white noise terms in the equations of motion of the fixed axis rotator version of the itinerant oscillator model that the characteristic (secular) equation of the system automatically factorizes. Hence all the correlation functions of the model (which consists of a "cage" of dipolar molecules surrounding a tagged molecule) may be given in closed form. In particular, the orientational correlation functions of the tagged molecule become the products of single particle ones namely those of a free Brownian rotator and a damped harmonic oscillator while the orientational correlation functions of the cage are simply those of the free Brownian rotator. The equations of motion of the system likewise decouple when the restrictions of small oscillations and of rotation about a fixed axis are removed. Thus, irrespective of the form of the interaction potential between the cage and the tagged molecule, the relaxation modes of the system separate into those of the tagged molecule and those of its surroundings which behave as an inertia corrected free Brownian rotator.

  16. An approximate closed-form link loss model for non-line-of-sight ultraviolet communication in noncoplanar geometry.

    PubMed

    Wang, Leijie; Xu, Zhengyuan; Sadler, Brian M

    2011-04-01

    Non-line-of-sight UV communication link path loss models have been explored for both coplanar and noncoplanar geometries, and these typically require numerical evaluation. In this Letter, we propose a closed-form and easily applied model to describe link behavior, applicable to noncoplanar geometry. The model is compared with a recently reported analytical model and shows good agreement. PMID:21479037

  17. 12 CFR Appendix H to Part 226 - Closed-End Model Forms and Clauses

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... RESERVE SYSTEM (CONTINUED) TRUTH IN LENDING (REGULATION Z) Pt. 226, App. H Appendix H to Part 226— Closed... Summary Model Clause (§ 226.18(s)) H-4(F)—Adjustable-Rate Mortgage or Step-Rate Mortgage Interest Rate and Payment Summary Model Clause (§ 226.18(s)) H-4(G)—Mortgage with Negative Amortization Interest Rate...

  18. 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.

  19. A numerical model based on closed form solution for elastic stability of thin plates

    NASA Astrophysics Data System (ADS)

    Ciaramella, S.; Migliore, M.; Minutolo, V.; Ruocco, E.

    2010-06-01

    An analytical approach for studying the elastic stability of thin rectangular plates under arbitrary boundary conditions is presented. Because the solution is given in closed-form, the approach can be regarded as "exact" under the Kirchhoff-Love assumption. The proposed procedure allows us to obtain the buckling load and modal displacements that do not depend on the number of elements adopted in the numerical discretization using, say, the finite element method.

  20. Closed-form path loss model of non-line-of-sight ultraviolet single-scatter propagation.

    PubMed

    Zuo, Yong; Xiao, Houfei; Wu, Jian; Li, Wei; Lin, Jintong

    2013-06-15

    Non-line-of-sight ultraviolet propagation models have been developed for both coplanar and noncoplanar geometries. Based on an exact integral-form single-scatter model, this Letter proposes an approximate closed-form model for tractable analysis applicable to noncoplanar geometries with a narrow transmitter beam or receiver field of view. Numerical results on path loss are presented for various system geometries. These results are verified with the integral-form model and a previous approximate model, showing our model agrees well with the former and outperforms the latter. PMID:23938995

  1. Path integral approach to closed-form option pricing formulas with applications to stochastic volatility and interest rate models

    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.

  2. On the random-based closed-cell metal foam modeling and its behavior in laser forming process

    NASA Astrophysics Data System (ADS)

    Roohi, Amir H.; Naeini, H. Moslemi; Gollo, M. Hoseinpour; Soltanpour, M.; Abbaszadeh, M.

    2015-09-01

    Metal foams are a new material category that, in the recent decade, are excessively used because of their good physical and mechanical properties such as low density and high stiffness. Regarding to their importance in engineering and other applications, modeling of metal foams are being studied and limited investigations have been carried out. The aim of this study is to develop a novel method to model the closed-cell metal foams. Closer modeling of foam sheets, which has an amorphous structure, are achieved by subtracting spheres with a random spatial position and random radius from an initial sheet rather than repeating a unit cell. In this article, the geometric properties of the closed-cell model is compared with the real foam. Also, finite element analysis of the laser forming process of the modeled foam is carried out. The effects of three geometrical parameters on bending angle is investigated. Both geometric comparison and FE validation shows a close agreement between numerical and actual results. Results show that relative density of the foam has the most effect and the mean cell size has the least effect on final bending angle.

  3. Fourier domain closed-form formulas for estimation of kinetic parameters in reversible multi-compartment models

    PubMed Central

    2012-01-01

    Background Compared with static imaging, dynamic emission computed tomographic imaging with compartment modeling can quantify in vivo physiologic processes, providing useful information about molecular disease processes. Dynamic imaging involves estimation of kinetic rate parameters. For multi-compartment models, kinetic parameter estimation can be computationally demanding and problematic with local minima. Methods This paper offers a new perspective to the compartment model fitting problem where Fourier linear system theory is applied to derive closed-form formulas for estimating kinetic parameters for the two-compartment model. The proposed Fourier domain estimation method provides a unique solution, and offers very different noise response as compared to traditional non-linear chi-squared minimization techniques. Results The unique feature of the proposed Fourier domain method is that only low frequency components are used for kinetic parameter estimation, where the DC (i.e., the zero frequency) component in the data is treated as the most important information, and high frequency components that tend to be corrupted by statistical noise are discarded. Computer simulations show that the proposed method is robust without having to specify the initial condition. The resultant solution can be fine tuned using the traditional iterative method. Conclusions The proposed Fourier-domain estimation method has closed-form formulas. The proposed Fourier-domain curve-fitting method does not require an initial condition, it minimizes a quadratic objective function and a closed-form solution can be obtained. The noise is easier to control, simply by discarding the high frequency components, and emphasizing the DC component. PMID:22995548

  4. Non-dimensionalised closed-form parametric analysis of semi-active vehicle suspensions using a quarter-car model

    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.

  5. A copula-based closed-form binary logit choice model for accommodating spatial correlation across observational units

    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.

  6. Exact model reduction with delays: closed-form distributions and extensions to fully bi-directional monomolecular reactions

    PubMed Central

    Leier, Andre; Barrio, Manuel; Marquez-Lago, Tatiana T.

    2014-01-01

    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. PMID:24694895

  7. Close-Call Action Log Form

    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.

  8. Optimal Mortgage Refinancing: A Closed Form Solution

    PubMed Central

    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

  9. Closed-form formulas for the effective properties of random particulate nanocomposites with complete Gurtin-Murdoch model of material surfaces

    NASA Astrophysics Data System (ADS)

    Nazarenko, Lidiia; Bargmann, Swantje; Stolarski, Henryk

    2016-07-01

    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.

  10. Closed-form analytical model of static noise margin for ultra-low voltage eight-transistor tunnel FET static random access memory

    NASA Astrophysics Data System (ADS)

    Fuketa, Hiroshi; O'uchi, Shin-ichi; Fukuda, Koichi; Mori, Takahiro; Morita, Yukinori; Masahara, Meishoku; Matsukawa, Takashi

    2016-04-01

    Variations of eight-transistor (8T) tunnel FET (TFET) static random access memory (SRAM) cells at ultra-low supply voltage (V DD) of 0.3 V are discussed. A closed-form analytical model for the static noise margin (SNM) of the TFET SRAM cells is proposed to clarify the dependence of SNM on device parameters and is verified by simulations. The SNM variations caused by process variations are investigated using the proposed model, and we show a requirement for the threshold voltage (V TH) variation in the TFET SRAM design, which indicates that the V TH variation must be reduced as the subthreshold swing becomes steeper. In addition, a feasibility of the TFET SRAM cells operating at V DD = 0.3 V in two different process technologies is evaluated using the proposed model.

  11. Closed-form inverse kinematics for interventional C-arm X-ray imaging with six degrees of freedom: modeling and application.

    PubMed

    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). PMID:22293978

  12. 46 CFR 308.533 - Closing report, Form MA-313.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 8 2011-10-01 2011-10-01 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 Ii-Open Policy War Risk Cargo Insurance § 308.533 Closing report, Form...

  13. 46 CFR 308.533 - Closing report, Form MA-313.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 8 2012-10-01 2012-10-01 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 Ii-Open Policy War Risk Cargo Insurance § 308.533 Closing report, Form...

  14. 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....

  15. 46 CFR 308.533 - Closing report, Form MA-313.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 8 2013-10-01 2013-10-01 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 Ii-Open Policy War Risk Cargo Insurance § 308.533 Closing report, Form...

  16. A New Closed-Form Information Metric for Shape Analysis

    PubMed Central

    Peter, Adrian; Rangarajan, Anand

    2010-01-01

    Shape matching plays a prominent role in the analysis of medical and biological structures. Recently, a unifying framework was introduced for shape matching that uses mixture-models to couple both the shape representation and deformation. Essentially, shape distances were defined as geodesics induced by the Fisher-Rao metric on the manifold of mixture-model represented shapes. A fundamental drawback of the Fisher-Rao metric is that it is NOT available in closed-form for the mixture model. Consequently, shape comparisons are computationally very expensive. Here, we propose a new Riemannian metric based on generalized ϕ- entropy measures. In sharp contrast to the Fisher-Rao metric, our new metric is available in closed-form. Geodesic computations using the new metric are considerably more efficient. Discriminative capabilities of this new metric are studied by pairwise matching of corpus callosum shapes. Comparisons are conducted with the Fisher-Rao metric and the thin-plate spline bending energy. PMID:17354897

  17. 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.

  18. Explicit Closed Forms for Parametric Integrals. Classroom Notes

    ERIC Educational Resources Information Center

    Dana-Picard, Thierry

    2004-01-01

    Closed forms are computed for parametric integrals, generally using induction formulas. It is shown that these integrals can be core activities, mixing hand-work, computations with a computer algebra system and experimental mathematics with an interactive website.

  19. Closed form evaluation of symmetric two-sided complex integrals

    NASA Technical Reports Server (NTRS)

    Winkelstein, R.

    1981-01-01

    Evaluation of two-sided complex integrals is often required when analyzing linear systems to determine signal variances resulting from stochastic inputs and system noise bandwidths. Algebraic solutions of integrals in a closed matrix equation form, using coefficients of the numerator and denominator polynomials, are presented. The closed forms provide the possibility of obtaining some insight into parameter sensitivity in addition to greatly reducing the computational complexity required by the normal method of evaluation by residues.

  20. 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.

  1. A Systematic Approach for Multidimensional, Closed-Form Analytic Modeling: Effective Intrinsic Carrier Concentrations in Ga 1-x Al x As Heterostructures.

    PubMed

    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- x Al x As, 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- x Al x As as functions of the mole fraction x of AlAs between 0.0 and 0.3. In these calculations, the donor density N D for n-type material varies between 10(16) cm(-3) and 10(19) cm(-3) and the acceptor density N A for p-type materials varies between 10(16) cm(-3) and 10(20) cm(-3). We find that p-type Ga1- x Al x As 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- x Al x As 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

  2. A Systematic Approach for Multidimensional, Closed-Form Analytic Modeling: Effective Intrinsic Carrier Concentrations in Ga1−xAlxAs Heterostructures

    PubMed Central

    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

  3. 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...

  4. Single-spin precessing gravitational waveform in closed form

    NASA Astrophysics Data System (ADS)

    Lundgren, Andrew; O'Shaughnessy, R.

    2014-02-01

    In coming years, gravitational-wave detectors should find black hole-neutron star (BH-NS) binaries, potentially coincident with astronomical phenomena like short gamma ray bursts. These binaries are expected to precess. Gravitational-wave science requires a tractable model for precessing binaries, to disentangle precession physics from other phenomena like modified strong field gravity, tidal deformability, or Hubble flow; and to measure compact object masses, spins, and alignments. Moreover, current searches for gravitational waves from compact binaries use templates where the binary does not precess and are ill-suited for detection of generic precessing sources. In this paper we provide a closed-form representation of the single-spin precessing waveform in the frequency domain by reorganizing the signal as a sum over harmonics, each of which resembles a nonprecessing waveform. This form enables simple analytic calculations of the Fisher matrix for use in template bank generation and coincidence metrics, and jump proposals to improve the efficiency of Markov chain Monte Carlo sampling. We have verified that for generic BH-NS binaries, our model agrees with the time-domain waveform to 2%. Straightforward extensions of the derivations outlined here (and provided in full online) allow higher accuracy and error estimates.

  5. Cluster speckle structures through multiple apertures forming a closed curve

    NASA Astrophysics Data System (ADS)

    Mosso, E.; Tebaldi, M.; Lencina, A.; Bolognini, N.

    2010-04-01

    In this work, cluster-like speckle patterns are analyzed. These patterns are generated when a diffuser illuminated by coherent light is imaged by a lens having a pupil mask with multiple apertures forming a closed curve. We show that the cluster structure results from the complex modulation produced inside each speckle which is generated by multiple interferences of light through the apertures. In particular, when the apertures are uniformly distributed along a closed curve, the resulting image speckle cluster replicates the pupil aperture distribution. Experimental results and theoretical simulations show that cluster features depend on the apertures distribution and the size of the closed curves.

  6. Closed-form analysis for elastic deformations of multilayered strands

    NASA Technical Reports Server (NTRS)

    Kumar, K.; Cochran, J. E., Jr.

    1987-01-01

    Closed-form solutions are developed for elastic deformation characteristics of multilayered strands under tensile and torsional loads. These analytical results are successfully applied to obtain expressions for the effective extensional and torsional moduli of rigidity for the strands. Finally, a simple design criterion is established for 'nonrotating' cables.

  7. Modeling of closed membrane shapes

    NASA Astrophysics Data System (ADS)

    Penič, S.; Mesarec, L.; Fošnarič, M.; Kralj Iglič, V.; Kralj, S.; Góźdź, W.; Iglič, A.

    2014-12-01

    Closed biological membranes were considered within the spontaneous curvature model. Ground state membrane shapes were compared with Monte Carlo simulations in the thermal equilibrium, where membranes are subject to thermal fluctuations. The results of the two approaches correspond well with each other. The oblate discocyte membrane shapes are obtained in the ground state but can become metastable when thermal fluctuations are taken into account. The nematic ordering in oblate and stomatocyte vesicle membranes was also studied. It was confirmed that the net topological charge on the surfaces with the topology of a sphere was 2. On the oblate vesicle four topological defects, each with charge 1/2, assembled in the region exhibiting the highest Gaussian curvature. On the stomatocyte vesicle with six topological defects, each with charge 1/2, and two topological antidefects, each with charge -1/2, the latter assembled in the region with a negative Gaussian curvature. The position of topological defects is strongly curvature dependent.

  8. Closed-form summations of Dowker's and related trigonometric sums

    NASA Astrophysics Data System (ADS)

    Cvijović, Djurdje; Srivastava, H. M.

    2012-09-01

    Through a unified and relatively simple approach which uses complex contour integrals, particularly convenient integration contours and calculus of residues, closed-form summation formulas for 12 very general families of trigonometric sums are deduced. One of them is a family of cosecant sums which was first summed in closed form in a series of papers by Dowker (1987 Phys. Rev. D 36 3095-101 1989 J. Math. Phys. 30 770-3 1992 J. Phys. A: Math. Gen. 25 2641-8), whose method has inspired our work in this area. All of the formulas derived here involve the higher-order Bernoulli polynomials. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical in honour of Stuart Dowker's 75th birthday devoted to ‘Applications of zeta functions and other spectral functions in mathematics and physics’.

  9. 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

  10. 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…

  11. Jet-boundary and Plan-form Corrections for Partial-Span Models with Reflection-Plane, End-Plate, or No End-Plate in a Closed Circular Wind Tunnel

    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.

  12. 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.

  13. Form 5-Mining venture agreement model form

    SciTech Connect

    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.

  14. Delay chemical master equation: direct and closed-form solutions

    PubMed Central

    Leier, Andre; Marquez-Lago, Tatiana T.

    2015-01-01

    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. PMID:26345616

  15. Stresses in adhesively bonded joints - A closed-form solution

    NASA Technical Reports Server (NTRS)

    Delale, F.; Erdogan, F.; Aydinoglu, M. N.

    1981-01-01

    The general plane strain problem of adhesively bonded structures consisting of two different, orthotropic adherends is considered, under the assumption that adherend thicknesses are constant and small in relation to the lateral dimensions of the bonded region, so that they may be treated as plates. The problem is reduced to a system of differential equations for the adhesive stresses which is solved in closed form, with a single lap joint and a stiffened plate under various loading conditions being considered as examples. It is found that the plate theory used in the analysis not only predicts the correct trend for adhesive stresses but gives surprisingly accurate results, the solution being obtained by assuming linear stress-strain relations for the adhesive.

  16. 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. 46 CFR 308.534 - Certificate to be attached to closing report, Form MA-313-A.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 8 2012-10-01 2012-10-01 false Certificate to be attached to closing report, Form MA... § 308.534 Certificate to be attached to closing report, Form MA-313-A. The standard form of Certificate to be attached to the closing report, Form MA-313-A, may be obtained from the American War...

  18. 46 CFR 308.534 - Certificate to be attached to closing report, Form MA-313-A.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 8 2011-10-01 2011-10-01 false Certificate to be attached to closing report, Form MA... § 308.534 Certificate to be attached to closing report, Form MA-313-A. The standard form of Certificate to be attached to the closing report, Form MA-313-A, may be obtained from the American War...

  19. 46 CFR 308.534 - Certificate to be attached to closing report, Form MA-313-A.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 8 2013-10-01 2013-10-01 false Certificate to be attached to closing report, Form MA... § 308.534 Certificate to be attached to closing report, Form MA-313-A. The standard form of Certificate to be attached to the closing report, Form MA-313-A, may be obtained from the American War...

  20. 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....534 Certificate to be attached to closing report, Form MA-313-A. The standard form of Certificate to be attached to the closing report, Form MA-313-A, may be obtained from MARAD's underwriting agent...

  1. Cosmic ray antiprotons in closed galaxy model

    NASA Technical Reports Server (NTRS)

    Protheroe, R.

    1981-01-01

    The flux of secondary antiprotons expected for the leaky-box model was calculated as well as that for the closed galaxy model of Peters and Westergard (1977). The antiproton/proton ratio observed at several GeV is a factor of 4 higher than the prediction for the leaky-box model but is consistent with that predicted for the closed galaxy model. New low energy data is not consistent with either model. The possibility of a primary antiproton component is discussed.

  2. path integral approach to closed form pricing formulas in the Heston framework.

    NASA Astrophysics Data System (ADS)

    Lemmens, Damiaan; Wouters, Michiel; Tempere, Jacques; Foulon, Sven

    2008-03-01

    We present a path integral approach for finding closed form formulas for option prices in the framework of the Heston model. The first model for determining option prices was the Black-Scholes model, which assumed that the logreturn followed a Wiener process with a given drift and constant volatility. To provide a realistic description of the market, the Black-Scholes results must be extended to include stochastic volatility. This is achieved by the Heston model, which assumes that the volatility follows a mean reverting square root process. Current applications of the Heston model are hampered by the unavailability of fast numerical methods, due to a lack of closed-form formulae. Therefore the search for closed form solutions is an essential step before the qualitatively better stochastic volatility models will be used in practice. To attain this goal we outline a simplified path integral approach yielding straightforward results for vanilla Heston options with correlation. Extensions to barrier options and other path-dependent option are discussed, and the new derivation is compared to existing results obtained from alternative path-integral approaches (Dragulescu, Kleinert).

  3. 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.

  4. Looking Closely at ``Medusa": Star Forming Regions in NGC 4194

    NASA Astrophysics Data System (ADS)

    Weistrop, D.; Eggers, D.; Nelson, C. H.; Kaiser, M. E.

    2000-05-01

    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 (Kinney, et al. 1993). Malkan et al.'s (1998) HST survey of Seyfert and starburst galaxies notes NGC 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 sizes 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. This work has been supported in part by NASA, under contract NAS5-31231.

  5. Closed-Form Two-Locus Sampling Distributions: Accuracy and Universality

    PubMed Central

    Jenkins, Paul A.; Song, Yun S.

    2009-01-01

    Sampling distributions play an important role in population genetics analyses, but closed-form sampling formulas are generally intractable to obtain. In the presence of recombination, there is no known closed-form sampling formula that holds for an arbitrary recombination rate. However, we recently showed that it is possible to obtain useful closed-form sampling formulas when the population-scaled recombination rate ρ is large. Specifically, in the case of the two-locus infinite-alleles model, we considered an asymptotic expansion of the sampling formula in inverse powers of ρ and obtained closed-form expressions for the first few terms in the expansion. In this article, we generalize this result to an arbitrary finite-alleles mutation model and show that, up to the first few terms in the expansion that we are able to compute analytically, the functional form of the asymptotic sampling formula is common to all mutation models. We carry out an extensive study of the accuracy of the asymptotic formula for the two-locus parent-independent mutation model and discuss in detail a concrete application in the context of the composite-likelihood method. Furthermore, using our asymptotic sampling formula, we establish a simple sufficient condition for a given two-locus sample configuration to have a finite maximum-likelihood estimate (MLE) of ρ. This condition is the first analytic result on the classification of the MLE of ρ and is instantaneous to check in practice, provided that one-locus probabilities are known. PMID:19737744

  6. Mathematical modeling relevant to closed artificial ecosystems

    USGS Publications Warehouse

    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.

  7. Reverse Engineering of Free-Form Surface Based on the Closed-Loop Theory

    PubMed Central

    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. PMID:25879078

  8. Photochemistry of benzylallene: ring-closing reactions to form naphthalene.

    PubMed

    Sebree, Joshua A; Kidwell, Nathanael M; Selby, Talitha M; Amberger, Brent K; McMahon, Robert J; Zwier, Timothy S

    2012-01-18

    Conformer-specific, vibrationally resolved electronic spectroscopy of benzylallene (4-phenyl-1,2-butadiene) is presented along with a detailed analysis of the products formed via its ultraviolet photoexcitation. Benzylallene is the minor product of the recombination of benzyl and propargyl radicals. The mass-selective resonant two-photon ionization spectrum of benzylallene was recorded under jet-cooled conditions, with its S(0)-S(1) origin at 37,483 cm(-1). UV-UV holeburning spectroscopy was used to show that only one conformer was present in the expansion. Rotational band contour analysis provided rotational constants and transition dipole moment direction consistent with a conformation in which the allene side chain is in the anti position, pointing away from the phenyl ring. The photochemistry of benzylallene was studied in a pump-probe geometry in which photoexcitation occurred by counter-propagating the expansion with a photoexcitation laser. The laser was timed to interact with the gas pulse in a short tube that extended the collisional region of the expansion. The products were cooled during expansion of the gas mixture into vacuum, before being interrogated using mass-selective resonant two-photon ionization. The UV-vis spectra of the photochemical products were compared to literature spectra for identification. Several wavelengths were chosen for photoexcitation, ranging from the S(0)-S(1) origin transition (266.79 nm) to 193 nm. Comparison of the product spectral intensities as a function of photoexcitation wavelength provides information on the wavelength dependence of the product yields. Photoexcitation at 266.79 nm yielded five products (benzyl radical, benzylallenyl radical, 1-phenyl-1,3-butadiene, 1,2-dihydronaphthalene, and naphthalene), with naphthalene and benzylallenyl radicals dominant. At 193 nm, the benzylallenyl radical signal was greatly reduced in intensity, while three additional C(10)H(8) isomeric products were observed. An extensive set

  9. 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.

  10. 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.

  11. Resolving the biophysics of axon transmembrane polarization in a single closed-form description

    SciTech Connect

    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.

  12. Fitting of NWM Ray-traced Slant Factors to Closed-form Tropospheric Mapping Functions

    NASA Astrophysics Data System (ADS)

    Urquhart, L.; Nievinski, F. G.; Santos, M. C.

    2009-05-01

    Ray-tracing in numerical weather models (NWM) is a promising solution for describing the elevation angle- and azimuth-dependence of tropospheric delay, especially at very low elevation angles, in an attempt to de- correlate vertical position and zenith tropospheric delay during GPS estimation. On the other hand, mapping functions expressed in closed form remain imperative, demanded by the need for (i) fast processing and (ii) convenient distribution to end-users, who employ a variety of third-party GPS processing packages. We investigate the fitting of ray-tracing results to closed-form expressions. We neglect the variation of the tropospheric delay with latitude, longitude, and height, offering a mapping function valid for a specific station site (similarly as done for VMF1-Site [Boehm et al., 1996]). We focus on the variation of the delay with time, elevation angle, and azimuth. For the time-dependence, we choose to work with slant factors instead of slant delays, because the former are more stable in time than the latter; that is a consequence of the normalization by zenith delays which removes the bulk of the variation with time. For the elevation angle-dependence we compare the continued form fraction of Yan and Ping [1995] with that of Marini [1972] (normalized to yield unity at zenith, as given by Herring [1992]). The latter is more commonly used, but the former is expected to provide a better fit at elevation angles below five degrees. Since the ray-tracing results do not necessarily assume azimuthal symmetry, we have to account for the azimuth-dependence. For that we compare the single-direction model of Davis et al. [1993] with the inclusion of secondary directions [Seko et al., 2004] and arbitrary spherical harmonics [Böhm and Schuh, 2001]). We also assess whether physically-oblivious models (i.e., not derived from analytical idealized atmospheric models), such spline or polynomials, as suggested by Rocken et al. [2001], are adequate.

  13. Modeling Production Plant Forming Processes

    SciTech Connect

    Rhee, M; Becker, R; Couch, R; Li, M

    2004-09-22

    Engineering has simulation tools and experience in modeling forming processes. Y-12 personnel have expressed interest in validating our tools and experience against their manufacturing process activities such as rolling, casting, and forging etc. We have demonstrated numerical capabilities in a collaborative DOE/OIT project with ALCOA that is nearing successful completion. The goal was to use ALE3D to model Alcoa's slab rolling process in order to demonstrate a computational tool that would allow Alcoa to define a rolling schedule that would minimize the probability of ingot fracture, thus reducing waste and energy consumption. It is intended to lead to long-term collaboration with Y-12 and perhaps involvement with other components of the weapons production complex. Using simulations to aid in design of forming processes can: decrease time to production; reduce forming trials and associated expenses; and guide development of products with greater uniformity and less scrap.

  14. Spacecraft formation-keeping using a closed-form orbit propagator and optimization technique

    NASA Astrophysics Data System (ADS)

    No, T. S.; Lee, J. G.; Cochran, J. E., Jr.

    2009-08-01

    In this paper, a simple method for modeling the relative orbital motion of multiple spacecraft and their formation-keeping control strategy is presented. Power series and trigonometric functions are used to express the relative orbital motion between the member spacecraft. Their coefficients are obtained using least square regression such that the difference between the exact numerically integrated position vector and the approximate vector obtained from the closed-form propagator is minimized. Then, this closed-form orbit propagator and optimization technique is used to plan a series of impulsive maneuvers which maintain the formation configuration within a specified limit. As an example, formation-keeping of four spacecraft is investigated. The motion projected onto the local horizontal plane (along- and cross-track plane) is a circle with the leader satellite located at its center and follower satellites positioned circumferentially. The radial distance between the leader and the followers, and the relative phase angles between the followers are controlled. Results from the nonlinear simulation are presented.

  15. Closed-form Solutions for Optimal Orbital Transfers Around Oblate Planets

    NASA Astrophysics Data System (ADS)

    Galperin, Alexander; Gurfil, Pini

    2015-07-01

    Optimal spacecraft orbit control has been the subject of extensive research, which resulted in solutions for optimal orbit transfers. A common orbital maneuver problem is the fuel-optimal impulsive transfer between coplanar circular orbits. Three such well-known transfers are the Hohmann transfer, which is an optimal bi-impulsive transfer, the bi-elliptic tri-impulsive transfer, and the bi-parabolic transfer. These solutions were developed based on the Keplerian restricted two-body problem. However, the omission of perturbations results in deviated target orbits and leads to maneuvers that are not actually fuel-optimal. In this paper, the well-known Hohmann, bi-elliptic, and bi-parabolic transfers are modified to accommodate the J 2 zonal harmonic, and new closed-form solutions for the optimal maneuvers are presented. An improvement in maneuver precision is obtained by using an analytical model based on closed-form solutions of motion in the equatorial plane under the effect of J 2. The performance improvement is validated using high-fidelity simulations, which include a myriad of orbital perturbations.

  16. An assessment of some closed-form expressions for the Voigt function

    NASA Astrophysics Data System (ADS)

    Schreier, Franz

    2016-06-01

    Using triangular function approximations of the Gaussian, closed-form analytical representations of the Voigt function K(x , y) in terms of elementary functions can be derived. The performance of the approximations is studied by comparison with more exact numerical algorithms for the closely related complex error function, indicating serious problems for small y.

  17. 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...

  18. An exact frequency equation in closed form for Timoshenko beam clampled at both ends

    NASA Astrophysics Data System (ADS)

    Kang, Jae-Hoon

    2014-07-01

    The author has discovered several errors which are not typographical in the frequency equations for a Timoshenko beam clamped at both ends by Huang who presented the frequency equations and normal mode equations for all six common types of simple, finite beams in closed form for the first time. The exact frequency equations in closed form for Timoshenko beams clamped at both ends are derived based on his analysis. And then in order to justify the amended solutions of Huang, two versions of the closed form exact method and the Ritz method are applied. The frequency equations by the previous researcher present frequencies for only the flexural modes, while the closed form exact method and the Ritz method give ones for the thickness-shear modes as well as the bending modes. The purpose of the present study is to reveal the errors, correct them, and give some numerical results.

  19. 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.

  20. 17 CFR 239.14 - Form N-2 for closed end management investment companies registered on Form N-8A.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at www... closed end management investment companies registered under the Investment Company Act of 1940 on form N... companies pursuant to section 8(b) of the Investment Company Act of 1940 (§ 274.11a-1 of this chapter)....

  1. 17 CFR 239.14 - Form N-2 for closed end management investment companies registered on Form N-8A.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at www... closed end management investment companies registered under the Investment Company Act of 1940 on form N... companies pursuant to section 8(b) of the Investment Company Act of 1940 (§ 274.11a-1 of this chapter)....

  2. 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

    ... of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and on GPO... closed end management investment companies registered under the Investment Company Act of 1940 on form N... companies pursuant to section 8(b) of the Investment Company Act of 1940 (§ 274.11a-1 of this chapter)....

  3. 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

    ... of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at www... closed end management investment companies registered under the Investment Company Act of 1940 on form N... companies pursuant to section 8(b) of the Investment Company Act of 1940 (§ 274.11a-1 of this chapter)....

  4. 17 CFR 239.14 - Form N-2 for closed end management investment companies registered on Form N-8A.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at www... closed end management investment companies registered under the Investment Company Act of 1940 on form N... companies pursuant to section 8(b) of the Investment Company Act of 1940 (§ 274.11a-1 of this chapter)....

  5. Closed-form analytical solutions of high-temperature heat pipe startup and frozen startup limitation

    NASA Technical Reports Server (NTRS)

    Cao, Y.; Faghri, A.

    1992-01-01

    Previous numerical and experimental studies indicate that the high-temperature heat pipe startup process is characterized by a moving hot zone with relatively sharp fronts. Based on the above observation, a flat-front model for an approximate analytical solution is proposed. A closed-form solution related to the temperature distribution in the hot zone and the hot zone length as a function of time are obtained. The analytical results agree well with the corresponding experimental data, and provide a quick prediction method for the heat pipe startup performance. Finally, a heat pipe limitation related to the frozen startup process is identified, and an explicit criterion for the high-temperature heat pipe startup is derived. The frozen startup limit identified in this paper provides a fundamental guidance for high-temperature heat pipe design.

  6. Bayesian Multiscale Modeling of Closed Curves in Point Clouds

    PubMed Central

    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

  7. Closing the energy cycle in an ocean model

    NASA Astrophysics Data System (ADS)

    Eden, Carsten

    2016-05-01

    An effort is discussed to construct a realistic ocean model in Boussinesq approximation which features a closed energy cycle up to numerical precision errors. In such a model, the energy related to the mean variables interacts with all parameterised forms of energy without any spurious energy sources or sinks. First, the concept of the energetics of the model in terms of resolved and unresolved energy variables is outlined using potential and dynamical enthalpy instead of internal and potential energy and without use of the concept of available potential energy. The role of energy transfer terms due to the non-linear, compressible equation of state is clarified. Second, a discretisation of the primitive equations is described in which energy transfers of viscous dissipation and mixing parameterisations are exactly calculated. Third, the model performance is documented using idealised and realistic global model configurations.

  8. ORBITAL DISTRIBUTIONS OF CLOSE-IN PLANETS AND DISTANT PLANETS FORMED BY SCATTERING AND DYNAMICAL TIDES

    SciTech Connect

    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.

  9. Application of damage models in metal forming

    SciTech Connect

    Zhu, Y.Y.; Zacharia, T.

    1995-06-01

    The development of damage models in the analysis of metal forming processes, to characterize the formability limits, is an important area of ongoing research. In this paper, two energy-based damage models for the simulation of crack initiation in metal forming processes are presented. The first one is an isotropic damage model with two damage variables. The second one is an anisotropic model with a damage characteristic tensor. The damage models are developed within the general framework of continuum thermodynamics for irreversible processes by identifying a proper set of internal variables together with their associated generalized forces. An approach is proposed to account for microcrack opening and closing. A viscoplastic regularization algorithm is used to take into account the strain rate effect and to improve numerical stability. Both models have been incorporated into the finite element code, LAGAMINE. The models were applied to simulations of upsetting of collar cylinders and nonisothermal hemispherical punch stretching. The results of the analyses were validated by comparing the finite element simulations with experimentally obtained data.

  10. Scattering by abrupt discontinuities on photonic nanowires: closed-form expressions for domain reduction.

    PubMed

    Li, Guangyuan; Xiong, Qihua

    2014-10-20

    Semiconductor and metallic nanowires are attractive building blocks for a nanoscale integrated photonic platform. The scattering coefficients of the optical or plasmonic waveguide mode by 3-dimensional nanowire abrupt discontinuities including splices and endfaces are important figures of merit for realistic estimation of the coupling, lasing, or sensing performance. To tackle with such computationally challenging problems, we derive simple closed-form expressions based on linear equations and overlap integrals of normal modes to realize domain reduction and efficient analytical modeling. For the reflection coefficients at nanowire/waveguide endfaces, the analytical expressions incorporating all the bound modes and a few dozen leaky modes are highly accurate; whereas for the transmission coefficients at nanowire/waveguide splices, the model can be further simplified because only the input and the interested output bound modes need to be considered. Exhaustive validations using fully-vectorial simulation results as reference data show that the model is accurate and versatile for fundamental and high-order TE or TM modes, and for various architectures including high-index-contrast dielectric and plasmonic configurations, 3-D geometries or 2-D equivalents, and various operating wavelengths from ultraviolet to visible and the optical telecommunication bands in the infrared. Our model will facilitate the structure design and theoretical investigation of nanowire/waveguide photonic devices, especially lasers, resonators, sensors and couplers. PMID:25401546

  11. 12 CFR Appendix A to Part 1013 - Model Forms

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 8 2014-01-01 2014-01-01 false Model Forms A Appendix A to Part 1013 Banks and... A to Part 1013—Model Forms A-1—Model Open-End or Finance Vehicle Lease Disclosures A-2—Model Closed-End or Net Vehicle Lease Disclosures A-3—Model Furniture Lease Disclosures ER19DE11.010...

  12. 12 CFR Appendix A to Part 1013 - Model Forms

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 8 2013-01-01 2013-01-01 false Model Forms A Appendix A to Part 1013 Banks and... A to Part 1013—Model Forms A-1—Model Open-End or Finance Vehicle Lease Disclosures A-2—Model Closed-End or Net Vehicle Lease Disclosures A-3—Model Furniture Lease Disclosures ER19DE11.010...

  13. 12 CFR Appendix A to Part 1013 - Model Forms

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 8 2012-01-01 2012-01-01 false Model Forms A Appendix A to Part 1013 Banks and... A to Part 1013—Model Forms A-1—Model Open-End or Finance Vehicle Lease Disclosures A-2—Model Closed-End or Net Vehicle Lease Disclosures A-3—Model Furniture Lease Disclosures ER19DE11.010...

  14. 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: 10.1007/s10509-011-0691-0 , 2011) discussed all important solutions of charged fluid spheres with pressure and Gupta et al. (Astrophys. Space Sci. doi: 10.1007/s10509-010-0561-1 , 2010) found first closed form solutions of charged Vaidya-Tikekar (V-T) type super-dense star. We extend here the approach evolved by Bijalwan (Astrophys. Space Sci. doi: 10.1007/s10509-011-0691-0 , 2011) to find all possible closed form solutions of V-T type super-dense stars. The existing solutions of Vaidya-Tikekar type charged fluid spheres considering particular form of electric field intensity are being used to model massive stars. Infact at present maximum masses of the star models are found to be 8.223931 M Θ and 8.460857 M Θ subject to ultra-relativistic and non-relativistic conditions respectively. But these stars with such are large masses are not well behaved due to decreasing velocity of sound in the interior of star. We present new results concerning the existence of static, electrically charged perfect fluid spheres that have a regular interior. It is observed that electric intensity used in this article can be used to model superdense stars with ultrahigh surface density of the order 2×1014 gm/cm3 which may have maximum mass 7.26368240 M Θ for ultra-relativistic condition and velocity of sound found to be decreasing towards pressure free interface. We solve the Einstein-Maxwell equations considering a general barotropic equation of state with pressure. For brevity we don't present a detailed analysis of the derived solutions in this paper.

  15. Closed-form solutions for a class of optimal quadratic regulator problems with terminal constraints

    NASA Technical Reports Server (NTRS)

    Juang, J.-N.; Turner, J. D.; Chun, H. M.

    1984-01-01

    Closed-form solutions are derived for coupled Riccati-like matrix differential equations describing the solution of a class of optimal finite time quadratic regulator problems with terminal constraints. Analytical solutions are obtained for the feedback gains and the closed-loop response trajectory. A computational procedure is presented which introduces new variables for efficient computation of the terminal control law. Two examples are given to illustrate the validity and usefulness of the theory.

  16. Modeling of Closed-Die Forging for Estimating Forging Load

    NASA Astrophysics Data System (ADS)

    Sheth, Debashish; Das, Santanu; Chatterjee, Avik; Bhattacharya, Anirban

    2016-05-01

    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.

  17. Closed-form solution for a cantilevered sectorial plate subjected to a tip concentrated force.

    PubMed

    Christy, Carl W; Weggel, David C; Smelser, R E

    2016-01-01

    A closed-form solution is presented for a cantilevered sectorial plate subjected to a tip concentrated force. Since the particular solution for this problem was not found in the literature, it is derived here. Deflections from the total solution (particular plus homogeneous solutions) are compared to those from a finite element analysis and are found to be in excellent agreement, producing an error within approximately 0.08 %. Normalized closed-form deflections and slopes at the fixed support, resulting from an approximate enforcement of the boundary conditions there, deviate from zero by <0.08 %. Finally, the total closed-form solutions for a cantilevered sectorial plate subjected to independent applications of a tip concentrated force, a tip bending moment, and a tip twisting moment, are compiled. PMID:27390653

  18. An efficient closed-form solution for acoustic emission source location in three-dimensional structures

    SciTech Connect

    Li, Xibing; Dong, Longjun

    2014-02-15

    This paper presents an efficient closed-form solution (ECS) for acoustic emission(AE) source location in three-dimensional structures using time difference of arrival (TDOA) measurements from N receivers, N ≥ 6. The nonlinear location equations of TDOA are simplified to linear equations. The unique analytical solution of AE sources for unknown velocity system is obtained by solving the linear equations. The proposed ECS method successfully solved the problems of location errors resulting from measured deviations of velocity as well as the existence and multiplicity of solutions induced by calculations of square roots in existed close-form methods.

  19. Structural comparison between the open and closed forms of citrate synthase from Thermus thermophilus HB8

    PubMed Central

    Kanamori, Eiji; Kawaguchi, Shin-ichi; Kuramitsu, Seiki; Kouyama, Tsutomu; Murakami, Midori

    2015-01-01

    The crystal structures of citrate synthase from the thermophilic eubacteria Thermus thermophilus HB8 (TtCS) were determined for an open form at 1.5 Å resolution and for closed form at 2.3 Å resolution, respectively. In the absence of ligands TtCS in the open form was crystalized into a tetragonal form with a single subunit in the asymmetric unit. TtCS was also co-crystallized with citrate and coenzyme-A to form an orthorhombic crystal with two homodimers in the asymmetric unit. Citrate and CoA are found in the active site situated between the large domain and the small domain in all subunit whereas the complex shows two distinct closed conformations, the fully closed form and partially closed form. Structural comparisons are performed to describe conformational changes associated with binding of products of TtCS. Upon binding of citrate, basic residues in the active site move toward citrate and make a hydrogen bond network in the active site, inducing a large-scale rotation of the small domain relative to the large domain. CoA is sandwiched between the small and large domains and then the cysteamine tail is inserted into the active site with a cooperative rotation around mainchain dihedrals in the hinge region connecting helices M and N. According to this rotation these helices are extended to close the active site completely. The considerable flexibility and structural rearrangements in the hinge region are crucial for an ordered bibi reaction in catalysis for microbial CSs. PMID:27493854

  20. 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...

  1. A closed-form solution to a viscoelastically supported Timoshenko beam under harmonic line load

    NASA Astrophysics Data System (ADS)

    Luo, W. L.; Xia, Y.; Zhou, X. Q.

    2016-05-01

    This study aims to formulate a closed-form solution to a viscoelastically supported Timoshenko beam under a harmonic line load. The differential governing equations of motion are converted into algebraic equations by assuming the deflection and rotation of the beam in harmonic forms with respect to time and space. The characteristic equation is biquadratic and thus contains 14 explicit roots. These roots are then substituted into Cauchy's residue theorem; consequently, five forms of the closed-form solution are generated. The present solution is consistent with that of an Euler-Bernoulli beam on a Winkler foundation, which is a special case of the present problem. The current solution is also verified through numerical examples.

  2. Closed-form recursive formula for an optimal tracker with terminal constraints

    NASA Technical Reports Server (NTRS)

    Juang, J.-N.; Turner, J. D.; Chun, H. M.

    1984-01-01

    Feedback control laws are derived for a class of optimal finite time tracking problems with terminal constraints. Analytical solutions are obtained for the feedback gain and the closed-loop response trajectory. Such formulations are expressed in recursive forms so that a real-time computer implementation becomes feasible. Two examples are given to illustrate the validity and usefulness of the formulations.

  3. A closed-form expression for the Sharma-Mittal entropy of exponential families

    NASA Astrophysics Data System (ADS)

    Nielsen, Frank; Nock, Richard

    2012-01-01

    The Sharma-Mittal entropies generalize the celebrated Shannon, Rényi and Tsallis entropies. We report a closed-form formula for the Sharma-Mittal entropies and relative entropies for arbitrary exponential family distributions. We explicitly instantiate the formula for the case of the multivariate Gaussian distributions and discuss its estimation.

  4. Closed form solution to the optimality equations of minimal norm actuation

    NASA Astrophysics Data System (ADS)

    Guerra, Jorge A.; Ram, Y. M.

    2016-06-01

    The paper deals with natural frequency assignment of vibrating systems by single-input feedback control. A closed form solution to the problem of selecting the input vector which leads to minimal norm of the control gain vector is given. The solution may be applied in applications to reduce the control effort.

  5. Closed-form solutions for estimating a rigid motion from plane correspondences extracted from point clouds

    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

  6. Linear Closed-form Solution and Finite-element Analysis of an Active Tensegrity Unit

    NASA Astrophysics Data System (ADS)

    Kmeť, Stanislav; Platko, Peter

    2012-11-01

    Results of the linear closed form solution of an active or adaptive tensegrity unit, as well as its numerical analysis using finite element method are presented in the paper. The shape of the unit is an octahedral cell with a square base and it is formed by thirteen members (four bottom and four top cables, four edge struts and one central strut). The central strut is designed as an actuator that allows for an adjustment of the shape of the unit which leads to changes of tensile forces in the cables. Due to the diagonal symmetry of the 3D tensegrity unit the closed-form analysis is based on the 2D solution of the equivalent planar biconvex cable system with one central strut under a vertical point load.

  7. Cyclopropenium Cations Break the Rules of Attraction to Form Closely Bound Dimers.

    PubMed

    Wallace, Andrew J; Jayasinghe, Chaminda D; Polson, Matthew I J; Curnow, Owen J; Crittenden, Deborah L

    2015-12-16

    The crystal structures of tris(ethylmethylamino)-cyclopropenium chloride and tris(diethylamino)-cyclopropenium iodide reveal the presence of closely bound dicationic dimers formed from two closed-shell monomer units. The distances between the C3 centroids of the staggered monomers are at the short end of those normally found in π-stacked neutral arenes, let alone charged aromatic rings. Computational analysis reveals that short-range interactions are dominated by strong dispersion forces, enabling metastable dicationic dimers to form without covalent intermolecular bonding. Surrounding counterions then provide a background source of charge balance, imparting strong thermodynamic stability to the system. Additionally, these counterions form a weak but attractive electrostatic bridge between the monomer units, contributing to the surprisingly short observed intermolecular C3-C3 centroid distance. PMID:26584632

  8. Mixture regression models for closed population capture-recapture data.

    PubMed

    Tounkara, Fodé; Rivest, Louis-Paul

    2015-09-01

    In capture-recapture studies, the use of individual covariates has been recommended to get stable population estimates. However, some residual heterogeneity might still exist and ignoring such heterogeneity could lead to underestimating the population size (N). In this work, we explore two new models with capture probabilities depending on both covariates and unobserved random effects, to estimate the size of a population. Inference techniques including Horvitz-Thompson estimate and confidence intervals for the population size, are derived. The selection of a particular model is carried out using the Akaike information criterion (AIC). First, we extend the random effect model of Darroch et al. (1993, Journal of American Statistical Association 88, 1137-1148) to handle unit level covariates and discuss its limitations. The second approach is a generalization of the traditional zero-truncated binomial model that includes a random effect to account for an unobserved heterogeneity. This approach provides useful tools for inference about N, since key quantities such as moments, likelihood functions and estimates of N and their standard errors have closed form expressions. Several models for the unobserved heterogeneity are available and the marginal capture probability is expressed using the Logit and the complementary Log-Log link functions. The sensitivity of the inference to the specification of a model is also investigated through simulations. A numerical example is presented. We compare the performance of the proposed estimator with that obtained under model Mh of Huggins (1989 Biometrika 76, 130-140). PMID:25963047

  9. Benchmarking a new closed-form thermal analysis technique against a traditional lumped parameter, finite-difference method

    SciTech Connect

    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

  10. 34 CFR 300.509 - Model forms.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 2 2011-07-01 2010-07-01 true Model forms. 300.509 Section 300.509 Education... DISABILITIES Procedural Safeguards Due Process Procedures for Parents and Children § 300.509 Model forms. (a) Each SEA must develop model forms to assist parents and public agencies in filing a due...

  11. 34 CFR 300.509 - Model forms.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 34 Education 2 2012-07-01 2012-07-01 false Model forms. 300.509 Section 300.509 Education... DISABILITIES Procedural Safeguards Due Process Procedures for Parents and Children § 300.509 Model forms. (a) Each SEA must develop model forms to assist parents and public agencies in filing a due...

  12. 34 CFR 300.509 - Model forms.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 34 Education 2 2014-07-01 2013-07-01 true Model forms. 300.509 Section 300.509 Education... DISABILITIES Procedural Safeguards Due Process Procedures for Parents and Children § 300.509 Model forms. (a) Each SEA must develop model forms to assist parents and public agencies in filing a due...

  13. 34 CFR 300.509 - Model forms.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 34 Education 2 2013-07-01 2013-07-01 false Model forms. 300.509 Section 300.509 Education... DISABILITIES Procedural Safeguards Due Process Procedures for Parents and Children § 300.509 Model forms. (a) Each SEA must develop model forms to assist parents and public agencies in filing a due...

  14. Closed-form solutions and scaling laws for Kerr frequency combs

    NASA Astrophysics Data System (ADS)

    Renninger, William H.; Rakich, Peter T.

    2016-04-01

    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.

  15. Three-dimensional closed-form costate solutions in optimal coast

    NASA Astrophysics Data System (ADS)

    Pan, Binfeng; Lu, Ping; Chen, Zheng

    2012-08-01

    The costate along a coast arc on an optimal space trajectory contains critically important information about the trajectory. For free-time fuel-optimal flight, the costate at the start of the coast determines completely the optimal length of the coast. Yet most closed-form solutions for costate under various coordinate systems available in the literature are only for two-dimensional flight. In this paper complete three-dimensional closed-form costate solutions in flight-path coordinate system are derived for all conic orbits. These results, as an example of their practical usefulness, enable the optimal duration of any non-circular Keplerian coast arc to be accurately determined from the appropriate root of a polynomial of 5th degree in true anomaly, and a 4th degree polynomial for circular orbits. The value of the development in the paper is demonstrated by solving two relatively difficult multi-finite-burn orbital transfer problems.

  16. Closed-form solutions and scaling laws for Kerr frequency combs

    PubMed Central

    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

  17. Closed-form solutions and scaling laws for Kerr frequency combs.

    PubMed

    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

  18. Closed-form recursive formula for an optimal tracker with terminal constraints

    NASA Technical Reports Server (NTRS)

    Juang, J. N.; Turner, J. D.; Chun, H. M.

    1986-01-01

    Feedback control laws are derived for a class of optimal finite time tracking problems with terminal constraints. Analytical solutions are obtained for the feedback gain and the closed-loop response trajectory. Such formulations are expressed in recursive forms so that a real-time computer implementation becomes feasible. An example involving the feedback slewing of a flexible spacecraft is given to illustrate the validity and usefulness of the formulations.

  19. 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.

  20. Numerical and Experimental Studies on Crash Characteristics of Closed Form Thin—Walled Steel Sections

    NASA Astrophysics Data System (ADS)

    Veerasamy, M.; Srinivasan, K.; Prakash, Raghu V.

    2010-10-01

    The crash behavior of Cold Rolled Mild Steel (CRMS) closed form thin section was studied by conducting compressive tests at loading velocities of 5 mm/min and 1000 mm/min. The numerical simulations were conducted for the same experimental conditions to understand the deformation shape, peak forces and energy absorption capacity of sections at different impact velocities. The simulation results correlated well with the experimental results.

  1. 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.

  2. A closed-form solution for steady-state coupled phloem/xylem flow using the Lambert-W function.

    PubMed

    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. PMID:23617886

  3. 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.

  4. 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

    ... MA-313-B. 308.535 Section 308.535 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION....535 Certificate to be attached to final closing report, Form MA-313-B. The Standard Form of Certificate, Form MA-313-B, shall be attached to the final closing report after cancellation of the...

  5. 46 CFR 308.535 - Certificate to be attached to final closing report, Form MA-313-B.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... MA-313-B. 308.535 Section 308.535 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... § 308.535 Certificate to be attached to final closing report, Form MA-313-B. The Standard Form of Certificate, Form MA-313-B, shall be attached to the final closing report after cancellation of the...

  6. 46 CFR 308.535 - Certificate to be attached to final closing report, Form MA-313-B.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... MA-313-B. 308.535 Section 308.535 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... § 308.535 Certificate to be attached to final closing report, Form MA-313-B. The Standard Form of Certificate, Form MA-313-B, shall be attached to the final closing report after cancellation of the...

  7. 46 CFR 308.535 - Certificate to be attached to final closing report, Form MA-313-B.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... MA-313-B. 308.535 Section 308.535 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... § 308.535 Certificate to be attached to final closing report, Form MA-313-B. The Standard Form of Certificate, Form MA-313-B, shall be attached to the final closing report after cancellation of the...

  8. 46 CFR 308.535 - Certificate to be attached to final closing report, Form MA-313-B.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... MA-313-B. 308.535 Section 308.535 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... § 308.535 Certificate to be attached to final closing report, Form MA-313-B. The Standard Form of Certificate, Form MA-313-B, shall be attached to the final closing report after cancellation of the...

  9. Closed form and geometric algorithms for real-time control of an avatar

    SciTech Connect

    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.

  10. Closed Field Coronal Heating Models Inspired by Wave Turbulence

    NASA Astrophysics Data System (ADS)

    Downs, C.; Lionello, R.; Mikic, Z.; Linker, J.; Velli, M. M.

    2013-12-01

    To simulate the energy balance of coronal plasmas on macroscopic scales, we often require the specification of the coronal heating mechanism in some functional form. To go beyond empirical formulations and to build a more physically motivated heating function, we investigate the wave-turbulence dissipation (WTD) phenomenology for the heating of closed coronal loops. To do so, we employ an implementation of non-WKB equations designed to capture the large-scale propagation, reflection, and dissipation of wave turbulence along a loop. The parameter space of this model is explored by solving the coupled WTD and hydrodynamic equations in 1D for an idealized loop, and the relevance to a range of solar conditions is established by computing solutions for several hundred loops extracted from a realistic 3D coronal field. Due to the implicit dependence of the WTD heating model on loop geometry and plasma properties along the loop and at the footpoints, we find that this model can significantly reduce the number of free parameters when compared to traditional empirical heating models, and still robustly describe a broad range of quiet-sun and active region conditions. The importance of the self-reflection term in producing realistic heating scale heights and thermal non-equilibrium cycles is discussed, and preliminary 3D thermodynamic MHD simulations using this formulation are presented. Research supported by NASA and NSF.

  11. Closed-form near-field expressions for electromagnetic scattering by an electrically small circular aperture on a conducting screen

    NASA Astrophysics Data System (ADS)

    Christou, M. A.; Polycarpou, A. C.

    2015-10-01

    Closed-form expressions were derived for the near-zone scattered fields caused by an obliquely incident plane wave of arbitrary polarization on a sub-wavelength circular aperture on an infinite conducting screen with an infinitesimal thickness. The analysis is based on a quasi-static model of the governing fields in the aperture which was published in the mid 40's by Bethe and improved by Bouwkamp a few years later by incorporating additional terms. Starting with first-order analytical expressions for the magnetic surface current density in the aperture, the scattering problem was formulated using the vector potential F →, the equivalence principle, and the image theory resulting in surface integrals over the aperture which involve the free-space Green's function. Using valid approximations for the near-zone field formulation, closed-form analytical expressions were derived for the corresponding scattered fields along the axis of the aperture. Obtained results based on these closed-form expressions were compared with published data obtained using the spectral-domain method indicating a very good agreement.

  12. Differential commuting operator and closed-form eigenfunctions for linear canonical transforms.

    PubMed

    Pei, Soo-Chang; Liu, Chun-Lin

    2013-10-01

    The linear canonical transform (LCT) with a, b, c, d parameter plays an important role in quantum mechanics, optics, and signal processing. The eigenfunctions of the LCT are also important because they describe the self-imaging phenomenon in optical systems. However, the existing solutions for the eigenfunctions of the LCT are divided into many cases and they lack a systematic way to solve these eigenfunctions. In this paper, we find a linear, second-order, self-adjoint differential commuting operator that commutes with the LCT operator. Hence, the commuting operator and the LCT share the same eigenfunctions with different eigenvalues. The commuting operator is very general and simple when it is compared to the existing multiple-parameter differential equations. Then, the eigenfunctions can be derived systematically. The eigenvalues of the commuting operator have closed-form relationships with the eigenvalues of the LCT. We also simplify the eigenfunctions for |a+d|>2 and a+d=±2, b≠0 into the more compact closed form instead of the integral form. For |a+d|>2, the eigenfunctions are related to the parabolic cylinder functions. PMID:24322865

  13. Closed traumatic brain injury model in sheep mimicking high-velocity, closed head trauma in humans.

    PubMed

    Grimmelt, A-C; Eitzen, S; Balakhadze, I; Fischer, B; Wölfer, J; Schiffbauer, H; Gorji, A; Greiner, C

    2011-08-01

    To date, there are only a few, non-evidence based, cerebroprotective therapeutic strategies for treatment and, accordingly, for prevention of secondary brain injuries following severe closed head trauma. In order to develop new therapy strategies, existing realistic animal models need to be advanced. The objective is to bridge standardized small animal models and actual patient medical care, since the results of experimental small animal studies often cannot be transferred to brain-injured humans. For improved standardization of high-velocity trauma, new trauma devices for initiating closed traumatic brain injury in sheep were developed. The following new devices were tested: 1. An anatomically shaped rubber bolt with an integrated oscillation absorber for prevention of skull fractures; 2. Stationary mounting of the bolt to guarantee stable experimental conditions; 3. Varying degrees of trauma severity, i. e., mild and severe closed traumatic brain injury, using different cartridges; and 4. Trauma analysis via high-speed video recording. Peritraumatic measurements of intracranial pressure, brain tissue pH, brain tissue oxygen, and carbon dioxide pressure, as well as neurotransmitter concentrations were performed. Cerebral injuries were documented with magnetic resonance imaging and compared to neuropathological results. Due to the new trauma devices, skull fractures were prevented. The high-speed video recording documented a realistic trauma mechanism for a car accident. Enhancement of extracellular glutamate, aspartate, and gamma amino butyric acid concentrations began 60 min after the trauma. Magnetic resonance imaging and neuropathological results showed characteristic injury patterns of mild, and severe, closed traumatic brain injury. The severe, closed traumatic brain injury group showed diffuse axonal injuries, traumatic subarachnoid hemorrhage, and hemorrhagic contusions with inconsistent distribution among the animals. The model presented here achieves

  14. 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.

  15. Modeling and simulation of metal forming equipment

    NASA Astrophysics Data System (ADS)

    Frazier, W. G.; Medina, E. A.; Malas, J. C.; Irwin, R. D.

    1997-04-01

    The demand for components made from hard-to-form materials is growing, as is the need to better understand and improve the control of metal forming equipment. Techniques are presented for developing accurate models and computer simulations of metal forming equipment for the purpose of improving metal forming process design. Emphasis is placed on modeling the dynamic behavior of hydraulic vertical forge presses, although similar principles apply to other types of metal forming equipment. These principles are applied to modeling and simulation of a 1000 ton forge press in service at Wright-Patterson Air Force Base, Ohio, along with experimental verification.

  16. Cosmic ray antiprotons in the closed galaxy model

    NASA Technical Reports Server (NTRS)

    Protheroe, R. J.

    1981-01-01

    A calculation is made of the flux of secondary antiprotons expected for the leaky box model and for the closed galaxy model of Peters and Westergaard (1977). The antiproton/proton ratio observed at several GeV is a factor of 4 higher than the prediction for the leaky box model but is consistent with that predicted for the closed galaxy model. It is found that new low-energy data are not consistent with either model. Attention is given to the possibility of a primary antiproton component.

  17. Closed-Form Equation of Data Dependent Jitter in First Order Low Pass System

    PubMed Central

    2014-01-01

    This paper presents a closed-form equation of data dependent jitter (DDJ) in first order low pass systems. The DDJ relates to the system bandwidth, the bit rate, the input rise/fall time, and the number of maximum consecutive identical bits of the data pattern. To confirm the derived equation, simulations have been done with a first order RC low pass circuit for various system bandwidths, bit rates, input rise/fall times, and data patterns. The simulation results agree well with the calculated DDJ values by the derived equation. PMID:25386614

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. A leaky aquifer below Champlain Sea clay: closed-form solutions for natural seepage.

    PubMed

    Chapuis, Robert P; Saucier, Antoine

    2013-01-01

    Closed-form solutions are proposed for natural seepage in semiconfined (leaky) aquifers such as those existing below the massive Champlain Sea clay layers in the Saint-Lawrence River Valley. The solutions are for an ideal horizontal leaky aquifer below an ideal aquitard that may have either a constant thickness and a constant hydraulic head at its surface, or a variable thickness and a variable hydraulic head at its surface. A few simplifying assumptions were needed to obtain the closed-form solutions. These have been verified using a finite element method, which did not make any of the assumptions but gave an excellent agreement for hydraulic heads and groundwater velocities. For example, the difference between the two solutions was smaller than 1 mm for variations in the 5 to 8 m range for the hydraulic head in the semiconfined aquifer. Note that fitting the hydraulic head data of monitoring wells to the theoretical solutions gives only the ratio of the aquifer and aquitard hydraulic conductivities, a clear case of multiple solutions for an inverse problem. Consequently, field permeability tests in the aquitard and the aquifer, and pumping tests in the aquifer, are still needed to determine the hydraulic conductivity values. PMID:23441962

  3. Closed-form solutions for linear regulator design of mechanical systems including optimal weighting matrix selection

    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.

  4. 17 CFR 274.11a-1 - Form N-2, registration statement of closed end management investment companies.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... chapter. Editorial Note: For Federal Register citations affecting Form N-2, see the List of CFR Sections... COMPANY ACT OF 1940 Registration Statements § 274.11a-1 Form N-2, registration statement of closed end... to section 8(b) of the Investment Company Act of 1940 by closed end management investment...

  5. 17 CFR 274.11a-1 - Form N-2, registration statement of closed end management investment companies.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... chapter. Editorial Note: For Federal Register citations affecting Form N-2, see the List of CFR Sections... COMPANY ACT OF 1940 Registration Statements § 274.11a-1 Form N-2, registration statement of closed end... to section 8(b) of the Investment Company Act of 1940 by closed end management investment...

  6. 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

    ... chapter. Editorial Note: For Federal Register citations affecting Form N-2, see the List of CFR Sections... COMPANY ACT OF 1940 Registration Statements § 274.11a-1 Form N-2, registration statement of closed end... to section 8(b) of the Investment Company Act of 1940 by closed end management investment...

  7. 17 CFR 274.11a-1 - Form N-2, registration statement of closed end management investment companies.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... chapter. Editorial Note: For Federal Register citations affecting Form N-2, see the List of CFR Sections... COMPANY ACT OF 1940 Registration Statements § 274.11a-1 Form N-2, registration statement of closed end... to section 8(b) of the Investment Company Act of 1940 by closed end management investment...

  8. 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

    ... chapter. Editorial Note: For Federal Register citations affecting Form N-2, see the List of CFR Sections... COMPANY ACT OF 1940 Registration Statements § 274.11a-1 Form N-2, registration statement of closed end... to section 8(b) of the Investment Company Act of 1940 by closed end management investment...

  9. A Science-Based Approach to Understanding Waste Form Durability in Open and Closed Nuclear Fuel Cycles

    SciTech Connect

    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.

  10. A science-based approach to understanding waste form durability in open and closed nuclear fuel cycles

    NASA Astrophysics Data System (ADS)

    Peters, M. T.; Ewing, R. C.

    2007-05-01

    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 U6+-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 behaviour of the source term over long time periods (greater than 105 years). Such a fundamental and integrated experimental and modelling 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.

  11. The soil water characteristic as new class of closed-form parametric expressions for the flow duration curve

    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.

  12. 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.

  13. Special-case closed form of the Baker-Campbell-Hausdorff formula

    NASA Astrophysics Data System (ADS)

    Van-Brunt, Alexander; Visser, Matt

    2015-06-01

    The Baker-Campbell-Hausdorff formula is a general result for the quantity Z(X,Y)=ln ({{e}X}{{e}Y}), where X and Y are not necessarily commuting. For completely general commutation relations between X and Y, (the free Lie algebra), the general result is somewhat unwieldy. However in specific physics applications the commutator [X,Y], while non-zero, might often be relatively simple, which sometimes leads to explicit closed form results. We consider the special case [X,Y]=uX+vY+cI, and show that in this case the general result reduces to Furthermore we explicitly evaluate the symmetric function f(u,v)=f(v,u), demonstrating that and relate this to previously known results. For instance this result includes, but is considerably more general than, results obtained from either the Heisenberg commutator [P,Q]=-i\\hbar I or the creation-destruction commutator [a,{{a}\\dagger }]=I.

  14. Closed form analysis of a gamma, back-to-back free displacer Stirling engine

    SciTech Connect

    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.

  15. 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.

  16. 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.

  17. 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.

  18. Complete Zonal Problem of the Artificial Satellite: Generic Compact Analytic First Order in Closed Form

    NASA Astrophysics Data System (ADS)

    de Saedeleer, Bernard

    2005-03-01

    This paper is a contribution to the Theory of the Artificial Satellite, within the frame of the Lie Transform as canonical perturbation technique (elimination of the short period terms). We consider the perturbation by any zonal harmonic J n (n ≥ 2) of the primary on the satellite, what we call here the complete zonal problem of the artificial satellite. This is quite useful for primaries with symmetry of revolution. We give an analytical formula to compute directly the first order averaged Hamiltonian. The computation is carried out in closed form for all terms, avoiding therefore tedious expansions in the eccentricity or in any anomaly; this feature makes the averaging process, not only valid for all kind of elliptic trajectories but at the same time it yields the averaged Hamiltonian in a very short and compact way. The formula allows us to now skip the averaging process, which means an asymptotic gain of a factor 3n/2 regarding the computational cost of the n th zonal. Our analytical formulae have been widely checked, by comparison on one hand with published works (Brouwer, 1959) (which contained results for particular zonal harmonics, let’s say typically from J 2 to J 8), and on the other hand with the results of 3 symbolic manipulation software, among which the MM (standing for ‘Moon’s series Manipulator’), which has already been used and described in (De Saedeleer B., 2004). Additionally, the first order generator associated with this transformation is given into the same closed form, and has also been validated.

  19. Structure of steady state accretion shocks with several cooling functions: Closed integral-form solution

    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.

  20. Effective closed form mathematical approach to determine kinetic constants of NR vulcanized with sulphur and accelerators at different concentrations

    SciTech Connect

    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.

  1. A closed-form solution of wake-fields in an elliptical pill-box by using an elliptical coordinate system

    NASA Astrophysics Data System (ADS)

    Yang, J. S.; Chen, K. W.

    1989-10-01

    It was known from a complete model analysis1,2 that the wake potential in the pill-box cavity is predominantly determined by a few longitudinal modes counting from the fundamental longitudinal mode. An approach to find the longitudinal modes of an elliptical cavity is developed by means of the coordinate transformation method. It is found that the field configuration and eigenfrequencies of the elliptical cavity can be expressed in a closed form in terms of Mathieu functions. Inserting the closed form solution of modes into the previous analytical formula for the wake field, the wake field is expressed too in a closed form solution, which is convenient for numerical calculation. Thus, a numerical method to calculate expediently the wake field is developed, and a model calculation is presented.

  2. Similarity Measure Learning in Closed-Form Solution for Image Classification

    PubMed Central

    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. PMID:25057510

  3. Closed-form expressions for ocean reverberation and signal excess with mode stripping and Lambert's law

    NASA Astrophysics Data System (ADS)

    Harrison, C. H.

    2003-11-01

    Closed-form expressions for two-way propagation and reverberation in variable depth ducts are derived for isovelocity water by using ray invariants and acoustic flux. These expressions include the transition to single mode propagation at long range. Three surface scattering laws are considered: Lambert, Lommel-Seeliger, and angle independent, and these are compared with a point target to give explicit signal-to-reverberation ratios. In particular, there is interesting and sometimes surprising behavior when the propagation obeys mode-stripping (the high angles are preferentially attenuated by bottom losses) whilst the scattering obeys Lambert's law (high angles are preferentially back-scattered). There may be conditions where the signal-to-reverberation ratio is independent of range so that there is no reverberation range limit. Bottom slope dependence of both target echo and reverberation is surprisingly weak. The implications of refraction are discussed. The angle dependence for a point or surface scatterer at a given range can be translated into arrival time, so it is possible to calculate the received pulse shape for one-way or two-way paths. Because the tail is exponential with a range-independent half-life that only depends on bottom reflection properties there is scope for extracting geoacoustic information from the pulse shape alone. This environmental time spread is also of use to sonar designers.

  4. Closed-form analysis of fiber-matrix interface stresses under thermo-mechanical loadings

    NASA Technical Reports Server (NTRS)

    Naik, Rajiv A.; Crews, John H., Jr.

    1992-01-01

    Closed form techniques for calculating fiber matrix (FM) interface stresses, using repeating square and diamond regular arrays, were presented for a unidirectional composite under thermo-mechanical loadings. An Airy's stress function micromechanics approach from the literature, developed for calculating overall composite moduli, was extended in the present study to compute FM interface stresses for a unidirectional graphite/epoxy (AS4/3501-6) composite under thermal, longitudinal, transverse, transverse shear, and longitudinal shear loadings. Comparison with finite element results indicate excellent agreement of the FM interface stresses for the square array. Under thermal and longitudinal loading, the square array has the same FM peak stresses as the diamond array. The square array predicted higher stress concentrations under transverse normal and longitudinal shear loadings than the diamond array. Under transverse shear loading, the square array had a higher stress concentration while the diamond array had a higher radial stress concentration. Stress concentration factors under transverse shear and longitudinal shear loadings were very sensitive to fiber volume fraction. The present analysis provides a simple way to calculate accurate FM interface stresses for both the square and diamond array configurations.

  5. 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.

  6. Dielectric elastomer composites: A general closed-form solution in the small-deformation limit

    NASA Astrophysics Data System (ADS)

    Spinelli, Stephen A.; Lefèvre, Victor; Lopez-Pamies, Oscar

    2015-10-01

    A solution for the overall electromechanical response of two-phase dielectric elastomer composites with (random or periodic) particulate microstructures is derived in the classical limit of small deformations and moderate electric fields. In this limit, the overall electromechanical response is characterized by three effective tensors: a fourth-order tensor describing the elasticity of the material, a second-order tensor describing its permittivity, and a fourth-order tensor describing its electrostrictive response. Closed-form formulas are derived for these effective tensors directly in terms of the corresponding tensors describing the electromechanical response of the underlying matrix and the particles, and the one- and two-point correlation functions describing the microstructure. This is accomplished by specializing a new iterative homogenization theory in finite electroelastostatics (Lopez-Pamies, 2014) to the case of elastic dielectrics with even coupling between the mechanical and electric fields and, subsequently, carrying out the pertinent asymptotic analysis. Additionally, with the aim of gaining physical insight into the proposed solution and shedding light on recently reported experiments, specific results are examined and compared with an available analytical solution and with new full-field simulations for the special case of dielectric elastomers filled with isotropic distributions of spherical particles with various elastic dielectric properties, including stiff high-permittivity particles, liquid-like high-permittivity particles, and vacuous pores.

  7. Modeling Gas Exchange in a Closed Plant Growth Chamber

    NASA Technical Reports Server (NTRS)

    Cornett, J. D.; Hendrix, J. E.; Wheeler, R. M.; Ross, C. W.; Sadeh, W. Z.

    1994-01-01

    Fluid transport models for fluxes of water vapor and CO2 have been developed for one crop of wheat and three crops of soybean grown in a closed plant a growth chamber. Correspondence among these fluxes is discussed. Maximum fluxes of gases are provided for engineering design requirements of fluid recycling equipment in growth chambers. Furthermore, to investigate the feasibility of generalized crop models, dimensionless representations of water vapor fluxes are presented. The feasibility of such generalized models and the need for additional data are discussed.

  8. Modeling gas exchange in a closed plant growth chamber

    NASA Technical Reports Server (NTRS)

    Cornett, J. D.; Hendrix, J. E.; Wheeler, R. M.; Ross, C. W.; Sadeh, W. Z.

    1994-01-01

    Fluid transport models for fluxes of water vapor and CO2 have been developed for one crop of wheat and three crops of soybean grown in a closed plant growth chamber. Correspondence among these fluxes is discussed. Maximum fluxes of gases are provided for engineering design requirements of fluid recycling equipment in growth chambers. Furthermore, to investigate the feasibility of generalized crop models, dimensionless representations of water vapor fluxes are presented. The feasibility of such generalized models and the need for additional data are discussed.

  9. Close Human Interaction Recognition Using Patch-Aware Models.

    PubMed

    Yu Kong; Yun Fu

    2016-01-01

    This paper addresses the problem of recognizing human interactions with close physical contact from videos. Due to ambiguities in feature-to-person assignments and frequent occlusions in close interactions, it is difficult to accurately extract the interacting people. This degrades the recognition performance. We, therefore, propose a hierarchical model, which recognizes close interactions and infers supporting regions for each interacting individual simultaneously. Our model associates a set of hidden variables with spatiotemporal patches and discriminatively infers their states, which indicate the person that the patches belong to. This patch-aware representation explicitly models and accounts for discriminative supporting regions for individuals, and thus overcomes the problem of ambiguities in feature assignments. Moreover, we incorporate the prior for the patches to deal with frequent occlusions during interactions. Using the discriminative supporting regions, our model builds cleaner features for individual action recognition and interaction recognition. Extensive experiments are performed on the BIT-Interaction data set and the UT-Interaction data set set #1 and set #2, and validate the effectiveness of our approach. PMID:26561435

  10. 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.

  11. Mechanical Behavior of Salt Caverns: Closed-Form Solutions vs Numerical Computations

    NASA Astrophysics Data System (ADS)

    Wang, Linlin; Bérest, Pierre; Brouard, Benoît

    2015-11-01

    Creep closure and structural stability of a cylindrical elongated cavern leached out from a salt formation are discussed. The Norton-Hoff creep law, or "power law", is used to capture the main features of salt rheological behavior. Two failure criteria are considered: (1) shear stresses must not be larger than a certain fraction of the mean stress (dilation criterion); and (2) the effective stress at the cavern wall (actual stress plus cavern fluid pressure) must not be tensile. The case of a brine-filled cavern whose pressure is kept constant is discussed first. It is proved that creep closure reaches a steady state such that stresses in the rock mass remain constant. However, decades are needed to reach such a state. During the transient phase that results from the slow redistribution of stresses in the rock mass, deviatoric stresses decrease at the vicinity of the cavern wall, and onset of dilation is less and less likely. At this point, the case of a rapid brine pressure increase, typical of a tightness test, is considered. It is proved that during such a swift pressure increase, cavern behavior is almost perfectly elastic; there is no risk of dilation onset. However, even when cavern pressure remains significantly smaller than geostatic, the effective stress at cavern wall can become tensile. These results, obtained through numerical computations, are confirmed by closed-form solutions obtained in the case of an idealized perfectly cylindrical cavern; these solutions provide a better insight into the main structural features of the behavior of the cavern.

  12. 34 CFR 300.509 - Model forms.

    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...

  13. Enabling comparative modeling of closely related genomes: Example genus Brucella

    DOE PAGESBeta

    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; et al

    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

  14. Comparison of closed loop model with flight test results

    NASA Technical Reports Server (NTRS)

    George, F. L.

    1981-01-01

    An analytic technique capable of predicting the landing characteristics of proposed aircraft configurations in the early stages of design was developed. In this analysis, a linear pilot-aircraft closed loop model was evaluated using experimental data generated with the NT-33 variable stability in-flight simulator. The pilot dynamics are modeled as inner and outer servo loop closures around aircraft pitch attitude, and altitude rate-of-change respectively. The landing flare maneuver is of particular interest as recent experience with military and other highly augmented vehicles shows this task to be relatively demanding, and potentially a critical design point. A unique feature of the pilot model is the incorporation of an internal model of the pilot's desired flight path for the flare maneuver.

  15. Turbulence Modeling in Dust Forming Media

    NASA Astrophysics Data System (ADS)

    Helling, Ch.; Lüttke, M.; Sedlmayr, E.; Oeverman, M.; Klein, R.

    The process of dust formation is considered in a turbulent medium. The modeling for hydro- and thermodynamics follows the classical approach for an inviscid, compressible fluid and the dust formation process is described as a two step process, nucleation and growth, including element conservation. Our approach is to combine asymptotic techniques and multi-dimensional direct numerical simulations (DNS). The turbulence modeling will be performed by the simulation of regime-wise increased scales allowing for a detailed study of the corresponding behavior of the dust forming gas flow. Our investigations have been started in the microscopic scale regime (Kolmogoroff scale << lref << density scale height) where acoustic waves are continuously generated by turbulent motions caused by large-scale convection. We show that the local gas temperature can fall below a temperature threshold for efficient dust nucleation by the superposition of acoustic expansion waves. As the formed seed particles subsequently grow, radiation cooling is intensified causing new dust to form and a runaway effect sets in. An asymptotic model serves as an independent test of our DNS results and allows an investigation of the long term behavior of our dust forming system. Adopting the example of a brown dwarf atmosphere, intermittent dust distributions in space and time (clouds) are predicted by asymptotic calculations of stochastic acoustic interaction and have been studied further by 1D and 2D DNS.

  16. A parallel offline CFD and closed-form approximation strategy for computationally efficient analysis of complex fluid flows

    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

  17. Simulation model for the closed plant experiment facility of CEEF.

    PubMed

    Abe, Koichi; Ishikawa, Yoshio; Kibe, Seishiro; Nitta, Keiji

    2005-01-01

    The Closed Ecology Experiment Facilities (CEEF) is a testbed for Controlled Ecological Life Support Systems (CELSS) investigations. CEEF including the physico-chemical material regenerative system has been constructed for the experiments of material circulation among plants, breeding animals and crew of CEEF. Because CEEF is a complex system, an appropriate schedule for the operation must be prepared in advance. The CEEF behavioral Prediction System, CPS, that will help to confirm the operation schedule, is under development. CPS will simulate CEEFs behavior with data (conditions of equipments, quantity of materials in tanks, etc.) of CEEF and an operation schedule that will be made by the operation team everyday, before the schedule will be carried out. The result of the simulation will show whether the operation schedule is appropriate or not. In order to realize CPS, models of the simulation program that is installed in CPS must mirror the real facilities of CEEF. For the first step of development, a flexible algorithm of the simulation program was investigated. The next step was development of a replicate simulation model of the material circulation system for the Closed Plant Experiment Facility (CPEF) that is a part of CEEF. All the parts of a real material circulation system for CPEF are connected together and work as a complex mechanism. In the simulation model, the system was separated into 38 units according to its operational segmentation. In order to develop each model for its corresponding unit, specifications for the model were fixed based on the specifications of the real part. These models were put into a simulation model for the system. PMID:16175692

  18. Simulation model for the closed plant experiment facility of CEEF

    NASA Astrophysics Data System (ADS)

    Abe, Koichi; Ishikawa, Yoshio; Kibe, Seishiro; Nitta, Keiji

    The Closed Ecology Experiment Facilities (CEEF) is a testbed for Controlled Ecological Life Support Systems (CELSS) investigations. CEEF including the physico-chemical material regenerative system has been constructed for the experiments of material circulation among plants, breeding animals and crew of CEEF. Because CEEF is a complex system, an appropriate schedule for the operation must be prepared in advance. The CEEF behavioral Prediction System, CPS, that will help to confirm the operation schedule, is under development. CPS will simulate CEEFs behavior with data (conditions of equipments, quantity of materials in tanks, etc.) of CEEF and an operation schedule that will be made by the operation team everyday, before the schedule will be carried out. The result of the simulation will show whether the operation schedule is appropriate or not. In order to realize CPS, models of the simulation program that is installed in CPS must mirror the real facilities of CEEF. For the first step of development, a flexible algorithm of the simulation program was investigated. The next step was development of a replicate simulation model of the material circulation system for the Closed Plant Experiment Facility (CPEF) that is a part of CEEF. All the parts of a real material circulation system for CPEF are connected together and work as a complex mechanism. In the simulation model, the system was separated into 38 units according to its operational segmentation. In order to develop each model for its corresponding unit, specifications for the model were fixed based on the specifications of the real part. These models were put into a simulation model for the system.

  19. Simulation model for the Closed Plant Experimental Facilities of CEEF

    NASA Astrophysics Data System (ADS)

    Abe, K.; Ishikawa, Y.; Kibe, S.; Nitta, K.

    The Closed Ecology Experiment Facilities (CEEF) is a testbed for CELSS investigations. CEEF including the physico-chemical material regenerative system has been constructed for the experiments of material circulation among plants, breeding animals, humans (crew of the CEEF). Because CEEF is a complex system, an appropriate schedule for the operation must be prepared in advance. The CEEF behavioral Prediction System, CPS, that will help to confirm the operation schedule, is under development. CPS will simulate CEEF's behavior with data (conditions of equipments, quantity of materials in tanks, etc.) of CEEF and an operation schedule that will be made by the operation team everyday, before the schedule will be carried out. The result of the simulation will show whether the operation schedule is appropriate or not. In order to realize CPS, models of the simulation program that is installed in CPS must mirror the real facilities of CEEF. A flexible algorithm for the first step of development of the simulation program was already investigated. The next step was development of a replicate simulation model of the material circulation system for the Closed Plant Experimental Facilities (CPEF) that is a part of CEEF. All the parts of real material circulation system for CPEF are connected together and work as a complex mechanism. In the simulation model, the system was separated into 38 units according to its operational segmentation. In order to develop each model for its corresponding unit, specifications for the model were fixed based on the specifications of the real part. These models were put into a simulation model for the system.

  20. Exact closed-form solution for the electrostatic interaction of two equal-sized charged conducting spheres

    NASA Astrophysics Data System (ADS)

    Banerjee, Shubho; Levy, Mason

    2015-10-01

    We provide an exact closed-form solution for the electrostatic interaction of two equal-sized conducting spheres. We calculate the capacitance coefficients for the spheres in terms of the q-analogue of the digamma function. In the near limit, when the two spheres are about to touch, the closed-form exact solutions allow for much faster numerical calculations than the well-known infinite series solutions. By analyzing the exact solution in the near limit, we provide Taylor series expressions for the capacitance coefficients in terms of the surface-to- surface separation of the two spheres.

  1. Clinical Forms and Animal Models of Hypophosphatasia.

    PubMed

    Salles, Jean Pierre

    2015-01-01

    Hypophosphatasia (HPP) is due to mutations of the tissue non-specific alkaline phosphatase (TNAP) gene expressed in the liver, kidney, and bone. TNAP substrates include inorganic pyrophosphate cleaved into inorganic phosphate (Pi) in bone, pyridoxal-5'-phosphate (PLP), the circulating form of vitamin B6, and phosphoethanolamine (PEA). As an autosomal recessive or dominant disease, HPP results in a range of clinical forms. Its hallmarks are low alkaline phosphatase (AP) and elevated PLP and PEA levels. Perinatal HPP may cause early death with respiratory insufficiency and hypomineralization resulting in deformed limbs and sometimes near-absence of bones and skull. Infantile HPP is diagnosed before 6 months of life. Respiratory failure, rib fractures and seizures due to vitamin B6 deficiency in the brain indicate poor prognosis. Craniosynostosis is frequent. Unlike in other forms of rickets, calcium and phosphorus are not decreased, resulting in hypercalciuria and nephrocalcinosis. Hypercalcemic crisis may occur. Failure to thrive and growth retardation are concerns. In infantile and adult forms of HPP, non-traumatic fractures may be the prominent manifestation, with otherwise unexplained chronic pain. Progressive myopathy has been described. Dental manifestations with early loss of teeth are usual in HPP and in a specific form, odontohypophosphatasia. HPP has been studied in knock-out mice models which mimic its severe form. Animal models have made a major contribution to the development of an original enzyme therapy for human infantile HPP, which is however essentially targeted at mineralized tissues. Better knowledge of its extraskeletal manifestations, including pain and neurological symptoms, is therefore required. PMID:26219704

  2. Accuracy issues in modeling superplastic metal forming

    SciTech Connect

    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.

  3. Mechanical models of close approaches and collisions of large protoplanets

    NASA Technical Reports Server (NTRS)

    Kaula, W. M.; Beachey, A. E.

    1984-01-01

    In models of lunar origin by great impact, attention is usually paid to the hydrodynamic expansion resulting from the great amount of thermal energy. However, the source of this disruption is inevitably significant in a close approach between large bodies, it is to be expected that significant departures from simple hyperbolic orbits would occur even before impact. These departures could arise from mechanical effects, and hence purely mechanical models are worth pursuing. The most interesting results obtained for approach offsets are small multiples of the planet radius and approach velocities of a few kilometers/second. In an interaction between Mars and Earth sized protoplanets, most of the material ends in collision, but a few percent end in elliptic orbits and a few percent escape. Another model considered is an offset collision, arising from a wide range of approach velocities and offsets.

  4. Seeing Perfectly Fitting Factor Models That Are Causally Misspecified: Understanding That Close-Fitting Models Can Be Worse

    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…

  5. Regge calculus models of the closed vacuum Λ -FLRW universe

    NASA Astrophysics Data System (ADS)

    Liu, Rex G.; Williams, Ruth M.

    2016-01-01

    The Collins-Williams Regge calculus models of Friedmann-Lemaître-Robertson-Walker (FLRW) space-times and Brewin's subdivided models are applied to closed vacuum Λ -FLRW universes. In each case, we embed the Regge Cauchy surfaces into 3-spheres in E4 and consider possible measures of Cauchy surface radius that can be derived from the embedding. Regge equations are obtained from both global variation, where entire sets of identical edges get varied simultaneously, and local variation, where each edge gets varied individually. We explore the relationship between the two sets of solutions, the conditions under which the Regge Hamiltonian constraint would be a first integral of the evolution equation, the initial value equation for each model at its moment of time symmetry, and the performance of the various models. It is revealed that local variation does not generally lead to a viable Regge model. It is also demonstrated that the various models do satisfy their respective initial value equations. Finally, it is shown that the models reproduce the correct qualitative dynamics of the space-time. Furthermore, the approximation's accuracy is highest when the universe is small but improves overall as we increase the number of tetrahedra used to construct the Regge Cauchy surface. Eventually though, all models gradually fail to keep up with the continuum FLRW model's expansion, with the models with lower numbers of tetrahedra falling away more quickly. We believe this failure to keep up is due to the finite resolution of the Regge Cauchy surfaces trying to approximate an ever expanding continuum Cauchy surface; each Regge surface has a fixed number of tetrahedra and as the surface being approximated gets larger, the resolution would degrade. Finally, we note that all Regge models end abruptly at a point when the timelike struts of the skeleton become null, though this end point appears to get delayed as the number of tetrahedra is increased.

  6. 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... Model privacy form and examples. (a) Model privacy form. Use of the model privacy form in appendix A of... content requirements of §§ 160.6 and 160.7 of this part, although use of the model privacy form is...

  7. 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

  8. 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.

  9. Modeling the glass forming ability of metals

    NASA Astrophysics Data System (ADS)

    Cheney, Justin Lee

    A design protocol for the discovery of novel metallic glass compositions has been developed using a multi-model approach. By using a series of modeling criteria, all aspects of vitrification in metals can be simultaneously analyzed, and optimum compositions for metallic glass formation can be accurately determined. The modeling tools used focus on three aspects common among good glass forming alloy: compositional proximity to a deep eutectic, development of strong chemical interactions in the liquid state, and an ordered local topology in the amorphous state. It was shown that metallic glasses have the tendency to form two separate local topologies, that based on solvent-solute clustering, and that based on solute-solute clustering. A chemical short range order parameter model was used to evaluate constituent element interactions, and distinguish between these two structure types. In solvent-solute clusters, metallic glass design involves maximizing the packing density in the cluster structure; in the solute-solute cluster case, metallic glass design requires maximizing the elastic strain as a function of the solute composition. A quantification method, termed the alpha parameter, was developed to determine the depth of a eutectic, and rank alloy compositions among a large multi-dimensional composition space. This modeling approach was shown to accurately predict the wide range of metallic glass types represented in the literature. Furthermore, novel metallic glass compositions were developed according to this model. These novel compositions are among the most cost-effective bulk metallic glasses, which belong to three distinct alloy systems, Fe-Cr-Mo-C-B-W, Fe-Nb-Cr-B, and Ti-Ni-Cu-Si-Sn.

  10. Chemical Models of Star-Forming Cores

    NASA Astrophysics Data System (ADS)

    Aikawa, Y.

    2013-10-01

    We review chemical models of low-mass star forming cores including our own work. Chemistry in molecular clouds are not in equilibrium. Molecular abundances in star forming cores change not only with physical conditions in cores but also with time. In prestellar cores, temperature stays almost constant ˜ 10 K, while the gas density increases as the core collapses. Three chemical phenomena are observed in this cold phase: molecular depletion, chemical fractionation, and deuterium enrichment. They are reproduced by chemical models combined with isothermal gravitational collapse. The collapse timescale of prestellar cores depends on the initial ratios of thermal, turbulent and magnetic pressure to gravitational energy. Since the chemical timescales, such as adsorption timescale of gas particle onto grains, are comparable to the collapse timescale, molecular abundances in cores should vary depending on the collapse timescale. Observations found that molecular abundances in some cores deviate from those in other cores, in spite of their similar central densities; it could originate in the pressure to gravity ratio in the cores. As the core contraction proceeds, compressional heating eventually overwhelms radiative cooling, and the core starts to warm up. Temperature of the infalling gas rises, as it approaches the central region. Grain-surface reactions of adsorbed molecules occur in this warm-up phase, as well as in prestellar phase. Hydrogenation is efficient at T ≤ 20 K, whereas radicals can migrate on grain surface and react with each other to form complex organic molecules (COMs) at T ≥ 30 K. Grain-surface species are sublimated to the gas phase and re-start gas-phase reactions; e.g. unsaturated carbon chains are formed from sublimated methane. Our model calculation predicts that COMs increases as the warm region extends outwards and the abundances of unsaturated carbon chains depend on the gas density in the CH4 sublimation zone. Recent detection of COMs in

  11. A chloride capturing system via proton-induced structure transformation between opened- and closed-forms of dodecavanadates.

    PubMed

    Inoue, Yoshitaka; Kikukawa, Yuji; Kuwajima, Sho; Hayashi, Yoshihito

    2016-05-01

    Chloride-incorporated dodecavanadates show two distinct structures of the monoprotonated-form [HV12O32(Cl)](4-) (closed-V12) with a spherical closed-structure and the opened-form [V12O32(Cl)](5-) (opened-V12). The reaction of closed-V12 with a stoichiometric amount of ethylenediamine drives the structure transformation reaction to opened-V12, quantitatively. From time dependent observations of (51)V NMR, a tube-type intermediate [V12O32(Cl)](5-) (tube-V12) was observed in the transformation process. Isolation of the intermediate was achieved by the deprotonation reaction of closed-V12 with diethylamine, and the structure transformation was confirmed by using the isolated intermediate. The reverse transformation from opened-V12 to closed-V12 was also achieved by addition of trifluoroacetic acid. The geometrical difference between closed-V12 and opened-V12 is reflected in the reactivity difference to the external reagents, and this was demonstrated by examining the chloride removal reaction by using a silver cation. The incorporated chloride was preserved in the closed-V12 cage even in the presence of a silver cation. In contrast, the chloride in opened-V12 was removed as AgCl by the silver cation. In addition, by the reaction of chloride-free opened-V12 with a quantitative amount of {Et4N}Cl retrieved opened-V12, showing the capability of opened-V12 to recapture a guest chloride in the cavity. This transformation between two isomeric dodecavanadate structures is regarded as the movement of a molecular mitt to catch a ball and secure it. PMID:27112216

  12. An equilibrium model for linear and closed-loop amyloid fibril formation

    PubMed Central

    Yang, Shuo; Griffin, Michael D. W.; Binger, Katrina J.; Schuck, Peter; Howlett, Geoffrey J.

    2014-01-01

    Amyloid fibrils and their soluble oligomeric intermediates are implicated in several age-related diseases including Alzheimer’s and Parkinson’s disease. The distribution of oligomers and fibrils is related to toxicity and is dependent on the pathways for fibril assembly, generally considered to occur via a slow nucleation step that precedes fibril elongation. Human apolipoprotein (apo) C-II forms amyloid fibrils via a reversible self-assembly process accompanied by closed-loop formation and fibril breaking and joining. Our fluorescence quenching and sedimentation velocity experiments with Alexa488-labelled apoC-II indicated a time-dependent sub-unit interchange for both linear and closed-loop fibrils, while dilution experiments using mature fibrils indicated a shift to smaller size distributions consistent with a reversible assembly pathway. To account for this behaviour we developed an equilibrium self-association model that describes the final size distributions of apoC-II fibrils formed at different starting concentrations. The model proposes a reversible isomerisation of apoC-II monomer to form an active conformer that self-assembles into fibrils via an isodesmic self-association pathway coupled to fibril length-dependent closed-loop formation. The model adequately described fibril size distributions and the proportion of closed-loops as a function of total apoC-II concentration over the concentration range 0.1–0.5 mg/ml. Extension of the model to include the rates of isomerisation, self-association and fibril breaking and joining provided satisfactory global fits to kinetic data on fibril formation and changes in average fibril size at different apoC-II starting concentrations. The model provides a simple thermodynamic description of the processes governing the size distribution of apoC-II fibrils at equilibrium and the formation of discrete oligomeric intermediates. PMID:22370559

  13. An equilibrium model for linear and closed-loop amyloid fibril formation.

    PubMed

    Yang, Shuo; Griffin, Michael D W; Binger, Katrina J; Schuck, Peter; Howlett, Geoffrey J

    2012-08-10

    Amyloid fibrils and their soluble oligomeric intermediates are implicated in several age-related diseases including Alzheimer's and Parkinson's diseases. The distribution of oligomers and fibrils is related to toxicity and is dependent on the pathways for fibril assembly, generally considered to occur via a slow nucleation step that precedes fibril elongation. Human apolipoprotein (apo) C-II forms amyloid fibrils via a reversible self-assembly process accompanied by closed-loop formation and fibril breaking and joining. Our fluorescence quenching and sedimentation velocity experiments with Alexa488-labeled apoC-II indicated a time-dependent subunit interchange for both linear and closed-loop fibrils, while dilution experiments using mature fibrils indicated a shift to smaller size distributions consistent with a reversible assembly pathway. To account for this behavior, we developed an equilibrium self-association model that describes the final size distributions of apoC-II fibrils formed at different starting concentrations. The model proposes a reversible isomerization of apoC-II monomer to form an active conformer that self-assembles into fibrils via an isodesmic self-association pathway coupled to fibril length-dependent closed-loop formation. The model adequately described fibril size distributions and the proportion of closed loops as a function of total apoC-II concentration over the concentration range 0.1-0.5 mg/ml. Extension of the model to include the rates of isomerization, self-association and fibril breaking and joining provided satisfactory global fits to kinetic data on fibril formation and changes in average fibril size at different apoC-II starting concentrations. The model provides a simple thermodynamic description of the processes governing the size distribution of apoC-II fibrils at equilibrium and the formation of discrete oligomeric intermediates. PMID:22370559

  14. Rapid cellular translocation is related to close contacts formed between various cultured cells and their substrata.

    PubMed

    Kolega, J; Shure, M S; Chen, W T; Young, N D

    1982-04-01

    Interference-reflection microscopy combined with time-lapse cinemicrography was used to examine the relationship between cell-to-substratum contact patterns and the speeds of translocation for a variety of cell types. Rapid translocation of amphibian leukocytes (average speed = 9.0 micron/min), amphibian epidermal cells (7 micron/min) and teleost epidermal cells (7 micron/min) was found to correlate with patterns of broad grey close contacts. Similar contact patterns were found under freshly seeded (2 h) chick heart fibroblasts (moving 1-3 micron/min), the rapidly advancing (1-5 micron/min) margin of spreading human WI-38 fibroblasts, and isolated MDCK canine epithelial cells (0.5-1.0 micron/min). Conversely, numerous dark streaks of focal contact were found associated with the slow rate of translocation displayed by older cultures (72 h) of chick fibroblasts (less than 0.1 micron/min), well-spread WI-38 cells (less than or equal to 0.3 micron/min) and confluent MDCK cells (less than 0.01 micron/min). It is concluded that close contacts, but not focal contacts, are associated with rapid cellular translocation, and that the build-up of focal contacts is associated with reduced cellular translocation and maintenance of the spread cell shape. PMID:7076724

  15. Molecular dynamics simulations of the bacterial ABC transporter SAV1866 in the closed form.

    PubMed

    St-Pierre, Jean-François; Bunker, Alex; Róg, Tomasz; Karttunen, Mikko; Mousseau, Normand

    2012-03-01

    The ATP binding cassette (ABC) transporter family of proteins contains members involved in ATP-mediated import or export of ligands at the cell membrane. For the case of exporters, the translocation mechanism involves a large-scale conformational change that involves a clothespin-like motion from an inward-facing open state, able to bind ligands and adenosine triphosphate (ATP), to an outward-facing closed state. Our work focuses on SAV1866, a bacterial member of the ABC transporter family for which the structure is known for the closed state. To evaluate the ability of this protein to undergo conformational changes at physiological temperature, we first performed conventional molecular dynamics (MD) on the cocrystallized adenosine diphosphate (ADP)-bound structure and on a nucleotide-free structure. With this assessment of SAV1866's stability, conformational changes were induced by steered molecular dynamics (SMD), in which the nucleotide binding domains (NBD) were pushed apart, simulating the ATP hydrolysis energy expenditure. We found that the transmembrane domain is not easily perturbed by large-scale motions of the NBDs. PMID:22339391

  16. 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... INFORMATION (REGULATION P) § 1016.2 Model privacy form and examples. (a) Model privacy form. Use of the model... model privacy form is not required. (b) Examples. The examples in this part are not...

  17. 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... INFORMATION (REGULATION P) § 1016.2 Model privacy form and examples. (a) Model privacy form. Use of the model... model privacy form is not required. (b) Examples. The examples in this part are not...

  18. 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... INFORMATION (REGULATION P) § 1016.2 Model privacy form and examples. (a) Model privacy form. Use of the model... model privacy form is not required. (b) Examples. The examples in this part are not...

  19. Stochastic Model of Gap Junctions Exhibiting Rectification and Multiple Closed States of Slow Gates.

    PubMed

    Snipas, Mindaugas; Kraujalis, Tadas; Paulauskas, Nerijus; Maciunas, Kestutis; Bukauskas, Feliksas F

    2016-03-29

    Gap-junction (GJ) channels formed from connexin (Cx) proteins provide direct pathways for electrical and metabolic cell-cell communication. Earlier, we developed a stochastic 16-state model (S16SM) of voltage gating of the GJ channel containing two pairs of fast and slow gates, each operating between open (o) and closed (c) states. However, experimental data suggest that gates may in fact contain two or more closed states. We developed a model in which the slow gate operates according to a linear reaction scheme, o↔c1↔c2, where c1 and c2 are initial-closed and deep-closed states that both close the channel fully, whereas the fast gate operates between the open state and the closed state and exhibits a residual conductance. Thus, we developed a stochastic 36-state model (S36SM) of GJ channel gating that is sensitive to transjunctional voltage (Vj). To accelerate simulation and eliminate noise in simulated junctional conductance (gj) records, we transformed an S36SM into a Markov chain 36-state model (MC36SM) of GJ channel gating. This model provides an explanation for well-established experimental data, such as delayed gj recovery after Vj gating, hysteresis of gj-Vj dependence, and the low ratio of functional channels to the total number of GJ channels clustered in junctional plaques, and it has the potential to describe chemically mediated gating, which cannot be reflected using an S16SM. The MC36SM, when combined with global optimization algorithms, can be used for automated estimation of gating parameters including probabilities of c1↔c2 transitions from experimental gj-time and gj-Vj dependencies. PMID:27028642

  20. Maximum precision closed-form solution for localizing diffraction-limited spots in noisy images

    PubMed Central

    Larkin, Joshua D.; Cook, Peter R.

    2012-01-01

    Super-resolution techniques like PALM and STORM require accurate localization of single fluorophores detected using a CCD. Popular localization algorithms inefficiently assume each photon registered by a pixel can only come from an area in the specimen corresponding to that pixel (not from neighboring areas), before iteratively (slowly) fitting a Gaussian to pixel intensity; they fail with noisy images. We present an alternative; a probability distribution extending over many pixels is assigned to each photon, and independent distributions are joined to describe emitter location. We compare algorithms, and recommend which serves best under different conditions. At low signal-to-noise ratios, ours is 2-fold more precise than others, and 2 orders of magnitude faster; at high ratios, it closely approximates the maximum likelihood estimate. PMID:23038398

  1. Experimental and Mathematical Models for Small Aqueous Closed Ecosystems with Spatially Separated Components

    NASA Astrophysics Data System (ADS)

    Pisman, T. I.; Pechurkin, N. S.; Babkin, A. V.; Somova, L. A.; Sarangova, A. B.

    1999-01-01

    Experimental and theoretical models of closed ``autotroph-heteretroph'' (chlorella-yeast, chlorella- protozoa) ecosystems with spatially separated components have been created and studied. The chart of flows and interaction of components of gas-closed ``chlorella-yeast'' system have formed the basis describe mathematically the functioning of the given system, experimental results have been found to agree with computer solution of the problem in terms of quality. Investigation of the experimental model of the ``producer-consumer'' trophic chain demonstrated the role of protozoa in nitrogen turnover. ``Production-decomposition'' and ``production-grazing-decomposition'' cycle models has been theoretically analyzed and compared. The predator has been shown to be a more intensive mineralizer than the reducer component.

  2. Closed-form inverse kinematics for intra-operative mobile C-arm positioning with six degrees of freedom

    NASA Astrophysics Data System (ADS)

    Wang, Lejing; Zou, Rui; Weidert, Simon; Landes, Juergen; Euler, Ekkehard; Burschka, Darius; Navab, Nassir

    2011-03-01

    For trauma and orthopedic surgery, maneuvering a mobile C-arm X-ray device into a desired position in order to acquire the right picture is a routine task. The precision and ease of use of the C-arm positioning becomes even more important for more advanced imaging techniques as parallax-free X-ray image stitching, for example. Standard mobile C-arms have only five degrees of freedom (DOF), which definitely restricts their motions that have six DOF in 3D Cartesian space. We have proposed a method to model the kinematics of the mobile Carm and operating table as an integrated 6DOF C-arm X-ray imaging system.1 This enables mobile C-arms to be positioned relative to the patient's table with six DOF in 3D Cartesian space. Moving mobile C-arms to a desired position and orientation requires finding the necessary joint values, which is an inverse kinematics problem. In this paper, we present closed-form solutions, i.e. analytic expressions, obtained in an algebraic way for the inverse kinematics problem of the 6DOF C-arm model. In addition, we implement a 6DOF C-arm system for interactively radiation-free C-arm positioning based on a continuous guidance from C-arm pose estimation. For this we employ a visual marker pattern attached under the operating table and a mobile C-arm system augmented by a video camera and mirror construction. In our experiment, repositioning C-arm to a pre-defined pose in a phantom study demonstrates the practicality and accuracy of our developed 6DOF C-arm system.

  3. Closed-form solutions for linear regulator-design of mechanical systems including optimal weighting matrix selection

    NASA Technical Reports Server (NTRS)

    Hanks, Brantley R.; Skelton, Robert E.

    1991-01-01

    This paper addresses the restriction of Linear Quadratic Regulator (LQR) solutions to the algebraic Riccati Equation to design spaces which can be implemented as passive structural members and/or dampers. A general closed-form solution to the optimal free-decay control problem is presented which is tailored for structural-mechanical systems. 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. Some examples of simple spring mass systems are shown to illustrate key points.

  4. Hysterically damped free and forced vibrations of axial and torsional bars by a closed form exact method

    NASA Astrophysics Data System (ADS)

    Kang, Jae-Hoon

    2016-09-01

    Hysterically damped free and forced vibrations of axial and torsional bars are investigated using a closed form exact method. The method is exact and yields closed form expressions for the vibratory displacements. This is in contrast with the well known eigenfunction superposition method which requires expressing the distributed forcing functions and the displacement response functions as infinite sums of free vibration eigenfunctions. The hysterically damped free vibration frequencies and corresponding damped mode shapes are calculated and plotted instead of undamped free vibration and mode shapes which is typically computed and applied in vibration problems. The hysterically damped natural frequency equations are exactly derived. Accurate axial or torsional amplitude vs. forcing frequency curves showing the forced response due to distributed loading are displayed with various hysteretic damping parameters.

  5. A Drosophila model of closed head traumatic brain injury

    PubMed Central

    Katzenberger, Rebeccah J.; Loewen, Carin A.; Wassarman, Douglas R.; Petersen, Andrew J.; Ganetzky, Barry; Wassarman, David A.

    2013-01-01

    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. PMID:24127584

  6. Closed-Head TBI Model of Multiple Morbidity.

    PubMed

    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

  7. Closed-form SEM solution to the transient far-field response of a thin-wire antenna

    NASA Astrophysics Data System (ADS)

    Hoorfar, Ahmad

    1994-05-01

    A closed-form SEM representation for the transient far-field response of a thin-wire cylindrical antenna is derived, and explicit expressions for all of the corresponding SEM parameters are presented. In particular, a so-called time-dependent natural far-field mode is introduced, and its corresponding integral is analytically evaluated. Excellent agreements with the numerical results are obtained.

  8. 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...

  9. 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... 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...

  10. 17 CFR Appendix to Subpart B of... - Model Forms

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 17 Commodity and Securities Exchanges 3 2013-04-01 2013-04-01 false Model Forms Appendix to... to Subpart B of Part 248—Model Forms a. Although you and your affiliates are not required to use the model forms in this Appendix, use of a model form (if applicable to each person that uses it)...

  11. 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...

  12. 17 CFR Appendix to Subpart B of... - Model Forms

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 17 Commodity and Securities Exchanges 4 2014-04-01 2014-04-01 false Model Forms Appendix to.... Appendix to Subpart B of Part 248—Model Forms a. Although you and your affiliates are not required to use the model forms in this appendix, use of a model form (if applicable to each person that uses...

  13. 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...

  14. 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...

  15. 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...

  16. 12 CFR Appendix A to Part 573 - Model Privacy Form

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... the model form under this part, must comply with section 624 of the FCRA and 12 CFR part 571, subpart... 12 Banks and Banking 6 2013-01-01 2012-01-01 true Model Privacy Form A Appendix A to Part 573... INFORMATION Pt. 573, App. A Appendix A to Part 573—Model Privacy Form A. The Model Privacy Form...

  17. 12 CFR Appendix A to Part 573 - Model Privacy Form

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... the model form under this part, must comply with section 624 of the FCRA and 12 CFR part 571, subpart... 12 Banks and Banking 5 2011-01-01 2011-01-01 false Model Privacy Form A Appendix A to Part 573... INFORMATION Pt. 573, App. A Appendix A to Part 573—Model Privacy Form A. The Model Privacy Form...

  18. 12 CFR Appendix A to Part 573 - Model Privacy Form

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... the model form under this part, must comply with section 624 of the FCRA and 12 CFR part 571, subpart... 12 Banks and Banking 6 2012-01-01 2012-01-01 false Model Privacy Form A Appendix A to Part 573... INFORMATION Pt. 573, App. A Appendix A to Part 573—Model Privacy Form A. The Model Privacy Form...

  19. 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...

  20. 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...

  1. 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...

  2. 17 CFR Appendix to Subpart B of... - Model Forms

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 17 Commodity and Securities Exchanges 3 2011-04-01 2011-04-01 false Model Forms Appendix to... to Subpart B of Part 248—Model Forms a. Although you and your affiliates are not required to use the model forms in this Appendix, use of a model form (if applicable to each person that uses it)...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 17 CFR Appendix to Subpart B of... - Model Forms

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 17 Commodity and Securities Exchanges 3 2012-04-01 2012-04-01 false Model Forms Appendix to... to Subpart B of Part 248—Model Forms a. Although you and your affiliates are not required to use the model forms in this Appendix, use of a model form (if applicable to each person that uses it)...

  12. 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...

  13. 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...

  14. 12 CFR Appendix A to Part 573 - Model Privacy Form

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... the model form under this part, must comply with section 624 of the FCRA and 12 CFR part 571, subpart... 12 Banks and Banking 6 2014-01-01 2012-01-01 true Model Privacy Form A Appendix A to Part 573... INFORMATION Pt. 573, App. A Appendix A to Part 573—Model Privacy Form A. The Model Privacy Form...

  15. 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...

  16. 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...

  17. 12 CFR Appendix A to Part 573 - Model Privacy Form

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the model form under this part, must comply with section 624 of the FCRA and 12 CFR part 571, subpart... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Model Privacy Form A Appendix A to Part 573... INFORMATION Pt. 573, App. A Appendix A to Part 573—Model Privacy Form A. The Model Privacy Form...

  18. 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...

  19. 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

  20. A new closed form expression for the total reaction cross-section of heavy ions

    SciTech Connect

    Rego, R.A. ); Hussein, M.S. )

    1989-01-01

    A new analytical expression for the H1 total reaction cross-section which exhibits that macroscopic features of the transparency factor is derived. Comparison with optical model calculation are made for the /sup 12/C + /sup 208/Pb and /sup 16/O + /sup 208/Pb at several energies.

  1. 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.

  2. Modeling Aerosol-Cloud Interactions in Marine Open- and Closed-Cell Stratocumulus

    NASA Astrophysics Data System (ADS)

    Wang, H.; Feingold, G.

    2008-12-01

    Satellite imagery shows the recurrence of striking images of cellular structures exhibiting both closed- and open-cell patterns in marine stratocumulus fields. The open-cell region has much lower cloud albedo than closed cells. Aside from that, previous observational and modeling studies have suggested that open- and closed-cell regions are different in many other aspects, such as concentration of cloud condensation nuclei (CCN), cloud droplet number and size, precipitation efficiency, and cloud dynamics. In this work, aerosol- cloud interactions and dynamical feedbacks are investigated within a large eddy simulation (LES) modeling framework to study the activation, cloud scavenging, mixing and transport of CCN in the open- and closed- cell boundary layer and near the open/closed-cell boundaries. The model domain size of 120 km by 60 km is large enough to represent mesoscale organizations that are associated with different cellular structures and that are promoted by CCN perturbation from ship emissions. Simulation results show that depletion of CCN by collision and coalescence in clouds is critical to the formation of precipitation and open-cell structure in a stratocumulus deck. Once the open cellular structure has formed in the clean environment, a substantial increase of CCN transported from a neighboring polluted environment or from ship emissions do not close it during the 12-hour simulation due to the lack of dynamical and moisture support in the open-cell cloud-free region. However, the contaminated open cells are not able to self-sustain as a result of shutoff of precipitation. This points to the critical role of precipitation-triggered circulations in maintaining an open-cellular structure.

  3. 12 CFR Appendix to Part 1016 - Model Privacy Form

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 8 2014-01-01 2014-01-01 false Model Privacy Form Appendix to Part 1016 Banks... (REGULATION P) Pt. 1016, App. Appendix to Part 1016—Model Privacy Form A. The Model Privacy Form ER21DE11.058.... How the Model Privacy Form Is Used (a) The model form may be used, at the option of a...

  4. 12 CFR Appendix A to Part 40 - Model Privacy Form

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 1 2014-01-01 2014-01-01 false Model Privacy Form A Appendix A to Part 40... INFORMATION Pt. 40, App. A Appendix A to Part 40—Model Privacy Form A. The Model Privacy Form ER01DE09.000.... How the Model Privacy Form Is Used (a) The model form may be used, at the option of a...

  5. 12 CFR Appendix to Part 1016 - Model Privacy Form

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 8 2012-01-01 2012-01-01 false Model Privacy Form Appendix to Part 1016 Banks... (REGULATION P) Pt. 1016, App. Appendix to Part 1016—Model Privacy Form A. The Model Privacy Form ER21DE11.058.... How the Model Privacy Form Is Used (a) The model form may be used, at the option of a...

  6. 12 CFR Appendix A to Part 40 - Model Privacy Form

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 1 2011-01-01 2011-01-01 false Model Privacy Form A Appendix A to Part 40... INFORMATION Pt. 40, App. A Appendix A to Part 40—Model Privacy Form A. The Model Privacy Form ER01DE09.000.... How the Model Privacy Form Is Used (a) The model form may be used, at the option of a...

  7. 12 CFR Appendix A to Part 40 - Model Privacy Form

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 1 2012-01-01 2012-01-01 false Model Privacy Form A Appendix A to Part 40... INFORMATION Pt. 40, App. A Appendix A to Part 40—Model Privacy Form A. The Model Privacy Form ER01DE09.000.... How the Model Privacy Form Is Used (a) The model form may be used, at the option of a...

  8. 12 CFR Appendix A to Part 40 - Model Privacy Form

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 1 2013-01-01 2013-01-01 false Model Privacy Form A Appendix A to Part 40... INFORMATION Pt. 40, App. A Appendix A to Part 40—Model Privacy Form A. The Model Privacy Form ER01DE09.000.... How the Model Privacy Form Is Used (a) The model form may be used, at the option of a...

  9. 12 CFR Appendix to Part 1016 - Model Privacy Form

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 8 2013-01-01 2013-01-01 false Model Privacy Form Appendix to Part 1016 Banks... (REGULATION P) Pt. 1016, App. Appendix to Part 1016—Model Privacy Form A. The Model Privacy Form ER21DE11.058.... How the Model Privacy Form Is Used (a) The model form may be used, at the option of a...

  10. IMC-PID design based on model matching approach and closed-loop shaping.

    PubMed

    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. PMID:24280534

  11. Optical properties of bud scales and protochlorophyll(ide) forms in leaf primordia of closed and opened buds.

    PubMed

    Solymosi, Katalin; Böddi, Béla

    2006-08-01

    The transmission spectra of bud scales of 14 woody species and the 77 K fluorescence emission spectra of the innermost leaf primordia of closed and opened buds of 37 woody species were studied. Pigment concentrations were determined in some species. Bud scales had low transmittance between 400 and 680 nm with a local minimum around 680 nm. Transmittance increased steeply above 680 nm and was > 80% in the 700-800 nm spectral region. Significant protochlorophyllide (Pchlide) accumulation was observed in leaf primordia of tightly packed, closed buds with relatively thick, dark bud scales. In common ash (Fraxinus excelsior L.) and Hungarian ash (Fraxinus angustifolia Vahl.), the innermost leaf primordia of the closed buds contained protochlorophyll (Pchl) and Pchlide (abbreviated as Pchl(ide)), but no chlorophyll. We observed Pchl(ide) forms with emission maxima at 633, 643 and 655 nm in these leaves. Complete transformation of Pchlide(655) (protochlorophyllide form with maximum emission at 655 nm) into Chlide(692) (chlorophyllide form with maximum emission at 692 nm) occurred after irradiation for 10 s. The innermost leaf primordia of the buds of four species (flowering ash (Fraxinus ornus L.), horse chestnut (Aesculus hippocastanum L.), tree of heaven (Ailanthus altissima P. Mill.) and common walnut (Juglans regia L.)) contained Pchl(ide)(633), Pchl(ide)(643) and Pchlide(655) as well as an emission band at 688 nm corresponding to a chlorophyll form. The Pchlide(655) was fully photoactive in these species. The outermost leaf primordia of these four species and the innermost leaf primordia of 28 other species contained all of the above described Pchl(ide) forms in various ratios but in small amounts. In addition, Chl forms were present and the main bands in the fluorescence emission spectra were at 690 or 740 nm, or both. The results indicate that Pchl(ide) accumulation occurs in leaf primordia in near darkness inside the tightly closed buds, where the bud scales and

  12. Differential transcriptional regulation of orthologous dps genes from two closely related heterocyst-forming cyanobacteria.

    PubMed

    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. PMID:25663155

  13. Fast closed-form calculation of THz field enhancement in a metal nanoslit

    SciTech Connect

    Novitsky, A. V.; Lavrinenko, A. V.

    2010-10-07

    Strong electric field enhancement in a metal nanoslit with THz field illumination is hardly calculated using the standard simulation packages. It is explained by the considerable difference of the values of nano sizes of the slit and the wavelength of the incident radiation (up to 10000 times). Therefore, significant computational resources or/and the home-made simulation code is needed. We offer the simple single-parameter model as an alternative to the time consuming calculations. The single parameter can be calculated either from the experimental or simulation data (one reference point is necessary to determine one parameter). Then we can find the field enhancement for different slit geometries and light wavelengths.

  14. 12 CFR Appendix A to Part 704 - Model Forms

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 6 2011-01-01 2011-01-01 false Model Forms A Appendix A to Part 704 Banks and... Pt. 704, App. A Appendix A to Part 704—Model Forms This appendix contains sample forms intended for... Prioritization and Model Forms Part I—Optional Capital Prioritization Notwithstanding any other provision in...

  15. A novel form of {open_quotes}Tyrosinase-positive{close_quotes} oculocutaneous albinism

    SciTech Connect

    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.

  16. FORMING CLOSE-IN EARTH-LIKE PLANETS VIA A COLLISION-MERGER MECHANISM IN LATE-STAGE PLANET FORMATION

    SciTech Connect

    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.

  17. Cystic Fibrosis Transmembrane Conductance Regulator (CFTR): CLOSED AND OPEN STATE CHANNEL MODELS.

    PubMed

    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. PMID:26229102

  18. Kirchhoff approximation and closed-form expressions for atom-surface scattering

    NASA Astrophysics Data System (ADS)

    Marvin, A. M.

    1980-12-01

    In this paper an approximate solution for atom-surface scattering is presented beyond the physical optics approximation. The potential is well represented by a hard corrugated surface but includes an attractive tail in front. The calculation is carried out analytically by two different methods, and the limit of validity of our formulas is well established in the text. In contrast with other workers, I find those expressions to be exact in both limits of small (Rayleigh region) and large momenta (classical region), with the correct behavior at the threshold. The result is attained through a particular use of the extinction theorem in writing the scattered amplitudes, hitherto not employed, and not for particular boundary values of the field. An explicit evaluation of the field on the surface shows in fact the present formulas to be simply related to the well known Kirchhoff approximation (KA) or more generally to an "extended" KA fit to the potential model above. A possible application of the theory to treat strong resonance-overlapping effects is suggested in the last part of the work.

  19. 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.

  20. CFORM- LINEAR CONTROL SYSTEM DESIGN AND ANALYSIS: CLOSED FORM SOLUTION AND TRANSIENT RESPONSE OF THE LINEAR DIFFERENTIAL EQUATION

    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.

  1. The ectomycorrhizal morphotype Pinirhiza sclerotia is formed by Acephala macrosclerotiorum sp. nov., a close relative of Phialocephala fortinii.

    PubMed

    Münzenberger, Babette; Bubner, Ben; Wöllecke, Jens; Sieber, Thomas N; Bauer, Robert; Fladung, Matthias; Hüttl, Reinhard F

    2009-09-01

    Relatively few ectomycorrhizal fungal species are known to form sclerotia. Usually, sclerotia are initiated at the extraradical mycelium. In this study, we present anatomical and ultrastructural evidence for the formation of sclerotia directly in the hyphal mantle of the mycorrhizal morphotype Pinirhiza sclerotia. A dark-pigmented fungal strain was isolated from Pinirhiza sclerotia and identified by molecular tools as Acephala macrosclerotiorum sp. nov., a close relative of Phialocephala fortinii s.l. As dark septate fungi are known to be mostly endophytic, resyntheses with Pinus sylvestris and A. macrosclerotiorum as well as Populus tremula x Populus tremuloides and A. macrosclerotiorum or P. fortinii s.l. were performed under axenic conditions. No mycorrhizas were found when hybrid aspen was inoculated with A. macrosclerotiorum or P. fortinii. However, A. macrosclerotiorum formed true ectomycorrhizas in vitro with P. sylvestris. Anatomical and ultrastructural features of this ectomycorrhiza are presented. The natural and synthesized ectomycorrhizal morphotypes were identical and characterized by a thin hyphal mantle that bore sclerotia in a later ontogenetic stage. The Hartig net was well-developed and grew up to the endodermis. To our knowledge, this is the first evidence at the anatomical and ultrastructural level that a close relative of P. fortinii s.l. forms true ectomycorrhizas with a coniferous host. PMID:19415343

  2. Closed Form Solutions for Unsteady Free Convection Flow of a Second Grade Fluid over an Oscillating Vertical Plate

    PubMed Central

    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

  3. Relativistic closed-form Hamiltonian for many-body gravitating systems in the post-Minkowskian approximation.

    PubMed

    Ledvinka, Tomás; Schäfer, Gerhard; Bicák, Jirí

    2008-06-27

    The Hamiltonian for a system of relativistic bodies interacting by their gravitational field is found in the post-Minkowskian approximation, including all terms linear in the gravitational constant. It is given in a surprisingly simple closed form as a function of canonical variables describing the bodies only. The field is eliminated by solving inhomogeneous wave equations, applying transverse-traceless projections, and using the Routh functional. By including all special relativistic effects our Hamiltonian extends the results described in classical textbooks of theoretical physics. As an application, the scattering of relativistic objects is considered. PMID:18643648

  4. A Murine Closed-chest Model of Myocardial Ischemia and Reperfusion

    PubMed Central

    Kim, Se-Chan; Boehm, Olaf; Meyer, Rainer; Hoeft, Andreas; Knüfermann, Pascal; Baumgarten, Georg

    2012-01-01

    Surgical trauma by thoracotomy in open-chest models of coronary ligation induces an immune response which modifies different mechanisms involved in ischemia and reperfusion. Immune response includes cytokine expression and release or secretion of endogenous ligands of innate immune receptors. Activation of innate immunity can potentially modulate infarct size. We have modified an existing murine closed-chest model using hanging weights which could be useful for studying myocardial pre- and postconditioning and the role of innate immunity in myocardial ischemia and reperfusion. This model allows animals to recover from surgical trauma before onset of myocardial ischemia. Volatile anesthetics have been intensely studied and their preconditioning effect for the ischemic heart is well known. However, this protective effect precludes its use in open chest models of coronary artery ligation. Thus, another advantage could be the use of the well controllable volatile anesthetics for instrumentation in a chronic closed-chest model, since their preconditioning effect lasts up to 72 hours. Chronic heart diseases with intermittent ischemia and multiple hit models are other possible applications of this model. For the chronic closed-chest model, intubated and ventilated mice undergo a lateral blunt thoracotomy via the 4th intercostal space. Following identification of the left anterior descending a ligature is passed underneath the vessel and both suture ends are threaded through an occluder. Then, both suture ends are passed through the chest wall, knotted to form a loop and left in the subcutaneous tissue. After chest closure and recovery for 5 days, mice are anesthetized again, chest skin is reopened and hanging weights are hooked up to the loop under ECG control. At the end of the ischemia/reperfusion protocol, hearts can be stained with TTC for infarct size assessment or undergo perfusion fixation to allow morphometric studies in addition to histology and

  5. Closed-Form Solution for the Effect of Fuel Decay and Thermoelectric Degradation on Output of SiGe RTGs

    SciTech Connect

    Schock, Alfred

    1991-08-01

    Presented at the 26th IECEC in Boston, MA August 4-9, 1991. The paper derives a closed-form solution for the long-term effect of fuel decay and thermoelectric degradation on the performance of Radioisotope Thermoelectric Generators employing silicon-germanium converter elements. RTGs of this type were used to power the recent Galileo and Ulysses space exploration missions, and are slated for use on the upcoming CRAF and Cassini missions. The method described applies not only to uniform-temperature RTGs, but also to RTGs with significant axial and circumferential variations in the couples' cold-junction temperatures and voltages (due to unsymmetrically obstructed heat rejection paths). This is important for the mutually blocking RTGs on the CRAF and Cassini spacecraft, and even more so for the reflector-blocked Solar Probe RTGs. The method for predicting RTG degradation that is dervied in this paper is based on both analytical and experimental data. It accounts for the effect of diminishing hot-junction temperatures on thermoelectric degradation rates. The method leads to an integral equation, for which the author was able to derive a closed-form solution. The solution was successfully validated by comparison with long-term test data. It enables the RTG designer to predict the power output profile throughout the mission, to ensure that it satisfies the mission's power demand profile. There are four copies in the file.

  6. Closed-form Static Analysis with Inertia Relief and Displacement-Dependent Loads Using a MSC/NASTRAN DMAP Alter

    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.

  7. MSC/NASTRAN DMAP Alter Used for Closed-Form Static Analysis With Inertia Relief and Displacement-Dependent Loads

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Solving for the displacements of free-free coupled systems acted upon by static loads is a common task in the aerospace industry. Often, these problems are solved by static analysis with inertia relief. This technique allows for a free-free static analysis by balancing the applied loads with the 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 the displacement-dependent loads. A launch vehicle being acted upon by an aerodynamic loading can have such applied loads. The final displacements of such systems are commonly determined with iterative solution techniques. Unfortunately, these techniques can be time consuming and labor intensive. Because 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. An MSC/NASTRAN (MacNeal-Schwendler Corporation/NASA Structural Analysis) DMAP (Direct Matrix Abstraction Program) Alter was used to include displacement-dependent loads in static analysis with inertia relief. It efficiently solved a common aerospace problem that typically has been solved with an iterative technique.

  8. Information-theoretic model selection and model averaging for closed-population capture-recapture studies

    USGS Publications Warehouse

    Stanley, T.R.; Burnham, K.P.

    1998-01-01

    Specification of an appropriate model is critical to valid stalistical inference. Given the "true model" for the data is unknown, the goal of model selection is to select a plausible approximating model that balances model bias and sampling variance. Model selection based on information criteria such as AIC or its variant AICc, or criteria like CAIC, has proven useful in a variety of contexts including the analysis of open-population capture-recapture data. These criteria have not been intensively evaluated for closed-population capture-recapture models, which are integer parameter models used to estimate population size (N), and there is concern that they will not perform well. To address this concern, we evaluated AIC, AICc, and CAIC model selection for closed-population capture-recapture models by empirically assessing the quality of inference for the population size parameter N. We found that AIC-, AICc-, and CAIC-selected models had smaller relative mean squared errors than randomly selected models, but that confidence interval coverage on N was poor unless unconditional variance estimates (which incorporate model uncertainty) were used to compute confidence intervals. Overall, AIC and AICc outperformed CAIC, and are preferred to CAIC for selection among the closed-population capture-recapture models we investigated. A model averaging approach to estimation, using AIC. AICc, or CAIC to estimate weights, was also investigated and proved superior to estimation using AIC-, AICc-, or CAIC-selected models. Our results suggested that, for model averaging, AIC or AICc. should be favored over CAIC for estimating weights.

  9. 17 CFR Appendix A to Part 160 - Model Privacy Form

    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 A Appendix... Part 160—Model Privacy Form A. The Model Privacy Form ER28DE12.003 ER28DE12.004 ER28DE12.005 ER28DE12.006 ER28DE12.007 ER28DE12.008 ER28DE12.009 B. General Instructions 1. How the Model Privacy Form...

  10. 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...

  11. 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. 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. This appendix contains five model credit application forms, each designated for use in a...

  13. 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... PROGRAM Disclosures as Conditions for Federal Payment § 50.17 Use of model forms. (a) Policies in force on... requirement if it uses NAIC Model Disclosure Form No. 2. (2) An insurer that is required to make...

  14. 12 CFR Appendix A to Part 716 - Model Privacy Form

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... the model form under this part, must comply with section 624 of the FCRA and 12 CFR part 717, subpart... 12 Banks and Banking 7 2012-01-01 2012-01-01 false Model Privacy Form A Appendix A to Part 716... CONSUMER FINANCIAL INFORMATION Pt. 716, App. A Appendix A to Part 716—Model Privacy Form A.The...

  15. 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 model credit application forms, each designated for use in a particular type of consumer...

  16. 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. This appendix contains five model credit application forms, each designated for use in a...

  17. 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... PROGRAM Disclosures as Conditions for Federal Payment § 50.17 Use of model forms. (a) Policies in force on... requirement if it uses NAIC Model Disclosure Form No. 2. (2) An insurer that is required to make...

  18. 12 CFR Appendix A to Part 716 - Model Privacy Form

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... the model form under this part, must comply with section 624 of the FCRA and 12 CFR part 717, subpart... 12 Banks and Banking 7 2013-01-01 2013-01-01 false Model Privacy Form A Appendix A to Part 716... CONSUMER FINANCIAL INFORMATION Pt. 716, App. A Appendix A to Part 716—Model Privacy Form A.The...

  19. 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 model credit application forms, each designated for use in a particular type of consumer...

  20. 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 model credit application forms, each designated for use in a particular type of consumer...

  1. 12 CFR Appendix A to Part 716 - Model Privacy Form

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the model form under this part, must comply with section 624 of the FCRA and 12 CFR part 717, subpart... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Model Privacy Form A Appendix A to Part 716... CONSUMER FINANCIAL INFORMATION Pt. 716, App. A Appendix A to Part 716—Model Privacy Form A.The...

  2. 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... PROGRAM Disclosures as Conditions for Federal Payment § 50.17 Use of model forms. (a) Policies in force on... requirement if it uses NAIC Model Disclosure Form No. 2. (2) An insurer that is required to make...

  3. 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. This appendix contains five model credit application forms, each designated for use in a...

  4. 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. This appendix contains five model credit application forms, each designated for use in a...

  5. 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... PROGRAM Disclosures as Conditions for Federal Payment § 50.17 Use of model forms. (a) Policies in force on... requirement if it uses NAIC Model Disclosure Form No. 2. (2) An insurer that is required to make...

  6. 12 CFR Appendix A to Part 716 - Model Privacy Form

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... the model form under this part, must comply with section 624 of the FCRA and 12 CFR part 717, subpart... 12 Banks and Banking 6 2011-01-01 2011-01-01 false Model Privacy Form A Appendix A to Part 716... CONSUMER FINANCIAL INFORMATION Pt. 716, App. A Appendix A to Part 716—Model Privacy Form A.The...

  7. Deposit model for closed-basin potash-bearing brines

    USGS Publications Warehouse

    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.

  8. Solid state forms of 4-aminoquinaldine - From void structures with and without solvent inclusion to close packing

    PubMed Central

    Braun, Doris E.; Gelbrich, Thomas; Kahlenberg, Volker; Griesser, Ulrich J.

    2015-01-01

    Polymorphs of 4-aminoquinaldine (4-AQ) have been predicted in silico and experimentally identified and characterised. The two metastable forms, AH (anhydrate) II and AH III, crystallise in the trigonal space group R3¯ and are less densely packed than the thermodynamically most stable phase AH I° (P21/c). AH II can crystallise and exist both, as a solvent inclusion compound and as an unsolvated phase. The third polymorph, AH III, is exclusively obtained by desolvation of a carbon tetrachloride solvate. Theoretical calculations correctly estimated the experimental 0K stability order, confirmed that AH II can exist without solvents, gave access to the AH III structure, and identified that there exists a subtle balance between close packing and number of hydrogen bonding interactions in the solid state of anhydrous 4-AQ. Furthermore, the prevalence of void space and solvent inclusion in R3¯ structures is discussed. PMID:26726294

  9. Closed-form equations for the lift, drag, and pitching-moment coefficients of airfoil sections in subsonic flow

    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.

  10. Single-Camera Closed-Form Real-Time Needle Tracking for Ultrasound-Guided Needle Insertion.

    PubMed

    Najafi, Mohammad; Abolmaesumi, Purang; Rohling, Robert

    2015-10-01

    Many common needle intervention procedures are performed with ultrasound guidance because it is a flexible, cost-effective and widely available intra-operative imaging modality. In a needle insertion procedure with ultrasound guidance, real-time calculation and visualization of the needle trajectory can help to guide the choice of puncture site and needle angle to reach the target depicted in the ultrasound image. We found that it is feasible to calculate the needle trajectory with a single camera mounted directly on the ultrasound transducer by using the needle markings. Higher accuracy is achieved compared with other similar transducer-mounted needle trackers. We used an inexpensive, real-time and easy-to-use tracking method based on an automatic feature extraction algorithm and a closed-form method for pose estimation of the needle. The overall accuracy was 0.94 ± 0.46 mm. PMID:26215491

  11. An efficient closed-form design method for nearly perfect reconstruction of non-uniform filter bank.

    PubMed

    Kumar, A; Pooja, R; Singh, G K

    2016-03-01

    In this paper, an efficient closed form method for the design of multi-channel nearly perfect reconstruction of non-uniform filter bank with the prescribed stopband attenuation and channel overlapping is presented. In this method, the design problem of multi-channel non-uniform filter bank (NUFB) is considered as the design of a prototype filter whose magnitude response at quadrature frequency is 0.707, which is exploited for finding the optimum passband edge frequency through empirical formula instead of using single or multivariable optimization technique. Two main attributes used in assessing the performance of filter bank are peak reconstruction error (PRE) and computational time (CPU time). As compared to existing methods, this method is very simple and easy to implement for NUFBs. To implement this algorithm, a Matlab program has been developed, and several examples are presented to illustrate the performance of proposed method. PMID:26861726

  12. 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... FINANCIAL INFORMATION § 573.2 Model privacy form and examples. (a) Model privacy form. Use of the model... compliance with the notice content requirements of §§ 573.6 and 573.7 of this part, although use of the...

  13. 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... FINANCIAL INFORMATION § 573.2 Model privacy form and examples. (a) Model privacy form. Use of the model... compliance with the notice content requirements of §§ 573.6 and 573.7 of this part, although use of the...

  14. 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... FINANCIAL INFORMATION § 40.2 Model privacy form and examples. (a) Model privacy form. Use of the model... compliance with the notice content requirements of §§ 40.6 and 40.7 of this part, although use of the...

  15. 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... FINANCIAL INFORMATION § 573.2 Model privacy form and examples. (a) Model privacy form. Use of the model... compliance with the notice content requirements of §§ 573.6 and 573.7 of this part, although use of the...

  16. 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... FINANCIAL INFORMATION § 573.2 Model privacy form and examples. (a) Model privacy form. Use of the model... compliance with the notice content requirements of §§ 573.6 and 573.7 of this part, although use of the...

  17. 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... FINANCIAL INFORMATION § 573.2 Model privacy form and examples. (a) Model privacy form. Use of the model... compliance with the notice content requirements of §§ 573.6 and 573.7 of this part, although use of the...

  18. 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... FINANCIAL INFORMATION § 40.2 Model privacy form and examples. (a) Model privacy form. Use of the model... compliance with the notice content requirements of §§ 40.6 and 40.7 of this part, although use of the...

  19. 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... FINANCIAL INFORMATION § 40.2 Model privacy form and examples. (a) Model privacy form. Use of the model... compliance with the notice content requirements of §§ 40.6 and 40.7 of this part, although use of the...

  20. 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... FINANCIAL INFORMATION § 40.2 Model privacy form and examples. (a) Model privacy form. Use of the model... compliance with the notice content requirements of §§ 40.6 and 40.7 of this part, although use of the...

  1. 12 CFR Appendix A to Part 704 - Model Forms

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Model Forms A Appendix A to Part 704 Banks and Banking NATIONAL CREDIT UNION ADMINISTRATION REGULATIONS AFFECTING CREDIT UNIONS CORPORATE CREDIT UNIONS Pt. 704, App. A Appendix A to Part 704—Model Forms This appendix contains sample forms intended...

  2. On Fences, Forms and Mathematical Modeling

    ERIC Educational Resources Information Center

    Lege, Jerry

    2009-01-01

    The white picket fence is an integral component of the iconic American townscape. But, for mathematics students, it can be a mathematical challenge. Picket fences in a variety of styles serve as excellent sources to model constant, step, absolute value, and sinusoidal functions. "Principles and Standards for School Mathematics" (NCTM 2000)…

  3. Theoretical model for forming limit diagram predictions without initial inhomogeneity

    NASA Astrophysics Data System (ADS)

    Gologanu, Mihai; Comsa, Dan Sorin; Banabic, Dorel

    2013-05-01

    We report on our attempts to build a theoretical model for determining forming limit diagrams (FLD) based on limit analysis that, contrary to the well-known Marciniak and Kuczynski (M-K) model, does not assume the initial existence of a region with material or geometrical inhomogeneity. We first give a new interpretation based on limit analysis for the onset of necking in the M-K model. Considering the initial thickness defect along a narrow band as postulated by the M-K model, we show that incipient necking is a transition in the plastic mechanism from one of plastic flow in both the sheet and the band to another one where the sheet becomes rigid and all plastic deformation is localized in the band. We then draw on some analogies between the onset of necking in a sheet and the onset of coalescence in a porous bulk body. In fact, the main advance in coalescence modeling has been based on a similar limit analysis with an important new ingredient: the evolution of the spatial distribution of voids, due to the plastic deformation, creating weaker regions with higher porosity surrounded by sound regions with no voids. The onset of coalescence is precisely the transition from a mechanism of plastic deformation in both regions to another one, where the sound regions are rigid. We apply this new ingredient to a necking model based on limit analysis, for the first quadrant of the FLD and a porous sheet. We use Gurson's model with some recent extensions to model the porous material. We follow both the evolution of a homogeneous sheet and the evolution of the distribution of voids. At each moment we test for a potential change of plastic mechanism, by comparing the stresses in the uniform region to those in a virtual band with a larger porosity. The main difference with the coalescence of voids in a bulk solid is that the plastic mechanism for a sheet admits a supplementary degree of freedom, namely the change in the thickness of the virtual band. For strain ratios close to

  4. The effect of the model posture on the forming quality in the CNC incremental forming

    NASA Astrophysics Data System (ADS)

    Zhu, H.; Zhang, W.; Bai, J. L.; Yu, C.; Xing, Y. F.

    2015-12-01

    Sheet rupture caused by a sheet metal thickness non-uniformity persists in CNC (Computer Numerical Control) incremental forming. Because the forming half cone angle is determined by the orientation of the model to be formed, so is the sheet metal's uniformity. The finite element analysis models for the two kinds of the postures of the model were established, and the digital simulation was conducted by using the ANSYS/LA-DYNA software. The effect of the model's posture on the sheet thickness distribution and the sheet thickness thinning rate were studied by comparing the simulation results of two kinds of the finite elements analyzes.

  5. Contaminant Release from Residual Waste in Closed Single-Shell Tanks and Other Waste Forms Associated with the Tanks

    SciTech Connect

    Deutsch, William J.

    2008-01-17

    This chapter describes the release of contaminants from the various waste forms that are anticipated to be associated with closure of the single-shell tanks. These waste forms include residual sludge or saltcake that will remain in the tanks after waste retrieval. Other waste forms include engineered glass and cementitious materials as well as contaminated soil impacted by previous tank leaks. This chapter also describes laboratory testing to quantify contaminant release and how the release data are used in performance/risk assessments for the tank waste management units and the onsite waste disposal facilities. The chapter ends with a discussion of the surprises and lessons learned to date from the testing of waste materials and the development of contaminant release models.

  6. A Molecular Model for Lithium's Bioactive Form.

    PubMed

    Briggs, Katharine T; Giulian, Gary G; Li, Gong; Kao, Joseph P Y; Marino, John P

    2016-07-26

    Lithium carbonate, a drug for the treatment of bipolar disorder, provides mood stability to mitigate recurrent episodes of mania and/or depression. Despite its long-term and widespread use, the mechanism by which lithium acts to elicit these psychological changes has remained unknown. Using nuclear magnetic resonance (NMR) methods, in this study we characterized the association of lithium with adenosine triphosphate (ATP) and identified a bimetallic (Mg·Li) ATP complex. Lithium's affinity to form this complex was found to be relatively high (Kd ∼1.6 mM) compared with other monovalent cations and relevant, considering lithium dosing and physiological concentrations of Mg(2+) and ATP. The ATP·Mg·Li complex reveals, for the first time, to the best of our knowledge, that lithium can associate with magnesium-bound phosphate sites and then act to modulate purine receptor activity in neuronal cells, suggesting a molecular mode for in vivo lithium action. PMID:27463132

  7. 12 CFR Appendix A to Part 213 - Model Forms

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 2 2011-01-01 2011-01-01 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...

  8. 12 CFR Appendix A to Part 213 - Model Forms

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 2 2013-01-01 2013-01-01 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...

  9. 12 CFR Appendix A to Part 213 - Model Forms

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 2 2014-01-01 2014-01-01 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...

  10. 12 CFR Appendix A to Part 213 - Model Forms

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 2 2012-01-01 2012-01-01 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...

  11. 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...

  12. A Class of Pattern-Forming Models

    NASA Astrophysics Data System (ADS)

    Fife, P. C.; Kowalczyk, M.

    1999-12-01

    A general class of nonlinear evolution equations is described, which support stable spatially oscillatory steady solutions. These equations are composed of an indefinite self-adjoint linear operator acting on the solution plus a nonlinear function, a typical example of the latter being a double-well potential. Thus a Lyapunov functional exists. The linear operator contains a parameter ρ which could be interpreted as a measure of the pattern-forming tendency for the equation. Examples in this class of equations are an integrodifferential equation studied by Goldstein, Muraki, and Petrich and others in an activator-inhibitor context, and a class of fourth-order parabolic PDE's appearing in the literature in various physical connections and investigated rigorously by Coleman, Leizarowitz, Marcus, Mizel, Peletier, Troy, Zaslavskii, and others. The former example reduces to the real Ginzburg-Landau equation when ρ = 0 . The most complete results, including threshold results for the appearance of globally minimizing patterns and many other properties of the patterns themselves, are given for complex-valued solutions in one space variable. A complete linear stability analysis for all such sinusoidal solutions is also given; it extends the set of stable solutions considerably beyond the global minimizers. Other results, including threshold results and the existence of large amplitude patterns as well as of bifurcating solutions, are provided for real-valued solutions; these results are relatively independent of the number of space variables. Finally, a slightly different class of evolution equations is given for which no patterned global minimizer exists, but a sequence of patterned solutions exist whose instabilities (if they are unstable) become ever weaker and the fineness of the oscillation becomes ever more pronounced.

  13. 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%).

  14. Driver steering model for closed-loop steering function analysis

    NASA Astrophysics Data System (ADS)

    Bolia, Pratiksh; Weiskircher, Thomas; Müller, Steffen

    2014-05-01

    In this paper, a two level preview driver steering control model for the use in numerical vehicle dynamics simulation is introduced. The proposed model is composed of cascaded control loops: The outer loop is the path following layer based on potential field framework. The inner loop tries to capture the driver's physical behaviour. The proposed driver model allows easy implementation of different driving situations to simulate a wide range of different driver types, moods and vehicle types. The expediency of the proposed driver model is shown with the help of developed driver steering assist (DSA) function integrated with a conventional series production (Electric Power steering System with rack assist servo unit) system. With the help of the DSA assist function, the driver is prevented from over saturating the front tyre forces and loss of stability and controllability during cornering. The simulation results show different driver reactions caused by the change in the parameters or properties of the proposed driver model if the DSA assist function is activated. Thus, the proposed driver model is useful for the advanced driver steering and vehicle stability assist function evaluation in the early stage of vehicle dynamics handling and stability evaluation.

  15. 12 CFR Appendix A to Part 216 - Model Privacy Form

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 2 2012-01-01 2012-01-01 false Model Privacy Form A Appendix A to Part 216... CONSUMER FINANCIAL INFORMATION (REGULATION P) Pt. 216, App. A Appendix A to Part 216—Model Privacy Form A. The Model Privacy Form ER01DE09.007 ER01DE09.008 ER01DE09.009 ER01DE09.010 ER01DE09.011...

  16. 12 CFR Appendix A to Part 332 - Model Privacy Form

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 4 2011-01-01 2011-01-01 false Model Privacy Form A Appendix A to Part 332... PRIVACY OF CONSUMER FINANCIAL INFORMATION Pt. 332, App. A Appendix A to Part 332—Model Privacy Form A. The Model Privacy Form ER01DE09.014 ER01DE09.015 ER01DE09.016 ER01DE09.017 ER01DE09.018...

  17. 12 CFR Appendix A to Part 216 - Model Privacy Form

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 2 2011-01-01 2011-01-01 false Model Privacy Form A Appendix A to Part 216... CONSUMER FINANCIAL INFORMATION (REGULATION P) Pt. 216, App. A Appendix A to Part 216—Model Privacy Form A. The Model Privacy Form ER01DE09.007 ER01DE09.008 ER01DE09.009 ER01DE09.010 ER01DE09.011...

  18. 12 CFR Appendix A to Part 332 - Model Privacy Form

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 5 2013-01-01 2013-01-01 false Model Privacy Form A Appendix A to Part 332... PRIVACY OF CONSUMER FINANCIAL INFORMATION Pt. 332, App. A Appendix A to Part 332—Model Privacy Form A. The Model Privacy Form ER01DE09.014 ER01DE09.015 ER01DE09.016 ER01DE09.017 ER01DE09.018...

  19. 12 CFR Appendix A to Part 332 - Model Privacy Form

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 5 2014-01-01 2014-01-01 false Model Privacy Form A Appendix A to Part 332... PRIVACY OF CONSUMER FINANCIAL INFORMATION Pt. 332, App. A Appendix A to Part 332—Model Privacy Form A. The Model Privacy Form ER01DE09.014 ER01DE09.015 ER01DE09.016 ER01DE09.017 ER01DE09.018...

  20. 12 CFR Appendix A to Part 216 - Model Privacy Form

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 2 2013-01-01 2013-01-01 false Model Privacy Form A Appendix A to Part 216... CONSUMER FINANCIAL INFORMATION (REGULATION P) Pt. 216, App. A Appendix A to Part 216—Model Privacy Form A. The Model Privacy Form ER01DE09.007 ER01DE09.008 ER01DE09.009 ER01DE09.010 ER01DE09.011...

  1. 12 CFR Appendix A to Part 216 - Model Privacy Form

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 2 2014-01-01 2014-01-01 false Model Privacy Form A Appendix A to Part 216... CONSUMER FINANCIAL INFORMATION (REGULATION P) Pt. 216, App. A Appendix A to Part 216—Model Privacy Form A. The Model Privacy Form ER01DE09.007 ER01DE09.008 ER01DE09.009 ER01DE09.010 ER01DE09.011...

  2. 12 CFR Appendix A to Part 332 - Model Privacy Form

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 5 2012-01-01 2012-01-01 false Model Privacy Form A Appendix A to Part 332... PRIVACY OF CONSUMER FINANCIAL INFORMATION Pt. 332, App. A Appendix A to Part 332—Model Privacy Form A. The Model Privacy Form ER01DE09.014 ER01DE09.015 ER01DE09.016 ER01DE09.017 ER01DE09.018...

  3. Modeling abundances in star forming galaxies

    NASA Astrophysics Data System (ADS)

    Kobayashi, Chiaki

    2015-08-01

    Heavy elements are produced from various types of supernovae (and AGB stars). I first show that elemental abundances of extremely metal-poor stars are consistent not with pair-instability supernovae but with faint supernovae. Then I introduce subclasses of Type Ia supernovae such as SN 2002cx-like objects and sub-Chandrasekhar mass explosions. These "minor" supernovae are important in the early Universe or metal-poor systems such as dwarf spheroidal galaxies. With "major" chemical enrichment sources, I show cosmic chemical enrichment in our cosmological, hydrodynamical simulations. The feedback from active galactic nuclei (AGN) is also included with a new model for the formation of black holes motivated by the first star formation. AGN-driven outflows transport metals into the circumgalactic medium and the intergalactic medium. Nonetheless, the metallicity changes of galaxies are negligible, and the mass-metallicity relations, which are mainly generated by supernova feedback at the first star burst, are preserved. Within galaxies, metallicity radial gradients are produced, which can be affected by AGN feedback but are more sensitive to the merging histories. We find a weak correlation between the gradients and galaxy mass, which is consistent with available observations. These simulations also provide predictions of supernova/hypernova/GRB rates and the properties of their host galaxies.

  4. 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.

  5. Modeling and control for closed environment plant production systems.

    PubMed

    Fleisher, David H; Ting, K C

    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. PMID:12882224

  6. 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.

  7. Aging and Interdependence: A Theoretical Model for Close Relationships.

    ERIC Educational Resources Information Center

    Blieszner, Rosemary

    This paper demonstrates the utility of interdependence theory for understanding older persons' social relationships. Using friendship as an exemplary case, a model of expectations for and reactions to social exchanges is described. Exchanges which are perceived to be motivated by obligation are distinguished from those which are perceived to…

  8. 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).

  9. Closed form expressions for sheet resistance and mobility from Van-der-Pauw measurement on 90° symmetric devices with four arbitrary contacts

    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.

  10. Quantum quenches in the Luttinger model and its close relatives

    NASA Astrophysics Data System (ADS)

    Cazalilla, M. A.; Chung, Ming-Chiang

    2016-06-01

    A number of results on quantum quenches in the Luttinger and related models are surveyed with emphasis on post-quench correlations. For the Luttinger model and initial gaussian states, we discuss both sudden and smooth quenches of the interaction and the emergence of a steady state described by a generalized Gibbs ensemble. Comparisons between analytics and numerics, and the question of universality or lack thereof are also discussed. The relevance of the theoretical results to current and future experiments in the fields of ultracold atomic gases and mesoscopic systems of electrons is also briefly touched upon. Wherever possible, our approach is pedagogical and self-contained. This work is dedicated to the memory of our colleague Alejandro Muramatsu.

  11. Metallicities of Low Mass Inefficient Star Forming Dwarfs in S4G: Testing the Closed Box Paradigm

    NASA Astrophysics Data System (ADS)

    McKay, Myles; Stirewalt, Sabrina; Sheth, Kartik; de Swardt, Bonita; Walter, Donald

    2015-03-01

    Low mass dwarf galaxies are the most numerous extragalactic population in the Local Universe. Many gas-rich dwarfs appear to be forming stars less efficiently than normal, massive disk galaxies and are therefore important laboratories for the study of star formation. Here we present new observations using the Palomar Double Spectrograph for 19 dwarf galaxies from the S4G Survey with the lowest stellar to HI mass ratios. Preliminary analysis of the data indicate a wide range of metallicities which vary by as much as 0.5 dex in a single galaxy in different star forming regions. Such a dispersion in metallicities favors an open box model and the results suggest a varied star formation history, possibly induced via minor mergers and accretion. The National Radio Astronomy Observatory(NRAO), National Science Foundation(NSF), and the National Astronomy Consortium (NAC) Cville Cohort. Additional support was provided by NSF Awards AST-0750814 and AST-1358913 to South Carolina State University.

  12. Negative binomial models for abundance estimation of multiple closed populations

    USGS Publications Warehouse

    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.

  13. Modeling Hypercalciuria in the Genetic Hypercalciuric Stone-Forming Rat

    PubMed Central

    Frick, Kevin K.; Krieger, Nancy S.; Bushinsky, David A.

    2015-01-01

    Purpose of Review In this review we discuss how the Genetic Hypercalciuric Stone-Forming (GHS) rats, which closely model idiopathic hypercalciuria and stone formation in humans, provide insights into the pathophysiology and consequences of clinical hypercalciuria. Recent Findings Hypercalciuria in the GHS rats is due to a systemic dysregulation of calcium transport, as manifest by increased intestinal calcium absorption, increased bone resorption and decreased renal tubule calcium reabsorption. Increased levels of vitamin D receptor in intestine, bone and kidney appear to mediate these changes. The excess receptors are biologically active and increase tissue sensitivity to exogenous vitamin D. Bones of GHS rats have decreased bone mineral density (BMD) as compared with Sprague Dawley rats, and exogenous 1,25(OH)2D3 exacerbates the loss of BMD. Thiazide diuretics improve the BMD in GHS rats. Summary Studying GHS rats allows direct investigation of the effects of alterations in diet and utilization of pharmacologic therapy on hypercalciuria, urine supersaturation, stone formation and bone quality in ways that are not possible in humans. PMID:26050120

  14. Closed-form stochastic solutions for non-equilibrium dynamics and inheritance of cellular components over many cell divisions

    PubMed Central

    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

  15. A closed-form criterion for dislocation emission in nano-porous materials under arbitrary thermomechanical loading

    NASA Astrophysics Data System (ADS)

    Wilkerson, J. W.; Ramesh, K. T.

    2016-01-01

    Our traditional view of void nucleation is associated with interface debonding at second-phase particles. However, under extreme dynamic loading conditions second-phase particles may not necessarily be the dominant source of void nucleation sites. A few key experimental observations of laser spall surfaces support this assertion. Here, we describe an alternative mechanism to the traditional view, namely shock-induced vacancy generation and clustering followed by nanovoid growth mediated by dislocation emission. This mechanism only becomes active at very large stresses. It is therefore desirable to establish a closed-form criterion for the macroscopic stress required to activate dislocation emission in porous materials. Following an approach similar to Lubarda and co-workers, we derive the desired criterion by making use of stability arguments applied to the analytic solutions for the elastic interactions of dislocations and voids. Our analysis significantly extends that of Lubarda and co-workers by accounting for a more general stress state, finite porosity, surface tension, as well as temperature and pressure dependence. The resulting simple stress-based criterion is validated against a number of molecular dynamics simulations with favorable agreement.

  16. Closed-form analytical solutions for assessing the consequences of sea-level rise on unconfined sloping island aquifers

    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.

  17. Closed-Loop Brain Model of Neocortical Information-Based Exchange

    PubMed Central

    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

  18. A mathematical model on the closing and opening mechanism for Venus flytrap

    PubMed Central

    Xia, Lijin

    2010-01-01

    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. PMID:21460610

  19. The Simultaneous Modeling Technique: closing gaps in posteriors.

    PubMed

    Scolavino, Salvatore; Paolone, Gaetano; Orsini, Giovanna; Devoto, Walter; Putignano, Angelo

    2016-01-01

    Direct posterior restorations represent a widespread procedure in daily practice. Occlusal layering is often considered a complex task, generally not predictable and often requiring several occlusal adjustments. Moreover, direct posterior restorations are time consuming, as many small increments must be applied and cured individually to control shrinkage stress. Several authors have proposed different material layering techniques for posteriors. The authors of this article propose a simplified approach, which primarily aims to help the clinician perform quick, simple, predictable, and natural-looking occlusal modeling, reducing the need for occlusal adjustments. PMID:26835524

  20. Endogenous quasicycles and stochastic coherence in a closed endemic model

    NASA Astrophysics Data System (ADS)

    Ghose, Somdeb; Adhikari, R.

    2010-08-01

    We study the role of demographic fluctuations in typical endemics as exemplified by the stochastic SIRS model. The birth-death master equation of the model is simulated using exact numerics and analyzed within the linear noise approximation. The endemic fixed point is unstable to internal demographic noise, and leads to sustained oscillations. This is ensured when the eigenvalues (λ) of the linearized drift matrix are complex, which in turn, is possible only if detailed balance is violated. In the oscillatory state, the phases decorrelate asymptotically, distinguishing such oscillations from those produced by external periodic forcing. These so-called quasicycles are of sufficient strength to be detected reliably only when the ratio |Im(λ)/Re(λ)| is of order unity. The coherence or regularity of these oscillations show a maximum as a function of population size, an effect known variously as stochastic coherence or coherence resonance. We find that stochastic coherence can be simply understood as resulting from a nonmonotonic variation of |Im(λ)/Re(λ)| with population size. Thus, within the linear noise approximation, stochastic coherence can be predicted from a purely deterministic analysis. The non-normality of the linearized drift matrix, associated with the violation of detailed balance, leads to enhanced fluctuations in the population amplitudes.

  1. Endogenous quasicycles and stochastic coherence in a closed endemic model.

    PubMed

    Ghose, Somdeb; Adhikari, R

    2010-08-01

    We study the role of demographic fluctuations in typical endemics as exemplified by the stochastic SIRS model. The birth-death master equation of the model is simulated using exact numerics and analyzed within the linear noise approximation. The endemic fixed point is unstable to internal demographic noise, and leads to sustained oscillations. This is ensured when the eigenvalues (λ) of the linearized drift matrix are complex, which in turn, is possible only if detailed balance is violated. In the oscillatory state, the phases decorrelate asymptotically, distinguishing such oscillations from those produced by external periodic forcing. These so-called quasicycles are of sufficient strength to be detected reliably only when the ratio |Im(λ)/Re(λ)| is of order unity. The coherence or regularity of these oscillations show a maximum as a function of population size, an effect known variously as stochastic coherence or coherence resonance. We find that stochastic coherence can be simply understood as resulting from a nonmonotonic variation of |Im(λ)/Re(λ)| with population size. Thus, within the linear noise approximation, stochastic coherence can be predicted from a purely deterministic analysis. The non-normality of the linearized drift matrix, associated with the violation of detailed balance, leads to enhanced fluctuations in the population amplitudes. PMID:20866843

  2. 16 CFR Appendix A to Part 313 - Model Privacy Form

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Model Privacy Form A Appendix A to Part 313... FINANCIAL INFORMATION Pt. 313, App. A Appendix A to Part 313—Model Privacy Form A. The Model Privacy Form ER01DE09.035 ER01DE09.036 ER01DE09.037 ER01DE09.038 ER01DE09.039 ER01DE09.041 1. How the Model Privacy...

  3. 17 CFR Appendix A to Part 160 - Model Privacy Form

    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 A Appendix... Appendix A to Part 160—Model Privacy Form A. The Model Privacy Form ER28DE12.003 ER28DE12.004 ER28DE12.005 ER28DE12.006 ER28DE12.007 ER28DE12.008 ER28DE12.009 B. General Instructions 1. How the Model Privacy...

  4. 16 CFR Appendix A to Part 313 - Model Privacy Form

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Model Privacy Form A Appendix A to Part 313... FINANCIAL INFORMATION Pt. 313, App. A Appendix A to Part 313—Model Privacy Form A. The Model Privacy Form ER01DE09.035 ER01DE09.036 ER01DE09.037 ER01DE09.038 ER01DE09.039 ER01DE09.041 1. How the Model Privacy...

  5. 16 CFR Appendix A to Part 313 - Model Privacy Form

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Model Privacy Form A Appendix A to Part 313... FINANCIAL INFORMATION Pt. 313, App. A Appendix A to Part 313—Model Privacy Form A. The Model Privacy Form ER01DE09.035 ER01DE09.036 ER01DE09.037 ER01DE09.038 ER01DE09.039 ER01DE09.041 1. How the Model Privacy...

  6. 16 CFR Appendix A to Part 313 - Model Privacy Form

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 1 2012-01-01 2012-01-01 false Model Privacy Form A Appendix A to Part 313... FINANCIAL INFORMATION Pt. 313, App. A Appendix A to Part 313—Model Privacy Form A. The Model Privacy Form ER01DE09.035 ER01DE09.036 ER01DE09.037 ER01DE09.038 ER01DE09.039 ER01DE09.041 1. How the Model Privacy...

  7. 16 CFR Appendix A to Part 313 - Model Privacy Form

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 1 2011-01-01 2011-01-01 false Model Privacy Form A Appendix A to Part 313... FINANCIAL INFORMATION Pt. 313, App. A Appendix A to Part 313—Model Privacy Form A. The Model Privacy Form ER01DE09.035 ER01DE09.036 ER01DE09.037 ER01DE09.038 ER01DE09.039 ER01DE09.041 1. How the Model Privacy...

  8. Reexamining closed-form formulae for inclusive breakup: Application to deuteron- and 6Li-induced reactions

    NASA Astrophysics Data System (ADS)

    Lei, Jin; Moro, A. M.

    2015-10-01

    The problem of the calculation of inclusive breakup cross sections in nuclear reactions is reexamined. For that purpose, the post-form theory proposed by Ichimura, Austern, and Vincent [Phys. Rev. C 32, 431 (1985), 10.1103/PhysRevC.32.431] is revisited, and an alternative derivation of the nonelastic breakup part of the inclusive breakup is presented, making use of the coupled-channels optical theorem. Using the distorted-wave Born approximation (DWBA) version of this model, several applications to deuteron and 6Li reactions are presented and compared with available data. The validity of the zero-range approximation of the DWBA formula is also investigated by comparing zero-range with full finite-range calculations.

  9. The Dirac form factor predicts the Pauli form factor in the Endpoint Model

    NASA Astrophysics Data System (ADS)

    Dagaonkar, Sumeet K.; Jain, Pankaj; Ralston, John P.

    2016-07-01

    We compute the momentum-transfer dependence of the proton Pauli form factor F2 in the Endpoint overlap Model. We find the model correctly reproduces the scaling of the ratio of F2 with the Dirac form factor F1 observed at the Jefferson Laboratory. The calculation uses the leading-power, leading-twist Dirac structure of the quark light-cone wave function and the same endpoint dependence previously determined from the Dirac form factor F1. There are no parameters and no adjustable functions in the Endpoint Model's prediction for the scaling behavior of F2. The model's predicted momentum dependence of the ratio F2(Q2)/F1(Q2) is quite insensitive to the endpoint wave function, which explains why the observed ratio scales like 1 / Q down to rather low momentum transfers. We also fit the magnitude of this ratio by adjusting the parameters of the wave function. The Endpoint Model appears to be the only comprehensive model consistent with all form factor information as well as reproducing fixed-angle proton-proton scattering at large momentum transfer. Any one of the processes is capable of predicting the others.

  10. Emotional closeness to parents and grandparents: A moderated mediation model predicting adolescent adjustment.

    PubMed

    Attar-Schwartz, Shalhevet

    2015-09-01

    Warm and emotionally close relationships with parents and grandparents have been found in previous studies to be linked with better adolescent adjustment. The present study, informed by Family Systems Theory and Intergenerational Solidarity Theory, uses a moderated mediation model analyzing the contribution of the dynamics of these intergenerational relationships to adolescent adjustment. Specifically, it examines the mediating role of emotional closeness to the closest grandparent in the relationship between emotional closeness to a parent (the offspring of the closest grandparent) and adolescent adjustment difficulties. The model also examines the moderating role of emotional closeness to parents in the relationship between emotional closeness to grandparents and adjustment difficulties. The study was based on a sample of 1,405 Jewish Israeli secondary school students (ages 12-18) who completed a structured questionnaire. It was found that emotional closeness to the closest grandparent was more strongly associated with reduced adjustment difficulties among adolescents with higher levels of emotional closeness to their parents. In addition, adolescent adjustment and emotional closeness to parents was partially mediated by emotional closeness to grandparents. Examining the family conditions under which adolescents' relationships with grandparents is stronger and more beneficial for them can help elucidate variations in grandparent-grandchild ties and expand our understanding of the mechanisms that shape child outcomes. PMID:26237053

  11. A Model for Short Gamma-Ray Bursts: Heated Neutron Stars in Close Binary Systems

    SciTech Connect

    Salmonson, J.D.; Wilson, J.R.

    2001-12-17

    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 ({approx} 10{sup 53} ergs/sec). A fraction of these neutrinos will annihilate to form an e{sup +}e{sup -} pair plasma wind which will, in turn, expand and recombine to photons which make the gamma-ray burst. We study neutrino annihilation and show that a substantial fraction ({approx}1/2) of energy deposited comes from inter-star neutrinos, where each member of the neutrino pair originates from each neutron star. Thus, in addition to the annihilation of neutrinos blowing off of a single star, we have a new source of baryon free energy that is deposited between the stars. To model the e{sup +}e{sup -} pair plasma wind between stars, we do three-dimensional relativistic numerical hydrodynamic calculations. Preliminary results are also presented of new, fully general relativistic calculations of gravitationally attracting stars falling from infinity with no angular momentum. These simulations exhibit a compression effect.

  12. Surrogate POD models for building forming limit diagrams of parameterized sheet metal forming applications

    NASA Astrophysics Data System (ADS)

    Hamdaoui, M.; Le Quilliec, Guénhaël; Breitkopf, Piotr; Villon, Pierre

    2013-05-01

    The aim of this work is to present a surrogate POD (Proper Orthogonal Decomposition) approach for building forming limit diagrams at minimum cost for parameterized sheet metal formed work-pieces. First, a Latin Hypercube Sampling is performed on the design parameter space. Then, at each design site, displacement fields are computed using the popular open-source finite element software Code_Aster. Then, the method of snapshots is used for POD mode determination. POD coefficients are interpolated using kriging. Furthermore, an error analysis of the surrogate POD model is performed on a validation set. It is shown that on the considered use case the accuracy of the surrogate POD model is excellent for the representation of finite element displacement fields. The validated surrogate POD model is then used to build forming limit diagrams (FLD) for any design parameter to assess the quality of stamped metal sheets. Using the surrogate POD model, the Green-Lagrange strain tensor is derived, then major and minor principal deformations are determined at Gauss points for each mesh element. Furthermore, a signed distance between the forming limit curve in rupture and the obtained cloud of points in the plane (ɛ2, ɛ1) is computed to assess the quality of the formed workpiece. The minimization of this signed distance allows determining the safest design for the chosen use case.

  13. Closed loop models for analyzing the effects of simulator characteristics. [pilot performance/workload prediction

    NASA Technical Reports Server (NTRS)

    Baron, S.; Muralidharan, R.; Kleinman, D.

    1978-01-01

    The optimal control model (OCM) 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 multi-rate simulation in which the optimal control model 'simulates' the pilot. Both models predict that simulator characteristics can have significant effects on performance and workload.

  14. Closed loop models for analyzing the effects of simulator characteristics. [digital simulation of human operators

    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.

  15. 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.

  16. Form factors in SU(3)-invariant integrable models

    NASA Astrophysics Data System (ADS)

    Belliard, S.; Pakuliak, S.; Ragoucy, E.; Slavnov, N. A.

    2013-04-01

    We study SU(3)-invariant integrable models solvable by a nested algebraic Bethe ansatz. We obtain determinant representations for form factors of diagonal entries of the monodromy matrix. This representation can be used for the calculation of form factors and correlation functions of the XXX SU(3)-invariant Heisenberg chain.

  17. Relativistic quark model for the Omega- electromagnetic form factors

    SciTech Connect

    G. Ramalho, K. Tsushima, Franz Gross

    2009-08-01

    We compute the Omega- electromagnetic form factors and the decuplet baryon magnetic moments using a quark model application of the Covariant Spectator Theory. Our predictions for the Omega- electromagnetic form factors can be tested in the future by lattice QCD simulations at the physical strange quark mass.

  18. Submission Form for Peer-Reviewed Cancer Risk Prediction Models

    Cancer.gov

    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.

  19. 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...

  20. 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.

  1. 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.

  2. 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.

  3. Cracks and blisters formed close to a silicon wafer surface by He-H co-implantation at low energy

    SciTech Connect

    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.

  4. 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.

  5. Periodic and Aperiodic Close Packing: A Spontaneous Hard-Sphere Model.

    ERIC Educational Resources Information Center

    van de Waal, B. W.

    1985-01-01

    Shows how to make close-packed models from balloons and table tennis balls to illustrate structural features of clusters and organometallic cluster-compounds (which are of great interest in the study of chemical reactions). These models provide a very inexpensive and tactile illustration of the organization of matter for concrete operational…

  6. Analytic Model For Estimation Of Cold Bulk Metal Forming Simulations

    SciTech Connect

    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.

  7. 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.

  8. Fisheries Closed Areas Strengthen Scallop Larval Settlement and Connectivity Among Closed Areas and Across International Open Fishing Grounds: A Model Study

    NASA Astrophysics Data System (ADS)

    Davies, Kimberley T. A.; Gentleman, W. C.; DiBacco, C.; Johnson, C. L.

    2015-09-01

    This study examined whether a measured increase in average body size of adult sea scallops inside three fishery closed areas on Georges Bank (GB), United States (US), was sufficient to increase larval supply to closed areas and open fishing areas in both US and Canadian areas of the Bank. The effects of adult scallop density-at-size and fecundity-at-size on egg production were compared among open and closed fishery areas, countries, and time periods before and after the closed areas were established. Estimated egg production was then used to define spawning conditions in a coupled biological-physical larval tracking model that simulated larval development, mortality, and dispersal. Results showed that order of magnitude increases in larval settlement after closure were facilitated by increases in size-dependant egg production inside and dispersal from Closed Areas I and II, but not Nantucket Lightship Closed Area. The distributions of both egg production and larval settlement became more uniform across the Bank, causing the relative contribution of Canadian larvae to US scallop aggregations to decrease after establishment of Closed Areas I and II. Decreases in small and medium-sized scallop density in Canada and decreases in large scallops over the US-Southern Flank after closure caused local declines in egg production but were not sufficient to negatively affect larval settlement at the regional scale. Our model suggests that the establishment of fishery closed areas on GB considerably strengthened larval supply and settlement within and among several adult scallop aggregations.

  9. Modelling of Superplastic Forming of AZ31 Magnesium Alloy

    SciTech Connect

    Giuliano, G.

    2011-01-17

    In this study the constitutive equation of the superplastic AZ31 magnesium-based alloy is modelled by the power law relationship between the stress, the strain and the strain-rate and an accurate procedure for determining the constants of the material is presented. Moreover, the problem of optimizing the pressure-time load curve of a free forming process is investigated and resolved by means of a pressure jump forming process. The experimental tests, carried out to support the finite-element modelling, have shown good agreement between the numerical results and the experimental data.

  10. 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.

  11. The model of the variable speed constant frequency closed-loop system operating in generating state

    NASA Astrophysics Data System (ADS)

    Ding, Daohong

    1986-10-01

    The variable speed constant frequency (USCF) electrical power system is a new type of aircraft power supply, which contains an alternating generator and a cycloconverter. This sums up the work of the cycloconverter and obtains four fundamental classes of circuit construction of the closed-loop system, which have twelve operating models. A mathematical model for each fundamental class of the circuit construction is introduced. These mathematical models can be used in digital simulation.

  12. 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

  13. Challenges in Modeling the Degradation of Ceramic Waste Forms

    SciTech Connect

    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.

  14. Closed-form approximation and numerical validation of the influence of van der Waals force on electrostatic cantilevers at nano-scale separations

    NASA Astrophysics Data System (ADS)

    Ramezani, Asghar; Alasty, Aria; Akbari, Javad

    2008-01-01

    In this paper the two-point boundary value problem (BVP) of the cantilever deflection at nano-scale separations subjected to van der Waals and electrostatic forces is investigated using analytical and numerical methods to obtain the instability point of the beam. In the analytical treatment of the BVP, the nonlinear differential equation of the model is transformed into the integral form by using the Green's function of the cantilever beam. Then, closed-form solutions are obtained by assuming an appropriate shape function for the beam deflection to evaluate the integrals. In the numerical method, the BVP is solved with the MATLAB BVP solver, which implements a collocation method for obtaining the solution of the BVP. The large deformation theory is applied in numerical simulations to study the effect of the finite kinematics on the pull-in parameters of cantilevers. The centerline of the beam under the effect of electrostatic and van der Waals forces at small deflections and at the point of instability is obtained numerically. In computing the centerline of the beam, the axial displacement due to the transverse deformation of the beam is taken into account, using the inextensibility condition. The pull-in parameters of the beam are computed analytically and numerically under the effects of electrostatic and/or van der Waals forces. The detachment length and the minimum initial gap of freestanding cantilevers, which are the basic design parameters, are determined. The results of the analytical study are compared with the numerical solutions of the BVP. The proposed methods are validated by the results published in the literature.

  15. Closed-form approximation and numerical validation of the influence of van der Waals force on electrostatic cantilevers at nano-scale separations.

    PubMed

    Ramezani, Asghar; Alasty, Aria; Akbari, Javad

    2008-01-01

    In this paper the two-point boundary value problem (BVP) of the cantilever deflection at nano-scale separations subjected to van der Waals and electrostatic forces is investigated using analytical and numerical methods to obtain the instability point of the beam. In the analytical treatment of the BVP, the nonlinear differential equation of the model is transformed into the integral form by using the Green's function of the cantilever beam. Then, closed-form solutions are obtained by assuming an appropriate shape function for the beam deflection to evaluate the integrals. In the numerical method, the BVP is solved with the MATLAB BVP solver, which implements a collocation method for obtaining the solution of the BVP. The large deformation theory is applied in numerical simulations to study the effect of the finite kinematics on the pull-in parameters of cantilevers. The centerline of the beam under the effect of electrostatic and van der Waals forces at small deflections and at the point of instability is obtained numerically. In computing the centerline of the beam, the axial displacement due to the transverse deformation of the beam is taken into account, using the inextensibility condition. The pull-in parameters of the beam are computed analytically and numerically under the effects of electrostatic and/or van der Waals forces. The detachment length and the minimum initial gap of freestanding cantilevers, which are the basic design parameters, are determined. The results of the analytical study are compared with the numerical solutions of the BVP. The proposed methods are validated by the results published in the literature. PMID:21730532

  16. 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.

  17. CTAB/water/chloroform reverse micelles: a closed or open association model?

    PubMed

    Klíčová, L'ubica; Sebej, Peter; Štacko, Peter; Filippov, Sergey K; Bogomolova, Anna; Padilla, Marc; Klán, Petr

    2012-10-30

    The micellization of cetyltrimethylammonium bromide (CTAB) in chloroform in the presence of water was examined. Three scenarios of the reverse micelle formation, the closed, open and Eicke's association models, were considered in the interpretation of the experimental data. The growth of the aggregates was observed through the changes of NMR signals of associated water, probing the microenvironment of the premicellar aggregates and the interior of reverse micelles. This technique if combined with isothermal titration calorimetry (ITC) revealed that hydrated surfactant premicellar aggregates are already present at ∼6 mM CTAB. NMR, ITC and conductometry were used to determine the critical micelle concentration (cmc) to be ∼40 mM CTAB. It is suggested that the variation of the cmc values reflects the fact that the NMR analysis indicated the beginning of the reverse micelle formation, whereas conductometry and ITC measurements provided the upper limit and an average value of a so-called apparent cmc, respectively. The cmc values were found to be unaffected by the water content. The presence of reverse micelles, the existence of multiple equilibria, and high polydispersity of the samples were evidenced by DOSY NMR spectroscopy. As a result, we validated Eicke's association model, according to which cyclic inverse micelles are formed by a structural reorganization of linear associates within a narrow concentration range, called the apparent cmc. New experimental results have also been gained for micellization of cetyltrimethylammonium chloride (CTAC) in chloroform in the presence of water; a similar mechanism of reverse micelle formation has been suggested. PMID:23072317

  18. A Simple Multistage Closed-(Box+Reservoir) Model of Chemical Evolution

    NASA Astrophysics Data System (ADS)

    Caimmi, R.

    2011-12-01

    Simple closed-box (CB) models of chemical evolution are extended on two respects, namely (i) simple closed-(box+reservoir) (CBR) models allowing gas outflow from the box into the reservoir (Hartwick 1976) or gas inflow into the box from the reservoir (Caimmi 2007) with rate proportional to the star formation rate, and (ii) simple multistage closed-(box+reservoir) (MCBR) models allowing different stages of evolution characterized by different inflow or outflow rates. The theoretical differential oxygen abundance distribution (TDOD) predicted by the model maintains close to a continuous broken straight line. An application is made where a fictitious sample is built up from two distinct samples of halo stars and taken as representative of the inner Galactic halo. The related empirical differential oxygen abundance distribution (EDOD) is represented, to an acceptable extent, as a continuous broken line for two viable [O/H]-[Fe/H] empirical relations. The slopes and the intercepts of the regression lines are determined, and then used as input parameters to MCBR models. Within the errors (mpsigma), regression line slopes correspond to a large inflow during the earlier stage of evolution and to low or moderate outflow during the subsequent stages. A possible inner halo - outer (metal-poor) bulge connection is also briefly discussed. Quantitative results cannot be considered for applications to the inner Galactic halo, unless selection effects and disk contamination are removed from halo samples, and discrepancies between different oxygen abundance determination methods are explained.

  19. On open and closed field line regions in Tsyganenko's field model and their possible associations with horse collar auroras

    SciTech Connect

    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.

  20. A dimensionally-heterogeneous closed-loop model for the cardiovascular system and its applications.

    PubMed

    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. PMID:22902782

  1. Status of ceramic waste form degradation and radionuclide release modeling.

    SciTech Connect

    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.

  2. A unified model for subaqueous bed form dynamics

    NASA Astrophysics Data System (ADS)

    Jerolmack, Douglas J.; Mohrig, David

    2005-12-01

    Bed form evolution remains dynamic even in the special case of steady, uniform flow. Data from the sandy, braided North Loup River, Nebraska, show that roughness features on the channel bottom display a statistical steady state and robust scaling that are maintained through the collective interactions of transient (short-lived) bed forms. Motivated by such field data, and laboratory observations of bed form growth, we develop a nonlinear stochastic surface evolution model for the topography of bed load dominated sandy rivers in which instantaneous sediment flux explicitly depends on local elevation and slope. This model quantitatively reproduces laboratory observations of initial growth and saturation of bed forms from a flat surface, and also generates long-term dynamical behavior characteristic of natural systems. We argue that the variability in geometry and kinematics of bed forms in steady flow, and the existence of roughness at all wavelengths up to the largest dunes, are a consequence of the nonlinear relationship between sediment flux and topography, subject to noise.

  3. Mathematical model of a closed hot air engine cycle using MATLAB Simulink

    NASA Astrophysics Data System (ADS)

    Oršanský, Pavol; Ftorek, Branislav; Durčanský, Peter

    2014-08-01

    In our work we present a model of a closed hot air engine, which we simulate in MATLAB®Simulink® environment. That gives us many opportunities of investigating the influence of extreme demanding conditions on the stability and functionality of the device. We were also able to try the conditions that would real device cannot resist as high temperature or pressure.

  4. Existence of standard models of conic fibrations over non-algebraically-closed fields

    SciTech Connect

    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.

  5. 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…

  6. Bed form dynamics in distorted lightweight scale models

    NASA Astrophysics Data System (ADS)

    Aberle, Jochen; Henning, Martin; Ettmer, Bernd

    2016-04-01

    The adequate prediction of flow and sediment transport over bed forms presents a major obstacle for the solution of sedimentation problems in alluvial channels because bed forms affect hydraulic resistance, sediment transport, and channel morphodynamics. Moreover, bed forms can affect hydraulic habitat for biota, may introduce severe restrictions to navigation, and present a major problem for engineering structures such as water intakes and groynes. The main body of knowledge on the geometry and dynamics of bed forms such as dunes originates from laboratory and field investigations focusing on bed forms in sand bed rivers. Such investigations enable insight into the physics of the transport processes, but do not allow for the long term simulation of morphodynamic development as required to assess, for example, the effects of climate change on river morphology. On the other hand, this can be achieved through studies with distorted lightweight scale models allowing for the modification of the time scale. However, our understanding of how well bed form geometry and dynamics, and hence sediment transport mechanics, are reproduced in such models is limited. Within this contribution we explore this issue using data from investigations carried out at the Federal Waterways and Research Institute in Karlsruhe, Germany in a distorted lightweight scale model of the river Oder. The model had a vertical scale of 1:40 and a horizontal scale of 1:100, the bed material consisted of polystyrene particles, and the resulting dune geometry and dynamics were measured with a high spatial and temporal resolution using photogrammetric methods. Parameters describing both the directly measured and up-scaled dune geometry were determined using the random field approach. These parameters (e.g., standard deviation, skewness, kurtosis) will be compared to prototype observations as well as to results from the literature. Similarly, parameters describing the lightweight bed form dynamics, which

  7. A classical model for closed-loop diagrams of binary liquid mixtures

    SciTech Connect

    Schnitzler, J.v.; Prausnitz, J.M. |

    1994-03-01

    A classical lattice model for closed-loop temperature-composition phase diagrams has been developed. It considers the effect of specific interactions, such as hydrogen bonding, between dissimilar components. This van Laar-type model includes a Flory-Huggins term for the excess entropy of mixing. It is applied to several liquid-liquid equilibria of nonelectrolytes, where the molecules of the two components differ in size. The model is able to represent the observed data semi-quantitatively, but in most cases it is not flexible enough to predict all parts of the closed loop quantitatively. The ability of the model to represent different binary systems is discussed. Finally, attention is given to a correction term, concerning the effect of concentration fluctuations near the upper critical solution temperature.

  8. Model-Driven Safety Analysis of Closed-Loop Medical Systems

    PubMed Central

    Pajic, Miroslav; Mangharam, Rahul; Sokolsky, Oleg; Arney, David; Goldman, Julian; Lee, Insup

    2013-01-01

    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. PMID:24177176

  9. Suppressing epileptic activity in a neural mass model using a closed-loop proportional-integral controller.

    PubMed

    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

  10. Suppressing epileptic activity in a neural mass model using a closed-loop proportional-integral controller

    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.

  11. Suppressing epileptic activity in a neural mass model using a closed-loop proportional-integral controller

    PubMed Central

    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

  12. 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.

  13. On closed form expressions for the singular-value decomposition of an orientational Jacobian and its application to a motion simulator

    SciTech Connect

    Roberts, R.G.; Repperger, D.W.

    1999-01-01

    This article presents some results on the closed-form, singular-value decomposition of the orientational Jacobian for three- and four-degree-of-freedom wristlike mechanisms. These results are used to study the kinematics of a centrifuge simulator, and to determine the centrifuge`s limitations in achieving maximum angular velocities. Also, the issue of fault tolerance for a redundant wrist is addressed.

  14. 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.

  15. 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.

  16. 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.

  17. Octet Baryon Electromagnetic Form Factors in a Relativistic Quark Model

    SciTech Connect

    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.

  18. Formulation and experimental evaluation of closed-form control laws for the rapid maneuvering of reactor neutronic power

    SciTech Connect

    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.

  19. Baryon octet electromagnetic form factors in a confining NJL model

    NASA Astrophysics Data System (ADS)

    Carrillo-Serrano, Manuel E.; Bentz, Wolfgang; Cloët, Ian C.; Thomas, Anthony W.

    2016-08-01

    Electromagnetic form factors of the baryon octet are studied using a Nambu-Jona-Lasinio model which utilizes the proper-time regularization scheme to simulate aspects of colour confinement. In addition, the model also incorporates corrections to the dressed quarks from vector meson correlations in the t-channel and the pion cloud. Comparison with recent chiral extrapolations of lattice QCD results shows a remarkable level of consistency. For the charge radii we find the surprising result that rEp < rEΣ+ and | rEn | < | rEΞ0 |, whereas the magnetic radii have a pattern largely consistent with a naive expectation based on the dressed quark masses.

  20. Mechanical properties and modeling of seal-forming lithologies

    SciTech Connect

    1998-03-01

    This proposal includes: (1) a summary of research accomplished over the last three year period on the mechanical properties and modeling of shales and rocksalt, two lithologies that deform readily and form seals to major petroleum and gas reservoirs, and (2) a renewal proposal to extend both the experimental and modeling studies and to integrate the two, incorporating both rocksalt and shale flow laws to investigate the development of structural traps. The numerical modeling efforts to simulate the development of salt structures and the experimental efforts to determine a rate-dependent deformation law for shale have proceeded somewhat independently as well-determined rheologies for rocksalt were available at the outset of the project that could be incorporated into the models, whereas well-constrained rate-dependent constitutive relationships for shales were unavailable. However, both studies have been carried out with a common goal of examining their roles in the development of structural traps.

  1. Finite-lattice form factors in free-fermion models

    NASA Astrophysics Data System (ADS)

    Iorgov, N.; Lisovyy, O.

    2011-04-01

    We consider the general {Z}_2 -symmetric free-fermion model on the finite periodic lattice, which includes as special cases the Ising model on the square and triangular lattices and the {Z}_n -symmetric BBS τ(2)-model with n = 2. Translating Kaufman's fermionic approach to diagonalization of Ising-like transfer matrices into the language of Grassmann integrals, we determine the transfer matrix eigenvectors and observe that they coincide with the eigenvectors of a square lattice Ising transfer matrix. This allows us to find exact finite-lattice form factors of spin operators for the statistical model and the associated finite-length quantum chains, of which the most general is equivalent to the XY chain in a transverse field.

  2. A mouse model of weight-drop closed head injury: emphasis on cognitive and neurological deficiency.

    PubMed

    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

    2016-04-01

    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

  3. A mouse model of weight-drop closed head injury: emphasis on cognitive and neurological deficiency

    PubMed Central

    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

  4. 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.

  5. Closed form solution for a conductive-convective-radiative annular fin with multiple nonlinearities and its inverse analysis

    NASA Astrophysics Data System (ADS)

    Ranjan, Rajiv; Mallick, Ashis; Prasad, Dilip K.

    2016-07-01

    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.

  6. An approach to modeling a kinematically redundant dual manipulator closed chain system using pseudovelocities

    SciTech Connect

    Unseren, M.A.

    1996-05-01

    The paper discusses the problem of resolving the kinematic redundancy in the closed chain formed when two redundant manipulators mutually lift a rigid body object. The positional degrees of freedom (DOF) in the closed chain are parameterized by a set of independent variables termed pseudovelocities. Due to the redundancy there are more DOF and thus more pseudovelocities than are required to specify the motion of the held object. The additional ``redundant`` pseudovelocities are used to minimize the distance between the vector of unknown joint velocities and a vector of ``corrective`` joint velocities in a Euclidean norm sense. This leads to an optimal solution for the joint velocities as a linear function of the Cartesian object velocities and the corrective velocities. The problem of determining the corrective velocities to avoid collisions of the links with a wall located in the workspace and to avoid joint range limits is illustrated by an example of two redundant planar revolute joint manipulators mutually lifting a rigid object.

  7. Mechanical properties and modeling of seal-forming lithologies

    SciTech Connect

    Kronenberg, A.K.; Russell, J.E.; Carter, N.L.; Mazariegos, R.; Shea, W.T.

    1991-03-01

    The goal of this research is to evaluate the roles of deformation and the occurrence of weak sedimentary lithologies subjected to gravitational loads in shaping conventional and unconventional oil and gas reservoirs. Two sedimentary lithologies that influence the geometries, physical properties, and heterogeneities of oil and gas reservoirs are shale and rocksalt. Both form effect barriers to the flow and communication of petroleum and gas and, in many cases, form the seals to major reservoirs due to their low permeabilities. Both are actively deformed in depositional environments due to their low strengths relative to gravitational loads applied. Thus, the shapes of seal-forming units, and the nature of fractures and faults that may breach them depend upon either the mechanical properties of shale or those of salt, and the loading histories to which they have been subjected. Deformed shales may, in addition, serve as unconventional reservoirs of gas if open fractures within them provide sufficient porosity. The fracture and flow properties of shales are not well constrained, and the authors are currently investigating these properties experimentally. The rheology of rocksalt, on the other hand, is well known and they believe that the time is right to apply the experimentally constrained constitutive relations for rocksalt to deformations in the Earth. Efforts are continuing on modeling fracture anisotropy and the authors have examined simple, two-mica models to evaluate the mechanical interactions they proposed for gneiss and mica-poor schists. Brief summaries of the progress and results to date for (1) the mechanical properties of schist, (2) a two-mica model of fracture anisotropy, (3) deformation of shale, and (4) modeling of salt and shale tectonics of the northern Gulf of Mexico are given in the following sections. 35 refs., 33 figs., 1 tab.

  8. Star-forming filaments in warm dark matter models

    NASA Astrophysics Data System (ADS)

    Gao, Liang; Theuns, Tom; Springel, Volker

    2015-06-01

    We performed a hydrodynamical cosmological simulation of the formation of a Milky Way-like galaxy in a warm dark matter (WDM) cosmology. Smooth and dense filaments, several comoving mega parsec long, form generically above z ˜ 2 in this model. Atomic line cooling allows gas in the centres of these filaments to cool to the base of the cooling function, resulting in a very striking pattern of extended Lyman-limit systems (LLSs). Observations of the correlation function of LLSs might hence provide useful limits on the nature of the dark matter. We argue that the self-shielding of filaments may lead to a thermal instability resulting in star formation. We implement a sub-grid model for this, and find that filaments rather than haloes dominate star formation until z ˜ 6, although this depends on how stars form in WDM. Reionization decreases the gas density in filaments, and the more usual star formation in haloes dominates below z ˜ 6, although star formation in filaments continues until z = 2. 15 per cent of the stars of the z = 0 galaxy formed in filaments. At higher redshift, these stars give galaxies a stringy appearance, which, if observed, might be a strong indication that the dark matter is warm.

  9. Specific initiation of replication at the right-end telomere of the closed species of minute virus of mice replicative-form DNA.

    PubMed Central

    Baldauf, A Q; Willwand, K; Mumtsidu, E; Nüesch, J P; Rommelaere, J

    1997-01-01

    We have developed an in vitro system that supports the replication of natural DNA templates of the autonomous parvovirus minute virus of mice (MVM). MVM virion DNA, a single-stranded molecule bracketed by short, terminal, self-complementary sequences, is converted into double-stranded replicative-form (RF) DNA when incubated in mouse A9 fibroblast extract. The 3' end of the newly synthesized complementary strand is ligated to the right-end hairpin of the virion strand, resulting in the formation of a covalently closed RF (cRF) molecule as the major conversion product. cRF DNA is not further replicated in A9 cell extract alone. On addition of purified MVM nonstructural protein NS1 expressed from recombinant baculoviruses or vaccinia viruses, cRF DNA is processed into a right-end (5' end of the virion strand) extended form (5'eRF). This is indicative of NS1-dependent nicking of the right-end hairpin at a distinct position, followed by unfolding of the hairpin and copying of the terminal sequence. In contrast, no resolution of the left-end hairpin can be detected in the presence of NS1. In the course of the right-end nicking reaction, NS1 gets covalently attached to the right-end telomere of the DNA product, as shown by immunoprecipitation with NS1-specific antibodies. The 5'eRF product is the target for additional rounds of NS1-induced nicking and displacement synthesis at the right end, arguing against the requirement of the hairpin structure for recognition of the DNA substrate by NS1. Further processing of the 5'eRF template in vitro leads to the formation of dimeric RF (dRF) DNA in a left-to-left-end configuration, presumably as a result of copying of the whole molecule by displacement synthesis initiated at the right-end telomere. Formation of dRF DNA is highly stimulated by NS1. The experimental results presented in this report support various assumptions of current models of parvovirus DNA replication and provide new insights into the replication functions of

  10. 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.

  11. Modeling analysis of bubble flow regime in a closed two-phase thermosyphon

    NASA Astrophysics Data System (ADS)

    Tang, Zhi-Wei; Han, Ya-Fang; Liu, Ai-Jie; Song, Wei-Gang

    2011-12-01

    Predictions of the operating liquid level in the evaporator of a closed two-phase thermosyphon (gravity heat pipe) are given throughout a simplified analysis which takes the influence of the dimension and condensation heat transfer in the condenser of the heat pipe into account. In order to verify the accuracy of our model comparison of the present study with some published results is made by means of computational examples.

  12. General, Closed-Form Expressions for the Time-Domain Surface Impedances of a Homogeneous, Lossy Half-Space

    SciTech Connect

    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.

  13. Closed-loop control of epileptiform activities in a neural population model using a proportional-derivative controller

    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.

  14. Mechanical properties and modeling of seal-forming lithologies

    SciTech Connect

    Kronenberg, A.K.; Russell, J.E.; Carter, N.L.; Ibanez, W.; Mazariegos, R.

    1992-04-01

    Both rocksalt and shale lithologies are actively deformed in response to gravitational loads associated with deposition, and both form effective seals to petroleum and natural gas. Thus, the shapes of seal-forming units, and the nature of fractures and faults that may breach them depend upon either the mechanical properties of salt or those of shale, and the loading histories to which they have been subjected. The objectives of this research include the determination of the mechanical properties under controlled conditions of well-characterized shales, and the numerical modeling of rocksalt (and eventually shale) formations using laboratory-based rheologies. Progress has been made towards these goals over this project period, both in our experimental program on shale deformation and model development for the growth of salt diapirs. The mechanical anisotropy of an illite-bearing shale from Louisiana has been determined and related to the preferred orientation and distribution of clays. Its strength in the absence of pore fluids has been determined at confining pressures of up to 250 MPa and at high pressure we have investigated the effects of deformation rate and temperature. A numerical finite difference code has been developed to solve the incompressible Navier-Stokes equations and validated using a two- layer linear viscous model for which analytic solutions are available. Although the code has only been validated for the linear viscous case, it is capable of solving for highly nonlinear constitutive laws as well as solving for arbitrary interfaces between the salt and overburden.

  15. Various forms of indexing HDMR for modelling multivariate classification problems

    SciTech Connect

    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.

  16. Various forms of indexing HDMR for modelling multivariate classification problems

    NASA Astrophysics Data System (ADS)

    Aksu, ćaǧrı; Tunga, M. Alper

    2014-12-01

    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.

  17. 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.

  18. Microstructure based model for sound absorption predictions of perforated closed-cell metallic foams.

    PubMed

    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. PMID:20968350

  19. Novel Model of Frontal Impact Closed Head Injury in the Rat

    PubMed Central

    Kilbourne, Michael; Kuehn, Reed; Tosun, Cigdem; Caridi, John; Keledjian, Kaspar; Bochicchio, Grant; Scalea, Thomas; Gerzanich, Volodymyr

    2009-01-01

    Abstract Frontal impact, closed head trauma is a frequent cause of traumatic brain injury (TBI) in motor vehicle and sports accidents. Diffuse axonal injury (DAI) is common in humans and experimental animals, and results from shearing forces that develop within the anisotropic brain. Because the specific anisotropic properties of the brain are axis-dependent, the anatomical site where force is applied as well as the resultant acceleration, be it linear, rotational, or some combination, are important determinants of the resulting pattern of brain injury. Available rodent models of closed head injury do not reproduce the frontal impact commonly encountered in humans. Here we describe a new rat model of closed head injury that is a modification of the impact-acceleration model of Marmarou. In our model (the Maryland model), the impact force is applied to the anterior part of the cranium and produces TBI by causing anterior-posterior plus sagittal rotational acceleration of the brain inside the intact cranium. Skull fractures, prolonged apnea, and mortality were absent. The animals exhibited petechial hemorrhages, DAI marked by a bead-like pattern of β-amyloid precursor protein (β-APP) in damaged axons, and widespread upregulation of β-APP in neurons, with regions affected including the orbitofrontal cortex (coup), corpus callosum, caudate, putamen, thalamus, cerebellum, and brainstem. Activated caspase-3 was prominent in hippocampal neurons and Purkinje cells at the grey-white matter junction of the cerebellum. Neurobehavioral dysfunction, manifesting as reduced spontaneous exploration, lasted more than 1 week. We conclude that the Maryland model produces diffuse injuries that may be relevant to human brain injury. PMID:19929375

  20. Stress models of depression: forming genetically vulnerable strains.

    PubMed

    Henn, Fritz A; Vollmayr, Barbara

    2005-01-01

    Among the most useful models for depressive disorders are those, which involve a stress induced change in behaviour. Learned helplessness is one such model and is induced through exposure to uncontrollable and unpredictable aversive events. Learned helplessness as induced in rats using foot shock is well characterized and has good face validity and predictive validity as a model of depression, including alterations in HPA axis activity and REM sleep characteristic of depression. The data concerning the validity will be briefly reviewed. The model can also be used to look at the role of genetics through selective breeding. These studies will be reviewed and the utility of the genetic strains for understanding the interaction of stress and affect will be examined. A second model of depression using exposure to chronic stress also has high face and predictive validity. A new form of this approach, recently described, also is suitable for the examination of genetic factors leading to depressive like behaviour and this will be presented. PMID:15925700

  1. Evaluating Nextgen Closely Spaced Parallel Operations Concepts with Validated Human Performance Models: Flight Deck Guidelines

    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.

  2. Scenario-based, closed-loop model predictive control with application to emergency vehicle scheduling

    NASA Astrophysics Data System (ADS)

    Goodwin, Graham. C.; Medioli, Adrian. M.

    2013-08-01

    Model predictive control has been a major success story in process control. More recently, the methodology has been used in other contexts, including automotive engine control, power electronics and telecommunications. Most applications focus on set-point tracking and use single-sequence optimisation. Here we consider an alternative class of problems motivated by the scheduling of emergency vehicles. Here disturbances are the dominant feature. We develop a novel closed-loop model predictive control strategy aimed at this class of problems. We motivate, and illustrate, the ideas via the problem of fluid deployment of ambulance resources.

  3. Art form as an object of cognitive modeling (towards development of Vygotsky`s semiotic model)

    SciTech Connect

    Dmitriev, V.; Perlovsky, L.I.

    1996-12-31

    We suggest a further development of Vygotsky`s esthetic-semiotic model. First, we discuss Vygotsky`s model originally developed for the analysis of Ivan Bunin`s story {open_quotes}Light Breath{close_quotes}. Vygotsky analyzes formal methods used by Bunin to achieve a specific esthetic effect of {open_quote}lightness{close_quotes} while describing {open_quotes}dirty{close_quotes} events of everyday life. According to Vygotsky, this effect is achieved by ordering of events in a non-linear fashion. Vygotsky creams an airy pattern of smooth lines connecting events of story that he first orders linearly in time. And, he insists that this airy pattern creates an impression of airy lightness. In the language of semiotics, the esthetic effect is created by a specific structural organization of signs. Second, we present our critique of Vygotsky`s model. Although, we do not agree with Vygotsky`s sometimes moralistic judgements, and we consider the dynamics between inner personal values and received moral values to be more complicated than implied in his judgements, our critique in this paper is limited to the structure of his semiotic model. We emphasize that Vygotsky`s model does not explicitly account for a hierarchy of multiple levels of semiotic analysis. His analysis regularly slips from one level to another: (1) a lever of cognitive perception by a regular reader is confused with a level of creative genius of a writer; (2) {open_quotes}open{close_quotes} time of real world is mixed up with {open_quote}closed{close_quote} time of the story; (3) events are not organized by the hierarchy of their importance, nor in real world, nor in the inner model of the personages, nor in the story.

  4. Enabling comparative modeling of closely related genomes: Example genus Brucella

    SciTech Connect

    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.

  5. 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.

  6. 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)

  7. Reconstructing the timescale of a catastrophic fan-forming event on Earth using a Mars model

    NASA Astrophysics Data System (ADS)

    Duller, Robert A.; Warner, Nicholas H.; De Angelis, Silvio; Armitage, John J.; Poyatos-Moré, Miquel

    2015-12-01

    The calculation of formation timescales of alluvial fans and deltas on Mars is important as it has direct implications for understanding the planet's hydrologic history. The robustness of sediment transport models is not in doubt but validation of the broad approach using a terrestrial example of similar scale and likely origin, where hydraulic parameters and timescales are known, is useful. Using a catastrophically formed terrestrial fan, where abundant sedimentological information is available, we find that the modeled hydraulic parameters and formation timescales are in very close agreement with the known values of the event. This supports the general modeling approach as applied to Mars fans but also highlights the added value of detailed sedimentary information when reconstructing hydraulics and timescales on Earth and Mars, which cannot be confidently gleaned from the final snapshot of surface geomorphology alone.

  8. The general (2, 2) gauged sigma model with three-form flux

    NASA Astrophysics Data System (ADS)

    Kapustin, Anton; Tomasiello, Alessandro

    2007-11-01

    We find the conditions under which a Riemannian manifold equipped with a closed three-form and a vector field define an on-shell Script N = (2, 2) supersymmetric gauged sigma model. The conditions are that the manifold admits a twisted generalized Kähler structure, that the vector field preserves this structure, and that a so-called generalized moment map exists for it. By a theorem in generalized complex geometry, these conditions imply that the quotient is again a twisted generalized Kähler manifold; this is in perfect agreement with expectations from the renormalization group flow. This method can produce new Script N = (2, 2) models with NS flux, extending the usual Kähler quotient construction based on Kähler gauged sigma models.

  9. Closing the carbon cycle in the EC EARTH earth system model

    NASA Astrophysics Data System (ADS)

    Gröger, Matthias; Döscher, Ralf; Meier, Markus; Svensson, Gunilla

    2015-04-01

    A closed carbon cycle, i.e. the exchange of carbon fluxes between the terrestrial and marine carbon reservoirs (living biomass, soil carbon, sediments etc) via the atmosphere is essential for state of the art earth system models and it will become more and more important in the framework of the Coupled Model Intercomparison Project (CMIP). It is also a prerequisite for simulating the atmospheric pCO2 in a fully prognostic mode and thus, for the realistic simulation of the important feedback of the carbon cycle to the predicted future climate change. The main challenges of this work are two fold: It requires close cooperation between physical oceanographers, meteorologists and biogeochemists. Moreover, especially the marine carbon cycle has very long internal time scales which demand for long spinup phases. The work presented here is the result of the joined efforts of the Meteorological Institute University of Stockholm, the Rossby Center for Climatic Research and the oceanographic department of the Swedish Meteorological and Hydrological Institute (SMHI), and the University of Lund. We here introduce our basic strategy for the implementation of the marine biogeochemistry model PISCES into EC Earth and first results for the marine carbon cycle model PISCES are presented.

  10. Beyond Main Effects Models of Adolescent Work Intensity, Family Closeness, and School Disengagement: Mediational and Conditional Hypotheses.

    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…

  11. Closed-form exact solution to H(infinity) optimization of dynamic vibration absorbers: II. Application to different performance indexes for vibration isolation

    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.

  12. Did the Mississippian Lodgepole buildup at Dickinson Field (North Dakota) form as a gas seep ({open_quotes}vent{close_quotes}) community?

    SciTech Connect

    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.

  13. Form factor expansions in the 2D Ising model and Painlevé VI

    NASA Astrophysics Data System (ADS)

    Mangazeev, Vladimir V.; Guttmann, Anthony J.

    2010-10-01

    We derive a Toda-type recurrence relation, in both high- and low-temperature regimes, for the λ-extended diagonal correlation functions C(N,N;λ) of the two-dimensional Ising model, using an earlier connection between diagonal form factor expansions and tau-functions within Painlevé VI (PVI) theory, originally discovered by Jimbo and Miwa. This greatly simplifies the calculation of the diagonal correlation functions, particularly their λ-extended counterparts. We also conjecture a closed form expression for the simplest off-diagonal case C(0,1;λ) where a connection to PVI theory is not known. Combined with the results for diagonal correlations these give all the initial conditions required for the λ-extended version of quadratic difference equations for the correlation functions discovered by McCoy, Perk and Wu. The results obtained here should provide a further potential algorithmic improvement in the λ-extended case, and facilitate other developments.

  14. Evolution of collective motion in a model glass-forming liquid during physical aging

    NASA Astrophysics Data System (ADS)

    Shavit, Amit; Douglas, Jack F.; Riggleman, Robert A.

    2013-03-01

    At temperatures moderately below their glass transition temperature, the properties of many glass-forming materials can evolve slowly with time in a process known as physical aging whereby the thermodynamic, mechanical, and dynamic properties all drift towards their equilibrium values. In this work, we study the evolution of the thermodynamic and dynamic properties during physical aging for a model polymer glass. Specifically, we test the relationship between an estimate of the size of the cooperative rearrangements taking the form of strings and the effective structural relaxation time predicted by the Adam-Gibbs relationship for both an equilibrium supercooled liquid and the same fluid undergoing physical aging towards equilibrium after a series of temperature jumps. We find that there is apparently a close correlation between a structural feature of the fluid, the size of the string-like rearrangements, and the structural relaxation time, although the relationship for the aging fluid appears to be distinct from that of the fluid at equilibrium.

  15. Numerical modeling of cold room's hinged door opening and closing processes

    NASA Astrophysics Data System (ADS)

    Carneiro, R.; Gaspar, P. D.; Silva, P. D.; Domingues, L. C.

    2016-06-01

    The need of rationalize energy consumption in agrifood industry has fasten the development of methodologies to improve the thermal and energy performances of cold rooms. This paper presents a three-dimensional (3D) transient Computational Fluid Dynamics (CFD) modelling of a cold room to evaluate the air infiltration rate through hinged doors. A species transport model is used for modelling the tracer gas concentration decay technique. Numerical predictions indicate that air temperature difference between spaces affects the air infiltration. For this case study, the infiltration rate increases 0.016 m3 s-1 per K of air temperature difference. The knowledge about the evolution of air infiltration during door opening/closing times allows to draw some conclusions about its influence on the air conditions inside the cold room, as well as to suggest best practices and simple technical improvements that can minimize air infiltration, and consequently improve thermal performance and energy consumption rationalization.

  16. UKF-based closed loop iterative learning control of epileptiform wave in a neural mass model.

    PubMed

    Shan, Bonan; Wang, Jiang; Deng, Bin; Wei, Xile; Yu, Haitao; Li, Huiyan

    2015-02-01

    A novel closed loop control framework is proposed to inhibit epileptiform wave in a neural mass model by external electric field, where the unscented Kalman filter method is used to reconstruct dynamics and estimate unmeasurable parameters of the model. Specifically speaking, the iterative learning control algorithm is introduced into the framework to optimize the control signal. In the proposed method, the control effect can be significantly improved based on the observation of the past attempts. Accordingly, the proposed method can effectively suppress the epileptiform wave as well as showing robustness to noises and uncertainties. Lastly, the simulation is carried out to illustrate the feasibility of the proposed method. Besides, this work shows potential value to design model-based feedback controllers for epilepsy treatment. PMID:26052360

  17. Forming chondrules in impact splashes. I. Radiative cooling model

    SciTech Connect

    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.

  18. Paleodynamics of large closed lakes as a standard for climate modeling data verification

    NASA Astrophysics Data System (ADS)

    Kislov, Alexander

    2015-04-01

    Observed and reconstructed variations of large lakes can serve as a standard for assessing the quality of the model run off simulated by climate models. It provides the opportunity to assess whether models designed for future scenarios are skillful in 'out-of sample' climate change experiments. Based on general ideas about the laws of temporal dynamics relating to massive inertial objects, slow changes of the lake level under the semi-steady climate state can be represented as resulting from the accumulation of small anomalies in the water regime; it appears like a kind of "self-developing" system. To test this hypothesis, the water balance model of the Caspian Sea (CS) was used. Time scale for the CS is estimated as ~20 years. Model is interpreted as stochastic, and from this perspective, it is a Langevin equation that incorporates the action of precipitation and evaporation like random white noise, so that the whole can be thought of as an analogue of Brownian motion. Under these conditions, the CS palaeostages during the Holocene is represented by a system undergoing random walk. It should be emphasized that modeling results are interpreted from the probabilistic point of view, despite the fact that the model is deterministically based on the physical law of conservation of water mass. Despite the CS, another candidate to be as a potential evaluation tool for climate model simulations is the Black Sea (BS) until its merger with the Mediterranean. Therefore, although the image of the CS, BS and other lakes within the climate models is very simplified (or absent), changes in the levels could be used to assess the ability of climate models to reproduce the water budget over the catchment areas. For the CS or the BS, they are the large parts of the East European Plane and can be as indicators of climate model quality. However, the use of reconstructed data of other closed lakes is problematic. It is due to its water budget components cannot be simulated with needed

  19. Closing the Loop for Memory Prostheses: Detecting the Role of Hippocampal Neural Ensembles Using Nonlinear Models

    PubMed Central

    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

  20. Virtual Habitat -a dynamic simulation of closed life support systems -human model status

    NASA Astrophysics Data System (ADS)

    Markus Czupalla, M. Sc.; Zhukov, Anton; Hwang, Su-Au; Schnaitmann, Jonas

    In order to optimize Life Support Systems on a system level, stability questions must be in-vestigated. To do so the exploration group of the Technical University of Munich (TUM) is developing the "Virtual Habitat" (V-HAB) dynamic LSS simulation software. V-HAB shall provide the possibility to conduct dynamic simulations of entire mission scenarios for any given LSS configuration. The Virtual Habitat simulation tool consists of four main modules: • Closed Environment Module (CEM) -monitoring of compounds in a closed environment • Crew Module (CM) -dynamic human simulation • P/C Systems Module (PCSM) -dynamic P/C subsystems • Plant Module (PM) -dynamic plant simulation The core module of the simulation is the dynamic and environment sensitive human module. Introduced in its basic version in 2008, the human module has been significantly updated since, increasing its capabilities and maturity significantly. In this paper three newly added human model subsystems (thermal regulation, digestion and schedule controller) are introduced touching also on the human stress subsystem which is cur-rently under development. Upon the introduction of these new subsystems, the integration of these into the overall V-HAB human model is discussed, highlighting the impact on the most important I/F. The overall human model capabilities shall further be summarized and presented based on meaningful test cases. In addition to the presentation of the results, the correlation strategy for the Virtual Habitat human model shall be introduced assessing the models current confidence level and giving an outlook on the future correlation strategy. Last but not least, the remaining V-HAB mod-ules shall be introduced shortly showing how the human model is integrated into the overall simulation.

  1. Kinematic Modeling of Separation Compression for Paired Approaches to Closely-Spaced Parallel Runways

    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.

  2. Model-Based, Closed-Loop Control of PZT Creep for Cavity Ring-Down Spectroscopy

    PubMed Central

    McCartt, A D; Ognibene, T J; Bench, G; Turteltaub, K W

    2014-01-01

    Cavity ring-down spectrometers typically employ a PZT stack to modulate the cavity transmission spectrum. While PZTs ease instrument complexity and aid measurement sensitivity, PZT hysteresis hinders the implementation of cavity-length-stabilized, data-acquisition routines. Once the cavity length is stabilized, the cavity’s free spectral range imparts extreme linearity and precision to the measured spectrum’s wavelength axis. Methods such as frequency-stabilized cavity ring-down spectroscopy have successfully mitigated PZT hysteresis, but their complexity limits commercial applications. Described herein is a single-laser, model-based, closed-loop method for cavity length control. PMID:25395738

  3. Feasibility of Close-Range Photogrammetric Models for Geographic Information System

    SciTech Connect

    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.

  4. Model oxygen ions distributions in the Earth{close_quote}s magnetosphere for different pitch-angles

    SciTech Connect

    Beliaev, A.A.; Koroteyeva, E.G.; Panasyuk, M.I.

    1996-07-01

    Results of calculations of energetic, spatial and charge distributions of oxygen ions in the Earth{close_quote}s radiation belts are present. The model of oxygen radiation belts for various pitch angles is suggested. Model is based on the solution of stationary Fokker-Planck equation for particles{close_quote} diffusion due to magnetic and electric field fluctuations and accounts for particles losses due to Coulomb interactions and charge exchange. Particles{close_quote} distributions are studied as function of fluctuations{close_quote} power indices and source spectra (both solar and ionospheric) on the magnetosphere boundary. Comparison is made with experimental data. {copyright} {ital 1996 American Institute of Physics.}

  5. 17 CFR 248.2 - Model privacy form: rule of construction.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 17 Commodity and Securities Exchanges 4 2014-04-01 2014-04-01 false Model privacy form: rule of... Safeguarding Personal Information § 248.2 Model privacy form: rule of construction. (a) Model privacy form. Use of the model privacy form in appendix A to subpart A of this part, consistent with the...

  6. 17 CFR 248.2 - Model privacy form: rule of construction.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 17 Commodity and Securities Exchanges 3 2011-04-01 2011-04-01 false Model privacy form: rule of... Safeguarding Personal Information § 248.2 Model privacy form: rule of construction. (a) Model privacy form. Use of the model privacy form in appendix A to subpart A of this part, consistent with the...

  7. 17 CFR 248.2 - Model privacy form: rule of construction.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Model privacy form: rule of... Safeguarding Personal Information § 248.2 Model privacy form: rule of construction. (a) Model privacy form. Use of the model privacy form in Appendix A to Subpart A of this part, consistent with the...

  8. 17 CFR 248.2 - Model privacy form: rule of construction.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 17 Commodity and Securities Exchanges 3 2013-04-01 2013-04-01 false Model privacy form: rule of... Safeguarding Personal Information § 248.2 Model privacy form: rule of construction. (a) Model privacy form. Use of the model privacy form in appendix A to subpart A of this part, consistent with the...

  9. 12 CFR Appendix C to Part 334 - Model Forms for Opt-Out Notices

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the substance, clarity, or meaningful sequence of the language in the model forms. Persons making such... Notice (Single-Affiliate Notice) C-2Model Form for Initial Opt-out Notice (Joint Notice) C-3Model Form for Renewal Notice (Single-Affiliate Notice) C-4Model Form for Renewal Notice (Joint Notice)...

  10. 12 CFR Appendix C to Part 41 - Model Forms for Opt-Out Notices

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., or meaningful sequence of the language in the model forms. Persons making such extensive revisions... comply with § 41.23(a)(2) of this part. C-1 Model Form for Initial Opt-out Notice (Single-Affiliate... (Single-Affiliate Notice) C-4 Model Form for Renewal Notice (Joint Notice) C-5—Model Form for...

  11. Comparative modeling of the latent form of a plant catechol oxidase using a molluskan hemocyanin structure.

    PubMed

    Gerdemann, Carsten; Eicken, Christoph; Galla, Hans Joachim; Krebs, Bernt

    2002-04-10

    The structure of the precursor form of catechol oxidase from sweet potatoes (Ipomoea batatas) has been modeled on the basis of the 3D structural data of mature catechol oxidase [Nat. Struct. Biol. 5 (1998) 1084] and of hemocyanin from giant octopus (Octopus dofleini) [J. Mol. Biol. 278 (1998) 855]. A C-terminal extension peptide is found in the cDNA sequence but not in the purified, mature form of catechol oxidase. Superimposition of the 3D structures of the native hemocyanin and catechol oxidase reveals a close relationship except for an additional C-terminal domain only found in the hemocyanin structure. As sequence alignment shows good homology this domain of the hemocyanin structure was used as a template to model the 3D structure of the C-terminal extension peptide of catechol oxidase. As hemocyanins show no or only weak catecholase activity due to this domain this indicates an inhibitory function of this extension peptide. Beside this possible shielding function for the precursor form, evidence for a function in copper-uptake also increases due to the location of three histidine residues in the model. PMID:11931976

  12. Mathematical modeling of drug release from lipid dosage forms.

    PubMed

    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. PMID:21802501

  13. 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.

  14. A constitutive model for the compressive response of metallic closed-cell foams including micro-inertia effects

    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.

  15. Strongly Correlated Superconductivity close to a Mott transition in orbitally degenerate models

    NASA Astrophysics Data System (ADS)

    Capone, Massimo; Fabrizio, Michele; Castellani, Claudio; Tosatti, Erio

    2004-03-01

    Recently a novel strongly correlated superconductivity (SCS) scenario has been proposed [1] which deals with the question whether and under which conditions Cooper-pairing may get enhanced by strong electron repulsion close to a Mott transition. The core of the SCS proposal is that the effective repulsion between quasiparticles vanishes close to the Mott transition, whereas any pairing attraction will remain unrenormalized if it acts inside the spin channel. This scenario was originally demonstrated through a Dynamical Mean Field Theory (DMFT) solution of a model for doped fullerenes, but it is believed to be far more general. Very recently, a twofold orbitally degenerate model with inverted Hund rule exchange has been proposed as a new candidate for SCS [2]. We report fresh DMFT work that fully confirms this expectation, and provides an extremely appealing phase diagram, where superconductivity arises by doping the Mott insulator, out of an unstable a pseudogapped metal, very much as it happens in cuprates. [1] M. Capone, M. Fabrizio, C. Castellani, and E. Tosatti, Science 296, 2364 (2002). [2] M. Fabrizio, A.F. Ho, L. De Leo, and G. Santoro, Phys. Rev. Lett., to appear; L. De Leo and M. Fabrizio, unpublished.

  16. Closed-Loop Supply Chain Models with Considering the Environmental Impact

    PubMed Central

    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. PMID:25309960

  17. Closed-loop supply chain models with considering the environmental impact.

    PubMed

    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. PMID:25309960

  18. Mathematical modelling of thermoregulation processes for premature infants in closed convectively heated incubators.

    PubMed

    Fraguela, Andrés; Matlalcuatzi, Francisca D; Ramos, Ángel M

    2015-02-01

    The low-weight newborns and especially the premature infants have difficulty in maintaining their temperature in the range considered to be normal. Several studies revealed the importance of thermal environment and moisture to increase the survival rate of newborns. This work models the process of heat exchange and energy balance in premature newborns during the first hours of life in a closed incubator. In addition, a control problem was proposed and solved in order to maintain thermal stability of premature newborns to increase their rate of survival and weight. For this purpose, we propose an algorithm to control the temperature inside the incubator. It takes into account the measurements of the body temperature of a premature newborn which are recorded continuously. We show that using this model the temperature of a premature newborn inside the incubator can be kept in a thermal stability range. PMID:25557201

  19. 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.

  20. Impact of proliferation strategies on food web viability in a model with closed nutrient cycle

    NASA Astrophysics Data System (ADS)

    Szwabiński, Janusz

    2012-11-01

    A food web model with a closed nutrient cycle is presented and analyzed via Monte Carlo simulations. The model consists of three trophic levels, each of which is populated by animals of one distinct species. While the species at the intermediate level feeds on the basal species, and is eaten by the predators living at the highest level, the basal species itself uses the detritus of animals from higher levels as the food resource. The individual organisms remain localized, but the species can invade new lattice areas via proliferation. The impact of different proliferation strategies on the viability of the system is investigated. From the phase diagrams generated in the simulations it follows that in general a strategy with the intermediate level species searching for food is the best for the survival of the system. The results indicate that both the intermediate and top level species play a critical role in maintaining the structure of the system.

  1. 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.

  2. 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.

  3. Cross sections for production of closed superstrings at high energy colliders in brane world models

    SciTech Connect

    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}.

  4. 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.

    2016-07-01

    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.

  5. Structural-acoustic optimum design of shell structures in open/closed space based on a free-form optimization method

    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.

  6. Closed-Form and Numerically-Stable Solutions to Problems Related to the Optimal Two-Impulse Transfer Between Specified Terminal States of Keplerian Orbits

    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.

  7. An exact, closed-form expression of the integral chord-length distribution for the calculation of single-event upsets induced by cosmic rays

    NASA Technical Reports Server (NTRS)

    Luke, Keung L.; Buehler, Martin G.

    1988-01-01

    This paper presents a derivation of an exact closed-form expression of the integral chord-length distribution for the calculation of single-event upsets (SEUs) in an electronic memory cell, caused by cosmic rays. Results computed for two rectangular parallelepipeds using this exact expression are compared with those computed with Bradford's (1979) semiexact expression of C(x). It is found that the values of C(x) are identical for x equal or smaller than b but are vastly different for x greater than b. Moreover, while C(x) of Bradford gives reasonably accurate values of SEU rate for certain sets of computational parameters, it gives values more than 10 times larger than the correct values for other sets of parameters.

  8. Kinetics of color development of melanoidins formed from fructose/amino acid model systems.

    PubMed

    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. PMID:23744115

  9. Mixture models for estimating the size of a closed population when capture rates vary among individuals

    USGS Publications Warehouse

    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.

  10. A Rat Model of Ventricular Fibrillation and Resuscitation by Conventional Closed-chest Technique.

    PubMed

    Lamoureux, Lorissa; Radhakrishnan, Jeejabai; Gazmuri, Raúl J

    2015-01-01

    A rat model of electrically-induced ventricular fibrillation followed by cardiac resuscitation using a closed chest technique that incorporates the basic components of cardiopulmonary resuscitation in humans is herein described. The model was developed in 1988 and has been used in approximately 70 peer-reviewed publications examining a myriad of resuscitation aspects including its physiology and pathophysiology, determinants of resuscitability, pharmacologic interventions, and even the effects of cell therapies. The model featured in this presentation includes: (1) vascular catheterization to measure aortic and right atrial pressures, to measure cardiac output by thermodilution, and to electrically induce ventricular fibrillation; and (2) tracheal intubation for positive pressure ventilation with oxygen enriched gas and assessment of the end-tidal CO2. A typical sequence of intervention entails: (1) electrical induction of ventricular fibrillation, (2) chest compression using a mechanical piston device concomitantly with positive pressure ventilation delivering oxygen-enriched gas, (3) electrical shocks to terminate ventricular fibrillation and reestablish cardiac activity, (4) assessment of post-resuscitation hemodynamic and metabolic function, and (5) assessment of survival and recovery of organ function. A robust inventory of measurements is available that includes - but is not limited to - hemodynamic, metabolic, and tissue measurements. The model has been highly effective in developing new resuscitation concepts and examining novel therapeutic interventions before their testing in larger and translationally more relevant animal models of cardiac arrest and resuscitation. PMID:25938619

  11. Closed-Form Solutions for a Circular Tunnel in Elastic-Brittle-Plastic Ground with the Original and Generalized Hoek-Brown Failure Criteria

    NASA Astrophysics Data System (ADS)

    Chen, Ran; Tonon, Fulvio

    2011-03-01

    The paper presents a closed-form solution for the convergence curve of a circular tunnel in an elasto-brittle-plastic rock mass with both the Hoek-Brown and generalized Hoek-Brown failure criteria, and a linear flow rule, i.e., the ratio between the minor and major plastic strain increments is constant. The improvement over the original solution of Brown et al. (J Geotech Eng ASCE 109(1):15-39, 1983) consists of taking into account the elastic strain variation in the plastic annulus, which was assumed to be fixed in the original solution by Brown et al. The improvement over Carranza-Torres' solution (Int J Rock Mech Min Sci 41(Suppl 1):629-639, 2004) consists of providing a closed-form solution, rather than resorting to numerical integration of an ordinary differential equation. The presented solution, by rigorously following the theory of plasticity, takes into account that the elastic strain components change with radial and circumferential stress changes within the plastic annulus. For the original Hoek-Brown failure criterion, disregarding the elastic strain change leads to underestimate the convergence by up to 55%. For a rock mass failing according to the generalized Hoek-Brown failure criterion, using the original failure criterion leads to a high probability (97%) of underestimating the convergence by up to 100%. As a consequence, the onset or degree of squeezing may be underestimated, and the loading on the support/reinforcement calculated with the convergence/confinement method may be largely underestimated.

  12. Closed-form solution for the Wigner phase-space distribution function for diffuse reflection and small-angle scattering in a random medium.

    PubMed

    Yura, H T; Thrane, L; Andersen, P E

    2000-12-01

    Within the paraxial approximation, a closed-form solution for the Wigner phase-space distribution function is derived for diffuse reflection and small-angle scattering in a random medium. This solution is based on the extended Huygens-Fresnel principle for the optical field, which is widely used in studies of wave propagation through random media. The results are general in that they apply to both an arbitrary small-angle volume scattering function, and arbitrary (real) ABCD optical systems. Furthermore, they are valid in both the single- and multiple-scattering regimes. Some general features of the Wigner phase-space distribution function are discussed, and analytic results are obtained for various types of scattering functions in the asymptotic limit s > 1, where s is the optical depth. In particular, explicit results are presented for optical coherence tomography (OCT) systems. On this basis, a novel way of creating OCT images based on measurements of the momentum width of the Wigner phase-space distribution is suggested, and the advantage over conventional OCT images is discussed. Because all previous published studies regarding the Wigner function are carried out in the transmission geometry, it is important to note that the extended Huygens-Fresnel principle and the ABCD matrix formalism may be used successfully to describe this geometry (within the paraxial approximation). Therefore for completeness we present in an appendix the general closed-form solution for the Wigner phase-space distribution function in ABCD paraxial optical systems for direct propagation through random media, and in a second appendix absorption effects are included. PMID:11140505

  13. β-hairpin-forming peptides; models of early stages of protein folding

    PubMed Central

    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

  14. Synthesis of a control model for a liquid nitrogen cooled, closed circuit, cryogenic nitrogen wind tunnel and its validation

    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.

  15. Form factors in the Bullough-Dodd-related models: The Ising model in a magnetic field

    NASA Astrophysics Data System (ADS)

    Alekseev, O. V.

    2012-11-01

    We consider a certain modification of the free-field representation of the form factors in the Bullough-Dodd model. The two-particle minimal form factors are eliminated from the construction. We consequently obtain a convenient representation for the multiparticle form factors, establish recurrence relations between them, and study their properties. We use the proposed construction to obtain the free-field representation of form factors for the lightest particles in the Φ 1,2 -perturbed minimal models. As an important example, we consider the Ising model in a magnetic field. We verify that the results obtained in the framework of the proposed free-field representation agree with the corresponding results obtained by solving the bootstrap equations.

  16. Form factors in the Bullough-Dodd related models: The Ising model in a magnetic field

    NASA Astrophysics Data System (ADS)

    Alekseev, O. V.

    2012-04-01

    A particular modification of the free-field representation of the form factors in the Bullough-Dodd model is considered. The two-particles minimal form factors are excluded from the construction. As a consequence, a convenient representation for the multiparticle form factors has been obtained, recurrence relations between them have been established, and their properties have been studied. The proposed construction is used to obtain the free-field representation of the lightest particles form factors in the Φ1, 2 perturbed minimal models. The Ising model in a magnetic field is considered as a significant example. The results obtained in the framework of the proposed free-field representation are in agreement with the corresponding results obtained by solving the bootstrap equations.

  17. Integration Of Heat Transfer Coefficient In Glass Forming Modeling With Special Interface Element

    SciTech Connect

    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.

  18. 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.

  19. Dynamic control of modeled tonic-clonic seizure states with closed-loop stimulation.

    PubMed

    Beverlin Ii, Bryce; Netoff, Theoden I

    2012-01-01

    Seizure control using deep brain stimulation (DBS) provides an alternative therapy to patients with intractable and drug resistant epilepsy. This paper presents novel DBS stimulus protocols to disrupt seizures. Two protocols are presented: open-loop stimulation and a closed-loop feedback system utilizing measured firing rates to adjust stimulus frequency. Stimulation suppression is demonstrated in a computational model using 3000 excitatory Morris-Lecar (M-L) model neurons connected with depressing synapses. Cells are connected using second order network topology (SONET) to simulate network topologies measured in cortical networks. The network spontaneously switches from tonic to clonic as synaptic strengths and tonic input to the neurons decreases. To this model we add periodic stimulation pulses to simulate DBS. Periodic forcing can synchronize or desynchronize an oscillating population of neurons, depending on the stimulus frequency and amplitude. Therefore, it is possible to either extend or truncate the tonic or clonic phases of the seizure. Stimuli applied at the firing rate of the neuron generally synchronize the population while stimuli slightly slower than the firing rate prevent synchronization. We present an adaptive stimulation algorithm that measures the firing rate of a neuron and adjusts the stimulus to maintain a relative stimulus frequency to firing frequency and demonstrate it in a computational model of a tonic-clonic seizure. This adaptive algorithm can affect the duration of the tonic phase using much smaller stimulus amplitudes than the open-loop control. PMID:23390413

  20. Dynamic control of modeled tonic-clonic seizure states with closed-loop stimulation

    PubMed Central

    Beverlin II, Bryce; Netoff, Theoden I.

    2013-01-01

    Seizure control using deep brain stimulation (DBS) provides an alternative therapy to patients with intractable and drug resistant epilepsy. This paper presents novel DBS stimulus protocols to disrupt seizures. Two protocols are presented: open-loop stimulation and a closed-loop feedback system utilizing measured firing rates to adjust stimulus frequency. Stimulation suppression is demonstrated in a computational model using 3000 excitatory Morris–Lecar (M–L) model neurons connected with depressing synapses. Cells are connected using second order network topology (SONET) to simulate network topologies measured in cortical networks. The network spontaneously switches from tonic to clonic as synaptic strengths and tonic input to the neurons decreases. To this model we add periodic stimulation pulses to simulate DBS. Periodic forcing can synchronize or desynchronize an oscillating population of neurons, depending on the stimulus frequency and amplitude. Therefore, it is possible to either extend or truncate the tonic or clonic phases of the seizure. Stimuli applied at the firing rate of the neuron generally synchronize the population while stimuli slightly slower than the firing rate prevent synchronization. We present an adaptive stimulation algorithm that measures the firing rate of a neuron and adjusts the stimulus to maintain a relative stimulus frequency to firing frequency and demonstrate it in a computational model of a tonic-clonic seizure. This adaptive algorithm can affect the duration of the tonic phase using much smaller stimulus amplitudes than the open-loop control. PMID:23390413

  1. Algorithms for a Closed-Loop Artificial Pancreas: The Case for Model Predictive Control

    PubMed Central

    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

  2. Nonnegative signal factorization with learnt instrument models for sound source separation in close-microphone recordings

    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.

  3. Hydrodynamics of rotating stars and close binary interactions: Compressible ellipsoid models

    NASA Technical Reports Server (NTRS)

    Lai, Dong; Rasio, Frederic A.; Shapiro, Stuart L.

    1994-01-01

    We develop a new formalism to study the dynamics of fluid polytropes in three dimensions. The stars are modeled as compressible ellipsoids, and the hydrodynamic equations are reduced to a set of ordinary differential equations for the evolution of the principal axes and other global quantities. Both viscous dissipation and the gravitational radiation reaction are incorporated. We establish the validity of our approximations and demonstrate the simplicity and power of the method by rederiving a number of known results concerning the stability and dynamical oscillations of rapidly rotating polytropes. In particular, we present a generalization to compressible fluids of Chandrasekhar's classical results for the secular and dynamical instabilities of incompressible Maclaurin spheroids. We also present several applications of our method to astrophysical problems of great current interest, such as the tidal disruption of a star by a massive black hole, the coalescence of compact binaries driven by the emission of gravitational waves, and the development of instabilities in close binary systems.

  4. Close-range geophotogrammetric mapping of trench walls using multi-model stereo restitution software

    SciTech Connect

    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.

  5. A mechanistic model for the prediction of in-use moisture uptake by packaged dosage forms.

    PubMed

    Remmelgas, Johan; Simonutti, Anne-Laure; Ronkvist, Asa; Gradinarsky, Lubomir; Löfgren, Anders

    2013-01-30

    A mechanistic model for the prediction of in-use moisture uptake of solid dosage forms in bottles is developed. The model considers moisture transport into the bottle and moisture uptake by the dosage form both when the bottle is closed and when it is open. Experiments are carried out by placing tablets and desiccant canisters in bottles and monitoring their moisture content. Each bottle is opened once a day to remove one tablet or desiccant canister. Opening the bottle to remove a tablet or canister also causes some exchange of air between the bottle headspace and the environment. In order to ascertain how this air exchange might depend on the customer, tablets and desiccant canisters are removed from the bottles by either carefully removing only one or by pouring all of the tablets or desiccant canisters out of the bottle, removing one, and pouring the remaining ones back into the bottle. The predictions of the model are found to be in good agreement with experimental data for moisture sorption by desiccant canisters. Moreover, it is found experimentally that the manner in which the tablets or desiccant canisters were removed does not appreciably affect their moisture content. PMID:23194882

  6. Modeling of early stages of island growth during pulsed deposition: Role of closed compact islands

    SciTech Connect

    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.

  7. A model of Stokesian peristalsis and vesicle transport in a three-dimensional closed cavity.

    PubMed

    Aranda, Vivian; Cortez, Ricardo; Fauci, Lisa

    2015-06-25

    The complexity of the mechanics involved in the mammalian reproductive process is evident. Neither an ovum nor an embryo is self-propelled, but move through the oviduct or uterus due to the peristaltic action of the tube walls, imposed pressure gradients, and perhaps ciliary motion. Here we use the method of regularized Stokeslets to model the transport of an ovum or an embryo within a peristaltic tube. We represent the ovum or the embryo as a spherical vesicle of finite volume - not a massless point particle. The outer membrane of the neutrally buoyant vesicle is discretized by nodes that are joined by a network of springs. The elastic moduli of these springs are chosen large enough so that a spherical shape is maintained. For simplicity, here we choose an axisymmetric tube where the geometry of the two-dimensional cross-section along the tube axis reflects that of the sagittal cross-section of the uterine cavity. Although the tube motion is axisymmetric, the presence of the vesicle within the tube requires a fully three-dimensional model. As was found in Yaniv et al. (2009, 2012) for a 2D closed channel, we find that the flow dynamics in a 3D peristaltic tube are strongly influenced by the closed end and the manner in which the peristaltic wave damps out towards the closure. In addition, we demonstrate that the trajectory of a vesicle of finite volume can greatly differ from the trajectory of a massless fluid particle initially placed at the vesicle׳s centroid. PMID:25817334

  8. 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.

  9. Modelling of airflow in a closed simulation box with regard to atmospheric optical link

    NASA Astrophysics Data System (ADS)

    Hajek, Lukas; Latal, Jan; Bojko, Marian; Poboril, Radek; Koudelka, Petr; Vitasek, Jan; Siska, Petr; Vasinek, Vladimir

    2014-03-01

    Article is dealing with defining of mathematical turbulent air flow numerical model in the laboratory box with help of ANSYS Fluent software application. The paper describes real measurement of parameters of mechanical turbulences created by high-speed ventilator mounted on the simulation box. The real measurement took place in two planes perpendicular to each other, input and output slot. Subsequently the simulation of mechanical air flow was performed by the help of k-ɛ and k-ω turbulent models. The results of individual simulations were evaluated by statistical model in the same points, planes respectively, in which the real measurement was made. Other simulation was dealing with effect of heaters inside of closed laboratory box with regards to optical beam degradation. During real measurement was performed temperature point measurement by probe placed inside of the box. The probe was recording air temperature every one second during seven minutes long measurement. The results comparison of simulated and measured data was made in the end. The maximal temperature reached approximately 50 °C in both cases. Also the air flow character in dependence on the number of hot-air extraction ventilators was monitored.

  10. Exact string theory model of closed timelike curves and cosmological singularities

    SciTech Connect

    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.

  11. 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

  12. Comparison of Tests on Air Propellers in Flight with Wind Tunnel Model Tests on Similar Forms

    NASA Technical Reports Server (NTRS)

    Durand, W F; Lesley, E P

    1926-01-01

    The purpose of this investigation was to determine the performance, characteristics, and coefficients of full-sized air propellers in flight and to compare these results with those derived from wind-tunnel tests on reduced scale models of similar geometrical form. The full-scale equipment comprised five propellers in combination with a VE-7 airplane and Wright E-4 engine. This part of the work was carried out at the Langley Memorial Aeronautical Laboratory, between May 1 and August 24, 1924, and was under the immediate charge of Mr. Lesley. The model or wind-tunnel part of the investigation was carried out at the Aerodynamic Laboratory of Stanford University and was under the immediate charge of Doctor Durand. A comparison of the curves for full-scale results with those derived from the model tests shows that while the efficiencies realized in flight are close to those derived from model tests, both thrust developed and power absorbed in flight are from 6 to 10 per cent greater than would be expected from the results of model tests.

  13. 17 CFR Appendix to Subpart B of... - Model Forms

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 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 not... more years, contact us : • By telephone: 1-877-###-#### • On the Web: www.—.com • By mail: check...

  14. Comparative Analysis of Methods to Induce Myocardial Infarction in a Closed-Chest Rabbit Model

    PubMed Central

    Isorni, Marc-Antoine; Casanova, Amaury; Piquet, Julie; Bellamy, Valérie; Pignon, Charly; Puymirat, Etienne; Menasche, Philippe

    2015-01-01

    Objective. To develop a rabbit model of closed-chest catheter-induced myocardial infarction. Background. Limitations of rodent and large animal models justify the search for clinically relevant alternatives. Methods. Microcatheterization of the heart was performed in 47 anesthetized 3-4 kg New Zealand rabbits to test five techniques of myocardial ischemia: free coils (n = 4), interlocking coils (n = 4), thrombogenic gelatin sponge (n = 4), balloon occlusion (n = 4), and alcohol injection (n = 8). In order to limit ventricular fibrillation, an antiarrhythmic protocol was implemented, with beta-blockers/amiodarone before and xylocaine infusion during the procedure. Clinical, angiographic, and echographic data were gathered. End points included demonstration of vessel occlusion (TIMI flow grades 0 and 1 on the angiogram), impairment of left ventricular function at 2 weeks after procedure (by echocardiography), and pathologically confirmed myocardial infarction. Results. The best arterial access was determined to be through the right carotid artery. The internal mammary guiding catheter 4-Fr was selected as the optimal device for selective intracoronary injection. Free coils deployed prematurely and tended to prolapse into the aorta. Interlocking coils did not deploy completely and failed to provide reliable results. Gelatin sponge was difficult to handle, adhered to the catheter, and could not be clearly visualized by fluoroscopy. Balloon occlusion yielded inconsistent results. Alcohol injection was the most efficient and reproducible method for inducing myocardial infarction (4 out of 6 animals), the extent of which could be fine-tuned by using a coaxial balloon catheter as a microcatheter (0.52 mm) to achieve a superselective injection of 0.2 mL of alcohol. This approach resulted in a 20% decrease in LVEF and infarcted myocardium was confirmed histologically. Conclusions. By following a stepwise approach, a minimally invasive, effective, and reproducible

  15. 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).

  16. Model of Close Packing for Determination of the Major Characteristics of the Liquid Dispersions Components

    PubMed Central

    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

  17. Bayesian Analysis of a Reduced-Form Air Quality Model

    EPA Science Inventory

    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...

  18. 12 CFR Appendix C to Part 222 - Model Forms for Opt-Out Notices

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 3 2014-01-01 2014-01-01 false Model Forms for Opt-Out Notices C Appendix C to... SYSTEM (CONTINUED) FAIR CREDIT REPORTING (REGULATION V) Pt. 222, App. C Appendix C to Part 222—Model Forms for Opt-Out Notices a. Although use of the model forms is not required, use of the model forms...

  19. 12 CFR Appendix C to Part 1022 - Model Forms for Opt-Out Notices

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 8 2013-01-01 2013-01-01 false Model Forms for Opt-Out Notices C Appendix C to...) Pt. 1022, App. C Appendix C to Part 1022—Model Forms for Opt-Out Notices a. Although use of the model forms is not required, use of the model forms in this appendix (as applicable) complies with...

  20. 12 CFR Appendix C to Part 334 - Model Forms for Opt-Out Notices

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 5 2012-01-01 2012-01-01 false Model Forms for Opt-Out Notices C Appendix C to... POLICY FAIR CREDIT REPORTING Pt. 334, App. C Appendix C to Part 334—Model Forms for Opt-Out Notices a. Although use of the model forms is not required, use of the model forms in this Appendix (as...