Science.gov

Sample records for avrami equation inadequacy

  1. Evaluation of the recrystallization kinetics of hot-melt extruded polymeric solid dispersions using an improved Avrami equation.

    PubMed

    Feng, Xin; Ye, Xingyou; Park, Jun-Bom; Lu, Wenli; Morott, Joe; Beissner, Brad; Lian, Zhuoyang John; Pinto, Elanor; Bi, Vivian; Porter, Stu; Durig, Tom; Majumdar, Soumyajit; Repka, Michael A

    2015-01-01

    The recrystallization of an amorphous drug in a solid dispersion system could lead to a loss in the drug solubility and bioavailability. The primary objective of the current research was to use an improved kinetic model to evaluate the recrystallization kinetics of amorphous structures and to further understand the factors influencing the physical stability of amorphous solid dispersions. Amorphous solid dispersions of fenofibrate with different molecular weights of hydroxypropylcellulose, HPC (Klucel™ LF, EF, ELF) were prepared utilizing hot-melt extrusion technology. Differential scanning calorimetry was utilized to quantitatively analyze the extent of recrystallization in the samples stored at different temperatures and relative humidity (RH) conditions. The experimental data were fitted into the improved kinetics model of a modified Avrami equation to calculate the recrystallization rate constants. Klucel LF, the largest molecular weight among the HPCs used, demonstrated the greatest inhibition of fenofibrate recrystallization. Additionally, the recrystallization rate (k) decreased with increasing polymer content, however exponentially increased with higher temperature. Also k increased linearly rather than exponentially over the range of RH studied.

  2. Inadequacies of the Rayleigh equations as a model for the fractional crystallization of felsic magma chambers

    SciTech Connect

    Holmes, R.D.

    1985-01-01

    Although it is mostly employed to estimate the amount of crystallization needed to form the observed members of a magmatic suite from a given parental magma, the Rayleigh distillation equation can also be used to quantitatively model igneous variation trends. On a simple x-y variation diagram there are four geometrically possible combinations of slope (+ or -) and curvature (up and down), but differentiation of the Rayleigh equation using the method of parametric equations shows that one of these four patterns is mathematically forbidden. However, this forbidden curvature is, in fact, observed in a number of simple comagmatic suites. This inadequacy in the simple Rayleigh equation was overcome by developing a physical model that takes into account the role of preexisting solid crystals in the magmatic fractionation process. These phenocrysts act as relatively inert particles that are concentrated into the cumulates that accrete at the crystallization interface along the chamber's walls. Moreover, the abundance of phenocrysts in the residual magma is progressively diluted by the remixing of fractionated melts that escape from this zone of dynamic crystallization. Using existing distribution coefficients, this model is able to elegantly explain the occurrence of forbidden curvature. Additionally, the model offers powerful insights into the origin of granitic textures and provides the key to interpreting the bulk line of descent (as distinct from the liquid line of descent).

  3. Inadequacy of the Mott-Schottky equation in strongly pinned double Schottky barriers with no deep donors

    NASA Astrophysics Data System (ADS)

    Schipani, F.; Aldao, C. M.; Ponce, M. A.

    2012-12-01

    The capacitive behaviour of an intergranular double Schottky barrier in a polycrystalline semiconductor was evaluated. We found that the widely applied version of the Mott-Schottky equation can lead to significant errors. Even though we considered strong Fermi level pinning at the interface and no deep levels, the Mott-Schottky equation can be inadequate leading to huge errors due to voltage splitting at double Schottky barriers. Experiments carried out on ZnO varistors corroborated the main trends of our analysis.

  4. On the validity of Avrami formalism in primary crystallization

    NASA Astrophysics Data System (ADS)

    Bruna, Pere; Crespo, Daniel; González-Cinca, Ricard; Pineda, Eloi

    2006-09-01

    Calorimetric data of primary crystallization is usually interpreted in the framework of the Kolmogorov [Dokl. Akad. Nauk SSSR 1, 355 (1937)], Johnson and Mehl [Trans. AIME 135, 416 (1939)], and Avrami [J. Chem. Phys. 7, 1103 (1939); 8, 212 (1940); 9, 177 (1941)] (KJMA) theory. However, while the KJMA theory assumes random nucleation and exhaustion of space by direct impingement, primary crystallization is usually driven by diffusion-controlled growth with soft impingement between the growing crystallites. This results in a stop of the growth before the space is fully crystallized and induces nonrandom nucleation. In this work, phase-field simulations are used to check the validity of different kinetic models for describing primary crystallization kinetics. The results show that KJMA theory provides a good approximation to the soft-impingement and nonrandom nucleation effects. Moreover, these effects are not responsible of the slowing down of the kinetics found experimentally in the primary crystallization of glasses.

  5. Hypnotherapy and Female Sexual Inadequacy

    PubMed Central

    Glick, Daniel

    1972-01-01

    Dr. Glick describes the use of hypnosis in the treatment of primary and secondary frigidity, dyspareunia and psychosomatic symptoms in female sexual inadequacy. He uses case histories to show the various techniques used and the results that can be expected. PMID:20468741

  6. A texture-component Avrami model for predicting recrystallization textures, kinetics and grain size

    NASA Astrophysics Data System (ADS)

    Raabe, Dierk

    2007-03-01

    The study presents an analytical model for predicting crystallographic textures and the final grain size during primary static recrystallization of metals using texture components. The kinetics is formulated as a matrix variant of the Johnson-Mehl-Avrami-Kolmogorov equation. The matrix form is required since the kinetic and crystallographic evolution of the microstructure is described in terms of a limited set of growing (recrystallizing) and swept (deformed) texture components. The number of components required (5-10) defines the order of the matrix since the kinetic coupling occurs between all recrystallizing and all deformed components. Each such couple is characterized by corresponding values for the nucleation energy and grain boundary mobility. The values of these parameters can be obtained by analytical or numerical coarse graining according to a renormalization scheme which replaces many individual grains which grow via recrystallization in a deformed texture component by a single equivalent recrystallization texture component or by fitting to experimental data. Each deformed component is further characterized by an average stored deformation energy. Each element of the kinetic matrix, reflecting one of the possible couplings between a deformed and a recrystallizing texture component, is then derived in each time step by a set of two differential equations. The first equation describes the thermally activated nucleation and growth processes for the expanded (free) volume for a particular couple of a deformed and a recrystallizing texture component and the second equation is used for calculating the constrained (real) volume for that couple which corrects the free volume for those portions of the deformation component which were already swept. The new method is particularly developed for the fast and physically based process simulation of recrystallization textures with respect to processing. The present paper introduces the method and applies it to the

  7. Order and randomness in Kolmogorov-Johnson-Mehl-Avrami-type phase transitions

    NASA Astrophysics Data System (ADS)

    Fanfoni, M.; Persichetti, L.; Tomellini, M.

    2012-09-01

    The distribution of points on a 2D domain influences the kinetics of its coverage when a growth law is attached at each point. This implies that the kinetics of space filling can be adopted as a descriptor of the degree of order of the initial point distribution. In this paper, the degree of order of an initial array of points has been changed following two paths: (i) from a regular square lattice, through increasing displacement assigned to each point, towards Poissonian disorder; (ii) from a Poissonian distribution, by introducing a hard core potential with increasing correlation lengths, towards a more ordered lattice. A linear growth law has been attached to the points of the initial array and the kinetics X(Xe), where Xe is the extended coverage as defined in the Kolmogorov-Johnson-Mehl-Avrami model, has been monitored. The quantitative analysis has been performed by fitting the kinetics to an equation which we propose for the first time and which has proved to be, in fact, highly suitable for the purpose. The results demonstrate that the gross of variation from order to disorder is obtained for point displacements, u, of the order of a, the latter being the constant of a square lattice. Vice versa, the introduction of a correlation distance in a random distribution provokes at most an order limited to the first neighbors and no real order can ever be reached. Others descriptors have been investigated, all confirming our results. We also developed an analytical description based on the use of the f-functions, as have been defined by Van Kampen, up to the second order terms. Such a description has been shown to work well for u/a < 1 within an interval ΔXe which depends on the ɛ value.

  8. Phase transformation kinetics of Voronoi cells in space tessellation governed by the Kolmogorov-Johnson-Mehl-Avrami model

    NASA Astrophysics Data System (ADS)

    Tomellini, Massimo

    2017-03-01

    On the basis of the Kolmogorov-Johnson-Mehl-Avrami (KJMA) method for space tessellation the kinetics of Voronoi cell filling, by central grain growth, has been studied as a function of the cell size. This is done by solving an integral equation for which a class of solutions is obtained in closed form, where the cell-size probability density is the Gamma distribution function. The computation gives the time evolution of the mean grain size, as a function of cell volume, which is further employed for describing the grain-size probability density function. The present approach is applied to determine, analytically, the exact grain-size distribution function in 1D and the size distributions in 2D and 3D through approximation.

  9. Representing Model Inadequacy in Combustion Kinetics

    NASA Astrophysics Data System (ADS)

    Morrison, Rebecca E.; Moser, Robert D.

    2014-11-01

    An accurate description of the chemical processes involved in the oxidation of hydrocarbons may include hundreds of reactions and thirty or more chemical species. Kinetics models of these chemical mechanisms are often embedded in a fluid dynamics solver to represent combustion. Because the computational cost of such detailed mechanisms is so high, it is common practice to use drastically reduced mechanisms. But, this introduces modeling errors which may render the model inadequate. In this talk, we present a formulation of the model inadequacy in reduced models of hydrogen-methane combustion. Our goal is to account for the discrepancy between the high-fidelity model and its reduced version by incorporating an additive, linear, probabilistic inadequacy model. In effect, it is a random matrix, whose entries are characterized by probability distributions and which displays interesting properties due to conservation constraints. The distributions are calibrated via Bayesian inference using a hierarchical modeling scheme and high-dimensional MCMC. We apply this technique to a stand-alone reaction and also incorporate it within a one-dimensional laminar flame problem.

  10. Crystallisation kinetics of some archetypal ionic liquids: isothermal and non-isothermal determination of the Avrami exponent.

    PubMed

    Pas, Steven J; Dargusch, Matthew S; MacFarlane, Douglas R

    2011-07-07

    The properties of ionic liquids give rise to applications in diverse technology areas including mechanical engineering, mining, aerospace and defence. The arbitrary physical property that defines an ionic liquid is a melting point below 100 °C, and as such, an understanding of crystallisation phenomena is extremely important. This is the first report dealing with the mechanism of crystallisation in ionic liquids. Assuming crystallisation of the ionic liquids is a thermal or mass diffusion-controlled process, the values of the isothermal Avrami exponent obtained from three different ionic liquids with three different anions and cations all indicate that growth occurs with a decreasing nucleation rate (n=1.8-2.2). For one of the ionic liquids it was possible to avoid crystallisation by fast cooling and then observe a devitrification upon heating through the glass transition. The isothermal Avrami exponent of devitrification suggested growth with an increasing nucleating rate (n=4.1), compared to a decreasing nucleation rate when crystallisation occurs on cooling from the melt (n=2.0). Two non-isothermal methods were employed to determine the Avrami exponent of devitrification. Both non-isothermal Avrami exponents were in agreement with the isothermal case (n=4.0-4.15). The applicability of JMAK theory suggests that the nucleation event in the ionic liquids selected is a random stochastic process in the volume of the material. Agreement between the isothermal and non-isothermal techniques for determining the Avrami exponent of devitrification suggests that the pre-exponential factor and the activation energy are independent of thermal history. The heating rate dependence of the glass transition enabled the calculation of the fragility index, which suggests that the ionic liquid is a "strong" glass former. This suggests that the temperature dependence of the rate constant could be close to Arrhenius, as assumed by JMAK theory. More generally, therefore, it can be

  11. Vitamin D inadequacy in pregnancy: biology, outcomes, and interventions

    USDA-ARS?s Scientific Manuscript database

    A high prevalence of maternal vitamin D inadequacy during pregnancy and at delivery has been demonstrated in various ethnic populations living at different latitudes. Because placental transfer of 25(OH)D is the major source of vitamin D to the developing human fetus, there is growing concern about ...

  12. Nutrient inadequacy among nutritionally vulnerable populations in the US

    USDA-ARS?s Scientific Manuscript database

    Objective: To estimate the prevalence of inadequacy of selected nutrients among participants in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC); participants in the Supplemental Nutrition Assistance Program (SNAP); and those with low/very low food security status. ...

  13. An Inadequacy Formulation for an Uncertain Flamelet Model

    NASA Astrophysics Data System (ADS)

    Sondak, David; Oliver, Todd; Simmons, Chris; Moser, Robert

    2016-11-01

    We report progress on the development of an uncertain flamelet library for use in non-premixed turbulent combustion. A stochastic inadequacy operator is generalized from previous work and is now used to incorporate uncertainties in chemical reaction mechanisms in a flamelet model. The original form of the inadequacy operator was designed to enforce positivity of chemical species concentrations and conservation of species while representing inadequacies in reduced chemical mechanisms. As a first step towards generalization, we are exploring temperature dependent modifications to the inadequacy operator. The temperature dependence helps ensure that the operator is inactive in the absence of chemical reactions and becomes active only after ignition. A Bayesian inverse problem is used to calibrate the stochastic operator on a hydrogen-oxygen zero-dimensional reactor and to infer model parameters, and their uncertainties, from data obtained via a detailed chemical mechanism. The inferred model parameters are then propagated through a laminar, non-premixed, counterflow hydrogen-oxygen flame. Temperature and species profiles at various scalar dissipation rates are compared to those predicted from a five-reaction reduced model and the detailed model.

  14. Crystal Growth Simulations To Establish Physically Relevant Kinetic Parameters from the Empirical Kolmogorov-Johnson-Mehl-Avrami Model

    SciTech Connect

    Dill, Eric D.; Folmer, Jacob C.W.; Martin, James D.

    2013-12-05

    A series of simulations was performed to enable interpretation of the material and physical significance of the parameters defined in the Kolmogorov, Johnson and Mehl, and Avrami (KJMA) rate expression commonly used to describe phase boundary controlled reactions of condensed matter. The parameters k, n, and t0 are shown to be highly correlated, which if unaccounted for seriously challenge mechanistic interpretation. It is demonstrated that rate measurements exhibit an intrinsic uncertainty without precise knowledge of the location and orientation of nucleation with respect to the free volume into which it grows. More significantly, it is demonstrated that the KJMA rate constant k is highly dependent on sample size. However, under the simulated conditions of slow nucleation relative to crystal growth, sample volume and sample anisotropy correction affords a means to eliminate the experimental condition dependence of the KJMA rate constant, k, producing the material-specific parameter, the velocity of the phase boundary, vpb.

  15. Representing Model Inadequacy in Combustion Mechanisms of Laminar Flames

    NASA Astrophysics Data System (ADS)

    Morrison, Rebecca; Moser, Robert; Oliver, Todd

    2015-11-01

    An accurate description of the chemical processes involved in the oxidation of hydrocarbons may include hundreds of reactions and thirty or more chemical species. Kinetics models of these chemical mechanisms are often embedded in a fluid dynamics solver to represent combustion. Because the computational cost of such detailed mechanisms is so high, it is common practice to use drastically reduced mechanisms. But, this introduces modeling errors which may render the model inadequate. In this talk, we present a formulation of the model inadequacy in reduced models of combustion mechanisms. Our goal is to account for the discrepancy between the detailed model and its reduced version by incorporating an additive, linear, probabilistic inadequacy model. In effect, it is a random matrix, whose entries are characterized by probability distributions and which displays interesting properties due to conservation constraints. In particular, we investigate how the inclusion of the random matrix affects the prediction of flame speed in a one-dimensional hydrogen laminar flame.

  16. Test of the Kolmogorov-Johnson-Mehl-Avrami picture of metastable decay in a model with microscopic dynamics

    NASA Astrophysics Data System (ADS)

    Ramos, Raphael A.; Rikvold, Per Arne; Novotny, M. A.

    1999-04-01

    The Kolmogorov-Johnson-Mehl-Avrami (KJMA) theory for the time evolution of the order parameter in systems undergoing first-order phase transformations has been extended by Sekimoto to the level of two-point correlation functions. Here, this extended KJMA theory is applied to a kinetic Ising lattice-gas model, in which the elementary kinetic processes act on microscopic length and time scales. The theoretical framework is used to analyze data from extensive Monte Carlo simulations. The theory is inherently a mesoscopic continuum picture, and in principle it requires a large separation between the microscopic scales and the mesoscopic scales characteristic of the evolving two-phase structure. Nevertheless, we find excellent quantitative agreement with the simulations in a large parameter regime, extending remarkably far towards strong fields (large supersaturations) and correspondingly small nucleation barriers. The original KJMA theory permits direct measurement of the order parameter in the metastable phase, and using the extension to correlation functions one can also perform separate measurements of the nucleation rate and the average velocity of the convoluted interface between the metastable and stable phase regions. The values obtained for all three quantities are verified by other theoretical and computational methods. As these quantities are often difficult to measure directly during a process of phase transformation, data analysis using the extended KJMA theory may provide a useful experimental alternative.

  17. Model inadequacy and mistaken inferences of trait-dependent speciation.

    PubMed

    Rabosky, Daniel L; Goldberg, Emma E

    2015-03-01

    Species richness varies widely across the tree of life, and there is great interest in identifying ecological, geographic, and other factors that affect rates of species proliferation. Recent methods for explicitly modeling the relationships among character states, speciation rates, and extinction rates on phylogenetic trees- BiSSE, QuaSSE, GeoSSE, and related models-have been widely used to test hypotheses about character state-dependent diversification rates. Here, we document the disconcerting ease with which neutral traits are inferred to have statistically significant associations with speciation rate. We first demonstrate this unfortunate effect for a known model assumption violation: shifts in speciation rate associated with a character not included in the model. We further show that for many empirical phylogenies, characters simulated in the absence of state-dependent diversification exhibit an even higher Type I error rate, indicating that the method is susceptible to additional, unknown model inadequacies. For traits that evolve slowly, the root cause appears to be a statistical framework that does not require replicated shifts in character state and diversification. However, spurious associations between character state and speciation rate arise even for traits that lack phylogenetic signal, suggesting that phylogenetic pseudoreplication alone cannot fully explain the problem. The surprising severity of this phenomenon suggests that many trait-diversification relationships reported in the literature may not be real. More generally, we highlight the need for diagnosing and understanding the consequences of model inadequacy in phylogenetic comparative methods.

  18. 40 CFR 52.32 - Sanctions following findings of SIP inadequacy.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 3 2012-07-01 2012-07-01 false Sanctions following findings of SIP inadequacy. 52.32 Section 52.32 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... following findings of SIP inadequacy. For purposes of the SIP revisions required by § 51.120, EPA may make...

  19. 40 CFR 52.32 - Sanctions following findings of SIP inadequacy.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Sanctions following findings of SIP inadequacy. 52.32 Section 52.32 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... following findings of SIP inadequacy. For purposes of the SIP revisions required by § 51.120, EPA may make...

  20. 40 CFR 52.32 - Sanctions following findings of SIP inadequacy.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Sanctions following findings of SIP inadequacy. 52.32 Section 52.32 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... following findings of SIP inadequacy. For purposes of the SIP revisions required by § 51.120, EPA may make...

  1. 40 CFR 52.32 - Sanctions following findings of SIP inadequacy.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Sanctions following findings of SIP inadequacy. 52.32 Section 52.32 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... following findings of SIP inadequacy. For purposes of the SIP revisions required by § 51.120, EPA may make...

  2. 40 CFR 52.32 - Sanctions following findings of SIP inadequacy.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Sanctions following findings of SIP inadequacy. 52.32 Section 52.32 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... following findings of SIP inadequacy. For purposes of the SIP revisions required by § 51.120, EPA may make...

  3. Vitamin E Inadequacy in Humans: Causes and Consequences12

    PubMed Central

    Traber, Maret G.

    2014-01-01

    It is estimated that >90% of Americans do not consume sufficient dietary vitamin E, as α-tocopherol, to meet estimated average requirements. What are the adverse consequences of inadequate dietary α-tocopherol intakes? This review discusses health aspects where inadequate vitamin E status is detrimental and additional vitamin E has reversed the symptoms. In general, plasma α-tocopherol concentrations <12 μmol/L are associated with increased infection, anemia, stunting of growth, and poor outcomes during pregnancy for both the infant and the mother. When low dietary amounts of α-tocopherol are consumed, tissue α-tocopherol needs exceed amounts available, leading to increased damage to target tissues. Seemingly, adequacy of human vitamin E status cannot be assessed from circulating α-tocopherol concentrations, but inadequacy can be determined from “low” values. Circulating α-tocopherol concentrations are very difficult to interpret because, as a person ages, plasma lipid concentrations also increase and these elevations in lipids increase the plasma carriers for α-tocopherol, leading to higher circulating α-tocopherol concentrations. However, abnormal lipoprotein metabolism does not necessarily increase α-tocopherol delivery to tissues. Additional biomarkers of inadequate vitamin E status are needed. Urinary excretion of the vitamin E metabolite α-carboxy-ethyl-hydroxychromanol may fulfill this biomarker role, but it has not been widely studied with regard to vitamin E status in humans or with regard to health benefits. This review evaluated the information available on the adverse consequences of inadequate α-tocopherol status and provides suggestions for avenues for research. PMID:25469382

  4. Inadequacy of in-school support for diabetic children.

    PubMed

    Lewis, Dalila W; Powers, Patricia A; Goodenough, Mary F; Poth, Merrily A

    2003-01-01

    The level of blood glucose control needed to minimize complications in children with diabetes requires frequent blood sugar monitoring and appropriate responses to the information obtained. It is our impression that optimal support for good control is not available in all of the schools our patients attend. The objective of this study was to identify and quantify barriers to good control of diabetes in the school setting, and then use this information to target interventions to improve in-school support for children with diabetes. Two questionnaires were designed based on recommendations of the American Diabetes Association for appropriate in-school support for children with diabetes. Parental perception of in-school resources was addressed in one questionnaire. Forty-seven parents of children with diabetes in our clinic were surveyed. The second questionnaire was mailed to 222 randomly selected schools in our area inquiring about the in-school support available to children with diabetes and the types of educational materials that would be useful for school personnel. Thirty percent of the parents of children with diabetes indicated that the in-school support of their child was insufficient. Sixty-five of the 222 schools surveyed responded. The responses were variable and demonstrated inconsistency and, in some cases, inadequacy of support. A major deficiency noted in 13% of schools was lack of on-site personnel trained in diabetes management skills. From the schools' perspective, however, 50% of schools reported lack of parental communication. The care available for the child with diabetes is highly variable among schools. Targeted educational materials for both school personnel and parents would be useful to improve support for these children.

  5. High Educational Aspirations Among Pregnant Adolescents Are Related to Pregnancy Unwantedness and Subsequent Parenting Stress and Inadequacy

    PubMed Central

    East, Patricia L.; Barber, Jennifer S.

    2015-01-01

    On the basis of theories of maternal identity development, role conflict, and childbearing motivation, the authors tested whether high educational aspirations among pregnant adolescents are related to the unwantedness of the pregnancy and whether pregnancy unwantedness leads to subsequent parenting stress and inadequacy. Longitudinal data from 100 first-time-pregnant, unmarried Latina adolescents (M age = 17.3 years) were analyzed. Results from structural equation path modeling confirmed these associations, with strong educational ambitions related to greater unwantedness of the pregnancy, which led to feeling trapped by parenting at 6 months postpartum, which in turn was related to unaffectionate parenting and feeling inadequate in mothering at 1 year postpartum. The potential long-term negative consequences of high educational aspirations for pregnant adolescents’ adjustment to parenting are discussed. PMID:25641985

  6. Inadequacy of single-impulse transfers for path constrained rendezvous

    NASA Technical Reports Server (NTRS)

    Stern, S. A.; Soileau, K. M.

    1987-01-01

    The use of single-impulse techniques to maneuver from point to point about a large space structure (LSS) with an arbitrary geometrical configuration and spin is examined. Particular consideration is given to transfers with both endpoints on the forbidden zone surface. Clohessy-Wiltshire equations of relative motion are employed to solve path constrained rendezvous problems. External and internal transfers between arbitrary points are analyzed in terms of tangential departure and arrival conditions. It is observed that single-impulse techniques are inadequate for transferring about the exterior of any LSS; however, single-impulse transfers are applicable for transfers in the interior of LSSs. It is concluded that single-impulse transducers are not applicable for path constrained rendezvous guidance.

  7. Effects of antibiotic administration delay and inadequacy upon the survival of septic shock patients.

    PubMed

    Suberviola Cañas, B; Jáuregui, R; Ballesteros, M Á; Leizaola, O; González-Castro, A; Castellanos-Ortega, Á

    2015-11-01

    To assess how antibiotic administration delay and inadequacy influence survival in septic shock patients. A prospective, observational cohort study was carried out between September 2005 and September 2010. Patients admitted to the ICU of a third level hospital. A total of 342 septic shock patients None The time to antibiotic administration (difference between septic shock presentation and first administered dose of antibiotic) and its adequacy (in vitro susceptibility testing of isolated pathogens) were determined. ICU and hospital mortality were 26.4% and 33.5%, respectively. The median delay to administration of the first antibiotic dose was 1.7h. Deceased patients received antibiotics significantly later than survivors (1.3±14.5h vs. 5.8±18.02h; P=.001). Percentage drug inadequacy was 12%. Those patients who received inadequate antibiotics had significantly higher mortality rates (33.8% vs. 51.2%; P=.03). The coexistence of treatment delay and inadequacy was associated to lower survival rates. Both antibiotic administration delay and inadequacy exert deleterious effects upon the survival of septic shock patients, independently of their characteristics or severity. Copyright © 2015 Elsevier España, S.L.U. and SEMICYUC. All rights reserved.

  8. The Inadequacy of Academic Environment Contributes to Inadequate Teaching and Learning Phenomena

    ERIC Educational Resources Information Center

    Quasim, Shahla; Arif, Muhammad Shahbaz

    2014-01-01

    This study aims at the inadequacy of academic environment as an indicator contributing to the inadequate teaching and learning situation in Pakistan. The main focus is to look into the low proficiency of students in the subject of English at secondary school level. A comprehensive questionnaire was designed from the literature concerned and The…

  9. Anemia in postmenopausal women: dietary inadequacy or non-dietary factors

    USDA-ARS?s Scientific Manuscript database

    Postmenopausal women are disproportionately affected by anemia, and the prevalence in females > 65 years of age in the United States is approximately 10%. The manifestation of anemia in older populations is associated with dietary inadequacy, blood loss, genetics, alterations in bioavailability, ren...

  10. The Inadequacy of Academic Environment Contributes to Inadequate Teaching and Learning Phenomena

    ERIC Educational Resources Information Center

    Quasim, Shahla; Arif, Muhammad Shahbaz

    2014-01-01

    This study aims at the inadequacy of academic environment as an indicator contributing to the inadequate teaching and learning situation in Pakistan. The main focus is to look into the low proficiency of students in the subject of English at secondary school level. A comprehensive questionnaire was designed from the literature concerned and The…

  11. Development of Continuous Cooling Transformation Diagrams of Zirconium-Niobium Alloy Phase Transformations within the Kolmogorov-Johnson-Mehl-Avrami Framework

    NASA Astrophysics Data System (ADS)

    Kautz, Elizabeth J.

    Microstructure and chemistry of zirconium alloys have a major influence on material performance, including mechanical properties and corrosion resistance. Therefore, it is essential to thoroughly understand processing required to obtain desired microstructures for application in commercial nuclear reactors. Zirconium-niobium alloys are of particular interest for commercial nuclear applications (e.g., in boiling water reactors, pressurized water reactors, Canadian deuterium uranium reactors) due to increased corrosion resistance in aqueous environments over other zirconium alloys. Heat treatments of zirconium-niobium alloys affect overall microstructure, precipitate distributions and size, and ultimately determine material performance. Phase transformations in zirconium-niobium alloys were modeled for a range of niobium concentrations and heat treatment conditions, by conducting controlled experiments. Heat-flux differential scanning calorimetry was performed and data was collected and analyzed for zirconium-niobium alloys with niobium content ranging from 0.6-3.0 weight percent. Continuous cooling transformation diagrams were constructed for slow cooling rate conditions (9-34°C/minute) based on calorimetry test results. A standard operating procedure for performing these calorimetry tests and corresponding data analysis technique was developed specifically to study the zirconium-niobium material system. A mathematical model was developed utilizing the Kolmogorov-Johnson-Mehl-Avrami theory that accurately describes phase transformations upon continuous cooling in zirconium-niobium binary alloys. This model relates fraction of phase transformed to kinetic parameters that were calculated from experimental test results in order to model the phase transformation for various cooling rates from 10-40°C/minute.

  12. Are Dieting and Dietary Inadequacy a Second Hit in the Association with Polycystic Ovary Syndrome Severity?

    PubMed Central

    Huijgen, Nicole A.; Laven, Joop S. E.; Labee, Chantal T.; Louwers, Yvonne V.; Willemsen, Sten P.; Steegers-Theunissen, Régine P. M.

    2015-01-01

    Background The composition of the diet is of increasing importance for the development and maturation of the ovarian follicles. In Polycystic Ovary Syndrome (PCOS) healthy dietary interventions improve the clinical spectrum. We hypothesized that dieting and diet inadequacy in the reproductive life course is associated with impaired programming of ovarian follicles and contributes to the severity of the PCOS phenotype. Methods and Findings To determine associations between the use of a self-initiated diet and diet inadequacy and the severity of the PCOS phenotype, we performed an explorative nested case control study embedded in a periconception cohort of 1,251 patients visiting the preconception outpatient clinic. 218 patients with PCOS and 799 subfertile controls were selected from the cohort and self-administered questionnaires, anthropometric measurements and blood samples were obtained. The Preconception Dietary Risk Score (PDR score), based on the Dutch dietary guidelines, was used to determine diet inadequacy in all women. The PDR score was negatively associated to cobalamin, serum and red blood cell folate and positively to tHcy. PCOS patients (19.9%), in particular the hyperandrogenic (HA) phenotype (22.5%) reported more often the use of a self-initiated diet than controls (13.1%; p = 0.023). The use of an inadequate diet was also significantly higher in PCOS than in controls (PDR score 3.7 vs 3.5; p = 0.017) and every point increase was associated with a more than 1.3 fold higher risk of the HA phenotype (adjusted OR 1.351, 95% CI 1.09–1.68). Diet inadequacy was independently associated with the anti-Müllerian Hormone (AMH) concentration (β 0.084; p = 0.044; 95% CI 0.002 to 0.165) and free androgen index (β 0.128; p = 0.013; 95% CI 0.028 to 0.229) in PCOS patients. Conclusions The use of a self-initiated diet and diet inadequacy is associated with PCOS, in particular with the severe HA phenotype. This novel finding substantiated by the association

  13. Thiamin inadequacy in infants: lack of evidence of amprolium in egg yolk.

    PubMed

    Thornber, E J; Elliott, L E; Kerr, D; Marriott, J M; Massera, F C

    1983-02-01

    This study investigated the hypothesis that the consumption of egg yolks might lead to thiamin inadequacy in infants because of the possible contamination of the egg yolks with amprolium. Earlier workers showed that the presence of amprolium in the diet inhibits the absorption of thiamin. Amprolium is added to some poultry feeds to control coccidiosis: it is readily incorporated in the egg yolk and egg yolk is one of the solid foods offered to infants at weaning. We found that under current commercial poultry feeding practices in WA it is extremely unlikely that any amprolium would be present in commercial eggs or poultry. Amprolium was undetectable in eggs purchased at several retail outlets. Thus there is no evidence that consumption of egg yolk contributes to thiamin inadequacy in infants.

  14. Prevalence and predictors of vitamin D inadequacy amongst Lebanese osteoporotic women.

    PubMed

    Gannagé-Yared, Marie-Hélène; Maalouf, Ghassan; Khalife, Simon; Challita, Samir; Yaghi, Yasser; Ziade, Nelly; Chalfoun, Amal; Norquist, Josephine; Chandler, Julie

    2009-02-01

    In Middle-Eastern countries, more particularly in Lebanon, the incidence of vitamin D deficiency has been found to be surprisingly high in schoolchildren and young individuals. However, the prevalence and risk factors for vitamin D inadequacy amongst Lebanese osteoporotic women seeking medical health care has never been studied. We analysed vitamin D-inadequacy risk factors among the 251 Lebanese postmenopausal osteoporotic women (from both Muslim and Christian communities) who participated in a vitamin D international epidemiological study. Vitamin D inadequacy prevalence (25-hydroxyvitamin D (25(OH)D) , 30 ng/ml) was 84.9%. 25(OH)D was negatively correlated with BMI (r 20.41; P<0.001) and positively correlated with educational level (r 0.37; P<0.001) and self-reported general health (r 0.17; P<0.01). No significant correlation was found with age and no seasonal variation was observed. There was no significant correlation between 25(OH)D and sun exposure index or vitamin D-rich food consumption. However, 25(OH)D strongly correlated with vitamin D supplement intake (r 0.48; P<0.0001). Muslim community participants had lower 25(OH)D levels compared with their Christian counterparts (P<0.001). They also had higher BMI, lower educational level and vitamin D supplement consumption and followed more frequently a dress code covering the arms (P<0.0001 for all variables). In a multivariate model, in Muslims, inadequate vitamin D supplements and a dress code covering the arms are the independent predictors of 25(OH)D inadequacy (P<0.001 for both variables). However, in Christians, the predictors are inadequate vitamin D supplements, high BMI and low educational level (P<0.001; P=002 and P=0.02 respectively). There is an urgent need to increase vitamin D supplement use in Middle-Eastern osteoporotic women, more particularly in those from the Muslim community.

  15. Risk of nutrient inadequacies in elite Canadian athletes with spinal cord injury.

    PubMed

    Krempien, Jennifer L; Barr, Susan I

    2011-10-01

    Energy intakes of adults with spinal cord injury (SCI) have been reported to be relatively low, with many micronutrients below recommended amounts, but little is known about the diets of athletes with SCI. The purpose of this cross-sectional, observational study was to assess energy intakes and estimate the prevalence of dietary inadequacy in a sample of elite Canadian athletes with SCI (n = 32). Three-day self-reported food diaries completed at home and training camp were analyzed for energy (kcal), macronutrients, vitamins, and minerals and compared with the dietary reference intakes (DRIs). The prevalence of nutrient inadequacy was estimated by the proportion of athletes with mean intakes below the estimated average requirement (EAR). Energy intakes were 2,156 ± 431 kcal for men and 1,991 ± 510 kcal for women. Macronutrient intakes were within the acceptable macronutrient distribution ranges. While at training camp, >25% of men had intakes below the EAR for calcium, magnesium, zinc, riboflavin, folate, vitamin B12, and vitamin D. Thiamin, riboflavin, calcium, and vitamin D intakes were higher at home than training camp. Over 25% of women had intakes below the EAR for calcium, magnesium, folate, and vitamin D, with no significant differences in mean intakes between home and training camp. Vitamin/mineral supplement use significantly increased men's intakes of most nutrients but did not affect prevalence of inadequacy. Women's intakes did not change significantly with vitamin/mineral supplementation. These results demonstrate that athletes with SCI are at risk for several nutrient inadequacies relative to the DRIs.

  16. Current Inadequacy of Small Arms Training for All Military Occupational Specialties in the Conventional Army

    DTIC Science & Technology

    2007-11-02

    ABSTRACT This thesis examines the current inadequacy of small arms training for all military occupational specialties ( MOSs ) in the...to facilitate advanced, short-range, CQC like marksmanship training that will allow soldiers of all MOSs to dominate their 100 meters. Introduce Small...Member Dennis L . Dolan, Ph.D. , Member LTC Tony D. Baker, M.S. Accepted this 17th day of June 2005 by: , Director

  17. Towards Model Inadequacy Representations for Flamelet-Based RANS Combustion Simulations

    NASA Astrophysics Data System (ADS)

    Oliver, Todd; Lee, M. K.; Sondak, David; Simmons, Chris; Moser, Robert

    2016-11-01

    Flamelet-based RANS simulations are commonly used in combustion engineering. In such simulations, chemical reactions are represented by a "flamelet-library" of laminar diffusion flame solutions generated with some chemical mechanism, and turbulence is represented using typical eddy-viscosity-based RANS closures. Modeling errors are introduced through both of these models as well as their interaction. In this work, we formulate and apply physics-based stochastic model inadequacy representations to capture the effects of possible modeling errors, allowing their impact on quantities of interest to be estimated. Specifically, the uncertainty introduced by inadequacy of the chemical mechanism is represented using a recently developed stochastic operator approach, which is extended to the diffusion flame here, leading to a stochastic diffusion flame library. A Karhunen-Loeve decomposition applied to these random fields enables low-dimensional representation of this uncertainty. A stochastic extension of typical eddy-viscosity-based RANS models is developed to represent inadequacy in the turbulence closures. The full stochastic model is demonstrated on simulations of a planar jet flame.

  18. Micronutrient intakes and potential inadequacies of community-dwelling older adults: a systematic review.

    PubMed

    ter Borg, Sovianne; Verlaan, Sjors; Hemsworth, Jaimie; Mijnarends, Donja M; Schols, Jos M G A; Luiking, Yvette C; de Groot, Lisette C P G M

    2015-04-28

    Micronutrient deficiencies and low dietary intakes among community-dwelling older adults are associated with functional decline, frailty and difficulties with independent living. As such, studies that seek to understand the types and magnitude of potential dietary inadequacies might be beneficial for guiding future interventions. We carried out a systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Observational cohort and longitudinal studies presenting the habitual dietary intakes of older adults (≥65 years) were included. Sex-specific mean (and standard deviation) habitual micronutrient intakes were extracted from each article to calculate the percentage of older people who were at risk for inadequate micronutrient intakes using the estimated average requirement (EAR) cut-point method. The percentage at risk for inadequate micronutrient intakes from habitual dietary intakes was calculated for twenty micronutrients. A total of thirty-seven articles were included in the pooled systematic analysis. Of the twenty nutrients analysed, six were considered a possible public health concern: vitamin D, thiamin, riboflavin, Ca, Mg and Se. The extent to which these apparent inadequacies are relevant depends on dynamic factors, including absorption and utilisation, vitamin and mineral supplement use, dietary assessment methods and the selection of the reference value. In light of these considerations, the present review provides insight into the type and magnitude of vitamin and mineral inadequacies.

  19. Dietary diversity scores: an indicator of micronutrient inadequacy instead of obesity for Chinese children.

    PubMed

    Zhao, Wenzhi; Yu, Kai; Tan, Shengjie; Zheng, Yingdong; Zhao, Ai; Wang, Peiyu; Zhang, Yumei

    2017-05-12

    Micronutrient malnutrition affects the well-being of both adults and children. Dietary diversity score (DDS) is a useful evaluation index with a relatively well-developed guideline by FAO. It's meaningful to assess and predict inadequate micronutrient intakes using DDS in Chinese children, after ruling out the risk of obesity coming with more dietary diversity. Data for evaluation were extracted from the Nutrition Study of Preschool Children and School Children, which is a cross-sectional study covering 8 cities of China, including 1694 children in kindergartens and primary schools. This study applied DDS to Chinese children to test the validity for micronutrient inadequacy, and then explored the relationship between dietary diversity and obesity. It reveals that dietary diversity varied with age and place of residence; the older ones and the ones living in rural areas tend to have poorer dietary diversity. Another discovery is that DDS is positively correlated with indicators of micronutrient adequacy, with a score of 6-8 indicating the lowest risk of micronutrient inadequacy in different groups of children. In our study population, dietary diversity is not related with obesity. Dietary diversity score is a valid indicator to evaluate micronutrient inadequacy in Chinese children, though there is still room for improvement of the method. Besides, the relationship between increase of dietary diversity and risk of obesity should be treated circumspectly.

  20. Smoking and dietary inadequacy among Inuvialuit women of child bearing age in the Northwest Territories, Canada

    PubMed Central

    2013-01-01

    Objective The prevalence of smoking in Aboriginal Canadians is higher than non-Aboriginal Canadians, a behavior that also tends to alter dietary patterns. Compared with the general Canadian population, maternal smoking rates are almost twice as high. The aim of this study was to compare dietary adequacy of Inuvialuit women of childbearing age comparing smokers versus non-smokers. Research methods & procedures A cross-sectional study, where participants completed a culturally specific quantitative food frequency questionnaire. Non-parametric analysis was used to compare mean nutrient intake, dietary inadequacy and differences in nutrient density among smokers and non-smokers. Multiple logistic regression analyses were performed for key nutrients inadequacy and smoking status. Data was collected from three communities in the Beaufort Delta region of the Northwest Territories, Canada from randomly selected Inuvialuit women of childbearing age (19-44 years). Results Of 92 participants, 75% reported being smokers. There were no significant differences in age, BMI, marital status, education, number of people in household working and/or number of self employed, and physical activity between smokers and non-smokers. Non-parametric analysis showed no differences in nutrient intake between smokers and non-smokers. Logistic regression however revealed there was a positive association between smoking and inadequacies of vitamin C (OR = 2.91, 95% CI, 1.17-5.25), iron (OR = 3.16, 95% CI, 1.27-5.90), and zinc (OR = 2.78, 95% CI, 1.12-4.94). A high percentage of women (>60%), regardless of smoking status, did not meet the dietary recommendations for fiber, vitamin D, E and potassium. Conclusions This study provides evidence of inadequate dietary intake among Inuvialuit of childbearing age regardless of smoking behavior. PMID:23433392

  1. Inadequacy of vitamins and minerals among high-school pupils in Ouarzazate, Morocco.

    PubMed

    Anzid, Karim; Baali, Abdellatif; Vimard, Patrice; Levy-Desroches, Susan; Cherkaoui, Mohamed; López, Pilar Montero

    2014-08-01

    To assess micronutrient intakes and the prevalence of inadequacy in a sample of high-school pupils in Ouarzazate, Morocco. Food records were compiled over three non-consecutive days by pre-trained pupils. Micronutrient intakes were estimated using the DIAL software, adapted to include foods commonly eaten in Morocco. The prevalence of inadequacy was estimated by the proportion of individuals with intakes below the Estimated Average Requirement (EAR) for vitamins B12, A and K, thiamin, riboflavin, niacin, pyridoxine, folate, ascorbic acid, iodine, Ca, Mg and P; below the Adequate Intake (AI) level for pantothenic acid, biotin, Na and K; and using the probability approach for Fe. Data were adjusted for intra-individual variation with exclusion of under-reporters. Ouarzazate, a semi-urban region situated on the southern slopes of the High Atlas with little industrial development but an important tourism sector. A self-selected sample of 312 pupils aged 15-19 years from the five public high schools. After exclusion of under-reporters, 293 remained for analysis. The highest proportions of below-EAR/AI intakes were seen for pantothenic acid (girls 85·1 %, boys 78·0 %), biotin (boys 83·1 %, girls 79·4 %), thiamin (boys 66·9 %), folate (girls 93·1 %, boys 74·6 %), iodine (boys 94·9 %, girls 88·0 %) and Ca (girls 83·4 %, boys 74·6 %). Na intake was generally in excess whereas K intake was below the AI level. In general, girls had better-quality diets than boys, who appeared to consume more 'empty calories'. Our findings suggest that in this population of Moroccan adolescents, nutritional intervention and educational strategies are needed to promote healthy eating habits and correct micronutrient inadequacies. To provide reliable and precise estimates of nutrient intakes, an update of Moroccan food composition databases is urgently needed. We recommend that national authorities address these issues.

  2. The Prevalence of Micronutrient Deficiencies and Inadequacies in the Middle East and Approaches to Interventions

    PubMed Central

    Hwalla, Nahla; Al Dhaheri, Ayesha Salem; Radwan, Hadia; Alfawaz, Hanan Abdullah; Fouda, Mona A.; Al-Daghri, Nasser Mohammed; Zaghloul, Sahar; Blumberg, Jeffrey B.

    2017-01-01

    Micronutrient deficiencies and inadequacies constitute a global health issue, particularly among countries in the Middle East. The objective of this review is to identify micronutrient deficits in the Middle East and to consider current and new approaches to address this problem. Based on the availability of more recent data, this review is primarily focused on countries that are in advanced nutrition transition. Prominent deficits in folate, iron, and vitamin D are noted among children/adolescents, women of childbearing age, pregnant women, and the elderly. Reports indicate that food fortification in the region is sporadic and ineffective, and the use of dietary supplements is low. Nutrition monitoring in the region is limited, and gaps in relevant information present challenges for implementing new policies and approaches to address the problem. Government-sponsored initiatives are necessary to assess current dietary intakes/patterns, support nutrition education, and to reduce food insecurity, especially among vulnerable population groups. Public–private partnerships should be considered in targeting micronutrient fortification programs and supplementation recommendations as approaches to help alleviate the burden of micronutrient deficiencies and inadequacies in the Middle East. PMID:28273802

  3. Treatment inadequacy in primary and specialized care patients with depressive and/or anxiety disorders.

    PubMed

    Bet, Pierre M; Hugtenburg, Jacqueline G; Penninx, Brenda W J H; Balkom, Anton van; Nolen, Willem A; Hoogendijk, Witte J G

    2013-12-15

    All guidelines on major depressive disorder (MDD) and anxiety disorders recommend pharmacotherapy and/or psychological treatment for moderate to severe disease. The aim of this cross-sectional study was to investigate treatment inadequacy, both pharmacological and psychological, in a large naturalistic cohort of subjects with MDD and anxiety disorders from the Netherlands Study of Depression and Anxiety. All subjects with a current 6-month diagnosis were included (n=1662). Demographic data, clinical features and actual medication use were assessed in face-to-face interviews. In moderate to severe MDD, 43% of the subjects were not treated sufficiently with antidepressants or psychological treatment. In primary health care patients, this undertreatment was 70%. In moderate to severe anxiety disorders, 44% of the subjects were not treated sufficiently with antidepressants, benzodiazepines or psychological treatment. Among antidepressant users with moderate to severe MDD, 21% of the pharmacotherapy was inadequate with respect to drug choice, dose and every day use. Undertreatment and pharmacotherapeutic inadequacy are common in moderate to severe MDD and anxiety disorders. Both are more pronounced in primary care than in specialized care. This may be partly due to differences in disease recognition and help seeking behaviour. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  4. Negative Selection of Artificial Immune Applied to Voltage Inadequacy Detection in Distribution Networks

    NASA Astrophysics Data System (ADS)

    Delboni, Luiz Fernando; Zambroni da Silva, Antonio Carlos; Oliveira, Denisson Queiroz

    2015-04-01

    The problem of voltage control and reactive power management plays a crucial role on power system's operations. Particularly, detecting the most effective control actions to reduce the system loss and enhance the voltage profile is of major interest. This paper deals with system voltage inadequacy detection. To address this problem, artificial immune system is employed considering its negative selection mechanism. Its purpose is to monitor system operation data entry and check if the voltage level is within its operating values. In this sense, the user may define the range of control, so the proposed methodology may be useful for normal and emergency operating conditions. Corrective actions are undertaken if necessary. The IEEE 34 nodes distribution system is used to test the proposed methodology.

  5. Some inadequacies of the current human factors certification process of advanced aircraft technologies

    NASA Technical Reports Server (NTRS)

    Paries, Jean

    1994-01-01

    Automation related accidents or serious incidents are not limited to advanced technology aircraft. There is a full history of such accidents with conventional technology aircraft. However, this type of occurrence is far from sparing the newest 'glass cockpit' generation, and it even seems to be a growing contributor to its accident rate. Nevertheless, all these aircraft have been properly certificated according to the relevant airworthiness regulations. Therefore, there is a growing concern that with the technological advancement of air transport aircraft cockpits, the current airworthiness regulations addressing cockpit design and human factors may have reached some level of inadequacy. This paper reviews some aspects of the current airworthiness regulations and certification process related to human factors of cockpit design and focuses on questioning their ability to guarantee the intended safety objectives.

  6. Maternal child-feeding practices and dietary inadequacy of 4-year-old children.

    PubMed

    Durão, Catarina; Andreozzi, Valeska; Oliveira, Andreia; Moreira, Pedro; Guerra, António; Barros, Henrique; Lopes, Carla

    2015-09-01

    This study aimed to evaluate the association between maternal perceived responsibility and child-feeding practices and dietary inadequacy of 4-year-old children. We studied 4122 mothers and children enrolled in the population-based birth cohort - Generation XXI (Porto, Portugal). Mothers self-completed the Child Feeding Questionnaire and a scale on covert and overt control, and answered to a food frequency questionnaire in face-to-face interviews. Using dietary guidelines for preschool children, adequacy intervals were defined: fruit and vegetables (F&V) 4-7 times/day; dairy 3-5 times/day; meat and eggs 5-10 times/week; fish 2-4 times/week. Inadequacy was considered as below or above these cut-points. For energy-dense micronutrient-poor foods and beverages (EDF), a tolerable limit was defined (<6 times/week). Associations between maternal perceived responsibility and child-feeding practices (restriction, monitoring, pressure to eat, overt and covert control) and children's diet were examined by logistic regression models. After adjustment for maternal BMI, education, and diet, and children's characteristics (sex, BMI z-scores), restriction, monitoring, overt and covert control were associated with 11-18% lower odds of F&V consumption below the interval defined as adequate. Overt control was also associated with 24% higher odds of their consumption above it. Higher perceived responsibility was associated with higher odds of children consuming F&V and dairy above recommendations. Pressure to eat was positively associated with consumption of dairy above the adequate interval. Except for pressure to eat, maternal practices were associated with 14-27% lower odds of inadequate consumption of EDF. In conclusion, children whose mothers had higher levels of covert control, monitoring, and restriction were less likely to consume F&V below recommendations and EDF above tolerable limits. Higher overt control and pressure to eat were associated, respectively, with higher

  7. Controversies of Sex Re-assignment in Genetic Males with Congenital Inadequacy of the Penis.

    PubMed

    Raveenthiran, Venkatachalam

    2017-07-08

    Sex assignment in 46XY genetic male children with congenital inadequacy of the penis (CIP) is controversial. Traditionally, children with penile length less than 2 cm at birth are considered unsuitable to be raised as males. They are typically re-assigned to female-sex and feminizing genitoplasty is usually done in infancy. However, the concept of cerebral androgen imprinting has caused paradigm shift in the philosophy of sex re-assignment. Masculinization of the brain, rather than length of the penis, is the modern criterion of sex re-assignment in CIP. This review summarizes the current understanding of the complex issue. In 46XY children with CIP, male-sex assignment appears appropriate in non-hormonal conditions such as idiopathic micropenis, aphallia and exstrophy. Female-sex re-assignment appears acceptable in complete androgen insensitivity (CAIS), while partial androgen insensitivity syndrome (PAIS) patients are highly dissatisfied with the assignment of either sex. Children with 5-alpha reductase deficiency are likely to have spontaneous penile lengthening at puberty. Hence, they are better raised as males. Although female assignment is common in pure gonadal dysgenesis, long-term results are not known to justify the decision.

  8. Evaluation of Glucose Dehydrogenase and Pyrroloquinoline Quinine (pqq) Mutagenesis that Renders Functional Inadequacies in Host Plants.

    PubMed

    Naveed, Muhammad; Sohail, Younas; Khalid, Nauman; Ahmed, Iftikhar; Mumtaz, Abdul Samad

    2015-08-01

    The rhizospheric zone abutting plant roots usually clutches a wealth of microbes. In the recent past, enormous genetic resources have been excavated with potential applications in host plant interaction and ancillary aspects. Two Pseudomonas strains were isolated and identified through 16S rRNA and rpoD sequence analyses as P. fluorescens QAU67 and P. putida QAU90. Initial biochemical characterization and their root-colonizing traits indicated their potential role in plant growth promotion. Such aerobic systems, involved in gluconic acid production and phosphate solubilization, essentially require the pyrroloquinoline quinine (PQQ)- dependent glucose dehydrogenase (GDH) in the genome. The PCR screening and amplification of GDH and PQQ and subsequent induction of mutagenesis characterized their possible role as antioxidants as well as in growth promotion, as probed in vitro in lettuce and in vivo in rice, bean, and tomato plants. The results showed significant differences (p < or = 0.05) in parameters of plant height, fresh weight, and dry weight, etc., deciphering a clear and in fact complementary role of GDH and PQQ in plant growth promotion. Our study not only provides direct evidence of the in vivo role of GDH and PQQ in host plants but also reveals their functional inadequacy in the event of mutation at either of these loci.

  9. Cognitive phylogenies, the Darwinian logic of descent, and the inadequacy of cladistic thinking.

    PubMed

    Theofanopoulou, Constantina; Boeckx, Cedric

    2015-01-01

    There has been a reappraisal of phylogenetic issues in cognitive science, as reconstructing cognitive phylogenies has been considered a key for unveiling the cognitive novelties that set the stage for what makes humans special. In our opinion, the studies made until now have approached cognitive phylogenies in a non-optimal way, and we wish to both highlight their problems, drawing on recent considerations in philosophy of biology. The inadequacy of current visions on cognitive phylogenies stems from the influence of the traditional "linear cladograms," according to which every seemingly new or more sophisticated feature of a cognitive mechanism, viewed as a novelty, is represented as a node on top of the old and shared elements. We claim that this kind of cladograms does not succeed in depicting the complexity with which traits are distributed across species and, furthermore, that the labels of the nodes of these traditional representational systems fail to capture the "tinkering" nature of evolution. We argue that if we are to conceive of cognitive mechanisms in a multi-dimensional, bottom-up perspective, in accordance with the Darwinian logic of descent, we should rather focus on decomposing these mechanisms into lower-level, generic functions, which have the additional advantage of being implementable in neural matter, which ultimately produces cognition. Doing so renders current constructions of cognitive phylogenies otiose.

  10. Choline inadequacy impairs trophoblast function and vascularization in cultured human placental trophoblasts.

    PubMed

    Jiang, Xinyin; Jones, Sara; Andrew, Benjamin Y; Ganti, Anita; Malysheva, Olga V; Giallourou, Natasa; Brannon, Patsy M; Roberson, Mark S; Caudill, Marie A

    2014-08-01

    Maternal choline intake during gestation may influence placental function and fetal health outcomes. Specifically, we previously showed that supplemental choline reduced placental and maternal circulating concentrations of the anti-angiogenic factor, fms-like tyrosine kinase-1 (sFLT1), in pregnant women as well as sFLT1 production in cultured human trophoblasts. The current study aimed to quantify the effect of choline on a wider array of biomarkers related to trophoblast function and to elucidate possible mechanisms. Immortalized HTR-8/SVneo trophoblasts were cultured in different choline concentrations (8, 13, and 28 µM [control]) for 96-h and markers of angiogenesis, inflammation, apoptosis, and blood vessel formation were examined. Choline insufficiency altered the angiogenic profile, impaired in vitro angiogenesis, increased inflammation, induced apoptosis, increased oxidative stress, and yielded greater levels of protein kinase C (PKC) isoforms δ and ϵ possibly through increases in the PKC activators 1-stearoyl-2-arachidonoyl-sn-glycerol and 1-stearoyl-2-docosahexaenoyl-sn-glycerol. Notably, the addition of a PKC inhibitor normalized angiogenesis and apoptosis, and partially rescued the aberrant gene expression profile. Together these results suggest that choline inadequacy may contribute to placental dysfunction and the development of disorders related to placental insufficiency by activating PKC.

  11. Splitting methods for low Mach number Euler and Navier-Stokes equations

    NASA Technical Reports Server (NTRS)

    Abarbanel, Saul; Dutt, Pravir; Gottlieb, David

    1987-01-01

    Examined are some splitting techniques for low Mach number Euler flows. Shortcomings of some of the proposed methods are pointed out and an explanation for their inadequacy suggested. A symmetric splitting for both the Euler and Navier-Stokes equations is then presented which removes the stiffness of these equations when the Mach number is small. The splitting is shown to be stable.

  12. Is thyroid inadequacy during gestation a risk factor for adverse pregnancy and developmental outcomes?

    PubMed

    LaFranchi, Stephen H; Haddow, James E; Hollowell, Joseph G

    2005-01-01

    A workshop entitled, "The Impact of Maternal Thyroid Diseases on the Developing Fetus: Implications for Diagnosis, Treatment, and Screening," was held in Atlanta, Georgia, January 12-13, 2004. This paper reports on the individual session that examined thyroid inadequacy during gestation as a risk factor for adverse pregnancy and developmental outcomes. For this session the following papers were presented: "Adverse Pregnancy Outcomes"; "Thyroid Physiology in the Fetus"; "New England Data: Cretinism Revisited-Preventing Fetal Brain Damage when Mothers Have Subclinical Hypothyroidism"; "Dutch Data: Pregnancy, Maternal Thyroid (Dys)function and Outcome of the Offspring"; and "Report on the Wales Controlled Antenatal Thyroid Screening Study (CATS); A Prospective RCT." These presentations were formally discussed by invited respondents well as others in attendance. Salient points from this session about which there was agreement include the following. Maternal hypothyroidism is associated with complications of pregnancy and adverse effects on the fetus. These risks are greater in women with overt hypothyroidism compared to subclinical hypothyroidism, and also appear to be increased in women with euthyroid autoimmune thyroid disease. If maternal hypothyroidism is treated adequately, this appears to reduce the risk for adverse outcomes. The demonstration of a pattern of ontogeny of fetal cerebral cortex deiodinases and thyroid hormone receptors, beginning by 7-8 weeks' gestation, is circumstantial evidence that thyroid hormone plays an important role in fetal neurodevelopment. Significant fetal thyroid hormone production and secretion does not begin until approximately 20 weeks' gestation. If there is a significant role for thyroid hormone in fetal neurodevelopment before 20 weeks' gestation, it likely is of maternal origin. Studies demonstrate low levels of thyroxine in the fetal coelomic fluid and blood prior to 12-14 weeks' gestation. Published data consistently document

  13. Quality protein maize for Africa: closing the protein inadequacy gap in vulnerable populations.

    PubMed

    Nuss, Emily T; Tanumihardjo, Sherry A

    2011-05-01

    Africa shares a unique relationship with maize (Zea mays). After its introduction from New World explorers, maize was quickly adopted as the cornerstone of local cuisine, especially in sub-Saharan countries. Although maize provides macro- and micronutrients required for humans, it lacks adequate amounts of the essential amino acids lysine and tryptophan. For those consuming >50% of their daily energy from maize, pandemic protein malnutrition may exist. Severe protein and energy malnutrition increases susceptibility to life-threatening diseases such as tuberculosis and gastroenteritis. A nutritionally superior maize cultivar named quality protein maize (QPM) represents nearly one-half century of research dedicated to malnutrition eradication. Compared with traditional maize types, QPM has twice the amount of lysine and tryptophan, as well as protein bioavailability that rivals milk casein. Animal and human studies suggest that substituting QPM for common maize results in improved health. However, QPM's practical contribution to maize-subsisting populations remains unresolved. Herein, total protein and essential amino acid requirements recommended by the WHO and the Institute of Medicine were applied to estimate QPM target intake levels for young children and adults, and these were compared with mean daily maize intakes by African country. The comparisons revealed that ~100 g QPM is required for children to maintain adequacy of lysine, the most limiting amino acid, and nearly 500 g is required for adults. This represents a 40% reduction in maize intake relative to common maize to meet protein requirements. The importance of maize in Africa underlines the potential for QPM to assist in closing the protein inadequacy gap.

  14. Quality Protein Maize for Africa: Closing the Protein Inadequacy Gap in Vulnerable Populations12

    PubMed Central

    Nuss, Emily T.; Tanumihardjo, Sherry A.

    2011-01-01

    Africa shares a unique relationship with maize (Zea mays). After its introduction from New World explorers, maize was quickly adopted as the cornerstone of local cuisine, especially in sub-Saharan countries. Although maize provides macro- and micronutrients required for humans, it lacks adequate amounts of the essential amino acids lysine and tryptophan. For those consuming >50% of their daily energy from maize, pandemic protein malnutrition may exist. Severe protein and energy malnutrition increases susceptibility to life-threatening diseases such as tuberculosis and gastroenteritis. A nutritionally superior maize cultivar named quality protein maize (QPM) represents nearly one-half century of research dedicated to malnutrition eradication. Compared with traditional maize types, QPM has twice the amount of lysine and tryptophan, as well as protein bioavailability that rivals milk casein. Animal and human studies suggest that substituting QPM for common maize results in improved health. However, QPM’s practical contribution to maize-subsisting populations remains unresolved. Herein, total protein and essential amino acid requirements recommended by the WHO and the Institute of Medicine were applied to estimate QPM target intake levels for young children and adults, and these were compared with mean daily maize intakes by African country. The comparisons revealed that ∼100 g QPM is required for children to maintain adequacy of lysine, the most limiting amino acid, and nearly 500 g is required for adults. This represents a 40% reduction in maize intake relative to common maize to meet protein requirements. The importance of maize in Africa underlines the potential for QPM to assist in closing the protein inadequacy gap. PMID:22332054

  15. [Inadequacy of the content of prenatal care and associated factors in a cohort in the northeast of Brazil].

    PubMed

    Goudard, Marivanda Julia Furtado; Simões, Vanda Maria Ferreira; Batista, Rosângela Fernandes Lucena; Queiroz, Rejane Christine de Souza; Alves, Maria Tereza Seabra Soares de Brito E; Coimbra, Liberata Campos; Martins, Marília da Glória; Barbieri, Marco Antônio; Nathasje, Ian Favero

    2016-04-01

    The scope of this study was to analyze the content of prenatal care in São Luís, Maranhão, Brazil, and the factors associated with its inadequacy. A cross-sectional study was conducted based on data from the birth cohort of São Luís in 2010. The content of prenatal care was defined as inadequate when it did not meet the criteria of the Program for Humanization of Prenatal and Delivery Care, which establishes early initiation of prenatal care, minimum number of medical consultations, basic laboratory tests, tetanus vaccination and obstetric procedures. Poisson regression was used to observe associations of the variables with the outcome. The inadequacy rate was high (60.2%). The variables associated with inadequacy were: class C socioeconomic status (PR = 1.39; CI = 1.26-1.55); class D/E socioeconomic status (PR = 1.60; CI = 1.43-1.79); unqualified/unemployed mother (PR = 1.24; CI = 1.11-1.37); 5-8 years of schooling (PR = 1.12; CI = 1.06-1.19); 0-4 years of schooling (PR = 1.13; CI = 1.01-1.26); not being religious (PR = 1.10; CI = 1.04-1.17); alcohol use during pregnancy (PR = 1.13; CI = 1.06-1.20), and being attended by the public service (PR = 1.75; CI = 1.54-2.00). The results showed inadequacy and inequality of prenatal care, revealing that women of lower socioeconomic status received lower quality care.

  16. Racial/ethnic and sociodemographic factors associated with micronutrient intakes and inadequacies among pregnant women in an urban US population.

    PubMed

    Brunst, Kelly J; Wright, Robert O; DiGioia, Kimberly; Enlow, Michelle Bosquet; Fernandez, Harriet; Wright, Rosalind J; Kannan, Srimathi

    2014-09-01

    To assess sociodemographic correlates of micronutrient intakes from food and dietary supplements in an urban, ethnically diverse sample of pregnant women in the USA. Cross-sectional analyses of data collected using a validated semi-quantitative FFQ. Associations between racial, ethnic and sociodemographic factors and micronutrient intakes were examined using logistic regression controlling for pre-pregnancy BMI, maternal age and smoking status. Prenatal clinics, Boston, MA, USA. Analyses included pregnant women (n 274) in the PRogramming of Intergenerational Stress Mechanisms (PRISM) study, an urban longitudinal cohort designed to examine how stress influences respiratory health in children when controlling for other environmental exposures (chemical stressors, nutrition). High frequencies of vitamin E (52 %), Mg (38 %), Fe (57 %) and vitamin D (77 %) inadequacies as well as suboptimal intakes of choline (95 %) and K (99 %) were observed. Factors associated with multiple antioxidant inadequacies included being Hispanic or African American, lower education and self-reported economic-related food insecurity. Hispanics had a higher prevalence of multiple methyl-nutrient inadequacies compared with African Americans; both had suboptimal betaine intakes and higher odds for vitamin B₆ and Fe inadequacies compared with Caucasians. Nearly all women (98 %) reported Na intakes above the tolerable upper limit; excessive intakes of Mg (35 %), folate (37 %) and niacin (38 %) were also observed. Women reporting excessive intakes of these nutrients were more likely Caucasian or Hispanic, more highly educated, US-born and did not report food insecurity. Racial/ethnic and other sociodemographic factors should be considered when tailoring periconceptional dietary interventions for urban ethnic women in the USA.

  17. Inadequacies of Physical Examination as a Cause of Medical Errors and Adverse Events: A Collection of Vignettes.

    PubMed

    Verghese, Abraham; Charlton, Blake; Kassirer, Jerome P; Ramsey, Meghan; Ioannidis, John P A

    2015-12-01

    Oversights in the physical examination are a type of medical error not easily studied by chart review. They may be a major contributor to missed or delayed diagnosis, unnecessary exposure to contrast and radiation, incorrect treatment, and other adverse consequences. Our purpose was to collect vignettes of physical examination oversights and to capture the diversity of their characteristics and consequences. A cross-sectional study using an 11-question qualitative survey for physicians was distributed electronically, with data collected from February to June of 2011. The participants were all physicians responding to e-mail or social media invitations to complete the survey. There were no limitations on geography, specialty, or practice setting. Of the 208 reported vignettes that met inclusion criteria, the oversight was caused by a failure to perform the physical examination in 63%; 14% reported that the correct physical examination sign was elicited but misinterpreted, whereas 11% reported that the relevant sign was missed or not sought. Consequence of the physical examination inadequacy included missed or delayed diagnosis in 76% of cases, incorrect diagnosis in 27%, unnecessary treatment in 18%, no or delayed treatment in 42%, unnecessary diagnostic cost in 25%, unnecessary exposure to radiation or contrast in 17%, and complications caused by treatments in 4%. The mode of the number of physicians missing the finding was 2, but many oversights were missed by many physicians. Most oversights took up to 5 days to identify, but 66 took longer. Special attention and skill in examining the skin and its appendages, as well as the abdomen, groin, and genitourinary area could reduce the reported oversights by half. Physical examination inadequacies are a preventable source of medical error, and adverse events are caused mostly by failure to perform the relevant examination. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Early Career Teachers' Sense of Professional Agency in the Classroom: Associations with Turnover Intentions and Perceived Inadequacy in Teacher-Student Interaction

    ERIC Educational Resources Information Center

    Heikonen, Lauri; Pietarinen, Janne; Pyhältö, Kirsi; Toom, Auli; Soini, Tiina

    2017-01-01

    Teachers' capacity to learn intentionally and responsively in the classroom is particularly vulnerable during the first years in the profession. This study investigated the interrelations between early career teachers' turnover intentions, perceived inadequacy in teacher-student interaction, and sense of professional agency in the classroom. The…

  19. A weakly-constrained data assimilation approach to address rainfall-runoff model structural inadequacy in streamflow prediction

    NASA Astrophysics Data System (ADS)

    Lee, Haksu; Seo, Dong-Jun; Noh, Seong Jin

    2016-11-01

    This paper presents a simple yet effective weakly-constrained (WC) data assimilation (DA) approach for hydrologic models which accounts for model structural inadequacies associated with rainfall-runoff transformation processes. Compared to the strongly-constrained (SC) DA, WC DA adjusts the control variables less while producing similarly or more accurate analysis. Hence the adjusted model states are dynamically more consistent with those of the base model. The inadequacy of a rainfall-runoff model was modeled as an additive error to runoff components prior to routing and penalized in the objective function. Two example modeling applications, distributed and lumped, were carried out to investigate the effects of the WC DA approach on DA results. For distributed modeling, the distributed Sacramento Soil Moisture Accounting (SAC-SMA) model was applied to the TIFM7 Basin in Missouri, USA. For lumped modeling, the lumped SAC-SMA model was applied to nineteen basins in Texas. In both cases, the variational DA (VAR) technique was used to assimilate discharge data at the basin outlet. For distributed SAC-SMA, spatially homogeneous error modeling yielded updated states that are spatially much more similar to the a priori states, as quantified by Earth Mover's Distance (EMD), than spatially heterogeneous error modeling by up to ∼10 times. DA experiments using both lumped and distributed SAC-SMA modeling indicated that assimilating outlet flow using the WC approach generally produce smaller mean absolute difference as well as higher correlation between the a priori and the updated states than the SC approach, while producing similar or smaller root mean square error of streamflow analysis and prediction. Large differences were found in both lumped and distributed modeling cases between the updated and the a priori lower zone tension and primary free water contents for both WC and SC approaches, indicating possible model structural deficiency in describing low flows or

  20. On the (in)adequacy of the Charpy impact test to monitor irradiation effects of ferritic/martensitic steels

    NASA Astrophysics Data System (ADS)

    Chaouadi, R.

    2007-02-01

    Irradiation embrittlement studies rely very often on Charpy impact data, in particular the ductile-to-brittle transition temperature (DBTT). However, while the DBTT-shift is equivalent to the increase of the fracture toughness transition temperature of ferritic steels, it is not the case for ferritic/martensitic steels. The aim of this study is to critically assess experimental data obtained on a 9%Cr-ferritic/martensitic steel, Eurofer-97, to better understand the underlying mechanisms involved during the fracture process. More specifically, a dedicated analysis using the load diagram approach allows to unambiguously reveal the actual effects of irradiation on physically rather than empirically based parameters. A comparison is made between a ferritic and ferritic/martensitic steel to better identify the possible similarities and differences. Tensile, Charpy impact and fracture toughness tests data are examined in a global approach to assess the actual rather than apparent irradiation effects. The adequacy or inadequacy of the Charpy impact test to monitor irradiation effects is extensively discussed.

  1. Inadequacies of Dogmatic Realism

    DTIC Science & Technology

    1996-01-01

    OFIDEALISM Twentieth-century history testties that efforts to blend morahty and pohttcs have not only often fatled, but also have caused perverse effects...rational analysis of lustoncal evidence concernmg the behavior of mdlmduals and nation states. Oswald Spengler, the mfluentlal ktoncal pUosopher whose...to mtematlonal behavior There are no absolute values m the pohtical realm of the Reakt Each nation, culture, and society detemes its own values

  2. Dirac bubble potential for He-He and inadequacies in the continuum: Comparing an analytic model with elastic collision experiments.

    PubMed

    Chrysos, Michael

    2017-01-14

    We focus on the long-pending issue of the inadequacy of the Dirac bubble potential model in the description of He-He interactions in the continuum [L. L. Lohr and S. M. Blinder, Int. J. Quantum Chem. 53, 413 (1995)]. We attribute this failure to the lack of a potential wall to mimic the onset of the repulsive interaction at close range separations. This observation offers the explanation to why this excessively simple model proves incapable of quantitatively reproducing previous experimental findings of glory scattering in He-He, although being notorious for its capability of reproducing several distinctive features of the atomic and isotopic helium dimers and trimers [L. L. Lohr and S. M. Blinder, Int. J. Quantum Chem. 90, 419 (2002)]. Here, we show that an infinitely high, energy-dependent potential wall of properly calculated thickness rc(E) taken as a supplement to the Dirac bubble potential suffices for agreement with variable-energy elastic collision cross section experiments for (4)He-(4)He, (3)He-(4)He, and (3)He-(3)He [R. Feltgen et al., J. Chem. Phys. 76, 2360 (1982)]. In the very low energy regime, consistency is found between the Dirac bubble potential (to which our extended model is shown to reduce) and cold collision experiments [J. C. Mester et al., Phys. Rev. Lett. 71, 1343 (1993)]; this consistency, which in this regime lends credence to the Dirac bubble potential, was never noticed by its authors. The revised model being still analytic is of high didactical value while expected to increase in predictive power relative to other appraisals.

  3. Vitamin D inadequacy is widespread in Tunisian active boys and is related to diet but not to adiposity or insulin resistance

    PubMed Central

    Bezrati, Ikram; Ben Fradj, Mohamed Kacem; Ouerghi, Nejmeddine; Feki, Moncef; Chaouachi, Anis; Kaabachi, Naziha

    2016-01-01

    Background Vitamin D inadequacy is widespread in children and adolescents worldwide. The present study was undertaken to assess the vitamin D status in active children living in a sunny climate and to identify the main determinants of the serum concentration of 25-hydroxyvitamin D (25-OHD). Methods This cross-sectional study included 225 children aged 7–15 years practicing sports in a football academy. Anthropometric measures were performed to calculate body mass index (BMI), fat mass, and maturity status. A nutritional enquiry was performed including 3-day food records and food frequency questionnaire. Plasma 25-OHD and insulin were assessed by immunoenzymatic methods ensuring categorization of vitamin D status and calculation of insulin sensitivity/resistance indexes. A logistic regression model was applied to identify predictors for vitamin D inadequacy. Results Vitamin D deficiency (25-OHD<12 µg/L) was observed in 40.9% of children and insufficiency (12<25-OHD<20 µg/L) was observed in 44% of children. In a multivariate analysis, vitamin D deficiency and insufficiency were associated with a lower dietary intake of vitamin D, proteins, milk, red meat, fish, and eggs. However, no significant relationship was observed with maturation status, adiposity, or insulin resistance. Conclusions Tunisian children and adolescents are exposed to a high risk of vitamin D inadequacy despite living in a sunny climate. Circulating 25-OHD concentrations are related to the intake of vitamin D food sources but not to maturation status or body composition. Ensuring sufficient and safe sun exposure and adequate vitamin D intake may prevent vitamin D inadequacy in children from sunny environments. PMID:27113441

  4. Penetration equations

    SciTech Connect

    Young, C.W.

    1997-10-01

    In 1967, Sandia National Laboratories published empirical equations to predict penetration into natural earth materials and concrete. Since that time there have been several small changes to the basic equations, and several more additions to the overall technique for predicting penetration into soil, rock, concrete, ice, and frozen soil. The most recent update to the equations was published in 1988, and since that time there have been changes in the equations to better match the expanding data base, especially in concrete penetration. This is a standalone report documenting the latest version of the Young/Sandia penetration equations and related analytical techniques to predict penetration into natural earth materials and concrete. 11 refs., 6 tabs.

  5. Basic Equations

    NASA Astrophysics Data System (ADS)

    Britz, Dieter

    In this chapter, we present most of the equations that apply to the systems and processes to be dealt with later. Most of these are expressed as equations of concentration dynamics, that is,concentration of one or more solution species as a function of time, as well as other variables, in the form of differential equations. Fundamentally, these are transport (diffusion-, convection- and migration-) equations but may be complicated by chemical processes occurring heterogeneously (i.e. at the electrode surface - electrochemical reaction) or homogeneously (in the solution bulk - chemical reaction). The transport components are all included in the general Nernst-Planck equation (see also Bard and Faulkner 2001) for the flux J j of species j

  6. Equation poems

    NASA Astrophysics Data System (ADS)

    Prentis, Jeffrey J.

    1996-05-01

    One of the most challenging goals of a physics teacher is to help students see that the equations of physics are connected to each other, and that they logically unfold from a small number of basic ideas. Derivations contain the vital information on this connective structure. In a traditional physics course, there are many problem-solving exercises, but few, if any, derivation exercises. Creating an equation poem is an exercise to help students see the unity of the equations of physics, rather than their diversity. An equation poem is a highly refined and eloquent set of symbolic statements that captures the essence of the derivation of an equation. Such a poetic derivation is uncluttered by the extraneous details that tend to distract a student from understanding the essential physics of the long, formal derivation.

  7. Multiple B-vitamin inadequacy amplifies alterations induced by folate depletion in p53 expression and its downstream effector MDM2

    PubMed Central

    Liu, Zhenhua; Choi, Sang-Woon; Crott, Jimmy W.; Smith, Donald E.; Mason, Joel B.

    2009-01-01

    Folate is required for biological methylation and nucleotide synthesis, aberrations of which are thought to be the mechanisms that enhance colorectal carcinogenesis produced by folate inadequacy. These functions of folate also depend on the availability of other B-vitamins that participate in “one-carbon metabolism,” including B2, B6 and B12. Our study therefore investigated whether combined dietary restriction of these vitamins amplifies aberrations in the epigenetic and genetic integrity of the p53 gene that is induced by folate depletion alone. Ninety-six mice were group pair-fed diets with different combinations of B-vitamin depletion over 10 weeks. DNA and RNA were extracted from epithelial cells isolated from the colon. Within the hypermutable region of p53 (exons 5–8), DNA strand breaks were induced within exons 6 and 8 by folate combined with B2, B6 and B12 restriction (p < 0.05); such effects were not significantly induced by mild folate depletion alone. Similarly, a minor degree of hypomethylation of exon 6 produced by isolated folate depletion was significantly amplified (p ≤ 0.05) by simultaneous depletion of all 4 B-vitamins. Furthermore, the expression of p53 and MDM2 were significantly decreased (p ≤ 0.05) by the combined depletion state but not by folate depletion alone. These data indicate that inadequacies of other 1-carbon vitamins may amplify aberrations of the p53 gene induced by folate depletion alone, implying that concurrent inadequacies in several of these vitamins may have added tumorigenic potential beyond that observed with isolated folate depletion. PMID:18498130

  8. Beautiful equations

    NASA Astrophysics Data System (ADS)

    Viljamaa, Panu; Jacobs, J. Richard; Chris; JamesHyman; Halma, Matthew; EricNolan; Coxon, Paul

    2014-07-01

    In reply to a Physics World infographic (part of which is given above) about a study showing that Euler's equation was deemed most beautiful by a group of mathematicians who had been hooked up to a functional magnetic-resonance image (fMRI) machine while viewing mathematical expressions (14 May, http://ow.ly/xHUFi).

  9. Marcus equation

    DOE R&D Accomplishments Database

    1998-09-21

    In the late 1950s to early 1960s Rudolph A. Marcus developed a theory for treating the rates of outer-sphere electron-transfer reactions. Outer-sphere reactions are reactions in which an electron is transferred from a donor to an acceptor without any chemical bonds being made or broken. (Electron-transfer reactions in which bonds are made or broken are referred to as inner-sphere reactions.) Marcus derived several very useful expressions, one of which has come to be known as the Marcus cross-relation or, more simply, as the Marcus equation. It is widely used for correlating and predicting electron-transfer rates. For his contributions to the understanding of electron-transfer reactions, Marcus received the 1992 Nobel Prize in Chemistry. This paper discusses the development and use of the Marcus equation. Topics include self-exchange reactions; net electron-transfer reactions; Marcus cross-relation; and proton, hydride, atom and group transfers.

  10. Adequacy of the virial equation of state and cluster expansion

    NASA Astrophysics Data System (ADS)

    Ushcats, M. V.

    2013-04-01

    The limits for the accuracy of the virial expansion and the problem of its divergence have been investigated using the exact cluster expansion of the configuration integral. In the subcritical temperature regimes the virial equation of state is applicable up to the singularity point of the isothermal compressibility, i.e., to the possible beginning of the condensation process. At supercritical temperatures this equation should be applicable within the region where the cluster expansion is adequate. The problem of the virial series divergence has been found to be irrelevant to the actual behavior of the cluster expansion. Considering the Lennard-Jones fluid as well as the system of hard spheres, the inadequate behavior of the cluster expansion has been discovered in the high density regime. The major reason for this inadequacy should be the basic simplification of the cluster expansion: the integration of irreducible diagrams over the infinite limits.

  11. Adequacy of the virial equation of state and cluster expansion.

    PubMed

    Ushcats, M V

    2013-04-01

    The limits for the accuracy of the virial expansion and the problem of its divergence have been investigated using the exact cluster expansion of the configuration integral. In the subcritical temperature regimes the virial equation of state is applicable up to the singularity point of the isothermal compressibility, i.e., to the possible beginning of the condensation process. At supercritical temperatures this equation should be applicable within the region where the cluster expansion is adequate. The problem of the virial series divergence has been found to be irrelevant to the actual behavior of the cluster expansion. Considering the Lennard-Jones fluid as well as the system of hard spheres, the inadequate behavior of the cluster expansion has been discovered in the high density regime. The major reason for this inadequacy should be the basic simplification of the cluster expansion: the integration of irreducible diagrams over the infinite limits.

  12. Combined inadequacies of multiple B vitamins amplify colonic Wnt signaling and promote intestinal tumorigenesis in BAT-LacZ×Apc1638N mice

    PubMed Central

    Liu, Zhenhua; Ciappio, Eric D.; Crott, Jimmy W.; Brooks, Ryan S.; Nesvet, Jared; Smith, Donald E.; Choi, Sang-Woon; Mason, Joel B.

    2011-01-01

    The Wnt pathway is a pivotal signaling cascade in colorectal carcinogenesis. The purpose of this work is to determine whether depletion of folate and other metabolically related B vitamins induces in vivo activation of intestinal Wnt signaling and whether this occurs in parallel with increased tumorigenesis. A hybrid mouse was created by crossing a Wnt-reporter animal (BAT-LacZ) with a model of colorectal cancer (Apc1638N). A mild depletion of folate and vitamins B2, B6, and B12 was induced over 16 wk, and the control animals in each instance were pair fed a diet containing the basal requirement of these nutrients. The multiplicity of macroscopic tumors and aberrant crypt foci both increased by ∼50% in the hybrid mice fed the depletion diet (P<0.05). A 4-fold elevation in Wnt signaling was produced by the depletion diet (P<0.05) and was accompanied by significant changes in the expression of a number of Wnt-related genes in a pattern consistent with its activation. Proliferation and apoptosis of the colonic mucosa both changed in a protransformational direction (P<0.05). In summary, mild depletion of multiple B vitamins produces in vivo activation of colonic Wnt signaling, implicating it as a key pathway by which B-vitamin inadequacies enhance intestinal tumorigenesis.—Liu, Z., Ciappio, E. D., Crott, J. W., Brooks, R. S., Nesvet, J., Smith, D. E., Choi, S.-W., Mason, J. B. Combined inadequacies of multiple B vitamins amplify colonic Wnt signaling and promote intestinal tumorigenesis in BAT-LacZ×Apc1638N mice. PMID:21646397

  13. Equational Abstractions

    DTIC Science & Technology

    2007-01-01

    A b. Given an arbitrary relation→, we write →• for the total relation that extends→ by adding a pair a→• a for each a such that there is no b with a→ b...kind of a sort s is denoted by [s]. We write TΣ,k and TΣ,k(~x) to denote respectively the set of ground Σ-terms with kind k and of Σ-terms with kind k...variables. In membership equational logic, subsort relations and operator overloading are just a convenient way of writing corresponding Horn clauses

  14. Movement and effects of spilled oil over the outer continental shelf; inadequacy of existent data for the Baltimore Canyon Trough area

    USGS Publications Warehouse

    Knebel, Harley J.

    1974-01-01

    A deductive approach to the problem of determining the movement and effects of spilled oil over the Outer Continental Shelf requires that the potential paths of oil be determined first, in order that critical subareas may be defined for later studies. The paths of spilled oil, in turn, depend primarily on the temporal and spatial variability of four factors: the thermohaline structure of the waters, the circulation of the water, the winds, and the distribution of suspended matter. A review of the existent data concerning these factors for the Baltimore Canyon Trough area (a relatively well studied segment of the Continental Shelf) reveals that the movement and dispersal of potential oil spills cannot be reliably predicted. Variations in the thermohaline structure of waters and in the distribution of suspended matter are adequately known; the uncertainty is due to insufficient wind and storm statistics and to the lack of quantitative understanding of the relationship between the nontidal drift and its basic driving mechanisms. Similar inadequacies should be anticipated for other potentially leasable areas of the shelf because an understanding of the movement of spilled oil has not been the underlying aim of most previous studies.

  15. Circulating tumour cells: the evolving concept and the inadequacy of their enrichment by EpCAM-based methodology for basic and clinical cancer research.

    PubMed

    Grover, P K; Cummins, A G; Price, T J; Roberts-Thomson, I C; Hardingham, J E

    2014-08-01

    Increasing evidence suggests that circulating tumour cells (CTCs) are responsible for metastatic relapse and this has fuelled interest in their detection and quantification. Although numerous methods have been developed for the enrichment and detection of CTCs, none has yet reached the 'gold' standard. Since epithelial cell adhesion molecule (EpCAM)-based enrichment of CTCs offers several advantages, it is one of the most commonly used and has been adapted for high-throughput technology. However, emerging evidence suggests that CTCs are highly heterogeneous: they consist of epithelial tumour cells, epithelial-to-mesenchymal transition (EMT) cells, hybrid (epithelial/EMT(+)) tumour cells, irreversible EMT(+) tumour cells, and circulating tumour stem cells (CTSCs). The EpCAM-based approach does not detect CTCs expressing low levels of EpCAM and non-epithelial phenotypes such as CTSCs and those that have undergone EMT and no longer express EpCAM. Thus, the approach may lead to underestimation of the significance of CTCs, in general, and CTSCs and EMT(+) tumour cells, in particular, in cancer dissemination. Here, we provide a critical review of research literature on the evolving concept of CTCs and the inadequacy of their enrichment by EpCAM-based technology for basic and clinical cancer research. The review also outlines future perspectives in the field. © The Author 2014. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  16. Extended rate equations

    SciTech Connect

    Shore, B.W.

    1981-01-30

    The equations of motion are discussed which describe time dependent population flows in an N-level system, reviewing the relationship between incoherent (rate) equations, coherent (Schrodinger) equations, and more general partially coherent (Bloch) equations. Approximations are discussed which replace the elaborate Bloch equations by simpler rate equations whose coefficients incorporate long-time consequences of coherence.

  17. Equating Error in Observed-Score Equating

    ERIC Educational Resources Information Center

    van der Linden, Wim J.

    2006-01-01

    Traditionally, error in equating observed scores on two versions of a test is defined as the difference between the transformations that equate the quantiles of their distributions in the sample and population of test takers. But it is argued that if the goal of equating is to adjust the scores of test takers on one version of the test to make…

  18. Basic lubrication equations

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.; Dowson, D.

    1981-01-01

    Lubricants, usually Newtonian fluids, are assumed to experience laminar flow. The basic equations used to describe the flow are the Navier-Stokes equation of motion. The study of hydrodynamic lubrication is, from a mathematical standpoint, the application of a reduced form of these Navier-Stokes equations in association with the continuity equation. The Reynolds equation can also be derived from first principles, provided of course that the same basic assumptions are adopted in each case. Both methods are used in deriving the Reynolds equation, and the assumptions inherent in reducing the Navier-Stokes equations are specified. Because the Reynolds equation contains viscosity and density terms and these properties depend on temperature and pressure, it is often necessary to couple the Reynolds with energy equation. The lubricant properties and the energy equation are presented. Film thickness, a parameter of the Reynolds equation, is a function of the elastic behavior of the bearing surface. The governing elasticity equation is therefore presented.

  19. Variational Derivation of Dissipative Equations

    NASA Astrophysics Data System (ADS)

    Sogo, Kiyoshi

    2017-03-01

    A new variational principle is formulated to derive various dissipative equations. Model equations considered are the damping equation, Bloch equation, diffusion equation, Fokker-Planck equation, Kramers equation and Smoluchowski equation. Each equation and its time reversal equation are simultaneously obtained in our variational principle.

  20. Simplex and Polygon Equations

    NASA Astrophysics Data System (ADS)

    Dimakis, Aristophanes; Müller-Hoissen, Folkert

    2015-06-01

    It is shown that higher Bruhat orders admit a decomposition into a higher Tamari order, the corresponding dual Tamari order, and a ''mixed order''. We describe simplex equations (including the Yang-Baxter equation) as realizations of higher Bruhat orders. Correspondingly, a family of ''polygon equations'' realizes higher Tamari orders. They generalize the well-known pentagon equation. The structure of simplex and polygon equations is visualized in terms of deformations of maximal chains in posets forming 1-skeletons of polyhedra. The decomposition of higher Bruhat orders induces a reduction of the N-simplex equation to the (N+1)-gon equation, its dual, and a compatibility equation.

  1. Household food insecurity is associated with a higher burden of obesity and risk of dietary inadequacies among mothers in Beirut, Lebanon.

    PubMed

    Jomaa, Lamis; Naja, Farah; Cheaib, Ruba; Hwalla, Nahla

    2017-06-12

    Mixed evidence exists with respect to the association between household food insecurity (HFIS) and obesity in low-to-middle income countries (LMICs), particularly among women. This study aimed to measure socioeconomic correlates of HFIS and explores its association with dietary intake and odds of obesity among mothers in Lebanon, a middle-income country undergoing nutrition transition. A cross-sectional study was conducted among a representative sample of households (n = 378) in Beirut, Lebanon. Surveys were completed with mothers of children <18 years. HFIS was measured using a locally-validated, Arabic-translated Household Food Insecurity Access Scale (HFIAS). Dietary intake was assessed using the multiple pass 24-h recall method. Associations between HFIS (food vs food insecure) and socio-demographic characteristics were reported using crude and adjusted odds ratios. The odds of consuming <2/3rd Dietary Reference Intakes (DRIs) for nutrients among mothers from food secure and food insecure households were explored. In addition, logistic regression analyses were conducted to explore the association of HFIS with obesity (BMI ≥ 30 kg/m2) and at-risk waist circumference (WC ≥ 80 cm) among mothers. HFIS was found among 50% of study sample and was inversely associated with household income and mother's educational level, even after adjusting for other socioeconomic variables (p < 0.01). Mothers in food insecure households reported consuming significantly less dairy products, fruits, and nuts yet more breads and sweets; and they had higher odds of consuming <2/3rd the DRI's for key micronutrients (potassium, folate, and vitamin C) compared to secure ones. Adjusting for socioeconomic correlates, food insecure mothers had 1.73 odds of obesity (95% CI: 1.02-2.92) compared to food secure mothers. High HFIS prevalence was reported among urban Lebanese households. Mothers from food insecure households had a high risk of dietary inadequacy and obesity. Adequate

  2. Modeling Demonstrates That Folic Acid Fortification of Whole-Wheat Flour Could Reduce the Prevalence of Folate Inadequacy in Canadian Whole-Wheat Consumers.

    PubMed

    Chan, Yen-Ming; MacFarlane, Amanda J; O'Connor, Deborah L

    2015-11-01

    Mandatory folic acid fortification of white-wheat flour and selected other grain products has reduced the prevalence of neural tube defects in Canada; however, the fortification of whole-wheat flour is not permitted. The objective of this study was to model the impact of adding folic acid to whole-wheat flour on the folate intake distribution of Canadians. Twenty-four-hour dietary recall and supplement intake data (n = 35,107) collected in the 2004 Canadian Community Health Survey 2.2 were used to calculate the prevalence of folate inadequacy (POFI) and the proportion of folic acid intakes above the Tolerable Upper Intake Level (UL). In model 1, folic acid was added to whole-wheat flour-containing foods in amounts comparable to those that are mandatory for white-wheat flour-containing foods. In model 2, a 50% overage of folic acid fortification was considered. Models 3 and 4 included assessment of folate intake distributions in adult whole-wheat consumers with or without a fortification overage. SIDE (Software for Intake Distribution Estimation; Department of Statistics and Center for Agricultural and Rural Development, Iowa State University) was used to estimate usual folate intakes. Mean folate intakes increased by ∼ 5% in all sex and age groups when whole-wheat foods were fortified (models 1 and 2; P < 0.0001). Folic acid fortification of whole-wheat flour-containing foods did not change the POFI or percentage of intakes above the UL in the general population, whether in supplement users or nonusers. Among whole-wheat consumers, the POFI was reduced by 10 percentage points after fortification of whole-wheat flour-containing foods (95% CIs did not overlap). The percentage of whole-wheat consumers with intakes above the UL did not change. Although folic acid fortification of whole-wheat flour-containing foods is unlikely to change the POFI or proportion of folic acid intakes above the UL in the general Canadian population, this fortification strategy may reduce

  3. Chemical Equation Balancing.

    ERIC Educational Resources Information Center

    Blakley, G. R.

    1982-01-01

    Reviews mathematical techniques for solving systems of homogeneous linear equations and demonstrates that the algebraic method of balancing chemical equations is a matter of solving a system of homogeneous linear equations. FORTRAN programs using this matrix method to chemical equation balancing are available from the author. (JN)

  4. Kinetic energy equations for the average-passage equation system

    NASA Technical Reports Server (NTRS)

    Johnson, Richard W.; Adamczyk, John J.

    1989-01-01

    Important kinetic energy equations derived from the average-passage equation sets are documented, with a view to their interrelationships. These kinetic equations may be used for closing the average-passage equations. The turbulent kinetic energy transport equation used is formed by subtracting the mean kinetic energy equation from the averaged total instantaneous kinetic energy equation. The aperiodic kinetic energy equation, averaged steady kinetic energy equation, averaged unsteady kinetic energy equation, and periodic kinetic energy equation, are also treated.

  5. Kinetic balance and variational bounds failure in the solution of the Dirac equation in a finite Gaussian basis set

    NASA Technical Reports Server (NTRS)

    Dyall, Kenneth G.; Faegri, Knut, Jr.

    1990-01-01

    The paper investigates bounds failure in calculations using Gaussian basis sets for the solution of the one-electron Dirac equation for the 2p1/2 state of Hg(79+). It is shown that bounds failure indicates inadequacies in the basis set, both in terms of the exponent range and the number of functions. It is also shown that overrepresentation of the small component space may lead to unphysical results. It is concluded that it is important to use matched large and small component basis sets with an adequate size and exponent range.

  6. Kinetic balance and variational bounds failure in the solution of the Dirac equation in a finite Gaussian basis set

    NASA Technical Reports Server (NTRS)

    Dyall, Kenneth G.; Faegri, Knut, Jr.

    1990-01-01

    The paper investigates bounds failure in calculations using Gaussian basis sets for the solution of the one-electron Dirac equation for the 2p1/2 state of Hg(79+). It is shown that bounds failure indicates inadequacies in the basis set, both in terms of the exponent range and the number of functions. It is also shown that overrepresentation of the small component space may lead to unphysical results. It is concluded that it is important to use matched large and small component basis sets with an adequate size and exponent range.

  7. Turbulent flow past a backward-facing step - A critical evaluation of two-equation models

    NASA Technical Reports Server (NTRS)

    Thangam, S.; Speziale, C. G.

    1992-01-01

    The ability of two-equation models to accurately predict separated flows is analyzed from a combined theoretical and computational standpoint. Turbulent flow past a backward facing step is chosen as a test case in an effort to resolve the variety of conflicting results that were published during the past decade concerning the performance of two-equation models. It is found that the errors in the reported predictions of the k-epsilon model have two major origins: (1) numerical problems arising from inadequate resolution, and (2) inaccurate predictions for normal Reynolds stress differences arising from the use of an isotropic eddy viscosity. Inadequacies in near wall modelling play a substantially smaller role. Detailed calculations are presented which strongly indicate the standard k-epsilon model - when modified with an independently calibrated anisotropic eddy viscosity - can yield surprisingly good predictions for the backstep problem.

  8. Single wall penetration equations

    NASA Technical Reports Server (NTRS)

    Hayashida, K. B.; Robinson, J. H.

    1991-01-01

    Five single plate penetration equations are compared for accuracy and effectiveness. These five equations are two well-known equations (Fish-Summers and Schmidt-Holsapple), two equations developed by the Apollo project (Rockwell and Johnson Space Center (JSC), and one recently revised from JSC (Cour-Palais). They were derived from test results, with velocities ranging up to 8 km/s. Microsoft Excel software was used to construct a spreadsheet to calculate the diameters and masses of projectiles for various velocities, varying the material properties of both projectile and target for the five single plate penetration equations. The results were plotted on diameter versus velocity graphs for ballistic and spallation limits using Cricket Graph software, for velocities ranging from 2 to 15 km/s defined for the orbital debris. First, these equations were compared to each other, then each equation was compared with various aluminum projectile densities. Finally, these equations were compared with test results performed at JSC for the Marshall Space Flight Center. These equations predict a wide variety of projectile diameters at a given velocity. Thus, it is very difficult to choose the 'right' prediction equation. The thickness of a single plate could have a large variation by choosing a different penetration equation. Even though all five equations are empirically developed with various materials, especially for aluminum alloys, one cannot be confident in the shield design with the predictions obtained by the penetration equations without verifying by tests.

  9. Interpretation of Bernoulli's Equation.

    ERIC Educational Resources Information Center

    Bauman, Robert P.; Schwaneberg, Rolf

    1994-01-01

    Discusses Bernoulli's equation with regards to: horizontal flow of incompressible fluids, change of height of incompressible fluids, gases, liquids and gases, and viscous fluids. Provides an interpretation, properties, terminology, and applications of Bernoulli's equation. (MVL)

  10. Reflections on Chemical Equations.

    ERIC Educational Resources Information Center

    Gorman, Mel

    1981-01-01

    The issue of how much emphasis balancing chemical equations should have in an introductory chemistry course is discussed. The current heavy emphasis on finishing such equations is viewed as misplaced. (MP)

  11. Random equations in aerodynamics

    NASA Technical Reports Server (NTRS)

    Bharucha-Reid, A. T.

    1984-01-01

    Literature was reviewed to identify aerodynamic models which might be treated by probablistic methods. The numerical solution of some integral equations that arise in aerodynamical problems were investigated. On the basis of the numerical studies a qualitative theory of random integral equations was developed to provide information on the behavior of the solutions of these equations (in particular, boundary and asymptotic behavior, and stability) and their statistical properties without actually obtaining explicit solutions of the equations.

  12. Parametrically defined differential equations

    NASA Astrophysics Data System (ADS)

    Polyanin, A. D.; Zhurov, A. I.

    2017-01-01

    The paper deals with nonlinear ordinary differential equations defined parametrically by two relations. It proposes techniques to reduce such equations, of the first or second order, to standard systems of ordinary differential equations. It obtains the general solution to some classes of nonlinear parametrically defined ODEs dependent on arbitrary functions. It outlines procedures for the numerical solution of the Cauchy problem for parametrically defined differential equations.

  13. Integrable nonlinear relativistic equations

    NASA Astrophysics Data System (ADS)

    Hadad, Yaron

    This work focuses on three nonlinear relativistic equations: the symmetric Chiral field equation, Einstein's field equation for metrics with two commuting Killing vectors and Einstein's field equation for diagonal metrics that depend on three variables. The symmetric Chiral field equation is studied using the Zakharov-Mikhailov transform, with which its infinitely many local conservation laws are derived and its solitons on diagonal backgrounds are studied. It is also proven that it is equivalent to a novel equation that poses a fascinating similarity to the Sinh-Gordon equation. For the 1+1 Einstein equation the Belinski-Zakharov transformation is explored. It is used to derive explicit formula for N gravitational solitons on arbitrary diagonal background. In particular, the method is used to derive gravitational solitons on the Einstein-Rosen background. The similarities and differences between the attributes of the solitons of the symmetric Chiral field equation and those of the 1+1 Einstein equation are emphasized, and their origin is pointed out. For the 1+2 Einstein equation, new equations describing diagonal metrics are derived and their compatibility is proven. Different gravitational waves are studied that naturally extend the class of Bondi-Pirani-Robinson waves. It is further shown that the Bondi-Pirani-Robinson waves are stable with respect to perturbations of the spacetime. Their stability is closely related to the stability of the Schwarzschild black hole and the relation between the two allows to conjecture about the stability of a wide range of gravitational phenomena. Lastly, a new set of equations that describe weak gravitational waves is derived. This new system of equations is closely and fundamentally connected with the nonlinear Schrodinger equation and can be properly called the nonlinear Schrodinger-Einstein equations. A few preliminary solutions are constructed.

  14. The Pendulum Equation

    ERIC Educational Resources Information Center

    Fay, Temple H.

    2002-01-01

    We investigate the pendulum equation [theta] + [lambda][squared] sin [theta] = 0 and two approximations for it. On the one hand, we suggest that the third and fifth-order Taylor series approximations for sin [theta] do not yield very good differential equations to approximate the solution of the pendulum equation unless the initial conditions are…

  15. The Prevalence of Micronutrient Deficiencies and  Inadequacies in the Middle East and Approaches to  Interventions.

    PubMed

    Hwalla, Nahla; Al Dhaheri, Ayesha Salem; Radwan, Hadia; Alfawaz, Hanan Abdullah; Fouda, Mona A; Al-Daghri, Nasser Mohammed; Zaghloul, Sahar; Blumberg, Jeffrey B

    2017-03-03

    Micronutrient deficiencies and inadequacies constitute a global health issue, particularly among countries in the Middle East. The objective of this review is to identify micronutrient deficits in the Middle East and to consider current and new approaches to address this problem. Based on the availability of more recent data, this review is primarily focused on countries that are in advanced nutrition transition. Prominent deficits in folate, iron, and vitamin D are noted among children/adolescents, women of childbearing age, pregnant women, and the elderly. Reports indicate that food fortification in the region is sporadic and ineffective, and the use of dietary supplements is low. Nutrition monitoring in the region is limited, and gaps in relevant information present challenges for implementing new policies and approaches to address the problem. Government-sponsored initiatives are necessary to assess current dietary intakes/patterns, support nutrition education, and to reduce food insecurity, especially among vulnerable population groups. Public-private partnerships should be considered in targeting micronutrient fortification programs and supplementation recommendations as approaches to help alleviate the burden of micronutrient deficiencies and inadequacies in the Middle East.

  16. The bioavailability of iron, zinc, protein and vitamin A is highly variable in French individual diets: Impact on nutrient inadequacy assessment and relation with the animal-to-plant ratio of diets.

    PubMed

    Perignon, Marlène; Barré, Tangui; Gazan, Rozenn; Amiot, Marie-Josèphe; Darmon, Nicole

    2018-01-01

    Nutritional adequacy depends on nutrient intakes and bioavailability which strongly varies with the plant- or animal-origin of foods. The aim was to estimate iron, zinc, protein and vitamin A bioavailability from individual diets, and investigate its relation with the animal-to-plant ratio (A/P) of diets. Bioavailability was estimated in 1899 French diets using diet-based algorithms or food-group specific conversion factors. Nutrient inadequacy was estimated based on i) bioavailability calculated in each individual diet and ii) average bioavailability assumed for Western-diets. Mean iron absorption, zinc absorption, protein quality and β-carotene conversion factor were 13%, 30%, 92%, and 17:1, respectively. Bioavailability displayed a high variability between individual diets, poorly explained by their A/P. Using individual bioavailability led to different inadequacy prevalence than with average factors assumed for Western-diets. In this population, the A/P does not seem sufficient to predict nutrient bioavailability and the corresponding recommended intakes. Nutritional adequacy should be assessed using bioavailability accounting for individual diets composition. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. The SQG Equation as a Geodesic Equation

    NASA Astrophysics Data System (ADS)

    Washabaugh, Pearce

    2016-12-01

    We demonstrate that the surface quasi-geostrophic (SQG) equation given by θ_t + < u, nabla θrangle = 0,quad θ = nabla × (-Δ)^{-1/2} u, is the geodesic equation on the group of volume-preserving diffeomorphisms of a Riemannian manifold M in the right-invariant {dot{H}^{-1/2}} metric. We show by example, that the Riemannian exponential map is smooth and non-Fredholm, and that the sectional curvature at the identity is unbounded of both signs.

  18. Fractional chemotaxis diffusion equations.

    PubMed

    Langlands, T A M; Henry, B I

    2010-05-01

    We introduce mesoscopic and macroscopic model equations of chemotaxis with anomalous subdiffusion for modeling chemically directed transport of biological organisms in changing chemical environments with diffusion hindered by traps or macromolecular crowding. The mesoscopic models are formulated using continuous time random walk equations and the macroscopic models are formulated with fractional order differential equations. Different models are proposed depending on the timing of the chemotactic forcing. Generalizations of the models to include linear reaction dynamics are also derived. Finally a Monte Carlo method for simulating anomalous subdiffusion with chemotaxis is introduced and simulation results are compared with numerical solutions of the model equations. The model equations developed here could be used to replace Keller-Segel type equations in biological systems with transport hindered by traps, macromolecular crowding or other obstacles.

  19. Functional BES equation

    NASA Astrophysics Data System (ADS)

    Kostov, Ivan; Serban, Didina; Volin, Dmytro

    2008-08-01

    We give a realization of the Beisert, Eden and Staudacher equation for the planar Script N = 4 supersymetric gauge theory which seems to be particularly useful to study the strong coupling limit. We are using a linearized version of the BES equation as two coupled equations involving an auxiliary density function. We write these equations in terms of the resolvents and we transform them into a system of functional, instead of integral, equations. We solve the functional equations perturbatively in the strong coupling limit and reproduce the recursive solution obtained by Basso, Korchemsky and Kotański. The coefficients of the strong coupling expansion are fixed by the analyticity properties obeyed by the resolvents.

  20. Solving Ordinary Differential Equations

    NASA Technical Reports Server (NTRS)

    Krogh, F. T.

    1987-01-01

    Initial-value ordinary differential equation solution via variable order Adams method (SIVA/DIVA) package is collection of subroutines for solution of nonstiff ordinary differential equations. There are versions for single-precision and double-precision arithmetic. Requires fewer evaluations of derivatives than other variable-order Adams predictor/ corrector methods. Option for direct integration of second-order equations makes integration of trajectory problems significantly more efficient. Written in FORTRAN 77.

  1. Television Tracker Range Equation

    NASA Astrophysics Data System (ADS)

    Huan-Wen, Zhu

    1987-05-01

    The paper gives an approximate television tracker range equation based on the concept of the radiology and signal-to-noise of television system, and describes the physical process and mathematical method of reckoning range equation. The range equation is useful to the desing and development of a system. This paper also discusses the demand and selection standard of the television tracker system to the imaging device and gives some possible approaches to increase the range.

  2. Rubel's universal differential equation

    PubMed Central

    Duffin, R. J.

    1981-01-01

    Fourth-order differential equations such as 16y′my′2 - 32ymyny′ + 17y03 = 0 are developed. It is shown that the equation is “universal” in the sense that any continuous function can be approximated with arbitrary accuracy over the whole x axis by a solution y(x) of the equation. This solution is a piecewise polynomial of degree 9 and of class C4. PMID:16593068

  3. Hyperbolic type transport equations

    NASA Astrophysics Data System (ADS)

    García-Colín, L. S.; Olivares-Robles, M. A.

    1995-02-01

    In recent years hyperbolic type transport equations have acquired a great deal of importance in problems ranging from theoretical physics to biology. In spite of their greater mathematical difficulty as compared with their parabolic type analogs arising from the framework of Linear Irreversible Thermodynamics, they have, in many ways, superseded the latter ones. Although the use of this type of equations is well known since the last century through the telegraphist equation of electromagnetic theory, their use in studying several problems in transport theory is hardly fifty years old. In fact the first appearance of a hyperbolic type transport equation for the problem of heat conduction dates back to Cattaneos' work in 1948. Three years later, in 1951 S. Goldstein showed how in the theory of stochastic processes this type of an equation is obtained in the continuous limit of a one-dimensional persistent random walk problem. After that, other phenomenological derivations have been offered for such equations. The main purpose of this paper is to critically discuss a derivation of a hyperbolic type Fokker-Planck equation recently presented using the same ideas as M.S. Green did in 1952 to provide the stochastic foundations of irreversible statistical mechanics. Arguments are given to show that such an equation as well as transport equations derived from it by taking appropriate averages are at most approximate and that a much more detailed analysis is required before asserting their validity.

  4. Linear Equations: Equivalence = Success

    ERIC Educational Resources Information Center

    Baratta, Wendy

    2011-01-01

    The ability to solve linear equations sets students up for success in many areas of mathematics and other disciplines requiring formula manipulations. There are many reasons why solving linear equations is a challenging skill for students to master. One major barrier for students is the inability to interpret the equals sign as anything other than…

  5. Reduced Braginskii equations

    SciTech Connect

    Yagi, M.; Horton, W. )

    1994-07-01

    A set of reduced Braginskii equations is derived without assuming flute ordering and the Boussinesq approximation. These model equations conserve the physical energy. It is crucial at finite [beta] that the perpendicular component of Ohm's law be solved to ensure [del][center dot][bold j]=0 for energy conservation.

  6. Uniqueness of Maxwell's Equations.

    ERIC Educational Resources Information Center

    Cohn, Jack

    1978-01-01

    Shows that, as a consequence of two feasible assumptions and when due attention is given to the definition of charge and the fields E and B, the lowest-order equations that these two fields must satisfy are Maxwell's equations. (Author/GA)

  7. Reduced Braginskii equations

    SciTech Connect

    Yagi, M.; Horton, W.

    1993-11-01

    A set of reduced Braginskii equations is derived without assuming flute ordering and the Boussinesq approximation. These model equations conserve the physical energy. It is crucial at finite {beta} that we solve the perpendicular component of Ohm`s law to conserve the physical energy while ensuring the relation {del} {center_dot} j = 0.

  8. Functional Cantor equation

    NASA Astrophysics Data System (ADS)

    Shabat, A. B.

    2016-12-01

    We consider the class of entire functions of exponential type in relation to the scattering theory for the Schrödinger equation with a finite potential that is a finite Borel measure. These functions have a special self-similarity and satisfy q-difference functional equations. We study their asymptotic behavior and the distribution of zeros.

  9. Uniqueness of Maxwell's Equations.

    ERIC Educational Resources Information Center

    Cohn, Jack

    1978-01-01

    Shows that, as a consequence of two feasible assumptions and when due attention is given to the definition of charge and the fields E and B, the lowest-order equations that these two fields must satisfy are Maxwell's equations. (Author/GA)

  10. Biofortified β-carotene rice improves vitamin A intake and reduces the prevalence of inadequacy among women and young children in a simulated analysis in Bangladesh, Indonesia, and the Philippines1

    PubMed Central

    Angeles-Agdeppa, Imelda; Atmarita, Atmarita; Gironella, Glen M; Muslimatun, Siti; Carriquiry, Alicia

    2016-01-01

    Background: Vitamin A deficiency continues to be a major public health problem affecting developing countries where people eat mostly rice as a staple food. In Asia, rice provides up to 80% of the total daily energy intake. Objective: We used existing data sets from Bangladesh, Indonesia, and the Philippines, where dietary intakes have been quantified at the individual level to 1) determine the rice and vitamin A intake in nonpregnant, nonlactating women of reproductive age and in nonbreastfed children 1–3 y old and 2) simulate the amount of change that could be achieved in the prevalence of inadequate intake of vitamin A if rice biofortified with β-carotene were consumed instead of the rice consumed at present. Design: We considered a range of 4–20 parts per million (ppm) of β-carotene content and 10–70% substitution levels for the biofortified rice. Software was used to estimate usual rice and vitamin A intake for the simulation analyses. Results: In an analysis by country, the substitution of biofortified rice for white rice in the optimistic scenario (20 ppm and 70% substitution) decreased the prevalence of vitamin A inadequacy from baseline 78% in women and 71% in children in Bangladesh. In Indonesia and the Philippines, the prevalence of inadequacy fell by 55–60% in women and dropped by nearly 30% in children from baseline. Conclusions: The results of the simulation analysis were striking in that even low substitution levels and modest increases in the β-carotene of rice produced a meaningful decrease in the prevalence of inadequate intake of vitamin A. Increasing the substitution levels had a greater impact than increasing the β-carotene content by >12 ppm. PMID:27510534

  11. Biofortified β-carotene rice improves vitamin A intake and reduces the prevalence of inadequacy among women and young children in a simulated analysis in Bangladesh, Indonesia, and the Philippines.

    PubMed

    De Moura, Fabiana F; Moursi, Mourad; Donahue Angel, Moira; Angeles-Agdeppa, Imelda; Atmarita, Atmarita; Gironella, Glen M; Muslimatun, Siti; Carriquiry, Alicia

    2016-09-01

    Vitamin A deficiency continues to be a major public health problem affecting developing countries where people eat mostly rice as a staple food. In Asia, rice provides up to 80% of the total daily energy intake. We used existing data sets from Bangladesh, Indonesia, and the Philippines, where dietary intakes have been quantified at the individual level to 1) determine the rice and vitamin A intake in nonpregnant, nonlactating women of reproductive age and in nonbreastfed children 1-3 y old and 2) simulate the amount of change that could be achieved in the prevalence of inadequate intake of vitamin A if rice biofortified with β-carotene were consumed instead of the rice consumed at present. We considered a range of 4-20 parts per million (ppm) of β-carotene content and 10-70% substitution levels for the biofortified rice. Software was used to estimate usual rice and vitamin A intake for the simulation analyses. In an analysis by country, the substitution of biofortified rice for white rice in the optimistic scenario (20 ppm and 70% substitution) decreased the prevalence of vitamin A inadequacy from baseline 78% in women and 71% in children in Bangladesh. In Indonesia and the Philippines, the prevalence of inadequacy fell by 55-60% in women and dropped by nearly 30% in children from baseline. The results of the simulation analysis were striking in that even low substitution levels and modest increases in the β-carotene of rice produced a meaningful decrease in the prevalence of inadequate intake of vitamin A. Increasing the substitution levels had a greater impact than increasing the β-carotene content by >12 ppm.

  12. Charged-particle transport in gases in electric and magnetic fields crossed at arbitrary angles: Multiterm solution of Boltzmann's equation.

    PubMed

    White, R D; Ness, K F; Robson, R E; Li, B

    1999-08-01

    A multiterm solution of the Boltzmann equation has been developed and used to calculate transport coefficients of charged-particle swarms in gases under the influence of electric and magnetic fields crossed at arbitrary angles psi. The hierarchy resulting from a spherical harmonic decomposition of the Boltzmann equation in the hydrodynamic regime [Ness, Phys. Rev. A 47, 327 (1993)] is solved numerically by representing the speed dependence of the phase-space distribution function in terms of an expansion in Sonine polynomials about a weighted sum of Maxwellian distributions at different temperatures. Results are given for charged-particle swarms in certain model gases over a range of psi and field strengths. The variation of the transport coefficients with psi is addressed using physical arguments. The errors associated with the two-term approximation and inadequacies of Legendre polynomial expansions are highlighted.

  13. Turbulent separated flow past a backward-facing step: A critical evaluation of two-equation turbulence models

    NASA Technical Reports Server (NTRS)

    Thangam, S.; Speziale, C. G.

    1991-01-01

    The ability of two-equation models to accurately predict separated flows is analyzed from a combined theoretical and computational standpoint. Turbulent flow past a backward facing step is chosen as a test case in an effort to resolve the variety of conflicting results that were published during the past decade concerning the performance of two-equation models. It is found that the errors in the reported predictions of the k-epsilon model have two major origins: (1) numerical problems arising from inadequate resolution, and (2) inaccurate predictions for normal Reynolds stress differences arising from the use of an isotropic eddy viscosity. Inadequacies in near wall modelling play a substantially smaller role. Detailed calculations are presented which strongly indicate the standard k-epsilon model - when modified with an independently calibrated anisotropic eddy viscosity - can yield surprisingly good predictions for the backstep problem.

  14. The Effective Equation Method

    NASA Astrophysics Data System (ADS)

    Kuksin, Sergei; Maiocchi, Alberto

    In this chapter we present a general method of constructing the effective equation which describes the behavior of small-amplitude solutions for a nonlinear PDE in finite volume, provided that the linear part of the equation is a hamiltonian system with a pure imaginary discrete spectrum. The effective equation is obtained by retaining only the resonant terms of the nonlinearity (which may be hamiltonian, or may be not); the assertion that it describes the limiting behavior of small-amplitude solutions is a rigorous mathematical theorem. In particular, the method applies to the three- and four-wave systems. We demonstrate that different possible types of energy transport are covered by this method, depending on whether the set of resonances splits into finite clusters (this happens, e.g. in case of the Charney-Hasegawa-Mima equation), or is connected (this happens, e.g. in the case of the NLS equation if the space-dimension is at least two). For equations of the first type the energy transition to high frequencies does not hold, while for equations of the second type it may take place. Our method applies to various weakly nonlinear wave systems, appearing in plasma, meteorology and oceanography.

  15. Nonlinear gyrokinetic equations

    SciTech Connect

    Dubin, D.H.E.; Krommes, J.A.; Oberman, C.; Lee, W.W.

    1983-03-01

    Nonlinear gyrokinetic equations are derived from a systematic Hamiltonian theory. The derivation employs Lie transforms and a noncanonical perturbation theory first used by Littlejohn for the simpler problem of asymptotically small gyroradius. For definiteness, we emphasize the limit of electrostatic fluctuations in slab geometry; however, there is a straight-forward generalization to arbitrary field geometry and electromagnetic perturbations. An energy invariant for the nonlinear system is derived, and various of its limits are considered. The weak turbulence theory of the equations is examined. In particular, the wave kinetic equation of Galeev and Sagdeev is derived from an asystematic truncation of the equations, implying that this equation fails to consider all gyrokinetic effects. The equations are simplified for the case of small but finite gyroradius and put in a form suitable for efficient computer simulation. Although it is possible to derive the Terry-Horton and Hasegawa-Mima equations as limiting cases of our theory, several new nonlinear terms absent from conventional theories appear and are discussed.

  16. The Quadrature Master Equations

    NASA Astrophysics Data System (ADS)

    Hassan, N. J.; Pourdarvish, A.; Sadeghi, J.; Olaomi, J. O.

    2017-04-01

    In this paper, we derive the non-Markovian stochastic equation of motion (SEM) and master equations (MEs) for the open quantum system by using the non-Markovian stochastic Schrödinger equations (SSEs) for the quadrature unraveling in linear and nonlinear cases. The SSEs for quadrature unraveling arise as a special case of a quantum system. Also we derive the Markovian SEM and ME by using linear and nonlinear Itô SSEs for the measurement probabilities. In linear non-Markovian case, we calculate the convolutionless linear quadrature non-Markovian SEM and ME. We take advantage from example and show that corresponding theory.

  17. Nonlinear ordinary difference equations

    NASA Technical Reports Server (NTRS)

    Caughey, T. K.

    1979-01-01

    Future space vehicles will be relatively large and flexible, and active control will be necessary to maintain geometrical configuration. While the stresses and strains in these space vehicles are not expected to be excessively large, their cumulative effects will cause significant geometrical nonlinearities to appear in the equations of motion, in addition to the nonlinearities caused by material properties. Since the only effective tool for the analysis of such large complex structures is the digital computer, it will be necessary to gain a better understanding of the nonlinear ordinary difference equations which result from the time discretization of the semidiscrete equations of motion for such structures.

  18. A Comparison of IRT Equating and Beta 4 Equating.

    ERIC Educational Resources Information Center

    Kim, Dong-In; Brennan, Robert; Kolen, Michael

    Four equating methods were compared using four equating criteria: first-order equity (FOE), second-order equity (SOE), conditional mean squared error (CMSE) difference, and the equipercentile equating property. The four methods were: (1) three parameter logistic (3PL) model true score equating; (2) 3PL observed score equating; (3) beta 4 true…

  19. Concerning the equation of state for partially ionized system

    SciTech Connect

    Baker, Jr, George A

    2008-01-01

    I will discuss the expansion of various thermodynamic quantities about the ideal gas in powers of the electric charge, and I will discuss some cellular models. The first type of cellular model is appropriate for hydrogen. The second type is for Z > 1. It has the independent electron approximation within the atoms. These models are cross compared and minimal regions of validity are determined. The actual region of validity is expected to be larger. In the cellular models, the phase boundaries for liquid-gas transitions are found. For the second type of cellular model, in the part of the low-temperature, low-density region where there is not much expectation of validity of these methods, a non-thermodynamic region is found. I have devised a construction, similar in spirit to the Maxwell construction, to bridge this region so as to leave a thermodynamically valid equation of state. The non-thermodynamic region does not occur in hydrogen and it seems to be due to the inadequacy of the aforementioned approximation in that region.

  20. Regularized Structural Equation Modeling.

    PubMed

    Jacobucci, Ross; Grimm, Kevin J; McArdle, John J

    A new method is proposed that extends the use of regularization in both lasso and ridge regression to structural equation models. The method is termed regularized structural equation modeling (RegSEM). RegSEM penalizes specific parameters in structural equation models, with the goal of creating easier to understand and simpler models. Although regularization has gained wide adoption in regression, very little has transferred to models with latent variables. By adding penalties to specific parameters in a structural equation model, researchers have a high level of flexibility in reducing model complexity, overcoming poor fitting models, and the creation of models that are more likely to generalize to new samples. The proposed method was evaluated through a simulation study, two illustrative examples involving a measurement model, and one empirical example involving the structural part of the model to demonstrate RegSEM's utility.

  1. Nonlinear differential equations

    SciTech Connect

    Dresner, L.

    1988-01-01

    This report is the text of a graduate course on nonlinear differential equations given by the author at the University of Wisconsin-Madison during the summer of 1987. The topics covered are: direction fields of first-order differential equations; the Lie (group) theory of ordinary differential equations; similarity solutions of second-order partial differential equations; maximum principles and differential inequalities; monotone operators and iteration; complementary variational principles; and stability of numerical methods. The report should be of interest to graduate students, faculty, and practicing scientists and engineers. No prior knowledge is required beyond a good working knowledge of the calculus. The emphasis is on practical results. Most of the illustrative examples are taken from the fields of nonlinear diffusion, heat and mass transfer, applied superconductivity, and helium cryogenics.

  2. Equations For Rotary Transformers

    NASA Technical Reports Server (NTRS)

    Salomon, Phil M.; Wiktor, Peter J.; Marchetto, Carl A.

    1988-01-01

    Equations derived for input impedance, input power, and ratio of secondary current to primary current of rotary transformer. Used for quick analysis of transformer designs. Circuit model commonly used in textbooks on theory of ac circuits.

  3. Solving Equations Today.

    ERIC Educational Resources Information Center

    Shumway, Richard J.

    1989-01-01

    Illustrated is the problem of solving equations and some different strategies students might employ when using available technology. Gives illustrations for: exact solutions, approximate solutions, and approximate solutions which are graphically generated. (RT)

  4. Discrete wave equation upscaling

    NASA Astrophysics Data System (ADS)

    Fichtner, Andreas; Hanasoge, Shravan M.

    2017-01-01

    We present homogenisation technique for the uniformly discretised wave equation, based on the derivation of an effective equation for the low-wavenumber component of the solution. The method produces a down-sampled, effective medium, thus making the solution of the effective equation less computationally expensive. Advantages of the method include its conceptual simplicity and ease of implementation, the applicability to any uniformly discretised wave equation in one, two or three dimensions, and the absence of any constraints on the medium properties. We illustrate our method with a numerical example of wave propagation through a one-dimensional multiscale medium, and demonstrate the accurate reproduction of the original wavefield for sufficiently low frequencies.

  5. SIMULTANEOUS DIFFERENTIAL EQUATION COMPUTER

    DOEpatents

    Collier, D.M.; Meeks, L.A.; Palmer, J.P.

    1960-05-10

    A description is given for an electronic simulator for a system of simultaneous differential equations, including nonlinear equations. As a specific example, a homogeneous nuclear reactor system including a reactor fluid, heat exchanger, and a steam boiler may be simulated, with the nonlinearity resulting from a consideration of temperature effects taken into account. The simulator includes three operational amplifiers, a multiplier, appropriate potential sources, and interconnecting R-C networks.

  6. Relativistic Guiding Center Equations

    SciTech Connect

    White, R. B.; Gobbin, M.

    2014-10-01

    In toroidal fusion devices it is relatively easy that electrons achieve relativistic velocities, so to simulate runaway electrons and other high energy phenomena a nonrelativistic guiding center formalism is not sufficient. Relativistic guiding center equations including flute mode time dependent field perturbations are derived. The same variables as used in a previous nonrelativistic guiding center code are adopted, so that a straightforward modifications of those equations can produce a relativistic version.

  7. Photonic Equations of Motion

    SciTech Connect

    Ritchie, A B; Crenshaw, M E

    2004-09-17

    Although the concept of the photon as a quantum particle is sharpened by the quantization of the energy of the classical radiation field in a cavity, the photon's spin has remained a classical degree of freedom. The photon is considered a spin-1 particle, although only two classical polarization states transverse to its direction of propagation are allowed. Effectively therefore the photon is a spin-1/2 particle, although it still obeys Bose-Einstein statistics because the photon-photon interaction is zero. Here they show that the two polarization states of the photon can be quantized using Pauli's spin vector, such that a suitable equation of motion for the photon is Dirac's relativistic wave equation for zero mass and zero charge. Maxwell's equations for a free photon are inferred from the Dirac-field formalism and thus provide proof of this claim. For photons in the presence of electronic sources for electromagnetic fields we posit Lorentz-invariant inhomogeneous photonic equations of motion. Electro-dynamic operator equations are inferred from this modified Dirac-field formalism which reduce to Maxwell's equations if spin-dependent terms in the radiation-matter interaction are dropped.

  8. The Bernoulli-Poiseuille Equation.

    ERIC Educational Resources Information Center

    Badeer, Henry S.; Synolakis, Costas E.

    1989-01-01

    Describes Bernoulli's equation and Poiseuille's equation for fluid dynamics. Discusses the application of the combined Bernoulli-Poiseuille equation in real flows, such as viscous flows under gravity and acceleration. (YP)

  9. The Bernoulli-Poiseuille Equation.

    ERIC Educational Resources Information Center

    Badeer, Henry S.; Synolakis, Costas E.

    1989-01-01

    Describes Bernoulli's equation and Poiseuille's equation for fluid dynamics. Discusses the application of the combined Bernoulli-Poiseuille equation in real flows, such as viscous flows under gravity and acceleration. (YP)

  10. Spatial equation for water waves

    NASA Astrophysics Data System (ADS)

    Dyachenko, A. I.; Zakharov, V. E.

    2016-02-01

    A compact spatial Hamiltonian equation for gravity waves on deep water has been derived. The equation is dynamical and can describe extreme waves. The equation for the envelope of a wave train has also been obtained.

  11. Introducing Chemical Formulae and Equations.

    ERIC Educational Resources Information Center

    Dawson, Chris; Rowell, Jack

    1979-01-01

    Discusses when the writing of chemical formula and equations can be introduced in the school science curriculum. Also presents ways in which formulae and equations learning can be aided and some examples for balancing and interpreting equations. (HM)

  12. Lindblad rate equations

    SciTech Connect

    Budini, Adrian A.

    2006-11-15

    In this paper we derive an extra class of non-Markovian master equations where the system state is written as a sum of auxiliary matrixes whose evolution involve Lindblad contributions with local coupling between all of them, resembling the structure of a classical rate equation. The system dynamics may develop strong nonlocal effects such as the dependence of the stationary properties with the system initialization. These equations are derived from alternative microscopic interactions, such as complex environments described in a generalized Born-Markov approximation and tripartite system-environment interactions, where extra unobserved degrees of freedom mediates the entanglement between the system and a Markovian reservoir. Conditions that guarantee the completely positive condition of the solution map are found. Quantum stochastic processes that recover the system dynamics in average are formulated. We exemplify our results by analyzing the dynamical action of nontrivial structured dephasing and depolarizing reservoirs over a single qubit.

  13. Parallel tridiagonal equation solvers

    NASA Technical Reports Server (NTRS)

    Stone, H. S.

    1974-01-01

    Three parallel algorithms were compared for the direct solution of tridiagonal linear systems of equations. The algorithms are suitable for computers such as ILLIAC 4 and CDC STAR. For array computers similar to ILLIAC 4, cyclic odd-even reduction has the least operation count for highly structured sets of equations, and recursive doubling has the least count for relatively unstructured sets of equations. Since the difference in operation counts for these two algorithms is not substantial, their relative running times may be more related to overhead operations, which are not measured in this paper. The third algorithm, based on Buneman's Poisson solver, has more arithmetic operations than the others, and appears to be the least favorable. For pipeline computers similar to CDC STAR, cyclic odd-even reduction appears to be the most preferable algorithm for all cases.

  14. Nonlocal electrical diffusion equation

    NASA Astrophysics Data System (ADS)

    Gómez-Aguilar, J. F.; Escobar-Jiménez, R. F.; Olivares-Peregrino, V. H.; Benavides-Cruz, M.; Calderón-Ramón, C.

    2016-07-01

    In this paper, we present an analysis and modeling of the electrical diffusion equation using the fractional calculus approach. This alternative representation for the current density is expressed in terms of the Caputo derivatives, the order for the space domain is 0<β≤1 and for the time domain is 0<γ≤2. We present solutions for the full fractional equation involving space and time fractional derivatives using numerical methods based on Fourier variable separation. The case with spatial fractional derivatives leads to Levy flight type phenomena, while the time fractional equation is related to sub- or super diffusion. We show that the mathematical concept of fractional derivatives can be useful to understand the behavior of semiconductors, the design of solar panels, electrochemical phenomena and the description of anomalous complex processes.

  15. Obtaining Maxwell's equations heuristically

    NASA Astrophysics Data System (ADS)

    Diener, Gerhard; Weissbarth, Jürgen; Grossmann, Frank; Schmidt, Rüdiger

    2013-02-01

    Starting from the experimental fact that a moving charge experiences the Lorentz force and applying the fundamental principles of simplicity (first order derivatives only) and linearity (superposition principle), we show that the structure of the microscopic Maxwell equations for the electromagnetic fields can be deduced heuristically by using the transformation properties of the fields under space inversion and time reversal. Using the experimental facts of charge conservation and that electromagnetic waves propagate with the speed of light, together with Galilean invariance of the Lorentz force, allows us to finalize Maxwell's equations and to introduce arbitrary electrodynamics units naturally.

  16. Kepler Equation solver

    NASA Technical Reports Server (NTRS)

    Markley, F. Landis

    1995-01-01

    Kepler's Equation is solved over the entire range of elliptic motion by a fifth-order refinement of the solution of a cubic equation. This method is not iterative, and requires only four transcendental function evaluations: a square root, a cube root, and two trigonometric functions. The maximum relative error of the algorithm is less than one part in 10(exp 18), exceeding the capability of double-precision computer arithmetic. Roundoff errors in double-precision implementation of the algorithm are addressed, and procedures to avoid them are developed.

  17. Stochastic differential equations

    SciTech Connect

    Sobczyk, K. )

    1990-01-01

    This book provides a unified treatment of both regular (or random) and Ito stochastic differential equations. It focuses on solution methods, including some developed only recently. Applications are discussed, in particular an insight is given into both the mathematical structure, and the most efficient solution methods (analytical as well as numerical). Starting from basic notions and results of the theory of stochastic processes and stochastic calculus (including Ito's stochastic integral), many principal mathematical problems and results related to stochastic differential equations are expounded here for the first time. Applications treated include those relating to road vehicles, earthquake excitations and offshore structures.

  18. Ordinary Differential Equations

    NASA Astrophysics Data System (ADS)

    Britz, Dieter

    In this chapter, the numerical solution of ordinary differential equations (odes) will be described. There is a direct connection between this area and that of partial differential equations (pdes), as noted in, for example [558]. The ode field is large; but here we restrict ourselves to those techniques that appear again in the pde field. Readers wishing greater depth than is presented here can find it in the great number of texts on the subject, such as the classics by Lapidus & Seinfeld [351], Gear [264] or Jain [314];there is a very clear chapter in Gerald [266].

  19. Accumulative Equating Error after a Chain of Linear Equatings

    ERIC Educational Resources Information Center

    Guo, Hongwen

    2010-01-01

    After many equatings have been conducted in a testing program, equating errors can accumulate to a degree that is not negligible compared to the standard error of measurement. In this paper, the author investigates the asymptotic accumulative standard error of equating (ASEE) for linear equating methods, including chained linear, Tucker, and…

  20. Comparison of Kernel Equating and Item Response Theory Equating Methods

    ERIC Educational Resources Information Center

    Meng, Yu

    2012-01-01

    The kernel method of test equating is a unified approach to test equating with some advantages over traditional equating methods. Therefore, it is important to evaluate in a comprehensive way the usefulness and appropriateness of the Kernel equating (KE) method, as well as its advantages and disadvantages compared with several popular item…

  1. Comparison of Kernel Equating and Item Response Theory Equating Methods

    ERIC Educational Resources Information Center

    Meng, Yu

    2012-01-01

    The kernel method of test equating is a unified approach to test equating with some advantages over traditional equating methods. Therefore, it is important to evaluate in a comprehensive way the usefulness and appropriateness of the Kernel equating (KE) method, as well as its advantages and disadvantages compared with several popular item…

  2. The Statistical Drake Equation

    NASA Astrophysics Data System (ADS)

    Maccone, Claudio

    2010-12-01

    We provide the statistical generalization of the Drake equation. From a simple product of seven positive numbers, the Drake equation is now turned into the product of seven positive random variables. We call this "the Statistical Drake Equation". The mathematical consequences of this transformation are then derived. The proof of our results is based on the Central Limit Theorem (CLT) of Statistics. In loose terms, the CLT states that the sum of any number of independent random variables, each of which may be ARBITRARILY distributed, approaches a Gaussian (i.e. normal) random variable. This is called the Lyapunov Form of the CLT, or the Lindeberg Form of the CLT, depending on the mathematical constraints assumed on the third moments of the various probability distributions. In conclusion, we show that: The new random variable N, yielding the number of communicating civilizations in the Galaxy, follows the LOGNORMAL distribution. Then, as a consequence, the mean value of this lognormal distribution is the ordinary N in the Drake equation. The standard deviation, mode, and all the moments of this lognormal N are also found. The seven factors in the ordinary Drake equation now become seven positive random variables. The probability distribution of each random variable may be ARBITRARY. The CLT in the so-called Lyapunov or Lindeberg forms (that both do not assume the factors to be identically distributed) allows for that. In other words, the CLT "translates" into our statistical Drake equation by allowing an arbitrary probability distribution for each factor. This is both physically realistic and practically very useful, of course. An application of our statistical Drake equation then follows. The (average) DISTANCE between any two neighboring and communicating civilizations in the Galaxy may be shown to be inversely proportional to the cubic root of N. Then, in our approach, this distance becomes a new random variable. We derive the relevant probability density

  3. A Quadratic Spring Equation

    ERIC Educational Resources Information Center

    Fay, Temple H.

    2010-01-01

    Through numerical investigations, we study examples of the forced quadratic spring equation [image omitted]. By performing trial-and-error numerical experiments, we demonstrate the existence of stability boundaries in the phase plane indicating initial conditions yielding bounded solutions, investigate the resonance boundary in the [omega]…

  4. Structural Equation Model Trees

    ERIC Educational Resources Information Center

    Brandmaier, Andreas M.; von Oertzen, Timo; McArdle, John J.; Lindenberger, Ulman

    2013-01-01

    In the behavioral and social sciences, structural equation models (SEMs) have become widely accepted as a modeling tool for the relation between latent and observed variables. SEMs can be seen as a unification of several multivariate analysis techniques. SEM Trees combine the strengths of SEMs and the decision tree paradigm by building tree…

  5. Balancing Chemical Equations.

    ERIC Educational Resources Information Center

    Savoy, L. G.

    1988-01-01

    Describes a study of students' ability to balance equations. Answers to a test on this topic were analyzed to determine the level of understanding and processes used by the students. Presented is a method to teach this skill to high school chemistry students. (CW)

  6. Do Differential Equations Swing?

    ERIC Educational Resources Information Center

    Maruszewski, Richard F., Jr.

    2006-01-01

    One of the units of in a standard differential equations course is a discussion of the oscillatory motion of a spring and the associated material on forcing functions and resonance. During the presentation on practical resonance, the instructor may tell students that it is similar to when they take their siblings to the playground and help them on…

  7. Modelling by Differential Equations

    ERIC Educational Resources Information Center

    Chaachoua, Hamid; Saglam, Ayse

    2006-01-01

    This paper aims to show the close relation between physics and mathematics taking into account especially the theory of differential equations. By analysing the problems posed by scientists in the seventeenth century, we note that physics is very important for the emergence of this theory. Taking into account this analysis, we show the…

  8. Structural analysis equations

    Treesearch

    Lawrence A. Soltis

    1999-01-01

    Equations for deformation and stress, which are the basis for tension members and beam and column design, are discussed in this chapter. The first two sections cover tapered members, straight members, and special considerations such as notches, slits, and size effect. A third section presents stability criteria for members subject to buckling and for members subject to...

  9. Dunkl Hyperbolic Equations

    NASA Astrophysics Data System (ADS)

    Mejjaoli, Hatem

    2008-12-01

    We introduce and study the Dunkl symmetric systems. We prove the well-posedness results for the Cauchy problem for these systems. Eventually we describe the finite speed of it. Next the semi-linear Dunkl-wave equations are also studied.

  10. Modelling by Differential Equations

    ERIC Educational Resources Information Center

    Chaachoua, Hamid; Saglam, Ayse

    2006-01-01

    This paper aims to show the close relation between physics and mathematics taking into account especially the theory of differential equations. By analysing the problems posed by scientists in the seventeenth century, we note that physics is very important for the emergence of this theory. Taking into account this analysis, we show the…

  11. Structural Equation Model Trees

    ERIC Educational Resources Information Center

    Brandmaier, Andreas M.; von Oertzen, Timo; McArdle, John J.; Lindenberger, Ulman

    2013-01-01

    In the behavioral and social sciences, structural equation models (SEMs) have become widely accepted as a modeling tool for the relation between latent and observed variables. SEMs can be seen as a unification of several multivariate analysis techniques. SEM Trees combine the strengths of SEMs and the decision tree paradigm by building tree…

  12. Equating Practical Examinations.

    ERIC Educational Resources Information Center

    Lunz, Mary E.; And Others

    This paper describes and illustrates a method for equating examinations with multiple facets (i.e., items, examinees, judges, tasks, and rating scales). The data are from the practical section of two histotechnology certification examinations. The first practical examination involved 210 examinees, 14 judges, 15 slides, 3 tasks, and 2 rating…

  13. Structural analysis equations

    Treesearch

    Douglas R. Rammer

    2010-01-01

    Equations for deformation and stress, which are the basis for tension members and beam and column design, are discussed in this chapter. The first two sections cover tapered members, straight members, and special considerations such as notches, slits, and size effect. A third section presents stability criteria for members subject to buckling and for members subject to...

  14. Generalized reduced magnetohydrodynamic equations

    SciTech Connect

    Kruger, S.E.

    1999-02-01

    A new derivation of reduced magnetohydrodynamic (MHD) equations is presented. A multiple-time-scale expansion is employed. It has the advantage of clearly separating the three time scales of the problem associated with (1) MHD equilibrium, (2) fluctuations whose wave vector is aligned perpendicular to the magnetic field, and (3) those aligned parallel to the magnetic field. The derivation is carried out without relying on a large aspect ratio assumption; therefore this model can be applied to any general configuration. By accounting for the MHD equilibrium and constraints to eliminate the fast perpendicular waves, equations are derived to evolve scalar potential quantities on a time scale associated with the parallel wave vector (shear-Alfven wave time scale), which is the time scale of interest for MHD instability studies. Careful attention is given in the derivation to satisfy energy conservation and to have manifestly divergence-free magnetic fields to all orders in the expansion parameter. Additionally, neoclassical closures and equilibrium shear flow effects are easily accounted for in this model. Equations for the inner resistive layer are derived which reproduce the linear ideal and resistive stability criterion of Glasser, Greene, and Johnson. The equations have been programmed into a spectral initial value code and run with shear flow that is consistent with the equilibrium input into the code. Linear results of tearing modes with shear flow are presented which differentiate the effects of shear flow gradients in the layer with the effects of the shear flow decoupling multiple harmonics.

  15. Parallel Multigrid Equation Solver

    SciTech Connect

    Adams, Mark

    2001-09-07

    Prometheus is a fully parallel multigrid equation solver for matrices that arise in unstructured grid finite element applications. It includes a geometric and an algebraic multigrid method and has solved problems of up to 76 mullion degrees of feedom, problems in linear elasticity on the ASCI blue pacific and ASCI red machines.

  16. Quenching equation for scintillation

    NASA Astrophysics Data System (ADS)

    Kato, Takahisa

    1980-06-01

    A mathematical expression is postulated showing the relationship between counting rate and quenching agent concentration in a liquid scintillation solution. The expression is more suited to a wider range of quenching agent concentrations than the Stern-Volmer equation. An estimation of the quenched correction is demonstrated using the expression.

  17. Stochastic Hodgkin-Huxley equations with colored noise terms in the conductances.

    PubMed

    Güler, Marifi

    2013-01-01

    The excitability of cells is facilitated by voltage-gated ion channels. These channels accommodate a multiple number of gates individually. The possible impact of that gate multiplicity on the cell's function, specifically when the membrane area is of limited size, was investigated in the author's prior work (Güler, 2011 ). There, it was found that a nontrivially persistent correlation takes place between the transmembrane voltage fluctuations (also between the fluctuations in the gating variables) and the component of open channel fluctuations attributed to the gate multiplicity. This nontrivial phenomenon was found to be playing a major augmentative role for the elevation of excitability and spontaneous firing in small cells. In addition, the same phenomenon was found to be enhancing spike coherence significantly. Here we extend Fox and Lu's ( 1994 ) stochastic Hodgkin-Huxley equations by incorporating colored noise terms into the conductances there to obtain a formalism capable of capturing the addressed cross-correlations. Statistics of spike generation, spike coherence, firing efficiency, latency, and jitter from the articulated set of equations are found to be highly accurate in comparison with the corresponding statistics from the exact microscopic Markov simulations. This way, it is demonstrated vividly that our formulation overcomes the inherent inadequacy of the Fox and Lu equations. Finally, a recently proposed diffusion approximation method (Linaro, Storace, & Giugliano, 2011 ) is taken into consideration, and a discussion on its character is pursued.

  18. Body Fat Equations and Electrical Bioimpedance Values in Prediction of Cardiovascular Risk Factors in Eutrophic and Overweight Adolescents

    PubMed Central

    Faria, Franciane Rocha; Faria, Eliane Rodrigues; Cecon, Roberta Stofeles; Barbosa Júnior, Djalma Adão; Franceschini, Sylvia do Carmo Castro; Peluzio, Maria do Carmo Gouveia; Ribeiro, Andréia Queiroz; Lira, Pedro Israel Cabral; Cecon, Paulo Roberto; Priore, Silvia Eloiza

    2013-01-01

    The aim of this study was to analyze body fat anthropometric equations and electrical bioimpedance analysis (BIA) in the prediction of cardiovascular risk factors in eutrophic and overweight adolescents. 210 adolescents were divided into eutrophic group (G1) and overweight group (G2). The percentage of body fat (% BF) was estimated using 10 body fat anthropometric equations and 2 BIA. We measured lipid profiles, uric acid, insulin, fasting glucose, homeostasis model assessment-insulin resistance (HOMA-IR), and blood pressure. We found that 76.7% of the adolescents exhibited inadequacy of at least one biochemical parameter or clinical cardiovascular risk. Higher values of triglycerides (TG) (P = 0.001), insulin, and HOMA-IR (P < 0.001) were observed in the G2 adolescents. In multivariate linear regression analysis, the % BF from equation (5) was associated with TG, diastolic blood pressure, and insulin in G1. Among the G2 adolescents, the % BF estimated by (5) and (9) was associated with LDL, TG, insulin, and the HOMA-IR. Body fat anthropometric equations were associated with cardiovascular risk factors and should be used to assess the nutritional status of adolescents. In this study, equation (5) was associated with a higher number of cardiovascular risk factors independent of the nutritional status of adolescents. PMID:23762051

  19. Nonlinear equations of 'variable type'

    NASA Astrophysics Data System (ADS)

    Larkin, N. A.; Novikov, V. A.; Ianenko, N. N.

    In this monograph, new scientific results related to the theory of equations of 'variable type' are presented. Equations of 'variable type' are equations for which the original type is not preserved within the entire domain of coefficient definition. This part of the theory of differential equations with partial derivatives has been developed intensively in connection with the requirements of mechanics. The relations between equations of the considered type and the problems of mathematical physics are explored, taking into account quasi-linear equations, and models of mathematical physics which lead to equations of 'variable type'. Such models are related to transonic flows, problems involving a separation of the boundary layer, gasdynamics and the van der Waals equation, shock wave phenomena, and a combustion model with a turbulent diffusion flame. Attention is also given to nonlinear parabolic equations, and nonlinear partial differential equations of the third order.

  20. Methods for Equating Mental Tests.

    DTIC Science & Technology

    1984-11-01

    1983) compared conventional and IRT methods for equating the Test of English as a Foreign Language ( TOEFL ) after chaining. Three conventional and...three IRT equating methods were examined in this study; two sections of TOEFL were each (separately) equated. The IRT methods included the following: (a...group. A separate base form was established for each of the six equating methods. Instead of equating the base-form TOEFL to itself, the last (eighth

  1. Supersymmetric fifth order evolution equations

    SciTech Connect

    Tian, K.; Liu, Q. P.

    2010-03-08

    This paper considers supersymmetric fifth order evolution equations. Within the framework of symmetry approach, we give a list containing six equations, which are (potentially) integrable systems. Among these equations, the most interesting ones include a supersymmetric Sawada-Kotera equation and a novel supersymmetric fifth order KdV equation. For the latter, we supply some properties such as a Hamiltonian structures and a possible recursion operator.

  2. Brownian motion from Boltzmann's equation.

    NASA Technical Reports Server (NTRS)

    Montgomery, D.

    1971-01-01

    Two apparently disparate lines of inquiry in kinetic theory are shown to be equivalent: (1) Brownian motion as treated by the (stochastic) Langevin equation and Fokker-Planck equation; and (2) Boltzmann's equation. The method is to derive the kinetic equation for Brownian motion from the Boltzmann equation for a two-component neutral gas by a simultaneous expansion in the density and mass ratios.

  3. Flavored quantum Boltzmann equations

    SciTech Connect

    Cirigliano, Vincenzo; Lee, Christopher; Ramsey-Musolf, Michael J.; Tulin, Sean

    2010-05-15

    We derive from first principles, using nonequilibrium field theory, the quantum Boltzmann equations that describe the dynamics of flavor oscillations, collisions, and a time-dependent mass matrix in the early universe. Working to leading nontrivial order in ratios of relevant time scales, we study in detail a toy model for weak-scale baryogenesis: two scalar species that mix through a slowly varying time-dependent and CP-violating mass matrix, and interact with a thermal bath. This model clearly illustrates how the CP asymmetry arises through coherent flavor oscillations in a nontrivial background. We solve the Boltzmann equations numerically for the density matrices, investigating the impact of collisions in various regimes.

  4. Perturbed nonlinear differential equations

    NASA Technical Reports Server (NTRS)

    Proctor, T. G.

    1974-01-01

    For perturbed nonlinear systems, a norm, other than the supremum norm, is introduced on some spaces of continuous functions. This makes possible the study of new types of behavior. A study is presented on a perturbed nonlinear differential equation defined on a half line, and the existence of a family of solutions with special boundedness properties is established. The ideas developed are applied to the study of integral manifolds, and examples are given.

  5. Dirac equation for strings

    NASA Astrophysics Data System (ADS)

    Trzetrzelewski, Maciej

    2016-11-01

    Starting with a Nambu-Goto action, a Dirac-like equation can be constructed by taking the square-root of the momentum constraint. The eigenvalues of the resulting Hamiltonian are real and correspond to masses of the excited string. In particular there are no tachyons. A special case of radial oscillations of a closed string in Minkowski space-time admits exact solutions in terms of wave functions of the harmonic oscillator.

  6. Quantum molecular master equations

    NASA Astrophysics Data System (ADS)

    Brechet, Sylvain D.; Reuse, Francois A.; Maschke, Klaus; Ansermet, Jean-Philippe

    2016-10-01

    We present the quantum master equations for midsize molecules in the presence of an external magnetic field. The Hamiltonian describing the dynamics of a molecule accounts for the molecular deformation and orientation properties, as well as for the electronic properties. In order to establish the master equations governing the relaxation of free-standing molecules, we have to split the molecule into two weakly interacting parts, a bath and a bathed system. The adequate choice of these systems depends on the specific physical system under consideration. Here we consider a first system consisting of the molecular deformation and orientation properties and the electronic spin properties and a second system composed of the remaining electronic spatial properties. If the characteristic time scale associated with the second system is small with respect to that of the first, the second may be considered as a bath for the first. Assuming that both systems are weakly coupled and initially weakly correlated, we obtain the corresponding master equations. They describe notably the relaxation of magnetic properties of midsize molecules, where the change of the statistical properties of the electronic orbitals is expected to be slow with respect to the evolution time scale of the bathed system.

  7. Fractional Vorticity Equations

    NASA Astrophysics Data System (ADS)

    Schertzer, D.; Tchguirinskaia, I.; Lovejoy, S.; Tuck, A.

    2012-04-01

    As a result of a thorough discussion (Schertzer et al., Atmos. Chem. Phys., 12, 327-336, 2012 ) of the limitations of the quasi-geostrophic approximation and turbulence, fractional vorticity equations were obtained. This was done with the help of an anisotropic scaling analysis, instead of the classical scale analysis, as done to derive the quasi-geostrophic approximation. This breaks the rotational symmetry of the classical 3D vorticity equations and a priori yields a (2 + Hz)-dimensional turbulence (0 ≤ Hz ≤ 1). This corresponds to a first step in the derivation of a dynamical alternative to the quasi-geostrophic approximation and turbulence. The corresponding precise definition of fractional dimensional turbulence already demonstrates that the classical 2-D and 3-D turbulence are not the main options to understand atmospheric and oceanic dynamics. Although (2 + Hz)-dimensional turbulence (with 0 < Hz < 1) has more common features with 3-D turbulence than with 2-D turbulence, it has nevertheless very distinctive features: its scaling anisotropy is in agreement with the layered pancake structure, which is typical of rotating and stratified turbulence, but not of the classical 3-D turbulence. In this presentation, we further discuss the properties of this set of deterministic-like equations, especially how they can generate a statistical scaling anisotropy, as well as the relevance of the theoretical value Hz = 5/9.

  8. Equations of Motion

    NASA Astrophysics Data System (ADS)

    Scherer, Philipp O. J.

    We discuss several strategies for the time integration of first order initial value problems. The explicit Euler forward difference has low error order. The much more accurate symmetric difference quotient can be used as the corrector step in combination with an explicit Euler predictor step and is often used for the time integration of partial differential equations. Methods with higher error order can be obtained from a Taylor series expansion, like the Nordsieck and Gear predictor-corrector methods which have been often applied in molecular dynamics calculations. Runge-Kutta methods are very important for ordinary differential equations. They are robust and allow an adaptive control of the step size. Very accurate results can be obtained for ordinary differential equations with extrapolation methods like the famous Gragg-Bulirsch-Stör method. Multistep methods use information from several points. Best known are Adams-Bashforth-Moulton methods and Gear methods (also known as backward differentiation methods), which are especially useful for stiff problems. The class of Verlet methods has been developed for molecular dynamics calculations. These are symplectic and time reversible and conserve energy over long trajectories.

  9. Double-Plate Penetration Equations

    NASA Technical Reports Server (NTRS)

    Hayashida, K. B.; Robinson, J. H.

    2000-01-01

    This report compares seven double-plate penetration predictor equations for accuracy and effectiveness of a shield design. Three of the seven are the Johnson Space Center original, modified, and new Cour-Palais equations. The other four are the Nysmith, Lundeberg-Stern-Bristow, Burch, and Wilkinson equations. These equations, except the Wilkinson equation, were derived from test results, with the velocities ranging up to 8 km/sec. Spreadsheet software calculated the projectile diameters for various velocities for the different equations. The results were plotted on projectile diameter versus velocity graphs for the expected orbital debris impact velocities ranging from 2 to 15 km/sec. The new Cour-Palais double-plate penetration equation was compared to the modified Cour-Palais single-plate penetration equation. Then the predictions from each of the seven double-plate penetration equations were compared to each other for a chosen shield design. Finally, these results from the equations were compared with test results performed at the NASA Marshall Space Flight Center. Because the different equations predict a wide range of projectile diameters at any given velocity, it is very difficult to choose the "right" prediction equation for shield configurations other than those exactly used in the equations' development. Although developed for various materials, the penetration equations alone cannot be relied upon to accurately predict the effectiveness of a shield without using hypervelocity impact tests to verify the design.

  10. Computing generalized Langevin equations and generalized Fokker-Planck equations.

    PubMed

    Darve, Eric; Solomon, Jose; Kia, Amirali

    2009-07-07

    The Mori-Zwanzig formalism is an effective tool to derive differential equations describing the evolution of a small number of resolved variables. In this paper we present its application to the derivation of generalized Langevin equations and generalized non-Markovian Fokker-Planck equations. We show how long time scales rates and metastable basins can be extracted from these equations. Numerical algorithms are proposed to discretize these equations. An important aspect is the numerical solution of the orthogonal dynamics equation which is a partial differential equation in a high dimensional space. We propose efficient numerical methods to solve this orthogonal dynamics equation. In addition, we present a projection formalism of the Mori-Zwanzig type that is applicable to discrete maps. Numerical applications are presented from the field of Hamiltonian systems.

  11. Reduction operators of Burgers equation

    PubMed Central

    Pocheketa, Oleksandr A.; Popovych, Roman O.

    2013-01-01

    The solution of the problem on reduction operators and nonclassical reductions of the Burgers equation is systematically treated and completed. A new proof of the theorem on the special “no-go” case of regular reduction operators is presented, and the representation of the coefficients of operators in terms of solutions of the initial equation is constructed for this case. All possible nonclassical reductions of the Burgers equation to single ordinary differential equations are exhaustively described. Any Lie reduction of the Burgers equation proves to be equivalent via the Hopf–Cole transformation to a parameterized family of Lie reductions of the linear heat equation. PMID:23576819

  12. Reduction operators of Burgers equation.

    PubMed

    Pocheketa, Oleksandr A; Popovych, Roman O

    2013-02-01

    The solution of the problem on reduction operators and nonclassical reductions of the Burgers equation is systematically treated and completed. A new proof of the theorem on the special "no-go" case of regular reduction operators is presented, and the representation of the coefficients of operators in terms of solutions of the initial equation is constructed for this case. All possible nonclassical reductions of the Burgers equation to single ordinary differential equations are exhaustively described. Any Lie reduction of the Burgers equation proves to be equivalent via the Hopf-Cole transformation to a parameterized family of Lie reductions of the linear heat equation.

  13. Instructional Cost Analysis: History and Present Inadequacies.

    ERIC Educational Resources Information Center

    Humphrey, David A.

    The cost analysis of instruction is conducted according to principles of teaching and learning that have often become historically dated. Using today's costing systems prevents determination of whether cost effectiveness actually exists. The patterns of instruction in higher education and the systems employed for instructional cost analysis are…

  14. Evaluating Equating Results: Percent Relative Error for Chained Kernel Equating

    ERIC Educational Resources Information Center

    Jiang, Yanlin; von Davier, Alina A.; Chen, Haiwen

    2012-01-01

    This article presents a method for evaluating equating results. Within the kernel equating framework, the percent relative error (PRE) for chained equipercentile equating was computed under the nonequivalent groups with anchor test (NEAT) design. The method was applied to two data sets to obtain the PRE, which can be used to measure equating…

  15. Differential Equations Compatible with Boundary Rational qKZ Equation

    NASA Astrophysics Data System (ADS)

    Takeyama, Yoshihiro

    2011-10-01

    We give diffierential equations compatible with the rational qKZ equation with boundary reflection. The total system contains the trigonometric degeneration of the bispectral qKZ equation of type (Cěen, Cn) which in the case of type GLn was studied by van Meer and Stokman. We construct an integral formula for solutions to our compatible system in a special case.

  16. Evaluating Equating Results: Percent Relative Error for Chained Kernel Equating

    ERIC Educational Resources Information Center

    Jiang, Yanlin; von Davier, Alina A.; Chen, Haiwen

    2012-01-01

    This article presents a method for evaluating equating results. Within the kernel equating framework, the percent relative error (PRE) for chained equipercentile equating was computed under the nonequivalent groups with anchor test (NEAT) design. The method was applied to two data sets to obtain the PRE, which can be used to measure equating…

  17. Young's equation revisited.

    PubMed

    Makkonen, Lasse

    2016-04-06

    Young's construction for a contact angle at a three-phase intersection forms the basis of all fields of science that involve wetting and capillary action. We find compelling evidence from recent experimental results on the deformation of a soft solid at the contact line, and displacement of an elastic wire immersed in a liquid, that Young's equation can only be interpreted by surface energies, and not as a balance of surface tensions. It follows that the a priori variable in finding equilibrium is not the position of the contact line, but the contact angle. This finding provides the explanation for the pinning of a contact line.

  18. The Arrhenius equation revisited.

    PubMed

    Peleg, Micha; Normand, Mark D; Corradini, Maria G

    2012-01-01

    The Arrhenius equation has been widely used as a model of the temperature effect on the rate of chemical reactions and biological processes in foods. Since the model requires that the rate increase monotonically with temperature, its applicability to enzymatic reactions and microbial growth, which have optimal temperature, is obviously limited. This is also true for microbial inactivation and chemical reactions that only start at an elevated temperature, and for complex processes and reactions that do not follow fixed order kinetics, that is, where the isothermal rate constant, however defined, is a function of both temperature and time. The linearity of the Arrhenius plot, that is, Ln[k(T)] vs. 1/T where T is in °K has been traditionally considered evidence of the model's validity. Consequently, the slope of the plot has been used to calculate the reaction or processes' "energy of activation," usually without independent verification. Many experimental and simulated rate constant vs. temperature relationships that yield linear Arrhenius plots can also be described by the simpler exponential model Ln[k(T)/k(T(reference))] = c(T-T(reference)). The use of the exponential model or similar empirical alternative would eliminate the confusing temperature axis inversion, the unnecessary compression of the temperature scale, and the need for kinetic assumptions that are hard to affirm in food systems. It would also eliminate the reference to the Universal gas constant in systems where a "mole" cannot be clearly identified. Unless proven otherwise by independent experiments, one cannot dismiss the notion that the apparent linearity of the Arrhenius plot in many food systems is due to a mathematical property of the model's equation rather than to the existence of a temperature independent "energy of activation." If T+273.16°C in the Arrhenius model's equation is replaced by T+b, where the numerical value of the arbitrary constant b is substantially larger than T and T

  19. Perturbed nonlinear differential equations

    NASA Technical Reports Server (NTRS)

    Proctor, T. G.

    1972-01-01

    The existence of a solution defined for all t and possessing a type of boundedness property is established for the perturbed nonlinear system y = f(t,y) + F(t,y). The unperturbed system x = f(t,x) has a dichotomy in which some solutions exist and are well behaved as t increases to infinity, and some solution exists and are well behaved as t decreases to minus infinity. A similar study is made for a perturbed nonlinear differential equation defined on a half line, R+, and the existence of a family of solutions with special boundedness properties is established. The ideas are applied to integral manifolds.

  20. Problems, Perspectives, and Practical Issues in Equating.

    ERIC Educational Resources Information Center

    Weiss, David J., Ed.

    1987-01-01

    Issues concerning equating test scores are discussed in an introduction, four papers, and two commentaries. Equating methods research, sampling errors, linear equating, population differences, sources of equating errors, and a circular equating paradigm are considered. (SLD)

  1. Noncommutativity and the Friedmann Equations

    SciTech Connect

    Sabido, M.; Socorro, J.; Guzman, W.

    2010-07-12

    In this paper we study noncommutative scalar field cosmology, we find the noncommutative Friedmann equations as well as the noncommutative Klein-Gordon equation, interestingly the noncommutative contributions are only present up to second order in the noncommutitive parameter.

  2. Conservational PDF Equations of Turbulence

    NASA Technical Reports Server (NTRS)

    Shih, Tsan-Hsing; Liu, Nan-Suey

    2010-01-01

    Recently we have revisited the traditional probability density function (PDF) equations for the velocity and species in turbulent incompressible flows. They are all unclosed due to the appearance of various conditional means which are modeled empirically. However, we have observed that it is possible to establish a closed velocity PDF equation and a closed joint velocity and species PDF equation through conditions derived from the integral form of the Navier-Stokes equations. Although, in theory, the resulted PDF equations are neither general nor unique, they nevertheless lead to the exact transport equations for the first moment as well as all higher order moments. We refer these PDF equations as the conservational PDF equations. This observation is worth further exploration for its validity and CFD application

  3. Shock wave structure using nonlinear model Boltzmann equations

    NASA Technical Reports Server (NTRS)

    Segal, Ben Maurice

    1971-01-01

    The structure of a strong plane shock wave in a monatomic rarefied perfect gas is one of the simplest problems able to be posed in kinetic theory, and one of the hardest to solve. Its simplicity lies in the absence of solid boundaries, geometrical complications, or internal molecular energy. Its difficulty arises from the great departure of the gas from equilibrium within the shock, which invalidates many of the techniques used successfully elsewhere in kinetic theory. In addition to this theoretical challenge, the modern development of ballistics and hypersonic flight has helped to stimulate extensive theoretical and experimental interest in the shock problem. The experimenters in turn have encountered great difficulties on account of the very small physical dimensions of shocks. In fact, until very recently indeed, any close comparisons of theoretical and experimental shock structure results have been rather unprofitable due to the inadequacies of both theory and experiment. During the last few years this situation has been appreciably improved by development of the Monte Carlo method. This allows idealized 'experiments' to be performed on large computers instead of in wind tunnels, using a known intermolecular force law. The most developed of these methods has been shown to be equivalent theoretically to the Boltzmann equation and to give results which agree extremely closely with measurements of high accuracy. Thus Monte Carlo results not only form the soundest basis for our present theoretical knowledge of shock wave structure, but, for purposes of developing other theories, can also be considered a very valuable experimental resource. However, such results remain very expensive to obtain. In this thesis we develop more economical kinetic theory methods for the approximate prediction of shock structure, and compare our results with those of the Monte Carlo method.

  4. ``Riemann equations'' in bidifferential calculus

    NASA Astrophysics Data System (ADS)

    Chvartatskyi, O.; Müller-Hoissen, F.; Stoilov, N.

    2015-10-01

    We consider equations that formally resemble a matrix Riemann (or Hopf) equation in the framework of bidifferential calculus. With different choices of a first-order bidifferential calculus, we obtain a variety of equations, including a semi-discrete and a fully discrete version of the matrix Riemann equation. A corresponding universal solution-generating method then either yields a (continuous or discrete) Cole-Hopf transformation, or leaves us with the problem of solving Riemann equations (hence an application of the hodograph method). If the bidifferential calculus extends to second order, solutions of a system of "Riemann equations" are also solutions of an equation that arises, on the universal level of bidifferential calculus, as an integrability condition. Depending on the choice of bidifferential calculus, the latter can represent a number of prominent integrable equations, like self-dual Yang-Mills, as well as matrix versions of the two-dimensional Toda lattice, Hirota's bilinear difference equation, (2+1)-dimensional Nonlinear Schrödinger (NLS), Kadomtsev-Petviashvili (KP) equation, and Davey-Stewartson equations. For all of them, a recent (non-isospectral) binary Darboux transformation result in bidifferential calculus applies, which can be specialized to generate solutions of the associated "Riemann equations." For the latter, we clarify the relation between these specialized binary Darboux transformations and the aforementioned solution-generating method. From (arbitrary size) matrix versions of the "Riemann equations" associated with an integrable equation, possessing a bidifferential calculus formulation, multi-soliton-type solutions of the latter can be generated. This includes "breaking" multi-soliton-type solutions of the self-dual Yang-Mills and the (2+1)-dimensional NLS equation, which are parametrized by solutions of Riemann equations.

  5. The Forced Hard Spring Equation

    ERIC Educational Resources Information Center

    Fay, Temple H.

    2006-01-01

    Through numerical investigations, various examples of the Duffing type forced spring equation with epsilon positive, are studied. Since [epsilon] is positive, all solutions to the associated homogeneous equation are periodic and the same is true with the forcing applied. The damped equation exhibits steady state trajectories with the interesting…

  6. Successfully Transitioning to Linear Equations

    ERIC Educational Resources Information Center

    Colton, Connie; Smith, Wendy M.

    2014-01-01

    The Common Core State Standards for Mathematics (CCSSI 2010) asks students in as early as fourth grade to solve word problems using equations with variables. Equations studied at this level generate a single solution, such as the equation x + 10 = 25. For students in fifth grade, the Common Core standard for algebraic thinking expects them to…

  7. Solving Nonlinear Coupled Differential Equations

    NASA Technical Reports Server (NTRS)

    Mitchell, L.; David, J.

    1986-01-01

    Harmonic balance method developed to obtain approximate steady-state solutions for nonlinear coupled ordinary differential equations. Method usable with transfer matrices commonly used to analyze shaft systems. Solution to nonlinear equation, with periodic forcing function represented as sum of series similar to Fourier series but with form of terms suggested by equation itself.

  8. Successfully Transitioning to Linear Equations

    ERIC Educational Resources Information Center

    Colton, Connie; Smith, Wendy M.

    2014-01-01

    The Common Core State Standards for Mathematics (CCSSI 2010) asks students in as early as fourth grade to solve word problems using equations with variables. Equations studied at this level generate a single solution, such as the equation x + 10 = 25. For students in fifth grade, the Common Core standard for algebraic thinking expects them to…

  9. Generalized Klein-Kramers equations.

    PubMed

    Fa, Kwok Sau

    2012-12-21

    A generalized Klein-Kramers equation for a particle interacting with an external field is proposed. The equation generalizes the fractional Klein-Kramers equation introduced by Barkai and Silbey [J. Phys. Chem. B 104, 3866 (2000)]. Besides, the generalized Klein-Kramers equation can also recover the integro-differential Klein-Kramers equation for continuous-time random walk; this means that it can describe the subdiffusive and superdiffusive regimes in the long-time limit. Moreover, analytic solutions for first two moments both in velocity and displacement (for force-free case) are obtained, and their dynamic behaviors are investigated.

  10. Impact of Matched Samples Equating Methods on Equating Accuracy and the Adequacy of Equating Assumptions

    ERIC Educational Resources Information Center

    Powers, Sonya Jean

    2010-01-01

    When test forms are administered to examinee groups that differ in proficiency, equating procedures are used to disentangle group differences from form differences. This dissertation investigates the extent to which equating results are population invariant, the impact of group differences on equating results, the impact of group differences on…

  11. On nonautonomous Dirac equation

    SciTech Connect

    Hovhannisyan, Gro; Liu Wen

    2009-12-15

    We construct the fundamental solution of time dependent linear ordinary Dirac system in terms of unknown phase functions. This construction gives approximate representation of solutions which is useful for the study of asymptotic behavior. Introducing analog of Rayleigh quotient for differential equations we generalize Hartman-Wintner asymptotic integration theorems with the error estimates for applications to the Dirac system. We also introduce the adiabatic invariants for the Dirac system, which are similar to the adiabatic invariant of Lorentz's pendulum. Using a small parameter method it is shown that the change in the adiabatic invariants approaches zero with the power speed as a small parameter approaches zero. As another application we calculate the transition probabilities for the Dirac system. We show that for the special choice of electromagnetic field, the only transition of an electron to the positron with the opposite spin orientation is possible.

  12. Λ scattering equations

    NASA Astrophysics Data System (ADS)

    Gomez, Humberto

    2016-06-01

    The CHY representation of scattering amplitudes is based on integrals over the moduli space of a punctured sphere. We replace the punctured sphere by a double-cover version. The resulting scattering equations depend on a parameter Λ controlling the opening of a branch cut. The new representation of scattering amplitudes possesses an enhanced redundancy which can be used to fix, modulo branches, the location of four punctures while promoting Λ to a variable. Via residue theorems we show how CHY formulas break up into sums of products of smaller (off-shell) ones times a propagator. This leads to a powerful way of evaluating CHY integrals of generic rational functions, which we call the Λ algorithm.

  13. Elliptic scattering equations

    NASA Astrophysics Data System (ADS)

    Cardona, Carlos; Gomez, Humberto

    2016-06-01

    Recently the CHY approach has been extended to one loop level using elliptic functions and modular forms over a Jacobian variety. Due to the difficulty in manipulating these kind of functions, we propose an alternative prescription that is totally algebraic. This new proposal is based on an elliptic algebraic curve embedded in a mathbb{C}{P}^2 space. We show that for the simplest integrand, namely the n - gon, our proposal indeed reproduces the expected result. By using the recently formulated Λ-algorithm, we found a novel recurrence relation expansion in terms of tree level off-shell amplitudes. Our results connect nicely with recent results on the one-loop formulation of the scattering equations. In addition, this new proposal can be easily stretched out to hyperelliptic curves in order to compute higher genus.

  14. The classical Bloch equations

    NASA Astrophysics Data System (ADS)

    Frimmer, Martin; Novotny, Lukas

    2014-10-01

    Coherent control of a quantum mechanical two-level system is at the heart of magnetic resonance imaging, quantum information processing, and quantum optics. Among the most prominent phenomena in quantum coherent control are Rabi oscillations, Ramsey fringes, and Hahn echoes. We demonstrate that these phenomena can be derived classically by use of a simple coupled-harmonic-oscillator model. The classical problem can be cast in a form that is formally equivalent to the quantum mechanical Bloch equations with the exception that the longitudinal and the transverse relaxation times (T1 and T2) are equal. The classical analysis is intuitive and well suited for familiarizing students with the basic concepts of quantum coherent control, while at the same time highlighting the fundamental differences between classical and quantum theories.

  15. Structural Equation Model Trees

    PubMed Central

    Brandmaier, Andreas M.; von Oertzen, Timo; McArdle, John J.; Lindenberger, Ulman

    2015-01-01

    In the behavioral and social sciences, structural equation models (SEMs) have become widely accepted as a modeling tool for the relation between latent and observed variables. SEMs can be seen as a unification of several multivariate analysis techniques. SEM Trees combine the strengths of SEMs and the decision tree paradigm by building tree structures that separate a data set recursively into subsets with significantly different parameter estimates in a SEM. SEM Trees provide means for finding covariates and covariate interactions that predict differences in structural parameters in observed as well as in latent space and facilitate theory-guided exploration of empirical data. We describe the methodology, discuss theoretical and practical implications, and demonstrate applications to a factor model and a linear growth curve model. PMID:22984789

  16. Solitary Wave Solutions of KP equation, Cylindrical KP Equation and Spherical KP Equation

    NASA Astrophysics Data System (ADS)

    Li, Xiang-Zheng; Zhang, Jin-Liang; Wang, Ming-Liang

    2017-02-01

    Three (2+1)-dimensional equations–KP equation, cylindrical KP equation and spherical KP equation, have been reduced to the same KdV equation by different transformation of variables respectively. Since the single solitary wave solution and 2-solitary wave solution of the KdV equation have been known already, substituting the solutions of the KdV equation into the corresponding transformation of variables respectively, the single and 2-solitary wave solutions of the three (2+1)-dimensional equations can be obtained successfully. Supported by the National Natural Science Foundation of China under Grant No. 11301153 and the Doctoral Foundation of Henan University of Science and Technology under Grant No. 09001562, and the Science and Technology Innovation Platform of Henan University of Science and Technology under Grant No. 2015XPT001

  17. Mode decomposition evolution equations

    PubMed Central

    Wang, Yang; Wei, Guo-Wei; Yang, Siyang

    2011-01-01

    Partial differential equation (PDE) based methods have become some of the most powerful tools for exploring the fundamental problems in signal processing, image processing, computer vision, machine vision and artificial intelligence in the past two decades. The advantages of PDE based approaches are that they can be made fully automatic, robust for the analysis of images, videos and high dimensional data. A fundamental question is whether one can use PDEs to perform all the basic tasks in the image processing. If one can devise PDEs to perform full-scale mode decomposition for signals and images, the modes thus generated would be very useful for secondary processing to meet the needs in various types of signal and image processing. Despite of great progress in PDE based image analysis in the past two decades, the basic roles of PDEs in image/signal analysis are only limited to PDE based low-pass filters, and their applications to noise removal, edge detection, segmentation, etc. At present, it is not clear how to construct PDE based methods for full-scale mode decomposition. The above-mentioned limitation of most current PDE based image/signal processing methods is addressed in the proposed work, in which we introduce a family of mode decomposition evolution equations (MoDEEs) for a vast variety of applications. The MoDEEs are constructed as an extension of a PDE based high-pass filter (Europhys. Lett., 59(6): 814, 2002) by using arbitrarily high order PDE based low-pass filters introduced by Wei (IEEE Signal Process. Lett., 6(7): 165, 1999). The use of arbitrarily high order PDEs is essential to the frequency localization in the mode decomposition. Similar to the wavelet transform, the present MoDEEs have a controllable time-frequency localization and allow a perfect reconstruction of the original function. Therefore, the MoDEE operation is also called a PDE transform. However, modes generated from the present approach are in the spatial or time domain and can be

  18. Mode decomposition evolution equations.

    PubMed

    Wang, Yang; Wei, Guo-Wei; Yang, Siyang

    2012-03-01

    Partial differential equation (PDE) based methods have become some of the most powerful tools for exploring the fundamental problems in signal processing, image processing, computer vision, machine vision and artificial intelligence in the past two decades. The advantages of PDE based approaches are that they can be made fully automatic, robust for the analysis of images, videos and high dimensional data. A fundamental question is whether one can use PDEs to perform all the basic tasks in the image processing. If one can devise PDEs to perform full-scale mode decomposition for signals and images, the modes thus generated would be very useful for secondary processing to meet the needs in various types of signal and image processing. Despite of great progress in PDE based image analysis in the past two decades, the basic roles of PDEs in image/signal analysis are only limited to PDE based low-pass filters, and their applications to noise removal, edge detection, segmentation, etc. At present, it is not clear how to construct PDE based methods for full-scale mode decomposition. The above-mentioned limitation of most current PDE based image/signal processing methods is addressed in the proposed work, in which we introduce a family of mode decomposition evolution equations (MoDEEs) for a vast variety of applications. The MoDEEs are constructed as an extension of a PDE based high-pass filter (Europhys. Lett., 59(6): 814, 2002) by using arbitrarily high order PDE based low-pass filters introduced by Wei (IEEE Signal Process. Lett., 6(7): 165, 1999). The use of arbitrarily high order PDEs is essential to the frequency localization in the mode decomposition. Similar to the wavelet transform, the present MoDEEs have a controllable time-frequency localization and allow a perfect reconstruction of the original function. Therefore, the MoDEE operation is also called a PDE transform. However, modes generated from the present approach are in the spatial or time domain and can be

  19. Coagulation equations with gelation

    SciTech Connect

    Hendriks, E.M.; Ernst, M.H.; Ziff, R.M.

    1983-06-01

    Smoluchowski's equation for rapid coagulation is used to describe the kinetics of gelation, in which the coagulation kernel K/sub i/j models the bonding mechanism. For different classes of kernels we derive criteria for the occurrences of gelation, and obtain critical exponents in the pre- and postgelation stage in terms of the model parameters; we calculate bounds on the time of gelation t/sub c/, and give an exact postgelation solution for the model K/sub i/j = (ij)/sup ..omega../ (..omega..>1/2) and K/sub i/j = ..cap alpha../sup i/+j (..cap alpha..>1). For the model K/sub i/j = i/sup ..omega../+j/sup ..omega../ (..omega..<1, without gelation) initial solutions are given. It is argued that the kernel K/sub i/japprox. (ij)/sup ..omega../ with ..omega..approx. =1-1/d (d is dimensionality) effectively models the sol-gel transformation is polymerizing systems and approximately accounts for the effects of cross-linking and steric hindrance neglected in the classical theory of Flory and Stockmayer (..omega.. = 1). For all ..omega.. the exponents, tau = ..omega..+3/2 and sigma = ..omega..-1/2, ..gamma.. = (3/2-..omega..)/(..omega..-1/2) and ..beta.. = 1, characterize the size distribution, at the slightly below the gel point, under the assumption that scaling is valid.

  20. And now... Equations!

    NASA Astrophysics Data System (ADS)

    Sivron, Ran

    2006-12-01

    With the introduction of "Ranking Tests" some quantitative ideas were added to a large body of successful techniques for teaching conceptual astronomy. We incorporated those methods into our classes, and added a new ingredient: On a biweekly basis we included a quantitative excercise: Students working in groups of 2-3 draw geometrical figures, say: a circle, and use some trivial geometry equations, such as circumference = 2 x pi x r, in solving astronomy problems on 3'x4' white boards. A few examples included: Finding the distance to the moon with the Aristarchus method, finding the Solar Constant with the inverse square law, etc. Our methodolgy was similar to problem solving techniques in introductory physics. We were therefore worried that the students may be intimidated. To our surprize, not only did most students succeed in solving the problems, but they were not intimidated at all (that is: after the first class...) As a matter of fact, their test results improved, and the students interviewed expressed great enthusiasm for the new method. Warning: Our classes were relatively small <40 studets). For larger classes TA help is needed.

  1. JWL Equation of State

    SciTech Connect

    Menikoff, Ralph

    2015-12-15

    The JWL equation of state (EOS) is frequently used for the products (and sometimes reactants) of a high explosive (HE). Here we review and systematically derive important properties. The JWL EOS is of the Mie-Grueneisen form with a constant Grueneisen coefficient and a constants specific heat. It is thermodynamically consistent to specify the temperature at a reference state. However, increasing the reference state temperature restricts the EOS domain in the (V, e)-plane of phase space. The restrictions are due to the conditions that P ≥ 0, T ≥ 0, and the isothermal bulk modulus is positive. Typically, this limits the low temperature regime in expansion. The domain restrictions can result in the P-T equilibrium EOS of a partly burned HE failing to have a solution in some cases. For application to HE, the heat of detonation is discussed. Example JWL parameters for an HE, both products and reactions, are used to illustrate the restrictions on the domain of the EOS.

  2. A note on "Kepler's equation".

    NASA Astrophysics Data System (ADS)

    Dutka, J.

    1997-07-01

    This note briefly points out the formal similarity between Kepler's equation and equations developed in Hindu and Islamic astronomy for describing the lunar parallax. Specifically, an iterative method for calculating the lunar parallax has been developed by the astronomer Habash al-Hasib al-Marwazi (about 850 A.D., Turkestan), which is surprisingly similar to the iterative method for solving Kepler's equation invented by Leonhard Euler (1707 - 1783).

  3. Electronic representation of wave equation

    NASA Astrophysics Data System (ADS)

    Veigend, Petr; Kunovský, Jiří; Kocina, Filip; Nečasová, Gabriela; Šátek, Václav; Valenta, Václav

    2016-06-01

    The Taylor series method for solving differential equations represents a non-traditional way of a numerical solution. Even though this method is not much preferred in the literature, experimental calculations done at the Department of Intelligent Systems of the Faculty of Information Technology of TU Brno have verified that the accuracy and stability of the Taylor series method exceeds the currently used algorithms for numerically solving differential equations. This paper deals with solution of Telegraph equation using modelling of a series small pieces of the wire. Corresponding differential equations are solved by the Modern Taylor Series Method.

  4. Sedeonic equations of ideal fluid

    NASA Astrophysics Data System (ADS)

    Mironov, Victor L.; Mironov, Sergey V.

    2017-08-01

    In the present paper, we propose the generalized equations for an ideal fluid based on space-time algebra of sixteen-component sedeons. It is shown that the dynamics of isentropic fluid can be described by sedeonic first-order wave equation for fluid potentials. The key features of the proposed formalism are illustrated on the problem of the sound waves propagation. We consider the plane wave solution of linearized sedeonic wave equation and derive the second-order relations for the sound potential analogues to the Poynting theorem in electrodynamics. The generalization of proposed sedeonic equations for the description of viscous fluid is also discussed.

  5. Electronic representation of wave equation

    SciTech Connect

    Veigend, Petr; Kunovský, Jiří Kocina, Filip; Nečasová, Gabriela; Valenta, Václav; Šátek, Václav

    2016-06-08

    The Taylor series method for solving differential equations represents a non-traditional way of a numerical solution. Even though this method is not much preferred in the literature, experimental calculations done at the Department of Intelligent Systems of the Faculty of Information Technology of TU Brno have verified that the accuracy and stability of the Taylor series method exceeds the currently used algorithms for numerically solving differential equations. This paper deals with solution of Telegraph equation using modelling of a series small pieces of the wire. Corresponding differential equations are solved by the Modern Taylor Series Method.

  6. A Circuit Equation as a Limit of Eddy Current Equations

    NASA Astrophysics Data System (ADS)

    Amirat, Youcef; Touzani, Rachid

    2017-06-01

    We consider a three-dimensional time-harmonic eddy current problem formulated in terms of the magnetic field. We prove that in the case of one thin toroidal conductor, eddy current equations have as a limit Kirchhoff's algebraic equation for circuits. This approximation is valid in the case of small resistivity and voltage.

  7. A Circuit Equation as a Limit of Eddy Current Equations

    NASA Astrophysics Data System (ADS)

    Amirat, Youcef; Touzani, Rachid

    2017-10-01

    We consider a three-dimensional time-harmonic eddy current problem formulated in terms of the magnetic field. We prove that in the case of one thin toroidal conductor, eddy current equations have as a limit Kirchhoff's algebraic equation for circuits. This approximation is valid in the case of small resistivity and voltage.

  8. Coal from the equator

    SciTech Connect

    Darling, P.

    1995-10-01

    In the mid-1970s PT Rio Tinto Indonesia, a wholly owned subsidiary of CRA of Australia, entered into an agreement with BP of the United Kingdom to explore jointly for coal in Indonesia on a 50:50 basis. In 1978, the government of Indonesia invited tenders from foreign companies for the exploration and development of coal resources in eastern and southern Kalimantan (Borneo). The CRA-BP joint venture was successful in bidding for an area of 7,900 km{sup 2} in two blocks extending 300 km along the coast of eastern Kalimantan. In April 1982, PT Kaltim Prima Coal (KPC) entered into an agreement with the Indonesian State Coal Company whereby it could explore, produce, and market coal from the agreed blocks for a period of 30 years. From 1982 to 1986, detailed exploration led to the delineation of several propsects of which the most promising was near the small town of Sangatta, 200 km north of Balikpapan and less than one degree north of the equator. After this exploration period KPC relinquished all but 1,962 km{sup 2} of the original agreement area. In its simplest form, the mining operation can be described as: a series of open pits, coal preparation facilities, 13.7 km of overland conveyor to the coast, and a marine terminal capable of handling bulk carriers of up to 200K dwt. The remote location necessities a fully supportive infrastructure, including a power station, housing, schools, hospitals, water supply, and recreational facilities. In 1994 the mine produced 10M mt coal of which 70% was Prima coal, one of the highest quality internationally traded thermal coals.

  9. Graphical Solution of Polynomial Equations

    ERIC Educational Resources Information Center

    Grishin, Anatole

    2009-01-01

    Graphing utilities, such as the ubiquitous graphing calculator, are often used in finding the approximate real roots of polynomial equations. In this paper the author offers a simple graphing technique that allows one to find all solutions of a polynomial equation (1) of arbitrary degree; (2) with real or complex coefficients; and (3) possessing…

  10. Homotopy Solutions of Kepler's Equations

    NASA Technical Reports Server (NTRS)

    Fitz-Coy, Norman; Jang, Jiann-Woei

    1996-01-01

    Kepler's Equation is solved using an integrative algorithm developed using homotropy theory. The solution approach is applicable to both elliptic and hyperbolic forms of Kepler's Equation. The results from the proposed algorithm compare quite favorably with those from existing iterative schemes.

  11. Students' Understanding of Quadratic Equations

    ERIC Educational Resources Information Center

    López, Jonathan; Robles, Izraim; Martínez-Planell, Rafael

    2016-01-01

    Action-Process-Object-Schema theory (APOS) was applied to study student understanding of quadratic equations in one variable. This required proposing a detailed conjecture (called a genetic decomposition) of mental constructions students may do to understand quadratic equations. The genetic decomposition which was proposed can contribute to help…

  12. How Students Understand Physics Equations.

    ERIC Educational Resources Information Center

    Sherin, Bruce L.

    2001-01-01

    Analyzed a corpus of videotapes in which university students solved physics problems to determine how students learn to understand a physics equation. Found that students learn to understand physics equations in terms of a vocabulary of elements called symbolic forms, each associating a simple conceptual schema with a pattern of symbols. Findings…

  13. Uncertainty of empirical correlation equations

    NASA Astrophysics Data System (ADS)

    Feistel, R.; Lovell-Smith, J. W.; Saunders, P.; Seitz, S.

    2016-08-01

    The International Association for the Properties of Water and Steam (IAPWS) has published a set of empirical reference equations of state, forming the basis of the 2010 Thermodynamic Equation of Seawater (TEOS-10), from which all thermodynamic properties of seawater, ice, and humid air can be derived in a thermodynamically consistent manner. For each of the equations of state, the parameters have been found by simultaneously fitting equations for a range of different derived quantities using large sets of measurements of these quantities. In some cases, uncertainties in these fitted equations have been assigned based on the uncertainties of the measurement results. However, because uncertainties in the parameter values have not been determined, it is not possible to estimate the uncertainty in many of the useful quantities that can be calculated using the parameters. In this paper we demonstrate how the method of generalised least squares (GLS), in which the covariance of the input data is propagated into the values calculated by the fitted equation, and in particular into the covariance matrix of the fitted parameters, can be applied to one of the TEOS-10 equations of state, namely IAPWS-95 for fluid pure water. Using the calculated parameter covariance matrix, we provide some preliminary estimates of the uncertainties in derived quantities, namely the second and third virial coefficients for water. We recommend further investigation of the GLS method for use as a standard method for calculating and propagating the uncertainties of values computed from empirical equations.

  14. Drug Levels and Difference Equations

    ERIC Educational Resources Information Center

    Acker, Kathleen A.

    2004-01-01

    American university offers a course in finite mathematics whose focus is difference equation with emphasis on real world applications. The conclusion states that students learned to look for growth and decay patterns in raw data, to recognize both arithmetic and geometric growth, and to model both scenarios with graphs and difference equations.

  15. Equation of State of Solids.

    DTIC Science & Technology

    The report describes a program for computing equation of state parameters for a material which undergoes a phase transition, either rate-dependent or...obtaining explicit temperature dependence if measurements are made at three temperatures. It is applied to data from calcite. Finally a theoretical equation of state is described for solid iron. (Author)

  16. Complete solution of Boolean equations

    NASA Technical Reports Server (NTRS)

    Tapia, M. A.; Tucker, J. H.

    1980-01-01

    A method is presented for generating a single formula involving arbitary Boolean parameters, which includes in it each and every possible solution of a system of Boolean equations. An alternate condition equivalent to a known necessary and sufficient condition for solving a system of Boolean equations is given.

  17. Students' Understanding of Quadratic Equations

    ERIC Educational Resources Information Center

    López, Jonathan; Robles, Izraim; Martínez-Planell, Rafael

    2016-01-01

    Action-Process-Object-Schema theory (APOS) was applied to study student understanding of quadratic equations in one variable. This required proposing a detailed conjecture (called a genetic decomposition) of mental constructions students may do to understand quadratic equations. The genetic decomposition which was proposed can contribute to help…

  18. Generalized Multilevel Structural Equation Modeling

    ERIC Educational Resources Information Center

    Rabe-Hesketh, Sophia; Skrondal, Anders; Pickles, Andrew

    2004-01-01

    A unifying framework for generalized multilevel structural equation modeling is introduced. The models in the framework, called generalized linear latent and mixed models (GLLAMM), combine features of generalized linear mixed models (GLMM) and structural equation models (SEM) and consist of a response model and a structural model for the latent…

  19. The Bessel Equation and Dissipation

    NASA Astrophysics Data System (ADS)

    Alfinito, Eleonora; Vitiello, Giuseppe

    The Bessel equation can be cast, by means of suitable transformations, into a system of two damped/amplified parametric oscillator equations. The role of group contraction and the breakdown of loop-antiloop symmetry is discussed. The relation between the Virasoro algebra and the Euclidean algebras e(2) and e(3) is also presented.

  20. The Equations of Oceanic Motions

    NASA Astrophysics Data System (ADS)

    Müller, Peter

    2006-10-01

    Modeling and prediction of oceanographic phenomena and climate is based on the integration of dynamic equations. The Equations of Oceanic Motions derives and systematically classifies the most common dynamic equations used in physical oceanography, from large scale thermohaline circulations to those governing small scale motions and turbulence. After establishing the basic dynamical equations that describe all oceanic motions, M|ller then derives approximate equations, emphasizing the assumptions made and physical processes eliminated. He distinguishes between geometric, thermodynamic and dynamic approximations and between the acoustic, gravity, vortical and temperature-salinity modes of motion. Basic concepts and formulae of equilibrium thermodynamics, vector and tensor calculus, curvilinear coordinate systems, and the kinematics of fluid motion and wave propagation are covered in appendices. Providing the basic theoretical background for graduate students and researchers of physical oceanography and climate science, this book will serve as both a comprehensive text and an essential reference.

  1. Upper bounds for parabolic equations and the Landau equation

    NASA Astrophysics Data System (ADS)

    Silvestre, Luis

    2017-02-01

    We consider a parabolic equation in nondivergence form, defined in the full space [ 0 , ∞) ×Rd, with a power nonlinearity as the right-hand side. We obtain an upper bound for the solution in terms of a weighted control in Lp. This upper bound is applied to the homogeneous Landau equation with moderately soft potentials. We obtain an estimate in L∞ (Rd) for the solution of the Landau equation, for positive time, which depends only on the mass, energy and entropy of the initial data.

  2. Equating TIMSS Mathematics Subtests with Nonlinear Equating Methods Using NEAT Design: Circle-Arc Equating Approaches

    ERIC Educational Resources Information Center

    Ozdemir, Burhanettin

    2017-01-01

    The purpose of this study is to equate Trends in International Mathematics and Science Study (TIMSS) mathematics subtest scores obtained from TIMSS 2011 to scores obtained from TIMSS 2007 form with different nonlinear observed score equating methods under Non-Equivalent Anchor Test (NEAT) design where common items are used to link two or more test…

  3. Higher derivative gravity: Field equation as the equation of state

    NASA Astrophysics Data System (ADS)

    Dey, Ramit; Liberati, Stefano; Mohd, Arif

    2016-08-01

    One of the striking features of general relativity is that the Einstein equation is implied by the Clausius relation imposed on a small patch of locally constructed causal horizon. The extension of this thermodynamic derivation of the field equation to more general theories of gravity has been attempted many times in the last two decades. In particular, equations of motion for minimally coupled higher-curvature theories of gravity, but without the derivatives of curvature, have previously been derived using a thermodynamic reasoning. In that derivation the horizon slices were endowed with an entropy density whose form resembles that of the Noether charge for diffeomorphisms, and was dubbed the Noetheresque entropy. In this paper, we propose a new entropy density, closely related to the Noetheresque form, such that the field equation of any diffeomorphism-invariant metric theory of gravity can be derived by imposing the Clausius relation on a small patch of local causal horizon.

  4. On the Shallow Water Equations

    NASA Astrophysics Data System (ADS)

    Abdelrahman, Mahmoud A. E.

    2017-08-01

    We studied the shallow water equations of nonlinear conservation laws. First we studied the parametrisation of nonlinear elementary waves and hence we present the solution to the Riemann problem. We also prove the uniqueness of the Riemann solution. The Riemann invariants are formulated. Moreover we give an interesting application of the Riemann invariants. We present the shallow water system in a diagonal form, which admits the existence of a global smooth solution for these equations. The other application is to introduce new conservation laws for the shallow water equations.

  5. Langevin equations from time series.

    PubMed

    Racca, E; Porporato, A

    2005-02-01

    We discuss the link between the approach to obtain the drift and diffusion of one-dimensional Langevin equations from time series, and Pope and Ching's relationship for stationary signals. The two approaches are based on different interpretations of conditional averages of the time derivatives of the time series at given levels. The analysis provides a useful indication for the correct application of Pope and Ching's relationship to obtain stochastic differential equations from time series and shows its validity, in a generalized sense, for nondifferentiable processes originating from Langevin equations.

  6. The thermal-vortex equations

    NASA Technical Reports Server (NTRS)

    Shebalin, John V.

    1987-01-01

    The Boussinesq approximation is extended so as to explicitly account for the transfer of fluid energy through viscous action into thermal energy. Ideal and dissipative integral invariants are discussed, in addition to the general equations for thermal-fluid motion.

  7. Parametric Equations, Maple, and Tubeplots.

    ERIC Educational Resources Information Center

    Feicht, Louis

    1997-01-01

    Presents an activity that establishes a graphical foundation for parametric equations by using a graphing output form called tubeplots from the computer program Maple. Provides a comprehensive review and exploration of many previously learned topics. (ASK)

  8. On systems of Boolean equations

    NASA Astrophysics Data System (ADS)

    Leont'ev, V. K.; Tonoyan, G. P.

    2013-05-01

    Systems of Boolean equations are considered. The order of maximal consistent subsystems is estimated in the general and "typical" (in a probability sense) cases. Applications for several well-known discrete problems are given.

  9. Accuracy of perturbative master equations.

    PubMed

    Fleming, C H; Cummings, N I

    2011-03-01

    We consider open quantum systems with dynamics described by master equations that have perturbative expansions in the system-environment interaction. We show that, contrary to intuition, full-time solutions of order-2n accuracy require an order-(2n+2) master equation. We give two examples of such inaccuracies in the solutions to an order-2n master equation: order-2n inaccuracies in the steady state of the system and order-2n positivity violations. We show how these arise in a specific example for which exact solutions are available. This result has a wide-ranging impact on the validity of coupling (or friction) sensitive results derived from second-order convolutionless, Nakajima-Zwanzig, Redfield, and Born-Markov master equations.

  10. Comment on "Quantum Raychaudhuri equation"

    NASA Astrophysics Data System (ADS)

    Lashin, E. I.; Dou, Djamel

    2017-03-01

    We address the validity of the formalism and results presented in S. Das, Phys. Rev. D 89, 084068 (2014), 10.1103/PhysRevD.89.084068 with regard to the quantum Raychaudhuri equation. The author obtained the so-called quantum Raychaudhuri equation by replacing classical geodesics with quantal trajectories arising from Bhommian mechanics. The resulting modified equation was used to draw some conclusions about the inevitability of focusing and the formation of conjugate points and therefore singularity. We show that the whole procedure is full of problematic points, on both physical relevancy and mathematical correctness. In particular, we illustrate the problems associated with the technical derivation of the so-called quantum Raychaudhuri equation, as well as its invalid physical implications.

  11. Fractional Differential Equations and Multifractality

    NASA Astrophysics Data System (ADS)

    Larcheveque, M.; Schertzer, D. J.; Schertzer, D. J.; Duan, J.; Lovejoy, S.

    2001-12-01

    There has been a mushrooming interest in the linear Fokker-Planck Equation (FPPE) which corresponds to the generating equation of Lévy's anomalous diffusion. We already pointed out some theoretical and empirical limitations of the linear FPPE for various geophysical problems: the medium is in fact considered as homogeneous and the exponent of the power law of the pdf tails should be smaller than 2. We showed that a nonlinear extension based on a nonlinear Langevin equation forced by a Lévy stable motion overcomes these limitations. We show that in order to generate multifractal diffusion, and more generally multifractal fields, we need to furthermore consider fractional time derivatives in the Langevin equation and in FPPE. We compare our approach with the Continuous-Time Random Walk (CTWR) approach.

  12. Taxis equations for amoeboid cells.

    PubMed

    Erban, Radek; Othmer, Hans G

    2007-06-01

    The classical macroscopic chemotaxis equations have previously been derived from an individual-based description of the tactic response of cells that use a "run-and-tumble" strategy in response to environmental cues [17,18]. Here we derive macroscopic equations for the more complex type of behavioral response characteristic of crawling cells, which detect a signal, extract directional information from a scalar concentration field, and change their motile behavior accordingly. We present several models of increasing complexity for which the derivation of population-level equations is possible, and we show how experimentally measured statistics can be obtained from the transport equation formalism. We also show that amoeboid cells that do not adapt to constant signals can still aggregate in steady gradients, but not in response to periodic waves. This is in contrast to the case of cells that use a "run-and-tumble" strategy, where adaptation is essential.

  13. Derivation of the Simon equation

    NASA Astrophysics Data System (ADS)

    Fedorov, P. P.

    2016-09-01

    The form of the empirical Simon equation describing the dependence of the phase-transition temperature on pressure is shown to be asymptotically strict when the system tends to absolute zero of temperature, and then only for crystalline phases.

  14. Friedmann equation with quantum potential

    SciTech Connect

    Siong, Ch'ng Han; Radiman, Shahidan; Nikouravan, Bijan

    2013-11-27

    Friedmann equations are used to describe the evolution of the universe. Solving Friedmann equations for the scale factor indicates that the universe starts from an initial singularity where all the physical laws break down. However, the Friedmann equations are well describing the late-time or large scale universe. Hence now, many physicists try to find an alternative theory to avoid this initial singularity. In this paper, we generate a version of first Friedmann equation which is added with an additional term. This additional term contains the quantum potential energy which is believed to play an important role at small scale. However, it will gradually become negligible when the universe evolves to large scale.

  15. Hidden Statistics of Schroedinger Equation

    NASA Technical Reports Server (NTRS)

    Zak, Michail

    2011-01-01

    Work was carried out in determination of the mathematical origin of randomness in quantum mechanics and creating a hidden statistics of Schr dinger equation; i.e., to expose the transitional stochastic process as a "bridge" to the quantum world. The governing equations of hidden statistics would preserve such properties of quantum physics as superposition, entanglement, and direct-product decomposability while allowing one to measure its state variables using classical methods.

  16. Fractional generalization of Liouville equations.

    PubMed

    Tarasov, Vasily E

    2004-03-01

    In this paper fractional generalization of Liouville equation is considered. We derive fractional analog of normalization condition for distribution function. Fractional generalization of the Liouville equation for dissipative and Hamiltonian systems was derived from the fractional normalization condition. This condition is considered as a normalization condition for systems in fractional phase space. The interpretation of the fractional space is discussed. Copyright 2004 American Institute of Physics.

  17. Wave equations for pulse propagation

    SciTech Connect

    Shore, B.W.

    1987-06-24

    Theoretical discussions of the propagation of pulses of laser radiation through atomic or molecular vapor rely on a number of traditional approximations for idealizing the radiation and the molecules, and for quantifying their mutual interaction by various equations of propagation (for the radiation) and excitation (for the molecules). In treating short-pulse phenomena it is essential to consider coherent excitation phenomena of the sort that is manifest in Rabi oscillations of atomic or molecular populations. Such processes are not adequately treated by rate equations for excitation nor by rate equations for radiation. As part of a more comprehensive treatment of the coupled equations that describe propagation of short pulses, this memo presents background discussion of the equations that describe the field. This memo discusses the origin, in Maxwell's equations, of the wave equation used in the description of pulse propagation. It notes the separation into lamellar and solenoidal (or longitudinal and transverse) and positive and negative frequency parts. It mentions the possibility of separating the polarization field into linear and nonlinear parts, in order to define a susceptibility or index of refraction and, from these, a phase and group velocity. The memo discusses various ways of characterizing the polarization characteristics of plane waves, that is, of parameterizing a transverse unit vector, such as the Jones vector, the Stokes vector, and the Poincare sphere. It discusses the connection between macroscopically defined quantities, such as the intensity or, more generally, the Stokes parameters, and microscopic field amplitudes. The material presented here is a portion of a more extensive treatment of propagation to be presented separately. The equations presented here have been described in various books and articles. They are collected here as a summary and review of theory needed when treating pulse propagation.

  18. Program solves line flow equation

    SciTech Connect

    McCaslin, K.P.

    1981-01-19

    A program written for the TI-59 programmable calculator solves the Panhandle Eastern A equation - an industry-accepted equation for calculating pressure losses in high-pressure gas-transmission pipelines. The input variables include the specific gravity of the gas, the flowing temperature, the pipeline efficiency, the base temperature and pressure, the inlet pressure, the pipeline's length and inside diameter, and the flow rate (SCF/day); the program solves for the discharge pressure.

  19. An Exact Mapping from Navier-Stokes Equation to Schr"odinger Equation via Riccati Equation

    NASA Astrophysics Data System (ADS)

    Christianto, Vic; Smarandache, Florentin

    2010-03-01

    In the present article we argue that it is possible to write down Schr"odinger representation of Navier-Stokes equation via Riccati equation. The proposed approach, while differs appreciably from other method such as what is proposed by R. M. Kiehn, has an advantage, i.e. it enables us extend further to quaternionic and biquaternionic version of Navier-Stokes equation, for instance via Kravchenko's and Gibbon's route. Further observation is of course recommended in order to refute or verify this proposition.

  20. The soil moisture velocity equation

    NASA Astrophysics Data System (ADS)

    Ogden, Fred L.; Allen, Myron B.; Lai, Wencong; Zhu, Jianting; Seo, Mookwon; Douglas, Craig C.; Talbot, Cary A.

    2017-06-01

    Numerical solution of the one-dimensional Richards' equation is the recommended method for coupling groundwater to the atmosphere through the vadose zone in hyperresolution Earth system models, but requires fine spatial discretization, is computationally expensive, and may not converge due to mathematical degeneracy or when sharp wetting fronts occur. We transformed the one-dimensional Richards' equation into a new equation that describes the velocity of moisture content values in an unsaturated soil under the actions of capillarity and gravity. We call this new equation the Soil Moisture Velocity Equation (SMVE). The SMVE consists of two terms: an advection-like term that accounts for gravity and the integrated capillary drive of the wetting front, and a diffusion-like term that describes the flux due to the shape of the wetting front capillarity profile divided by the vertical gradient of the capillary pressure head. The SMVE advection-like term can be converted to a relatively easy to solve ordinary differential equation (ODE) using the method of lines and solved using a finite moisture-content discretization. Comparing against analytical solutions of Richards' equation shows that the SMVE advection-like term is >99% accurate for calculating infiltration fluxes neglecting the diffusion-like term. The ODE solution of the SMVE advection-like term is accurate, computationally efficient and reliable for calculating one-dimensional vadose zone fluxes in Earth system and large-scale coupled models of land-atmosphere interaction. It is also well suited for use in inverse problems such as when repeat remote sensing observations are used to infer soil hydraulic properties or soil moisture.Plain Language SummarySince its original publication in 1922, the so-called Richards' <span class="hlt">equation</span> has been the only rigorous way to couple groundwater to the land surface through the unsaturated zone that lies between the water table and land</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70012994','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70012994"><span>Optimization of one-way wave <span class="hlt">equations</span>.</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lee, M.W.; Suh, S.Y.</p> <p>1985-01-01</p> <p>The theory of wave extrapolation is based on the square-root <span class="hlt">equation</span> or one-way <span class="hlt">equation</span>. The full wave <span class="hlt">equation</span> represents waves which propagate in both directions. On the contrary, the square-root <span class="hlt">equation</span> represents waves propagating in one direction only. A new optimization method presented here improves the dispersion relation of the one-way wave <span class="hlt">equation</span>. -from Authors</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21202833','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21202833"><span>Linear determining <span class="hlt">equations</span> for differential constraints</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kaptsov, O V</p> <p>1998-12-31</p> <p>A construction of differential constraints compatible with partial differential <span class="hlt">equations</span> is considered. Certain linear determining <span class="hlt">equations</span> with parameters are used to find such differential constraints. They generalize the classical determining <span class="hlt">equations</span> used in the search for admissible Lie operators. As applications of this approach <span class="hlt">equations</span> of an ideal incompressible fluid and non-linear heat <span class="hlt">equations</span> are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920002099','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920002099"><span>Turbulent fluid motion 3: Basic continuum <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Deissler, Robert G.</p> <p>1991-01-01</p> <p>A derivation of the continuum <span class="hlt">equations</span> used for the analysis of turbulence is given. These <span class="hlt">equations</span> include the continuity <span class="hlt">equation</span>, the Navier-Stokes <span class="hlt">equations</span>, and the heat transfer or energy <span class="hlt">equation</span>. An experimental justification for using a continuum approach for the study of turbulence is given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015CoPhC.192..156D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015CoPhC.192..156D"><span>Solving Parker's transport <span class="hlt">equation</span> with stochastic differential <span class="hlt">equations</span> on GPUs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dunzlaff, P.; Strauss, R. D.; Potgieter, M. S.</p> <p>2015-07-01</p> <p>The numerical solution of transport <span class="hlt">equations</span> for energetic charged particles in space is generally very costly in terms of time. Besides the use of multi-core CPUs and computer clusters in order to decrease the computation times, high performance calculations on graphics processing units (GPUs) have become available during the last years. In this work we introduce and describe a GPU-accelerated implementation of Parker's <span class="hlt">equation</span> using Stochastic Differential <span class="hlt">Equations</span> (SDEs) for the simulation of the transport of energetic charged particles with the CUDA toolkit, which is the focus of this work. We briefly discuss the set of SDEs arising from Parker's transport <span class="hlt">equation</span> and their application to boundary value problems such as that of the Jovian magnetosphere. We compare the runtimes of the GPU code with a CPU version of the same algorithm. Compared to the CPU implementation (using OpenMP and eight threads) we find a performance increase of about a factor of 10-60, depending on the assumed set of parameters. Furthermore, we benchmark our simulation using the results of an existing SDE implementation of Parker's transport <span class="hlt">equation</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JMP....53j3520V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JMP....53j3520V"><span>Fredholm's <span class="hlt">equations</span> for subwavelength focusing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Velázquez-Arcos, J. M.</p> <p>2012-10-01</p> <p>Subwavelength focusing (SF) is a very useful tool that can be carried out with the use of left hand materials for optics that involve the range of the microwaves. Many recent works have described a successful alternative procedure using time reversal methods. The advantage is that we do not need devices which require the complicated manufacture of left-hand materials; nevertheless, the theoretical mathematical bases are far from complete because before now we lacked an adequate easy-to-apply frame. In this work we give, for a broad class of discrete systems, a solid support for the theory of electromagnetic SF that can be applied to communications and nanotechnology. The very central procedure is the development of vector-matrix formalism (VMF) based on exploiting both the inhomogeneous and homogeneous Fredholm's integral <span class="hlt">equations</span> in cases where the last two kinds of integral <span class="hlt">equations</span> are applied to some selected discrete systems. To this end, we first establish a generalized Newmann series for the Fourier transform of the Green's function in the inhomogeneous Fredholm's <span class="hlt">equation</span> of the problem. Then we go from an integral operator <span class="hlt">equation</span> to a vector-matrix algebraic one. In this way we explore the inhomogeneous case and later on also the very interesting one about the homogeneous <span class="hlt">equation</span>. Thus, on the one hand we can relate in a simple manner the arriving electromagnetic signals with those at their sources and we can use them to perform a SF. On the other hand, we analyze the homogeneous version of the <span class="hlt">equations</span>, finding resonant solutions that have analogous properties to their counterparts in quantum mechanical scattering, that can be used in a proposed very powerful way in communications. Also we recover quantum mechanical operator relations that are identical for classical electromagnetics. Finally, we prove two theorems that formalize the relation between the theory of Fredholm's integral <span class="hlt">equations</span> and the VMF we present here.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28297844','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28297844"><span>Cable <span class="hlt">equation</span> for general geometry.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>López-Sánchez, Erick J; Romero, Juan M</p> <p>2017-02-01</p> <p>The cable <span class="hlt">equation</span> describes the voltage in a straight cylindrical cable, and this model has been employed to model electrical potential in dendrites and axons. However, sometimes this <span class="hlt">equation</span> might give incorrect predictions for some realistic geometries, in particular when the radius of the cable changes significantly. Cables with a nonconstant radius are important for some phenomena, for example, discrete swellings along the axons appear in neurodegenerative diseases such as Alzheimers, Parkinsons, human immunodeficiency virus associated dementia, and multiple sclerosis. In this paper, using the Frenet-Serret frame, we propose a generalized cable <span class="hlt">equation</span> for a general cable geometry. This generalized <span class="hlt">equation</span> depends on geometric quantities such as the curvature and torsion of the cable. We show that when the cable has a constant circular cross section, the first fundamental form of the cable can be simplified and the generalized cable <span class="hlt">equation</span> depends on neither the curvature nor the torsion of the cable. Additionally, we find an exact solution for an ideal cable which has a particular variable circular cross section and zero curvature. For this case we show that when the cross section of the cable increases the voltage decreases. Inspired by this ideal case, we rewrite the generalized cable <span class="hlt">equation</span> as a diffusion <span class="hlt">equation</span> with a source term generated by the cable geometry. This source term depends on the cable cross-sectional area and its derivates. In addition, we study different cables with swelling and provide their numerical solutions. The numerical solutions show that when the cross section of the cable has abrupt changes, its voltage is smaller than the voltage in the cylindrical cable. Furthermore, these numerical solutions show that the voltage can be affected by geometrical inhomogeneities on the cable.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PhRvE..95b2403L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PhRvE..95b2403L"><span>Cable <span class="hlt">equation</span> for general geometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>López-Sánchez, Erick J.; Romero, Juan M.</p> <p>2017-02-01</p> <p>The cable <span class="hlt">equation</span> describes the voltage in a straight cylindrical cable, and this model has been employed to model electrical potential in dendrites and axons. However, sometimes this <span class="hlt">equation</span> might give incorrect predictions for some realistic geometries, in particular when the radius of the cable changes significantly. Cables with a nonconstant radius are important for some phenomena, for example, discrete swellings along the axons appear in neurodegenerative diseases such as Alzheimers, Parkinsons, human immunodeficiency virus associated dementia, and multiple sclerosis. In this paper, using the Frenet-Serret frame, we propose a generalized cable <span class="hlt">equation</span> for a general cable geometry. This generalized <span class="hlt">equation</span> depends on geometric quantities such as the curvature and torsion of the cable. We show that when the cable has a constant circular cross section, the first fundamental form of the cable can be simplified and the generalized cable <span class="hlt">equation</span> depends on neither the curvature nor the torsion of the cable. Additionally, we find an exact solution for an ideal cable which has a particular variable circular cross section and zero curvature. For this case we show that when the cross section of the cable increases the voltage decreases. Inspired by this ideal case, we rewrite the generalized cable <span class="hlt">equation</span> as a diffusion <span class="hlt">equation</span> with a source term generated by the cable geometry. This source term depends on the cable cross-sectional area and its derivates. In addition, we study different cables with swelling and provide their numerical solutions. The numerical solutions show that when the cross section of the cable has abrupt changes, its voltage is smaller than the voltage in the cylindrical cable. Furthermore, these numerical solutions show that the voltage can be affected by geometrical inhomogeneities on the cable.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA115279','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA115279"><span><span class="hlt">Equation</span> of State of Simple Metals.</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1982-05-10</p> <p>This is the final report of A. L. Ruoff and N. W. Ashcroft on <span class="hlt">Equation</span> of State of Simple Metals. It includes experimental <span class="hlt">equation</span> of state results for potassium and theoretical calculations of its <span class="hlt">equation</span> of state . (Author)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=Maxwell+AND+equation&id=EJ844007','ERIC'); return false;" href="https://eric.ed.gov/?q=Maxwell+AND+equation&id=EJ844007"><span>How to Obtain the Covariant Form of Maxwell's <span class="hlt">Equations</span> from the Continuity <span class="hlt">Equation</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Heras, Jose A.</p> <p>2009-01-01</p> <p>The covariant Maxwell <span class="hlt">equations</span> are derived from the continuity <span class="hlt">equation</span> for the electric charge. This result provides an axiomatic approach to Maxwell's <span class="hlt">equations</span> in which charge conservation is emphasized as the fundamental axiom underlying these <span class="hlt">equations</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Conservation&pg=7&id=EJ844007','ERIC'); return false;" href="http://eric.ed.gov/?q=Conservation&pg=7&id=EJ844007"><span>How to Obtain the Covariant Form of Maxwell's <span class="hlt">Equations</span> from the Continuity <span class="hlt">Equation</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Heras, Jose A.</p> <p>2009-01-01</p> <p>The covariant Maxwell <span class="hlt">equations</span> are derived from the continuity <span class="hlt">equation</span> for the electric charge. This result provides an axiomatic approach to Maxwell's <span class="hlt">equations</span> in which charge conservation is emphasized as the fundamental axiom underlying these <span class="hlt">equations</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA470361','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA470361"><span>Spectral Models Based on Boussinesq <span class="hlt">Equations</span></span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2006-10-03</p> <p><span class="hlt">equations</span> assume periodic solutions apriori. This, however, also forces the question of which extended Boussinesq model to use. Various one- <span class="hlt">equation</span> ... <span class="hlt">equations</span> of Nwogu (1993), without the traditional reduction to a one- <span class="hlt">equation</span> model. Optimal numerical techniques to solve this system of <span class="hlt">equations</span> are...A. and Madsen, P. A. (2004). "Boussinesq evolution <span class="hlt">equations</span> : numerical efficiency, breaking and amplitude dispersion," Coastal Engineering, 51, 1117</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADD095338','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADD095338"><span>An <span class="hlt">Equation</span> of State for Fluid Ethylene.</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p></p> <p>an <span class="hlt">equation</span> of state , vapor pressure <span class="hlt">equation</span>, and <span class="hlt">equation</span> for the ideal gas heat capacity. The coefficients were determined by a least squares fit...of selected experimental data. Comparisons of property values calculated using the <span class="hlt">equation</span> of state with measured values are given. The <span class="hlt">equation</span> of state is...vapor phases for temperatures from the freezing line of 450 K with pressures to 40 MPa are presented. The <span class="hlt">equation</span> of state and its derivative and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/AD0739592','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/AD0739592"><span>Nonlinear Evolution <span class="hlt">Equations</span> in Banach Spaces.</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p></p> <p>relationship to the evolution <span class="hlt">equation</span> is studied. The results obtained extend several known existence theorems and provide generalized solutions of the evolution <span class="hlt">equation</span> in more general cases. (Author)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21230210','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21230210"><span>Numerical integration of variational <span class="hlt">equations</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Skokos, Ch; Gerlach, E</p> <p>2010-09-01</p> <p>We present and compare different numerical schemes for the integration of the variational <span class="hlt">equations</span> of autonomous Hamiltonian systems whose kinetic energy is quadratic in the generalized momenta and whose potential is a function of the generalized positions. We apply these techniques to Hamiltonian systems of various degrees of freedom and investigate their efficiency in accurately reproducing well-known properties of chaos indicators such as the Lyapunov characteristic exponents and the generalized alignment indices. We find that the best numerical performance is exhibited by the "tangent map method," a scheme based on symplectic integration techniques which proves to be optimal in speed and accuracy. According to this method, a symplectic integrator is used to approximate the solution of the Hamilton <span class="hlt">equations</span> of motion by the repeated action of a symplectic map S , while the corresponding tangent map TS is used for the integration of the variational <span class="hlt">equations</span>. A simple and systematic technique to construct TS is also presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007SPIE.6597E..09U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007SPIE.6597E..09U"><span>Integration of quantum hydrodynamical <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ulyanova, Vera G.; Sanin, Andrey L.</p> <p>2007-04-01</p> <p>Quantum hydrodynamics <span class="hlt">equations</span> describing the dynamics of quantum fluid are a subject of this report (QFD).These <span class="hlt">equations</span> can be used to decide the wide class of problem. But there are the calculated difficulties for the <span class="hlt">equations</span>, which take place for nonlinear hyperbolic systems. In this connection, It is necessary to impose the additional restrictions which assure the existence and unique of solutions. As test sample, we use the free wave packet and study its behavior at the different initial and boundary conditions. The calculations of wave packet propagation cause in numerical algorithm the division. In numerical algorithm at the calculations of wave packet propagation, there arises the problem of division by zero. To overcome this problem we have to sew together discrete numerical and analytical continuous solutions on the boundary. We demonstrate here for the free wave packet that the numerical solution corresponds to the analytical solution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016IJMES..47..552L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016IJMES..47..552L"><span>Students' understanding of quadratic <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>López, Jonathan; Robles, Izraim; Martínez-Planell, Rafael</p> <p>2016-05-01</p> <p>Action-Process-Object-Schema theory (APOS) was applied to study student understanding of quadratic <span class="hlt">equations</span> in one variable. This required proposing a detailed conjecture (called a genetic decomposition) of mental constructions students may do to understand quadratic <span class="hlt">equations</span>. The genetic decomposition which was proposed can contribute to help students achieve an understanding of quadratic <span class="hlt">equations</span> with improved interrelation of ideas and more flexible application of solution methods. Semi-structured interviews with eight beginning undergraduate students explored which of the mental constructions conjectured in the genetic decomposition students could do, and which they had difficulty doing. Two of the mental constructions that form part of the genetic decomposition are highlighted and corresponding further data were obtained from the written work of 121 undergraduate science and engineering students taking a multivariable calculus course. The results suggest the importance of explicitly considering these two highlighted mental constructions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009LNCS.5720..104W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009LNCS.5720..104W"><span>Differential <span class="hlt">Equations</span> for Morphological Amoebas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Welk, Martin; Breuß, Michael; Vogel, Oliver</p> <p></p> <p>This paper is concerned with amoeba median filtering, a structure-adaptive morphological image filter. It has been introduced by Lerallut et al. in a discrete formulation. Experimental evidence shows that iterated amoeba median filtering leads to segmentation-like results that are similar to those obtained by self-snakes, an image filter based on a partial differential <span class="hlt">equation</span>. We investigate this correspondence by analysing a space-continuous formulation of iterated median filtering. We prove that in the limit of vanishing radius of the structuring elements, iterated amoeba median filtering indeed approximates a partial differential <span class="hlt">equation</span> related to self-snakes and the well-known (mean) curvature motion <span class="hlt">equation</span>. We present experiments with discrete iterated amoeba median filtering that confirm qualitative and quantitative predictions of our analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003JChPh.119.2165S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003JChPh.119.2165S"><span>Fractional reaction-diffusion <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Seki, Kazuhiko; Wojcik, Mariusz; Tachiya, M.</p> <p>2003-07-01</p> <p>A fractional reaction-diffusion <span class="hlt">equation</span> is derived from a continuous time random walk model when the transport is dispersive. The exit from the encounter distance, which is described by the algebraic waiting time distribution of jump motion, interferes with the reaction at the encounter distance. Therefore, the reaction term has a memory effect. The derived <span class="hlt">equation</span> is applied to the geminate recombination problem. The recombination is shown to depend on the intrinsic reaction rate, in contrast with the results of Sung et al. [J. Chem. Phys. 116, 2338 (2002)], which were obtained from the fractional reaction-diffusion <span class="hlt">equation</span> where the diffusion term has a memory effect but the reaction term does not. The reactivity dependence of the recombination probability is confirmed by numerical simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2890680','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2890680"><span>Fractional-calculus diffusion <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2010-01-01</p> <p>Background Sequel to the work on the quantization of nonconservative systems using fractional calculus and quantization of a system with Brownian motion, which aims to consider the dissipation effects in quantum-mechanical description of microscale systems. Results The canonical quantization of a system represented classically by one-dimensional Fick's law, and the diffusion <span class="hlt">equation</span> is carried out according to the Dirac method. A suitable Lagrangian, and Hamiltonian, describing the diffusive system, are constructed and the Hamiltonian is transformed to Schrodinger's <span class="hlt">equation</span> which is solved. An application regarding implementation of the developed mathematical method to the analysis of diffusion, osmosis, which is a biological application of the diffusion process, is carried out. Schrödinger's <span class="hlt">equation</span> is solved. Conclusions The plot of the probability function represents clearly the dissipative and drift forces and hence the osmosis, which agrees totally with the macro-scale view, or the classical-version osmosis. PMID:20492677</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhRvE..90f3307P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhRvE..90f3307P"><span>Numerical optimization using flow <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Punk, Matthias</p> <p>2014-12-01</p> <p>We develop a method for multidimensional optimization using flow <span class="hlt">equations</span>. This method is based on homotopy continuation in combination with a maximum entropy approach. Extrema of the optimizing functional correspond to fixed points of the flow <span class="hlt">equation</span>. While ideas based on Bayesian inference such as the maximum entropy method always depend on a prior probability, the additional step in our approach is to perform a continuous update of the prior during the homotopy flow. The prior probability thus enters the flow <span class="hlt">equation</span> only as an initial condition. We demonstrate the applicability of this optimization method for two paradigmatic problems in theoretical condensed matter physics: numerical analytic continuation from imaginary to real frequencies and finding (variational) ground states of frustrated (quantum) Ising models with random or long-range antiferromagnetic interactions.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25615222','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25615222"><span>Numerical optimization using flow <span class="hlt">equations</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Punk, Matthias</p> <p>2014-12-01</p> <p>We develop a method for multidimensional optimization using flow <span class="hlt">equations</span>. This method is based on homotopy continuation in combination with a maximum entropy approach. Extrema of the optimizing functional correspond to fixed points of the flow <span class="hlt">equation</span>. While ideas based on Bayesian inference such as the maximum entropy method always depend on a prior probability, the additional step in our approach is to perform a continuous update of the prior during the homotopy flow. The prior probability thus enters the flow <span class="hlt">equation</span> only as an initial condition. We demonstrate the applicability of this optimization method for two paradigmatic problems in theoretical condensed matter physics: numerical analytic continuation from imaginary to real frequencies and finding (variational) ground states of frustrated (quantum) Ising models with random or long-range antiferromagnetic interactions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17927422','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17927422"><span>The room acoustic rendering <span class="hlt">equation</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Siltanen, Samuel; Lokki, Tapio; Kiminki, Sami; Savioja, Lauri</p> <p>2007-09-01</p> <p>An integral <span class="hlt">equation</span> generalizing a variety of known geometrical room acoustics modeling algorithms is presented. The formulation of the room acoustic rendering <span class="hlt">equation</span> is adopted from computer graphics. Based on the room acoustic rendering <span class="hlt">equation</span>, an acoustic radiance transfer method, which can handle both diffuse and nondiffuse reflections, is derived. In a case study, the method is used to predict several acoustic parameters of a room model. The results are compared to measured data of the actual room and to the results given by other acoustics prediction software. It is concluded that the method can predict most acoustic parameters reliably and provides results as accurate as current commercial room acoustic prediction software. Although the presented acoustic radiance transfer method relies on geometrical acoustics, it can be extended to model diffraction and transmission through materials in future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017CMMPh..57..211V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017CMMPh..57..211V"><span>Special solutions to Chazy <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Varin, V. P.</p> <p>2017-02-01</p> <p>We consider the classical Chazy <span class="hlt">equation</span>, which is known to be integrable in hypergeometric functions. But this solution has remained purely existential and was never used numerically. We give explicit formulas for hypergeometric solutions in terms of initial data. A special solution was found in the upper half plane H with the same tessellation of H as that of the modular group. This allowed us to derive some new identities for the Eisenstein series. We constructed a special solution in the unit disk and gave an explicit description of singularities on its natural boundary. A global solution to Chazy <span class="hlt">equation</span> in elliptic and theta functions was found that allows parametrization of an arbitrary solution to Chazy <span class="hlt">equation</span>. The results have applications to analytic number theory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22525840','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22525840"><span>Explicit integration of Friedmann's <span class="hlt">equation</span> with nonlinear <span class="hlt">equations</span> of state</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chen, Shouxin; Gibbons, Gary W.; Yang, Yisong E-mail: gwg1@damtp.cam.ac.uk</p> <p>2015-05-01</p> <p>In this paper we study the integrability of the Friedmann <span class="hlt">equations</span>, when the <span class="hlt">equation</span> of state for the perfect-fluid universe is nonlinear, in the light of the Chebyshev theorem. A series of important, yet not previously touched, problems will be worked out which include the generalized Chaplygin gas, two-term energy density, trinomial Friedmann, Born-Infeld, two-fluid models, and Chern-Simons modified gravity theory models. With the explicit integration, we are able to understand exactly the roles of the physical parameters in various models play in the cosmological evolution which may also offer clues to a profound understanding of the problems in general settings. For example, in the Chaplygin gas universe, a few integrable cases lead us to derive a universal formula for the asymptotic exponential growth rate of the scale factor, of an explicit form, whether the Friedmann <span class="hlt">equation</span> is integrable or not, which reveals the coupled roles played by various physical sectors and it is seen that, as far as there is a tiny presence of nonlinear matter, conventional linear matter makes contribution to the dark matter, which becomes significant near the phantom divide line. The Friedmann <span class="hlt">equations</span> also arise in areas of physics not directly related to cosmology. We provide some examples ranging from geometric optics and central orbits to soap films and the shape of glaciated valleys to which our results may be applied.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009APS..DPPNI3001C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009APS..DPPNI3001C"><span>Transport <span class="hlt">Equations</span> In Tokamak Plasmas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Callen, J. D.</p> <p>2009-11-01</p> <p>Tokamak plasma transport <span class="hlt">equations</span> are usually obtained by flux surface averaging the collisional Braginskii <span class="hlt">equations</span>. However, tokamak plasmas are not in collisional regimes. Also, ad hoc terms are added for: neoclassical effects on the parallel Ohm's law (trapped particle effects on resistivity, bootstrap current); fluctuation-induced transport; heating, current-drive and flow sources and sinks; small B field non-axisymmetries; magnetic field transients etc. A set of self-consistent second order in gyroradius fluid-moment-based transport <span class="hlt">equations</span> for nearly axisymmetric tokamak plasmas has been developed recently using a kinetic-based framework. The derivation uses neoclassical-based parallel viscous force closures, and includes all the effects noted above. Plasma processes on successive time scales (and constraints they impose) are considered sequentially: compressional Alfv'en waves (Grad-Shafranov equilibrium, ion radial force balance); sound waves (pressure constant along field lines, incompressible flows within a flux surface); and ion collisions (damping of poloidal flow). Radial particle fluxes are driven by the many second order in gyroradius toroidal angular torques on the plasma fluid: 7 ambipolar collision-based ones (classical, neoclassical, etc.) and 8 non-ambipolar ones (fluctuation-induced, polarization flows from toroidal rotation transients etc.). The plasma toroidal rotation <span class="hlt">equation</span> [1] results from setting to zero the net radial current induced by the non-ambipolar fluxes. The radial particle flux consists of the collision-based intrinsically ambipolar fluxes plus the non-ambipolar fluxes evaluated at the ambipolarity-enforcing toroidal plasma rotation (radial electric field). The energy transport <span class="hlt">equations</span> do not involve an ambipolar constraint and hence are more directly obtained. The resultant transport <span class="hlt">equations</span> will be presented and contrasted with the usual ones. [4pt] [1] J.D. Callen, A.J. Cole, C.C. Hegna, ``Toroidal Rotation In</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21371198','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21371198"><span>Transport <span class="hlt">equations</span> in tokamak plasmas</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Callen, J. D.; Hegna, C. C.; Cole, A. J.</p> <p>2010-05-15</p> <p>Tokamak plasma transport <span class="hlt">equations</span> are usually obtained by flux surface averaging the collisional Braginskii <span class="hlt">equations</span>. However, tokamak plasmas are not in collisional regimes. Also, ad hoc terms are added for neoclassical effects on the parallel Ohm's law, fluctuation-induced transport, heating, current-drive and flow sources and sinks, small magnetic field nonaxisymmetries, magnetic field transients, etc. A set of self-consistent second order in gyroradius fluid-moment-based transport <span class="hlt">equations</span> for nearly axisymmetric tokamak plasmas has been developed using a kinetic-based approach. The derivation uses neoclassical-based parallel viscous force closures, and includes all the effects noted above. Plasma processes on successive time scales and constraints they impose are considered sequentially: compressional Alfven waves (Grad-Shafranov equilibrium, ion radial force balance), sound waves (pressure constant along field lines, incompressible flows within a flux surface), and collisions (electrons, parallel Ohm's law; ions, damping of poloidal flow). Radial particle fluxes are driven by the many second order in gyroradius toroidal angular torques on a plasma species: seven ambipolar collision-based ones (classical, neoclassical, etc.) and eight nonambipolar ones (fluctuation-induced, polarization flows from toroidal rotation transients, etc.). The plasma toroidal rotation <span class="hlt">equation</span> results from setting to zero the net radial current induced by the nonambipolar fluxes. The radial particle flux consists of the collision-based intrinsically ambipolar fluxes plus the nonambipolar fluxes evaluated at the ambipolarity-enforcing toroidal plasma rotation (radial electric field). The energy transport <span class="hlt">equations</span> do not involve an ambipolar constraint and hence are more directly obtained. The 'mean field' effects of microturbulence on the parallel Ohm's law, poloidal ion flow, particle fluxes, and toroidal momentum and energy transport are all included self-consistently. The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GrCo...23..280D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GrCo...23..280D"><span>Einstein <span class="hlt">equations</span> with fluctuating volume</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dzhunushaliev, Vladimir; Quevedo, Hernando</p> <p>2017-07-01</p> <p>We develop a simple model to study classical fields on the background of a fluctuating spacetime volume. It is applied to formulate the stochastic Einstein <span class="hlt">equations</span> with a perfect-fluid source. We investigate the particular case of a stochastic Friedmann-Lema\\^itre-Robertson-Walker cosmology, and show that the resulting field <span class="hlt">equations</span> can lead to solutions which avoid the initial big bang singularity. By interpreting the fluctuations as the result of the presence of a quantum spacetime, we conclude that classical singularities can be avoided even within a stochastic model that include quantum effects in a very simple manner.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6961552','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6961552"><span>The nuclear <span class="hlt">equation</span> of state</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kahana, S.</p> <p>1986-01-01</p> <p>The role of the nuclear <span class="hlt">equation</span> of state in determining the fate of the collapsing cores of massive stars is examined in light of both recent theoretical advances in this subject and recent experimental measurements with relativistic heavy ions. The difficulties existing in attempts to bring the softer nuclear matter apparently required by the theory of Type II supernovae into consonance with the heavy ion data are discussed. Relativistic mean field theory is introduced as a candidate for derivation of the <span class="hlt">equation</span> of state, and a simple form for the saturation compressibility is obtained. 28 refs., 4 figs., 1 tab.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhRvL.111i6101S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhRvL.111i6101S"><span>Young's <span class="hlt">Equation</span> at the Nanoscale</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Seveno, David; Blake, Terence D.; De Coninck, Joël</p> <p>2013-08-01</p> <p>In 1805, Thomas Young was the first to propose an <span class="hlt">equation</span> to predict the value of the equilibrium contact angle of a liquid on a solid. Today, the force exerted by a liquid on a solid, such as a flat plate or fiber, is routinely used to assess this angle. Moreover, it has recently become possible to study wetting at the nanoscale using an atomic force microscope. Here, we report the use of molecular-dynamics simulations to investigate the force distribution along a 15 nm fiber dipped into a liquid meniscus. We find very good agreement between the measured force and that predicted by Young’s <span class="hlt">equation</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/945516','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/945516"><span>Tantalum <span class="hlt">equation</span> of state package</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Young, D A; Orlikowski, D</p> <p>2008-12-04</p> <p>We provide here the tantalum <span class="hlt">equation</span> of state (EOS) over broad ranges of temperature and pressure (up to 49,900 K and 9.6 Mbar). This EOS was developed by the quotidian <span class="hlt">equation</span> of state methodology, which is a robust EOS model providing EOS tables for high pressure hydrodynamic simulations. The included tables span densities 5-33.4 g/cc with 51 entries and temperatures 116-49,900 K with 50 entries. There are 16 quantities as a function of that density-temperature grid, which are provided in this EOS package and are listed in the Appendix (Table I).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24730966','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24730966"><span>Investigation of the kinetic model <span class="hlt">equations</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Sha; Zhong, Chengwen</p> <p>2014-03-01</p> <p>Currently the Boltzmann <span class="hlt">equation</span> and its model <span class="hlt">equations</span> are widely used in numerical predictions for dilute gas flows. The nonlinear integro-differential Boltzmann <span class="hlt">equation</span> is the fundamental <span class="hlt">equation</span> in the kinetic theory of dilute monatomic gases. By replacing the nonlinear fivefold collision integral term by a nonlinear relaxation term, its model <span class="hlt">equations</span> such as the famous Bhatnagar-Gross-Krook (BGK) <span class="hlt">equation</span> are mathematically simple. Since the computational cost of solving model <span class="hlt">equations</span> is much less than that of solving the full Boltzmann <span class="hlt">equation</span>, the model <span class="hlt">equations</span> are widely used in predicting rarefied flows, multiphase flows, chemical flows, and turbulent flows although their predictions are only qualitatively right for highly nonequilibrium flows in transitional regime. In this paper the differences between the Boltzmann <span class="hlt">equation</span> and its model <span class="hlt">equations</span> are investigated aiming at giving guidelines for the further development of kinetic models. By comparing the Boltzmann <span class="hlt">equation</span> and its model <span class="hlt">equations</span> using test cases with different nonequilibrium types, two factors (the information held by nonequilibrium moments and the different relaxation rates of high- and low-speed molecules) are found useful for adjusting the behaviors of modeled collision terms in kinetic regime. The usefulness of these two factors are confirmed by a generalized model collision term derived from a mathematical relation between the Boltzmann <span class="hlt">equation</span> and BGK <span class="hlt">equation</span> that is also derived in this paper. After the analysis of the difference between the Boltzmann <span class="hlt">equation</span> and the BGK <span class="hlt">equation</span>, an attempt at approximating the collision term is proposed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=equations+AND+states&pg=4&id=EJ753914','ERIC'); return false;" href="http://eric.ed.gov/?q=equations+AND+states&pg=4&id=EJ753914"><span>The Forced Soft Spring <span class="hlt">Equation</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Fay, T. H.</p> <p>2006-01-01</p> <p>Through numerical investigations, this paper studies examples of the forced Duffing type spring <span class="hlt">equation</span> with [epsilon] negative. By performing trial-and-error numerical experiments, the existence is demonstrated of stability boundaries in the phase plane indicating initial conditions yielding bounded solutions. Subharmonic boundaries are…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=pendulum&pg=3&id=EJ831639','ERIC'); return false;" href="http://eric.ed.gov/?q=pendulum&pg=3&id=EJ831639"><span>Pendulum Motion and Differential <span class="hlt">Equations</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Reid, Thomas F.; King, Stephen C.</p> <p>2009-01-01</p> <p>A common example of real-world motion that can be modeled by a differential <span class="hlt">equation</span>, and one easily understood by the student, is the simple pendulum. Simplifying assumptions are necessary for closed-form solutions to exist, and frequently there is little discussion of the impact if those assumptions are not met. This article presents a…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeoJI.208.1567L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeoJI.208.1567L"><span>Wave-<span class="hlt">equation</span> dispersion inversion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Jing; Feng, Zongcai; Schuster, Gerard</p> <p>2017-03-01</p> <p>We present the theory for wave-<span class="hlt">equation</span> inversion of dispersion curves, where the misfit function is the sum of the squared differences between the wavenumbers along the predicted and observed dispersion curves. The dispersion curves are obtained from Rayleigh waves recorded by vertical-component geophones. Similar to wave-<span class="hlt">equation</span> traveltime tomography, the complicated surface wave arrivals in traces are skeletonized as simpler data, namely the picked dispersion curves in the phase-velocity and frequency domains. Solutions to the elastic wave <span class="hlt">equation</span> and an iterative optimization method are then used to invert these curves for 2-D or 3-D S-wave velocity models. This procedure, denoted as wave-<span class="hlt">equation</span> dispersion inversion (WD), does not require the assumption of a layered model and is significantly less prone to the cycle-skipping problems of full waveform inversion. The synthetic and field data examples demonstrate that WD can approximately reconstruct the S-wave velocity distributions in laterally heterogeneous media if the dispersion curves can be identified and picked. The WD method is easily extended to anisotropic data and the inversion of dispersion curves associated with Love waves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/1391','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/1391"><span>Simple, Flexible, Trigonometric Taper <span class="hlt">Equations</span></span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Charles E. Thomas; Bernard R. Parresol</p> <p>1991-01-01</p> <p>There have been numerous approaches to modeling stem form in recent decades. The majority have concentrated on the simpler coniferous bole form and have become increasingly complex mathematical expressions. Use of trigonometric <span class="hlt">equations</span> provides a simple expression of taper that is flexible enough to fit both coniferous and hard-wood bole forms. As an illustration, we...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6742124','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6742124"><span>Empirical <span class="hlt">equation</span> estimates geothermal gradients</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kutasov, I.M. )</p> <p>1995-01-02</p> <p>An empirical <span class="hlt">equation</span> can estimate geothermal (natural) temperature profiles in new exploration areas. These gradients are useful for cement slurry and mud design and for improving electrical and temperature log interpretation. Downhole circulating temperature logs and surface outlet temperatures are used for predicting the geothermal gradients.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740012057','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740012057"><span>The solution of transcendental <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Agrawal, K. M.; Outlaw, R.</p> <p>1973-01-01</p> <p>Some of the existing methods to globally approximate the roots of transcendental <span class="hlt">equations</span> namely, Graeffe's method, are studied. Summation of the reciprocated roots, Whittaker-Bernoulli method, and the extension of Bernoulli's method via Koenig's theorem are presented. The Aitken's delta squared process is used to accelerate the convergence. Finally, the suitability of these methods is discussed in various cases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED502442.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED502442.pdf"><span>Renaissance Learning <span class="hlt">Equating</span> Study. Report</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Sewell, Julie; Sainsbury, Marian; Pyle, Katie; Keogh, Nikki; Styles, Ben</p> <p>2007-01-01</p> <p>An <span class="hlt">equating</span> study was carried out in autumn 2006 by the National Foundation for Educational Research (NFER) on behalf of Renaissance Learning, to provide validation evidence for the use of the Renaissance Star Reading and Star Mathematics tests in English schools. The study investigated the correlation between the Star tests and established tests.…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=Stephen+AND+king&pg=7&id=EJ831639','ERIC'); return false;" href="https://eric.ed.gov/?q=Stephen+AND+king&pg=7&id=EJ831639"><span>Pendulum Motion and Differential <span class="hlt">Equations</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Reid, Thomas F.; King, Stephen C.</p> <p>2009-01-01</p> <p>A common example of real-world motion that can be modeled by a differential <span class="hlt">equation</span>, and one easily understood by the student, is the simple pendulum. Simplifying assumptions are necessary for closed-form solutions to exist, and frequently there is little discussion of the impact if those assumptions are not met. This article presents a…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5710156','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5710156"><span>Lithium <span class="hlt">equation</span>-of-state</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Blink, J.A.</p> <p>1983-09-01</p> <p>In 1977, Dave Young published an <span class="hlt">equation</span>-of-state (EOS) for lithium. This EOS was used by Lew Glenn in his AFTON calculations of the HYLIFE inertial-fusion-reactor hydrodynamics. In this paper, I summarize Young's development of the EOS and demonstrate a computer program (MATHSY) that plots isotherms, isentropes and constant energy lines on a P-V diagram.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=symbolism&pg=2&id=EJ749932','ERIC'); return false;" href="http://eric.ed.gov/?q=symbolism&pg=2&id=EJ749932"><span>The Symbolism Of Chemical <span class="hlt">Equations</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Jensen, William B.</p> <p>2005-01-01</p> <p>A question about the historical origin of equal sign and double arrow symbolism in balanced chemical <span class="hlt">equation</span> is raised. The study shows that Marshall proposed the symbolism in 1902, which includes the use of currently favored double barb for equilibrium reactions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/EJ250344.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/EJ250344.pdf"><span>Differential <span class="hlt">Equations</span> via Population Dynamics.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Sofo, Anthony</p> <p>1981-01-01</p> <p>Some single species and two species interactions in population models are presented to show how credible examples can be used to teach an underlying, common mathematical structure within apparently different concepts. The models examined consist of differential <span class="hlt">equations</span>, and focus on real-world issues. (MP)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=Symbolism&pg=3&id=EJ749932','ERIC'); return false;" href="https://eric.ed.gov/?q=Symbolism&pg=3&id=EJ749932"><span>The Symbolism Of Chemical <span class="hlt">Equations</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Jensen, William B.</p> <p>2005-01-01</p> <p>A question about the historical origin of equal sign and double arrow symbolism in balanced chemical <span class="hlt">equation</span> is raised. The study shows that Marshall proposed the symbolism in 1902, which includes the use of currently favored double barb for equilibrium reactions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27586766','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27586766"><span>Sonar <span class="hlt">equations</span> for planetary exploration.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ainslie, Michael A; Leighton, Timothy G</p> <p>2016-08-01</p> <p>The set of formulations commonly known as "the sonar <span class="hlt">equations</span>" have for many decades been used to quantify the performance of sonar systems in terms of their ability to detect and localize objects submerged in seawater. The efficacy of the sonar <span class="hlt">equations</span>, with individual terms evaluated in decibels, is well established in Earth's oceans. The sonar <span class="hlt">equations</span> have been used in the past for missions to other planets and moons in the solar system, for which they are shown to be less suitable. While it would be preferable to undertake high-fidelity acoustical calculations to support planning, execution, and interpretation of acoustic data from planetary probes, to avoid possible errors for planned missions to such extraterrestrial bodies in future, doing so requires awareness of the pitfalls pointed out in this paper. There is a need to reexamine the assumptions, practices, and calibrations that work well for Earth to ensure that the sonar <span class="hlt">equations</span> can be accurately applied in combination with the decibel to extraterrestrial scenarios. Examples are given for icy oceans such as exist on Europa and Ganymede, Titan's hydrocarbon lakes, and for the gaseous atmospheres of (for example) Jupiter and Venus.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19720016564','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19720016564"><span>Optimized solution of Kepler's <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kohout, J. M.; Layton, L.</p> <p>1972-01-01</p> <p>A detailed description is presented of KEPLER, an IBM 360 computer program used for the solution of Kepler's <span class="hlt">equation</span> for eccentric anomaly. The program KEPLER employs a second-order Newton-Raphson differential correction process, and it is faster than previously developed programs by an order of magnitude.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ZaMP...67..135H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ZaMP...67..135H"><span>On abstract degenerate neutral differential <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hernández, Eduardo; O'Regan, Donal</p> <p>2016-10-01</p> <p>We introduce a new abstract model of functional differential <span class="hlt">equations</span>, which we call abstract degenerate neutral differential <span class="hlt">equations</span>, and we study the existence of strict solutions. The class of problems and the technical approach introduced in this paper allow us to generalize and extend recent results on abstract neutral differential <span class="hlt">equations</span>. Some examples on nonlinear partial neutral differential <span class="hlt">equations</span> are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=direct-writing&pg=3&id=ED262084','ERIC'); return false;" href="http://eric.ed.gov/?q=direct-writing&pg=3&id=ED262084"><span>Statistical <span class="hlt">Equating</span> of Direct Writing Assessment.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Phillips, Gary W.</p> <p></p> <p>This paper provides empirical data on two approaches to statistically <span class="hlt">equate</span> scores derived from the direct assessment of writing. These methods are linear <span class="hlt">equating</span> and <span class="hlt">equating</span> based on the general polychotomous form of the Rasch model. Data from the Maryland Functional Writing Test are used to <span class="hlt">equate</span> scores obtained from two prompts given in…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=quantum&pg=5&id=EJ985449','ERIC'); return false;" href="http://eric.ed.gov/?q=quantum&pg=5&id=EJ985449"><span>Simple Derivation of the Lindblad <span class="hlt">Equation</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Pearle, Philip</p> <p>2012-01-01</p> <p>The Lindblad <span class="hlt">equation</span> is an evolution <span class="hlt">equation</span> for the density matrix in quantum theory. It is the general linear, Markovian, form which ensures that the density matrix is Hermitian, trace 1, positive and completely positive. Some elementary examples of the Lindblad <span class="hlt">equation</span> are given. The derivation of the Lindblad <span class="hlt">equation</span> presented here is…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=bayesian&pg=4&id=EJ839749','ERIC'); return false;" href="https://eric.ed.gov/?q=bayesian&pg=4&id=EJ839749"><span>A Bayesian Nonparametric Approach to Test <span class="hlt">Equating</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Karabatsos, George; Walker, Stephen G.</p> <p>2009-01-01</p> <p>A Bayesian nonparametric model is introduced for score <span class="hlt">equating</span>. It is applicable to all major <span class="hlt">equating</span> designs, and has advantages over previous <span class="hlt">equating</span> models. Unlike the previous models, the Bayesian model accounts for positive dependence between distributions of scores from two tests. The Bayesian model and the previous <span class="hlt">equating</span> models are…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED382644.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED382644.pdf"><span>Simulated <span class="hlt">Equating</span> Using Several Item Response Curves.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Boldt, R. F.</p> <p></p> <p>The comparison of item response theory models for the Test of English as a Foreign Language (TOEFL) was extended to an <span class="hlt">equating</span> context as simulation trials were used to "<span class="hlt">equate</span> the test to itself." <span class="hlt">Equating</span> sample data were generated from administration of identical item sets. <span class="hlt">Equatings</span> that used procedures based on each model (simple…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=bayesian&pg=3&id=EJ839749','ERIC'); return false;" href="http://eric.ed.gov/?q=bayesian&pg=3&id=EJ839749"><span>A Bayesian Nonparametric Approach to Test <span class="hlt">Equating</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Karabatsos, George; Walker, Stephen G.</p> <p>2009-01-01</p> <p>A Bayesian nonparametric model is introduced for score <span class="hlt">equating</span>. It is applicable to all major <span class="hlt">equating</span> designs, and has advantages over previous <span class="hlt">equating</span> models. Unlike the previous models, the Bayesian model accounts for positive dependence between distributions of scores from two tests. The Bayesian model and the previous <span class="hlt">equating</span> models are…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=quantum&pg=6&id=EJ985449','ERIC'); return false;" href="https://eric.ed.gov/?q=quantum&pg=6&id=EJ985449"><span>Simple Derivation of the Lindblad <span class="hlt">Equation</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Pearle, Philip</p> <p>2012-01-01</p> <p>The Lindblad <span class="hlt">equation</span> is an evolution <span class="hlt">equation</span> for the density matrix in quantum theory. It is the general linear, Markovian, form which ensures that the density matrix is Hermitian, trace 1, positive and completely positive. Some elementary examples of the Lindblad <span class="hlt">equation</span> are given. The derivation of the Lindblad <span class="hlt">equation</span> presented here is…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED572625.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED572625.pdf"><span>The Complexity of One-Step <span class="hlt">Equations</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Ngu, Bing</p> <p>2014-01-01</p> <p>An analysis of one-step <span class="hlt">equations</span> from a cognitive load theory perspective uncovers variation within one-step <span class="hlt">equations</span>. The complexity of one-step <span class="hlt">equations</span> arises from the element interactivity across the operational and relational lines. The higher the number of operational and relational lines, the greater the complexity of the <span class="hlt">equations</span>.…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21550034','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21550034"><span>Relativistic <span class="hlt">equations</span> with fractional and pseudodifferential operators</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Babusci, D.; Dattoli, G.; Quattromini, M.</p> <p>2011-06-15</p> <p>In this paper we use different techniques from the fractional and pseudo-operators calculus to solve partial differential <span class="hlt">equations</span> involving operators with noninteger exponents. We apply the method to <span class="hlt">equations</span> resembling generalizations of the heat <span class="hlt">equations</span> and discuss the possibility of extending the procedure to the relativistic Schroedinger and Dirac <span class="hlt">equations</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11736050','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11736050"><span>Interplays between Harper and Mathieu <span class="hlt">equations</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Papp, E; Micu, C</p> <p>2001-11-01</p> <p>This paper deals with the application of relationships between Harper and Mathieu <span class="hlt">equations</span> to the derivation of energy formulas. Establishing suitable matching conditions, one proceeds by inserting a concrete solution to the Mathieu <span class="hlt">equation</span> into the Harper <span class="hlt">equation</span>. For this purpose, one resorts to the nonlinear oscillations characterizing the Mathieu <span class="hlt">equation</span>. This leads to the derivation of two kinds of energy formulas working in terms of cubic and quadratic algebraic <span class="hlt">equations</span>, respectively. Combining such results yields quadratic <span class="hlt">equations</span> to the energy description of the Harper <span class="hlt">equation</span>, incorporating all parameters needed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvE..91a3309Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvE..91a3309Z"><span>Lattice Boltzmann <span class="hlt">equation</span> method for the Cahn-Hilliard <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zheng, Lin; Zheng, Song; Zhai, Qinglan</p> <p>2015-01-01</p> <p>In this paper a lattice Boltzmann <span class="hlt">equation</span> (LBE) method is designed that is different from the previous LBE for the Cahn-Hilliard <span class="hlt">equation</span> (CHE). The starting point of the present CHE LBE model is from the kinetic theory and the work of Lee and Liu [T. Lee and L. Liu, J. Comput. Phys. 229, 8045 (2010), 10.1016/j.jcp.2010.07.007]; however, because the CHE does not conserve the mass locally, a modified equilibrium density distribution function is introduced to treat the diffusion term in the CHE. Numerical simulations including layered Poiseuille flow, static droplet, and Rayleigh-Taylor instability have been conducted to validate the model. The results show that the predictions of the present LBE agree well with the analytical solution and other numerical results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001PhDT.......177P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001PhDT.......177P"><span>Accurate response surface approximations for weight <span class="hlt">equations</span> based on structural optimization</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Papila, Melih</p> <p></p> <p>Accurate weight prediction methods are vitally important for aircraft design optimization. Therefore, designers seek weight prediction techniques with low computational cost and high accuracy, and usually require a compromise between the two. The compromise can be achieved by combining stress analysis and response surface (RS) methodology. While stress analysis provides accurate weight information, RS techniques help to transmit effectively this information to the optimization procedure. The focus of this dissertation is structural weight <span class="hlt">equations</span> in the form of RS approximations and their accuracy when fitted to results of structural optimizations that are based on finite element analyses. Use of RS methodology filters out the numerical noise in structural optimization results and provides a smooth weight function that can easily be used in gradient-based configuration optimization. In engineering applications RS approximations of low order polynomials are widely used, but the weight may not be modeled well by low-order polynomials, leading to bias errors. In addition, some structural optimization results may have high-amplitude errors (outliers) that may severely affect the accuracy of the weight <span class="hlt">equation</span>. Statistical techniques associated with RS methodology are sought in order to deal with these two difficulties: (1) high-amplitude numerical noise (outliers) and (2) approximation model <span class="hlt">inadequacy</span>. The investigation starts with reducing approximation error by identifying and repairing outliers. A potential reason for outliers in optimization results is premature convergence, and outliers of such nature may be corrected by employing different convergence settings. It is demonstrated that outlier repair can lead to accuracy improvements over the more standard approach of removing outliers. The adequacy of approximation is then studied by a modified lack-of-fit approach, and RS errors due to the approximation model are reduced by using higher order polynomials. In</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19890000291&hterms=equation+state&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dequation%2Bof%2Bstate','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19890000291&hterms=equation+state&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dequation%2Bof%2Bstate"><span>Isothermal <span class="hlt">Equation</span> Of State For Compressed Solids</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vinet, Pascal; Ferrante, John</p> <p>1989-01-01</p> <p>Same <span class="hlt">equation</span> with three adjustable parameters applies to different materials. Improved <span class="hlt">equation</span> of state describes pressure on solid as function of relative volume at constant temperature. Even though types of interatomic interactions differ from one substance to another, form of <span class="hlt">equation</span> determined primarily by overlap of electron wave functions during compression. Consequently, <span class="hlt">equation</span> universal in sense it applies to variety of substances, including ionic, metallic, covalent, and rare-gas solids. Only three parameters needed to describe <span class="hlt">equation</span> for given material.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19890000291&hterms=covalent+ionic&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dcovalent%2Bionic','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19890000291&hterms=covalent+ionic&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dcovalent%2Bionic"><span>Isothermal <span class="hlt">Equation</span> Of State For Compressed Solids</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vinet, Pascal; Ferrante, John</p> <p>1989-01-01</p> <p>Same <span class="hlt">equation</span> with three adjustable parameters applies to different materials. Improved <span class="hlt">equation</span> of state describes pressure on solid as function of relative volume at constant temperature. Even though types of interatomic interactions differ from one substance to another, form of <span class="hlt">equation</span> determined primarily by overlap of electron wave functions during compression. Consequently, <span class="hlt">equation</span> universal in sense it applies to variety of substances, including ionic, metallic, covalent, and rare-gas solids. Only three parameters needed to describe <span class="hlt">equation</span> for given material.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830021442','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830021442"><span>Applications of film thickness <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hamrock, B. J.; Dowson, D.</p> <p>1983-01-01</p> <p>A number of applications of elastohydrodynamic film thickness expressions were considered. The motion of a steel ball over steel surfaces presenting varying degrees of conformity was examined. The <span class="hlt">equation</span> for minimum film thickness in elliptical conjunctions under elastohydrodynamic conditions was applied to roller and ball bearings. An involute gear was also introduced, it was again found that the elliptical conjunction expression yielded a conservative estimate of the minimum film thickness. Continuously variable-speed drives like the Perbury gear, which present truly elliptical elastohydrodynamic conjunctions, are favored increasingly in mobile and static machinery. A representative elastohydrodynamic condition for this class of machinery is considered for power transmission equipment. The possibility of elastohydrodynamic films of water or oil forming between locomotive wheels and rails is examined. The important subject of traction on the railways is attracting considerable attention in various countries at the present time. The final example of a synovial joint introduced the <span class="hlt">equation</span> developed for isoviscous-elastic regimes of lubrication.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhRvD..85j4048L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhRvD..85j4048L"><span>Graviton corrections to Maxwell's <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leonard, Katie E.; Woodard, R. P.</p> <p>2012-05-01</p> <p>We use dimensional regularization to compute the one loop quantum gravitational contribution to the vacuum polarization on flat space background. Adding the appropriate Bogoliubov-Parsiuk-Hepp-Zimmermann counterterm gives a fully renormalized result which we employ to quantum correct Maxwell’s <span class="hlt">equations</span>. These <span class="hlt">equations</span> are solved to show that dynamical photons are unchanged, provided the free state wave functional is appropriately corrected. The response to the instantaneous appearance of a point dipole reveals a perturbative version of the long-conjectured, “smearing of the light cone”. There is no change in the far radiation field produced by an alternating dipole. However, the correction to the static electric field of a point charge shows strengthening at short distances, in contrast to expectations based on the renormalization group. We check for gauge dependence by working out the vacuum polarization in a general 3-parameter family of covariant gauges.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008APS..MAR.P8015L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008APS..MAR.P8015L"><span>A thermodynamic <span class="hlt">equation</span> of jamming</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lu, Kevin; Pirouz Kavehpour, H.</p> <p>2008-03-01</p> <p>Materials ranging from sand to fire-retardant to toothpaste are considered fragile, able to exhibit both solid and fluid-like properties across the jamming transition. Guided by granular flow experiments, our <span class="hlt">equation</span> of jammed states is path-dependent, definable at different athermal equilibrium states. The non-equilibrium thermodynamics based on a structural temperature incorporate physical ageing to address the non-exponential, non-Arrhenious relaxation of granular flows. In short, jamming is simply viewed as a thermodynamic transition that occurs to preserve a positive configurational entropy above absolute zero. Without any free parameters, the proposed <span class="hlt">equation</span>-of-state governs the mechanism of shear-banding and the associated features of shear-softening and thickness-invariance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..MARS22006K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..MARS22006K"><span>Implementing Parquet <span class="hlt">equations</span> using HPX</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kellar, Samuel; Wagle, Bibek; Yang, Shuxiang; Tam, Ka-Ming; Kaiser, Hartmut; Moreno, Juana; Jarrell, Mark</p> <p></p> <p>A new C++ runtime system (HPX) enables simulations of complex systems to run more efficiently on parallel and heterogeneous systems. This increased efficiency allows for solutions to larger simulations of the parquet approximation for a system with impurities. The relevancy of the parquet <span class="hlt">equations</span> depends upon the ability to solve systems which require long runs and large amounts of memory. These limitations, in addition to numerical complications arising from stability of the solutions, necessitate running on large distributed systems. As the computational resources trend towards the exascale and the limitations arising from computational resources vanish efficiency of large scale simulations becomes a focus. HPX facilitates efficient simulations through intelligent overlapping of computation and communication. Simulations such as the parquet <span class="hlt">equations</span> which require the transfer of large amounts of data should benefit from HPX implementations. Supported by the the NSF EPSCoR Cooperative Agreement No. EPS-1003897 with additional support from the Louisiana Board of Regents.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013cpgt.book...59S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013cpgt.book...59S"><span>Systems of Inhomogeneous Linear <span class="hlt">Equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Scherer, Philipp O. J.</p> <p></p> <p>Many problems in physics and especially computational physics involve systems of linear <span class="hlt">equations</span> which arise e.g. from linearization of a general nonlinear problem or from discretization of differential <span class="hlt">equations</span>. If the dimension of the system is not too large standard methods like Gaussian elimination or QR decomposition are sufficient. Systems with a tridiagonal matrix are important for cubic spline interpolation and numerical second derivatives. They can be solved very efficiently with a specialized Gaussian elimination method. Practical applications often involve very large dimensions and require iterative methods. Convergence of Jacobi and Gauss-Seidel methods is slow and can be improved by relaxation or over-relaxation. An alternative for large systems is the method of conjugate gradients.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19750048365&hterms=Spiegel&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DSpiegel','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19750048365&hterms=Spiegel&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DSpiegel"><span>Modal <span class="hlt">equations</span> for cellular convection</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gough, D. O.; Spiegel, E. A.; Toomre, J.</p> <p>1975-01-01</p> <p>We expand the fluctuating flow variables of Boussinesq convection in the planform functions of linear theory. Our proposal is to consider a drastic truncation of this expansion as a possible useful approximation scheme for studying cellular convection. With just one term included, we obtain a fairly simple set of <span class="hlt">equations</span> which reproduces some of the qualitative properties of cellular convection and whose steady-state form has already been derived by Roberts (1966). This set of 'modal <span class="hlt">equations</span>' is analyzed at slightly supercritical and at very high Rayleigh numbers. In the latter regime the Nusselt number varies with Rayleigh number just as in the mean-field approximation with one horizontal scale when the boundaries are rigid. However, the Nusselt number now depends also on the Prandtl number in a way that seems compatible with experiment. The chief difficulty with the approach is the absence of a deductive scheme for deciding which planforms should be retained in the truncated expansion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008EPJB...65..295M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008EPJB...65..295M"><span>Renewal <span class="hlt">equations</span> for option pricing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Montero, M.</p> <p>2008-09-01</p> <p>In this paper we will develop a methodology for obtaining pricing expressions for financial instruments whose underlying asset can be described through a simple continuous-time random walk (CTRW) market model. Our approach is very natural to the issue because it is based in the use of renewal <span class="hlt">equations</span>, and therefore it enhances the potential use of CTRW techniques in finance. We solve these <span class="hlt">equations</span> for typical contract specifications, in a particular but exemplifying case. We also show how a formal general solution can be found for more exotic derivatives, and we compare prices for alternative models of the underlying. Finally, we recover the celebrated results for the Wiener process under certain limits.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12059300','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12059300"><span>Linear superposition in nonlinear <span class="hlt">equations</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Khare, Avinash; Sukhatme, Uday</p> <p>2002-06-17</p> <p>Several nonlinear systems such as the Korteweg-de Vries (KdV) and modified KdV <span class="hlt">equations</span> and lambda phi(4) theory possess periodic traveling wave solutions involving Jacobi elliptic functions. We show that suitable linear combinations of these known periodic solutions yield many additional solutions with different periods and velocities. This linear superposition procedure works by virtue of some remarkable new identities involving elliptic functions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15558698','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15558698"><span>Linear <span class="hlt">equations</span> with random variables.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tango, Toshiro</p> <p>2005-10-30</p> <p>A system of linear <span class="hlt">equations</span> is presented where the unknowns are unobserved values of random variables. A maximum likelihood estimator assuming a multivariate normal distribution and a non-parametric proportional allotment estimator are proposed for the unobserved values of the random variables and for their means. Both estimators can be computed by simple iterative procedures and are shown to perform similarly. The methods are illustrated with data from a national nutrition survey in Japan.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Fract..2450028S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Fract..2450028S"><span>Langevin <span class="hlt">Equation</span> on Fractal Curves</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Satin, Seema; Gangal, A. D.</p> <p>2016-07-01</p> <p>We analyze random motion of a particle on a fractal curve, using Langevin approach. This involves defining a new velocity in terms of mass of the fractal curve, as defined in recent work. The geometry of the fractal curve, plays an important role in this analysis. A Langevin <span class="hlt">equation</span> with a particular model of noise is proposed and solved using techniques of the Fα-Calculus.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995PhRvD..52.5141O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995PhRvD..52.5141O"><span>Instantaneous Bethe-Salpeter <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Olsson, M. G.; Veseli, Siniša.; Williams, Ken</p> <p>1995-11-01</p> <p>We present a systematic algebraic and numerical investigation of the instantaneous Beth-Salpeter <span class="hlt">equation</span>. Emphasis is placed on confining interaction kernels of the Lorentz scalar, time component vector, and full vector-types. We explore the stability of the solutions and Regge behavior for each of these interactions, and conclude that only time component vector confinement leads to normal Regge structure and stable solutions for all quark masses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1214628','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1214628"><span><span class="hlt">Equation</span> of State Project Overview</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Crockett, Scott</p> <p>2015-09-11</p> <p>A general overview of the <span class="hlt">Equation</span> of State (EOS) Project will be presented. The goal is to provide the audience with an introduction of what our more advanced methods entail (DFT, QMD, etc.. ) and how these models are being utilized to better constrain the thermodynamic models. These models substantially reduce our regions of interpolation between the various thermodynamic limits. I will also present a variety example of recent EOS work.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19990047906','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990047906"><span>The Thin Oil Film <span class="hlt">Equation</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brown, James L.; Naughton, Jonathan W.</p> <p>1999-01-01</p> <p>A thin film of oil on a surface responds primarily to the wall shear stress generated on that surface by a three-dimensional flow. The oil film is also subject to wall pressure gradients, surface tension effects and gravity. The partial differential <span class="hlt">equation</span> governing the oil film flow is shown to be related to Burgers' <span class="hlt">equation</span>. Analytical and numerical methods for solving the thin oil film <span class="hlt">equation</span> are presented. A direct numerical solver is developed where the wall shear stress variation on the surface is known and which solves for the oil film thickness spatial and time variation on the surface. An inverse numerical solver is also developed where the oil film thickness spatial variation over the surface at two discrete times is known and which solves for the wall shear stress variation over the test surface. A One-Time-Level inverse solver is also demonstrated. The inverse numerical solver provides a mathematically rigorous basis for an improved form of a wall shear stress instrument suitable for application to complex three-dimensional flows. To demonstrate the complexity of flows for which these oil film methods are now suitable, extensive examination is accomplished for these analytical and numerical methods as applied to a thin oil film in the vicinity of a three-dimensional saddle of separation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015CMaPh.337.1317K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015CMaPh.337.1317K"><span>Nonlocal <span class="hlt">Equations</span> with Measure Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kuusi, Tuomo; Mingione, Giuseppe; Sire, Yannick</p> <p>2015-08-01</p> <p>We develop an existence, regularity and potential theory for nonlinear integrodifferential <span class="hlt">equations</span> involving measure data. The nonlocal elliptic operators considered are possibly degenerate and cover the case of the fractional p-Laplacean operator with measurable coefficients. We introduce a natural function class where we solve the Dirichlet problem, and prove basic and optimal nonlinear Wolff potential estimates for solutions. These are the exact analogs of the results valid in the case of local quasilinear degenerate <span class="hlt">equations</span> established by Boccardo and Gallouët (J Funct Anal 87:149-169, 1989, Partial Differ Equ 17:641-655, 1992) and Kilpeläinen and Malý (Ann Scuola Norm Sup Pisa Cl Sci (IV) 19:591-613, 1992, Acta Math 172:137-161, 1994). As a consequence, we establish a number of results that can be considered as basic building blocks for a nonlocal, nonlinear potential theory: fine properties of solutions, Calderón-Zygmund estimates, continuity and boundedness criteria are established via Wolff potentials. A main tool is the introduction of a global excess functional that allows us to prove a nonlocal analog of the classical theory due to Campanato (Ann Mat Pura Appl (IV) 69:321-381, 1965). Our results cover the case of linear nonlocal <span class="hlt">equations</span> with measurable coefficients, and the one of the fractional Laplacean, and are new already in such cases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22308767','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22308767"><span>The complex chemical Langevin <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Schnoerr, David; Sanguinetti, Guido; Grima, Ramon</p> <p>2014-07-14</p> <p>The chemical Langevin <span class="hlt">equation</span> (CLE) is a popular simulation method to probe the stochastic dynamics of chemical systems. The CLE’s main disadvantage is its break down in finite time due to the problem of evaluating square roots of negative quantities whenever the molecule numbers become sufficiently small. We show that this issue is not a numerical integration problem, rather in many systems it is intrinsic to all representations of the CLE. Various methods of correcting the CLE have been proposed which avoid its break down. We show that these methods introduce undesirable artefacts in the CLE’s predictions. In particular, for unimolecular systems, these correction methods lead to CLE predictions for the mean concentrations and variance of fluctuations which disagree with those of the chemical master <span class="hlt">equation</span>. We show that, by extending the domain of the CLE to complex space, break down is eliminated, and the CLE’s accuracy for unimolecular systems is restored. Although the molecule numbers are generally complex, we show that the “complex CLE” predicts real-valued quantities for the mean concentrations, the moments of intrinsic noise, power spectra, and first passage times, hence admitting a physical interpretation. It is also shown to provide a more accurate approximation of the chemical master <span class="hlt">equation</span> of simple biochemical circuits involving bimolecular reactions than the various corrected forms of the real-valued CLE, the linear-noise approximation and a commonly used two moment-closure approximation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25027995','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25027995"><span>The complex chemical Langevin <span class="hlt">equation</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Schnoerr, David; Sanguinetti, Guido; Grima, Ramon</p> <p>2014-07-14</p> <p>The chemical Langevin <span class="hlt">equation</span> (CLE) is a popular simulation method to probe the stochastic dynamics of chemical systems. The CLE's main disadvantage is its break down in finite time due to the problem of evaluating square roots of negative quantities whenever the molecule numbers become sufficiently small. We show that this issue is not a numerical integration problem, rather in many systems it is intrinsic to all representations of the CLE. Various methods of correcting the CLE have been proposed which avoid its break down. We show that these methods introduce undesirable artefacts in the CLE's predictions. In particular, for unimolecular systems, these correction methods lead to CLE predictions for the mean concentrations and variance of fluctuations which disagree with those of the chemical master <span class="hlt">equation</span>. We show that, by extending the domain of the CLE to complex space, break down is eliminated, and the CLE's accuracy for unimolecular systems is restored. Although the molecule numbers are generally complex, we show that the "complex CLE" predicts real-valued quantities for the mean concentrations, the moments of intrinsic noise, power spectra, and first passage times, hence admitting a physical interpretation. It is also shown to provide a more accurate approximation of the chemical master <span class="hlt">equation</span> of simple biochemical circuits involving bimolecular reactions than the various corrected forms of the real-valued CLE, the linear-noise approximation and a commonly used two moment-closure approximation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..MAR.V1283S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..MAR.V1283S"><span>Geometric Implications of Maxwell's <span class="hlt">Equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smith, Felix T.</p> <p>2015-03-01</p> <p>Maxwell's synthesis of the varied results of the accumulated knowledge of electricity and magnetism, based largely on the searching insights of Faraday, still provide new issues to explore. A case in point is a well recognized anomaly in the Maxwell <span class="hlt">equations</span>: The laws of electricity and magnetism require two 3-vector and two scalar <span class="hlt">equations</span>, but only six dependent variables are available to be their solutions, the 3-vectors E and B. This leaves an apparent redundancy of two degrees of freedom (J. Rosen, AJP 48, 1071 (1980); Jiang, Wu, Povinelli, J. Comp. Phys. 125, 104 (1996)). The observed self-consistency of the eight <span class="hlt">equations</span> suggests that they contain additional information. This can be sought as a previously unnoticed constraint connecting the space and time variables, r and t. This constraint can be identified. It distorts the otherwise Euclidean 3-space of r with the extremely slight, time dependent curvature k (t) =Rcurv-2 (t) of the 3-space of a hypersphere whose radius has the time dependence dRcurv / dt = +/- c nonrelativistically, or dRcurvLor / dt = +/- ic relativistically. The time dependence is exactly that of the Hubble expansion. Implications of this identification will be explored.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3097485','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3097485"><span>ON THE GENERALISED FANT <span class="hlt">EQUATION</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Howe, M. S.; McGowan, R. S.</p> <p>2011-01-01</p> <p>An analysis is made of the fluid-structure interactions involved in the production of voiced speech. It is usual to avoid time consuming numerical simulations of the aeroacoustics of the vocal tract and glottis by the introduction of Fant’s ‘reduced complexity’ <span class="hlt">equation</span> for the glottis volume velocity Q (G. Fant, Acoustic Theory of Speech Production, Mouton, The Hague 1960). A systematic derivation is given of Fant’s <span class="hlt">equation</span> based on the nominally exact <span class="hlt">equations</span> of aerodynamic sound. This can be done with a degree of approximation that depends only on the accuracy with which the time-varying flow geometry and surface-acoustic boundary conditions can be specified, and replaces Fant’s original ‘lumped element’ heuristic approach. The method determines all of the effective ‘source terms’ governing Q. It is illustrated by consideration of a simplified model of the vocal system involving a self-sustaining single-mass model of the vocal folds, that uses free streamline theory to account for surface friction and flow separation within the glottis. Identification is made of a new source term associated with the unsteady vocal fold drag produced by their oscillatory motion transverse to the mean flow. PMID:21603054</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21205250','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21205250"><span>Five-dimensional monopole <span class="hlt">equation</span> with hedgehog ansatz and Abel's differential <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kihara, Hironobu</p> <p>2008-06-15</p> <p>We consider the generalized monopole in the five-dimensional Euclidean space. A numerical solution with the hedgehog ansatz is studied. The Bogomol'nyi <span class="hlt">equation</span> becomes a second-order autonomous nonlinear differential <span class="hlt">equation</span>. The <span class="hlt">equation</span> can be translated into the Abel's differential <span class="hlt">equation</span> of the second kind and is an algebraic differential <span class="hlt">equation</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JDE...263...26F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JDE...263...26F"><span>Boundedness of solutions of measure differential <span class="hlt">equations</span> and dynamic <span class="hlt">equations</span> on time scales</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Federson, M.; Grau, R.; Mesquita, J. G.; Toon, E.</p> <p>2017-07-01</p> <p>In this paper, we investigate the boundedness results for measure differential <span class="hlt">equations</span>. In order to obtain our results, we use the correspondence between these <span class="hlt">equations</span> and generalized ODEs. Furthermore, we prove our results concerning boundedness of solutions for dynamic <span class="hlt">equations</span> on time scales, using the fact that these <span class="hlt">equations</span> represent a particular case of measure differential <span class="hlt">equations</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/772611','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/772611"><span>ADVANCED WAVE-<span class="hlt">EQUATION</span> MIGRATION</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>L. HUANG; M. C. FEHLER</p> <p>2000-12-01</p> <p>Wave-<span class="hlt">equation</span> migration methods can more accurately account for complex wave phenomena than ray-tracing-based Kirchhoff methods that are based on the high-frequency asymptotic approximation of waves. With steadily increasing speed of massively parallel computers, wave-<span class="hlt">equation</span> migration methods are becoming more and more feasible and attractive for imaging complex 3D structures. We present an overview of several efficient and accurate wave-<span class="hlt">equation</span>-based migration methods that we have recently developed. The methods are implemented in the frequency-space and frequency-wavenumber domains and hence they are called dual-domain methods. In the methods, we make use of different approximate solutions of the scalar-wave <span class="hlt">equation</span> in heterogeneous media to recursively downward continue wavefields. The approximations used within each extrapolation interval include the Born, quasi-Born, and Rytov approximations. In one of our dual-domain methods, we use an optimized expansion of the square-root operator in the one-way wave <span class="hlt">equation</span> to minimize the phase error for a given model. This leads to a globally optimized Fourier finite-difference method that is a hybrid split-step Fourier and finite-difference scheme. Migration examples demonstrate that our dual-domain migration methods provide more accurate images than those obtained using the split-step Fourier scheme. The Born-based, quasi-Born-based, and Rytov-based methods are suitable for imaging complex structures whose lateral variations are moderate, such as the Marmousi model. For this model, the computational cost of the Born-based method is almost the same as the split-step Fourier scheme, while other methods takes approximately 15-50% more computational time. The globally optimized Fourier finite-difference method significantly improves the accuracy of the split-step Fourier method for imaging structures having strong lateral velocity variations, such as the SEG/EAGE salt model, at an approximately 30% greater</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ResPh...5..125A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ResPh...5..125A"><span>Exact solutions to the Benney-Luke <span class="hlt">equation</span> and the Phi-4 <span class="hlt">equations</span> by using modified simple <span class="hlt">equation</span> method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Akter, Jesmin; Ali Akbar, M.</p> <p></p> <p>The modified simple <span class="hlt">equation</span> (MSE) method is a competent and highly effective mathematical tool for extracting exact traveling wave solutions to nonlinear evolution <span class="hlt">equations</span> (NLEEs) arising in science, engineering and mathematical physics. In this article, we implement the MSE method to find the exact solutions involving parameters to NLEEs via the Benney-Luke <span class="hlt">equation</span> and the Phi-4 <span class="hlt">equations</span>. The solitary wave solutions are derived from the exact traveling wave solutions when the parameters receive their special values.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=equations&pg=2&id=EJ865980','ERIC'); return false;" href="http://eric.ed.gov/?q=equations&pg=2&id=EJ865980"><span>On the Inclusion of Difference <span class="hlt">Equation</span> Problems and Z Transform Methods in Sophomore Differential <span class="hlt">Equation</span> Classes</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Savoye, Philippe</p> <p>2009-01-01</p> <p>In recent years, I started covering difference <span class="hlt">equations</span> and z transform methods in my introductory differential <span class="hlt">equations</span> course. This allowed my students to extend the "classical" methods for (ordinary differential <span class="hlt">equation</span>) ODE's to discrete time problems arising in many applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=differential&pg=3&id=EJ865980','ERIC'); return false;" href="https://eric.ed.gov/?q=differential&pg=3&id=EJ865980"><span>On the Inclusion of Difference <span class="hlt">Equation</span> Problems and Z Transform Methods in Sophomore Differential <span class="hlt">Equation</span> Classes</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Savoye, Philippe</p> <p>2009-01-01</p> <p>In recent years, I started covering difference <span class="hlt">equations</span> and z transform methods in my introductory differential <span class="hlt">equations</span> course. This allowed my students to extend the "classical" methods for (ordinary differential <span class="hlt">equation</span>) ODE's to discrete time problems arising in many applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26602880','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26602880"><span>[Dosing adjustment and renal function: Which <span class="hlt">equation(s</span>)?].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Delanaye, Pierre; Flamant, Martin; Cavalier, Étienne; Guerber, Fabrice; Vallotton, Thomas; Moranne, Olivier; Pottel, Hans; Boffa, Jean-Jacques; Mariat, Christophe</p> <p>2016-02-01</p> <p>While the CKD-EPI (for Chronic Kidney Disease Epidemiology) <span class="hlt">equation</span> is now implemented worldwide, utilization of the Cockcroft formula is still advocated by some physicians for drug dosage adjustment. Justifications for this recommendation are that the Cockcroft formula was preferentially used to determine dose adjustments according to renal function during the development of many drugs, better predicts drugs-related adverse events and decreases the risk of drug overexposure in the elderly. In this opinion paper, we discuss the weaknesses of the rationale supporting the Cockcroft formula and endorse the French HAS (Haute Autorité de santé) recommendation regarding the preferential use of the CKD-EPI <span class="hlt">equation</span>. When glomerular filtration rate (GFR) is estimated in order to adjust drug dosage, the CKD-EPI value should be re-expressed for the individual body surface area (BSA). Given the difficulty to accurately estimate GFR in the elderly and in individuals with extra-normal BSA, we recommend to prescribe in priority monitorable drugs in those populations or to determine their "true" GFR using a direct measurement method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=stratification&pg=7&id=EJ895495','ERIC'); return false;" href="http://eric.ed.gov/?q=stratification&pg=7&id=EJ895495"><span>New <span class="hlt">Equating</span> Methods and Their Relationships with Levine Observed Score Linear <span class="hlt">Equating</span> under the Kernel <span class="hlt">Equating</span> Framework</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Chen, Haiwen; Holland, Paul</p> <p>2010-01-01</p> <p>In this paper, we develop a new curvilinear <span class="hlt">equating</span> for the nonequivalent groups with anchor test (NEAT) design under the assumption of the classical test theory model, that we name curvilinear Levine observed score <span class="hlt">equating</span>. In fact, by applying both the kernel <span class="hlt">equating</span> framework and the mean preserving linear transformation of…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25544787','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25544787"><span>Generalized Ordinary Differential <span class="hlt">Equation</span> Models.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Miao, Hongyu; Wu, Hulin; Xue, Hongqi</p> <p>2014-10-01</p> <p>Existing estimation methods for ordinary differential <span class="hlt">equation</span> (ODE) models are not applicable to discrete data. The generalized ODE (GODE) model is therefore proposed and investigated for the first time. We develop the likelihood-based parameter estimation and inference methods for GODE models. We propose robust computing algorithms and rigorously investigate the asymptotic properties of the proposed estimator by considering both measurement errors and numerical errors in solving ODEs. The simulation study and application of our methods to an influenza viral dynamics study suggest that the proposed methods have a superior performance in terms of accuracy over the existing ODE model estimation approach and the extended smoothing-based (ESB) method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPCM...28m5001M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPCM...28m5001M"><span>Young’s <span class="hlt">equation</span> revisited</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Makkonen, Lasse</p> <p>2016-04-01</p> <p>Young’s construction for a contact angle at a three-phase intersection forms the basis of all fields of science that involve wetting and capillary action. We find compelling evidence from recent experimental results on the deformation of a soft solid at the contact line, and displacement of an elastic wire immersed in a liquid, that Young’s <span class="hlt">equation</span> can only be interpreted by surface energies, and not as a balance of surface tensions. It follows that the a priori variable in finding equilibrium is not the position of the contact line, but the contact angle. This finding provides the explanation for the pinning of a contact line.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12688877','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12688877"><span>Discrete Boltzmann <span class="hlt">equation</span> for microfluidics.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Baoming; Kwok, Daniel Y</p> <p>2003-03-28</p> <p>We propose a discrete Boltzmann model for microfluidics based on the Boltzmann <span class="hlt">equation</span> with external forces using a single relaxation time collision model. Considering the electrostatic interactions in microfluidics systems, we introduce an equilibrium distribution function that differs from the Maxwell-Boltzmann distribution by an exponential factor to represent the action of an external force field. A statistical mechanical approach is applied to derive the equivalent external acceleration force exerting on the lattice particles based on a mean-field approximation, resulting from the electro-static potential energy and intermolecular potential energy between fluid-fluid and fluid-substrate interactions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AmJPh..83..935P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AmJPh..83..935P"><span>Advanced lab on Fresnel <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Petrova-Mayor, Anna; Gimbal, Scott</p> <p>2015-11-01</p> <p>This experimental and theoretical exercise is designed to promote students' understanding of polarization and thin-film coatings for the practical case of a scanning protected-metal coated mirror. We present results obtained with a laboratory scanner and a polarimeter and propose an affordable and student-friendly experimental arrangement for the undergraduate laboratory. This experiment will allow students to apply basic knowledge of the polarization of light and thin-film coatings, develop hands-on skills with the use of phase retarders, apply the Fresnel <span class="hlt">equations</span> for metallic coating with complex index of refraction, and compute the polarization state of the reflected light.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/240383','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/240383"><span>Asymptotics of radial wave <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Morehead, J.J.</p> <p>1995-10-01</p> <p>The Langer modification is an improvement in the WKB analysis of the radial Schroedinger <span class="hlt">equation</span>. We derive a generalization of the Langer modification to any radial operator. For differential operators we write the modified classical symbols explicitly and show that the WKB wavefunctions with the modification have the exact limiting behavior for small radius. Unlike in the Schroedinger case, generally the modified radial analysis is not equivalent to the WKB analysis of the full problem before reduction by the spherical symmetry. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1238605','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1238605"><span>Germanium multiphase <span class="hlt">equation</span> of state</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Crockett, Scott D.; Lorenzi-Venneri, Giulia De; Kress, Joel D.; Rudin, Sven P.</p> <p>2014-05-07</p> <p>A new SESAME multiphase germanium <span class="hlt">equation</span> of state (EOS) has been developed using the best available experimental data and density functional theory (DFT) calculations. The equilibrium EOS includes the Ge I (diamond), the Ge II (β-Sn) and the liquid phases. The foundation of the EOS is based on density functional theory calculations which are used to determine the cold curve and the Debye temperature. Results are compared to Hugoniot data through the solid-solid and solid-liquid transitions. We propose some experiments to better understand the dynamics of this element</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..SHK.V2005C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..SHK.V2005C"><span>Germanium Multiphase <span class="hlt">Equation</span> of State</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crockett, Scott; Kress, Joel; Rudin, Sven; de Lorenzi-Venneri, Giulia</p> <p>2013-06-01</p> <p>A new SESAME multiphase Germanium <span class="hlt">equation</span> of state (EOS) has been developed utilizing the best experimental data and theoretical calculations. The equilibrium EOS includes the GeI (diamond), GeII (beta-Sn) and liquid phases. We will also explore the meta-stable GeIII (tetragonal) phase of germanium. The theoretical calculations used in constraining the EOS are based on quantum molecular dynamics and density functional theory phonon calculations. We propose some physics rich experiments to better understand the dynamics of this element.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1238605-germanium-multiphase-equation-state','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1238605-germanium-multiphase-equation-state"><span>Germanium multiphase <span class="hlt">equation</span> of state</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Crockett, Scott D.; Lorenzi-Venneri, Giulia De; Kress, Joel D.; ...</p> <p>2014-05-07</p> <p>A new SESAME multiphase germanium <span class="hlt">equation</span> of state (EOS) has been developed using the best available experimental data and density functional theory (DFT) calculations. The equilibrium EOS includes the Ge I (diamond), the Ge II (β-Sn) and the liquid phases. The foundation of the EOS is based on density functional theory calculations which are used to determine the cold curve and the Debye temperature. Results are compared to Hugoniot data through the solid-solid and solid-liquid transitions. We propose some experiments to better understand the dynamics of this element</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JPhCS.500c2006C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JPhCS.500c2006C"><span>Germanium multiphase <span class="hlt">equation</span> of state</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crockett, S. D.; De Lorenzi-Venneri, G.; Kress, J. D.; Rudin, S. P.</p> <p>2014-05-01</p> <p>A new SESAME multiphase germanium <span class="hlt">equation</span> of state (EOS) has been developed utilizing the best available experimental data and density functional theory (DFT) calculations. The equilibrium EOS includes the Ge I (diamond), the Ge II (β-Sn) and the liquid phases. The foundation of the EOS is based on density functional theory calculations which are used to determine the cold curve and the Debye temperature. Results are compared to Hugoniot data through the solid-solid and solid-liquid transitions. We propose some experiments to better understand the dynamics of this element.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGP...113..206M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGP...113..206M"><span>On third order integrable vector Hamiltonian <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meshkov, A. G.; Sokolov, V. V.</p> <p>2017-03-01</p> <p>A complete list of third order vector Hamiltonian <span class="hlt">equations</span> with the Hamiltonian operator Dx having an infinite series of higher conservation laws is presented. A new vector integrable <span class="hlt">equation</span> on the sphere is found.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.epa.gov/risk/regional-screening-levels-rsls-equations-may-2016','PESTICIDES'); return false;" href="https://www.epa.gov/risk/regional-screening-levels-rsls-equations-may-2016"><span>Regional Screening Levels (RSLs) - <span class="hlt">Equations</span> (May 2016)</span></a></p> <p><a target="_blank" href="http://www.epa.gov/pesticides/search.htm">EPA Pesticide Factsheets</a></p> <p></p> <p></p> <p>Regional Screening Level RSL <span class="hlt">equations</span> page provides quick access to the <span class="hlt">equations</span> used in the Chemical Risk Assessment preliminary remediation goal PRG risk based concentration RBC and risk calculator for the assessment of human Health.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.epa.gov/risk/regional-screening-levels-rsls-equations-june-2017','PESTICIDES'); return false;" href="https://www.epa.gov/risk/regional-screening-levels-rsls-equations-june-2017"><span>Regional Screening Levels (RSLs) - <span class="hlt">Equations</span> (June 2017 )</span></a></p> <p><a target="_blank" href="http://www.epa.gov/pesticides/search.htm">EPA Pesticide Factsheets</a></p> <p></p> <p></p> <p>Regional Screening Level RSL <span class="hlt">equations</span> page provides quick access to the <span class="hlt">equations</span> used in the Chemical Risk Assessment preliminary remediation goal PRG risk based concentration RBC and risk calculator for the assessment of human Health.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/10130','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/10130"><span>A net volume <span class="hlt">equation</span> for Northeastern Minnesota.</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Gerhard K. Raile</p> <p>1980-01-01</p> <p>Describes a net volume <span class="hlt">equation</span> for northeastern Minnesota developed as part of the 1977 Minnesota Forest Inventory. <span class="hlt">Equation</span> coefficients are presented by species groupings for both cubic foot and board foot volumes for five tree classes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016TMP...188.1172B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016TMP...188.1172B"><span>Bilinear approach to the supersymmetric Gardner <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Babalic, C. N.; Carstea, A. S.</p> <p>2016-08-01</p> <p>We study a supersymmetric version of the Gardner <span class="hlt">equation</span> (both focusing and defocusing) using the superbilinear formalism. This <span class="hlt">equation</span> is new and cannot be obtained from the supersymmetric modified Korteweg-de Vries <span class="hlt">equation</span> with a nonzero boundary condition. We construct supersymmetric solitons and then by passing to the long-wave limit in the focusing case obtain rational nonsingular solutions. We also discuss the supersymmetric version of the defocusing <span class="hlt">equation</span> and the dynamics of its solutions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA344449','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA344449"><span>Systems of Nonlinear Hyperbolic Partial Differential <span class="hlt">Equations</span></span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1997-12-01</p> <p>McKinney) Travelling wave solutions of the modified Korteweg - deVries -Burgers <span class="hlt">Equation</span> . J. Differential <span class="hlt">Equations</span> , 116 (1995), 448-467. 4. (with D.G...SUBTITLE Systems of Nonlinear Hyperbolic Partial Differential <span class="hlt">Equations</span> 6. AUTHOR’S) Michael Shearer PERFORMING ORGANIZATION NAMES(S) AND...DISTRIBUTION CODE 13. ABSTRACT (Maximum 200 words) This project concerns properties of wave propagation in partial differential <span class="hlt">equations</span> that are nonlinear</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1992TMP....92..697S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1992TMP....92..697S"><span>Symmetry algebras of linear differential <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shapovalov, A. V.; Shirokov, I. V.</p> <p>1992-07-01</p> <p>The local symmetries of linear differential <span class="hlt">equations</span> are investigated by means of proven theorems on the structure of the algebra of local symmetries of translationally and dilatationally invariant differential <span class="hlt">equations</span>. For a nonparabolic second-order <span class="hlt">equation</span>, the absence of nontrivial nonlinear local symmetries is proved. This means that the local symmetries reduce to the Lie algebra of linear differential symmetry operators. For the Laplace—Beltrami <span class="hlt">equation</span>, all local symmetries reduce to the enveloping algebra of the algebra of the conformal group.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JDE...263..285C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JDE...263..285C"><span>Periodic solutions of Fokker-Planck <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Feng; Han, Yuecai; Li, Yong; Yang, Xue</p> <p>2017-07-01</p> <p>In this paper, the existence of periodic solutions of Fokker-Planck <span class="hlt">equations</span> is obtained by discussing the existence of periodic solutions in distribution for some stochastic differential <span class="hlt">equations</span>. To prove the existence of periodic solutions in distribution for stochastic differential <span class="hlt">equations</span>, a new criterion analogous to Halanay's criterion is given. Actually, the criterion is similar to a law of large numbers. Based on this criterion, the existence of periodic solutions in distribution for stochastic (functional) differential <span class="hlt">equations</span> is established by Lyapunov's method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21501353','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21501353"><span>Wave <span class="hlt">equation</span> on spherically symmetric Lorentzian metrics</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bokhari, Ashfaque H.; Al-Dweik, Ahmad Y.; Zaman, F. D.; Kara, A. H.; Karim, M.</p> <p>2011-06-15</p> <p>Wave <span class="hlt">equation</span> on a general spherically symmetric spacetime metric is constructed. Noether symmetries of the <span class="hlt">equation</span> in terms of explicit functions of {theta} and {phi} are derived subject to certain differential constraints. By restricting the metric to flat Friedman case the Noether symmetries of the wave <span class="hlt">equation</span> are presented. Invertible transformations are constructed from a specific subalgebra of these Noether symmetries to convert the wave <span class="hlt">equation</span> with variable coefficients to the one with constant coefficients.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100010899','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100010899"><span>Solving <span class="hlt">Equations</span> of Multibody Dynamics</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jain, Abhinandan; Lim, Christopher</p> <p>2007-01-01</p> <p>Darts++ is a computer program for solving the <span class="hlt">equations</span> of motion of a multibody system or of a multibody model of a dynamic system. It is intended especially for use in dynamical simulations performed in designing and analyzing, and developing software for the control of, complex mechanical systems. Darts++ is based on the Spatial-Operator- Algebra formulation for multibody dynamics. This software reads a description of a multibody system from a model data file, then constructs and implements an efficient algorithm that solves the dynamical <span class="hlt">equations</span> of the system. The efficiency and, hence, the computational speed is sufficient to make Darts++ suitable for use in realtime closed-loop simulations. Darts++ features an object-oriented software architecture that enables reconfiguration of system topology at run time; in contrast, in related prior software, system topology is fixed during initialization. Darts++ provides an interface to scripting languages, including Tcl and Python, that enable the user to configure and interact with simulation objects at run time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/542113','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/542113"><span>Non-markovian boltzmann <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kremp, D.; Bonitz, M.; Kraeft, W.D.; Schlanges, M.</p> <p>1997-08-01</p> <p>A quantum kinetic <span class="hlt">equation</span> for strongly interacting particles (generalized binary collision approximation, ladder or T-matrix approximation) is derived in the framework of the density operator technique. In contrast to conventional kinetic theory, which is valid on large time scales as compared to the collision (correlation) time only, our approach retains the full time dependencies, especially also on short time scales. This means retardation and memory effects resulting from the dynamics of binary correlations and initial correlations are included. Furthermore, the resulting kinetic <span class="hlt">equation</span> conserves total energy (the sum of kinetic and potential energy). The second aspect of generalization is the inclusion of many-body effects, such as self-energy, i.e., renormalization of single-particle energies and damping. To this end we introduce an improved closure relation to the Bogolyubov{endash}Born{endash}Green{endash}Kirkwood{endash}Yvon hierarchy. Furthermore, in order to express the collision integrals in terms of familiar scattering quantities (Mo/ller operator, T-matrix), we generalize the methods of quantum scattering theory by the inclusion of medium effects. To illustrate the effects of memory and damping, the results of numerical simulations are presented. {copyright} 1997 Academic Press, Inc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740002093','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740002093"><span>Shaped cassegrain reflector antenna. [design <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rao, B. L. J.</p> <p>1973-01-01</p> <p>Design <span class="hlt">equations</span> are developed to compute the reflector surfaces required to produce uniform illumination on the main reflector of a cassegrain system when the feed pattern is specified. The final <span class="hlt">equations</span> are somewhat simple and straightforward to solve (using a computer) compared to the ones which exist already in the literature. Step by step procedure for solving the design <span class="hlt">equations</span> is discussed in detail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=relative+AND+measurement+AND+error&id=EJ1030020','ERIC'); return false;" href="http://eric.ed.gov/?q=relative+AND+measurement+AND+error&id=EJ1030020"><span>Local Observed-Score Kernel <span class="hlt">Equating</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Wiberg, Marie; van der Linden, Wim J.; von Davier, Alina A.</p> <p>2014-01-01</p> <p>Three local observed-score kernel <span class="hlt">equating</span> methods that integrate methods from the local <span class="hlt">equating</span> and kernel <span class="hlt">equating</span> frameworks are proposed. The new methods were compared with their earlier counterparts with respect to such measures as bias--as defined by Lord's criterion of equity--and percent relative error. The local kernel item response…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=spline&pg=3&id=EJ314651','ERIC'); return false;" href="http://eric.ed.gov/?q=spline&pg=3&id=EJ314651"><span>Effectiveness of Analytic Smoothing in Equipercentile <span class="hlt">Equating</span>.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Kolen, Michael J.</p> <p>1984-01-01</p> <p>An analytic procedure for smoothing in equipercentile <span class="hlt">equating</span> using cubic smoothing splines is described and illustrated. The effectiveness of the procedure is judged by comparing the results from smoothed equipercentile <span class="hlt">equating</span> with those from other <span class="hlt">equating</span> methods using multiple cross-validations for a variety of sample sizes. (Author/JKS)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000CNSNS...5...64Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000CNSNS...5...64Y"><span>Lattice Boltzmann solver of Rossler <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yan, Guangwu; Ruan, Li</p> <p>2000-06-01</p> <p>We proposed a lattice Boltzmann model for the Rossler <span class="hlt">equation</span>. Using a method of multiscales in the lattice Boltzmann model, we get the diffusion reaction as a special case. If the diffusion effect disappeared, we can obtain the lattice Boltzmann solution of the Rossler <span class="hlt">equation</span> on the mesescopic scale. The numerical results show the method can be used to simulate Rossler <span class="hlt">equation</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/EJ1112187.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/EJ1112187.pdf"><span>Students' <span class="hlt">Equation</span> Understanding and Solving in Iran</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Barahmand, Ali; Shahvarani, Ahmad</p> <p>2014-01-01</p> <p>The purpose of the present article is to investigate how 15-year-old Iranian students interpret the concept of <span class="hlt">equation</span>, its solution, and studying the relation between the students' <span class="hlt">equation</span> understanding and solving. Data from two <span class="hlt">equation</span>-solving exercises are reported. Data analysis shows that there is a significant relationship between…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3928957','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3928957"><span>Multi-time <span class="hlt">equations</span>, classical and quantum</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Petrat, Sören; Tumulka, Roderich</p> <p>2014-01-01</p> <p>Multi-time <span class="hlt">equations</span> are evolution <span class="hlt">equations</span> involving several time variables, one for each particle. Such <span class="hlt">equations</span> have been considered for the purpose of making theories manifestly Lorentz invariant. We compare their status and significance in classical and quantum physics. PMID:24711721</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=stocking&pg=7&id=EJ450921','ERIC'); return false;" href="https://eric.ed.gov/?q=stocking&pg=7&id=EJ450921"><span><span class="hlt">Equating</span> Tests under the Graded Response Model.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Baker, Frank B.</p> <p>1992-01-01</p> <p>The procedure of M.L. Stocking and F.M. Lord (1983) for computing <span class="hlt">equating</span> coefficients for tests having dichotomously scored items is extended to the case of graded response items. A system of <span class="hlt">equations</span> for obtaining the <span class="hlt">equating</span> coefficients under the graded response model is derived. (SLD)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED445011.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED445011.pdf"><span>Nonequivalent Group <span class="hlt">Equating</span> via 1-P HGLLM.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Chu, Kwang-lee; Kamata, Akihito</p> <p></p> <p>The quality of nonequivalent group <span class="hlt">equating</span> by the one-parameter hierarchical generalized linear logistic model (1-P HGLLM) was examined by comparing it with: (1) traditional concurrent <span class="hlt">equating</span>; (2) Stocking-Lord's method; and (3) multiple-group concurrent <span class="hlt">equating</span>. Root mean squared errors (RMSEs) for item parameters indicated that there was no…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016FBS....57..265B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016FBS....57..265B"><span>On Fractional Duffin-Kemmer-Petiau <span class="hlt">Equation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bouzid, N.; Merad, M.; Baleanu, D.</p> <p>2016-04-01</p> <p>In this paper we treat a fractional bosonic, scalar and vectorial, time <span class="hlt">equation</span> namely Duffin-Kemmer-Petiau <span class="hlt">Equation</span>. The fractional variational principle was used, the fractional Euler-Lagrange <span class="hlt">equations</span> were presented. The wave functions were determined and expressed in terms of Mittag-Leffler function.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EJPh...38a5602R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EJPh...38a5602R"><span>Are Maxwell's <span class="hlt">equations</span> Lorentz-covariant?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Redžić, D. V.</p> <p>2017-01-01</p> <p>It is stated in many textbooks that Maxwell's <span class="hlt">equations</span> are manifestly covariant when written down in tensorial form. We recall that tensorial form of Maxwell's <span class="hlt">equations</span> does not secure their tensorial contents; they become covariant by postulating certain transformation properties of field functions. That fact should be stressed when teaching about the covariance of Maxwell's <span class="hlt">equations</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/EJ1053715.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/EJ1053715.pdf"><span>On a <span class="hlt">Equation</span> in Finite Algebraically Structures</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Valcan, Dumitru</p> <p>2013-01-01</p> <p>Solving <span class="hlt">equations</span> in finite algebraically structures (semigroups with identity, groups, rings or fields) many times is not easy. Even the professionals can have trouble in such cases. Therefore, in this paper we proposed to solve in the various finite groups or fields, a binomial <span class="hlt">equation</span> of the form (1). We specify that this <span class="hlt">equation</span> has been…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=conditioning&pg=5&id=EJ1027949','ERIC'); return false;" href="http://eric.ed.gov/?q=conditioning&pg=5&id=EJ1027949"><span>More Issues in Observed-Score <span class="hlt">Equating</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>van der Linden, Wim J.</p> <p>2013-01-01</p> <p>This article is a response to the commentaries on the position paper on observed-score <span class="hlt">equating</span> by van der Linden (this issue). The response focuses on the more general issues in these commentaries, such as the nature of the observed scores that are <span class="hlt">equated</span>, the importance of test-theory assumptions in <span class="hlt">equating</span>, the necessity to use multiple…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007CoTPh..47..995Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007CoTPh..47..995Y"><span>Symmetry Breaking for Black-Scholes <span class="hlt">Equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Xuan-Liu; Zhang, Shun-Li; Qu, Chang-Zheng</p> <p>2007-06-01</p> <p>Black-Scholes <span class="hlt">equation</span> is used to model stock option pricing. In this paper, optimal systems with one to four parameters of Lie point symmetries for Black-Scholes <span class="hlt">equation</span> and its extension are obtained. Their symmetry breaking interaction associated with the optimal systems is also studied. As a result, symmetry reductions and corresponding solutions for the resulting <span class="hlt">equations</span> are obtained.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=3pl+AND+logistics&id=EJ893357','ERIC'); return false;" href="https://eric.ed.gov/?q=3pl+AND+logistics&id=EJ893357"><span>The Effect of Repeaters on <span class="hlt">Equating</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Kim, HeeKyoung; Kolen, Michael J.</p> <p>2010-01-01</p> <p>Test <span class="hlt">equating</span> might be affected by including in the <span class="hlt">equating</span> analyses examinees who have taken the test previously. This study evaluated the effect of including such repeaters on Medical College Admission Test (MCAT) <span class="hlt">equating</span> using a population invariance approach. Three-parameter logistic (3-PL) item response theory (IRT) true score and…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=Cubic+AND+Spline&id=EJ314651','ERIC'); return false;" href="https://eric.ed.gov/?q=Cubic+AND+Spline&id=EJ314651"><span>Effectiveness of Analytic Smoothing in Equipercentile <span class="hlt">Equating</span>.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Kolen, Michael J.</p> <p>1984-01-01</p> <p>An analytic procedure for smoothing in equipercentile <span class="hlt">equating</span> using cubic smoothing splines is described and illustrated. The effectiveness of the procedure is judged by comparing the results from smoothed equipercentile <span class="hlt">equating</span> with those from other <span class="hlt">equating</span> methods using multiple cross-validations for a variety of sample sizes. (Author/JKS)</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Medical+AND+College&pg=5&id=EJ893357','ERIC'); return false;" href="http://eric.ed.gov/?q=Medical+AND+College&pg=5&id=EJ893357"><span>The Effect of Repeaters on <span class="hlt">Equating</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Kim, HeeKyoung; Kolen, Michael J.</p> <p>2010-01-01</p> <p>Test <span class="hlt">equating</span> might be affected by including in the <span class="hlt">equating</span> analyses examinees who have taken the test previously. This study evaluated the effect of including such repeaters on Medical College Admission Test (MCAT) <span class="hlt">equating</span> using a population invariance approach. Three-parameter logistic (3-PL) item response theory (IRT) true score and…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3637690','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3637690"><span>Sparse dynamics for partial differential <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Schaeffer, Hayden; Caflisch, Russel; Hauck, Cory D.; Osher, Stanley</p> <p>2013-01-01</p> <p>We investigate the approximate dynamics of several differential <span class="hlt">equations</span> when the solutions are restricted to a sparse subset of a given basis. The restriction is enforced at every time step by simply applying soft thresholding to the coefficients of the basis approximation. By reducing or compressing the information needed to represent the solution at every step, only the essential dynamics are represented. In many cases, there are natural bases derived from the differential <span class="hlt">equations</span>, which promote sparsity. We find that our method successfully reduces the dynamics of convection <span class="hlt">equations</span>, diffusion <span class="hlt">equations</span>, weak shocks, and vorticity <span class="hlt">equations</span> with high-frequency source terms. PMID:23533273</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JMP....58h1507B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JMP....58h1507B"><span>Linearizability for third order evolution <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Basarab-Horwath, P.; Güngör, F.</p> <p>2017-08-01</p> <p>The problem of linearization for third order evolution <span class="hlt">equations</span> is considered. Criteria for testing <span class="hlt">equations</span> for linearity are presented. A class of linearizable <span class="hlt">equations</span> depending on arbitrary functions is obtained by requiring presence of an infinite-dimensional symmetry group. Linearizing transformations for this class are found using symmetry structure and local conservation laws. A number of special cases as examples are discussed. Their transformation to <span class="hlt">equations</span> within the same class by differential substitutions and connection with KdV and mKdV <span class="hlt">equations</span> is also reviewed in this framework.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1992EM%26P...59..211K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1992EM%26P...59..211K"><span>Poynting-Robertson effect. II - Perturbation <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Klacka, J.</p> <p>1992-12-01</p> <p>The paper addresses the problem of the complete set of perturbation <span class="hlt">equations</span> of celestial mechanics as applied to the Poynting-Robertson effect. Differential <span class="hlt">equations</span> and initial conditions for them are justified. The sudden beginning of the operation of the Poynting-Robertson effect (e.g., sudden release of dust particles from a comet) is taken into account. Two sets of differential <span class="hlt">equations</span> and initial conditions for them are obtained. Both of them are completely equivalent to Newton's <span class="hlt">equation</span> of motion. It is stressed that the transformation mu yields mu(1-beta) must be made in perturbation <span class="hlt">equations</span> of celestial mechanics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015CNSNS..20..674S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015CNSNS..20..674S"><span>Lax integrable nonlinear partial difference <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sahadevan, R.; Nagavigneshwari, G.</p> <p>2015-03-01</p> <p>A systematic investigation to derive nonlinear lattice <span class="hlt">equations</span> governed by partial difference <span class="hlt">equations</span> admitting specific Lax representation is presented. Further whether or not the identified lattice <span class="hlt">equations</span> possess other characteristics of integrability namely Consistency Around the Cube (CAC) property and linearizability through a global transformation is analyzed. Also it is presented that how to derive higher order ordinary difference <span class="hlt">equations</span> or mappings from the obtained lattice <span class="hlt">equations</span> through periodic reduction and investigated whether they are measure preserving or linearizable and admit sufficient number of integrals leading to their integrability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ArRMA.222..731Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ArRMA.222..731Y"><span>Spectrum Analysis of Some Kinetic <span class="hlt">Equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Tong; Yu, Hongjun</p> <p>2016-11-01</p> <p>We analyze the spectrum structure of some kinetic <span class="hlt">equations</span> qualitatively by using semigroup theory and linear operator perturbation theory. The models include the classical Boltzmann <span class="hlt">equation</span> for hard potentials with or without angular cutoff and the Landau <span class="hlt">equation</span> with {γ≥q-2}. As an application, we show that the solutions to these two fundamental <span class="hlt">equations</span> are asymptotically equivalent (mod time decay rate {t^{-5/4}}) as {tto∞} to that of the compressible Navier-Stokes <span class="hlt">equations</span> for initial data around an equilibrium state.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26745463','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26745463"><span>The Specific Analysis of Structural <span class="hlt">Equation</span> Models.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McDonald, Roderick P</p> <p>2004-10-01</p> <p>Conventional structural <span class="hlt">equation</span> modeling fits a covariance structure implied by the <span class="hlt">equations</span> of the model. This treatment of the model often gives misleading results because overall goodness of fit tests do not focus on the specific constraints implied by the model. An alternative treatment arising from Pearl's directed acyclic graph theory checks identifiability and lists and tests the implied constraints. This approach is complete for Markov models, but has remained incomplete for models with correlated disturbances. Some new algebraic results overcome the limitations of DAG theory and give a specific form of structural <span class="hlt">equation</span> analysis that checks identifiability, tests the implied constraints, <span class="hlt">equation</span> by <span class="hlt">equation</span>, and gives consistent estimators of the parameters in closed form from the <span class="hlt">equations</span>. At present the method is limited to recursive models subject to exclusion conditions. With further work, specific structural <span class="hlt">equation</span> modeling may yield a complete alternative to the present, rather unsatisfactory, global covariance structure analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010MeSol..45..712S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010MeSol..45..712S"><span>Bending <span class="hlt">equation</span> for a quasianisotropic plate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shachnev, V. A.</p> <p>2010-10-01</p> <p>In the framework of the linear theory of elasticity, an exact bending <span class="hlt">equation</span> is obtained for the median plane of a plate whose material is a monoclinic system with the axis of symmetry perpendicular to the plate plane. As an example, the <span class="hlt">equation</span> of the median plane of an isotropic plate is considered; the operator of this <span class="hlt">equation</span> coincides with the operator of Sophie Germain's approximate <span class="hlt">equation</span>. As the plate thickness tends to zero, the right-hand side of the <span class="hlt">equation</span> is asymptotically equivalent to the right-hand side of the approximate <span class="hlt">equation</span>. In addition, <span class="hlt">equations</span> relating the median plane transverse stresses and the total stresses in the plate boundary planes to the median plane deflexions are obtained.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhyA..429..103W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhyA..429..103W"><span>Exact solution to fractional logistic <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>West, Bruce J.</p> <p>2015-07-01</p> <p>The logistic <span class="hlt">equation</span> is one of the most familiar nonlinear differential <span class="hlt">equations</span> in the biological and social sciences. Herein we provide an exact solution to an extension of this <span class="hlt">equation</span> to incorporate memory through the use of fractional derivatives in time. The solution to the fractional logistic <span class="hlt">equation</span> (FLE) is obtained using the Carleman embedding technique that allows the nonlinear <span class="hlt">equation</span> to be replaced by an infinite-order set of linear <span class="hlt">equations</span>, which we then solve exactly. The formal series expansion for the initial value solution of the FLE is shown to be expressed in terms of a series of weighted Mittag-Leffler functions that reduces to the well known analytic solution in the limit where the fractional index for the derivative approaches unity. The numerical integration to the FLE provides an excellent fit to the analytic solution. We propose this approach as a general technique for solving a class of nonlinear fractional differential <span class="hlt">equations</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009NewA...14..347B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009NewA...14..347B"><span>The <span class="hlt">equations</span> of medieval cosmology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Buonanno, Roberto; Quercellini, Claudia</p> <p>2009-04-01</p> <p>In Dantean cosmography the Universe is described as a series of concentric spheres with all the known planets embedded in their rotation motion, the Earth located at the centre and Lucifer at the centre of the Earth. Beyond these "celestial spheres", Dante represents the "angelic choirs" as other nine spheres surrounding God. The rotation velocity increases with decreasing distance from God, that is with increasing Power (Virtù). We show that, adding Power as an additional fourth dimension to space, the modern <span class="hlt">equations</span> governing the expansion of a closed Universe (i.e. with the density parameter Ω0 > 1) in the space-time, can be applied to the medieval Universe as imaged by Dante in his Divine Comedy. In this representation, the Cosmos acquires a unique description and Lucifer is not located at the centre of the hyperspheres.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4935996','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4935996"><span>Evolution <span class="hlt">equation</span> for quantum coherence</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hu, Ming-Liang; Fan, Heng</p> <p>2016-01-01</p> <p>The estimation of the decoherence process of an open quantum system is of both theoretical significance and experimental appealing. Practically, the decoherence can be easily estimated if the coherence evolution satisfies some simple relations. We introduce a framework for studying evolution <span class="hlt">equation</span> of coherence. Based on this framework, we prove a simple factorization relation (FR) for the l1 norm of coherence, and identified the sets of quantum channels for which this FR holds. By using this FR, we further determine condition on the transformation matrix of the quantum channel which can support permanently freezing of the l1 norm of coherence. We finally reveal the universality of this FR by showing that it holds for many other related coherence and quantum correlation measures. PMID:27382933</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994JMP....35.5035M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994JMP....35.5035M"><span>Interpolation and partial differential <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maligranda, Lech; Persson, Lars Erik; Wyller, John</p> <p>1994-09-01</p> <p>One of the main motivations for developing the theory of interpolation was to apply it to the theory of partial differential <span class="hlt">equations</span> (PDEs). Nowadays interpolation theory has been developed in an almost unbelievable way {see the bibliography of Maligranda [Interpolation of Operators and Applications (1926-1990), 2nd ed. (Luleå University, Luleå, 1993), p. 154]}. In this article some model examples are presented which display how powerful this theory is when dealing with PDEs. One main aim is to point out when it suffices to use classical interpolation theory and also to give concrete examples of situations when nonlinear interpolation theory has to be applied. Some historical remarks are also included and the relations to similar results are pointed out.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1348210','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1348210"><span>An <span class="hlt">equation</span> for behavioral contrast.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Williams, B A; Wixted, J T</p> <p>1986-01-01</p> <p>Pigeons were trained on a three-component multiple schedule in which the rates of reinforcement in the various components were systematically varied. Response rates were described by an <span class="hlt">equation</span> that posits that the response-strengthening effects of reinforcement are inversely related to the context of reinforcement in which it occurs, and that the context is calculated as the weighted average of the various sources of reinforcement in the situation. The quality of fits was comparable to that found with previous quantitative analyses of concurrent schedules, especially for relative response rates, with over 90% of the variance accounted for in every case. As with previous research, reinforcements in the component that was to follow received greater weights in determining the context than did reinforcements in the preceding component. PMID:3950534</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21409730','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21409730"><span>Entropic corrections to Friedmann <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sheykhi, Ahmad</p> <p>2010-05-15</p> <p>Recently, Verlinde discussed that gravity can be understood as an entropic force caused by changes in the information associated with the positions of material bodies. In Verlinde's argument, the area law of the black hole entropy plays a crucial role. However, the entropy-area relation can be modified from the inclusion of quantum effects, motivated from the loop quantum gravity. In this note, by employing this modified entropy-area relation, we derive corrections to Newton's law of gravitation as well as modified Friedmann <span class="hlt">equations</span> by adopting the viewpoint that gravity can be emerged as an entropic force. Our study further supports the universality of the log correction and provides a strong consistency check on Verlinde's model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=spline&id=EJ1027954','ERIC'); return false;" href="http://eric.ed.gov/?q=spline&id=EJ1027954"><span>Adjoined Piecewise Linear Approximations (APLAs) for <span class="hlt">Equating</span>: Accuracy Evaluations of a Postsmoothing <span class="hlt">Equating</span> Method</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Moses, Tim</p> <p>2013-01-01</p> <p>The purpose of this study was to evaluate the use of adjoined and piecewise linear approximations (APLAs) of raw equipercentile <span class="hlt">equating</span> functions as a postsmoothing <span class="hlt">equating</span> method. APLAs are less familiar than other postsmoothing <span class="hlt">equating</span> methods (i.e., cubic splines), but their use has been described in historical <span class="hlt">equating</span> practices of…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=kernel&pg=4&id=EJ819612','ERIC'); return false;" href="http://eric.ed.gov/?q=kernel&pg=4&id=EJ819612"><span>A Comparison of the Kernel <span class="hlt">Equating</span> Method with Traditional <span class="hlt">Equating</span> Methods Using SAT[R] Data</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Liu, Jinghua; Low, Albert C.</p> <p>2008-01-01</p> <p>This study applied kernel <span class="hlt">equating</span> (KE) in two scenarios: <span class="hlt">equating</span> to a very similar population and <span class="hlt">equating</span> to a very different population, referred to as a distant population, using SAT[R] data. The KE results were compared to the results obtained from analogous traditional <span class="hlt">equating</span> methods in both scenarios. The results indicate that KE results…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=Cubic+AND+Spline&id=EJ1027954','ERIC'); return false;" href="https://eric.ed.gov/?q=Cubic+AND+Spline&id=EJ1027954"><span>Adjoined Piecewise Linear Approximations (APLAs) for <span class="hlt">Equating</span>: Accuracy Evaluations of a Postsmoothing <span class="hlt">Equating</span> Method</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Moses, Tim</p> <p>2013-01-01</p> <p>The purpose of this study was to evaluate the use of adjoined and piecewise linear approximations (APLAs) of raw equipercentile <span class="hlt">equating</span> functions as a postsmoothing <span class="hlt">equating</span> method. APLAs are less familiar than other postsmoothing <span class="hlt">equating</span> methods (i.e., cubic splines), but their use has been described in historical <span class="hlt">equating</span> practices of…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4701001','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4701001"><span>Inferring Mathematical <span class="hlt">Equations</span> Using Crowdsourcing</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wasik, Szymon</p> <p>2015-01-01</p> <p>Crowdsourcing, understood as outsourcing work to a large network of people in the form of an open call, has been utilized successfully many times, including a very interesting concept involving the implementation of computer games with the objective of solving a scientific problem by employing users to play a game—so-called crowdsourced serious games. Our main objective was to verify whether such an approach could be successfully applied to the discovery of mathematical <span class="hlt">equations</span> that explain experimental data gathered during the observation of a given dynamic system. Moreover, we wanted to compare it with an approach based on artificial intelligence that uses symbolic regression to find such formulae automatically. To achieve this, we designed and implemented an Internet game in which players attempt to design a spaceship representing an <span class="hlt">equation</span> that models the observed system. The game was designed while considering that it should be easy to use for people without strong mathematical backgrounds. Moreover, we tried to make use of the collective intelligence observed in crowdsourced systems by enabling many players to collaborate on a single solution. The idea was tested on several hundred players playing almost 10,000 games and conducting a user opinion survey. The results prove that the proposed solution has very high potential. The function generated during weeklong tests was almost as precise as the analytical solution of the model of the system and, up to a certain complexity level of the formulae, it explained data better than the solution generated automatically by Eureqa, the leading software application for the implementation of symbolic regression. Moreover, we observed benefits of using crowdsourcing; the chain of consecutive solutions that led to the best solution was obtained by the continuous collaboration of several players. PMID:26713846</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26713846','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26713846"><span>Inferring Mathematical <span class="hlt">Equations</span> Using Crowdsourcing.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wasik, Szymon; Fratczak, Filip; Krzyskow, Jakub; Wulnikowski, Jaroslaw</p> <p>2015-01-01</p> <p>Crowdsourcing, understood as outsourcing work to a large network of people in the form of an open call, has been utilized successfully many times, including a very interesting concept involving the implementation of computer games with the objective of solving a scientific problem by employing users to play a game-so-called crowdsourced serious games. Our main objective was to verify whether such an approach could be successfully applied to the discovery of mathematical <span class="hlt">equations</span> that explain experimental data gathered during the observation of a given dynamic system. Moreover, we wanted to compare it with an approach based on artificial intelligence that uses symbolic regression to find such formulae automatically. To achieve this, we designed and implemented an Internet game in which players attempt to design a spaceship representing an <span class="hlt">equation</span> that models the observed system. The game was designed while considering that it should be easy to use for people without strong mathematical backgrounds. Moreover, we tried to make use of the collective intelligence observed in crowdsourced systems by enabling many players to collaborate on a single solution. The idea was tested on several hundred players playing almost 10,000 games and conducting a user opinion survey. The results prove that the proposed solution has very high potential. The function generated during weeklong tests was almost as precise as the analytical solution of the model of the system and, up to a certain complexity level of the formulae, it explained data better than the solution generated automatically by Eureqa, the leading software application for the implementation of symbolic regression. Moreover, we observed benefits of using crowdsourcing; the chain of consecutive solutions that led to the best solution was obtained by the continuous collaboration of several players.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23509385','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23509385"><span>Complex PT-symmetric nonlinear Schrödinger <span class="hlt">equation</span> and Burgers <span class="hlt">equation</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yan, Zhenya</p> <p>2013-04-28</p> <p>The complex -symmetric nonlinear wave models have drawn much attention in recent years since the complex -symmetric extensions of the Korteweg-de Vries (KdV) <span class="hlt">equation</span> were presented in 2007. In this review, we focus on the study of the complex -symmetric nonlinear Schrödinger <span class="hlt">equation</span> and Burgers <span class="hlt">equation</span>. First of all, we briefly introduce the basic property of complex symmetry. We then report on exact solutions of one- and two-dimensional nonlinear Schrödinger <span class="hlt">equations</span> (known as the Gross-Pitaevskii <span class="hlt">equation</span> in Bose-Einstein condensates) with several complex -symmetric potentials. Finally, some complex -symmetric extension principles are used to generate some complex -symmetric nonlinear wave <span class="hlt">equations</span> starting from both -symmetric (e.g. the KdV <span class="hlt">equation</span>) and non- -symmetric (e.g. the Burgers <span class="hlt">equation</span>) nonlinear wave <span class="hlt">equations</span>. In particular, we discuss exact solutions of some representative ones of the complex -symmetric Burgers <span class="hlt">equation</span> in detail.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014CoTPh..61..203Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014CoTPh..61..203Z"><span>Generation of Nonlinear Evolution <span class="hlt">Equations</span> by Reductions of the Self-Dual Yang—Mills <span class="hlt">Equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Yu-Feng; Hon-Wah, Tam</p> <p>2014-02-01</p> <p>With the help of some reductions of the self-dual Yang Mills (briefly written as sdYM) <span class="hlt">equations</span>, we introduce a Lax pair whose compatibility condition leads to a set of (2 + 1)-dimensional <span class="hlt">equations</span>. Its first reduction gives rise to a generalized variable-coefficient Burgers <span class="hlt">equation</span> with a forced term. Furthermore, the Burgers <span class="hlt">equation</span> again reduces to a forced Burgers <span class="hlt">equation</span> with constant coefficients, the standard Burgers <span class="hlt">equation</span>, the heat <span class="hlt">equation</span>, the Fisher <span class="hlt">equation</span>, and the Huxley <span class="hlt">equation</span>, respectively. The second reduction generates a few new (2 + 1)-dimensional nonlinear integrable systems, in particular, obtains a kind of (2 + 1)-dimensional integrable couplings of a new (2 + 1)-dimensional integrable nonlinear <span class="hlt">equation</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/482311','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/482311"><span>Exact and explicit solitary wave solutions to some nonlinear <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jiefang Zhang</p> <p>1996-08-01</p> <p>Exact and explicit solitary wave solutions are obtained for some physically interesting nonlinear evolutions and wave <span class="hlt">equations</span> in physics and other fields by using a special transformation. These <span class="hlt">equations</span> include the KdV-Burgers <span class="hlt">equation</span>, the MKdV-Burgers <span class="hlt">equation</span>, the combined KdV-MKdV <span class="hlt">equation</span>, the Newell-Whitehead <span class="hlt">equation</span>, the dissipative {Phi}{sup 4}-model <span class="hlt">equation</span>, the generalized Fisher <span class="hlt">equation</span>, and the elastic-medium wave <span class="hlt">equation</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014acm..conf..205H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014acm..conf..205H"><span>Dust levitation about Itokawa's <span class="hlt">equator</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hartzell, C.; Zimmerman, M.; Takahashi, Y.</p> <p>2014-07-01</p> <p> levitation about Itokawa, we must include accurate plasma and gravity models. We use a 2D PIC code (described in [8]) to model the plasma environment about Itokawa's <span class="hlt">equator</span>. The plasma model includes photoemission and shadowing. Thus, we model the plasma environment for various solar incidence angles. The plasma model gives us the 2D electric field components and the plasma potential. We model the gravity field around the equatorial cross-section using an Interior Gravity model [9]. The gravity model is based on the shape model acquired by the Hayabusa mission team and, unlike other models, is quick and accurate close to the surface of the body. Due to the nonspherical shape of Itokawa, the electrostatic force and the gravity may not be collinear. Given our accurate plasma and gravity environments, we are able to simulate the trajectories of dust grains about the <span class="hlt">equator</span> of Itokawa. When modeling the trajectories of the grains, the current to the grains is calculated using Nitter et al.'s formulation [10] with the plasma sheath parameters provided by our PIC model (i.e., the potential minimum, the potential at the surface, and the sheath type). Additionally, we are able to numerically locate the equilibria about which dust grains may levitate. Interestingly, we observe that equilibria exist for grains up to 20 microns in radius about Itokawa's <span class="hlt">equator</span> when the Sun is illuminating Itokawa's 'otter tail'. This grain size is significantly larger than the stably levitating grains we observed using our 1D plasma and gravity models. Conclusions and Future Work: The possibility of dust levitation above asteroids has implications both for our understanding of their evolution and for the design of future missions to these bodies. Using detailed gravity and plasma models, we are above to propagate the trajectories of dust particles about Itokawa's <span class="hlt">equator</span> and identify the equilibria about which these grains will levitate. Using these simulations, we see that grains up to 20 microns</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JPhA...43e5203M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JPhA...43e5203M"><span>A fractional Dirac <span class="hlt">equation</span> and its solution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Muslih, Sami I.; Agrawal, Om P.; Baleanu, Dumitru</p> <p>2010-02-01</p> <p>This paper presents a fractional Dirac <span class="hlt">equation</span> and its solution. The fractional Dirac <span class="hlt">equation</span> may be obtained using a fractional variational principle and a fractional Klein-Gordon <span class="hlt">equation</span>; both methods are considered here. We extend the variational formulations for fractional discrete systems to fractional field systems defined in terms of Caputo derivatives. By applying the variational principle to a fractional action S, we obtain the fractional Euler-Lagrange <span class="hlt">equations</span> of motion. We present a Lagrangian and a Hamiltonian for the fractional Dirac <span class="hlt">equation</span> of order α. We also use a fractional Klein-Gordon <span class="hlt">equation</span> to obtain the fractional Dirac <span class="hlt">equation</span> which is the same as that obtained using the fractional variational principle. Eigensolutions of this <span class="hlt">equation</span> are presented which follow the same approach as that for the solution of the standard Dirac <span class="hlt">equation</span>. We also provide expressions for the path integral quantization for the fractional Dirac field which, in the limit α → 1, approaches to the path integral for the regular Dirac field. It is hoped that the fractional Dirac <span class="hlt">equation</span> and the path integral quantization of the fractional field will allow further development of fractional relativistic quantum mechanics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5733762','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5733762"><span>Remarks on the Kuramoto-Sivashinsky <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Nicolaenko, B.; Scheurer, B.</p> <p>1983-01-01</p> <p>We report here a joint work in progress on the Kuramoto-Sivashinsky <span class="hlt">equation</span>. The question we address is the analytical study of a fourth order nonlinear evolution <span class="hlt">equation</span>. This <span class="hlt">equation</span> has been obtained by Sivashinsky in the context of combustion and independently by Kuramoto in the context of reaction diffusion-systems. Both were motivated by (nonlinear) stability of travelling waves. Numerical calculations have been done on this <span class="hlt">equation</span>. All the results seem to indicate a chaotic behavior of the solution. Therefore, the analytical study is of interest in analogy with the Burger's and Navier-Stokes <span class="hlt">equations</span>. Here we give some existence and uniqueness results for the <span class="hlt">equation</span> in space dimension one, and we also study a fractional step method of numerical resolution. In a forthcoming joint paper with R. Temam, we will study the asymptotic behavior, as t approaches infinity, of the solution of (0.1) and give an estimate on the number of determining modes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21371054','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21371054"><span>Darboux transformation for the NLS <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Aktosun, Tuncay; Mee, Cornelis van der</p> <p>2010-03-08</p> <p>We analyze a certain class of integral <span class="hlt">equations</span> associated with Marchenko <span class="hlt">equations</span> and Gel'fand-Levitan <span class="hlt">equations</span>. Such integral <span class="hlt">equations</span> arise through a Fourier transformation on various ordinary differential <span class="hlt">equations</span> involving a spectral parameter. When the integral operator is perturbed by a finite-rank perturbation, we explicitly evaluate the change in the solution in terms of the unperturbed quantities and the finite-rank perturbation. We show that this result provides a fundamental approach to derive Darboux transformations for various systems of ordinary differential operators. We illustrate our theory by providing the explicit Darboux transformation for the Zakharov-Shabat system and show how the potential and wave function change when a simple discrete eigenvalue is added to the spectrum, and thus we also provide a one-parameter family of Darboux transformations for the nonlinear Schroedinger <span class="hlt">equation</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AIPC.1682e0007G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AIPC.1682e0007G"><span>Stochastic differential <span class="hlt">equation</span> model to Prendiville processes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Granita, Bahar, Arifah</p> <p>2015-10-01</p> <p>The Prendiville process is another variation of the logistic model which assumes linearly decreasing population growth rate. It is a continuous time Markov chain (CTMC) taking integer values in the finite interval. The continuous time Markov chain can be approximated by stochastic differential <span class="hlt">equation</span> (SDE). This paper discusses the stochastic differential <span class="hlt">equation</span> of Prendiville process. The work started with the forward Kolmogorov <span class="hlt">equation</span> in continuous time Markov chain of Prendiville process. Then it was formulated in the form of a central-difference approximation. The approximation was then used in Fokker-Planck <span class="hlt">equation</span> in relation to the stochastic differential <span class="hlt">equation</span> of the Prendiville process. The explicit solution of the Prendiville process was obtained from the stochastic differential <span class="hlt">equation</span>. Therefore, the mean and variance function of the Prendiville process could be easily found from the explicit solution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22492505','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22492505"><span>Stochastic differential <span class="hlt">equation</span> model to Prendiville processes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Granita; Bahar, Arifah</p> <p>2015-10-22</p> <p>The Prendiville process is another variation of the logistic model which assumes linearly decreasing population growth rate. It is a continuous time Markov chain (CTMC) taking integer values in the finite interval. The continuous time Markov chain can be approximated by stochastic differential <span class="hlt">equation</span> (SDE). This paper discusses the stochastic differential <span class="hlt">equation</span> of Prendiville process. The work started with the forward Kolmogorov <span class="hlt">equation</span> in continuous time Markov chain of Prendiville process. Then it was formulated in the form of a central-difference approximation. The approximation was then used in Fokker-Planck <span class="hlt">equation</span> in relation to the stochastic differential <span class="hlt">equation</span> of the Prendiville process. The explicit solution of the Prendiville process was obtained from the stochastic differential <span class="hlt">equation</span>. Therefore, the mean and variance function of the Prendiville process could be easily found from the explicit solution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003JAP....93.8966B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003JAP....93.8966B"><span><span class="hlt">Equation</span> of state of polytetrafluoroethylene</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bourne, N. K.; Gray, G. T.</p> <p>2003-06-01</p> <p>The present drive to make munitions as safe as is feasible and to develop predictive models describing their constitutive response, has led to the development and production of plastic bonded explosives and propellants. There is a range of elastomers used as binder materials with the energetic components. One of these is known as Kel-F-800™ (poly-chloro-trifluroethylene) whose structure is in some ways analogous to that of poly-tetrafluoroethylene (PTFE or Teflon). Thus, it is of interest to assess the mechanical behavior of Teflon and to compare the response of five different production Teflon materials, two of which were produced in pedigree form, one as-received product, and two from previous in-depth literature studies. The <span class="hlt">equations</span> of state of these variants were quantified by conducting a series of shock impact experiments in which both pressure-particle velocity and shock velocity-particle velocity dependencies were measured. The compressive behavior of Teflon, based upon the results of this study, appears to be independent of the production route and additives introduced.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AIPC.1793e0013B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AIPC.1793e0013B"><span>Silicon nitride <span class="hlt">equation</span> of state</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brown, Robert C.; Swaminathan, Pazhayannur K.</p> <p>2017-01-01</p> <p>This report presents the development of a global, multi-phase <span class="hlt">equation</span> of state (EOS) for the ceramic silicon nitride (Si3N4).1 Structural forms include amorphous silicon nitride normally used as a thin film and three crystalline polymorphs. Crystalline phases include hexagonal α-Si3N4, hexagonal β-Si3N4, and the cubic spinel c-Si3N4. Decomposition at about 1900 °C results in a liquid silicon phase and gas phase products such as molecular nitrogen, atomic nitrogen, and atomic silicon. The silicon nitride EOS was developed using EOSPro which is a new and extended version of the PANDA II code. Both codes are valuable tools and have been used successfully for a variety of material classes. Both PANDA II and EOSPro can generate a tabular EOS that can be used in conjunction with hydrocodes. The paper describes the development efforts for the component solid phases and presents results obtained using the EOSPro phase transition model to investigate the solid-solid phase transitions in relation to the available shock data that have indicated a complex and slow time dependent phase change to the c-Si3N4 phase. Furthermore, the EOSPro mixture model is used to develop a model for the decomposition products; however, the need for a kinetic approach is suggested to combine with the single component solid models to simulate and further investigate the global phase coexistences.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..SHK.W1018S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..SHK.W1018S"><span>Silicon Nitride <span class="hlt">Equation</span> of State</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Swaminathan, Pazhayannur; Brown, Robert</p> <p>2015-06-01</p> <p>This report presents the development a global, multi-phase <span class="hlt">equation</span> of state (EOS) for the ceramic silicon nitride (Si3N4) . Structural forms include amorphous silicon nitride normally used as a thin film and three crystalline polymorphs. Crystalline phases include hexagonal α-Si3N4, hexagonalβ-Si3N4, and the cubic spinel c-Si3N4. Decomposition at about 1900 °C results in a liquid silicon phase and gas phase products such as molecular nitrogen, atomic nitrogen, and atomic silicon. The silicon nitride EOS was developed using EOSPro which is a new and extended version of the PANDA II code. Both codes are valuable tools and have been used successfully for a variety of material classes. Both PANDA II and EOSPro can generate a tabular EOS that can be used in conjunction with hydrocodes. The paper describes the development efforts for the component solid phases and presents results obtained using the EOSPro phase transition model to investigate the solid-solid phase transitions in relation to the available shock data. Furthermore, the EOSPro mixture model is used to develop a model for the decomposition products and then combined with the single component solid models to study the global phase diagram. Sponsored by the NASA Goddard Space Flight Center Living With a Star program office.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015CoPhC.197..169E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015CoPhC.197..169E"><span>Solving <span class="hlt">equations</span> through particle dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Edvardsson, S.; Neuman, M.; Edström, P.; Olin, H.</p> <p>2015-12-01</p> <p>The present work evaluates a recently developed particle method (DFPM). The basic idea behind this method is to utilize a Newtonian system of interacting particles that through dissipation solves mathematical problems. We find that this second order dynamical system results in an algorithm that is among the best methods known. The present work studies large systems of linear <span class="hlt">equations</span>. Of special interest is the wide eigenvalue spectrum. This case is common as the discretization of the continuous problem becomes dense. The convergence rate of DFPM is shown to be in parity with that of the conjugate gradient method, both analytically and through numerical examples. However, an advantage with DFPM is that it is cheaper per iteration. Another advantage is that it is not restricted to symmetric matrices only, as is the case for the conjugate gradient method. The convergence properties of DFPM are shown to be superior to the closely related approach utilizing only a first order dynamical system, and also to several other iterative methods in numerical linear algebra. The performance properties are understood and optimized by taking advantage of critically damped oscillators in classical mechanics. Just as in the case of the conjugate gradient method, a limitation is that all eigenvalues (spring constants) are required to be of the same sign. DFPM has no other limitation such as matrix structure or a spectral radius as is common among iterative methods. Examples are provided to test the particle algorithm's merits and also various performance comparisons with existent numerical algorithms are provided.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016WRR....52.1070B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016WRR....52.1070B"><span>Stability analysis of ecomorphodynamic <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bärenbold, F.; Crouzy, B.; Perona, P.</p> <p>2016-02-01</p> <p>In order to shed light on the influence of riverbed vegetation on river morphodynamics, we perform a linear stability analysis on a minimal model of vegetation dynamics coupled with classical one- and two-dimensional Saint-Venant-Exner <span class="hlt">equations</span> of morphodynamics. Vegetation is modeled as a density field of rigid, nonsubmerged cylinders and affects flow via a roughness change. Furthermore, vegetation is assumed to develop following a logistic dependence and may be uprooted by flow. First, we perform the stability analysis of the reduced one-dimensional framework. As a result of the competitive interaction between vegetation growth and removal through uprooting, we find a domain in the parameter space where originally straight rivers are unstable toward periodic longitudinal patterns. For realistic values of the sediment transport parameter, the dominant longitudinal wavelength is determined by the parameters of the vegetation model. Bed topography is found to adjust to the spatial pattern fixed by vegetation. Subsequently, the stability analysis is repeated for the two-dimensional framework, where the system may evolve toward alternate or multiple bars. On a fixed bed, we find instability toward alternate bars due to flow-vegetation interaction, but no multiple bars. Both alternate and multiple bars are present on a movable, vegetated bed. Finally, we find that the addition of vegetation to a previously unvegetated riverbed favors instability toward alternate bars and thus the development of a single course rather than braiding.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/139096','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/139096"><span>LINPACK. Simultaneous Linear Algebraic <span class="hlt">Equations</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Miller, M.A.</p> <p>1990-05-01</p> <p>LINPACK is a collection of FORTRAN subroutines which analyze and solve various classes of systems of simultaneous linear algebraic <span class="hlt">equations</span>. The collection deals with general, banded, symmetric indefinite, symmetric positive definite, triangular, and tridiagonal square matrices, as well as with least squares problems and the QR and singular value decompositions of rectangular matrices. A subroutine-naming convention is employed in which each subroutine name consists of five letters which represent a coded specification (TXXYY) of the computation done by that subroutine. The first letter, T, indicates the matrix data type. Standard FORTRAN allows the use of three such types: S REAL, D DOUBLE PRECISION, and C COMPLEX. In addition, some FORTRAN systems allow a double-precision complex type: Z COMPLEX*16. The second and third letters of the subroutine name, XX, indicate the form of the matrix or its decomposition: GE General, GB General band, PO Positive definite, PP Positive definite packed, PB Positive definite band, SI Symmetric indefinite, SP Symmetric indefinite packed, HI Hermitian indefinite, HP Hermitian indefinite packed, TR Triangular, GT General tridiagonal, PT Positive definite tridiagonal, CH Cholesky decomposition, QR Orthogonal-triangular decomposition, SV Singular value decomposition. The final two letters, YY, indicate the computation done by the particular subroutine: FA Factor, CO Factor and estimate condition, SL Solve, DI Determinant and/or inverse and/or inertia, DC Decompose, UD Update, DD Downdate, EX Exchange. The LINPACK package also includes a set of routines to perform basic vector operations called the Basic Linear Algebra Subprograms (BLAS).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/145553','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/145553"><span>LINPACK. Simultaneous Linear Algebraic <span class="hlt">Equations</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Dongarra, J.J.</p> <p>1982-05-02</p> <p>LINPACK is a collection of FORTRAN subroutines which analyze and solve various classes of systems of simultaneous linear algebraic <span class="hlt">equations</span>. The collection deals with general, banded, symmetric indefinite, symmetric positive definite, triangular, and tridiagonal square matrices, as well as with least squares problems and the QR and singular value decompositions of rectangular matrices. A subroutine-naming convention is employed in which each subroutine name consists of five letters which represent a coded specification (TXXYY) of the computation done by that subroutine. The first letter, T, indicates the matrix data type. Standard FORTRAN allows the use of three such types: S REAL, D DOUBLE PRECISION, and C COMPLEX. In addition, some FORTRAN systems allow a double-precision complex type: Z COMPLEX*16. The second and third letters of the subroutine name, XX, indicate the form of the matrix or its decomposition: GE General, GB General band, PO Positive definite, PP Positive definite packed, PB Positive definite band, SI Symmetric indefinite, SP Symmetric indefinite packed, HI Hermitian indefinite, HP Hermitian indefinite packed, TR Triangular, GT General tridiagonal, PT Positive definite tridiagonal, CH Cholesky decomposition, QR Orthogonal-triangular decomposition, SV Singular value decomposition. The final two letters, YY, indicate the computation done by the particular subroutine: FA Factor, CO Factor and estimate condition, SL Solve, DI Determinant and/or inverse and/or inertia, DC Decompose, UD Update, DD Downdate, EX Exchange. The LINPACK package also includes a set of routines to perform basic vector operations called the Basic Linear Algebra Subprograms (BLAS).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JDE...259.1542C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JDE...259.1542C"><span>Wei-Norman <span class="hlt">equations</span> for classical groups</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Charzyński, Szymon; Kuś, Marek</p> <p>2015-08-01</p> <p>We show that the nonlinear autonomous Wei-Norman <span class="hlt">equations</span>, expressing the solution of a linear system of non-autonomous <span class="hlt">equations</span> on a Lie algebra, can be reduced to the hierarchy of matrix Riccati <span class="hlt">equations</span> in the case of all classical simple Lie algebras. The result generalizes our previous one concerning the complex Lie algebra of the special linear group. We show that it cannot be extended to all simple Lie algebras, in particular to the exceptional G2 algebra.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850010342','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850010342"><span>Chandrasekhar <span class="hlt">equations</span> for infinite dimensional systems</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ito, K.; Powers, R. K.</p> <p>1985-01-01</p> <p>Chandrasekhar <span class="hlt">equations</span> are derived for linear time invariant systems defined on Hilbert spaces using a functional analytic technique. An important consequence of this is that the solution to the evolutional Riccati <span class="hlt">equation</span> is strongly differentiable in time and one can define a strong solution of the Riccati differential <span class="hlt">equation</span>. A detailed discussion on the linear quadratic optimal control problem for hereditary differential systems is also included.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860058247&hterms=Hereditary&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DHereditary','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860058247&hterms=Hereditary&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DHereditary"><span>Chandrasekhar <span class="hlt">equations</span> for infinite dimensional systems</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ito, K.; Powers, R.</p> <p>1985-01-01</p> <p>The existence of Chandrasekhar <span class="hlt">equations</span> for linear time-invariant systems defined on Hilbert spaces is investigated. An important consequence is that the solution to the evolutional Riccati <span class="hlt">equation</span> is strongly differentiable in time, and that a strong solution of the Riccati differential <span class="hlt">equation</span> can be defined. A discussion of the linear-quadratic optimal-control problem for hereditary differential systems is also included.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/279712','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/279712"><span>The Husimi representation and the Vlasov <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>LEplattenier, P.; Suraud, E.; Reinhard, P.G.</p> <p>1995-12-01</p> <p>We investigate the {ital h} expansion of the Time-Dependent Hartree Fock <span class="hlt">equation</span> in the Wigner and Husimi representations. Both lead formally to the Vlasov <span class="hlt">equation</span> in lowest order. The Husimi representation delivers a more stable expansion in particular when the self-interaction in the mean field is considered. The test particle solution of the Vlasov <span class="hlt">equation</span> turns out to be closely related to the Husimi representation. Copyright {copyright} 1995 Academic Press, Inc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1184176','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1184176"><span>The Boltzmann <span class="hlt">equation</span> in the difference formulation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Szoke, Abraham; Brooks III, Eugene D.</p> <p>2015-05-06</p> <p>First we recall the assumptions that are needed for the validity of the Boltzmann <span class="hlt">equation</span> and for the validity of the compressible Euler <span class="hlt">equations</span>. We then present the difference formulation of these <span class="hlt">equations</span> and make a connection with the time-honored Chapman - Enskog expansion. We discuss the hydrodynamic limit and calculate the thermal conductivity of a monatomic gas, using a simplified approximation for the collision term. Our formulation is more consistent and simpler than the traditional derivation.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19830268','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19830268"><span>Discrete Surface Modelling Using Partial Differential <span class="hlt">Equations</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xu, Guoliang; Pan, Qing; Bajaj, Chandrajit L</p> <p>2006-02-01</p> <p>We use various nonlinear partial differential <span class="hlt">equations</span> to efficiently solve several surface modelling problems, including surface blending, N-sided hole filling and free-form surface fitting. The nonlinear <span class="hlt">equations</span> used include two second order flows, two fourth order flows and two sixth order flows. These nonlinear <span class="hlt">equations</span> are discretized based on discrete differential geometry operators. The proposed approach is simple, efficient and gives very desirable results, for a range of surface models, possibly having sharp creases and corners.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/AD1037543','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/AD1037543"><span>Stochastic Evolution <span class="hlt">Equations</span> Driven by Fractional Noises</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2016-11-28</p> <p>Stochastic Evolution <span class="hlt">Equations</span> Driven by Fractional Noises We have introduced a modification of the classical Euler numerical scheme for stochastic...of Papers published in peer-reviewed journals: Final Report: Stochastic Evolution <span class="hlt">Equations</span> Driven by Fractional Noises Report Title We have introduced...case the evolution form of the <span class="hlt">equation</span> will involve a Stratonovich integral (or path-wise Young integral). The product can also be interpreted as a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016CNSNS..36..378L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016CNSNS..36..378L"><span>Exact solutions of population balance <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lin, Fubiao; Flood, Adrian E.; Meleshko, Sergey V.</p> <p>2016-07-01</p> <p>Population balance <span class="hlt">equations</span> have been used to model a wide range of processes including polymerization, crystallization, cloud formation, and cell dynamics, but the lack of analytical solutions necessitates the use of numerical techniques. The one-dimensional homogeneous population balance <span class="hlt">equation</span> with time dependent but size independent growth rate and time dependent nucleation rate is investigated. The corresponding system of <span class="hlt">equations</span> is solved analytically in this paper.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017CNSNS..45..220Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017CNSNS..45..220Z"><span>Lie symmetry analysis of the Heisenberg <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, Zhonglong; Han, Bo</p> <p>2017-04-01</p> <p>The Lie symmetry analysis is performed on the Heisenberg <span class="hlt">equation</span> from the statistical physics. Its Lie point symmetries and optimal system of one-dimensional subalgebras are determined. The similarity reductions and invariant solutions are obtained. Using the multipliers, some conservation laws are obtained. We prove that this <span class="hlt">equation</span> is nonlinearly self-adjoint. The conservation laws associated with symmetries of this <span class="hlt">equation</span> are constructed by means of Ibragimov's method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11088406','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11088406"><span>Material <span class="hlt">equations</span> for electromagnetism with toroidal polarizations.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dubovik, V M; Martsenyuk, M A; Saha, B</p> <p>2000-06-01</p> <p>With regard to the toroid contributions, a modified system of <span class="hlt">equations</span> of electrodynamics moving continuous media has been obtained. Alternative formalisms to introduce the toroid moment contributions in the <span class="hlt">equations</span> of electromagnetism has been worked out. The two four-potential formalism has been developed. Lorentz transformation laws for the toroid polarizations has been given. Covariant form of <span class="hlt">equations</span> of electrodynamics of continuous media with toroid polarizations has been written.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19730012763&hterms=boltzmann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dboltzmann','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19730012763&hterms=boltzmann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dboltzmann"><span>Approximation method for the kinetic Boltzmann <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shakhov, Y. M.</p> <p>1972-01-01</p> <p>The further development of a method for approximating the Boltzmann <span class="hlt">equation</span> is considered and a case of pseudo-Maxwellian molecules is treated in detail. A method of approximating the collision frequency is discussed along with a method for approximating the moments of the Boltzmann collision integral. Since the return collisions integral and the collision frequency are expressed through the distribution function moments, use of the proposed methods make it possible to reduce the Boltzmann <span class="hlt">equation</span> to a series of approximating <span class="hlt">equations</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19890000628&hterms=packing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dpacking','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19890000628&hterms=packing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dpacking"><span>Partitioning And Packing <span class="hlt">Equations</span> For Parallel Processing</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Arpasi, Dale J.; Milner, Edward J.</p> <p>1989-01-01</p> <p>Algorithm developed to identify parallelism in set of coupled ordinary differential <span class="hlt">equations</span> that describe physical system and to divide set into parallel computational paths, along with parts of solution proceeds independently of others during at least part of time. Path-identifying algorithm creates number of paths consisting of <span class="hlt">equations</span> that must be computed serially and table that gives dependent and independent arguments and "can start," "can end," and "must end" times of each <span class="hlt">equation</span>. "Must end" time used subsequently by packing algorithm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19890000628&hterms=packing+algorithm&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dpacking%2Balgorithm','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19890000628&hterms=packing+algorithm&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dpacking%2Balgorithm"><span>Partitioning And Packing <span class="hlt">Equations</span> For Parallel Processing</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Arpasi, Dale J.; Milner, Edward J.</p> <p>1989-01-01</p> <p>Algorithm developed to identify parallelism in set of coupled ordinary differential <span class="hlt">equations</span> that describe physical system and to divide set into parallel computational paths, along with parts of solution proceeds independently of others during at least part of time. Path-identifying algorithm creates number of paths consisting of <span class="hlt">equations</span> that must be computed serially and table that gives dependent and independent arguments and "can start," "can end," and "must end" times of each <span class="hlt">equation</span>. "Must end" time used subsequently by packing algorithm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PhyA..387.6505T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PhyA..387.6505T"><span>Fokker Planck <span class="hlt">equation</span> with fractional coordinate derivatives</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tarasov, Vasily E.; Zaslavsky, George M.</p> <p>2008-11-01</p> <p>Using the generalized Kolmogorov-Feller <span class="hlt">equation</span> with long-range interaction, we obtain kinetic <span class="hlt">equations</span> with fractional derivatives with respect to coordinates. The method of successive approximations, with averaging with respect to a fast variable, is used. The main assumption is that the correlation function of probability densities of particles to make a step has a power-law dependence. As a result, we obtain a Fokker-Planck <span class="hlt">equation</span> with fractional coordinate derivative of order 1<α<2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1983PhRvB..27.4475K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1983PhRvB..27.4475K"><span>Renormalization group and linear integral <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Klein, W.</p> <p>1983-04-01</p> <p>We develop a position-space renormalization-group transformation which can be employed to study general linear integral <span class="hlt">equations</span>. In this Brief Report we employ our method to study one class of such <span class="hlt">equations</span> pertinent to the equilibrium properties of fluids. The results of applying our method are in excellent agreement with known numerical calculations where they can be compared. We also obtain information about the singular behavior of this type of <span class="hlt">equation</span> which could not be obtained numerically.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/783765','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/783765"><span>Some remarks on unilateral matrix <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cerchiai, Bianca L.; Zumino, Bruno</p> <p>2001-02-01</p> <p>We briefly review the results of our paper LBNL-46775: We study certain solutions of left-unilateral matrix <span class="hlt">equations</span>. These are algebraic <span class="hlt">equations</span> where the coefficients and the unknown are square matrices of the same order, or, more abstractly, elements of an associative, but possibly noncommutative algebra, and all coefficients are on the left. Recently such <span class="hlt">equations</span> have appeared in a discussion of generalized Born-Infeld theories. In particular, two <span class="hlt">equations</span>, their perturbative solutions and the relation between them are studied, applying a unified approach based on the generalized Bezout theorem for matrix polynomials.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017InJPh..91.1089L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017InJPh..91.1089L"><span>About vortex <span class="hlt">equations</span> of two dimensional flows</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, S.; Ryi, S.; Lim, H.</p> <p>2017-09-01</p> <p>A method to obtain a time-independent vortex solution of a nonlinear differential <span class="hlt">equation</span> describing two-dimensional flow is investigated. In the usual way, starting from the Navier-Stokes <span class="hlt">equation</span> the vortex <span class="hlt">equation</span> is derived by taking a curl operation. After rearranging the <span class="hlt">equation</span> of the vortex, we get a continuity <span class="hlt">equation</span> or a divergence-free <span class="hlt">equation</span>: partial _1V_1+partial _2V_2=0. Additional irrotationality of V_1 and V_2 leads us to the Cauchy-Riemann condition satisfied by a newly introduced stream function Ψ and velocity potential Φ. As a result, if we know V_1 and V_2 or a combination of two, the differential <span class="hlt">equation</span> is mapped to a lower-order partial differential <span class="hlt">equation</span>. This differential <span class="hlt">equation</span> is the one satisfied by the stream function ψ where the vorticity vector ω is given by -(partial _1^2+partial _2^2) ψ. A simple solution is discussed for the two different limits of viscosity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvD..91h5024H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvD..91h5024H"><span>Analytic solutions of the relativistic Boltzmann <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hatta, Yoshitaka; Martinez, Mauricio; Xiao, Bo-Wen</p> <p>2015-04-01</p> <p>We present new analytic solutions to the relativistic Boltzmann <span class="hlt">equation</span> within the relaxation time approximation. We first obtain spherically expanding solutions which are the kinetic counterparts of the exact solutions of the Israel-Stewart <span class="hlt">equation</span> in the literature. This allows us to compare the solutions of the kinetic and hydrodynamic <span class="hlt">equations</span> at an analytical level. We then derive a novel boost-invariant solution of the Boltzmann <span class="hlt">equation</span> which has an unconventional dependence on the proper time. The existence of such a solution is also suggested in second-order hydrodynamics and fluid-gravity correspondence.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/20776862','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/20776862"><span>Analytical solution of tt dilepton <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sonnenschein, Lars</p> <p>2006-03-01</p> <p>The top quark antiquark production system in the dilepton decay channel is described by a set of <span class="hlt">equations</span> which is nonlinear in the unknown neutrino momenta. Its most precise and least time consuming solution is of major importance for measurements of top quark properties like the top quark mass and tt spin correlations. The initial system of <span class="hlt">equations</span> can be transformed into two polynomial <span class="hlt">equations</span> with two unknowns by means of elementary algebraic operations. These two polynomials of multidegree two can be reduced to one univariate polynomial of degree four by means of resultants. The obtained quartic <span class="hlt">equation</span> is solved analytically.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/AD0649174','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/AD0649174"><span>ON A NONHOMOGENEOUS RANDOM DIFFUSION <span class="hlt">EQUATION</span>.</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p></p> <p>CORRELATION TECHNIQUES, FUNCTIONS(MATHEMATICS)), (*STOCHASTIC PROCESSES, <span class="hlt">EQUATIONS</span>), STATISTICAL FUNCTIONS, PROBABILITY, HILBERT SPACE, GREEN’S FUNCTION, SERIES(MATHEMATICS), ALLOYS, DIFFUSION , INTEGRALS</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/76406','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/76406"><span>Gibbs adsorption and the compressibility <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Aranovich, G.L.; Donohue, M.D.</p> <p>1995-08-08</p> <p>A new approach for deriving the <span class="hlt">equation</span> of state is developed. It is shown that the integral in the compressibility <span class="hlt">equation</span> is identical to the isotherm for Gibbs adsorption in radial coordinates. The Henry, Langmuir, and Frumkin adsorption isotherms are converted into <span class="hlt">equations</span> of state. It is shown that using Henry`s law gives an expression for the second virial coefficient that is identical to the result from statistical mechanics. Using the Langmuir isotherm leads to a new analytic expression for the hard-sphere <span class="hlt">equation</span> of state which can be explicit in either pressure or density. The Frumkin isotherm results in a new <span class="hlt">equation</span> of state for the square-well potential fluid. Conversely, new adsorption isotherms can be derived from <span class="hlt">equations</span> of state using the compressibility <span class="hlt">equation</span>. It is shown that the van der Waals <span class="hlt">equation</span> gives an adsorption isotherm <span class="hlt">equation</span> that describes both polymolecular adsorption and the unusual adsorption behavior observed for supercritical fluids. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19750033973&hterms=Nonlinear+partial+differential+equations&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DNonlinear%2Bpartial%2Bdifferential%2Bequations','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19750033973&hterms=Nonlinear+partial+differential+equations&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DNonlinear%2Bpartial%2Bdifferential%2Bequations"><span>Prolongation structures of nonlinear evolution <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wahlquist, H. D.; Estabrook, F. B.</p> <p>1975-01-01</p> <p>A technique is developed for systematically deriving a 'prolongation structure' - a set of interrelated potentials and pseudopotentials - for nonlinear partial differential <span class="hlt">equations</span> in two independent variables. When this is applied to the Korteweg-de Vries <span class="hlt">equation</span>, a new infinite set of conserved quantities is obtained. Known solution techniques are shown to result from the discovery of such a structure: related partial differential <span class="hlt">equations</span> for the potential functions, linear 'inverse scattering' <span class="hlt">equations</span> for auxiliary functions, Backlund transformations. Generalizations of these techniques will result from the use of irreducible matrix representations of the prolongation structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999NCimB.114.1239Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999NCimB.114.1239Z"><span>Scalar field in standard cosmology: time <span class="hlt">equation</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zecca, A.</p> <p>1999-11-01</p> <p>The separated time <span class="hlt">equation</span> relative to the generalized Klein-Gordon <span class="hlt">equation</span> in the Robertson-Walker space-time is integrated in the background of the standard cosmology. The solutions are given in terms of series that are obtained by the usual integration method of differential <span class="hlt">equations</span> with regular singularity. The normalization of the solutions implied by the requirement of second quantization of the scalar field is performed. The result exhausts the requirement of providing an explicit complete set of normal mode solutions of the scalar field <span class="hlt">equation</span> in standard cosmology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22617267','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22617267"><span>Optimal Control for Stochastic Delay Evolution <span class="hlt">Equations</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Meng, Qingxin; Shen, Yang</p> <p>2016-08-15</p> <p>In this paper, we investigate a class of infinite-dimensional optimal control problems, where the state <span class="hlt">equation</span> is given by a stochastic delay evolution <span class="hlt">equation</span> with random coefficients, and the corresponding adjoint <span class="hlt">equation</span> is given by an anticipated backward stochastic evolution <span class="hlt">equation</span>. We first prove the continuous dependence theorems for stochastic delay evolution <span class="hlt">equations</span> and anticipated backward stochastic evolution <span class="hlt">equations</span>, and show the existence and uniqueness of solutions to anticipated backward stochastic evolution <span class="hlt">equations</span>. Then we establish necessary and sufficient conditions for optimality of the control problem in the form of Pontryagin’s maximum principles. To illustrate the theoretical results, we apply stochastic maximum principles to study two examples, an infinite-dimensional linear-quadratic control problem with delay and an optimal control of a Dirichlet problem for a stochastic partial differential <span class="hlt">equation</span> with delay. Further applications of the two examples to a Cauchy problem for a controlled linear stochastic partial differential <span class="hlt">equation</span> and an optimal harvesting problem are also considered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JPhCS.788a2025K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JPhCS.788a2025K"><span>Spinor representation of Maxwell’s <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kulyabov, D. S.; Korolkova, A. V.; Sevastianov, L. A.</p> <p>2017-01-01</p> <p>Spinors are more special objects than tensor. Therefore possess more properties than the more generic objects such as tensors. Thus, the group of Lorentz two-spinors is the covering group of the Lorentz group. Since the Lorentz group is a symmetry group of Maxwell’s <span class="hlt">equations</span>, it is assumed to reasonable to use when writing the Maxwell <span class="hlt">equations</span> Lorentz two-spinors and not tensors. We describe in detail the representation of the Maxwell’s <span class="hlt">equations</span> in the form of Lorentz two-spinors. This representation of Maxwell’s <span class="hlt">equations</span> can be of considerable theoretical interest.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12513557','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12513557"><span>Fractional Schrödinger <span class="hlt">equation</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Laskin, Nick</p> <p>2002-11-01</p> <p>Some properties of the fractional Schrödinger <span class="hlt">equation</span> are studied. We prove the Hermiticity of the fractional Hamilton operator and establish the parity conservation law for fractional quantum mechanics. As physical applications of the fractional Schrödinger <span class="hlt">equation</span> we find the energy spectra of a hydrogenlike atom (fractional "Bohr atom") and of a fractional oscillator in the semiclassical approximation. An <span class="hlt">equation</span> for the fractional probability current density is developed and discussed. We also discuss the relationships between the fractional and standard Schrödinger <span class="hlt">equations</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017Nonli..30.3932B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017Nonli..30.3932B"><span>Symmetric solutions of evolutionary partial differential <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bruell, Gabriele; Ehrnström, Mats; Geyer, Anna; Pei, Long</p> <p>2017-10-01</p> <p>We show that for a large class of evolutionary nonlinear and nonlocal partial differential <span class="hlt">equations</span>, symmetry of solutions implies very restrictive properties of the solutions and symmetry axes. These restrictions are formulated in terms of three principles, based on the structure of the <span class="hlt">equations</span>. The first principle covers <span class="hlt">equations</span> that allow for steady solutions and shows that any spatially symmetric solution is in fact steady with a speed determined by the motion of the axis of symmetry at the initial time. The second principle includes <span class="hlt">equations</span> that admit breathers and steady waves, and therefore is less strong: it holds that the axes of symmetry are constant in time. The last principle is a mixed case, when the <span class="hlt">equation</span> contains terms of the kind from both earlier principles, and there may be different outcomes; for a class of such <span class="hlt">equations</span> one obtains that a spatially symmetric solution must be constant in both time and space. We list and give examples of more than 30 well-known <span class="hlt">equations</span> and systems in one and several dimensions satisfying these principles; corresponding results for weak formulations of these <span class="hlt">equations</span> may be attained using the same techniques. Our investigation is a generalisation of a local and one-dimensional version of the first principle from Ehrnström et al (2009 Int. Math. Res. Not. 2009 4578–96) to nonlocal <span class="hlt">equations</span>, systems and higher dimensions, as well as a study of the standing and mixed cases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EJPh...33..805P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EJPh...33..805P"><span>Simple derivation of the Lindblad <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pearle, Philip</p> <p>2012-07-01</p> <p>The Lindblad <span class="hlt">equation</span> is an evolution <span class="hlt">equation</span> for the density matrix in quantum theory. It is the general linear, Markovian, form which ensures that the density matrix is Hermitian, trace 1, positive and completely positive. Some elementary examples of the Lindblad <span class="hlt">equation</span> are given. The derivation of the Lindblad <span class="hlt">equation</span> presented here is ‘simple’ in that all it uses is the expression of a Hermitian matrix in terms of its orthonormal eigenvectors and real eigenvalues. Thus, it is appropriate for students who have learned the algebra of quantum theory. Where helpful, arguments are first given in a two-dimensional Hilbert space.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19800037736&hterms=golberg&qs=N%3D0%26Ntk%3DAuthor-Name%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dgolberg','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19800037736&hterms=golberg&qs=N%3D0%26Ntk%3DAuthor-Name%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dgolberg"><span>Integral <span class="hlt">equations</span> for flows in wind tunnels</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fromme, J. A.; Golberg, M. A.</p> <p>1979-01-01</p> <p>This paper surveys recent work on the use of integral <span class="hlt">equations</span> for the calculation of wind tunnel interference. Due to the large number of possible physical situations, the discussion is limited to two-dimensional subsonic and transonic flows. In the subsonic case, the governing boundary value problems are shown to reduce to a class of Cauchy singular <span class="hlt">equations</span> generalizing the classical airfoil <span class="hlt">equation</span>. The theory and numerical solution are developed in some detail. For transonic flows nonlinear singular <span class="hlt">equations</span> result, and a brief discussion of the work of Kraft and Kraft and Lo on their numerical solution is given. Some typical numerical results are presented and directions for future research are indicated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PhDT........19Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PhDT........19Y"><span>Growth estimates for Dyson-Schwinger <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yeats, Karen Amanda</p> <p></p> <p>Dyson-Schwinger <span class="hlt">equations</span> are integral <span class="hlt">equations</span> in quantum field theory that describe the Green functions of a theory and mirror the recursive decomposition of Feynman diagrams into subdiagrams. Taken as recursive <span class="hlt">equations</span>, the Dyson-Schwinger <span class="hlt">equations</span> describe perturbative quantum field theory. However, they also contain non-perturbative information. Using the Hopf algebra of Feynman graphs we will follow a sequence of reductions to convert the Dyson-Schwinger <span class="hlt">equations</span> to the following system of differential <span class="hlt">equations</span>, gr1x =Prx- sign srg r1x2 +j∈R sjg j1x x6xgr 1x where r∈R,R is the set of amplitudes of the theory which need renormalization, gr1 is the anomalous dimension associated to r, Pr( x) is a modified version of the function for the primitive skeletons contributing to r, and x is the coupling constant. Next, we approach the new system of differential <span class="hlt">equations</span> as a system of recursive <span class="hlt">equations</span> by expanding gr1x =Sn≥1gr1,nx n . We obtain the radius of convergence of Sgr1,nxn/n! in terms of that of SPrnx n/n! . In particular we show that a Lipatov bound for the growth of the primitives leads to a Lipatov bound for the whole theory. Finally, we make a few observations on the new system considered as differential <span class="hlt">equations</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AIPC.1570..343G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AIPC.1570..343G"><span>Far field expansion for Hartree type <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Georgiev, V.; Venkov, G.</p> <p>2013-12-01</p> <p>We consider the scalar field <span class="hlt">equation</span> -Δu(x)+(1/|x|*u2(x))u(x)-E2u(x)/|x|+u(x) = 0 where u = u(|x|) is a radial positive solution and * is the convolution operator in R3. This <span class="hlt">equation</span> can be rewritten as ordinary differential <span class="hlt">equation</span> -ru"(r)-2u'(r)+r ∫ r∞(1/s-1/r)u2(s)s2dsu(r)+ru(r) = 0 and this note is concerned with asymptotic behavior at infinity of solutions of this <span class="hlt">equation</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/783741','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/783741"><span>Some remarks on unilateral matrix <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cerchiai, Bianca L.; Zumino, Bruno</p> <p>2001-02-01</p> <p>We briefly review the results of our paper LBNL-46775: We study certain solutions of left-unilateral matrix <span class="hlt">equations</span>. These are algebraic <span class="hlt">equations</span> where the coefficients and the unknown are square matrices of the same order, or, more abstractly, elements of an associative, but possibly noncommutative algebra, and all coefficients are on the left. Recently such <span class="hlt">equations</span> have appeared in a discussion of generalized Born-Infeld theories. In particular, two <span class="hlt">equations</span>, their perturbative solutions and the relation between them are studied, applying a unified approach based on the generalized Bezout theorem for matrix polynomials.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22617365','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22617365"><span>On implicit abstract neutral nonlinear differential <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hernández, Eduardo; O’Regan, Donal</p> <p>2016-04-15</p> <p>In this paper we continue our developments in Hernández and O’Regan (J Funct Anal 261:3457–3481, 2011) on the existence of solutions for abstract neutral differential <span class="hlt">equations</span>. In particular we extend the results in Hernández and O’Regan (J Funct Anal 261:3457–3481, 2011) for the case of implicit nonlinear neutral <span class="hlt">equations</span> and we focus on applications to partial “nonlinear” neutral differential <span class="hlt">equations</span>. Some applications involving partial neutral differential <span class="hlt">equations</span> are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPhCS.681a2025S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPhCS.681a2025S"><span>Resonance regions of extended Mathieu <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Semyonov, V. P.; Timofeev, A. V.</p> <p>2016-02-01</p> <p>One of the mechanisms of energy transfer between degrees of freedom of dusty plasma system is based on parametric resonance. Initial stage of this process can de described by <span class="hlt">equation</span> similar to Mathieu <span class="hlt">equation</span>. Such <span class="hlt">equation</span> is studied by analytical and numerical approach. The numerical solution of the extended Mathieu <span class="hlt">equation</span> is obtained for a wide range of parameter values. Boundaries of resonance regions, growth rates of amplitudes and times of onset are obtained. The energy transfer between the degrees of freedom of dusty plasma system can occur over a wide range of frequencies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PhyA..471..212R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PhyA..471..212R"><span>Generalized Thomas-Fermi <span class="hlt">equations</span> as the Lampariello class of Emden-Fowler <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rosu, Haret C.; Mancas, Stefan C.</p> <p>2017-04-01</p> <p>A one-parameter family of Emden-Fowler <span class="hlt">equations</span> defined by Lampariello's parameter p which, upon using Thomas-Fermi boundary conditions, turns into a set of generalized Thomas-Fermi <span class="hlt">equations</span> comprising the standard Thomas-Fermi <span class="hlt">equation</span> for p = 1 is studied in this paper. The entire family is shown to be non integrable by reduction to the corresponding Abel <span class="hlt">equations</span> whose invariants do not satisfy a known integrability condition. We also discuss the equivalent dynamical system of <span class="hlt">equations</span> for the standard Thomas-Fermi <span class="hlt">equation</span> and perform its phase-plane analysis. The results of the latter analysis are similar for the whole class.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ZNatA..70..122K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ZNatA..70..122K"><span>Exact Travelling Wave Solutions of the Nonlinear Evolution <span class="hlt">Equations</span> by Auxiliary <span class="hlt">Equation</span> Method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kaplan, Melike; Akbulut, Arzu; Bekir, Ahmet</p> <p>2015-10-01</p> <p>The auxiliary <span class="hlt">equation</span> method presents wide applicability to handling nonlinear wave <span class="hlt">equations</span>. In this article, we establish new exact travelling wave solutions of the nonlinear Zoomeron <span class="hlt">equation</span>, coupled Higgs <span class="hlt">equation</span>, and equal width wave <span class="hlt">equation</span>. The travelling wave solutions are expressed by the hyperbolic functions, trigonometric functions, and rational functions. It is shown that the proposed method provides a powerful mathematical tool for solving nonlinear wave <span class="hlt">equations</span> in mathematical physics and engineering. Throughout the article, all calculations are made with the aid of the Maple packet program.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21251526','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21251526"><span>Cylindrical nonlinear Schroedinger <span class="hlt">equation</span> versus cylindrical Korteweg-de Vries <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fedele, Renato; De Nicola, Sergio; Grecu, Dan; Visinescu, Anca; Shukla, Padma K.</p> <p>2008-10-15</p> <p>A correspondence between the family of cylindrical nonlinear Schroedinger (cNLS) <span class="hlt">equations</span> and the one of cylindrical Korteweg-de Vries (cKdV) <span class="hlt">equations</span> is constructed. It associates non stationary solutions of the first family with the ones of the second family. This is done by using a correspondence, recently found, between the families of generalized NLS <span class="hlt">equation</span> and generalized KdV <span class="hlt">equation</span>, and their solutions in the form of travelling waves, respectively. In particular, non-stationary soliton-like solutions of the cNLS <span class="hlt">equation</span> can be associated with non-stationary soliton-like solutions of cKdV <span class="hlt">equation</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995AIPC..334..897P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995AIPC..334..897P"><span>Covariant <span class="hlt">equations</span> for the NN-πNN system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Phillips, D. R.; Afnan, I. R.</p> <p>1995-05-01</p> <p>We explain the deficiencies of the current NN-πNN <span class="hlt">equations</span>, sketch the derivation of a set of covariant NN-πNN <span class="hlt">equations</span> and describe the ways in which these <span class="hlt">equations</span> differ from previous sets of covariant <span class="hlt">equations</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFMNG31C1607C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFMNG31C1607C"><span>Constitutive <span class="hlt">Equation</span> for Anisotropic Rock</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cazacu, O.</p> <p>2006-12-01</p> <p>In many rocks, due to the existence of well-defined fabric elements such as bedding, layering, foliation or lamination planes, or due to the existence of linear structures, anisotropy can be important. The symmetries most frequently encountered are: transverse isotropy and orthotropy. By adopting both theoretical and experimental approaches, many authors have investigated the effect of the presence within the rock of pronounced anisotropic feature on the mechanical behavior in the elastic regime and on strength properties. Fewer attempts however have been made to capture the anisotropy of rocks in the plastic range. In this paper an elastic/viscoplastic non-associated constitutive <span class="hlt">equation</span> for an initially transversely isotropic material is presented. The model captures the observed dependency of the elastic moduli on the stress state. The limit of the elastic domain is given by an yield function whose expression is a priori unknown and is determined from data. The basic assumption adopted is that the type of anisotropy of the rock does not change during the deformation process. The anisotropy is thus described by a fourth order tensor invariant with respect to any transformation belonging to the symmetry group of the material. This tensor is assumed to be constant: it does not depend on time nor on deformation; A is involved in the expression of the flow rule, of the yield function, and of the failure criterion in the form of a transformed stress tensor. The components of the anisotropic tensor A are determined from the compressive strengths in conjunction with an anisotropic short- term failure The irreversibility is supposed to be due to transient creep, the irreversible stress work per unit volume being considered as hardening parameter. The adequacy of the model is demonstrated by applying it to a stratified sedimentary rock, Tournemire shale.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995JOSAA..12.1254T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995JOSAA..12.1254T"><span>Relation between the Rayleigh <span class="hlt">equation</span> in diffraction theory and the <span class="hlt">equation</span> based on Green's formula</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tatarskii, V. I.</p> <p>1995-06-01</p> <p>The steps necessary to produce the Rayleigh <span class="hlt">equation</span> that is based on the Rayleigh hypothesis from the <span class="hlt">equation</span> that is based on the Green's formula are shown. First a definition is given for the scattering amplitude that is true not only in the far zone of diffraction but also near the scattering surface. With this definition the Rayleigh <span class="hlt">equation</span> coincides with the rigorous <span class="hlt">equation</span> for the surface secondary sources that is based on Green's formula. The Rayleigh hypothesis is equivalent to substituting the far-zone expression of the scattering amplitude into this rigorous <span class="hlt">equation</span>. In this case it turns out to be the <span class="hlt">equation</span> not for the sources but directly for the scattering amplitude, which is the main advantage of this method. For comparing the Rayleigh <span class="hlt">equation</span> with the initial rigorous <span class="hlt">equation</span>, the Rayleigh <span class="hlt">equation</span> is represented in terms of secondary sources. The kernel of this <span class="hlt">equation</span> contains an integral that converges for positive and diverges for negative values of some parameter. It is shown that if we regularize this integral, defining it for the negative values of this parameter as an analytical continuation from the domain of positive values, this kernel becomes equal to the kernel of the initial rigorous <span class="hlt">equation</span>. It follows that the formal perturbation series for the scattering amplitude obtained from the Rayleigh <span class="hlt">equation</span> and from Green's <span class="hlt">equation</span> always coincide. This means that convergence of the perturbation series is a sufficient condition</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=omega&pg=2&id=EJ857937','ERIC'); return false;" href="http://eric.ed.gov/?q=omega&pg=2&id=EJ857937"><span>The Forced van der Pol <span class="hlt">Equation</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Fay, Temple H.</p> <p>2009-01-01</p> <p>We report on a study of the forced van der Pol <span class="hlt">equation</span> x + [epsilon](x[superscript 2] - 1)x + x = F cos[omega]t, by solving numerically the differential <span class="hlt">equation</span> for a variety of values of the parameters [epsilon], F and [omega]. In doing so, many striking and interesting trajectories can be discovered and phenomena such as frequency entrainment,…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19770021807&hterms=differential+ordinary+equation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Ddifferential%2Bordinary%2Bequation','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19770021807&hterms=differential+ordinary+equation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Ddifferential%2Bordinary%2Bequation"><span>MACSYMA's symbolic ordinary differential <span class="hlt">equation</span> solver</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Golden, J. P.</p> <p>1977-01-01</p> <p>The MACSYMA's symbolic ordinary differential <span class="hlt">equation</span> solver ODE2 is described. The code for this routine is delineated, which is of interest because it is written in top-level MACSYMA language, and may serve as a good example of programming in that language. Other symbolic ordinary differential <span class="hlt">equation</span> solvers are mentioned.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810031719&hterms=differential+ordinary+equation+nonlinear&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Ddifferential%2Bordinary%2Bequation%2Bnonlinear','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810031719&hterms=differential+ordinary+equation+nonlinear&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Ddifferential%2Bordinary%2Bequation%2Bnonlinear"><span>Singular perturbation <span class="hlt">equations</span> for flexible satellites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Huang, T. C.; Das, A.</p> <p>1980-01-01</p> <p>Force <span class="hlt">equations</span> of motion of the individual flexible elements of a satellite were obtained in a previous paper. Moment <span class="hlt">equations</span> of motion of the composite bodies of a flexible satellite are to be developed using two sets of <span class="hlt">equations</span> which form the basic system for any dynamic model of flexible satellites. This basic system consists of a set of N-coupled, nonlinear, ordinary, or partial differential <span class="hlt">equations</span>, for a flexible satellite with n generalized, structural position coordinates. For single composite body satellites, N is equal to (n + 3); for dual-spin systems, N is equal to (n + 9). These <span class="hlt">equations</span> involve time derivatives up to the second order. The study shows a method of avoiding this linearization by reducing the N <span class="hlt">equations</span> to 3 or 9 nonlinear, coupled, first order, ordinary, differential <span class="hlt">equations</span> involving only the angular velocities of the composite bodies. The solutions for these angular velocities lead to linear <span class="hlt">equations</span> in the n generalized structural position coordinates, which can be solved by known methods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=cameras+AND+work&pg=4&id=EJ831999','ERIC'); return false;" href="http://eric.ed.gov/?q=cameras+AND+work&pg=4&id=EJ831999"><span>Does the Wave <span class="hlt">Equation</span> Really Work?</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Armstead, Donald C.; Karls, Michael A.</p> <p>2006-01-01</p> <p>The wave <span class="hlt">equation</span> is a classic partial differential <span class="hlt">equation</span> that one encounters in an introductory course on boundary value problems or mathematical physics, which can be used to describe the vertical displacement of a vibrating string. Using a video camera and Wave-in-Motion software to record displacement data from a vibrating string or spring,…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=oxidation+AND+number&pg=2&id=EJ321581','ERIC'); return false;" href="http://eric.ed.gov/?q=oxidation+AND+number&pg=2&id=EJ321581"><span>How Should <span class="hlt">Equation</span> Balancing Be Taught?</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Porter, Spencer K.</p> <p>1985-01-01</p> <p>Matrix methods and oxidation-number methods are currently advocated and used for balancing <span class="hlt">equations</span>. This article shows how balancing <span class="hlt">equations</span> can be introduced by a third method which is related to a fundamental principle, is easy to learn, and is powerful in its application. (JN)</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18521608','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18521608"><span>Qualitative permanence of Lotka-Volterra <span class="hlt">equations</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hofbauer, Josef; Kon, Ryusuke; Saito, Yasuhisa</p> <p>2008-12-01</p> <p>In this paper, we consider permanence of Lotka-Volterra <span class="hlt">equations</span>. We investigate the sign structure of the interaction matrix that guarantees the permanence of a Lotka-Volterra <span class="hlt">equation</span> whenever it has a positive equilibrium point. An interaction matrix with this property is said to be qualitatively permanent. Our results provide both necessary and sufficient conditions for qualitative permanence.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22212870','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22212870"><span>Entropy viscosity method applied to Euler <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Delchini, M. O.; Ragusa, J. C.; Berry, R. A.</p> <p>2013-07-01</p> <p>The entropy viscosity method [4] has been successfully applied to hyperbolic systems of <span class="hlt">equations</span> such as Burgers <span class="hlt">equation</span> and Euler <span class="hlt">equations</span>. The method consists in adding dissipative terms to the governing <span class="hlt">equations</span>, where a viscosity coefficient modulates the amount of dissipation. The entropy viscosity method has been applied to the 1-D Euler <span class="hlt">equations</span> with variable area using a continuous finite element discretization in the MOOSE framework and our results show that it has the ability to efficiently smooth out oscillations and accurately resolve shocks. Two <span class="hlt">equations</span> of state are considered: Ideal Gas and Stiffened Gas <span class="hlt">Equations</span> Of State. Results are provided for a second-order time implicit schemes (BDF2). Some typical Riemann problems are run with the entropy viscosity method to demonstrate some of its features. Then, a 1-D convergent-divergent nozzle is considered with open boundary conditions. The correct steady-state is reached for the liquid and gas phases with a time implicit scheme. The entropy viscosity method correctly behaves in every problem run. For each test problem, results are shown for both <span class="hlt">equations</span> of state considered here. (authors)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19720048095&hterms=basic+algebra&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dbasic%2Balgebra','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19720048095&hterms=basic+algebra&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dbasic%2Balgebra"><span>Lie algebras and linear differential <span class="hlt">equations</span>.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brockett, R. W.; Rahimi, A.</p> <p>1972-01-01</p> <p>Certain symmetry properties possessed by the solutions of linear differential <span class="hlt">equations</span> are examined. For this purpose, some basic ideas from the theory of finite dimensional linear systems are used together with the work of Wei and Norman on the use of Lie algebraic methods in differential <span class="hlt">equation</span> theory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=consumer+AND+spending&pg=2&id=EJ231058','ERIC'); return false;" href="https://eric.ed.gov/?q=consumer+AND+spending&pg=2&id=EJ231058"><span>Recent Methodological Advances in Economic <span class="hlt">Equation</span> Systems.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Theil, Henri; Clements, Kenneth W.</p> <p>1980-01-01</p> <p>Examines economic <span class="hlt">equation</span> systems by describing the simultaneous <span class="hlt">equation</span> model, its application to the economy as a whole, and a systemwide approach to microeconomics. The systems approach focuses on particular segments of the economy such as consumer spending. (Author/KC)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6967629','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6967629"><span>Global existence proof for relativistic Boltzmann <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Dudynski, M. ); Ekiel-Jezewska, M.L. )</p> <p>1992-02-01</p> <p>The existence and causality of solutions to the relativistic Boltzmann <span class="hlt">equation</span> in L[sup 1] and in L[sub loc][sup 1] are proved. The solutions are shown to satisfy physically natural a priori bounds, time-independent in L[sup 1]. The results rely upon new techniques developed for the nonrelativistic Boltzmann <span class="hlt">equation</span> by DiPerna and Lions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=complex+AND+number&pg=2&id=EJ908773','ERIC'); return false;" href="http://eric.ed.gov/?q=complex+AND+number&pg=2&id=EJ908773"><span>Solving Cubic <span class="hlt">Equations</span> by Polynomial Decomposition</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Kulkarni, Raghavendra G.</p> <p>2011-01-01</p> <p>Several mathematicians struggled to solve cubic <span class="hlt">equations</span>, and in 1515 Scipione del Ferro reportedly solved the cubic while participating in a local mathematical contest, but did not bother to publish his method. Then it was Cardano (1539) who first published the solution to the general cubic <span class="hlt">equation</span> in his book "The Great Art, or, The Rules of…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19810018240','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19810018240"><span>Symbolic Solution of Linear Differential <span class="hlt">Equations</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Feinberg, R. B.; Grooms, R. G.</p> <p>1981-01-01</p> <p>An algorithm for solving linear constant-coefficient ordinary differential <span class="hlt">equations</span> is presented. The computational complexity of the algorithm is discussed and its implementation in the FORMAC system is described. A comparison is made between the algorithm and some classical algorithms for solving differential <span class="hlt">equations</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21501240','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21501240"><span>On solvable Dirac <span class="hlt">equation</span> with polynomial potentials</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Stachowiak, Tomasz</p> <p>2011-01-15</p> <p>One-dimensional Dirac <span class="hlt">equation</span> is analyzed with regard to the existence of exact (or closed-form) solutions for polynomial potentials. The notion of Liouvillian functions is used to define solvability, and it is shown that except for the linear potentials the <span class="hlt">equation</span> in question is not solvable.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998TMP...115..737P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998TMP...115..737P"><span>Diophantine <span class="hlt">equations</span> related to quasicrystals: A note</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pelantová, E.; Perelomov, A. M.</p> <p>1998-06-01</p> <p>We give the general solution of three Diophantine <span class="hlt">equations</span> in the ring of integer of the algebraic number field ${\\bf Q}[{\\sqr 5}]$. These <span class="hlt">equations</span> are related to the problem of determination of the minimum distance in quasicrystals with fivefold symmetry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.H23E1241T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.H23E1241T"><span>Approximate Solution to the Generalized Boussinesq <span class="hlt">Equation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Telyakovskiy, A. S.; Mortensen, J.</p> <p>2010-12-01</p> <p>The traditional Boussinesq <span class="hlt">equation</span> describes motion of water in groundwater flows. It models unconfined groundwater flow under the Dupuit assumption that the equipotential lines are vertical, making the flowlines horizontal. The Boussinesq <span class="hlt">equation</span> is a nonlinear diffusion <span class="hlt">equation</span> with diffusivity depending linearly on water head. Here we analyze a generalization of the Boussinesq <span class="hlt">equation</span>, when the diffusivity is a power law function of water head. For example polytropic gases moving through porous media obey this <span class="hlt">equation</span>. Solving this <span class="hlt">equation</span> usually requires numerical approximations, but for certain classes of initial and boundary conditions an approximate analytical solution can be constructed. This work focuses on the latter approach, using the scaling properties of the <span class="hlt">equation</span>. We consider one-dimensional semi-infinite initially empty aquifer with boundary conditions at the inlet in case of cylindrical symmetry. Such situation represents the case of an injection well. Solutions would propagate with the finite speed. We construct an approximate scaling function, and we compare the approximate solution with the direct numerical solutions obtained by using the scaling properties of the <span class="hlt">equations</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Nonlinear+AND+partial+AND+differential+AND+equations&id=EJ892212','ERIC'); return false;" href="http://eric.ed.gov/?q=Nonlinear+AND+partial+AND+differential+AND+equations&id=EJ892212"><span>Solving Differential <span class="hlt">Equations</span> Using Modified Picard Iteration</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Robin, W. A.</p> <p>2010-01-01</p> <p>Many classes of differential <span class="hlt">equations</span> are shown to be open to solution through a method involving a combination of a direct integration approach with suitably modified Picard iterative procedures. The classes of differential <span class="hlt">equations</span> considered include typical initial value, boundary value and eigenvalue problems arising in physics and…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150021165','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150021165"><span>Energy <span class="hlt">Equation</span> Approximation in Fluid Mechanics</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goldstein, Arthur W.</p> <p>1959-01-01</p> <p>There is some confusion in the literature of fluid mechanics in regard to the correct form of the energy <span class="hlt">equation</span> for the study of the flow of nearly incompressible fluids. Several forms of the energy <span class="hlt">equation</span> and their use are therefore discussed in this note.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA501428','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA501428"><span><span class="hlt">Equation</span> of State of Ballistic Gelatin</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2008-06-23</p> <p>We determined the <span class="hlt">equation</span> of state for ballistic gelatin using the Brillouin scattering spectroscopy with a diamond anvil cell by measuring the...0 to 100 deg C between ambient and 12 GPa. We analyzed the Brillouin data using a high temperature Vinet <span class="hlt">equation</span> of state and obtained the bulk</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA546054','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA546054"><span><span class="hlt">Equation</span> of State of Ballistic Gelatin (II)</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2011-01-03</p> <p>We determined the <span class="hlt">equation</span> of state of ballistic gelatin (20%) using Brillouin scattering spectroscopy with diamond anvil cells by measuring the...purposes, we also measured the pressure dependence of sound velocity of lamb tissues up to 10 GPa. We analyzed the Brillouin data using the Vinet <span class="hlt">equation</span> of state and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=Euler%2c+AND+Leonhard&id=EJ440172','ERIC'); return false;" href="https://eric.ed.gov/?q=Euler%2c+AND+Leonhard&id=EJ440172"><span>Euler's Amazing Way to Solve <span class="hlt">Equations</span>.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Flusser, Peter</p> <p>1992-01-01</p> <p>Presented is a series of examples that illustrate a method of solving <span class="hlt">equations</span> developed by Leonhard Euler based on an unsubstantiated assumption. The method integrates aspects of recursion relations and sequences of converging ratios and can be extended to polynomial <span class="hlt">equation</span> with infinite exponents. (MDH)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/765639','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/765639"><span>Operational <span class="hlt">equations</span> for data in common arrays</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Silver, G.L.</p> <p>2000-10-01</p> <p>A new method for interpolating experimental data by means of the shifting operator was introduced in 1985. This report illustrates new interpolating <span class="hlt">equations</span> for data in the five-point rectangle and diamond configurations, new measures of central tendency, and new <span class="hlt">equations</span> for data at the vertices of a cube.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=standard+AND+addition+AND+method&pg=2&id=EJ1037236','ERIC'); return false;" href="https://eric.ed.gov/?q=standard+AND+addition+AND+method&pg=2&id=EJ1037236"><span>Improving the Bandwidth Selection in Kernel <span class="hlt">Equating</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Andersson, Björn; von Davier, Alina A.</p> <p>2014-01-01</p> <p>We investigate the current bandwidth selection methods in kernel <span class="hlt">equating</span> and propose a method based on Silverman's rule of thumb for selecting the bandwidth parameters. In kernel <span class="hlt">equating</span>, the bandwidth parameters have previously been obtained by minimizing a penalty function. This minimization process has been criticized by practitioners…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JPCRD..43d3102S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JPCRD..43d3102S"><span>A Fundamental <span class="hlt">Equation</span> of State for Ethanol</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schroeder, J. A.; Penoncello, S. G.; Schroeder, J. S.</p> <p>2014-12-01</p> <p>The existing fundamental <span class="hlt">equation</span> for ethanol demonstrates undesirable behavior in several areas and especially in the critical region. In addition, new experimental data have become available in the open literature since the publication of the current correlation. The development of a new fundamental <span class="hlt">equation</span> for ethanol, in the form of Helmholtz energy as a function of temperature and density, is presented. New, nonlinear fitting techniques, along with the new experimental data, are shown to improve the behavior of the fundamental <span class="hlt">equation</span>. Ancillary <span class="hlt">equations</span> are developed, including <span class="hlt">equations</span> for vapor pressure, saturated liquid density, saturated vapor density, and ideal gas heat capacity. Both the fundamental and ancillary <span class="hlt">equations</span> are compared to experimental data. The fundamental <span class="hlt">equation</span> can compute densities to within ±0.2%, heat capacities to within ±1%-2%, and speed of sound to within ±1%. Values of the vapor pressure and saturated vapor densities are represented to within ±1% at temperatures of 300 K and above, while saturated liquid densities are represented to within ±0.3% at temperatures of 200 K and above. The uncertainty of all properties is higher in the critical region and near the triple point. The <span class="hlt">equation</span> is valid for pressures up to 280 MPa and temperatures from 160 to 650 K.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=euler&pg=7&id=EJ440172','ERIC'); return false;" href="http://eric.ed.gov/?q=euler&pg=7&id=EJ440172"><span>Euler's Amazing Way to Solve <span class="hlt">Equations</span>.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Flusser, Peter</p> <p>1992-01-01</p> <p>Presented is a series of examples that illustrate a method of solving <span class="hlt">equations</span> developed by Leonhard Euler based on an unsubstantiated assumption. The method integrates aspects of recursion relations and sequences of converging ratios and can be extended to polynomial <span class="hlt">equation</span> with infinite exponents. (MDH)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=theory+AND+graphs&pg=7&id=EJ684039','ERIC'); return false;" href="http://eric.ed.gov/?q=theory+AND+graphs&pg=7&id=EJ684039"><span>The Specific Analysis of Structural <span class="hlt">Equation</span> Models</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>McDonald, Roderick P.</p> <p>2004-01-01</p> <p>Conventional structural <span class="hlt">equation</span> modeling fits a covariance structure implied by the <span class="hlt">equations</span> of the model. This treatment of the model often gives misleading results because overall goodness of fit tests do not focus on the specific constraints implied by the model. An alternative treatment arising from Pearl's directed acyclic graph theory…</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=flexible+AND+hours+AND+own+AND+business&id=ED413447','ERIC'); return false;" href="http://eric.ed.gov/?q=flexible+AND+hours+AND+own+AND+business&id=ED413447"><span>The New Economic <span class="hlt">Equation</span>. Executive Summary.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Joshi, Pamela; Carre, Francoise; Place, Angela; Rayman, Paula</p> <p></p> <p>The New Economic <span class="hlt">Equation</span> Project opened in May 1995 with a 3-day working conference for 50 national leaders. The <span class="hlt">equation</span> was defined as follows: economic well-being = integration of work, family, and community. Conference participants identified key economic, work, and family concerns facing the United States today. Outreach activities in…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED462425.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED462425.pdf"><span>IRT <span class="hlt">Equating</span> of the MCAT. MCAT Monograph.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Hendrickson, Amy B.; Kolen, Michael J.</p> <p></p> <p>This study compared various <span class="hlt">equating</span> models and procedures for a sample of data from the Medical College Admission Test(MCAT), considering how item response theory (IRT) <span class="hlt">equating</span> results compare with classical equipercentile results and how the results based on use of various IRT models, observed score versus true score, direct versus linked…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19720048095&hterms=linear+algebra&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dlinear%2Balgebra','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19720048095&hterms=linear+algebra&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dlinear%2Balgebra"><span>Lie algebras and linear differential <span class="hlt">equations</span>.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brockett, R. W.; Rahimi, A.</p> <p>1972-01-01</p> <p>Certain symmetry properties possessed by the solutions of linear differential <span class="hlt">equations</span> are examined. For this purpose, some basic ideas from the theory of finite dimensional linear systems are used together with the work of Wei and Norman on the use of Lie algebraic methods in differential <span class="hlt">equation</span> theory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/11377','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/11377"><span>A Local Net Volume <span class="hlt">Equation</span> for Iowa</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Jerold T. Hahn</p> <p>1976-01-01</p> <p>As a part of the 1974 Forest Survey of Iowa, the Station''s Forst Resources Evaluatioin Research Staff developed a merchantable tree volume <span class="hlt">equation</span> and tables of coefficients for Iowa. They were developed for both board-foot (International ?-inch rule) and cubic foot volumes, for several species and species groups of growing-stock trees. The <span class="hlt">equation</span> and...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/10341','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/10341"><span>A net volume <span class="hlt">equation</span> for Indiana.</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>W. Brad Smith; Carol A. Weist</p> <p>1982-01-01</p> <p>Describes a Weibull-type volume <span class="hlt">equation</span> for Indiana developed as part of the ongoing Resource Evaluation research in the Central States. <span class="hlt">Equation</span> coefficients are presented by species groupings for both cubic foot and board foot volumes for three tree class categories.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950010045','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950010045"><span><span class="hlt">Equation</span> solvers for distributed-memory computers</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Storaasli, Olaf O.</p> <p>1994-01-01</p> <p>A large number of scientific and engineering problems require the rapid solution of large systems of simultaneous <span class="hlt">equations</span>. The performance of parallel computers in this area now dwarfs traditional vector computers by nearly an order of magnitude. This talk describes the major issues involved in parallel <span class="hlt">equation</span> solvers with particular emphasis on the Intel Paragon, IBM SP-1 and SP-2 processors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=differential&pg=4&id=EJ892212','ERIC'); return false;" href="https://eric.ed.gov/?q=differential&pg=4&id=EJ892212"><span>Solving Differential <span class="hlt">Equations</span> Using Modified Picard Iteration</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Robin, W. A.</p> <p>2010-01-01</p> <p>Many classes of differential <span class="hlt">equations</span> are shown to be open to solution through a method involving a combination of a direct integration approach with suitably modified Picard iterative procedures. The classes of differential <span class="hlt">equations</span> considered include typical initial value, boundary value and eigenvalue problems arising in physics and…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=kernel&id=EJ1037236','ERIC'); return false;" href="http://eric.ed.gov/?q=kernel&id=EJ1037236"><span>Improving the Bandwidth Selection in Kernel <span class="hlt">Equating</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Andersson, Björn; von Davier, Alina A.</p> <p>2014-01-01</p> <p>We investigate the current bandwidth selection methods in kernel <span class="hlt">equating</span> and propose a method based on Silverman's rule of thumb for selecting the bandwidth parameters. In kernel <span class="hlt">equating</span>, the bandwidth parameters have previously been obtained by minimizing a penalty function. This minimization process has been criticized by practitioners…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19860010881','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19860010881"><span>Breakdown of the conservative potential <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Salas, M. D.; Gumbert, C. R.</p> <p>1986-01-01</p> <p>The conservative full-potential <span class="hlt">equation</span> is used to study transonic flow over five airfoil sections. The results of the study indicate that once shock are present in the flow, the qualitative approximation is different from that observed with the Euler <span class="hlt">equations</span>. The difference in behavior of the potential eventually leads to multiple solutions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED336427.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED336427.pdf"><span>Congeneric Models and Levine's Linear <span class="hlt">Equating</span> Procedures.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Brennan, Robert L.</p> <p></p> <p>In 1955, R. Levine introduced two linear <span class="hlt">equating</span> procedures for the common-item non-equivalent populations design. His procedures make the same assumptions about true scores; they differ in terms of the nature of the <span class="hlt">equating</span> function used. In this paper, two parameterizations of a classical congeneric model are introduced to model the variables…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/33038','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/33038"><span>Modeling animal movements using stochastic differential <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Haiganoush K. Preisler; Alan A. Ager; Bruce K. Johnson; John G. Kie</p> <p>2004-01-01</p> <p>We describe the use of bivariate stochastic differential <span class="hlt">equations</span> (SDE) for modeling movements of 216 radiocollared female Rocky Mountain elk at the Starkey Experimental Forest and Range in northeastern Oregon. Spatially and temporally explicit vector fields were estimated using approximating difference <span class="hlt">equations</span> and nonparametric regression techniques. Estimated...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1304734','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1304734"><span>xRage <span class="hlt">Equation</span> of State</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Grove, John W.</p> <p>2016-08-16</p> <p>The xRage code supports a variety of hydrodynamic <span class="hlt">equation</span> of state (EOS) models. In practice these are generally accessed in the executing code via a pressure-temperature based table look up. This document will describe the various models supported by these codes and provide details on the algorithms used to evaluate the <span class="hlt">equation</span> of state.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/33580','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/33580"><span>Compatible taper <span class="hlt">equation</span> for loblolly pine</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>J. P. McClure; R. L. Czaplewski</p> <p>1986-01-01</p> <p>Cao's compatible, segmented polynomial taper <span class="hlt">equation</span> (Q. V. Cao, H. E. Burkhart, and T. A. Max. For. Sci. 26: 71-80. 1980) is fitted to a large loblolly pine data set from the southeastern United States. <span class="hlt">Equations</span> are presented that predict diameter at a given height, height to a given top diameter, and volume below a given position on the main stem. All...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009APS..SHK.W3002C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009APS..SHK.W3002C"><span>A Gallium Multiphase <span class="hlt">Equation</span> of State</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crockett, Scott; Greeff, Carl</p> <p>2009-06-01</p> <p>A new SESAME multiphase gallium <span class="hlt">equation</span> of state (EOS) has been developed. The <span class="hlt">equation</span> of state includes two of the solid phases (Ga I, Ga III) and a fluid phase. The EOS includes consistent latent heat between the phases. We compare the results to the liquid Hugoniot data. We will also explore refreezing via isentropic release and compression.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JCoAM.233.1596P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JCoAM.233.1596P"><span>Trotter products and reaction-diffusion <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Popescu, Emil</p> <p>2010-01-01</p> <p>In this paper, we study a class of generalized diffusion-reaction <span class="hlt">equations</span> of the form , where A is a pseudodifferential operator which generates a Feller semigroup. Using the Trotter product formula we give a corresponding discrete time integro-difference <span class="hlt">equation</span> for numerical solutions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EL....10528001D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EL....10528001D"><span>On the granular stress-geometry <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>DeGiuli, Eric; Schoof, Christian</p> <p>2014-01-01</p> <p>Using discrete calculus, we derive the missing stress-geometry <span class="hlt">equation</span> for rigid granular materials in two dimensions, in the mean-field approximation. We show that i) the <span class="hlt">equation</span> imposes that the voids cannot carry stress, ii) stress transmission is generically elliptic and has a quantitative relation to anisotropic elasticity, and iii) the packing fabric plays an essential role.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPhCS.766a2029E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPhCS.766a2029E"><span>A note on Berwald eikonal <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ekici, Cumali; Muradiye, Çimdiker</p> <p>2016-10-01</p> <p>In this study, firstly, we generalize Berwald map by introducing the concept of a Riemannian map. After that we find Berwald eikonal <span class="hlt">equation</span> through using the Berwald map. The eikonal <span class="hlt">equation</span> of geometrical optic that examining light reflects, refracts at smooth, plane interfaces is obtained for Berwald condition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=graph+AND+theory&pg=7&id=EJ684039','ERIC'); return false;" href="https://eric.ed.gov/?q=graph+AND+theory&pg=7&id=EJ684039"><span>The Specific Analysis of Structural <span class="hlt">Equation</span> Models</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>McDonald, Roderick P.</p> <p>2004-01-01</p> <p>Conventional structural <span class="hlt">equation</span> modeling fits a covariance structure implied by the <span class="hlt">equations</span> of the model. This treatment of the model often gives misleading results because overall goodness of fit tests do not focus on the specific constraints implied by the model. An alternative treatment arising from Pearl's directed acyclic graph theory…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED507814.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED507814.pdf"><span>Construction of Chained True Score Equipercentile <span class="hlt">Equatings</span> under the Kernel <span class="hlt">Equating</span> (KE) Framework and Their Relationship to Levine True Score <span class="hlt">Equating</span>. Research Report. ETS RR-09-24</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Chen, Haiwen; Holland, Paul</p> <p>2009-01-01</p> <p>In this paper, we develop a new chained equipercentile <span class="hlt">equating</span> procedure for the nonequivalent groups with anchor test (NEAT) design under the assumptions of the classical test theory model. This new <span class="hlt">equating</span> is named chained true score equipercentile <span class="hlt">equating</span>. We also apply the kernel <span class="hlt">equating</span> framework to this <span class="hlt">equating</span> design, resulting in a…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhLA..376.2588T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhLA..376.2588T"><span>A generalized fractional sub-<span class="hlt">equation</span> method for fractional differential <span class="hlt">equations</span> with variable coefficients</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tang, Bo; He, Yinnian; Wei, Leilei; Zhang, Xindong</p> <p>2012-08-01</p> <p>In this Letter, a generalized fractional sub-<span class="hlt">equation</span> method is proposed for solving fractional differential <span class="hlt">equations</span> with variable coefficients. Being concise and straightforward, this method is applied to the space-time fractional Gardner <span class="hlt">equation</span> with variable coefficients. As a result, many exact solutions are obtained including hyperbolic function solutions, trigonometric function solutions and rational solutions. It is shown that the considered method provides a very effective, convenient and powerful mathematical tool for solving many other fractional differential <span class="hlt">equations</span> in mathematical physics.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016IJMPB..3040018M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016IJMPB..3040018M"><span>Lump-type solutions to nonlinear differential <span class="hlt">equations</span> derived from generalized bilinear <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ma, Wen-Xiu; Zhou, Yuan; Dougherty, Rachael</p> <p>2016-08-01</p> <p>Lump-type solutions, rationally localized in many directions in the space, are analyzed for nonlinear differential <span class="hlt">equations</span> derived from generalized bilinear differential <span class="hlt">equations</span>. By symbolic computations with Maple, positive quadratic and quartic polynomial solutions to two classes of generalized bilinear differential <span class="hlt">equations</span> on f are computed, and thus, lump-type solutions are presented to the corresponding nonlinear differential <span class="hlt">equations</span> on u, generated from taking a transformation of dependent variables u = 2(ln f)x.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006JPhA...39.1151M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006JPhA...39.1151M"><span>Third-order integrable difference <span class="hlt">equations</span> generated by a pair of second-order <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Matsukidaira, Junta; Takahashi, Daisuke</p> <p>2006-02-01</p> <p>We show that the third-order difference <span class="hlt">equations</span> proposed by Hirota, Kimura and Yahagi are generated by a pair of second-order difference <span class="hlt">equations</span>. In some cases, the pair of the second-order <span class="hlt">equations</span> are equivalent to the Quispel-Robert-Thomson (QRT) system, but in the other cases, they are irrelevant to the QRT system. We also discuss an ultradiscretization of the <span class="hlt">equations</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AIPC.1863I0005Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AIPC.1863I0005Y"><span>Discrete fractional solutions of the radial <span class="hlt">equation</span> of the fractional Schrödinger <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yilmazer, Resat; Ozturk, Okkes</p> <p>2017-07-01</p> <p>One of the most popular research interests of science and engineering is the fractional calculus theory in recent times. Discrete fractional calculus (DFC) has also an important position in the fractional calculus. The nabla operator in DFC is practical for the singular differential <span class="hlt">equations</span>. In this study, we investigated the radial <span class="hlt">equation</span> of the fractional Schrödinger <span class="hlt">equation</span>. The particular solutions of this <span class="hlt">equation</span> was obtained as discrete fractional forms via ∇-discrete fractional operator out of known methods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19740041251&hterms=burger&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dburger','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19740041251&hterms=burger&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dburger"><span>Partial implicitization. [numerical stability of Burger <span class="hlt">equation</span> model for Navier-Stokes <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Graves, R. A., Jr.</p> <p>1973-01-01</p> <p>The steady-state solution to the full Navier-Stokes <span class="hlt">equations</span> for complicated flows is generally difficult to obtain. The Burgers (1948) <span class="hlt">equation</span> is used as a model of the Navier-Stokes <span class="hlt">equations</span>. The steady-state solution is obtained by a one-step explicit technique resulting from a partial implicitization of the difference <span class="hlt">equation</span>. Stability analysis shows that the technique is unconditionally stable, and numerical tests show the technique to be accurate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JMP....55h3301A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JMP....55h3301A"><span>Classical non-Markovian Boltzmann <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Alexanian, Moorad</p> <p>2014-08-01</p> <p>The modeling of particle transport involves anomalous diffusion, ⟨x2(t) ⟩ ∝ tα with α ≠ 1, with subdiffusive transport corresponding to 0 < α < 1 and superdiffusive transport to α > 1. These anomalies give rise to fractional advection-dispersion <span class="hlt">equations</span> with memory in space and time. The usual Boltzmann <span class="hlt">equation</span>, with only isolated binary collisions, is Markovian and, in particular, the contributions of the three-particle distribution function are neglected. We show that the inclusion of higher-order distribution functions give rise to an exact, non-Markovian Boltzmann <span class="hlt">equation</span> with resulting transport <span class="hlt">equations</span> for mass, momentum, and kinetic energy with memory in both time and space. The two- and the three-particle distribution functions are considered under the assumption that the two- and the three-particle correlation functions are translationally invariant that allows us to obtain advection-dispersion <span class="hlt">equations</span> for modeling transport in terms of spatial and temporal fractional derivatives.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19740030149&hterms=differential+ordinary+equation+nonlinear&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Ddifferential%2Bordinary%2Bequation%2Bnonlinear','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19740030149&hterms=differential+ordinary+equation+nonlinear&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Ddifferential%2Bordinary%2Bequation%2Bnonlinear"><span>Singular perturbation <span class="hlt">equations</span> for flexible satellites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Huang, T. C.; Das, A.</p> <p>1973-01-01</p> <p>The dynamic model of a flexible satellite with n generalized structural position coordinates requires the solution of a set of N coupled nonlinear ordinary or partial differential <span class="hlt">equations</span>. For single composite body satellites, N is equal to (n + 3). For dual-spin systems, N is equal to (n + 9). These <span class="hlt">equations</span> usually involve time derivatives up to the second order. For large values of n, linearization of the system has so far been the only practicable way of solution. The present study shows a method of avoiding this linearization by reducing the N <span class="hlt">equations</span> to three or nine nonlinear, coupled, first-order ordinary differential <span class="hlt">equations</span> involving only the angular velocities of the composite bodies. The solutions for these angular velocities lead to linear <span class="hlt">equations</span> in the n generalized structural position coordinates, which can then be solved by known methods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21409048','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21409048"><span><span class="hlt">Equation</span> of state of tracker fields</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chiba, Takeshi</p> <p>2010-01-15</p> <p>We derive the <span class="hlt">equation</span> of state of tracker fields, which are typical examples of freezing quintessence (quintessence with the <span class="hlt">equation</span> of state approaching toward -1), taking into account of the late-time departure from the tracker solution due to the nonzero density parameter of dark energy {Omega}{sub {phi}.} We calculate the <span class="hlt">equation</span> of state as a function of {Omega}{sub {phi}}for constant {Gamma}=VV{sup ''}/(V{sup '}){sup 2} (during matter era) models. The derived <span class="hlt">equation</span> of state contains a single parameter, w{sub (0)}, which parametrizes the <span class="hlt">equation</span> of state during the matter-dominated epoch. We derive observational constraints on w{sub (0)} and find that observational data are consistent with the cosmological constant: -1.11<w{sub (0)}<-0.96(1{sigma}).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19900001078','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19900001078"><span>Turbulence kinetic energy <span class="hlt">equation</span> for dilute suspensions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Abou-Arab, T. W.; Roco, M. C.</p> <p>1989-01-01</p> <p>A multiphase turbulence closure model is presented which employs one transport <span class="hlt">equation</span>, namely the turbulence kinetic energy <span class="hlt">equation</span>. The proposed form of this <span class="hlt">equation</span> is different from the earlier formulations in some aspects. The power spectrum of the carrier fluid is divided into two regions, which interact in different ways and at different rates with the suspended particles as a function of the particle-eddy size ratio and density ratio. The length scale is described algebraically. A mass/time averaging procedure for the momentum and kinetic energy <span class="hlt">equations</span> is adopted. The resulting turbulence correlations are modeled under less retrictive assumptions comparative to previous work. The closures for the momentum and kinetic energy <span class="hlt">equations</span> are given. Comparisons of the predictions with experimental results on liquid-solid jet and gas-solid pipe flow show satisfactory agreement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22306199','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22306199"><span>Classical non-Markovian Boltzmann <span class="hlt">equation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Alexanian, Moorad</p> <p>2014-08-01</p> <p>The modeling of particle transport involves anomalous diffusion, (x²(t) ) ∝ t{sup α} with α ≠ 1, with subdiffusive transport corresponding to 0 < α < 1 and superdiffusive transport to α > 1. These anomalies give rise to fractional advection-dispersion <span class="hlt">equations</span> with memory in space and time. The usual Boltzmann <span class="hlt">equation</span>, with only isolated binary collisions, is Markovian and, in particular, the contributions of the three-particle distribution function are neglected. We show that the inclusion of higher-order distribution functions give rise to an exact, non-Markovian Boltzmann <span class="hlt">equation</span> with resulting transport <span class="hlt">equations</span> for mass, momentum, and kinetic energy with memory in both time and space. The two- and the three-particle distribution functions are considered under the assumption that the two- and the three-particle correlation functions are translationally invariant that allows us to obtain advection-dispersion <span class="hlt">equations</span> for modeling transport in terms of spatial and temporal fractional derivatives.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012TRACE...5..371Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012TRACE...5..371Y"><span><span class="hlt">Equation</span> of State for Monochloropentafluoroethane (R115)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yin, Jian-Min; Yada, N.; Watanabe, K.</p> <p></p> <p>Based on the available experimental PVT measurements reported in the literature, a modified BWR <span class="hlt">equation</span> of state for refrigerant R115 (C2CIF5) is proposed. The characteristics of derived thermodynamic properties such as the isochoric specific heat capacity, the isobaric specific heat capacity and the speed of sound have been critically examined in developing the present <span class="hlt">equation</span>. The auxiliary saturated liquid density <span class="hlt">equation</span>, which has been used to calculate the saturated thermodynamic properties over a wide range of temperatures, is also developed. The developed <span class="hlt">equation</span> is effective for a range of temperatures from 220K to 450K and of pressures up to 10 MPa which corresponds to the density range up to 1,244 kg/m3. Comparisons with the available <span class="hlt">equations</span> of state are also discussed here.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19517504','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19517504"><span>Theory of electrophoresis: fate of one <span class="hlt">equation</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gas, Bohuslav</p> <p>2009-06-01</p> <p>Electrophoresis utilizes a difference in movement of charged species in a separation channel or space for their spatial separation. A basic partial differential <span class="hlt">equation</span> that results from the balance laws of continuous processes in separation sciences is the nonlinear conservation law or the continuity <span class="hlt">equation</span>. Attempts at its analytical solution in electrophoresis go back to Kohlrausch's days. The present paper (i) reviews derivation of conservation functions from the conservation law as appeared chronologically, (ii) deals with theory of moving boundary <span class="hlt">equations</span> and, mainly, (iii) presents the linear theory of eigenmobilities. It shows that a basic solution of the linearized continuity <span class="hlt">equations</span> is a set of traveling waves. In particular cases the continuity <span class="hlt">equation</span> can have a resonance solution that leads in practice to schizophrenic dispersion of peaks or a chaotic solution, which causes oscillation of electrolyte solutions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=426982','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=426982"><span>On Coupled Rate <span class="hlt">Equations</span> with Quadratic Nonlinearities</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Montroll, Elliott W.</p> <p>1972-01-01</p> <p>Rate <span class="hlt">equations</span> with quadratic nonlinearities appear in many fields, such as chemical kinetics, population dynamics, transport theory, hydrodynamics, etc. Such <span class="hlt">equations</span>, which may arise from basic principles or which may be phenomenological, are generally solved by linearization and application of perturbation theory. Here, a somewhat different strategy is emphasized. Alternative nonlinear models that can be solved exactly and whose solutions have the qualitative character expected from the original <span class="hlt">equations</span> are first searched for. Then, the original <span class="hlt">equations</span> are treated as perturbations of those of the solvable model. Hence, the function of the perturbation theory is to improve numerical accuracy of solutions, rather than to furnish the basic qualitative behavior of the solutions of the <span class="hlt">equations</span>. PMID:16592013</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21861561','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21861561"><span>Ordinary differential <span class="hlt">equation</span> for local accumulation time.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Berezhkovskii, Alexander M</p> <p>2011-08-21</p> <p>Cell differentiation in a developing tissue is controlled by the concentration fields of signaling molecules called morphogens. Formation of these concentration fields can be described by the reaction-diffusion mechanism in which locally produced molecules diffuse through the patterned tissue and are degraded. The formation kinetics at a given point of the patterned tissue can be characterized by the local accumulation time, defined in terms of the local relaxation function. Here, we show that this time satisfies an ordinary differential <span class="hlt">equation</span>. Using this <span class="hlt">equation</span> one can straightforwardly determine the local accumulation time, i.e., without preliminary calculation of the relaxation function by solving the partial differential <span class="hlt">equation</span>, as was done in previous studies. We derive this ordinary differential <span class="hlt">equation</span> together with the accompanying boundary conditions and demonstrate that the earlier obtained results for the local accumulation time can be recovered by solving this <span class="hlt">equation</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26026319','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26026319"><span>Riemann <span class="hlt">equation</span> for prime number diffusion.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, Wen; Liang, Yingjie</p> <p>2015-05-01</p> <p>This study makes the first attempt to propose the Riemann diffusion <span class="hlt">equation</span> to describe in a manner of partial differential <span class="hlt">equation</span> and interpret in physics of diffusion the classical Riemann method for prime number distribution. The analytical solution of this <span class="hlt">equation</span> is the well-known Riemann representation. The diffusion coefficient is dependent on natural number, a kind of position-dependent diffusivity diffusion. We find that the diffusion coefficient of the Riemann diffusion <span class="hlt">equation</span> is nearly a straight line having a slope 0.99734 in the double-logarithmic axis. Consequently, an approximate solution of the Riemann diffusion <span class="hlt">equation</span> is obtained, which agrees well with the Riemann representation in predicting the prime number distribution. Moreover, we interpret the scale-free property of prime number distribution via a power law function with 1.0169 the scale-free exponent in respect to logarithmic transform of the natural number, and then the fractal characteristic of prime number distribution is disclosed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1984PhRvB..30.1387K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1984PhRvB..30.1387K"><span>Linear integral <span class="hlt">equations</span> and renormalization group</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Klein, W.; Haymet, A. D. J.</p> <p>1984-08-01</p> <p>A formulation of the position-space renormalization-group (RG) technique is used to analyze the singular behavior of solutions to a number of integral <span class="hlt">equations</span> used in the theory of the liquid state. In particular, we examine the truncated Kirkwood-Salsburg <span class="hlt">equation</span>, the Ornstein-Zernike <span class="hlt">equation</span>, and a simple nonlinear <span class="hlt">equation</span> used in the mean-field theory of liquids. We discuss the differences in applying the position-space RG to lattice systems and to fluids, and the need for an explicit free-energy rescaling assumption in our formulation of the RG for integral <span class="hlt">equations</span>. Our analysis provides one natural way to define a "fractal" dimension at a phase transition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750015139','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750015139"><span>Almost periodic solutions to difference <span class="hlt">equations</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bayliss, A.</p> <p>1975-01-01</p> <p>The theory of Massera and Schaeffer relating the existence of unique almost periodic solutions of an inhomogeneous linear <span class="hlt">equation</span> to an exponential dichotomy for the homogeneous <span class="hlt">equation</span> was completely extended to discretizations by a strongly stable difference scheme. In addition it is shown that the almost periodic sequence solution will converge to the differential <span class="hlt">equation</span> solution. The preceding theory was applied to a class of exponentially stable partial differential <span class="hlt">equations</span> to which one can apply the Hille-Yoshida theorem. It is possible to prove the existence of unique almost periodic solutions of the inhomogeneous <span class="hlt">equation</span> (which can be approximated by almost periodic sequences) which are the solutions to appropriate discretizations. Two methods of discretizations are discussed: the strongly stable scheme and the Lax-Wendroff scheme.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=transformation+AND+methods&pg=5&id=EJ1027914','ERIC'); return false;" href="http://eric.ed.gov/?q=transformation+AND+methods&pg=5&id=EJ1027914"><span>Statistical Models and Inference for the True <span class="hlt">Equating</span> Transformation in the Context of Local <span class="hlt">Equating</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>González, B. Jorge; von Davier, Matthias</p> <p>2013-01-01</p> <p>Based on Lord's criterion of equity of <span class="hlt">equating</span>, van der Linden (this issue) revisits the so-called local <span class="hlt">equating</span> method and offers alternative as well as new thoughts on several topics including the types of transformations, symmetry, reliability, and population invariance appropriate for <span class="hlt">equating</span>. A remarkable aspect is to define equating…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=terms+AND+examination&pg=2&id=EJ1130875','ERIC'); return false;" href="https://eric.ed.gov/?q=terms+AND+examination&pg=2&id=EJ1130875"><span>A Comparative Analysis of Pre-<span class="hlt">Equating</span> and Post-<span class="hlt">Equating</span> in a Large-Scale Assessment, High Stakes Examination</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Ojerinde, Dibu; Popoola, Omokunmi; Onyeneho, Patrick; Egberongbe, Aminat</p> <p>2016-01-01</p> <p>Statistical procedure used in adjusting test score difficulties on test forms is known as "<span class="hlt">equating</span>". <span class="hlt">Equating</span> makes it possible for various test forms to be used interchangeably. In terms of where the <span class="hlt">equating</span> method fits in the assessment cycle, there are pre-<span class="hlt">equating</span> and post-<span class="hlt">equating</span> methods. The major benefits of pre-<span class="hlt">equating</span>, when…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhDT........11V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhDT........11V"><span>Solution Methods for Certain Evolution <span class="hlt">Equations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vega-Guzman, Jose Manuel</p> <p></p> <p>Solution methods for certain linear and nonlinear evolution <span class="hlt">equations</span> are presented in this dissertation. Emphasis is placed mainly on the analytical treatment of nonautonomous differential <span class="hlt">equations</span>, which are challenging to solve despite the existent numerical and symbolic computational software programs available. Ideas from the transformation theory are adopted allowing one to solve the problems under consideration from a non-traditional perspective. First, the Cauchy initial value problem is considered for a class of nonautonomous and inhomogeneous linear diffusion-type <span class="hlt">equation</span> on the entire real line. Explicit transformations are used to reduce the <span class="hlt">equations</span> under study to their corresponding standard forms emphasizing on natural relations with certain Riccati(and/or Ermakov)-type systems. These relations give solvability results for the Cauchy problem of the parabolic <span class="hlt">equation</span> considered. The superposition principle allows to solve formally this problem from an unconventional point of view. An eigenfunction expansion approach is also considered for this general evolution <span class="hlt">equation</span>. Examples considered to corroborate the efficacy of the proposed solution methods include the Fokker-Planck <span class="hlt">equation</span>, the Black-Scholes model and the one-factor Gaussian Hull-White model. The results obtained in the first part are used to solve the Cauchy initial value problem for certain inhomogeneous Burgers-type <span class="hlt">equation</span>. The connection between linear (the Diffusion-type) and nonlinear (Burgers-type) parabolic <span class="hlt">equations</span> is stress in order to establish a strong commutative relation. Traveling wave solutions of a nonautonomous Burgers <span class="hlt">equation</span> are also investigated. Finally, it is constructed explicitly the minimum-uncertainty squeezed states for quantum harmonic oscillators. They are derived by the action of corresponding maximal kinematical invariance group on the standard ground state solution. It is shown that the product of the variances attains the required minimum value</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3633383','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3633383"><span><span class="hlt">Inadequacy</span> the Health System in Serbia and Corrupt Institutions</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Dickov, Veselin</p> <p>2012-01-01</p> <p>Rapid changes in the health system require a new trained professionals who fully understand the processes of health and organizational problems and have the knowledge and skills that enable them to manage health care services. Health services to their largely rests on a system of solidarity and “socialism”, and only partly on market principle, and more than in other sectors of the economy requires individuals who are able to bridge that gap. Realize savings in the system that one side is not profitable, on the other hand is able to swallow a huge media arts is that simply needs to learn–just relying on common sense and intuition that no longer helps. The increase in costs. Advances in medicine and technology, and discovery of new drugs, namely, the almost daily increase the costs of diagnosis and treatment. Advances in medicine prolongs life expectancy by increasing the number of patients, especially those with chronic diseases, the biggest consumer of drugs and frequent guests hospital. PMID:23678330</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <center> <div class="footer-extlink text-muted"><small>Some links on this page may take you to non-federal websites. Their policies may differ from this site.</small> </div> </center> <div id="footer-wrapper"> <div class="footer-content"> <div id="footerOSTI" class=""> <div class="row"> <div class="col-md-4 text-center col-md-push-4 footer-content-center"><small><a href="http://www.science.gov/disclaimer.html">Privacy and Security</a></small> <div class="visible-sm visible-xs push_footer"></div> </div> <div class="col-md-4 text-center col-md-pull-4 footer-content-left"> <img src="https://www.osti.gov/images/DOE_SC31.png" alt="U.S. Department of Energy" usemap="#doe" height="31" width="177"><map style="display:none;" name="doe" id="doe"><area shape="rect" coords="1,3,107,30" href="http://www.energy.gov" alt="U.S. Deparment of Energy"><area shape="rect" coords="114,3,165,30" href="http://www.science.energy.gov" alt="Office of Science"></map> <a ref="http://www.osti.gov" style="margin-left: 15px;"><img src="https://www.osti.gov/images/footerimages/ostigov53.png" alt="Office of Scientific and Technical Information" height="31" width="53"></a> <div class="visible-sm visible-xs push_footer"></div> </div> <div class="col-md-4 text-center footer-content-right"> <a href="http://www.science.gov"><img src="https://www.osti.gov/images/footerimages/scigov77.png" alt="science.gov" height="31" width="98"></a> <a href="http://worldwidescience.org"><img src="https://www.osti.gov/images/footerimages/wws82.png" alt="WorldWideScience.org" height="31" width="90"></a> </div> </div> </div> </div> </div> <p><br></p> </div><!-- container --> <script type="text/javascript"><!-- // var lastDiv = ""; function showDiv(divName) { // hide last div if (lastDiv) { document.getElementById(lastDiv).className = "hiddenDiv"; } //if value of the box is not nothing and an object with that name exists, then change the class if (divName && document.getElementById(divName)) { document.getElementById(divName).className = "visibleDiv"; lastDiv = divName; } } //--> </script> <script> /** * Function that tracks a click on an outbound link in Google Analytics. * This function takes a valid URL string as an argument, and uses that URL string * as the event label. */ var trackOutboundLink = function(url,collectionCode) { try { h = window.open(url); setTimeout(function() { ga('send', 'event', 'topic-page-click-through', collectionCode, url); }, 1000); } catch(err){} }; </script> <!-- Google Analytics --> <script> (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){ (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o), m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m) })(window,document,'script','//www.google-analytics.com/analytics.js','ga'); ga('create', 'UA-1122789-34', 'auto'); ga('send', 'pageview'); </script> <!-- End Google Analytics --> <script> showDiv('page_1') </script> </body> </html>