Simple analytic approximations for the Blasius problem
NASA Astrophysics Data System (ADS)
Iacono, R.; Boyd, John P.
2015-08-01
The classical boundary layer problem formulated by Heinrich Blasius more than a century ago is revisited, with the purpose of deriving simple and accurate analytical approximations to its solution. This is achieved through the combined use of a generalized Padé approach and of an integral iteration scheme devised by Hermann Weyl. The iteration scheme is also used to derive very accurate bounds for the value of the second derivative of the Blasius function at the origin, which plays a crucial role in this problem.
Analytical and sensory quality characteristics of twelve blueberry cultivars
Technology Transfer Automated Retrieval System (TEKTRAN)
The analytical and sensory quality characteristics of twelve blueberry cultivars were evaluated to determine what fruit quality characteristics consumers consider important and to evaluate if sensory quality characteristics were correlated to any analytical quality characteristics. Cultivars evaluat...
Analytical solutions to matrix diffusion problems
Kekäläinen, Pekka
2014-10-06
We report an analytical method to solve in a few cases of practical interest the equations which have traditionally been proposed for the matrix diffusion problem. In matrix diffusion, elements dissolved in ground water can penetrate the porous rock surronuding the advective flow paths. In the context of radioactive waste repositories this phenomenon provides a mechanism by which the area of rock surface in contact with advecting elements is greatly enhanced, and can thus be an important delay mechanism. The cases solved are relevant for laboratory as well for in situ experiments. Solutions are given as integral representations well suited for easy numerical solution.
Analytic prediction of airplane equilibrium spin characteristics
NASA Technical Reports Server (NTRS)
Adams, W. M., Jr.
1972-01-01
The nonlinear equations of motion are solved algebraically for conditions for which an airplane is in an equilibrium spin. Constrained minimization techniques are employed in obtaining the solution. Linear characteristics of the airplane about the equilibrium points are also presented and their significance in identifying the stability characteristics of the equilibrium points is discussed. Computer time requirements are small making the method appear potentially applicable in airplane design. Results are obtained for several configurations and are compared with other analytic-numerical methods employed in spin prediction. Correlation with experimental results is discussed for one configuration for which a rather extensive data base was available. A need is indicated for higher Reynolds number data taken under conditions which more accurately simulate a spin.
Assessing Cognitive Learning of Analytical Problem Solving
NASA Astrophysics Data System (ADS)
Billionniere, Elodie V.
Introductory programming courses, also known as CS1, have a specific set of expected outcomes related to the learning of the most basic and essential computational concepts in computer science (CS). However, two of the most often heard complaints in such courses are that (1) they are divorced from the reality of application and (2) they make the learning of the basic concepts tedious. The concepts introduced in CS1 courses are highly abstract and not easily comprehensible. In general, the difficulty is intrinsic to the field of computing, often described as "too mathematical or too abstract." This dissertation presents a small-scale mixed method study conducted during the fall 2009 semester of CS1 courses at Arizona State University. This study explored and assessed students' comprehension of three core computational concepts---abstraction, arrays of objects, and inheritance---in both algorithm design and problem solving. Through this investigation students' profiles were categorized based on their scores and based on their mistakes categorized into instances of five computational thinking concepts: abstraction, algorithm, scalability, linguistics, and reasoning. It was shown that even though the notion of computational thinking is not explicit in the curriculum, participants possessed and/or developed this skill through the learning and application of the CS1 core concepts. Furthermore, problem-solving experiences had a direct impact on participants' knowledge skills, explanation skills, and confidence. Implications for teaching CS1 and for future research are also considered.
Small divisor problem for an analytic q-difference equation
NASA Astrophysics Data System (ADS)
Xu, Bing; Zhang, Weinian
2008-06-01
Similar to the problem of linearization, the "small divisor problem" also arises in the discussion of invertible analytic solutions of a class of q-difference equations. In this paper we give the existence of such solutions under the Brjuno condition and prove that the equation may not have a nontrivial analytic solution when the Brjuno condition is violated. These results are applied to discussing a nonlinear iterative equation.
Microwave magnetoelectric fields: An analytical study of topological characteristics
NASA Astrophysics Data System (ADS)
Joffe, R.; Shavit, R.; Kamenetskii, E. O.
2015-10-01
The near fields originated from a small quasi-two-dimensional ferrite disk with magnetic-dipolar-mode (MDM) oscillations are the fields with broken dual (electric-magnetic) symmetry. Numerical studies show that such fields - called the magnetoelectric (ME) fields - are distinguished by the power-flow vortices and helicity parameters (E.O. Kamenetskii, R. Joffe, R. Shavit, Phys. Rev. E 87 (2013) 023201). These numerical studies can well explain recent experimental results with MDM ferrite disks. In the present paper, we obtain analytically topological characteristics of the ME-field modes. For this purpose, we used a method of successive approximations. In the second approximation we take into account the influence of the edge regions of an open ferrite disk, which are excluded in the first-approximation solving of the magnetostatic (MS) spectral problem. Based on the analytical method, we obtain a "pure" structure of the electric and magnetic fields outside the MDM ferrite disk. The analytical studies can display some fundamental features that are non-observable in the numerical results. While in numerical investigations, one cannot separate the ME fields from the external electromagnetic (EM) radiation, the present theoretical analysis allows clearly distinguish the eigen topological structure of the ME fields. Importantly, this ME-field structure gives evidence for certain phenomena that can be related to the Tellegen and bianisotropic coupling effects. We discuss the question whether the MDM ferrite disk can exhibit properties of the cross magnetoelectric polarizabilities.
Analytic semigroups: Applications to inverse problems for flexible structures
NASA Technical Reports Server (NTRS)
Banks, H. T.; Rebnord, D. A.
1990-01-01
Convergence and stability results for least squares inverse problems involving systems described by analytic semigroups are presented. The practical importance of these results is demonstrated by application to several examples from problems of estimation of material parameters in flexible structures using accelerometer data.
Problem Solving, Reasoning, and Analytical Thinking in a Classroom Environment
ERIC Educational Resources Information Center
Robbins, Joanne K.
2011-01-01
Problem solving, reasoning, and analytical thinking are defined and described as teachable repertoires. This paper describes work performed at a school serving special needs children, Morningside Academy, that has resulted in specific procedures developed over the past 15 years. These procedures include modifying "Think Aloud Pair Problem Solving"…
Analytic formulas for magnetron characteristic curves
Riyopoulos, S.
1995-12-31
A closed non-linear set of equations is obtained based on the guiding center fluid model to describe steady-state magnetron operation. Spoke charge effects are included self-consistently, by introducing a mean-field approximation so that the effective AC potential preserves the geometric similarity with the vacuum solutions. New characteristic equations, relating the anode current 1 and the RF power P to the applied DC voltage V at given RF frequency, are obtained. Previously obtained V-I equations disagree with experiments in that (a) anode current and RF power go to zero when the resonance condition V = V{sub s} is met, (b) the operation voltage V is a double-valued function of the current I; there exist two nearly symmetric operation points around V{sub s} at the same current I. Yet magnetrons, and the related crossed-field amplifiers, are known to exhibit stable operation with single valued V-I characteristics well below V{sub s}. Although zero gain at synchronism applies to other microwave devices (TWT`s, FEL`s), experimental results and particle simulations of crossed field devices suggest otherwise. The new formulas show reasonable agreement with experiments.
The limited relevance of analytical ethics to the problems of bioethics.
Holmes, R L
1990-04-01
Philosophical ethics comprises metaethics, normative ethics and applied ethics. These have characteristically received analytic treatment by twentieth-century Anglo-American philosophy. But there has been disagreement over their interrelationship to one another and the relationship of analytical ethics to substantive morality--the making of moral judgments. I contend that the expertise philosophers have in either theoretical or applied ethics does not equip them to make sounder moral judgments on the problems of bioethics than nonphilosophers. One cannot "apply" theories like Kantianism or consequentialism to get solutions to practical moral problems unless one knows which theory is correct, and that is a metaethical question over which there is no consensus. On the other hand, to presume to be able to reach solutions through neutral analysis of problems is unavoidably to beg controversial theoretical issues in the process. Thus, while analytical ethics can play an important clarificatory role in bioethics, it can neither provide, nor substitute for, moral wisdom. PMID:2351891
An analytically solvable eigenvalue problem for the linear elasticity equations.
Day, David Minot; Romero, Louis Anthony
2004-07-01
Analytic solutions are useful for code verification. Structural vibration codes approximate solutions to the eigenvalue problem for the linear elasticity equations (Navier's equations). Unfortunately the verification method of 'manufactured solutions' does not apply to vibration problems. Verification books (for example [2]) tabulate a few of the lowest modes, but are not useful for computations of large numbers of modes. A closed form solution is presented here for all the eigenvalues and eigenfunctions for a cuboid solid with isotropic material properties. The boundary conditions correspond physically to a greased wall.
Problems encountered during impact calculations using analytic equations of state
Kerrisk, J.F.; Harvey, W.B.
1997-02-01
During modeling of the impact of a projectile on a target or other calculations that bring materials together at high velocities, computer simulations of materials being shocked to high pressure and then releasing to low pressure are performed. Depending on the circumstances, the release to low pressure is often accompanied by release to a very low density. Numerical problems leading to very large sound speeds (and thus small time steps) or to negative Lagrangian volumes have been encountered during MESA-2D calculations of this nature. These problems can be traced to the behavior of the equation of state (EOS) in the limit as the density becomes much less than the normal or reference density. Although analytic solutions for expansion isentropes may show acceptable behavior in the low-density limit, numerical solutions can show undesirable behavior. Examples of this undesirable behavior in the low-density regime are given for some simple, analytic equations of state that have closed-form solutions for isentropes. The behavior of three analytic EOSs that are frequently used in MESA-2D calculations are then discussed. These EOSs are the Los Alamos EOS, the MESA polynomial EOS, and a Mie-Gruneisen EOS based on a linear relation between shock and particle velocity. The problems in the low-density region can be corrected for the Los Alamos EOS and the MESA polynomial EOS by the proper choice of EOS coefficients in the expansion region (density less than the reference density). Problems with the Mie-Gruneisen EOS can be corrected if the functional relationship between the Gruneisen parameter ({Tau}) and density differs above and below the reference density.
Does incubation enhance problem solving? A meta-analytic review.
Sio, Ut Na; Ormerod, Thomas C
2009-01-01
A meta-analytic review of empirical studies that have investigated incubation effects on problem solving is reported. Although some researchers have reported increased solution rates after an incubation period (i.e., a period of time in which a problem is set aside prior to further attempts to solve), others have failed to find effects. The analysis examined the contributions of moderators such as problem type, presence of solution-relevant or misleading cues, and lengths of preparation and incubation periods to incubation effect sizes. The authors identified a positive incubation effect, with divergent thinking tasks benefiting more than linguistic and visual insight tasks from incubation. Longer preparation periods gave a greater incubation effect, whereas filling an incubation period with high cognitive demand tasks gave a smaller incubation effect. Surprisingly, low cognitive demand tasks yielded a stronger incubation effect than did rest during an incubation period when solving linguistic insight problems. The existence of multiple types of incubation effect provides evidence for differential invocation of knowledge-based vs. strategic solution processes across different classes of problem, and it suggests that the conditions under which incubation can be used as a practical technique for enhancing problem solving must be designed with care. PMID:19210055
Analytical solution of the bosonic three-body problem.
Gogolin, Alexander O; Mora, Christophe; Egger, Reinhold
2008-04-11
We revisit the problem of three identical bosons in free space, which exhibits a universal hierarchy of bound states (Efimov trimers). Modeling a narrow Feshbach resonance within a two-channel description, we map the integral equation for the three-body scattering amplitude to a one-dimensional Schrödinger-type single-particle equation, where an analytical solution of exponential accuracy is obtained. We give exact results for the trimer binding energies, the three-body parameter, the threshold to the three-atom continuum, and the recombination rate. PMID:18518009
Trentacosta, Christopher J.; Fine, Sarah E.
2010-01-01
The present meta-analytic review examined the magnitude of the relation between discrete emotion knowledge and three of its most commonly studied correlates in childhood and adolescence: social competence, internalizing problems, and externalizing problems. Emotion knowledge demonstrated small to medium-sized relations with each correlate. Moderators of effect size were also examined and included multiple sample and methodological characteristics. Using random effects models, significant moderators of effect size for relations between emotion knowledge and externalizing problems included sample recruitment, sample age, and the source of externalizing problems ratings. Moderators of effect size were not found for emotion knowledge and social competence, and the effect sizes across samples for emotion knowledge and internalizing problems were homogeneous. Results highlight the relatively consistent yet modest relations between emotion knowledge and its correlates. Implications for applied research and new directions for research on emotion knowledge using innovative methods are discussed. PMID:21072259
Kramers problem: Numerical Wiener-Hopf-like model characteristics
NASA Astrophysics Data System (ADS)
Ezin, A. N.; Samgin, A. L.
2010-11-01
Since the Kramers problem cannot be, in general, solved in terms of elementary functions, various numerical techniques or approximate methods must be employed. We present a study of characteristics for a particle in a damped well, which can be considered as a discretized version of the Melnikov [Phys. Rev. E 48, 3271 (1993)]10.1103/PhysRevE.48.3271 turnover theory. The main goal is to justify the direct computational scheme to the basic Wiener-Hopf model. In contrast to the Melnikov approach, which implements factorization through a Cauchy-theorem-based formulation, we employ the Wiener-Levy theorem to reduce the Kramers problem to a Wiener-Hopf sum equation written in terms of Toeplitz matrices. This latter can provide a stringent test for the reliability of analytic approximations for energy distribution functions occurring in the Kramers problems at arbitrary damping. For certain conditions, the simulated characteristics are compared well with those determined using the conventional Fourier-integral formulas, but sometimes may differ slightly depending on the value of a dissipation parameter. Another important feature is that, with our method, we can avoid some complications inherent to the Melnikov method. The calculational technique reported in the present paper may gain particular importance in situations where the energy losses of the particle to the bath are a complex-shaped function of the particle energy and analytic solutions of desired accuracy are not at hand. In order to appreciate more readily the significance and scope of the present numerical approach, we also discuss concrete aspects relating to the field of superionic conductors.
Kramers problem: numerical Wiener-Hopf-like model characteristics.
Ezin, A N; Samgin, A L
2010-11-01
Since the Kramers problem cannot be, in general, solved in terms of elementary functions, various numerical techniques or approximate methods must be employed. We present a study of characteristics for a particle in a damped well, which can be considered as a discretized version of the Melnikov [Phys. Rev. E 48, 3271 (1993)] turnover theory. The main goal is to justify the direct computational scheme to the basic Wiener-Hopf model. In contrast to the Melnikov approach, which implements factorization through a Cauchy-theorem-based formulation, we employ the Wiener-Levy theorem to reduce the Kramers problem to a Wiener-Hopf sum equation written in terms of Toeplitz matrices. This latter can provide a stringent test for the reliability of analytic approximations for energy distribution functions occurring in the Kramers problems at arbitrary damping. For certain conditions, the simulated characteristics are compared well with those determined using the conventional Fourier-integral formulas, but sometimes may differ slightly depending on the value of a dissipation parameter. Another important feature is that, with our method, we can avoid some complications inherent to the Melnikov method. The calculational technique reported in the present paper may gain particular importance in situations where the energy losses of the particle to the bath are a complex-shaped function of the particle energy and analytic solutions of desired accuracy are not at hand. In order to appreciate more readily the significance and scope of the present numerical approach, we also discuss concrete aspects relating to the field of superionic conductors. PMID:21230615
Analytic model and frequency characteristics of plasma synthetic jet actuator
NASA Astrophysics Data System (ADS)
Zong, Hao-hua; Wu, Yun; Li, Ying-hong; Song, Hui-min; Zhang, Zhi-bo; Jia, Min
2015-02-01
This paper reports a novel analytic model of a plasma synthetic jet actuator (PSJA), considering both the heat transfer effect and the inertia of the throat gas. Both the whole cycle characteristics and the repetitive working process of PSJA can be predicted with this model. The frequency characteristics of a PSJA with 87 mm3 volume and different orifice diameters are investigated based on the analytic model combined with experiments. In the repetitive working mode, the actuator works initially in the transitional stage with 20 cycles and then in the dynamic balanced stage. During the transitional stage, major performance parameters of PSJA experience stepped growth, while during the dynamic balanced stage, these parameters are characterized by periodic variation. With a constant discharge energy of 6.9 mJ, there exists a saturated frequency of 4 kHz/6 kHz for an orifice diameter of 1 mm/1.5 mm, at which the time-averaged total pressure of the pulsed jet reaches a maximum. Between 0.5 mm and 1.5 mm, a larger orifice diameter leads to a higher saturated frequency due to the reduced jet duration time. As the actuation frequency increases, both the time-averaged cavity temperature and the peak jet velocity initially increase and then remain almost unchanged at 1600 K and 280 m/s, respectively. Besides, with increasing frequency, the mechanical energy incorporated in single pulsed jet, the expelled mass per pulse, and the time-averaged density in the cavity, decline in a stair stepping way, which is caused by the intermittent decrease of refresh stage duration in one period.
Konovalov, Aleksandr B; Vlasov, V V; Kalintsev, A G; Lyubimov, Vladimir V; Kravtsenyuk, Olga V
2006-11-30
The inverse problem of diffuse optical tomography (DOT) is reduced by the method of photon average trajectories (PAT) to the solution of the integral equation integrated along the conditional mean statistical photon trajectory. The PAT bending near the flat boundary of a scattering medium is estimated analytically. These estimates are used to determine the analytic statistical characteristics of photon trajectories for the flat layer geometry. The inverse DOT problem is solved by using the multiplicative algebraic algorithm modified to improve the convergence of the iteration reconstruction process. The numerical experiment shows that the modified PAT method permits the reconstruction of near-surface optical inhomogeneities virtually without distortions. (special issue devoted to multiple radiation scattering in random media)
Analytical and Numerical Studies of Several Fluid Mechanical Problems
NASA Astrophysics Data System (ADS)
Kong, D. L.
2014-03-01
In this thesis, three parts, each with several chapters, are respectively devoted to hydrostatic, viscous, and inertial fluids theories and applications. Involved topics include planetary, biological fluid systems, and high performance computing technology. In the hydrostatics part, the classical Maclaurin spheroids theory is generalized, for the first time, to a more realistic multi-layer model, establishing geometries of both the outer surface and the interfaces. For one of its astrophysical applications, the theory explicitly predicts physical shapes of surface and core-mantle-boundary for layered terrestrial planets, which enables the studies of some gravity problems, and the direct numerical simulations of dynamo flows in rotating planetary cores. As another application of the figure theory, the zonal flow in the deep atmosphere of Jupiter is investigated for a better understanding of the Jovian gravity field. An upper bound of gravity field distortions, especially in higher-order zonal gravitational coefficients, induced by deep zonal winds is estimated firstly. The oblate spheroidal shape of an undistorted Jupiter resulting from its fast solid body rotation is fully taken into account, which marks the most significant improvement from previous approximation based Jovian wind theories. High viscosity flows, for example Stokes flows, occur in a lot of processes involving low-speed motions in fluids. Microorganism swimming is such a typical case. A fully three dimensional analytic solution of incompressible Stokes equation is derived in the exterior domain of an arbitrarily translating and rotating prolate spheroid, which models a large family of microorganisms such as cocci bacteria. The solution is then applied to the magnetotactic bacteria swimming problem, and good consistency has been found between theoretical predictions and laboratory observations of the moving patterns of such bacteria under magnetic fields. In the analysis of dynamics of planetary
Characteristics of Problems for Problem-Based Learning: The Students' Perspective
ERIC Educational Resources Information Center
Sockalingam, Nachamma; Schmidt, Henk G.
2011-01-01
This study aimed to identify salient problem characteristics perceived by students in problem-based curricula. To this end, reflective essays from biomedical students (N = 34) on characteristics of good problems were text-analyzed. Students identified eleven characteristics, of which they found the extent to which the problem leads to desired…
Semi-analytic approach for electromagnetic problems of large arrays structures
NASA Astrophysics Data System (ADS)
Rostami-Angas, Masoud
There are limited electromagnetic problems which have closed form analytic solutions. Most of the real-world electromagnetic problems like electromagnetic scattering, electromagnetic radiation, waveguide modeling, etc., are not analytically calculable, because of the multitude of irregular geometries found in actual devices. Numerical computational techniques can be used as alternative method to overcome the inability of deriving closed form solutions of Maxwell's equations under various constitutive relations of media, and boundary conditions. This makes computational electromagnetics important in microwave, RF and photonic areas. Care must be taken into choosing the right method; otherwise the wrong method can either yield incorrect results, or results which take excessively long or demand great computational resources. Moreover, there are important electromagnetic problems for which numerical method solutions are challenging, if not impossible. Large non-periodic array of dipoles and multilayer spheres are examples of those problems. Some of these problems, because of their specific geometries and characteristics, can be modeled accurately and efficiently by applying Discrete Dipole Approximation (DDA), multipole expansion and translation addition theorem. The usual solution approach is to model the electromagnetic fields, or other unknowns, using multipole expansions, truncate appropriately the infinite summations, apply the boundary conditions, and then solve the resulting matrix problem by numerical methods. Because the approach contains both of analytic methods and numerical matrix solvers, it can be considered as a semi-analytic approach. The first chapter briefly describes the electromagnetic problems and semi-analytic approaches of this thesis. In the second chapter, a large array of molecular aggregates is investigated with the goal of solving the multiscale problem of a large array of molecules to explore its optical behaviors. Quantum electrodynamics
Asbestos quantification in track ballast, a complex analytical problem
NASA Astrophysics Data System (ADS)
Cavallo, Alessandro
2016-04-01
Track ballast forms the trackbeb upon which railroad ties are laid. It is used to bear the load from the railroad ties, to facilitate water drainage, and also to keep down vegetation. It is typically made of angular crushed stone, with a grain size between 30 and 60 mm, with good mechanical properties (high compressive strength, freeze - thaw resistance, resistance to fragmentation). The most common rock types are represented by basalts, porphyries, orthogneisses, some carbonatic rocks and "green stones" (serpentinites, prasinites, amphibolites, metagabbros). Especially "green stones" may contain traces, and sometimes appreciable amounts of asbestiform minerals (chrysotile and/or fibrous amphiboles, generally tremolite - actinolite). In Italy, the chrysotile asbestos mine in Balangero (Turin) produced over 5 Mt railroad ballast (crushed serpentinites), which was used for the railways in northern and central Italy, from 1930 up to 1990. In addition to Balangero, several other serpentinite and prasinite quarries (e.g. Emilia Romagna) provided the railways ballast up to the year 2000. The legal threshold for asbestos content in track ballast is established in 1000 ppm: if the value is below this threshold, the material can be reused, otherwise it must be disposed of as hazardous waste, with very high costs. The quantitative asbestos determination in rocks is a very complex analytical issue: although techniques like TEM-SAED and micro-Raman are very effective in the identification of asbestos minerals, a quantitative determination on bulk materials is almost impossible or really expensive and time consuming. Another problem is represented by the discrimination of asbestiform minerals (e.g. chrysotile, asbestiform amphiboles) from the common acicular - pseudo-fibrous varieties (lamellar serpentine minerals, prismatic/acicular amphiboles). In this work, more than 200 samples from the main Italian rail yards were characterized by a combined use of XRD and a special SEM
Overview of tritium: characteristics, sources, and problems.
Okada, S; Momoshima, N
1993-12-01
Tritium has certain characteristics that present unique challenges for dosimetry and health-risk assessment. For example, in the gas form, tritium can diffuse through almost any container, including those made of steel, aluminum, and plastics. In the oxide form, tritium can generally not be detected by commonly used survey instruments. In the environment, tritium can be taken up by all hydrogen-containing molecules, distributing widely on a global scale. Tritium can be incorporated into humans through respiration, ingestion, and diffusion through skin. Its harmful effects are observed only when it is incorporated into the body. Several sources contribute to the inventory of tritium in our environment. These are 1) cosmic ray interaction with atmospheric molecules; 2) nuclear reactions in the earth's crust; 3) nuclear testing in the atmosphere during the 1950s and 1960s; 4) continuous release of tritium from nuclear power plants and tritium production facilities under normal operation; 5) incidental releases from these facilities; and 6) consumer products. An important future source will be nuclear fusion facilities expected to be developed for the purpose of electricity generation. The principal health physics problems associated with tritium are 1) the determination of the parameters for risk estimation with further reduction of their uncertainties (e.g., relative biological effectiveness and dose-rate dependency); 2) risk estimation from complex exposures to tritium in gas form, tritium in oxide form, tritium surface contamination, and other tritium-contaminated forms, with or without other ionizing radiations and/or nonionizing radiations; 3) the dose contributions of elemental tritium in the lung and from its oxidized tritium in the gastrointestinal tract; 4) prevention of tritium (in oxide form) intake and enhancement of tritium (oxide form) excretion from the human body; 5) precise health effects information for low-level tritium exposure; and 6) public
Analytical Solution to the Riemann Problem of Three-Phase Flow in Porous Media
Juanes, Ruben; Patzek, Tadeusz W.
2002-09-26
In this paper we study one-dimensional three-phase flow through porous media of immiscible, incompressible fluids. The model uses the common multiphase flow extension of Darcy's equation, and does not include gravity and capillarity effects. Under these conditions, the mathematical problem reduces to a 2 x 2 system of conservation laws whose essential features are: (1) the system is strictly hyperbolic; (2) both characteristic fields are nongenuinely nonlinear, with single, connected inflection loci. These properties, which are natural extensions of the two-phase flow model, ensure that the solution is physically sensible. We present the complete analytical solution to the Riemann problem (constant initial and injected states) in detail, and describe the characteristic waves that may arise, concluding that only nine combinations of rarefactions, shocks and rarefaction-shocks are possible. We demonstrate that assuming the saturation paths of the solution are straightlines may result in inaccurate predictions for some realistic systems. Efficient algorithms for computing the exact solution are also given, making the analytical developments presented here readily applicable to interpretation of lab displacement experiments, and implementation of streamline simulators.
Nanomaterials in consumer products: a challenging analytical problem.
Contado, Catia
2015-01-01
Many products used in everyday life are made with the assistance of nanotechnologies. Cosmetic, pharmaceuticals, sunscreen, powdered food are only few examples of end products containing nano-sized particles (NPs), generally added to improve the product quality. To evaluate correctly benefits vs. risks of engineered nanomaterials and consequently to legislate in favor of consumer's protection, it is necessary to know the hazards connected with the exposure levels. This information implies transversal studies and a number of different competences. On analytical point of view the identification, quantification and characterization of NPs in food matrices and in cosmetic or personal care products pose significant challenges, because NPs are usually present at low concentration levels and the matrices, in which they are dispersed, are complexes and often incompatible with analytical instruments that would be required for their detection and characterization. This paper focused on some analytical techniques suitable for the detection, characterization and quantification of NPs in food and cosmetics products, reports their recent application in characterizing specific metal and metal-oxide NPs in these two important industrial and market sectors. The need of a characterization of the NPs as much as possible complete, matching complementary information about different metrics, possible achieved through validate procedures, is what clearly emerges from this research. More work should be done to produce standardized materials and to set-up methodologies to determine number-based size distributions and to get quantitative date about the NPs in such a complex matrices. PMID:26301216
Nanomaterials in consumer products: a challenging analytical problem
NASA Astrophysics Data System (ADS)
Contado, Catia
2015-08-01
Many products used in everyday life are made with the assistance of nanotechnologies. Cosmetic, pharmaceuticals, sunscreen, powdered food are only few examples of end products containing nano-sized particles (NPs), generally added to improve the product quality. To evaluate correctly benefits versus risks of engineered nanomaterials and consequently to legislate in favor of consumer’s protection, it is necessary to know the hazards connected with the exposure levels. This information implies transversal studies and a number of different competences. On analytical point of view the identification, quantification and characterization of NPs in food matrices and in cosmetic or personal care products pose significant challenges, because NPs are usually present at low concentration levels and the matrices, in which they are dispersed, are complexes and often incompatible with analytical instruments that would be required for their detection and characterization. This paper focused on some analytical techniques suitable for the detection, characterization and quantification of NPs in food and cosmetics products, reports their recent application in characterizing specific metal and metal-oxide NPs in these two important industrial and market sectors. The need of a characterization of the NPs as much as possible complete, matching complementary information about different metrics, possible achieved through validate procedures, is what clearly emerges from this research. More work should be done to produce standardized materials and to set-up methodologies to determine number-based size distributions and to get quantitative date about the NPs in such a complex matrices.
Nanomaterials in consumer products: a challenging analytical problem
Contado, Catia
2015-01-01
Many products used in everyday life are made with the assistance of nanotechnologies. Cosmetic, pharmaceuticals, sunscreen, powdered food are only few examples of end products containing nano-sized particles (NPs), generally added to improve the product quality. To evaluate correctly benefits vs. risks of engineered nanomaterials and consequently to legislate in favor of consumer's protection, it is necessary to know the hazards connected with the exposure levels. This information implies transversal studies and a number of different competences. On analytical point of view the identification, quantification and characterization of NPs in food matrices and in cosmetic or personal care products pose significant challenges, because NPs are usually present at low concentration levels and the matrices, in which they are dispersed, are complexes and often incompatible with analytical instruments that would be required for their detection and characterization. This paper focused on some analytical techniques suitable for the detection, characterization and quantification of NPs in food and cosmetics products, reports their recent application in characterizing specific metal and metal-oxide NPs in these two important industrial and market sectors. The need of a characterization of the NPs as much as possible complete, matching complementary information about different metrics, possible achieved through validate procedures, is what clearly emerges from this research. More work should be done to produce standardized materials and to set-up methodologies to determine number-based size distributions and to get quantitative date about the NPs in such a complex matrices. PMID:26301216
Constructive analytical solution of the evolution hill problem
NASA Astrophysics Data System (ADS)
Vashkov'yak, M. A.
2010-12-01
A new analytical solution of the system of differential equations describing secular perturbations and long-period solar perturbations of mean orbits of outer satellites of giant planets was obtained. As distinct from other solutions, the solution constructed using von Zeipel's method approximately takes into account, in the secular part of the perturbing function, the totality of fourth order with respect to the small parameter m of the ratio of the mean motions of the primary planet and the satellite. This enables us to describe more accurately the evolution of satellite orbits with large apocentric distances, which in the course of evolution may exceed the halved radius of the Hill sphere of the planet with respect to the Sun. Among these are the orbits of the two outermost Neptunian satellites N10 (Psamathe) and N13 (Neso). For these satellites, the parameter m amounts to 0.152 and 0.165, respectively. Different from a purely analytical solution, the proposed solution requires preliminary calculations for each satellite. More precisely, in doing so, we need to construct some simple functions to approximate more complex ones. This is why we use the phrase "constructive analytical." To illustrate the solution, we compare it with the results of the numerical integration of the strict motion equations of the satellites N10 and N13 over time intervals 5-15 thousand years.
Three-body quantum Coulomb problem: Analytic continuation
NASA Astrophysics Data System (ADS)
Turbiner, A. V.; Lopez Vieyra, J. C.; Olivares Pilón, H.
2016-08-01
The second (unphysical) critical charge in the three-body quantum Coulomb system of a nucleus of positive charge Z and mass mp, and two electrons, predicted by Stillinger has been calculated to be equal to ZB∞ = 0.904854 and ZBmp = 0.905138 for infinite and finite (proton) mass mp, respectively. It is shown that in both cases, the ground state energy E(Z) (analytically continued beyond the first critical charge Zc, for which the ionization energy vanishes, to ReZ
An analytical solution for the swing-by problem
NASA Astrophysics Data System (ADS)
Valsecchi, G. B.; Alessi, E. M.; Rossi, A.
2015-10-01
The extension of Öpik's theory of close encounters developed in the last decades allows a fully analytical, quantitative treatment of the motion of a small body encountering a massive perturber on a circular orbit. In this paper we derive explicit expressions for the initial values of the angular elements of the small body orbit, of given semimajor axis, eccentricity and inclination, in order to obtain a post-encounter orbit with prescribed values of semimajor axis, eccentricity and inclination. We describe the geometrical aspects of the algorithm, and give two examples of application; the first of them concerns the geometry of the 2029 Earth encounter of Apophis, while the second illustrates a sequence of close encounters with Callisto of the JUICE probe, aimed at changing the inclination of the spacecraft orbit. In the planning of complex space missions involving multiple encounters with planets or satellites, the algorithm described in the paper could provide a reliable initial guess to start the computationally intensive optimization process.
An analytical treatment of the swing-by problem.
NASA Astrophysics Data System (ADS)
Valsecchi, G. B.; Alessi, E. M.; Rossi, A.
In the framework of the extension of Öpik's theory of close encounters developed in the last decades, we make a fully analytical, quantitative treatment of the motion of a small body encountering a massive perturber on a circular orbit (Valsecchi et al. 2015a,b). We derive explicit expressions for the initial values of the angular elements of a small body orbit, of given semimajor axis a, eccentricity e, and inclination i, that are needed in order to obtain a post-encounter orbit with prescribed values of semimajor axis a', eccentricity e', and inclination i'. We discuss the geometrical aspects of the algorithm, and give two examples of application; the first one deals with the geometry of the 2029 Earth encounter of Apophis, while the second illustrates a sequence of close encounters with Callisto of the JUICE probe, aimed at changing the inclination of the spacecraft orbit. In planning complex space missions involving multiple encounters with planets or satellites, the algorithm described here could provide a reliable initial guess to start the computationally intensive optimization process.
An analytic method for the inverse problem of MREPT
NASA Astrophysics Data System (ADS)
Palamodov, V.
2016-03-01
Magnetic resonance electric properties tomography (MREPT) is a medical imaging modality for visualizing the electrical tissue properties of the human body using radio-frequency magnetic fields. This method consists of reconstructing the admittivity distribution from the positive rotating component of the magnetic field. In the newest paper of Ammari et al (2015 Inverse Problems 31 105001) an approximate method of reconstruction of variable admittivity was proposed. In this paper a method for exact reconstruction of the admittivity from data of the positive rotating component of the field is given.
ERIC Educational Resources Information Center
Cancilla, Devon A.
2001-01-01
Introduces an undergraduate level problem-based analytical chemistry laboratory course integrated with an environmental law course. Aims to develop an understanding among students on the use of environmental indicators for environmental evaluation. (Contains 30 references.) (YDS)
The "PIP problem": clinical and histologic characteristics.
Correia-Sá, Inês; Rodrigues-Pereira, Pedro; Marques, Marisa
2013-10-01
Implants from Poly Implant Prothése (PIP), the French manufacturer, showed increased risk of implant rupture and silicone leakage through the shell. Concerns also exist about the potential irritant behavior of silicone gel filler in these implants. This report presents the clinical, histologic, and microbiologic characteristics of a capsule and a siliconoma from a patient with a ruptured PIP implant. A 41-year-old woman submitted to breast augmentation in 2005 with PIP silicone gel implants presented with a recent history of progressive asymmetric breast enlargement and an enlarged lymph node on her right axilla. No capsular contracture was observed. A breast ultrasonography showed intra- and extracapsular ruptures of the right implant. The woman underwent explantation. Histologic analysis of the breast capsules showed a thin capsule with a chronic, mild inflammatory response. Microbiologic analysis showed no bacterial agent. The irritant behavior of the PIP silicone gel previously described was not able to produce capsular contracture or an exuberant inflammatory reaction. Studies to evaluate the potential risks of the silicone gel and to define the hazards for women implanted with those prostheses are urgently needed. PMID:23943050
NASA Astrophysics Data System (ADS)
Duffy, Brenton
The distinguishing characteristic of the elliptic restricted three-body problem from that of the circular case is a pulsating potential field resulting in non-autonomous and non-integrable spacecraft dynamics, which are difficult to model using classical methods of analysis. The purpose of this study is to harness modern methods of analytical perturbation theory to normalize the system dynamics about the circular restricted three-body problem and about one of the triangular Lagrange points. The normalization is achieved through a canonical transformation of the system Hamiltonian function based on the Lie transform method introduced by Hori and Deprit in the 1960s. The classic method derives a near-identity transformation of a Hamiltonian function expanded about a single parameter such that the transformed system possesses ideal properties of integrability. One of the major contributions of this study is to extend the normalization method to two-parameter expansions and to non-autonomous Hamiltonian systems. The two-parameter extension is used to normalize the system dynamics of the elliptic restricted three-body problem such that the stability of the triangular Lagrange points may be determined using the Kolmogorov-Arnold-Moser theorem. Further dynamical analysis is performed in the transformed phase space in terms of local integrals of motion akin to Jacobi's integral of the circular restricted three-body problem. The local phase space around the Lagrange point is foliated by invariant tori that effectively separate the planar dynamics into qualitative regions of motion. Additional analysis is presented for the incorporation of control into the normalization routine with the goal of eliminating the non-circular secular perturbations. The control method is validated on a test case and applied to the elliptic restricted three-body problem for the purposes of stabilizing the motion around the triangular Lagrange points.
Analytical derivation: An epistemic game for solving mathematically based physics problems
NASA Astrophysics Data System (ADS)
Bajracharya, Rabindra R.; Thompson, John R.
2016-06-01
Problem solving, which often involves multiple steps, is an integral part of physics learning and teaching. Using the perspective of the epistemic game, we documented a specific game that is commonly pursued by students while solving mathematically based physics problems: the analytical derivation game. This game involves deriving an equation through symbolic manipulations and routine mathematical operations, usually without any physical interpretation of the processes. This game often creates cognitive obstacles in students, preventing them from using alternative resources or better approaches during problem solving. We conducted hour-long, semi-structured, individual interviews with fourteen introductory physics students. Students were asked to solve four "pseudophysics" problems containing algebraic and graphical representations. The problems required the application of the fundamental theorem of calculus (FTC), which is one of the most frequently used mathematical concepts in physics problem solving. We show that the analytical derivation game is necessary, but not sufficient, to solve mathematically based physics problems, specifically those involving graphical representations.
The Contributions of Spatial, Verbal, and Analytical Skills to Problem-Solving Performance
ERIC Educational Resources Information Center
Foster, Ardyth C.
2012-01-01
The purpose of this study was to examine the existence and strength of relationships between students' cognitive skills and mathematical problem-solving performance. Specifically, relationships between students' verbal, spatial, and analytical skills and their problem-solving performance on items that require a verbal response, items…
ERIC Educational Resources Information Center
Pardue, Harry L.; Woo, Jannie
1984-01-01
Proposes an approach to teaching analytical chemistry and chemical analysis in which a problem to be resolved is the focus of a course. Indicates that this problem-oriented approach is intended to complement detailed discussions of fundamental and applied aspects of chemical determinations and not replace such discussions. (JN)
Analytical Derivation: An Epistemic Game for Solving Mathematically Based Physics Problems
ERIC Educational Resources Information Center
Bajracharya, Rabindra R.; Thompson, John R.
2016-01-01
Problem solving, which often involves multiple steps, is an integral part of physics learning and teaching. Using the perspective of the epistemic game, we documented a specific game that is commonly pursued by students while solving mathematically based physics problems: the "analytical derivation" game. This game involves deriving an…
The finite time multi-level SU(2) Landau-Zener problems: exact analytical results
NASA Astrophysics Data System (ADS)
Mkam Tchouobiap, S. E.; Kenmoe, M. B.; Fai, L. C.
2015-10-01
The multi-level SU(2) Landau-Zener problem is analytically solved at finite time within the framework of the Bloch tensor formalism and with the help of the disentanglement Wei-Norman ordering technique. A generalized and exact analytical solution is achieved that accounts not only for all projections of an arbitrary spin S along the Zeeman field direction but also for non-adiabatic and adiabatic evolutions.
An analytical procedure for evaluating shuttle abort staging aerodynamic characteristics
NASA Technical Reports Server (NTRS)
Meyer, R.
1973-01-01
An engineering analysis and computer code (AERSEP) for predicting Space Shuttle Orbiter - HO Tank longitudinal aerodynamic characteristics during abort separation has been developed. Computed results are applicable at Mach numbers above 2 for angle-of-attack between plus or minus 10 degrees. No practical restrictions on orbiter-tank relative positioning are indicated for tank-under-orbiter configurations. Input data requirements and computer running times are minimal facilitating program use for parametric studies, test planning, and trajectory analysis. In a majority of cases AERSEP Orbiter-Tank interference predictions are as accurate as state-of-the-art estimates for interference-free or isolated-vehicle configurations. AERSEP isolated-orbiter predictions also show excellent correlation with data.
NASA Astrophysics Data System (ADS)
Zingerman, K. M.; Shavyrin, D. A.
2016-06-01
The approximate analytical solution of a quasi-static plane problem of the theory of viscoelasticity is obtained under finite strains. This is the problem of the stress-strain state in an infinite body with circular viscoelastic inclusion. The perturbation technique, Laplace transform, and complex Kolosov-Muskhelishvili's potentials are used for the solution. The numerical results are presented. The nonlinear effects and the effects of viscosity are estimated.
Analytical solution of boundary integral equations for 2-D steady linear wave problems
NASA Astrophysics Data System (ADS)
Chuang, J. M.
2005-10-01
Based on the Fourier transform, the analytical solution of boundary integral equations formulated for the complex velocity of a 2-D steady linear surface flow is derived. It has been found that before the radiation condition is imposed, free waves appear both far upstream and downstream. In order to cancel the free waves in far upstream regions, the eigensolution of a specific eigenvalue, which satisfies the homogeneous boundary integral equation, is found and superposed to the analytical solution. An example, a submerged vortex, is used to demonstrate the derived analytical solution. Furthermore, an analytical approach to imposing the radiation condition in the numerical solution of boundary integral equations for 2-D steady linear wave problems is proposed.
Li, Rui; Wang, Pengcheng; Tian, Yu; Wang, Bo; Li, Gang
2015-01-01
A unified analytic solution approach to both static bending and free vibration problems of rectangular thin plates is demonstrated in this paper, with focus on the application to corner-supported plates. The solution procedure is based on a novel symplectic superposition method, which transforms the problems into the Hamiltonian system and yields accurate enough results via step-by-step rigorous derivation. The main advantage of the developed approach is its wide applicability since no trial solutions are needed in the analysis, which is completely different from the other methods. Numerical examples for both static bending and free vibration plates are presented to validate the developed analytic solutions and to offer new numerical results. The approach is expected to serve as a benchmark analytic approach due to its effectiveness and accuracy. PMID:26608602
ERIC Educational Resources Information Center
Boyce, Mary C.; Singh, Kuki
2008-01-01
This paper describes a student-focused activity that promotes effective learning in analytical chemistry. Providing an environment where students were responsible for their own learning allowed them to participate at all levels from designing the problem to be addressed, planning the laboratory work to support their learning, to providing evidence…
A Multilevel Analysis of Problem-Based Learning Design Characteristics
ERIC Educational Resources Information Center
Scott, Kimberly S.
2014-01-01
The increasing use of experience-centered approaches like problem-based learning (PBL) by learning and development practitioners and management educators has raised interest in how to design, implement and evaluate PBL in that field. Of particular interest is how to evaluate the relative impact of design characteristics that exist at the…
Problem Gambling in Chinese American Adolescents: Characteristics and Risk Factors
ERIC Educational Resources Information Center
Chiu, Eddie Yu-Wai; Woo, Kent
2012-01-01
This preliminary study examined the characteristics and risk factors of problem gambling among Chinese American adolescents. A total of 192 Chinese American students (aged 13-19) from 9th to 12th grades were recruited from three high schools in San Francisco, California. Students were administered the South Oaks Gambling Screen Revised for…
Client Engagement Characteristics Associated with Problem Gambling Treatment Outcomes
ERIC Educational Resources Information Center
Dowling, Nicki A.; Cosic, Sanja
2011-01-01
Previous research examining the factors associated with problem gambling treatment outcomes has examined client factors and to date, treatment characteristics, therapist factors, and client-therapist interactions have essentially remained unexplored. This study aimed to investigate how client engagement variables (client-rated therapeutic…
Fast and accurate analytical model to solve inverse problem in SHM using Lamb wave propagation
NASA Astrophysics Data System (ADS)
Poddar, Banibrata; Giurgiutiu, Victor
2016-04-01
Lamb wave propagation is at the center of attention of researchers for structural health monitoring of thin walled structures. This is due to the fact that Lamb wave modes are natural modes of wave propagation in these structures with long travel distances and without much attenuation. This brings the prospect of monitoring large structure with few sensors/actuators. However the problem of damage detection and identification is an "inverse problem" where we do not have the luxury to know the exact mathematical model of the system. On top of that the problem is more challenging due to the confounding factors of statistical variation of the material and geometric properties. Typically this problem may also be ill posed. Due to all these complexities the direct solution of the problem of damage detection and identification in SHM is impossible. Therefore an indirect method using the solution of the "forward problem" is popular for solving the "inverse problem". This requires a fast forward problem solver. Due to the complexities involved with the forward problem of scattering of Lamb waves from damages researchers rely primarily on numerical techniques such as FEM, BEM, etc. But these methods are slow and practically impossible to be used in structural health monitoring. We have developed a fast and accurate analytical forward problem solver for this purpose. This solver, CMEP (complex modes expansion and vector projection), can simulate scattering of Lamb waves from all types of damages in thin walled structures fast and accurately to assist the inverse problem solver.
Fast multigrid solution of the advection problem with closed characteristics
Yavneh, I.; Venner, C.H.; Brandt, A.
1996-12-31
The numerical solution of the advection-diffusion problem in the inviscid limit with closed characteristics is studied as a prelude to an efficient high Reynolds-number flow solver. It is demonstrated by a heuristic analysis and numerical calculations that using upstream discretization with downstream relaxation-ordering and appropriate residual weighting in a simple multigrid V cycle produces an efficient solution process. We also derive upstream finite-difference approximations to the advection operator, whose truncation terms approximate {open_quotes}physical{close_quotes} (Laplacian) viscosity, thus avoiding spurious solutions to the homogeneous problem when the artificial diffusivity dominates the physical viscosity.
A multigroup radiation diffusion test problem: Comparison of code results with analytic solution
Shestakov, A I; Harte, J A; Bolstad, J H; Offner, S R
2006-12-21
We consider a 1D, slab-symmetric test problem for the multigroup radiation diffusion and matter energy balance equations. The test simulates diffusion of energy from a hot central region. Opacities vary with the cube of the frequency and radiation emission is given by a Wien spectrum. We compare results from two LLNL codes, Raptor and Lasnex, with tabular data that define the analytic solution.
NASA Astrophysics Data System (ADS)
Kharin, Stanislav N.; Sarsengeldin, Merey M.; Nouri, Hassan
2016-08-01
On the base of the Holm model, we represent two phase spherical Stefan problem and its analytical solution, which can serve as a mathematical model for diverse thermo-physical phenomena in electrical contacts. Suggested solution is obtained from integral error function and its properties which are represented in the form of series whose coefficients have to be determined. Convergence of solution series is proved.
Psychological Characteristics of Problem Gamblers With and Without Mood Disorder
Lister, Jamey J; Milosevic, Aleks; Ledgerwood, David M
2015-01-01
Objective: Problem and pathological gamblers are significantly more likely to experience mood disorders, compared with the general population. Our study examined the relation of psychological characteristics (personality, trait impulsiveness, and gambling motives) to current co-occurring mood disorder (major depression and dysthymia) status among problem and pathological gamblers. Method: Problem and pathological gamblers (N = 150) underwent a clinical interview to assess current co-occurring mood disorders; participants completed measures of problem gambling severity, personality, impulsiveness, and gambling motives. Results: Problem and pathological gamblers with a current co-occurring mood disorder were more likely to be female, older, and to report higher lifetime and past-year gambling severity. A co-occurring mood disorder was associated with higher personality scores for alienation and stress reaction, lower scores for well-being, social closeness, and control, as well as higher impulsiveness scores for urgency and lack of premeditation, and lower sensation seeking scores. Participants with a co-occurring mood disorder also reported higher coping motives for gambling. Multivariate logistic regression analyses demonstrated that personality factors (lower social closeness and higher alienation) contributed to the greatest likelihood of being diagnosed with a co-occurring mood disorder. Conclusions: Mood disorders frequently co-occur with problem and pathological gambling, and they are associated with greater gambling severity. These findings highlight that interpersonal facets of personality contribute substantially to co-occurring mood disorder status. Implications for treatment will be discussed. PMID:26454559
Analytical solution to a fracture problem in a tough layered structure
NASA Astrophysics Data System (ADS)
Hamamoto, Yukari; Okumura, Ko
2008-08-01
Nacre causes the shining beauty of pearl due to its remarkable layered structure, which is also strong. We reconsider a simplified layered model of nacre proposed previously [Okumura and de Gennes, Eur. Phys. J. E 4, 121 (2001)] and obtain an analytical solution to a fundamental crack problem. The result asserts that the fracture toughness is enhanced due to a large displacement around the crack tip (even if the crack-tip stress is not reduced). The derivation offers ideas for solving a number of boundary problems for partial differential equations important in many fields.
NASA Technical Reports Server (NTRS)
Eberle, W. R.
1981-01-01
A computer program to calculate the wake downwind of a wind turbine was developed. Turbine wake characteristics are useful for determining optimum arrays for wind turbine farms. The analytical model is based on the characteristics of a turbulent coflowing jet with modification for the effects of atmospheric turbulence. The program calculates overall wake characteristics, wind profiles, and power recovery for a wind turbine directly in the wake of another turbine, as functions of distance downwind of the turbine. The calculation procedure is described in detail, and sample results are presented to illustrate the general behavior of the wake and the effects of principal input parameters.
Analytical techniques for the evaluation of asymptotic matrix elements in electromagnetic problems
NASA Astrophysics Data System (ADS)
Park, Seong-Ook
1997-07-01
Analytical solutions of the asymptotic part of impedance matrix elements, whose integrand contains either a singularity or exhibits a strongly oscillatory behavior, are developed for the analysis of various geometries. These developed formulas are applied using the Method of Moments (MoM), to the analysis of wire antennas, planar transmission lines, and printed circuits including microstrip dipoles, asymmetric gap discontinuities, and arbitrary shapes of planar circuits, where computational speed and accuracy are important. The first example considered is the singularity treatment in integrands of wire-type antenna problems. To overcome the problem, first the singularity is subtracted out, and then this part is integrated analytically in the transform domain. Asymptotic matrix elements of the multilayer planar transmission lines are solved analytically by using Chebyshev polynomial basis functions in the spectral domain. These results are applied to open and coupled microstrip lines. The analysis of printed circuits involves Sommerfeld-type integrals which are extremely difficult to evaluate. To enhance the speed and accuracy of Sommerfeld-type integrals, this dissertation, for the first time, presents an analytical transformation technique. This formulation allows the infinite double integral of the asymptotic part of the impedance matrix to be transformed into a finite one-dimensional integral. Using this approach, the asymptotic part of self and mutual interactions between the triangular edge mode basis functions, along an electrically narrow strip, is solved analytically. These results are applied to microstrip dipoles and asymmetric gap discontinuities. This formula provides highly accurate results with minimal computational effort. This work is also extended to roof- top subdomain basis functions, and the obtained results can be used to solve arbitrarily shaped planar geometries. As an example, computed results of the Radar Cross Section (RCS) of a microstrip
ERIC Educational Resources Information Center
Sockalingam, Nachamma; Rotgans, Jerome I.; Schmidt, Henk G.
2011-01-01
This study investigated the influence of five problem characteristics on students' achievement-related classroom behaviors and academic achievement. Data from 5,949 polytechnic students in PBL curricula across 170 courses were analyzed by means of path analysis. The five problem characteristics were: (1) problem clarity, (2) problem familiarity,…
Statistical Mechanics of a Simplified Bipartite Matching Problem: An Analytical Treatment
NASA Astrophysics Data System (ADS)
Dell'Erba, Matías Germán
2012-03-01
We perform an analytical study of a simplified bipartite matching problem in which there exists a constant matching energy, and both heterosexual and homosexual pairings are allowed. We obtain the partition function in a closed analytical form and we calculate the corresponding thermodynamic functions of this model. We conclude that the model is favored at high temperatures, for which the probabilities of heterosexual and homosexual pairs tend to become equal. In the limits of low and high temperatures, the system is extensive, however this property is lost in the general case. There exists a relation between the matching energies for which the system becomes more stable under external (thermal) perturbations. As the difference of energies between the two possible matches increases the system becomes more ordered, while the maximum of entropy is achieved when these energies are equal. In this limit, there is a first order phase transition between two phases with constant entropy.
On the dyadic scattering problem in three-dimensional gradient elasticity: an analytic approach
NASA Astrophysics Data System (ADS)
Charalambopoulos, Antonios; Gergidis, Leonidas N.
2008-10-01
The investigation of the direct scattering problem of an elastic dyadic incident field from a spherical inclusion, is the main outcome of this work, in the case where the scatterer and the host environment dispose microstructure. The framework of the method is based on the implication of Mindlin's gradient theory. The development of the method is fully analytic and gives successively several byproducts, which are indispensable for the solution of the scattering problem but constitute also independent results of their own theoretical and practical value. So the numerable set of Navier eigendyadics is constructed, which is proved to be a basis for every dyadic field obeying the dynamic gradient elasticity equation. This permits the construction of a useful spectral representation for every gradient elasticity field. Furthermore, the set of dyadic spherical harmonics is built, which stands for the extension of the well-known spherical vector harmonics to the dyadic realm. Every dyadic field restricted on the unit sphere can be expanded in terms of these spherical dyadic harmonics. The orthogonality relations of these functions are determined in close form and this is the prerequisite for the fully analytic treatment of the boundary conditions involving the scattering problem under consideration.
Complete analytical solution of electromagnetic field problem of high-speed spinning ball
NASA Astrophysics Data System (ADS)
Reichert, T.; Nussbaumer, T.; Kolar, J. W.
2012-11-01
In this article, a small sphere spinning in a rotating magnetic field is analyzed in terms of the resulting magnetic flux density distribution and the current density distribution inside the ball. From these densities, the motor torque and the eddy current losses can be calculated. An analytical model is derived, and its results are compared to a 3D finite element analysis. The model gives insight into the torque and loss characteristics of a solid rotor induction machine setup, which aims at rotating the sphere beyond 25 Mrpm.
NASA Technical Reports Server (NTRS)
Allen, J. M.
1981-01-01
Techniques to predict the aerodynamic characteristics of slender cruciform missiles have been developed and are constantly being updated and improved. This paper presents comparisons between analytical and experimental supersonic aerodynamic data for a class of canard-controlled missile configurations similar to the sidewinder missile. Three aerodynamic prediction computer codes, including program MISSILE2, a recently improved version of program MISSILE, are evaluated by comparison with the test data to assess their accuracy. The major emphasis is placed on the roll control characteristics. In addition, tail span optimization, longitudinal and lateral control, induced roll, and missile roll orientation effects are addressed.
NASA Astrophysics Data System (ADS)
Tuzkaya, Umut R.; Eser, Arzum; Argon, Goner
2004-02-01
Today, growing amounts of waste due to fast consumption rate of products started an irreversible environmental pollution and damage. A considerable part of this waste is caused by packaging material. With the realization of this fact, various waste policies have taken important steps. Here we considered a firm, where waste Aluminum constitutes majority of raw materials for this fir0m. In order to achieve a profitable recycling process, plant layout should be well designed. In this study, we propose a two-step approach involving Analytic Hierarchy Process (AHP) and Data Envelopment Analysis (DEA) to solve facility layout design problems. A case example is considered to demonstrate the results achieved.
Analytical Solutions of Heat-Conduction Problems with Time-Varying Heat-Transfer Coefficients
NASA Astrophysics Data System (ADS)
Kudinov, V. A.; Eremin, A. V.; Stefanyuk, E. V.
2015-05-01
The problem on heat conduction of an infinite plate with a heat-transfer coefficient changing linearly with time for third-kind boundary conditions was solved analytically based on determination of the front of a temperature disturbance in this plate and introduction of additional boundary conditions. On the basis of the solution obtained, graphs of the distribution of isotherms in the indicated plate and the velocities of their movement along a spatial variable in it were constructed. As a result of the solution of the inverse problem on the heat conduction of the infinite plate with the use of the results of numerical calculation of the change in its temperature at any point on the indicated spatial coordinate, the Predvoditelev number was identified with an accuracy of 2%, which made it possible to determine the time dependence of the heat-transfer coefficient of the plate.
A linear analytical boundary element method (BEM) for 2D homogeneous potential problems
NASA Astrophysics Data System (ADS)
Friedrich, Jürgen
2002-06-01
The solution of potential problems is not only fundamental for geosciences, but also an essential part of related subjects like electro- and fluid-mechanics. In all fields, solution algorithms are needed that should be as accurate as possible, robust, simple to program, easy to use, fast and small in computer memory. An ideal technique to fulfill these criteria is the boundary element method (BEM) which applies Green's identities to transform volume integrals into boundary integrals. This work describes a linear analytical BEM for 2D homogeneous potential problems that is more robust and precise than numerical methods because it avoids numerical schemes and coordinate transformations. After deriving the solution algorithm, the introduced approach is tested against different benchmarks. Finally, the gained method was incorporated into an existing software program described before in this journal by the same author.
ERIC Educational Resources Information Center
Yoon, Heojeong; Woo, Ae Ja; Treagust, David; Chandrasegaran, A. L.
2014-01-01
The efficacy of problem-based learning (PBL) in an analytical chemistry laboratory course was studied using a programme that was designed and implemented with 20 students in a treatment group over 10 weeks. Data from 26 students in a traditional analytical chemistry laboratory course were used for comparison. Differences in the creative thinking…
Experimental and analytical comparison of aerodynamic characteristics of a forward-control missile
NASA Technical Reports Server (NTRS)
Blair, A. B.; Rapp, G. H.
1980-01-01
Comparisons of analytical and experimental aerodynamic data for canard controlled missile configurations are presented. Recently, techniques to estimate the longitudinal, directional and lateral aerodynamic characteristics for cruciform missiles have been developed. Nielsen Engineering and Research, Inc. (NEAR, Inc.), supported by various governmental agencies, has been the originator of many of these new computational techniques. Two of these are major computer programs currently being implemented by several research organizations. Predicted data from these two programs are compared with experimental data recently obtained at the NASA Langley Research Center Unitary Plan wind tunnel facility. Comparisons cover the supersonic Mach number regime of 1.60 to 3.50, angles-of-attack from 0 to 20 degrees and roll angles of 0, 26.57 and 45 degrees. Major emphasis is on the roll characteristics due to aileron with limited longitudinal and directional characteristics addressed.
NASA Astrophysics Data System (ADS)
Broman, Karolina; Bernholt, Sascha; Parchmann, Ilka
2015-05-01
found successful to analyse both the test items as well as students' responses in a systematic way. The framework can therefore be applied in the design of new tasks, the analysis and assessment of students' responses, and as a tool for teachers to scaffold students in their problem-solving process. Conclusions:This paper gives implications for practice and for future research to both develop new context-based problems in a structured way, as well as providing analytical tools for investigating students' higher order thinking in their responses to these tasks.
Smith, Douglas R; Moy, Marie A; Dolan, Anthony R; Wood, Troy D
2006-04-01
As miniaturization of electrospray continues to become more prevalent in the mass spectrometry arsenal, numerous types of conductive coatings have been developed with miniaturized electrospray emitters. Different conductive coatings have different properties that may lead to differences in analytical performance. This paper investigates and compares the analytical properties of a series of applied conductive coatings for low-flow electrospray ionization developed in this laboratory vs. commercially-available types. Evaporated graphite is thoroughly compared with commercially available polyaniline (PANI) coated emitters and metal coated emitters. Each set of emitters was investigated to determine various performance characteristics, including susceptibility to electrical discharge in both positive and negative ionization modes, as well as emitter reproducibility and generation of a standard curve to determine each emitter coating's limit of detection and limit of quantitation. Furthermore, evaporated graphite and polyaniline coated fused silica capillaries were investigated to determine which coating is more stable over long-term analyses and during electrical discharge. PMID:16568172
Analytical beam-width characteristics of distorted cat-eye reflected beam
NASA Astrophysics Data System (ADS)
Zhao, Yanzhong; Shan, Congmiao; Zheng, Yonghui; Zhang, Laixian; Sun, Huayan
2015-02-01
The analytical expression of beam-width of distorted cat-eye reflected beam under far-field condition is deduced using the approximate three-dimensional analytical formula for oblique detection laser beam passing through cat-eye optical lens with center shelter, and using the definition of second order moment, Gamma function and integral functions. The laws the variation of divergence angle and astigmatism degree of the reflected light with incident angle, focal shift, aperture size, and center shelter ratio are established by numerical calculation, and physical analysis. The study revealed that the cat-eye reflected beam is like a beam transmitted and collimated by the target optical lens, and has the same characteristics as that of Gaussian beam. A proper choice of positive focal shift would result in a divergence angle smaller than that of no focal shift. The astigmatism is mainly caused by incidence angle.
NASA Technical Reports Server (NTRS)
Fasanella, E. L.; Mcgehee, J. R.; Pappas, M. S.
1977-01-01
An experimental and analytical investigation was conducted to determine which characteristics of a light aircraft landing gear influence gear dynamic behavior significantly. The investigation focused particularly on possible modification for load control. Pseudostatic tests were conducted to determine the gear fore-and-aft spring constant, axial friction as a function of drag load, brake pressure-torque characteristics, and tire force-deflection characteristics. To study dynamic tire response, vertical drops were conducted at impact velocities of 1.2, 1.5, and 1.8 m/s onto a level surface; to determine axial-friction effects, a second series of vertical drops were made at 1.5 m/s onto surfaces inclined 5 deg and 10 deg to the horizontal. An average dynamic axial-friction coefficient of 0.15 was obtained by comparing analytical data with inclined surface drop test data. Dynamic strut bending and associated axial friction were found to be severe for the drop tests on the 10 deg surface.
Analytical solutions to general anti-plane shear problems in finite elasticity
NASA Astrophysics Data System (ADS)
Gao, David Yang
2016-03-01
This paper presents a pure complementary energy variational method for solving a general anti-plane shear problem in finite elasticity. Based on the canonical duality-triality theory developed by the author, the nonlinear/nonconvex partial differential equations for the large deformation problem are converted into an algebraic equation in dual space, which can, in principle, be solved to obtain a complete set of stress solutions. Therefore, a general analytical solution form of the deformation is obtained subjected to a compatibility condition. Applications are illustrated by examples with both convex and nonconvex stored strain energies governed by quadratic-exponential and power-law material models, respectively. Results show that the nonconvex variational problem could have multiple solutions at each material point, the complementary gap function and the triality theory can be used to identify both global and local extremal solutions, while the popular convexity conditions (including rank-one condition) provide mainly local minimal criteria and the Legendre-Hadamard condition (i.e., the so-called strong ellipticity condition) does not guarantee uniqueness of solutions. This paper demonstrates again that the pure complementary energy principle and the triality theory play important roles in finite deformation theory and nonconvex analysis.
On the location selection problem using analytic hierarchy process and multi-choice goal programming
NASA Astrophysics Data System (ADS)
Ho, Hui-Ping; Chang, Ching-Ter; Ku, Cheng-Yuan
2013-01-01
Location selection is a crucial decision in cost/benefit analysis of restaurants, coffee shops and others. However, it is difficult to be solved because there are many conflicting multiple goals in the problem of location selection. In order to solve the problem, this study integrates analytic hierarchy process (AHP) and multi-choice goal programming (MCGP) as a decision aid to obtain an appropriate house from many alternative locations that better suit the preferences of renters under their needs. This study obtains weights from AHP and implements it upon each goal using MCGP for the location selection problem. According to the function of multi-aspiration provided by MCGP, decision makers can set multi-aspiration for each location goal to rank the candidate locations. Compared to the unaided selection processes, the integrated approach of AHP and MCGP is a better scientific and efficient method than traditional methods in finding a suitable location for buying or renting a house for business, especially under multiple qualitative and quantitative criteria within a shorter evaluation time. In addition, a real case is provided to demonstrate the usefulness of the proposed method. The results show that the proposed method is able to provide better quality decision than normal manual methods.
Analytical solutions and numerical modeling for a dam-break problem in inclined channels
NASA Astrophysics Data System (ADS)
Pelinovsky, Efim; Didenkulova, Ira; Didenkulov, Oleg; Rodin, Artem
2016-04-01
Here we obtain different analytical solutions of the shallow-water equations for inviscid nonlinear waves in inclined channels. (i) The first solution describes Riemann wave moving up or down alone the channel slope. It requires the initial fluid flow, which often accompanies waves generated by landslides. This solution is valid for a finite time before the wave breaks. (ii) The second solution generalizes the classical dam-break problem for the case of a dam located in the inclined channel. In this case the cross-section of the channel influences the speed of wave propagation inside the channel, and therefore changes wave dynamics inside the channel compare to the plane beach. (iii) The third solution describes the intermediate stage of the wave front dynamics for a dam of a large height. This solution is derived with the use of generalized Carrier-Greenspan approach developed early by Didenkulova & Pelinovsky (2011) and Rybkin et al (2014). Some of the analytical solutions are tested with the means of numerical modeling. The numerical modeling is carried out using the CLAWPACK software based on nonlinear shallow water equations. Application of the described solutions to possible laboratory experiments is discussed.
NASA Astrophysics Data System (ADS)
Cancilla, Devon A.
2001-12-01
Environmental chemists face difficult challenges related to generating, interpreting, and communicating complex chemical data in a manner understandable by nonchemists. For this reason, it is essential that environmental chemistry students develop the skills necessary not only to collect and interpret complex data sets, but also to communicate their findings in a credible manner in nonscientific forums. Key to this requirement is an understanding of the quality assurance/quality control (QA/QC) elements used to support specific findings. This paper describes the development of a problem-based undergraduate environmental analytical chemistry laboratory and its integration with an undergraduate environmental law course. The course is designed to introduce students to the principles of performance-based analytical methods and the use of environmental indicators to perform environmental assessments. Conducting a series of chemical and toxicological tests, chemistry students perform an environmental assessment on the watershed of the mythical City of Rowan. Law students use these assessments to develop legal arguments under both the Safe Drinking Water Act and the Clean Water Act.
An analytical approach to estimate the number of small scatterers in 2D inverse scattering problems
NASA Astrophysics Data System (ADS)
Fazli, Roohallah; Nakhkash, Mansor
2012-07-01
This paper presents an analytical method to estimate the location and number of actual small targets in 2D inverse scattering problems. This method is motivated from the exact maximum likelihood estimation of signal parameters in white Gaussian noise for the linear data model. In the first stage, the method uses the MUSIC algorithm to acquire all possible target locations and in the next stage, it employs an analytical formula that works as a spatial filter to determine which target locations are associated to the actual ones. The ability of the method is examined for both the Born and multiple scattering cases and for the cases of well-resolved and non-resolved targets. Many numerical simulations using both the coincident and non-coincident arrays demonstrate that the proposed method can detect the number of actual targets even in the case of very noisy data and when the targets are closely located. Using the experimental microwave data sets, we further show that this method is successful in specifying the number of small inclusions.
NASA Technical Reports Server (NTRS)
Romanofsky, Robert R.
1989-01-01
In this report, a thorough analytical procedure is developed for evaluating the frequency-dependent loss characteristics and effective permittivity of microstrip lines. The technique is based on the measured reflection coefficient of microstrip resonator pairs. Experimental data, including quality factor Q, effective relative permittivity, and fringing for 50-omega lines on gallium arsenide (GaAs) from 26.5 to 40.0 GHz are presented. The effects of an imperfect open circuit, coupling losses, and loading of the resonant frequency are considered. A cosine-tapered ridge-guide text fixture is described. It was found to be well suited to the device characterization.
Friedman, Ronald S; Förster, Jens
2005-02-01
In 4 experiments, participants were led to focus on either the prospect of positive outcomes (approach anticipation) or the prospect of negative outcomes (avoidance anticipation) and were subsequently administered behavioral measures of relative hemispheric activation. It was found that approach, relative to avoidance-related anticipatory states, produced greater relative right (diminished relative left) hemispheric activation. Experiment 3 additionally demonstrated that this pattern of activation was reversed when approach and avoidance states were not merely anticipatory but were also emotionally arousing. Finally, Experiment 4 replicated earlier findings demonstrating an influence of approach and avoidance anticipatory states on creativity and analytical problem solving (R. S. Friedman & J. Forster, 2001, 2003) and provided evidence that such effects are mediated by differences in relative hemispheric activation. PMID:15841858
NASA Technical Reports Server (NTRS)
Landrum, E. J.; Miller, D. S.
1980-01-01
Trends toward the automation of the design process for airplanes and missiles accentuate the need for analytic techniques for the prediction of aerodynamic characteristics. A number of computer codes have been developed or are under development which show promise of significantly improving the estimation of aerodynamic characteristics for arbitrarily-shaped bodies at supersonic speeds. The programs considered range in complexity from a simple linearized solution employing slender body theory to an exact finite difference solution of the Euler equations. The results from five computer codes are compared with experimental data to determine the accuracy, range of applicability, ease of use, and computer time and cost of the programs. The results provide a useful guide for selecting the appropriate method for treating bodies at the various levels of an automated design process.
NASA Astrophysics Data System (ADS)
Bayón, L.; Grau, J. M.; Ruiz, M. M.; Suárez, P. M.
2012-12-01
One of the most well-known problems in the field of Microeconomics is the Firm's Cost-Minimization Problem. In this paper we establish the analytical expression for the cost function using the Cobb-Douglas model and considering maximum constraints for the inputs. Moreover we prove that it belongs to the class C1.
NASA Technical Reports Server (NTRS)
Lake, Renee C.; Izadpanah, Amir P.; Baucom, Robert M.
1993-01-01
The results from a study aimed at improving the dynamic and aerodynamic characteristics of composite rotor blades through the use of extension-twist coupling are presented. A set of extension-twist-coupled composite spars was manufactured with four plies of graphite-epoxy cloth prepreg. These spars were noncircular in cross-section design and were therefore subject to warping deformations. Three different cross-sectional geometries were developed: D-shape, square, and flattened ellipse. Three spars of each type were fabricated to assess the degree of repeatability in the manufacturing process of extension-twist-coupled structures. Results from free-free vibration tests of the spars were compared with results from normal modes and frequency analyses of companion shell-finite-element models. Five global modes were identified within the frequency range from 0 to 2000 Hz for each spar. The experimental results for only one D-shape spar could be determined, however, and agreed within 13.8 percent of the analytical results. Frequencies corresponding to the five global modes for the three square spars agreed within 9.5, 11.6, and 8.5 percent of the respective analytical results and for the three elliptical spars agreed within 4.9, 7.7, and 9.6 percent of the respective analytical results.
Analytical Characteristics of a Noninvasive Gene Expression Assay for Pigmented Skin Lesions.
Yao, Zuxu; Allen, Talisha; Oakley, Margaret; Samons, Carol; Garrison, Darryl; Jansen, Burkhard
2016-08-01
We previously reported clinical performance of a novel noninvasive and quantitative PCR (qPCR)-based molecular diagnostic assay (the pigmented lesion assay; PLA) that differentiates primary cutaneous melanoma from benign pigmented skin lesions through two target gene signatures, LINC00518 (LINC) and preferentially expressed antigen in melanoma (PRAME). This study focuses on analytical characterization of this PLA, including qPCR specificity and sensitivity, optimization of RNA input in qPCR to achieve a desired diagnostic sensitivity and specificity, and analytical performance (repeatability and reproducibility) of this two-gene PLA. All target qPCRs demonstrated a good specificity (100%) and sensitivity (with a limit of detection of 1-2 copies), which allows reliable detection of gene expression changes of LINC and PRAME between melanomas and nonmelanomas. Through normalizing RNA input in qPCR, we converted the traditional gene expression analyses to a binomial detection of gene transcripts (i.e., detected or not detected). By combining the binomial qPCR results of the two genes, an improved diagnostic sensitivity (raised from 52%- 65% to 71% at 1 pg of total RNA input, and to 91% at 3 pg of total RNA input) was achieved. This two-gene PLA demonstrates a high repeatability and reproducibility (coefficient of variation <3%) and all required analytical performance characteristics for the commercial processing of clinical samples. PMID:27505074
Lethal head entrapment--a problem characteristic of early childhood.
Byard, Roger W; Charlwood, Cheryl
2009-08-01
Accidental deaths in infancy and early childhood often result from young childrens' lack of understanding of the dangers of certain situations and their physical inability to extricate themselves from potentially lethal circumstances. Two cases are reported to demonstrate an age-related susceptibility in the young to lethal head entrapment. Case 1: a 5-month-old girl smothered when she slipped down in her stroller, trapping her head beneath the frame and forcing her face into the soft material of the base. Case 2: a 14-month-old boy was hanged while exploring a filing cabinet when his head became caught between two lower drawers. Additional mental and physical characteristics that predispose young children and infants to lethal head entrapment include an inability to effectively problem solve once confronted with a hazardous situation, and relatively large heads and weak neck musculature. Because of these features lethal head entrapment represents a particular circumstance that may predispose to accidental asphyxial deaths in the very young. A combination of careful death scene and autopsy evaluations will be required to confirm the alleged circumstances of death in these cases, including mortuary re-enactments and assessment of the deceased infant's level of physical maturity and mobility. PMID:19573845
NASA Astrophysics Data System (ADS)
Dalla Riva, M.; Musolino, P.
2014-01-01
We consider a periodically perforated domain obtained by making in R^n a periodic set of holes, each of them of size proportional to \\epsilon. Then we introduce a nonlinear boundary value problem for the Lam\\'e equations in such a periodically perforated domain. The unknown of the problem is a vector valued function u which represents the displacement attained in the equilibrium configuration by the points of a periodic linearly elastic matrix with a hole of size \\epsilon contained in each periodic cell. We assume that the traction exerted by the matrix on the boundary of each hole depends (nonlinearly) on the displacement attained by the points of the boundary of the hole. Then our aim is to describe what happens to the displacement vector function u when \\epsilon tends to 0. Under suitable assumptions we prove the existence of a family of solutions {u(\\epsilon,.) : \\epsilon \\in ]0,\\epsilon'[} with a prescribed limiting behaviour when \\epsilon approaches 0. Moreover, the family {u(\\epsilon,.) : \\epsilon \\in ]0,\\epsilon'[} is in a sense locally unique and can be continued real analytically for negative values of \\epsilon.
NASA Technical Reports Server (NTRS)
Lara, Martin; Palacian, Jesus F.
2007-01-01
Frozen orbits of the Hill problem are determined in the double averaged problem, where short and long period terms are removed by means of Lie transforms. The computation of initial conditions of corresponding quasi periodic solutions in the non-averaged problem is straightforward for the perturbation method used provides the explicit equations of the transformation that connects the averaged and non-averaged models. A fourth order analytical theory reveals necessary for the accurate computation of quasi periodic, frozen orbits.
Hard Data Analytics Problems Make for Better Data Analysis Algorithms: Bioinformatics as an Example
Widera, Paweł; Lazzarini, Nicola; Krasnogor, Natalio
2014-01-01
Abstract Data mining and knowledge discovery techniques have greatly progressed in the last decade. They are now able to handle larger and larger datasets, process heterogeneous information, integrate complex metadata, and extract and visualize new knowledge. Often these advances were driven by new challenges arising from real-world domains, with biology and biotechnology a prime source of diverse and hard (e.g., high volume, high throughput, high variety, and high noise) data analytics problems. The aim of this article is to show the broad spectrum of data mining tasks and challenges present in biological data, and how these challenges have driven us over the years to design new data mining and knowledge discovery procedures for biodata. This is illustrated with the help of two kinds of case studies. The first kind is focused on the field of protein structure prediction, where we have contributed in several areas: by designing, through regression, functions that can distinguish between good and bad models of a protein's predicted structure; by creating new measures to characterize aspects of a protein's structure associated with individual positions in a protein's sequence, measures containing information that might be useful for protein structure prediction; and by creating accurate estimators of these structural aspects. The second kind of case study is focused on omics data analytics, a class of biological data characterized for having extremely high dimensionalities. Our methods were able not only to generate very accurate classification models, but also to discover new biological knowledge that was later ratified by experimentalists. Finally, we describe several strategies to tightly integrate knowledge extraction and data mining in order to create a new class of biodata mining algorithms that can natively embrace the complexity of biological data, efficiently generate accurate information in the form of classification/regression models, and extract valuable
NASA Astrophysics Data System (ADS)
de Saedeleer, Bernard
2005-03-01
This paper is a contribution to the Theory of the Artificial Satellite, within the frame of the Lie Transform as canonical perturbation technique (elimination of the short period terms). We consider the perturbation by any zonal harmonic J n (n ≥ 2) of the primary on the satellite, what we call here the complete zonal problem of the artificial satellite. This is quite useful for primaries with symmetry of revolution. We give an analytical formula to compute directly the first order averaged Hamiltonian. The computation is carried out in closed form for all terms, avoiding therefore tedious expansions in the eccentricity or in any anomaly; this feature makes the averaging process, not only valid for all kind of elliptic trajectories but at the same time it yields the averaged Hamiltonian in a very short and compact way. The formula allows us to now skip the averaging process, which means an asymptotic gain of a factor 3n/2 regarding the computational cost of the n th zonal. Our analytical formulae have been widely checked, by comparison on one hand with published works (Brouwer, 1959) (which contained results for particular zonal harmonics, let’s say typically from J 2 to J 8), and on the other hand with the results of 3 symbolic manipulation software, among which the MM (standing for ‘Moon’s series Manipulator’), which has already been used and described in (De Saedeleer B., 2004). Additionally, the first order generator associated with this transformation is given into the same closed form, and has also been validated.
Critical Task Characteristics in Problem-Based Learning
ERIC Educational Resources Information Center
Otting, Hans; Zwaal, Wichard
2006-01-01
Tasks and problems in problem-based learning (PBL) are supposed to trigger and structure the learning process. The quality of problems in PBL is generally regarded as an important driver of the individual and collaborative learning processes. Although the importance of the PBL task is widely recognized, there is a lack of empirical findings and…
NASA Astrophysics Data System (ADS)
Yang, D. G.; Choi, Y. H.; Kim, Y. G.; Song, J. B.; Lee, H. G.
2016-03-01
This paper presents results, experimental and analytical, of the electrical characteristics of GdBCO single-pancake coils co-wound with a brass tape as metallic insulation (MI coil). The GdBCO pancakes were subjected to sudden discharge, charge-discharge, and over-current tests. The sudden discharge and charge-discharge test results of the MI coil demonstrated that MI coils can be charged and discharged significantly faster than non-insulated coils that are wound only with GdBCO tape. In over-current tests at 150 A (1.25Ic), the MI coil exhibited better electrical behavior, i.e., self-protecting features, than its counterpart co-wound with Kapton tape, an insulator. Moreover, the experimental and analytical results are in agreement, validating the use of a concise equivalent parallel-RL circuit model for the MI coil to characterize its electrical behavior. Overall, the MI winding technique is highly promising to help build compact, mechanically robust, and self-protecting magnets composed of REBCO pancake coils. With no organic material in the winding, MI REBCO pancakes will be immune to neutron radiation damage, making the MI winding technique a viable option for fusion reactors, such as for toroidal field, poroidal field magnets, and central solenoid.
Yang, D G; Choi, Y H; Kim, Y G; Song, J B; Lee, H G
2016-03-01
This paper presents results, experimental and analytical, of the electrical characteristics of GdBCO single-pancake coils co-wound with a brass tape as metallic insulation (MI coil). The GdBCO pancakes were subjected to sudden discharge, charge-discharge, and over-current tests. The sudden discharge and charge-discharge test results of the MI coil demonstrated that MI coils can be charged and discharged significantly faster than non-insulated coils that are wound only with GdBCO tape. In over-current tests at 150 A (1.25I(c)), the MI coil exhibited better electrical behavior, i.e., self-protecting features, than its counterpart co-wound with Kapton tape, an insulator. Moreover, the experimental and analytical results are in agreement, validating the use of a concise equivalent parallel-RL circuit model for the MI coil to characterize its electrical behavior. Overall, the MI winding technique is highly promising to help build compact, mechanically robust, and self-protecting magnets composed of REBCO pancake coils. With no organic material in the winding, MI REBCO pancakes will be immune to neutron radiation damage, making the MI winding technique a viable option for fusion reactors, such as for toroidal field, poroidal field magnets, and central solenoid. PMID:27036797
Applied Analytical Methods for Solving Some Problems of Wave Propagation in the Coastal Areas
NASA Astrophysics Data System (ADS)
Gagoshidze, Shalva; Kodua, Manoni
2016-04-01
Analytical methods, easy for application, are proposed for the solution of the following four classical problems of coastline hydro mechanics: 1. Refraction of waves on coast slopes of arbitrary steepness; 2. Wave propagation in tapering water areas; 3. Longitudinal waves in open channels; 4. Long waves on uniform and non-uniform flows of water. The first three of these problems are solved by the direct Galerkin-Kantorovich method with a choice , of basic functions which completely satisfy all boundary conditions. This approach leads to obtaining new evolutionary equations which can be asymptotically solved by the WKB method. The WKB solution of the first problem enables us to easily determine the three-dimensional field of velocities and to construct the refraction picture of the wave surface near the coast having an arbitrary angle of slope to the horizon varying from 0° to 180°. This solution, in particular for a vertical cliff, fully agrees with Stoker's particular but difficult solution. Moreover, it is shown for the first time that our Schrödinger type evolutionary equation leads to the formation of the so-called "potential wells" if the angle of coast slope to the horizon exceeds 45°, while the angle given at infinity (i.e. at a large distance from the shore) between the wave crests and the coastline exceeds 75°. This theoretical result expressed in terms of elementary functions is well consistent with the experimental observations and with lot of aerial photographs of waves in the coastal zones of the oceans [1,2]. For the second problem we introduce the notions of "wide" and "narrow" water areas. It is shown that Green's law on the wave height growth holds only for the narrow part of the water area, whereas in the wide part the tapering of the water area leads to an insignificant decrease of the wave height. For the third problem, the bank slopes of trapezoidal channels are assumed to have an arbitrary angle of steepness. So far we have known the
ERIC Educational Resources Information Center
Thorsland, Martin N.; Novak, Joseph D.
1974-01-01
Described is an approach to assessment of intuitive and analytic modes of thinking in physics. These modes of thinking are associated with Ausubel's theory of learning. High ability in either intuitive or analytic thinking was associated with success in college physics, with high learning efficiency following a pattern expected on the basis of…
NASA Astrophysics Data System (ADS)
Moench, Allen F.
2008-06-01
A 7-d, constant rate aquifer test conducted by University of Waterloo researchers at Canadian Forces Base Borden in Ontario, Canada, is useful for advancing understanding of fluid flow processes in response to pumping from an unconfined aquifer. Measured data include not only drawdown in the saturated zone but also volumetric soil moisture measured at various times and distances from the pumped well. Analytical analyses were conducted with the model published in 2001 by Moench and colleagues, which allows for gradual drainage but does not include unsaturated zone characteristics, and the model published in 2006 by Mathias and Butler, which assumes that moisture retention and relative hydraulic conductivity (RHC) in the unsaturated zone are exponential functions of pressure head. Parameters estimated with either model yield good matches between measured and simulated drawdowns in piezometers. Numerical analyses were conducted with two versions of VS2DT: one that uses traditional Brooks and Corey functional relations and one that uses a RHC function introduced in 2001 by Assouline that includes an additional parameter that accounts for soil structure and texture. The analytical model of Mathias and Butler and numerical model of VS2DT with the Assouline model both show that the RHC function must contain a fitting parameter that is different from that used in the moisture retention function. Results show the influence of field-scale heterogeneity and suggest that the RHC at the Borden site declines more rapidly with elevation above the top of the capillary fringe than would be expected if the parameters were to reflect local- or core-scale soil structure and texture.
Moench, A.F.
2008-01-01
A 7-d, constant rate aquifer test conducted by University of Waterloo researchers at Canadian Forces Base Borden in Ontario, Canada, is useful for advancing understanding of fluid flow processes in response to pumping from an unconfined aquifer. Measured data include not only drawdown in the saturated zone but also volumetric soil moisture measured at various times and distances from the pumped well. Analytical analyses were conducted with the model published in 2001 by Moench and colleagues, which allows for gradual drainage but does not include unsaturated zone characteristics, and the model published in 2006 by Mathias and Butler, which assumes that moisture retention and relative hydraulic conductivity (RHC) in the unsaturated zone are exponential functions of pressure head. Parameters estimated with either model yield good matches between measured and simulated drawdowns in piezometers. Numerical analyses were conducted with two versions of VS2DT: one that uses traditional Brooks and Corey functional relations and one that uses a RHC function introduced in 2001 by Assouline that includes an additional parameter that accounts for soil structure and texture. The analytical model of Mathias and Butler and numerical model of VS2DT with the Assouline model both show that the RHC function must contain a fitting parameter that is different from that used in the moisture retention function. Results show the influence of field-scale heterogeneity and suggest that the RHC at the Borden site declines more rapidly with elevation above the top of the capillary fringe than would be expected if the parameters were to reflect local- or core-scale soil structure and texture.
A measurement-based analytical approach to the bioluminescence tomography problem
NASA Astrophysics Data System (ADS)
Erkol, Hakan; Demirkiran, Aytac; Kipergil, Esra-Aytac; Uluc, Nasire; Unlu, Mehmet B.
2014-03-01
This work presents an analytical approach for the solution of the tissue diffusion equation based on the bound- ary measurements. We consider a bioluminescent point source in both homogeneous and heterogeneous circular turbid media. The point source is described by the Dirac delta function. Analytical expressions for the strength and position of the point source are obtained introducing boundary measurements and then applying appropriate boundary conditions. In addition, numerical simulations are performed for the position of the source. Calculations show that that the analytical results are in a good accordance with the numerical results.
Arnab, Salman M.; Kabir, M. Z.
2014-01-21
An analytical model for analyzing the current-voltage (J-V) characteristics of bulk heterojunction (BHJ) organic solar cells is developed by incorporating exponential photon absorption, dissociation efficiency of bound electron-hole pairs (EHPs), carrier trapping, and carrier drift and diffusion in the photon absorption layer. Modified Braun's model is used to compute the electric field-dependent dissociation efficiency of the bound EHPs. The charge carrier concentrations and hence the photocurrent are calculated by solving the carrier continuity equation for both holes and electrons in the organic layer. The overall load current is calculated considering the actual solar spectrum and voltage dependent forward dark current. The model is verified by published experimental results. The efficiency of the P3HT:PCBM based solar cells critically depends on the dissociation of bound EHPs. On the other hand, cells made of a blend of the conjugated polymer (PCDTBT) with the soluble fullerene derivative (PCBM) show nearly unity dissociation efficiency, and their cell efficiency strongly depends on the charge collection efficiency. The effects of carrier lifetimes on the performance of PCDTBT solar cells have also been studied. The model is also used to investigate the effect of titanium oxide (TiO{sub x}) layer (at the back contact) on the J-V characteristics of PCDTBT solar cells. The results of this paper indicate that improvement of charge carrier transport in PCDTBT:PCBM blend and dissociation of bound EHPs in P3HT:PCBM blend are extremely important to increase the power conversion efficiency of the respective BHJ solar cells.
NASA Astrophysics Data System (ADS)
Arnab, Salman M.; Kabir, M. Z.
2014-01-01
An analytical model for analyzing the current-voltage (J-V) characteristics of bulk heterojunction (BHJ) organic solar cells is developed by incorporating exponential photon absorption, dissociation efficiency of bound electron-hole pairs (EHPs), carrier trapping, and carrier drift and diffusion in the photon absorption layer. Modified Braun's model is used to compute the electric field-dependent dissociation efficiency of the bound EHPs. The charge carrier concentrations and hence the photocurrent are calculated by solving the carrier continuity equation for both holes and electrons in the organic layer. The overall load current is calculated considering the actual solar spectrum and voltage dependent forward dark current. The model is verified by published experimental results. The efficiency of the P3HT:PCBM based solar cells critically depends on the dissociation of bound EHPs. On the other hand, cells made of a blend of the conjugated polymer (PCDTBT) with the soluble fullerene derivative (PCBM) show nearly unity dissociation efficiency, and their cell efficiency strongly depends on the charge collection efficiency. The effects of carrier lifetimes on the performance of PCDTBT solar cells have also been studied. The model is also used to investigate the effect of titanium oxide (TiOx) layer (at the back contact) on the J-V characteristics of PCDTBT solar cells. The results of this paper indicate that improvement of charge carrier transport in PCDTBT:PCBM blend and dissociation of bound EHPs in P3HT:PCBM blend are extremely important to increase the power conversion efficiency of the respective BHJ solar cells.
O'Rourke, Joanne McFarland; Roehrig, Stephen; Heeringa, Steven G; Reed, Beth Glover; Birdsall, William C; Overcashier, Margaret; Zidar, Kelly
2006-09-01
MEASURES USED TO PROTECT SUBJECTS in publicly distributed microdata files often have a significant negative impact on key analytic uses of the data. For example, it may be important to analyze subpopulations within a data file such as racial minorities, yet these subjects may present the greatest disclosure risk because their records tend to stand out or be unique. Files or records that are linkable create another type of disclosure risk-common elements between two files can be used to link files with sensitive data to externally available files that disclose identity. Examples of disclosure limitation methods used to address these types of issues include blanking out data, coarsening response categories, or withholding data altogether. However, the very detail that creates the greatest risk also provides insight into differences that are of greatest interest to analysts. Restricted-use agreements that provide unaltered versions of the data may not be available, or only selectively so. The public-use version of the data is very important because it is likely to be the only one to which most researchers, policy analysts, teaching faculty, and students will ever have access. Hence, it is the version from which much of the utility of the data is extracted and often it effectively becomes the historical record of the data collection. This underscores the importance that the disclosure review c ommittee s trikes a g ood b alance b etween protection and u tility. In this paper we d escrib e our disclosure review committee's (DRC) analysis and resulting data protection plans for two national studies and one administrative data system. Three distinct disclosure limitation methods were employed, taking key uses of the data into consideration, to protect respondents while still providing statistically accurate and highly useful public-use data. The techniques include data swapping, microaggregation, and suppression of detailed geographic data. We describe the characteristics
Analytic Solution to the Problem of Aircraft Electric Field Mill Calibration
NASA Technical Reports Server (NTRS)
Koshak, William
2003-01-01
It is by no means a simple task to retrieve storm electric fields from an aircraft instrumented with electric field mill sensors. The presence of the aircraft distorts the ambient field in a complicated way. Before retrievals of the storm field can be made, the field mill measurement system must be "calibrated". In other words, a relationship between impressed (i.e., ambient) electric field and mill output must be established. If this relationship can be determined, it is mathematically inverted so that ambient field can be inferred from the mill outputs. Previous studies have primarily focused on linear theories where the relationship between ambient field and mill output is described by a "calibration matrix" M. Each element of the matrix describes how a particular component of the ambient field is enhanced by the aircraft. For example the product M(sub ix), E(sub x), is the contribution of the E(sub x) field to the i(th) mill output. Similarly, net aircraft charge (described by a "charge field component" E(sub q)) contributes an amount M(sub iq)E(sub q) to the output of the i(th) sensor. The central difficulty in obtaining M stems from the fact that the impressed field (E(sub x), E(sub y), E(sub z), E(sub q) is not known but is instead estimated. Typically, the aircraft is flown through a series of roll and pitch maneuvers in fair weather, and the values of the fair weather field and aircraft charge are estimated at each point along the aircraft trajectory. These initial estimates are often highly inadequate, but several investigators have improved the estimates by implementing various (ad hoc) iterative methods. Unfortunately, none of the iterative methods guarantee absolute convergence to correct values (i.e., absolute convergence to correct values has not been rigorously proven). In this work, the mathematical problem is solved directly by analytic means. For m mills installed on an arbitrary aircraft, it is shown that it is possible to solve for a single 2m
Some Problems of Rocket-Space Vehicles' Characteristics co- ordination
NASA Astrophysics Data System (ADS)
Sergienko, Alexander A.
2002-01-01
of the XX century suffered a reverse. The designers of the United States' firms and enterprises of aviation and rocket-space industry (Boeing, Rocketdyne, Lockheed Martin, McDonnell Douglas, Rockwell, etc.) and NASA (Marshall Space Flight Center, Johnson Space Center, Langley Research Center and Lewis Research Center and others) could not correctly co-ordinate the characteristics of a propulsion system and a space vehicle for elaboration of the "Single-Stage-To-Orbit" reusable vehicle (SSTO) as an integral whole system, which is would able to inject a payload into an orbit and to return back on the Earth. jet nozzle design as well as the choice of propulsion system characteristics, ensuring the high ballistic efficiency, are considered in the present report. The efficiency criterions for the engine and launch system parameters optimization are discussed. The new methods of the nozzle block optimal parameters' choice for the satisfaction of the object task of flight are suggested. The family of SSTO with a payload mass from 5 to 20 ton and initial weight under 800 ton is considered.
Problems with the differential receiver operating characteristic (DROC) method
NASA Astrophysics Data System (ADS)
Chakraborty, Dev P.
2004-05-01
Most papers in these proceedings present ideas that work. This is the story of an idea that did not work as intended. The differential receiver operating characteristic (DROC) method was proposed about 8 years ago. It was intended to measure the difference in performance between two imaging modalities. It was expected that the DROC method could outperform the ROC method in statistical power. This expectation has not been borne out and the author no longer recommends the DROC method. The purpose of this paper is to present a critical look at this method, why the author initially believed it should work, the assumptions involved and the fallacies. The author believes there is value to this frank account as it has yielded, at least for the author, new insights into ROC analysis. The author concludes with a few personal reflections on his experience with this project and advice on how to deal with negative results.
NASA Technical Reports Server (NTRS)
Gossard, Myron L
1952-01-01
An iterative transformation procedure suggested by H. Wielandt for numerical solution of flutter and similar characteristic-value problems is presented. Application of this procedure to ordinary natural-vibration problems and to flutter problems is shown by numerical examples. Comparisons of computed results with experimental values and with results obtained by other methods of analysis are made.
Filho, J. F. P.
2013-07-01
In this work, an analytical discrete ordinates method is used to solve a nodal formulation of a neutron transport problem in x, y-geometry. The proposed approach leads to an important reduction in the order of the associated eigenvalue systems, when combined with the classical level symmetric quadrature scheme. Auxiliary equations are proposed, as usually required for nodal methods, to express the unknown fluxes at the boundary introduced as additional unknowns in the integrated equations. Numerical results, for the problem defined by a two-dimensional region with a spatially constant and isotropically emitting source, are presented and compared with those available in the literature. (authors)
How Big of a Problem is Analytic Error in Secondary Analyses of Survey Data?
West, Brady T.; Sakshaug, Joseph W.; Aurelien, Guy Alain S.
2016-01-01
Secondary analyses of survey data collected from large probability samples of persons or establishments further scientific progress in many fields. The complex design features of these samples improve data collection efficiency, but also require analysts to account for these features when conducting analysis. Unfortunately, many secondary analysts from fields outside of statistics, biostatistics, and survey methodology do not have adequate training in this area, and as a result may apply incorrect statistical methods when analyzing these survey data sets. This in turn could lead to the publication of incorrect inferences based on the survey data that effectively negate the resources dedicated to these surveys. In this article, we build on the results of a preliminary meta-analysis of 100 peer-reviewed journal articles presenting analyses of data from a variety of national health surveys, which suggested that analytic errors may be extremely prevalent in these types of investigations. We first perform a meta-analysis of a stratified random sample of 145 additional research products analyzing survey data from the Scientists and Engineers Statistical Data System (SESTAT), which describes features of the U.S. Science and Engineering workforce, and examine trends in the prevalence of analytic error across the decades used to stratify the sample. We once again find that analytic errors appear to be quite prevalent in these studies. Next, we present several example analyses of real SESTAT data, and demonstrate that a failure to perform these analyses correctly can result in substantially biased estimates with standard errors that do not adequately reflect complex sample design features. Collectively, the results of this investigation suggest that reviewers of this type of research need to pay much closer attention to the analytic methods employed by researchers attempting to publish or present secondary analyses of survey data. PMID:27355817
ERIC Educational Resources Information Center
Thorsland, Martin N.; Novak, Joseph D.
A study on individual differences in problem solving approach and their relationships to various learning-related parameters was conducted with a random sample of 25 subjects enrolled in an introductory physics course utilizing instruction through audio-tutorial methods. The subjects received interviews consisting of four problems in energy…
Analytical Problems and Suggestions in the Analysis of Behavioral Economic Demand Curves.
Yu, Jihnhee; Liu, Liu; Collins, R Lorraine; Vincent, Paula C; Epstein, Leonard H
2014-01-01
Behavioral economic demand curves (Hursh, Raslear, Shurtleff, Bauman, & Simmons, 1988) are innovative approaches to characterize the relationships between consumption of a substance and its price. In this article, we investigate common analytical issues in the use of behavioral economic demand curves, which can cause inconsistent interpretations of demand curves, and then we provide methodological suggestions to address those analytical issues. We first demonstrate that log transformation with different added values for handling zeros changes model parameter estimates dramatically. Second, demand curves are often analyzed using an overparameterized model that results in an inefficient use of the available data and a lack of assessment of the variability among individuals. To address these issues, we apply a nonlinear mixed effects model based on multivariate error structures that has not been used previously to analyze behavioral economic demand curves in the literature. We also propose analytical formulas for the relevant standard errors of derived values such as P max, O max, and elasticity. The proposed model stabilizes the derived values regardless of using different added increments and provides substantially smaller standard errors. We illustrate the data analysis procedure using data from a relative reinforcement efficacy study of simulated marijuana purchasing. PMID:26741176
Zatsiorsky, Vladimir M.
2011-01-01
One of the key problems of motor control is the redundancy problem, in particular how the central nervous system (CNS) chooses an action out of infinitely many possible. A promising way to address this question is to assume that the choice is made based on optimization of a certain cost function. A number of cost functions have been proposed in the literature to explain performance in different motor tasks: from force sharing in grasping to path planning in walking. However, the problem of uniqueness of the cost function(s) was not addressed until recently. In this article, we analyze two methods of finding additive cost functions in inverse optimization problems with linear constraints, so-called linear-additive inverse optimization problems. These methods are based on the Uniqueness Theorem for inverse optimization problems that we proved recently (Terekhov et al., J Math Biol 61(3):423–453, 2010). Using synthetic data, we show that both methods allow for determining the cost function. We analyze the influence of noise on the both methods. Finally, we show how a violation of the conditions of the Uniqueness Theorem may lead to incorrect solutions of the inverse optimization problem. PMID:21311907
Terekhov, Alexander V; Zatsiorsky, Vladimir M
2011-02-01
One of the key problems of motor control is the redundancy problem, in particular how the central nervous system (CNS) chooses an action out of infinitely many possible. A promising way to address this question is to assume that the choice is made based on optimization of a certain cost function. A number of cost functions have been proposed in the literature to explain performance in different motor tasks: from force sharing in grasping to path planning in walking. However, the problem of uniqueness of the cost function(s) was not addressed until recently. In this article, we analyze two methods of finding additive cost functions in inverse optimization problems with linear constraints, so-called linear-additive inverse optimization problems. These methods are based on the Uniqueness Theorem for inverse optimization problems that we proved recently (Terekhov et al., J Math Biol 61(3):423-453, 2010). Using synthetic data, we show that both methods allow for determining the cost function. We analyze the influence of noise on the both methods. Finally, we show how a violation of the conditions of the Uniqueness Theorem may lead to incorrect solutions of the inverse optimization problem. PMID:21311907
A meta-analytic study of self-help interventions for anxiety problems.
Hirai, Michiyo; Clum, George A
2006-06-01
The present study examined the effectiveness of self-help (SH) interventions for individuals with anxiety problems. Thirty-three studies, targeting a variety of anxiety disorders and problems, met criteria for inclusion with 1,582 clinical and subclinical participants. Self-help formats included books, audio/videotapes, and computer/Internet-based programs. The average effect sizes (Cohen's ds) comparing SH interventions to control groups for target symptoms were .62 at posttreatment and .51 at follow-up. When compared to therapist-directed interventions (TDIs), the average effect sizes (Cohen's ds) for target problems were -.42 at posttreatment and -.36 at follow-up. Format of SH materials, type of target disorder, presence of minimal therapist contact, and other study parameters were examined for their effect on treatment outcome. The results were discussed from the perspective of a stepped-care approach for anxiety problems. PMID:16942965
A noncanonical analytic solution to the J2 perturbed two-body problem
NASA Technical Reports Server (NTRS)
Jezewski, D. J.
1983-01-01
The motion of a satellite subject to an inverse-square gravitational force of attraction and a perturbation due to the earth's oblateness as the J2 term is analyzed, and a uniform, analytic solution correct to first-order in J2, is obtained using a noncanonical approach. The basis for the solution is the transformation and uncoupling of the differential equations for the model. The resulting solution is expressed in terms of elementary functions of the independent variable (the 'true anomaly'), and is of a compact and simple form. Numerical results are comparable to existing solutions.
Gray, D.B.; McMechan, G.A.
1995-06-01
The analytic solution of the Lippman-Schwinger seismic inverse problem in three spatial dimensions, assuming a point source and a constant-density earth model, is valid in the spatial zero frequency limit. It is expressed as a two-dimensional inverse Fourier transform followed by an inverse Laplace transform. For the case of laterally homogeneous velocity, the analytic solution is correct when applied to a forward solution of the wave equation for a single-interface velocity model. Error surfaces of the non-linear, iterative, least-squares inversions corresponding to multiple, constant-velocity, horizontal layers have an absolute minimum at or near the location of the solution parameters for zero and low frequencies. The error surface for a scattered wavefield dataset generated by 3D finite-difference modeling combined with a priori constraints, produces nearly correct solutions for a range of low frequencies. Thus, this approach has potential for applicability to field data. 24 refs., 7 figs.
Zimmerman, R.W.; Bodvarsson, G.S.
1990-01-01
Various analytical and numerical approaches are presented for the study of unsaturated flow processes in the vicinity of the Yucca Mountain, Nevada, the proposed site of an underground radioactive waste repository. Approximate analytical methods are used to study absorption of water from a saturated fracture into the adjacent rock. These solutions are incorporated into a numerical simulator as fracture/matrix interaction terms to treat problems such as flow along a fracture with transverse leakage into the matrix. An automatic fracture/matrix mesh generator is described; it allows for more efficient mesh generation for fractured/porous media, and consequently leads to large savings in computational time and cost. 21 refs., 6 figs.
An analytical solution for the magneto-electro-elastic bimorph beam forced vibrations problem
NASA Astrophysics Data System (ADS)
Milazzo, A.; Orlando, C.; Alaimo, A.
2009-08-01
Based on the Timoshenko beam theory and on the assumption that the electric and magnetic fields can be treated as steady, since elastic waves propagate very slowly with respect to electromagnetic ones, a general analytical solution for the transient analysis of a magneto-electro-elastic bimorph beam is obtained. General magneto-electric boundary conditions can be applied on the top and bottom surfaces of the beam, allowing us to study the response of the bilayer structure to electromagnetic stimuli. The model reveals that the magneto-electric loads enter the solution as an equivalent external bending moment per unit length and as time-dependent mechanical boundary conditions through the definition of the bending moment. Moreover, the influences of the electro-mechanic, magneto-mechanic and electromagnetic coupling on the stiffness of the bimorph stem from the computation of the beam equivalent stiffness constants. Free and forced vibration analyses of both multiphase and laminated magneto-electro-elastic composite beams are carried out to check the effectiveness and reliability of the proposed analytic solution.
Analytic Challenges Arising from the STOP CRC Trial: Pragmatic Solutions for Pragmatic Problems
Vollmer, William M.; Green, Beverly B.; Coronado, Gloria D.
2015-01-01
Context: Pragmatic trials lack the relatively tight quality control of traditional efficacy studies and hence may pose added analytic challenges owing to the practical realities faced in carrying them out. Case Description: STOP CRC is a cluster randomized trial testing the effectiveness of automated, electronic medical record (EMR)-driven strategies to raise colorectal cancer (CRC) screening rates in safety net clinics. Screen-eligible participants were accrued during year 1 and followed for 12 months (measurement window) to assess completion of a fecal screening test. Control clinics implemented the intervention in year 2. Implementation Challenges/Analytic Issues: Due to limitations on how we could build the intervention tools, the overlap of the year 1 measurement windows with year 2 intervention rollout posed a potential for contamination of the primary outcome for control participants. In addition, a variety of factors led to a lack of synchronization of the measurement windows with actual intervention delivery. In both cases, the net impact of these factors would be to diminish the estimated impact of the intervention. Proposed Solutions: We dealt with the overlap issue by delaying the start of intervention rollout to control clinics in year 2 by 6 months and by truncating the measurement windows for intervention and control participants at this point. In addition we formulated three sensitivity analyses to help address the issue of asynchronization. Conclusion: This case study might help other investigators facing similar challenges think about such issues and the pros and cons of various strategies for dealing with them. PMID:26793738
Fast Single Image Super-Resolution Using a New Analytical Solution for l2 - l2 Problems.
Zhao, Ningning; Wei, Qi; Basarab, Adrian; Dobigeon, Nicolas; Kouame, Denis; Tourneret, Jean-Yves
2016-08-01
This paper addresses the problem of single image super-resolution (SR), which consists of recovering a high-resolution image from its blurred, decimated, and noisy version. The existing algorithms for single image SR use different strategies to handle the decimation and blurring operators. In addition to the traditional first-order gradient methods, recent techniques investigate splitting-based methods dividing the SR problem into up-sampling and deconvolution steps that can be easily solved. Instead of following this splitting strategy, we propose to deal with the decimation and blurring operators simultaneously by taking advantage of their particular properties in the frequency domain, leading to a new fast SR approach. Specifically, an analytical solution is derived and implemented efficiently for the Gaussian prior or any other regularization that can be formulated into an l2 -regularized quadratic model, i.e., an l2 - l2 optimization problem. The flexibility of the proposed SR scheme is shown through the use of various priors/regularizations, ranging from generic image priors to learning-based approaches. In the case of non-Gaussian priors, we show how the analytical solution derived from the Gaussian case can be embedded into traditional splitting frameworks, allowing the computation cost of existing algorithms to be decreased significantly. Simulation results conducted on several images with different priors illustrate the effectiveness of our fast SR approach compared with existing techniques. PMID:27187960
NASA Astrophysics Data System (ADS)
Zhao, Y. H.; Li, W. M.; Chin, J. S.
1986-06-01
The variation of spray characteristics (Sauter Mean Diameter and Rosin-Rammler drop-size distribution parameter) downstream of a pressure swirl atomizer along radial distance has been measured by laser light scattering technology. An analytical model has been developed that is capable of predicting the variation of spray characteristics along radial distance. A comparison between the prediction and experimental data shows excellent agreement. It shows that the spray model proposed, although relatively simple, is correct and can be used with some expansion and modification to predict more complicated spray systems.
Peer and Parenting Characteristics of Boys and Girls with Subclinical Attention Problems
ERIC Educational Resources Information Center
Rielly, Nicole E.; Craig, Wendy M.; Parker, Kevin C. H.
2006-01-01
Objective: This study examines peer and parenting characteristics of 149 boys and girls with and without subclinical attention problems. Method: Multivariate analyses showed that children with attention problems had higher levels of negative peer nominations and conflict and betrayal in friendships, and their parents tended to use higher levels of…
NASA Technical Reports Server (NTRS)
Carden, H. D.
1974-01-01
Experimental and analytical natural frequencies, nodal patterns, and typical modal displacements for a corrugated, flexibly supported, heat-shield panel are discussed. Good correlation was found between the experimental data and NASTRAN analytical results for the corrugated panel over a relatively wide frequency spectrum covered in the investigation. Of the two experimental techniques used for mode shape and displacement measurements (a noncontacting displacement sensor system and a holographic technique using a helium-neon, continuous-wave laser), the holographic technique was found, in the present investigation, to be faster and better suited for determining a large number of complex nodal patterns of the corrugated panel.
Exact analytical solution to a transient conjugate heat-transfer problem
NASA Technical Reports Server (NTRS)
Sucec, J.
1973-01-01
An exact analytical solution is found for laminar, constant-property, slug flow over a thin plate which is also convectively cooled from below. The solution is found by means of two successive Laplace transformations when a transient in the plate and the fluid is initiated by a step change in the fluid inlet temperature. The exact solution yields the transient fluid temperature, surface heat flux, and surface temperature distributions. The results of the exact transient solution for the surface heat flux are compared to the quasi-steady values, and a criterion for the validity of the quasi-steady results is found. Also the effect of the plate coupling parameter on the surface heat flux are investigated.
ERIC Educational Resources Information Center
van Rooij, Iris; Schactman, Alissa; Kadlec, Helena; Stege, Ulrike
2006-01-01
The Euclidean Traveling Salesperson Problem (E-TSP) is a useful task to study how humans optimize when faced with computational intractability. It has been found that humans are capable of finding high-quality solutions for E-TSP in a relatively short time and with seemingly little cognitive effort. This observation has led to two general…
Educational Reform as a Dynamic System of Problems and Solutions: Towards an Analytic Instrument
ERIC Educational Resources Information Center
Luttenberg, Johan; Carpay, Thérèse; Veugelers, Wiel
2013-01-01
Large-scale educational reforms are difficult to realize and often fail. In the literature, the course of reform and problems associated with this are frequently discussed. The explanations and recommendations then provided are so diverse that it is difficult to gain a comprehensive overview of what factors are at play and how to take them into…
ERIC Educational Resources Information Center
Comer, Jonathan S.; Chow, Candice; Chan, Priscilla T.; Cooper-Vince, Christine; Wilson, Lianna A. S.
2013-01-01
Objective: Service use trends showing increased off-label prescribing in very young children and reduced psychotherapy use raise concerns about quality of care for early disruptive behavior problems. Meta-analysis can empirically clarify best practices and guide clinical decision making by providing a quantitative synthesis of a body of…
A cluster-analytic study of substance problems and mental health among street youths.
Adlaf, E M; Zdanowicz, Y M
1999-11-01
Based on a cluster analysis of 211 street youths aged 13-24 years interviewed in 1992 in Toronto, Ontario, Canada, we describe the configuration of mental health and substance use outcomes. Eight clusters were suggested: Entrepreneurs (n = 19) were frequently involved in delinquent activity and were highly entrenched in the street lifestyle; Drifters (n = 35) had infrequent social contact, displayed lower than average family dysfunction, and were not highly entrenched in the street lifestyle; Partiers (n = 40) were distinguished by their recreational motivation for alcohol and drug use and their below average entrenchment in the street lifestyle; Retreatists (n = 32) were distinguished by their high coping motivation for substance use; Fringers (n = 48) were involved marginally in the street lifestyle and showed lower than average family dysfunction; Transcenders (n = 21), despite above average physical and sexual abuse, reported below average mental health or substance use problems; Vulnerables (n = 12) were characterized by high family dysfunction (including physical and sexual abuse), elevated mental health outcomes, and use of alcohol and other drugs motivated by coping and escapism; Sex Workers (n = 4) were highly entrenched in the street lifestyle and reported frequent commercial sexual work, above average sexual abuse, and extensive use of crack cocaine. The results showed that distress, self-esteem, psychotic thoughts, attempted suicide, alcohol problems, drug problems, dual substance problems, and dual disorders varied significantly among the eight clusters. Overall, the findings suggest the need for differential programming. The data showed that risk factors, mental health, and substance use outcomes vary among this population. Also, for some the web of mental health and substance use problems is inseparable. PMID:10548440
Transport synthetic acceleration for long-characteristics assembly-level transport problems
Zika, M.R.; Adams, M.L.
2000-02-01
The authors apply the transport synthetic acceleration (TSA) scheme to the long-characteristics spatial discretization for the two-dimensional assembly-level transport problem. This synthetic method employs a simplified transport operator as its low-order approximation. Thus, in the acceleration step, the authors take advantage of features of the long-characteristics discretization that make it particularly well suited to assembly-level transport problems. The main contribution is to address difficulties unique to the long-characteristics discretization and produce a computationally efficient acceleration scheme. The combination of the long-characteristics discretization, opposing reflecting boundary conditions (which are present in assembly-level transport problems), and TSA presents several challenges. The authors devise methods for overcoming each of them in a computationally efficient way. Since the boundary angular data exist on different grids in the high- and low-order problems, they define restriction and prolongation operations specific to the method of long characteristics to map between the two grids. They implement the conjugate gradient (CG) method in the presence of opposing reflection boundary conditions to solve the TSA low-order equations. The CG iteration may be applied only to symmetric positive definite (SPD) matrices; they prove that the long-characteristics discretization yields an SPD matrix. They present results of the acceleration scheme on a simple test problem, a typical pressurized water reactor assembly, and a typical boiling water reactor assembly.
ERIC Educational Resources Information Center
Heckel, Robert V.; Mandell, Elizabeth
1981-01-01
A factor analytic study of the behavioral and demographic variables that describe male and female juvenile offenders in a southern correctional facility identified 10 factors for females and six for males. Items clustered much as anticipated for both groups, with family conflicts and individual neurotic traits forming clusters. (Author)
Goals and Characteristics of Long-Term Care Programs: An Analytic Model.
ERIC Educational Resources Information Center
Braun, Kathryn L.; Rose, Charles L.
1989-01-01
Used medico-social analytic model to compare five long-term care programs: Skilled Nursing Facility-Intermediate Care Facility (SNF-ICF) homes, ICF homes, foster homes, day hospitals, and home care. Identified similarities and differences among programs. Preliminary findings suggest that model is useful in the evaluation and design of long-term…
Pain beliefs and problems in functioning among people with arthritis: a meta-analytic review.
Jia, Xiaojun; Jackson, Todd
2016-10-01
In this meta-analysis, we evaluated overall strengths of relation between beliefs about pain, health, or illness and problems in functioning (i.e., functional impairment, affective distress, pain severity) in osteoarthritis and rheumatoid arthritis samples as well as moderators of these associations. In sum, 111 samples (N = 17,365 patients) met inclusion criteria. On average, highly significant, medium effect sizes were observed for associations between beliefs and problems in functioning but heterogeneity was also inflated. Effect sizes were not affected by arthritis subtype, gender, or age. However, pain belief content emerged as a significant moderator, with larger effect sizes for studies in which personal incapacity or ineffectiveness in controlling pain was a content theme of belief indices (i.e., pain catastrophizing, helplessness, self-efficacy) compared to those examining locus of control and fear/threat/harm beliefs. Furthermore, analyses of longitudinal study subsets supported the status of pain beliefs risk factors for later problems in functioning in these groups. PMID:27506911
NASA Astrophysics Data System (ADS)
Yoon, Heojeong; Woo, Ae Ja; Treagust, David; Chandrasegaran, AL
2014-01-01
The efficacy of problem-based learning (PBL) in an analytical chemistry laboratory course was studied using a programme that was designed and implemented with 20 students in a treatment group over 10 weeks. Data from 26 students in a traditional analytical chemistry laboratory course were used for comparison. Differences in the creative thinking ability of students in both the treatment and control groups were evaluated before and at the end of the implementation of the programme, using the Torrance Tests of Creative Thinking. In addition, changes in students' self-regulated learning skills using the Self-Regulated Learning Interview Schedule (SRLIS) and their self-evaluation proficiency were evaluated. Analysis of covariance showed that the creative thinking ability of the treatment group had improved statistically significantly after the PBL course (p < 0.001) compared to that of the students in the comparison group. PBL was shown to have a positive effect on creative thinking ability. The SRLIS test showed that students in the treatment group used self-regulated learning strategies more frequently than students in the comparison group. According to the results of the self-evaluation, students became more positive and confident in problem-solving and group work as the semester progressed. Overall, PBL was shown to be an effective pedagogical instructional strategy for enhancing chemistry students' creative thinking ability, self-regulated learning skills and self-evaluation.
Semi-analytical solution to the 2014 eddy current benchmark problem
NASA Astrophysics Data System (ADS)
Miorelli, Roberto; Reboud, Christophe; Voulgaraki, Charitini; Poulakis, Nikolaos; Theodoulidis, Theodoros
2015-03-01
This work proposes a solution to the 2014 eddy current testing benchmark, published by the WFNDEC and proposed by the authors. The aim of this benchmark is to provide reference data for eddy current testing configurations involving magnetic sensors -here Hall sensors- as receivers, as they present some advantages in terms of resolution and sensitivity. After a presentation of the benchmark cases, the theoretical approach used to solve the equivalent electromagnetic problem is detailed and a alternative computation of eddy current signals is proposed. Then, simulations are quantitatively compared to experimental data in each case and the results are discussed.
An Analytical Singularity-Free Solution to the J2 Perturbation Problem
NASA Technical Reports Server (NTRS)
Bond, V. R.
1979-01-01
The development of a singularity-free solution of the J2 problem in satellite theory is presented. The procedure resembles that of Lyndane who rederives Brouwer's satellite theory using Poincare elements. A comparable procedure is used in this report in which the satellite theory of Scheifele, who used elements similar to the Delaunay elements but in the extended phase space, is rederived using Poincare elements also in the extended phase space. Only the short-period effects due to J2 are included.
A general analytical solution to the geometrical problem of field matching in radiotherapy
Hernandez, V.; Arenas, M.; Pons, F.; Sempau, J.
2009-09-15
Purpose: Several authors studied the problem of geometrical matching of fields produced by medical linear accelerators. However, a general solution has yet to be published. Currently available solutions are based on parallelism arguments. This study provides a general solution, considering not only parallelism but also field sizes. Methods: A fixed field with arbitrary field size, gantry, collimator, and couch angle is considered, and another field with a fixed gantry angle is matched to it. A single reference system attached to the treatment couch is used, and two approaches are followed. In the first approach, fixed field sizes are assumed and parallelism of the adjacent field-side planes is imposed. In the second approach, fixed isocenter positions are considered and both parallelism and coincidence between field-side planes are required. Results: When fixed field sizes are assumed, rotation angles are obtained; however, the isocenters may need to be shifted to make side planes coincident and therefore achieve a proper match. When fixed isocenter positions are considered, solutions for all parameters, including the field size, are obtained and an exact geometrical match is achieved. Conclusions: General expressions to the field-matching problem are found for the two approaches followed, fixed field sizes, and fixed isocenter positions. These results can be applied to any treatment technique and can easily be implemented in modern treatment planning systems.
NASA Astrophysics Data System (ADS)
Shein, E. V.
2015-07-01
The formation, development, and some problems of the current physically based models of water and solute transfer are considered in this review. These models appeared about a half century ago. They were based on the basic laws of soil physics and other branches of soil science (laws of balance, transfer, diffusion, hydrodynamic dispersion, etc.) described by the corresponding equations and programs and supported by the experimental data in the form of physically based parameters. At present, one of the main problems in the development, adaptation, and application of these models is that the current and future mathematical models should rest upon the experimental support with a clear physical basis characterizing the nature of the phenomenon described. This experimental support enables creating research models, drawing conceptual conclusions, and, hence, understanding, analyzing, and managing soil processes. This is apparently possible only if the set of methods for the experimental support of models is substantiated, preferably in direct physical experiments and under field conditions close to the future model prognoses.
Analytic Approach to the Cloud-in-Cloud Problem for Non-Gaussian Density Fluctuations
NASA Astrophysics Data System (ADS)
Inoue, Kaiki Taro; Nagashima, Masahiro
2002-07-01
We revisit the cloud-in-cloud problem for non-Gaussian density fluctuations. We show that the extended Press-Schechter (EPS) formalism for non-Gaussian fluctuations has a flaw in describing mass functions regardless of the type of filtering. As an example, we consider non-Gaussian models in which density fluctuations at a point obey a χ2 distribution with ν degrees of freedom. We find that mass functions predicted by using an integral formula proposed by Jedamzik and Yano, Nagashima, and Gouda, properly taking into account correlation between objects at different scales, deviate from those predicted by using the EPS formalism, especially for strongly non-Gaussian fluctuations. Our results for the mass function at large mass scales are consistent with those by Avelino and Viana obtained from numerical simulations.
NASA Astrophysics Data System (ADS)
Chen, Yao; Balani, Kantesh; Agarwal, Arvind
2008-01-01
This research presents an analytical method to investigate the effect of volume fraction and the number of outer walls of multiwalled carbon nanotube (MWNT) reinforcement on load carrying capability in the aluminum oxide matrix. Interfacial shear stress transfer and energy dissipation have been estimated using the Cox model. Critical energy release rate for the debonding of MWNT from the matrix is also estimated based on the crack deflection. The computed results sufficiently manifest that MWNT pullout and crack deflection contributes greatly to improved fracture toughness of carbon nanotube reinforced aluminum oxide nanocomposites.
Language Problems Among Abused and Neglected Children: A Meta-Analytic Review.
Sylvestre, Audette; Bussières, Ève-Line; Bouchard, Caroline
2016-02-01
Research data show that exposure to abuse and neglect has detrimental effects on a child's language development. In this meta-analysis, we analyze studies (k = 23), to compare the language skills (receptive language, expressive language, pragmatics) of children who have experienced abuse and/or neglect with the language skills of children who have not experienced abuse and/or neglect and to examine whether age or type of maltreatment moderate the relationship between maltreatment and language skills. Results confirm that the language skills of children who have experienced abuse and/or neglect are delayed when compared to children who have not experienced abuse and/or neglect. Compared to older children, young children seem particularly vulnerable to abuse and neglect. No significant differences were demonstrated concerning the type of maltreatment suffered by the child. These findings support the necessity of early detection of language problems in abused and neglected children as well as early intervention in order to implement interventions that will positively stimulate their development. PMID:26620719
Razzaghi, D; Hajiesmaeilbaigi, F; Ruzbehani, M
2012-08-31
Possible effects of amplified spontaneous emission on output pulse characteristics of a Q-switched laser are discussed within the framework of a semi-analytical approach. It is shown that output energy decreases almost exponentially with average path length of the spontaneously emitted photons which in turn depends on geometrical specification and active medium properties as well as on optical finishing of the surfaces (for solid-state lasers). Optimal coupling dependence on the average path length is also investigated and shown to increase with average path length increment. (control of laser radiation parameters)
NASA Technical Reports Server (NTRS)
Rainey, A. G.; Hanson, P. W.; Martin, D. J.
1958-01-01
The static aeroelastic divergence characteristics of a delta-planform model of the canard control surface of a proposed air-to-ground missile have been studied both analytically and experimentally in the Mach number range from 0.6 to 3.0. The experiments indicated that divergence occurred at a nearly constant value of dynamic pressure at Mach numbers up to 1.2. At higher Mach numbers somewhat higher values of dynamic pressure were required to produce divergence. The analysis and the experiment indicate that the camber stiffness of the control surface and the stiffness of the control actuator are both important in divergence of surfaces of this type.
NASA Technical Reports Server (NTRS)
Purvis, C. K.; Stevens, N. J.; Oglebay, J. C.
1977-01-01
An understanding of the behavior of materials, of dielectrics in particular, under charged particle bombardment is essential to the prediction and prevention of the adverse effects of spacecraft charging. A one-dimensional model for charging of samples in a test facility was used in conjunction with experimental data taken to develop "material charging characteristics" for silvered Teflon. These characteristics were then used in a one-dimensional model for charging in space to examine expected response. Relative charging rates as well as relative charging levels for silvered Teflon and metal are discussed.
A lunar-based analytical laboratory and contamination problems in analysis of Moon and Mars samples
NASA Astrophysics Data System (ADS)
Gehrke, Charles W.
1997-07-01
A summary follows of our experiences and techniques used in the analysis of samples from Apollo Missions 11 to 17. The studies were conducted at the Ames Research Center, Moffett Field, CA, the University of Missouri, Columbia, MO, and the University of Maryland, College Park, MD, 1969 - 1974. Our search was directed to water-extractable compounds with emphasis on amino acids. Gas chromatography, ion-exchange chromatography and gas chromatography combined with mass spectrometry were used for the analysis. It is our conclusion that amino acids are not present in the lunar regolith above the background levels of our investigation (ca. 1 - 3 ng/g). The scientific debate has become heated that primitive life existed on Mars 3.6 billion years ago as reported by the NASA-Stanford team led to David McKay. Mars is destined to receive humans early in the 21st Century, preceded by many international missions to Space Station Freedom and robotic missions to the Moon and Mars. First, we must `learn to live in space'. The Moon presents a base that provides the opportunities and challenges to assemble the international interdisciplinary intellectual scientific teams and partners with many disciplines to make the next step before human exploration of Mars and the search for evidence in Martian soil and samples returned to Earth laboratories. Our experiences learned in Moon analysis will be useful in Mars exploration and returned sample study. Sensitivity at the nanogram/gram level and selectivity of analysis are highly essential. As these figures show contamination of samples is a most serious problem. However with the use of ultraclean techniques in a 100 clean room contamination can be avoided. Our speck of dust, a tiny fragment of cigarette smoke, a particle of dandruff, a droplet of saliva, all can make your results questionable. In addition, the extraction of life molecules as amino acids from the Lunar samples was a difficult process and I am sure the same difficulties
Characteristics of problem drinking in an urban South American indigenous population.
Seale, J Paul; Shellenberger, Sylvia; Sanchez, Nelia; Vogel, Robert L; Villalobos, Elibeth; Girton, Fred S; Seale, Dana M; Okosun, Ike S
2010-11-01
This 2002 Medcen Foundation-funded study explored characteristics of problem drinking among 211 urban Venezuelan Native Americans of Arawak origin. Prevalence of problem drinking using Alcohol Use Disorders Identification Tests was 88.5% among men and 17.3% among women. Periodic binge drinking was marked by loss of control, failure to meet obligations, and alcohol-related trauma. Focus group participants noted that previous occasional binge drinking by men has been replaced by frequent male and female heavy weekend drinking, violence, and death. Limitations and implications are discussed. Awareness of high levels of problem drinking and desire for assistance present compelling mandates for community intervention efforts. PMID:20388009
NASA Technical Reports Server (NTRS)
Frink, N. T.; Lamar, J. E.
1980-01-01
A systematic water-tunnel study was made to determine the vortex breakdown characteristics of 43 strakes. The strakes were mounted on a 1/2-scale model of a Langley Research Center general research fighter fuselage model with a 44deg leading-edge-sweep trapezoidal wing. The analytically designed strake shapes provided examples of the effects of the primary design parameters (size, span, and slenderness) on vortex breakdown characteristics. These effects were analyzed in relation to the respective strake leading-edge suction distributions. Included were examples of the effects of detailed strake planform shaping. It was concluded that, consistent with the design criterion, those strakes with leading-edge suction distributions which increase more rapidly near, and have a higher value at, the spanwise tip of the strake produce a more stable vortex.
Investigation into the effect of beam shape on melt pool characteristics using analytical modelling
NASA Astrophysics Data System (ADS)
Ahmed, N.; Voisey, K. T.; McCartney, D. G.
2010-05-01
An established analytical model is used to simulate an extended laser beam. Multiple Gaussian sources are superimposed to form a rectangular beam and results are compared with a single circular Gaussian source model as well as experimental results from a high power diode laser with a rectangular beam. Melt depth and melt pool profile and progression have been predicted by modeling, which are compared with experimental results from melting of Inconel 625. The model produced is shown to give a reasonable prediction of melt pool shape and can be usefully employed to help optimise overlap required for laser surface processing applications. The value of absorptivity used in the model can be used as a fitting parameter to optimise the match between experimental and predicted results.
Lee, Erica H; Zhou, Qing; Ly, Jennifer; Main, Alexandra; Tao, Annie; Chen, Stephen H
2014-04-01
Using data from a socioeconomically diverse sample of Chinese American children (n = 258, aged 6-9 years) in immigrant families, we examined the concurrent relations among neighborhood economic disadvantage and concentration of Asian residents, parenting styles, and Chinese American children's externalizing and internalizing problems. Neighborhood characteristics were measured with 2000 U.S. Census tract-level data, parents (mostly mothers) rated their own parenting styles, and parents and teachers rated children's behavioral problems. Path analysis was conducted to test two hypotheses: (a) parenting styles mediate the relations between neighborhood characteristics and children's behavioral problems, and (b) children's behavioral problems mediate the relations between neighborhood and parenting styles. We found that neighborhood Asian concentration was positively associated with authoritarian parenting, which in turn was associated with Chinese American children's higher externalizing and internalizing problems (by parents' reports). In addition, neighborhood economic disadvantage was positively related to children's externalizing problems (by parents' reports), which in turn predicted lower authoritative parenting. The current results suggest the need to consider multiple pathways in the relations among neighborhood, family, and child adjustment, and they have implications for the prevention and intervention of behavioral problems in Chinese American children. PMID:24041263
Investigating Grade Nine Textbook Problems for Characteristics Related to Mathematical Literacy
ERIC Educational Resources Information Center
Gatabi, Abolfazl Rafiepour; Stacey, Kaye; Gooya, Zahra
2012-01-01
This study presents a content analysis of the new Iranian Grade 9 mathematics textbook and two Australian Year 9 mathematics textbooks, examining the extent to which the problems show characteristics associated in the literature with promoting mathematical literacy. The new Iranian book was produced to meet a range of needs including several well…
ERIC Educational Resources Information Center
Johnson, Cynthia R.; Turner, Kylan; Stewart, Patricia A.; Schmidt, Brianne; Shui, Amy; Macklin, Eric; Reynolds, Anne; James, Jill; Johnson, Susan L.; Manning Courtney, Patty; Hyman, Susan L.
2014-01-01
Many children with autism spectrum disorders (ASD) have co-occurring feeding problems. However, there is limited knowledge about how these feeding habits are related to other behavioral characteristics ubiquitous in ASD. In a relatively large sample of 256 children with ASD, ages 2-11, we examined the relationships between feeding and mealtime…
Investigating grade nine textbook problems for characteristics related to mathematical literacy
NASA Astrophysics Data System (ADS)
Rafiepour Gatabi, Abolfazl; Stacey, Kaye; Gooya, Zahra
2012-12-01
This study presents a content analysis of the new Iranian Grade 9 mathematics textbook and two Australian Year 9 mathematics textbooks, examining the extent to which the problems show characteristics associated in the literature with promoting mathematical literacy. The new Iranian book was produced to meet a range of needs including several well aligned with mathematical literacy for all students. Australia was selected as the comparison country because of its relatively high international achievement in mathematical literacy. Three comparable chapters in each book were analysed for these characteristics. When considering the percentages of problems showing each characteristic, there was considerable similarity between the textbooks. However, the Australian mathematics textbooks contain many more problems than the Iranian textbook and each chapter includes problems in a diverse range of contexts and the mathematical tasks range from simple applications of formulas to real world modelling although of a constrained nature. With many fewer problems, the Iranian textbook has considerably less diversity of context and very little opportunity for students to engage in mathematical modelling, the key process of mathematical literacy.
Jiang, Liuwei; Marcus, R Kenneth
2016-02-01
Capillary-channeled polymer (C-CP) fiber stationary phases are finding utility in the realms of protein analytics as well as downstream processing. We have recently described the modification of poly(ethylene terephthalate) (PET) C-CP fibers to affect amine-rich phases for the weak anion-exchange (WAX) separation of proteins. Polyethylenimine (PEI) is covalently coupled to the PET surface, with subsequent cross-linking imparted by treatment with 1,4-butanediol diglycidyl ether (BUDGE). These modifications yield vastly improved dynamic binding capacities over the unmodified fibers. We have also previously employed native (unmodified) nylon 6 C-CP fibers as weak anion/cation-exchange (mixed-mode) and hydrophobic interaction chromatography (HIC) phases for protein separations. Polyamide, nylon 6, consists of amide groups along the polymer backbone, with primary amines and carboxylic acid end groups. The analytical separation characteristics of these three amine-based C-CP fiber phases are compared here. Each of the C-CP fiber columns in this study was shown to be able to separate a bovine serum albumin/hemoglobin/lysozyme mixture at high mobile phase linear velocity (∼70 mm s(-1)) but with different elution characteristics. These differences reflect the types of protein-surface interactions that are occurring, based on the active group composition of the fiber surfaces. This study provides important fundamental understanding for the development of surface-modified C-CP fiber columns for protein separation. PMID:26345444
Methodical and pre-analytical characteristics of a multiplex cancer biomarker immunoassay
Hermann, Natalie; Dreßen, Katja; Schildberg, Frank A; Jakobs, Christopher; Holdenrieder, Stefan
2014-01-01
AIM: To test the methodical and pre-analytical performance of a new multiplex cancer biomarker panel using magnetic beads. METHODS: The MILLIPLEX® MAP Human Circulating Cancer Biomarker Magnetic Bead Panel 1 comprises the tumor markers carcinoembryonic antigen, alpha-fetoprotein, total prostate-specific antigen, cancer antigen 15-3, cancer antigen 19-9, cancer antigen 125, cytokeratine 19-fragment, β-human chorionic gonadotropin, human epididymis protein 4, osteopontin, prolactin, the cell death and angiogenesis markers soluble Fas, soluble Fas-ligand, tumor necrosis factor related apoptosis-inducing ligand, vascular endothelial growth factor and the immunological markers interleukin-6 (IL-6), IL-8, tumor necrosis factor-α, transforming growth factor α, fibroblast growth factor-2, macrophage migration inhibitory factor, leptin, hepatocyte growth factor, and stem cell factor. We determined intra- and inter-assay imprecision as well as dilution linearity using quality controls and serum pools. Furthermore, the stability of the 24 biomarkers examined in this panel was ascertained by testing the influence of different storage temperatures and time span before centrifugation. RESULTS: For all markers measured in the synthetic internal quality controls, the intra-assay imprecision ranged between 2.26% and 9.41%, while for 20 of 24 measured markers in the physiological serum pools, it ranged between 1.68% and 12.87%. The inter-assay imprecision ranged between 1.48%-17.12% for 23 biomarkers in synthetic, and between 4.59%-23.88% for 18 biomarkers in physiological quality controls. Here, single markers with very low concentration levels had increased imprecision rates. Dilution linearity was acceptable (70%-130% recovery) for 20 biomarkers. Regarding pre-analytical influencing factors, most markers were stable if blood centrifugation was delayed or if serum was stored for up to 24 h at 4 °C and 25 °C after centrifugation. Comparable results were obtained in serum and
Analytical investigation in bending characteristic of twisted stacked-tape cable conductor
NASA Astrophysics Data System (ADS)
Takayasu, Makoto; Chiesa, Luisa
2015-12-01
An analytical model to evaluate bending strains of a twisted stack-tape cable (TSTC) conductor has been developed. Through a comparison with experimental results obtained for a soldered 32-tape YBCO TSTC conductor, it has been found that a Perfect-Slip Model (PSM) taking into account the slipping between tapes in a stacked-tape cable during bending gives much better estimation of the bending performance compared to a No-Slip Model (NSM). In the PSM case the tapes can slip so that the internal longitudinal axial strain can be released. The longitudinal strains of compression and tension regions along the tape are balanced in one twist-pitch and cancel out evenly in a long cable. Therefore, in a cable the strains due to bending can be minimized. This is an important advantage of a TSTC conductor. The effect of the cable diameter size on the bending strain is also expected to be minor, and all tapes composing a TSTC conductor have the same strain response under bending, therefore the cable critical current can be characterized from a single tape behaviour.
Analytical derivation of thermodynamic characteristics of lipid bilayer from a flexible string model
NASA Astrophysics Data System (ADS)
Mukhin, Sergei I.; Baoukina, Svetlana
2005-06-01
We introduce a flexible string model of the hydrocarbon chain and derive an analytical expression for the lateral pressure profile across the hydrophobic core of the membrane. The pressure profile influences the functioning of the embedded proteins and is difficult to measure experimentally. In our model the hydrocarbon chain is represented as a flexible string of finite thickness with a given bending rigidity. In the mean-field approximation we substitute the entropic repulsion between neighboring chains in a lipid membrane by an effective potential. The effective potential is determined self-consistently. The arbitrary chain conformation is expanded over eigenfunctions of the self-adjoint operator of the chain energy density. The lateral pressure distribution across the bilayer is calculated using the path integral technique. We found that the pressure profile is mainly formed by the sum of the partial contributions of a few discrete lowest-energy “eigenconformations.” The dependences on temperature and area per lipid of the lateral pressure produced by the hydrocarbon chains are found. We also calculated the chain contribution to the area compressibility modulus and the temperature coefficient of area expansion.
Experimental and analytical transonic flutter characteristics of a geared-elevator configuration
NASA Technical Reports Server (NTRS)
Ruhlin, C. L.; Doggett, R. V., Jr.; Gregory, R. A.
1980-01-01
The flutter model represented the aft fuselage and empennage of a proposed supersonic transport airplane and had an all movable horizontal tail with a geared elevator. It was tested mounted from a sting in the transonic dynamics tunnel. Symmetric flutter boundaries were determined experimentally at Mach numbers from 0.7 to 1.14 for a geared elevator configuration (gear ratio of 2.8 to 1.0) and an ungeared elevator configuration (gear ratio of 1.0 to 1.0). Gearing the elevator increased the experimental flutter dynamic pressures about 20 percent. Flutter calculations were made for the geared elevator configuration by using two analytical methods based on subsonic lifting surface theory. Both methods analyzed the stabilizer and elevator as a single, deforming surface, but one method also allowed the elevator to be analyzed as hinged from the stabilizer. All analyses predicted lower flutter dynamic pressures than experiment with best agreement (within 12 percent) for the hinged elevator method. Considering the model as mounted from a flexible rather than rigid sting in the analyses, had only a slight effect on the flutter results but was significant in that a sting related vibration mode was identified as a potentially flutter critical mode.
NASA Astrophysics Data System (ADS)
Zlotnik, V. A.; Ledder, G.; Kacimov, A. R.
2014-12-01
Disposal of excessive runoff or treated sewage into wadis and ephemeral streams is a common practice and an important hydrological problem in many Middle Eastern countries. While chemical and biological properties of the injected treated wastewater may be different from those of the receiving aquifer, the density contrast between the two fluids can be small. Therefore, studies of the fluid interface for variable density fluids or water intrusion are not directly relevant in many Managed Aquifer Recharge (MAR) problems. Other factors, such as the transient nature of injection and lack of detailed aquifer information must be considered. The disposed water reaching the water table through the vadose zone creates groundwater mounds, deforms the original water table, and develops finite-size convex-concave lenses of treated water over receiving water. After cessation of infiltration, these mounds flatten, water levels become horizontal, and infiltrated water becomes fully embedded in the receiving aquifer. The shape of the treated water body is controlled by the aquifer parameters, the magnitude of ambient flow, and the duration, rate, and cyclicity of infiltration. In case of limited aquifer data, advective transport modeling offers the most appropriate tools for predicting plume shapes over time, but surprisingly little work has been done on this important 3D flow problem. We investigate the lateral and vertical spreading of infiltrated water combining techniques of spatial velocity analyses by Zlotnik and Ledder (1992, 1993) with particle tracking. This approach allows for evaluating the geometry of the plume and the protection zone, the flow development phases, and other temporal and spatial effects and results can be used in conditions of limited data availability and quality. (Funding was provided by the USAID, DAI Subcontract 1001624-12S-19745)
Faraji, Obeidollah; Ramazani, Abbas Ali; Hedaiati, Pouria; Aliabadi, Ali; Elhamirad, Samira; Valiee, Sina
2015-01-01
Background: Many factors influence the organizational commitment of employees. One of these factors is job designing since it affects the attitude, beliefs, and feelings of the organization employees. Objectives: We aimed to determine the relationship between job characteristics and organizational commitment among the employees of hospitals. Patients and Methods: In this descriptive and correlational study, 152 Iranian employees of the hospitals (physicians, nurses, and administrative staff) were selected through stratified random sampling. Data gathered using 3-part questionnaire of “demographic information”, “job characteristics model,” and “organizational commitment,” in 2011. Study data were analyzed using SPSS v. 16. Results: There was significant statistical correlation between organizational commitment and variables of educational level (P = 0.001) and job category (P = 0.001). Also, a direct and significant correlation existed between motivating potential score and job feedback on one hand and organizational commitment on the other hand (P = 0.014). Conclusions: According to the results, managers of the hospitals should increase staff’s commitment through paying attention to proper job designing. PMID:26734472
Jang, H.D.; Swaisgood, H.E. )
1990-12-01
Interaction of calcium with casein submicelles was investigated in CaCl2 and calcium phosphate buffers and with synthetic milk salt solutions using the technique of analytical affinity chromatography. Micelles that had been prepared by size exclusion chromatography with glycerolpropyl controlled-pore glass from fresh raw skim milk that had never been cooled, were dialyzed at room temperature against calcium-free imidazole buffer, pH 6.7. Resulting submicelles were covalently immobilized on succinamidopropyl controlled-pore glass (300-nm pore size). Using 45Ca to monitor the elution retardation, the affinity of free Ca2+ and calcium salt species was determined at temperatures of 20 to 40 degrees C and pH 6.0 to 7.5. Increasing the pH in this range or increasing the temperature strengthened the binding of calcium to submicelles, similar to previous observations with individual caseins. However, the enthalpy change obtained from the temperature dependence was considerably greater than that reported for alpha s1- and beta-caseins. Furthermore, the elution profiles for 45Ca in milk salt solutions were decidedly different from those in CaCl2 or calcium phosphate buffers and the affinities were also greater. For example, at pH 6.7 and 30 degrees C the average dissociation constant for the submicelle-calcium complex is 0.074 mM for CaCl2 and calcium phosphate buffers, vs 0.016 mM for the milk salt solution. The asymmetric frontal boundaries and higher average affinities observed with milk salts may be due to binding of calcium salts with greater affinity in addition to the binding of free Ca2+ in these solutions.
Pinsky, Benjamin A.; Sahoo, Malaya K.; Sandlund, Johanna; Kleman, Marika; Kulkarni, Medha; Grufman, Per; Nygren, Malin; Kwiatkowski, Robert; Baron, Ellen Jo; Tenover, Fred; Denison, Blake; Higuchi, Russell; Van Atta, Reuel; Beer, Neil Reginald; Carrillo, Alda Celena; Naraghi-Arani, Pejman; Mire, Chad E.; Ranadheera, Charlene; Grolla, Allen; Lagerqvist, Nina; Persing, David H.
2015-01-01
Background The recently developed Xpert® Ebola Assay is a novel nucleic acid amplification test for simplified detection of Ebola virus (EBOV) in whole blood and buccal swab samples. The assay targets sequences in two EBOV genes, lowering the risk for new variants to escape detection in the test. The objective of this report is to present analytical characteristics of the Xpert® Ebola Assay on whole blood samples. Methods and Findings This study evaluated the assay’s analytical sensitivity, analytical specificity, inclusivity and exclusivity performance in whole blood specimens. EBOV RNA, inactivated EBOV, and infectious EBOV were used as targets. The dynamic range of the assay, the inactivation of virus, and specimen stability were also evaluated. The lower limit of detection (LoD) for the assay using inactivated virus was estimated to be 73 copies/mL (95% CI: 51–97 copies/mL). The LoD for infectious virus was estimated to be 1 plaque-forming unit/mL, and for RNA to be 232 copies/mL (95% CI 163–302 copies/mL). The assay correctly identified five different Ebola viruses, Yambuku-Mayinga, Makona-C07, Yambuku-Ecran, Gabon-Ilembe, and Kikwit-956210, and correctly excluded all non-EBOV isolates tested. The conditions used by Xpert® Ebola for inactivation of infectious virus reduced EBOV titer by ≥6 logs. Conclusion In summary, we found the Xpert® Ebola Assay to have high analytical sensitivity and specificity for the detection of EBOV in whole blood. It offers ease of use, fast turnaround time, and remote monitoring. The test has an efficient viral inactivation protocol, fulfills inclusivity and exclusivity criteria, and has specimen stability characteristics consistent with the need for decentralized testing. The simplicity of the assay should enable testing in a wide variety of laboratory settings, including remote laboratories that are not capable of performing highly complex nucleic acid amplification tests, and during outbreaks where time to detection
Pinsky, Benjamin A.; Sahoo, Malaya K.; Sandlund, Johanna; Kleman, Marika; Kulkarni, Medha; Grufman, Per; Nygren, Malin; Kwiatkowski, Robert; Baron, Ellen Jo; Tenover, Fred; Denison, Blake; Higuchi, Russell; Van Atta, Reuel; Beer, Neil Reginald; Carrillo, Alda Celena; Naraghi-Arani, Pejman; Mire, Chad E.; Ranadheera, Charlene; Grolla, Allen; Lagerqvist, Nina; Persing, David H.
2015-11-12
The recently developed Xpert® Ebola Assay is a novel nucleic acid amplification test for simplified detection of Ebola virus (EBOV) in whole blood and buccal swab samples. The assay targets sequences in two EBOV genes, lowering the risk for new variants to escape detection in the test. The objective of this report is to present analytical characteristics of the Xpert® Ebola Assay on whole blood samples. Our study evaluated the assay’s analytical sensitivity, analytical specificity, inclusivity and exclusivity performance in whole blood specimens. EBOV RNA, inactivated EBOV, and infectious EBOV were used as targets. The dynamic range of the assay, the inactivation of virus, and specimen stability were also evaluated. The lower limit of detection (LoD) for the assay using inactivated virus was estimated to be 73 copies/mL (95% CI: 51–97 copies/mL). The LoD for infectious virus was estimated to be 1 plaque-forming unit/mL, and for RNA to be 232 copies/mL (95% CI 163–302 copies/mL). The assay correctly identified five different Ebola viruses, Yambuku-Mayinga, Makona-C07, Yambuku-Ecran, Gabon-Ilembe, and Kikwit-956210, and correctly excluded all non-EBOV isolates tested. The conditions used by Xpert® Ebola for inactivation of infectious virus reduced EBOV titer by ≥6 logs. In conclusion, we found the Xpert® Ebola Assay to have high analytical sensitivity and specificity for the detection of EBOV in whole blood. It offers ease of use, fast turnaround time, and remote monitoring. The test has an efficient viral inactivation protocol, fulfills inclusivity and exclusivity criteria, and has specimen stability characteristics consistent with the need for decentralized testing. The simplicity of the assay should enable testing in a wide variety of laboratory settings, including remote laboratories that are not capable of performing highly complex nucleic acid amplification tests, and during outbreaks where time to detection is critical.
Pinsky, Benjamin A.; Sahoo, Malaya K.; Sandlund, Johanna; Kleman, Marika; Kulkarni, Medha; Grufman, Per; Nygren, Malin; Kwiatkowski, Robert; Baron, Ellen Jo; Tenover, Fred; et al
2015-11-12
The recently developed Xpert® Ebola Assay is a novel nucleic acid amplification test for simplified detection of Ebola virus (EBOV) in whole blood and buccal swab samples. The assay targets sequences in two EBOV genes, lowering the risk for new variants to escape detection in the test. The objective of this report is to present analytical characteristics of the Xpert® Ebola Assay on whole blood samples. Our study evaluated the assay’s analytical sensitivity, analytical specificity, inclusivity and exclusivity performance in whole blood specimens. EBOV RNA, inactivated EBOV, and infectious EBOV were used as targets. The dynamic range of the assay,more » the inactivation of virus, and specimen stability were also evaluated. The lower limit of detection (LoD) for the assay using inactivated virus was estimated to be 73 copies/mL (95% CI: 51–97 copies/mL). The LoD for infectious virus was estimated to be 1 plaque-forming unit/mL, and for RNA to be 232 copies/mL (95% CI 163–302 copies/mL). The assay correctly identified five different Ebola viruses, Yambuku-Mayinga, Makona-C07, Yambuku-Ecran, Gabon-Ilembe, and Kikwit-956210, and correctly excluded all non-EBOV isolates tested. The conditions used by Xpert® Ebola for inactivation of infectious virus reduced EBOV titer by ≥6 logs. In conclusion, we found the Xpert® Ebola Assay to have high analytical sensitivity and specificity for the detection of EBOV in whole blood. It offers ease of use, fast turnaround time, and remote monitoring. The test has an efficient viral inactivation protocol, fulfills inclusivity and exclusivity criteria, and has specimen stability characteristics consistent with the need for decentralized testing. The simplicity of the assay should enable testing in a wide variety of laboratory settings, including remote laboratories that are not capable of performing highly complex nucleic acid amplification tests, and during outbreaks where time to detection is critical.« less
NASA Astrophysics Data System (ADS)
Wailliez, Sébastien E.
2014-03-01
In the two-body model, time of flight between two positions can be expressed as a single-variable function and a variety of formulations exist. Lambert’s problem can be solved by inverting such a function. In this article, a method which inverts Lagrange’s flight time equation and supports the problematic 180° transfer is proposed. This method relies on a Householder algorithm of variable order. However, unlike other iterative methods, it is semi-analytical in the sense that flight time functions are derived analytically to second order vs. first order finite differences. The author investigated the profile of Lagrange’s elliptic flight time equation and its derivatives with a special focus on their significance to the behaviour of the proposed method and the stated goal of guaranteed convergence. Possible numerical deficiencies were identified and dealt with. As a test, 28 scenarios of variable difficulty were designed to cover a wide variety of geometries. The context of this research being the orbit determination of artificial satellites and debris, the scenarios are representative of typical such objects in Low-Earth, Geostationary and Geostationary Transfer Orbits. An analysis of the computational impact of the quality of the initial guess vs. that of the order of the method was also done, providing clues for further research and optimisations (e.g. asteroids, long period comets, multi-revolution cases). The results indicate fast to very fast convergence in all test cases, they validate the numerical safeguards and also give a quantitative assessment of the importance of the initial guess.
NASA Technical Reports Server (NTRS)
Simpson, Myles A.; Mathur, Gopal P.
1992-01-01
Measurements conducted on a DC-9 aircraft test section to define the shell and cavity modes of the fuselage, understand its structural-acoustic coupling characteristics, and measure its response to different types of acoustic and vibration excitations are reported. The data were processed to generate spatial plots and wavenumber maps of the shell acceleration and cabin acoustic pressure field. Analysis and interpretation of the spatial plots and wavenumber maps showed that the only structural-acoustic coupling occurred at 105 Hz between the N=2 circumferential structural mode and the (n=2, p=0) circumferential cavity mode. The fuselage response to vibration excitation was found to be dominated by modes whose order increases with frequency.
This manual provides the pesticide chemist with a systematic protocol for the quality control of analytical procedures and the problems that arise in the analysis of human or environmental media. It also serves as a guide to the latest and most reliable methodology available for ...
NASA Astrophysics Data System (ADS)
Liu, Wen-Chao; Yao, Jun; Chen, Zhang-Xin
2014-02-01
Based on Huang's accurate tri-sectional nonlinear kinematic equation (1997), a dimensionless simplified mathematical model for nonlinear flow in one-dimensional semi-infinite long porous media with low permeability is presented for the case of a constant flow rate on the inner boundary. This model contains double moving boundaries, including an internal moving boundary and an external moving boundary, which are different from the classical Stefan problem in heat conduction: The velocity of the external moving boundary is proportional to the second derivative of the unknown pressure function with respect to the distance parameter on this boundary. Through a similarity transformation, the nonlinear partial differential equation (PDE) system is transformed into a linear PDE system. Then an analytical solution is obtained for the dimensionless simplified mathematical model. This solution can be used for strictly checking the validity of numerical methods in solving such nonlinear mathematical models for flows in low-permeable porous media for petroleum engineering applications. Finally, through plotted comparison curves from the exact analytical solution, the sensitive effects of three characteristic parameters are discussed. It is concluded that with a decrease in the dimensionless critical pressure gradient, the sensitive effects of the dimensionless variable on the dimensionless pressure distribution and dimensionless pressure gradient distribution becomemore serious; with an increase in the dimensionless pseudo threshold pressure gradient, the sensitive effects of the dimensionless variable become more serious; the dimensionless threshold pressure gradient (TPG) has a great effect on the external moving boundary but has little effect on the internal moving boundary. [Figure not available: see fulltext.
NASA Astrophysics Data System (ADS)
Liu, Wen-Chao; Yao, Jun; Chen, Zhang-Xin
2014-01-01
Based on Huang's accurate tri-sectional nonlinear kinematic equation (1997), a dimensionless simplified mathematical model for nonlinear flow in one-dimensional semi-infinite long porous media with low permeability is presented for the case of a constant flow rate on the inner boundary. This model contains double moving boundaries, including an internal moving boundary and an external moving boundary, which are different from the classical Stefan problem in heat conduction: The velocity of the external moving boundary is proportional to the second derivative of the unknown pressure function with respect to the distance parameter on this boundary. Through a similarity transformation, the nonlinear partial differential equation (PDE) system is transformed into a linear PDE system. Then an analytical solution is obtained for the dimensionless simplified mathematical model. This solution can be used for strictly checking the validity of numerical methods in solving such nonlinear mathematical models for flows in low-permeable porous media for petroleum engineering applications. Finally, through plotted comparison curves from the exact analytical solution, the sensitive effects of three characteristic parameters are discussed. It is concluded that with a decrease in the dimensionless critical pressure gradient, the sensitive effects of the dimensionless variable on the dimensionless pressure distribution and dimensionless pressure gradient distribution become more serious; with an increase in the dimensionless pseudo threshold pressure gradient, the sensitive effects of the dimensionless variable become more serious; the dimensionless threshold pressure gradient (TPG) has a great effect on the external moving boundary but has little effect on the internal moving boundary.
NASA Technical Reports Server (NTRS)
Damerow, W. P.; Murtaugh, J. P.; Burggraf, F.
1972-01-01
The flow characteristics of turbine airfoil cooling system components were experimentally investigated. Flow models representative of leading edge impingement, impingement with crossflow (midchord cooling), pin fins, feeder supply tube, and a composite model of a complete airfoil flow system were tested. Test conditions were set by varying pressure level to cover the Mach number and Reynolds number range of interest in advanced turbine applications. Selected geometrical variations were studied on each component model to determine these effects. Results of these tests were correlated and compared with data available in the literature. Orifice flow was correlated in terms of discharge coefficients. For the leading edge model this was found to be a weak function of hole Mach number and orifice-to-impinged wall spacing. In the impingement with crossflow tests, the discharge coefficient was found to be constant and thus independent of orifice Mach number, Reynolds number, crossflow rate, and impingement geometry. Crossflow channel pressure drop showed reasonable agreement with a simple one-dimensional momentum balance. Feeder tube orifice discharge coefficients correlated as a function of orifice Mach number and the ratio of the orifice-to-approach velocity heads. Pin fin data was correlated in terms of equivalent friction factor, which was found to be a function of Reynolds number and pin spacing but independent of pin height in the range tested.
Learning and teaching in small groups: characteristics, benefits, problems and approaches.
Jones, R W
2007-08-01
Small group learning may be defined as a group of learners demonstrating three common characteristics; active participation, a specific task and reflection. This article provides an overview of small group learning and teaching, describes the characteristics of this form of small group work, benefits, problems, potential causes of less than optimal sessions, and summarises specific approaches. These include tutorials, free-discussion groups, brainstorming, snowballing, buzz groups, paired (or one-to-one) discussion, clinical teaching, simulations, seminars, plenary sessions, problem-based learning, team-based learning, role plays, games and IT approaches. The article concludes with an emphasis on the importance of the teacher and a check list for use when planning, teaching and evaluating a small group session. PMID:18020080
2011-01-01
The photocurrent in bilayer polymer photovoltaic cells is dominated by the exciton dissociation efficiency at donor/acceptor interface. An analytical model is developed for the photocurrent-voltage characteristics of the bilayer polymer/TiO2 photovoltaic cells. The model gives an analytical expression for the exciton dissociation efficiency at the interface, and explains the dependence of the photocurrent of the devices on the internal electric field, the polymer and TiO2 layer thicknesses. Bilayer polymer/TiO2 cells consisting of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and TiO2, with different thicknesses of the polymer and TiO2 films, were prepared for experimental purposes. The experimental results for the prepared bilayer MEH-PPV/TiO2 cells under different conditions are satisfactorily fitted to the model. Results show that increasing TiO2 or the polymer layer in thickness will reduce the exciton dissociation efficiency in the device and further the photocurrent. It is found that the photocurrent is determined by the competition between the exciton dissociation and charge recombination at the donor/acceptor interface, and the increase in photocurrent under a higher incident light intensity is due to the increased exciton density rather than the increase in the exciton dissociation efficiency. PMID:21711905
Russell, David F.; Neiman, Alexander B.; Lindner, Benjamin
2013-01-01
Stochastic signals with pronounced oscillatory components are frequently encountered in neural systems. Input currents to a neuron in the form of stochastic oscillations could be of exogenous origin, e.g. sensory input or synaptic input from a network rhythm. They shape spike firing statistics in a characteristic way, which we explore theoretically in this report. We consider a perfect integrate-and-fire neuron that is stimulated by a constant base current (to drive regular spontaneous firing), along with Gaussian narrow-band noise (a simple example of stochastic oscillations), and a broadband noise. We derive expressions for the nth-order interval distribution, its variance, and the serial correlation coefficients of the interspike intervals (ISIs) and confirm these analytical results by computer simulations. The theory is then applied to experimental data from electroreceptors of paddlefish, which have two distinct types of internal noisy oscillators, one forcing the other. The theory provides an analytical description of their afferent spiking statistics during spontaneous firing, and replicates a pronounced dependence of ISI serial correlation coefficients on the relative frequency of the driving oscillations, and furthermore allows extraction of certain parameters of the intrinsic oscillators embedded in these electroreceptors. PMID:23966844
Bauermeister, Christoph; Schwalger, Tilo; Russell, David F; Neiman, Alexander B; Lindner, Benjamin
2013-01-01
Stochastic signals with pronounced oscillatory components are frequently encountered in neural systems. Input currents to a neuron in the form of stochastic oscillations could be of exogenous origin, e.g. sensory input or synaptic input from a network rhythm. They shape spike firing statistics in a characteristic way, which we explore theoretically in this report. We consider a perfect integrate-and-fire neuron that is stimulated by a constant base current (to drive regular spontaneous firing), along with Gaussian narrow-band noise (a simple example of stochastic oscillations), and a broadband noise. We derive expressions for the nth-order interval distribution, its variance, and the serial correlation coefficients of the interspike intervals (ISIs) and confirm these analytical results by computer simulations. The theory is then applied to experimental data from electroreceptors of paddlefish, which have two distinct types of internal noisy oscillators, one forcing the other. The theory provides an analytical description of their afferent spiking statistics during spontaneous firing, and replicates a pronounced dependence of ISI serial correlation coefficients on the relative frequency of the driving oscillations, and furthermore allows extraction of certain parameters of the intrinsic oscillators embedded in these electroreceptors. PMID:23966844
Shevyrin, Vadim; Melkozerov, Vladimir; Nevero, Alexander; Eltsov, Oleg; Shafran, Yuri; Morzherin, Yuri; Lebedev, Albert T
2015-08-01
Illicit new psychoactive substances (NPS) are a serious threat to health throughout the world. Such NPS do not usually pass preliminary pharmacological trials. In 2014, we identified a series of five new synthetic cannabinoids with an indazole-3-carboxamide structure bearing an N-1-methoxycarbonylalkyl group. The compounds have very high cannabimimetic activity which has caused mass severe intoxication and deaths. The compounds were identified by means of gas chromatography-mass spectrometry (GC-MS), including high-resolution mass spectrometry (GC-HRMS), ultra-high-performance liquid chromatography-high-resolution tandem mass spectrometry (UHPLC-HRMS(2)), and (1)H and (13)C nuclear magnetic resonance spectroscopy (NMR). The peculiarities of mass-spectral fragmentation of the compounds after electron ionization (EI) ionization and collision-induced dissociation (CID) were studied. The analytical characteristics reported for the compounds will enable their identification in a variety of materials seized from criminals.Graphical Abstract. PMID:25893797
2014-01-01
A possibility of the creation of potentiometric biosensor by adsorption of enzyme urease on zeolite was investigated. Several variants of zeolites (nano beta, calcinated nano beta, silicalite, and nano L) were chosen for experiments. The surface of pH-sensitive field-effect transistors was modified with particles of zeolites, and then the enzyme was adsorbed. As a control, we used the method of enzyme immobilization in glutaraldehyde vapour (without zeolites). It was shown that all used zeolites can serve as adsorbents (with different effectiveness). The biosensors obtained by urease adsorption on zeolites were characterized by good analytical parameters (signal reproducibility, linear range, detection limit and the minimal drift factor of a baseline). In this work, it was shown that modification of the surface of pH-sensitive field-effect transistors with zeolites can improve some characteristics of biosensors. PMID:24636423
NASA Astrophysics Data System (ADS)
Shelyakina, Margaryta K.; Soldatkin, Oleksandr O.; Arkhypova, Valentyna M.; Kasap, Berna O.; Akata, Burcu; Dzyadevych, Sergei V.
2014-03-01
A possibility of the creation of potentiometric biosensor by adsorption of enzyme urease on zeolite was investigated. Several variants of zeolites (nano beta, calcinated nano beta, silicalite, and nano L) were chosen for experiments. The surface of pH-sensitive field-effect transistors was modified with particles of zeolites, and then the enzyme was adsorbed. As a control, we used the method of enzyme immobilization in glutaraldehyde vapour (without zeolites). It was shown that all used zeolites can serve as adsorbents (with different effectiveness). The biosensors obtained by urease adsorption on zeolites were characterized by good analytical parameters (signal reproducibility, linear range, detection limit and the minimal drift factor of a baseline). In this work, it was shown that modification of the surface of pH-sensitive field-effect transistors with zeolites can improve some characteristics of biosensors.
Przyjazny, Andrzej; Kokosa, John M
2002-11-22
Headspace solvent microextraction (HSM) is a novel method of sample preparation for chromatographic analysis. It involves exposing a microdrop of high-boiling point organic solvent extruded from the needle tip of a gas chromatographic syringe to the headspace above a sample. Volatile organic compounds are extracted and concentrated in the microdrop. Next, the microdrop is retracted into the microsyringe and injected directly into the chromatograph. HSM has a number of advantages, including renewable drop (no sample carryover), low cost, simplicity and ease of use, short time of analysis, high sensitivity and low detection limits, good precision, minimal solvent use, and no need for instrument modification. This paper presents analytical characteristics of HSM as applied to the determination of benzene, toluene, ethylbenzene and xylenes in water. PMID:12456104
2013-01-01
Background The past decade has witnessed a growing body of research on welfare state characteristics and health inequalities but the picture is, despite this, inconsistent. We aim to review this research by focusing on theoretical and methodological differences between studies that at least in part may lead to these mixed findings. Methods Three reviews and relevant bibliographies were manually explored in order to find studies for the review. Related articles were searched for in PubMed, Web of Science and Google Scholar. Database searches were done in PubMed and Web of Science. The search period was restricted to 2005-01-01 to 2013-02-28. Fifty-four studies met the inclusion criteria. Results Three main approaches to comparative welfare state research are identified; the Regime approach, the Institutional approach, and the Expenditure approach. The Regime approach is the most common and regardless of the empirical regime theory employed and the amendments made to these, results are diverse and contradictory. When stratifying studies according to other features, not much added clarity is achieved. The Institutional approach shows more consistent results; generous policies and benefits seem to be associated with health in a positive way for all people in a population, not only those who are directly affected or targeted. The Expenditure approach finds that social and health spending is associated with increased levels of health and smaller health inequalities in one way or another but the studies are few in numbers making it somewhat difficult to get coherent results. Conclusions Based on earlier reviews and our results we suggest that future research should focus less on welfare regimes and health inequalities and more on a multitude of different types of studies, including larger analyses of social spending and social rights in various policy areas and how these are linked to health in different social strata. But, we also need more detailed evaluation of
Oswald, Tasha M; Beck, Jonathan S; Iosif, Ana-Maria; McCauley, James B; Gilhooly, Leslie J; Matter, John C; Solomon, Marjorie
2016-04-01
Mathematics achievement in autism spectrum disorder (ASD) has been understudied. However, the ability to solve applied math problems is associated with academic achievement, everyday problem-solving abilities, and vocational outcomes. The paucity of research on math achievement in ASD may be partly explained by the widely-held belief that most individuals with ASD are mathematically gifted, despite emerging evidence to the contrary. The purpose of the study was twofold: to assess the relative proportions of youth with ASD who demonstrate giftedness versus disability on applied math problems, and to examine which cognitive (i.e., perceptual reasoning, verbal ability, working memory) and clinical (i.e., test anxiety) characteristics best predict achievement on applied math problems in ASD relative to typically developing peers. Twenty-seven high-functioning adolescents with ASD and 27 age- and Full Scale IQ-matched typically developing controls were assessed on standardized measures of math problem solving, perceptual reasoning, verbal ability, and test anxiety. Results indicated that 22% of the ASD sample evidenced a mathematics learning disability, while only 4% exhibited mathematical giftedness. The parsimonious linear regression model revealed that the strongest predictor of math problem solving was perceptual reasoning, followed by verbal ability and test anxiety, then diagnosis of ASD. These results inform our theories of math ability in ASD and highlight possible targets of intervention for students with ASD struggling with mathematics. PMID:26418313
Identification of dynamic characteristics of flexible rotors as dynamic inverse problem
NASA Technical Reports Server (NTRS)
Roisman, W. P.; Vajingortin, L. D.
1991-01-01
The problem of dynamic and balancing of flexible rotors were considered, which were set and solved as the problem of the identification of flexible rotor systems, which is the same as the inverse problem of the oscillation theory dealing with the task of the identifying the outside influences and system parameters on the basis of the known laws of motion. This approach to the problem allows the disclosure the picture of disbalances throughout the rotor-under-test (which traditional methods of flexible rotor balancing, based on natural oscillations, could not provide), and identify dynamic characteristics of the system, which correspond to a selected mathematical model. Eventually, various methods of balancing were developed depending on the special features of the machines as to their design, technology, and operation specifications. Also, theoretical and practical methods are given for the flexible rotor balancing at far from critical rotation frequencies, which does not necessarily require the knowledge forms of oscillation, dissipation, and elasticity and inertia characteristics, and to use testing masses.
Sleep Characteristics, Sleep Problems, and Associations to Quality of Life among Psychotherapists.
Schlarb, Angelika A; Reis, Dorota; Schröder, Annette
2012-01-01
Sleep problems, especially insomnia, are a common complaint among adults. International studies have shown prevalence rates between 4.7 and 36.2% for sleep difficulties in general, whereas 13.1-28.1% report insomnia symptoms. Sleep problems are associated with lower social and academic performance and can have a severe impact on psychological and physical health. Psychotherapists are suppliers within the public health system. The goal of this study was to outline sleep characteristics, prevalence of sleep problems, insomnia, and associations of quality of life among psychotherapists. A total of 774 psychotherapists (74.7% women; mean age 46 years) participated in the study. Sleep characteristics, sleep problems, well-being, life satisfaction and workload, as well as specific job demands, were assessed via a questionnaire. Analyses revealed that more than 4.2% of the surveyed psychotherapists have difficulties falling asleep, 12.7% often wake up in the night, and 26.6% feel tired, and 3.4% think that their interrupted sleep affects work performance. About 44.1% of them suffer from symptoms of insomnia. Path models showed that insomnia is significantly related to well-being and life satisfaction. PMID:23471477
Building characteristics associated with moisture related problems in 8,918 Swedish dwellings.
Hägerhed-Engman, Linda; Bornehag, Carl-Gustaf; Sundell, Jan
2009-08-01
Moisture problems in buildings have in a number of studies been shown to increase the risk for respiratory symptoms. The study Dampness in Buildings and Health (DBH) was initiated with the aim to identify health relevant exposures related to dampness in buildings. A questionnaire study about home environment with a focus on dampness problems and health was conducted in one county of Sweden (8,918 homes, response rate 79%). Building characteristics that were associated with one or more of the dampness indicators were for single-family houses, older houses, flat-roofed houses built in the 1960s and 1970s, houses with a concrete slab on the ground that were built before 1983. Moreover, tenancy and earlier renovation due to mould or moisture problems was strongly associated with dampness. A perception of dry air was associated with window-pane condensation, e.g. humid indoor air. PMID:19557598
The linearized characteristics method and its application to practical nonlinear supersonic problems
NASA Technical Reports Server (NTRS)
Ferri, Antonio
1952-01-01
The methods of characteristics has been linearized by assuming that the flow field can be represented as a basic flow field determined by nonlinearized methods and a linearized superposed flow field that accounts for small changes of boundary conditions. The method has been applied to two-dimensional rotational flow where the basic flow is potential flow and to axially symmetric problems where conical flows have been used as the basic flows. In both cases the method allows the determination of the flow field to be simplified and the numerical work to be reduced to a few calculations. The calculations of axially symmetric flow can be simplified if tabulated values of some coefficients of the conical flow are obtained. The method has also been applied to slender bodies without symmetry and to some three-dimensional wing problems where two-dimensional flow can be used as the basic flow. Both problems were unsolved before in the approximation of nonlinear flow.
ERIC Educational Resources Information Center
Berg-Nielsen, Turid Suzanne; Solheim, Elisabet; Belsky, Jay; Wichstrom, Lars
2012-01-01
In this study, we explored informant characteristics as determinants of parent-teacher disagreement on preschoolers' psychosocial problems. Teacher characteristics were included in the analyses, in addition to child and parent factors. Psychosocial problems of 732 4-year olds from a Norwegian community sample were assessed by parents and teachers…
Psychosocial problems in patients with newly diagnosed diabetes: number and characteristics.
Rane, K; Wajngot, A; Wändell, P E; Gåfvels, C
2011-09-01
Early in the course of diabetes, it is important to identify and support patients whose psychosocial situations and reactions to the diagnosis may affect their ability to adjust or take adequate responsibility for self-care. We aimed to identify (a) the number and characteristics of patients, 18-65 years, newly diagnosed with diabetes, who needed psychosocial interventions and (b) the type of psychosocial problems they had. A total of 106 patients (72 men) were included in the study. Interviews showed that 41.5% had psychosocial problems. Fifteen dropped out early in the study; 38% of those remaining had psychosocial problems (PSP). More than half had problems with their life situation; most commonly in relationships. About a third had problems related to diabetes, most commonly, work-related. Compared to other participants, PSP patients lived in more strained social situations, especially regarding personal finances and social support. More of the PSP patients were anxious and depressed. They used negative coping strategies more often and more frequently expected that diabetes would negatively affect their future. In conclusion, early in the course of diabetes, screening instruments should be used to identify PSP patients. Treatment by medical social workers skilled in diabetes care should be offered. PMID:21636163
ERIC Educational Resources Information Center
Rubio, Guillermo; del Valle, Rafael
2004-01-01
The study proves that a didactical model based in a method to solve word problems of increasing complexity which uses a numerical approach was essential to develop the analytical ability and the competent use of the algebraic language with students from three different performance levels in elementary algebra. It is shown that before using the…
NASA Astrophysics Data System (ADS)
Dúmet-Montoya, H. S.; Caminha, G. B.; Makler, M.
2013-12-01
Context. The Navarro-Frenk-White (NFW) density profile is often used to model gravitational lenses. For κs ≲ 0.1 (where κs is a parameter that defines the normalization of the NFW lens potential) - corresponding to galaxy and galaxy group mass scales - high numerical precision is required to accurately compute several quantities in the strong lensing regime. Aims: We obtain analytic solutions for several lensing quantities for circular NFW models and their elliptical (ENFW) and pseudo-elliptical (PNFW) extensions, on the typical scales where gravitational arcs are expected to be formed, in the κs ≲ 0.1 limit, by establishing their domain of validity. Methods: We approximate the deflection angle of the circular NFW model and derive analytic expressions for the convergence and shear for the PNFW and ENFW models. We obtain the constant distortion curves (including the tangential critical curve), which are used to define the domain of validity of the approximations, by employing a figure-of-merit to compare with the exact numerical solutions. We compute the deformation cross section as a further check of the validity of the approximations. Results: We derive analytic solutions for iso-convergence contours and constant distortion curves for the models considered here. We also obtain the deformation cross section, which is given in closed form for the circular NFW model and in terms of a one-dimensional integral for the elliptical ones. In addition, we provide a simple expression for the ellipticity of the iso-convergence contours of the pseudo-elliptical models and the connection of characteristic convergences among the PNFW and ENFW models. Conclusions: We conclude that the set of solutions derived here is generally accurate for κs ≲ 0.1. For low ellipticities, values up to κs ≃ 0.18 are allowed. On the other hand, the mapping among PNFW and the ENFW models is valid up to κs ≃ 0.4. The solutions derived in this work can be used to speed up numerical
Sijtsema, J J; Oldehinkel, A J; Veenstra, R; Verhulst, F C; Ormel, J
2014-06-01
Both structural (i.e., SES, familial psychopathology, family composition) and dynamic (i.e., parental warmth and rejection) family characteristics have been associated with aggressive and depressive problem development. However, it is unclear to what extent (changes in) dynamic family characteristics have an independent effect on problem development while accounting for stable family characteristics and comorbid problem development. This issue was addressed by studying problem development in a large community sample (N = 2,230; age 10-20) of adolescents using Linear Mixed models. Paternal and maternal warmth and rejection were assessed via the Egna Minnen Beträffande Uppfostran for Children (EMBU-C). Aggressive and depressive problems were assessed via subscales of the Youth/Adult Self-Report. Results showed that dynamic family characteristics independently affected the development of aggressive problems. Moreover, maternal rejection in preadolescence and increases in paternal rejection were associated with aggressive problems, whereas decreases in maternal rejection were associated with decreases in depressive problems over time. Paternal and maternal warmth in preadolescence was associated with fewer depressive problems during adolescence. Moreover, increases in paternal warmth were associated with fewer depressive problems over time. Aggressive problems were a stable predictor of depressive problems over time. Finally, those who increased in depressive problems became more aggressive during adolescence, whereas those who decreased in depressive problems became also less aggressive. Besides the effect of comorbid problems, problem development is to a large extent due to dynamic family characteristics, and in particular to changes in parental rejection, which leaves much room for parenting-based interventions. PMID:24043499
NASA Astrophysics Data System (ADS)
Alhussan, K.; Morozov, D. O.; Stankevich, Yu. A.; Stanchits, L. K.; Stepanov, K. L.
2014-07-01
The thermal properties of hot air needed for describing the hypersonic motion of bodies in the Earth's atmosphere have been considered. Such motion, as is known, is accompanied by the propagation of strong shock waves analogous to waves generated by powerful explosions. Calculations have been made and data banks have been created for the equations of state and thermal characteristics of air in the temperature and density ranges corresponding to velocities of motion of bodies of up to 10 km/s at altitudes of 0-100 km. The formulation of the problem of hypersonic motion in the absence of thermodynamic equilibrium is discussed.
NASA Technical Reports Server (NTRS)
Lamar, J. E.; Frink, N. T.
1981-01-01
Sixteen analytically and empirically designed strakes have been tested experimentally on a wing-body at three subcritical speeds in such a way as to isolate the strake-forebody loads from the wing-afterbody loads. Analytical estimates for these longitudinal results are made using the suction analogy and the augmented vortex lift concepts. The synergistic data are reasonably well estimated or bracketed by the high- and low-angle-of-attack vortex lift theories over the Mach number range and up to maximum lift or strake-vortex breakdown over the wing. Also, the strake geometry is very important in the maximum lift value generated and the lift efficiency of a given additional area. Increasing size and slenderness ratios are important is generating lift efficiently, but similar efficiency can also be achieved by designing a strake with approximately half the area of the largest gothic strake tested. These results correlate well with strake-vortex-breakdown observations in the water tunnel.
NASA Technical Reports Server (NTRS)
Gorton, C. A.; Lakshminarayana, B.
1980-01-01
The inviscid and viscid effects existing within the passages of a three bladed axial flow inducer operating at a flow coefficient of 0.065 are investigated. The blade static pressure and blade limiting streamline angle distributions were determined and the three components of mean velocity, turbulence intensities, and turbulence stresses were measured at locations inside the inducer blade passage utilizing a rotating three sensor hotwire probe. Applicable equations were derived for the hotwire data reduction analysis and solved numerically to obtain the appropriate flow parameters. The three dimensional inviscid flow in the inducer was predicted by numerically solving the exact equations of motion, and the three dimensional viscid flow was predicted by incorporating the dominant viscous terms into the exact equations. The analytical results are compared with the experimental measurements and design values where appropriate. Radial velocities are found to be of the same order as axial velocities within the inducer passage, confirming the highly three dimensional characteristic of inducer flow. Total relative velocity distribution indicate a substantial velocity deficiency near the tip at mid-passage which expands significantly as the flow proceeds toward the inducer trailing edge. High turbulence intensities and turbulence stresses are concentrated within this core region. Considerable wake diffusion occurs immediately downstream of the inducer trailing edge to decay this loss core. Evidence of boundary layer interactions, blade blockage effects, radially inward flows, annulus wall effects, and backflows are all found to exist within the long, narrow passages of the inducer.
NASA Technical Reports Server (NTRS)
Chin, J. S.; Li, W. M.; Wang, X. F.
1986-01-01
The variation of spray characteristics along a radial distance downstream of a pressure-swirl atomizer was measured by laser light-scattering technology. An analytical model was developed to predict the variation of spray characteristics along the radial distance. A comparison of the predicted and experimental data showed excellent agreement. Therefore, the spray model proposed, although relatively simple, is correct and can be used, with some expansion and modification of the prepared model, to predict more complicated spray systems.
National Helpline for Problem Gambling: A Profile of Its Users' Characteristics
Bastiani, Luca; Fea, Maurizio; Potente, Roberta; Luppi, Claudia; Lucchini, Fabio; Molinaro, Sabrina
2015-01-01
Gambling has seen a significant increase in Italy in the last 10 years and has rapidly become a public health issue, and for these reasons the first National Helpline for Problem Gambling (GR-Helpline) has been established. The aims of this study are to describe the GR-Helpline users' characteristics and to compare the prevalence rates of the users with those of moderate-risk/problematic gamblers obtained from the national survey (IPSAD 2010-2011). Statistical analysis was performed on data obtained from the counselling sessions (phone/e-mail/chat) carried out on 5,805 users (57.5% gamblers; 42.5% families/friends). This confirms that the problems related to gambling concern not only the gamblers but also their families and friends. Significant differences were found between gamblers and families/friends involving gender (74% of gamblers were male; 76.9% of families/friends were female), as well as age-classes and geographical area. Female gamblers had a higher mean age (47.3 versus 40.2 years) and preferred nonstrategy-based games. Prevalence rates of GR-Helpline users and of moderate risk/problematic gamblers were correlated (Rho = 0.58; p = 0.0113). The results highlight the fact that remote access to counselling can be an effective means of promoting treatment for problem gamblers who do not otherwise appeal directly for services. PMID:26064772
Technology Transfer Automated Retrieval System (TEKTRAN)
Maintaining the postharvest quality of fresh-cut fruit after processing and throughout distribution and marketing is a major challenge facing the fresh-cut fruit industry. Analytical quality characteristics of packaged fresh-cut watermelon slices from non-treated and 1-methylcyclopropene (1-MCP)- a...
NASA Astrophysics Data System (ADS)
Courbage, M.
1982-04-01
We study some mathematical problems posed in nonequilibrium statistical mechanics and subdynamics theory developed by Prigogine and coworkers. We study in the superspace of the Hilbert-Schmidt operators the solution of the Liouville-von Neumann equation. The application in this frame of the spectral deformation methods yields expression of analytic continuations of a class of matrix elements of the resolvent of the Liouville-von Neumann operator, and this allows the analytic continuation of the collision and destruction operators. However, it is impossible to obtain simultaneously analytic continuation of the creation operator in this frame. The above results will be used in the second part of the article in order to study the pseudo-Markovian equation.
NASA Astrophysics Data System (ADS)
Song, Qing-Wen; Zhang, Yu-Ming; Zhang, Yi-Men; Lü, Hong-Liang; Chen, Feng-Ping; Zheng, Qing-Li
2009-12-01
A new analytical model for reverse characteristics of 4H-SiC merged PN-Schottky diodes (MPS or JBS) is developed. To accurately calculate the reverse characteristics of the 4H-SiC MPS diode, the relationship between the electric field at the Schottky contact and the reverse bias is analytically established by solving the cylindrical Poisson equation after the channel has pinched off. The reverse current density calculated from the Wentzel-Kramers-Brillouin (WKB) theory is verified by comparing it with the experimental result, showing that they are in good agreement with each other. Moreover, the effects of P-region spacing (S) and P-junction depth (Xj) on the characteristics of 4H-SiC MPS are analysed, and are particularly useful for optimizing the design of the high voltage MPS diodes.
NASA Astrophysics Data System (ADS)
Yang, Gang; Tang, Zheng; Dai, Hongwei
Through analyzing the dynamics characteristic of maximum neural network with an added vertex, we find that the solution quality is mainly determined by the added vertex weights. In order to increase maximum neural network ability, a stochastic nonlinear self-feedback and flexible annealing strategy are embedded in maximum neural network, which makes the network more powerful to escape local minima and be independent of the initial values. Simultaneously, we present that solving ability of maximum neural network is dependence on problem. We introduce a new parameter into our network to improve the solving ability. The simulation in k random graph and some DIMACS clique instances in the second DIMACS challenge shows that our improved network is superior to other algorithms in light of the solution quality and CPU time.
Johnson, Cynthia R; Turner, Kylan; Stewart, Patricia A; Schmidt, Brianne; Shui, Amy; Macklin, Eric; Reynolds, Anne; James, Jill; Johnson, Susan L; Manning Courtney, Patty; Hyman, Susan L
2014-09-01
Many children with autism spectrum disorders (ASD) have co-occurring feeding problems. However, there is limited knowledge about how these feeding habits are related to other behavioral characteristics ubiqitious in ASD. In a relatively large sample of 256 children with ASD, ages 2-11, we examined the relationships between feeding and mealtime behaviors and social, communication, and cognitive levels as well repetitive and ritualistic behaviors, sensory behaviors, and externalizing and internalizing behaviors. Finally, we examined whether feeding habits were predictive of nutritional adequacy. In this sample, we found strong associations between parent reported feeding habits and (1) repetitive and ritualistic behaviors, (2) sensory features, and (3) externalizing and internalizing behavior. There was a lack of association between feeding behaviors and the social and communication deficits of ASD and cognitive levels. Increases in the degree of problematic feeding behaviors predicted decrements in nutritional adequacy. PMID:24664635
NASA Technical Reports Server (NTRS)
Hong, D. C.; Langer, J. S.
1986-01-01
An analytic approach to the problem of predicting the widths of fingers in a Hele-Shaw cell is presented. The analysis is based on the WKB technique developed recently for dealing with the effects of surface tension in the problem of dendritic solidification. It is found that the relation between the dimensionless width lambda and the dimensionless group of parameters containing the surface tension, nu, has the form lambda - 1/2 = nu exp 2/3 in the limit of small nu.
ERIC Educational Resources Information Center
Oshiro, Claudia Kami Bastos; Kanter, Jonathan; Meyer, Sonia Beatriz
2012-01-01
Functional Analytic Psychotherapy (FAP) is emerging as an effective psychotherapy for psychiatric clinical cases. However, there is little research demonstrating the process of change of FAP. The present study evaluated the introduction and withdrawal of FAP interventions on therapy-interfering verbal behaviors of two participants who were in…
ERIC Educational Resources Information Center
Baker, Amy J. L.; Archer, Marc; Curtis, Patrick
2007-01-01
This study aimed to determine what youth characteristics were associated with emotional and behavioral problems exhibited within the first three months of placement in residential treatment centers (RTCs) in a sample of youth from 20 agencies in 13 states. Two primary research questions were addressed: 1) What characteristics were associated with…
Pesin, Yakov B.; Niu, Xun; Latash, Mark L.
2010-01-01
We consider the problem of what is being optimized in human actions with respect to various aspects of human movements and different motor tasks. From the mathematical point of view this problem consists of finding an unknown objective function given the values at which it reaches its minimum. This problem is called the inverse optimization problem. Until now the main approach to this problems has been the cut-and-try method, which consists of introducing an objective function and checking how it reflects the experimental data. Using this approach, different objective functions have been proposed for the same motor action. In the current paper we focus on inverse optimization problems with additive objective functions and linear constraints. Such problems are typical in human movement science. The problem of muscle (or finger) force sharing is an example. For such problems we obtain sufficient conditions for uniqueness and propose a method for determining the objective functions. To illustrate our method we analyze the problem of force sharing among the fingers in a grasping task. We estimate the objective function from the experimental data and show that it can predict the force-sharing pattern for a vast range of external forces and torques applied to the grasped object. The resulting objective function is quadratic with essentially non-zero linear terms. PMID:19902213
ERIC Educational Resources Information Center
Patkin, Dorit; Gazit, Avikam
2011-01-01
This article aims to present the findings of a research which investigated the effect of a difference in word formulation and mathematical characteristics of story problems on their successful solution by preservice mathematics teachers (students) and practising mathematics teachers. The findings show that in the case of a problem with a…
NASA Astrophysics Data System (ADS)
Knosowski, Yvonne; von Lieres, Eric; Schneider, Adrian
1999-06-01
In this paper we consider the non-characteristic Cauchy problem 0266-5611/15/3/307/img1" ALT="(equation)"/> where 0266-5611/15/3/307/img2" ALT="(equation)"/> with appropriate coefficient functions a, b and c. Assuming that the Cauchy data icons/Journals/Common/varphi" ALT="varphi are given inexactly by a function icons/Journals/Common/varphi" ALT="varphiicons/Journals/Common/varepsilon" ALT="varepsilon" ALIGN="MIDDLE"/> satisfying ||icons/Journals/Common/varphi" ALT="varphi" ALIGN="TOP"/>-icons/Journals/Common/varphi" ALT="varphi" ALIGN="TOP"/>icons/Journals/Common/varepsilon" ALT="varepsilon" ALIGN="MIDDLE"/>||Hricons/Journals/Common/le" ALT="le" ALIGN="TOP"/> icons/Journals/Common/varepsilon" ALT="varepsilon" ALIGN="TOP"/> for some ricons/Journals/Common/le" ALT="le" ALIGN="TOP"/>0 and that f(y,t): = u(l,y,t) exists and belongs to Hs(icons/Journals/Common/BbbR" ALT="BbbR" ALIGN="TOP"/>n-1 × icons/Journals/Common/BbbR" ALT="BbbR" ALIGN="TOP"/>) for some sicons/Journals/Common/in" ALT="in" ALIGN="TOP"/>icons/Journals/Common/BbbR" ALT="BbbR" ALIGN="TOP"/>, it is desired to calculate f from the improper data icons/Journals/Common/varphi" ALT="varphi" ALIGN="TOP"/>icons/Journals/Common/varepsilon" ALT="varepsilon" ALIGN="MIDDLE"/>. This problem is well known to be severely ill-posed: a small perturbation in the Cauchy data may cause a dramatically large error in the solution. In this paper the following mollification method is suggested for this problem: if the Cauchy data are given inexactly then we mollify them by projection on elements of Meyers multiresolution approximation {Vj}jicons/Journals/Common/in" ALT="in" ALIGN="TOP"/>icons/Journals/Common/BbbZ" ALT="BbbZ" ALIGN="TOP"/>. Within every space Vj the solution of the above problem depends continuously on the data, and we can find a mollification parameter J depending on the noise level icons/Journals/Common/varepsilon" ALT="varepsilon" ALIGN="TOP"/> in the Cauchy data such that the error estimation between the
NASA Astrophysics Data System (ADS)
Butt, N.; Pidlisecky, A.; Ganshorn, H.; Cockett, R.
2015-12-01
The software company 3 Point Science has developed three interactive learning programs designed to teach, test and practice visualization skills and geoscience concepts. A study was conducted with 21 geoscience students at the University of Calgary who participated in 2 hour sessions of software interaction and written pre and post-tests. Computer and SMART touch table interfaces were used to analyze user interaction, problem solving methods and visualization skills. By understanding and pinpointing user problem solving methods it is possible to reconstruct viewpoints and thought processes. This could allow us to give personalized feedback in real time, informing the user of problem solving tips and possible misconceptions.
Bifocal contact lenses: History, types, characteristics, and actual state and problems
Toshida, Hiroshi; Takahashi, Kozo; Sado, Kazushige; Kanai, Atsushi; Murakami, Akira
2008-01-01
Since people who wear contact lenses (CL) often continue using CL even when they develop presbyopia, there are growing expectations for bifocal CL. To understand actual state and problems, history, types, and their characteristics are summarized in this review. Bifocal CL have a long history over 70 years. Recently, bifocal CL have achieved remarkable progress. However, there still is an impression that prescription of bifocal CL is not easy. It should also be remembered that bifocal CL have limits, including limited addition for near vision, as well as the effects of aging and eye diseases in the aged, such as dry eye, astigmatism, cataract, etc. Analysis of the long-term users of bifocal CL among our patients has revealed the disappearance of bifocal CL that achieved unsatisfactory vision and poor contrast compared with those provided by other types of CL. Changing the prescription up to 3 times for lenses of the same brand may be appropriate. Lenses that provide poor contrast sensitivity, suffer from glare, or give unsatisfactory vision have been weeded out. The repeated replacement of products due to the emergence of improved or new products will be guessed. PMID:19668441
Tsai, Y.M.; Crane, R.A. )
1992-05-01
Heat transfer across surfaces in imperfect contact occurs in many practical situations. Since the thermal contact conductance problem has appeared in the literature, substantial efforts have been made to estimate the thermal conductance across the interface. Some of the techniques recently developed of estimating thermal contact conductance are based on experimental temperature data at one or several interior positions of the contacting solids and the calculation of the temperature at these locations for known contact conductance. Consequently, an accurate and efficient method for computing temperature distributions because quite important. FDM and FEM are most widely used. However, for most contact conductance computation methods, only the temperatures at the contacting regions and several other positions near the interface need to be determined, so the general FDM and FEM are not particularly efficient in solving this problem. This paper presents an analytical temperature distribution solution to the one-dimensional symmetric system with heat flux on one outside surface and insulation on the other. This analysis provides a theoretical basis for transient measurement of thermal contact conductance. While it is common practice in steady-state measurements to use a water-cooled heat sink, it is possible to limit the transient solution to time interval prior to any detectable temperature increase at the cold end. This effectively eliminates the need for water cooling and permits the use of an insulated boundary. The analytical solution to the mentioned problem obtained shows that for a symmetric system the temperature distribution solution includes two sets of distinct eigenfunctions.
Lorenz, Ralph D
2012-08-01
Thermal drilling has been applied to studies of glaciers on Earth and proposed for study of the martian ice caps and the crust of Europa. Additionally, inadvertent thermal drilling by radioisotope sources released from the breakup of a space vehicle is of astrobiological concern in that this process may form a downward-propagating "warm little pond" that could convey terrestrial biota to a habitable environment. A simple analytic solution to the asymptotic slow-speed case of thermal drilling is noted and used to show that the high thermal conductivity of the low-temperature ice on Europa and Titan makes thermal drilling qualitatively more difficult than at Mars. It is shown that an isolated General Purpose Heat Source (GPHS) "brick" can drill effectively on Earth or Mars, whereas on Titan or Europa with ice at 100 K, the source would stall and become stuck in the ice with a surface temperature of <200 K. PMID:22897131
A Meta-Analytic and Qualitative Review of Online versus Face-to-Face Problem-Based Learning
ERIC Educational Resources Information Center
Jurewitsch, Brian
2012-01-01
Problem-based learning (PBL) is an instructional strategy that is poised for widespread application in the current, growing, on-line digital learning environment. While enjoying a track record as a defensible strategy in face-to-face learning settings, the research evidence is not clear regarding PBL in on-line environments. A review of the…
ERIC Educational Resources Information Center
Ghoneim, Nahed Mohamed Mahmoud
2013-01-01
The current study focused on the problems which students encounter while listening to the English language, the mental processes they activate in listening comprehension, and the strategies they use in different phases of comprehension. Also, it aimed to find out whether there were any differences between advanced and intermediate students in…
ERIC Educational Resources Information Center
Thorsland, Martin Nils
The purposes of this study were: (1) to evaluate the effectiveness of audio-tutorial (A-T) instruction and (2) to identify, classify and study differences in problem solving approach using a theoretical framework derived from the ideas of D. P. Ausubel. Seventy of 420 students taking a college introductory non-calculus physics course used A-T…
NASA Astrophysics Data System (ADS)
Bashiri, Mahdi; Karimi, Hossein
2012-07-01
Quadratic assignment problem (QAP) is a well-known problem in the facility location and layout. It belongs to the NP-complete class. There are many heuristic and meta-heuristic methods, which are presented for QAP in the literature. In this paper, we applied 2-opt, greedy 2-opt, 3-opt, greedy 3-opt, and VNZ as heuristic methods and tabu search (TS), simulated annealing, and particle swarm optimization as meta-heuristic methods for the QAP. This research is dedicated to compare the relative percentage deviation of these solution qualities from the best known solution which is introduced in QAPLIB. Furthermore, a tuning method is applied for meta-heuristic parameters. Results indicate that TS is the best in 31%of QAPs, and the IFLS method, which is in the literature, is the best in 58 % of QAPs; these two methods are the same in 11 % of test problems. Also, TS has a better computational time among heuristic and meta-heuristic methods.
Bereketli Zafeirakopoulos, Ilke Erol Genevois, Mujde
2015-09-15
Life Cycle Assessment is a tool to assess, in a systematic way, the environmental aspects and its potential environmental impacts and resources used throughout a product's life cycle. It is widely accepted and considered as one of the most powerful tools to support decision-making processes used in ecodesign and sustainable production in order to learn about the most problematic parts and life cycle phases of a product and to have a projection for future improvements. However, since Life Cycle Assessment is a cost and time intensive method, companies do not intend to carry out a full version of it, except for large corporate ones. Especially for small and medium sized enterprises, which do not have enough budget for and knowledge on sustainable production and ecodesign approaches, focusing only on the most important possible environmental aspect is unavoidable. In this direction, finding the right environmental aspect to work on is crucial for the companies. In this study, a multi-criteria decision-making methodology, Analytic Network Process is proposed to select the most relevant environmental aspect. The proposed methodology aims at providing a simplified environmental assessment to producers. It is applied for a hand blender, which is a member of the Electrical and Electronic Equipment family. The decision criteria for the environmental aspects and relations of dependence are defined. The evaluation is made by the Analytic Network Process in order to create a realistic approach to inter-dependencies among the criteria. The results are computed via the Super Decisions software. Finally, it is observed that the procedure is completed in less time, with less data, with less cost and in a less subjective way than conventional approaches. - Highlights: • We present a simplified environmental assessment methodology to support LCA. • ANP is proposed to select the most relevant environmental aspect. • ANP deals well with the interdependencies between aspects and
Not Available
2006-06-01
In the Analytical Microscopy group, within the National Center for Photovoltaic's Measurements and Characterization Division, we combine two complementary areas of analytical microscopy--electron microscopy and proximal-probe techniques--and use a variety of state-of-the-art imaging and analytical tools. We also design and build custom instrumentation and develop novel techniques that provide unique capabilities for studying materials and devices. In our work, we collaborate with you to solve materials- and device-related R&D problems. This sheet summarizes the uses and features of four major tools: transmission electron microscopy, scanning electron microscopy, the dual-beam focused-ion-beam workstation, and scanning probe microscopy.
Behaviour-Emotional Characteristics of Primary-School Children Rated as Having Language Problems
ERIC Educational Resources Information Center
Lundervold, A. J.; Heimann, M.; Manger, T.
2008-01-01
Background: Primary-school teachers are expected to detect problems related to language function, but the teachers' evaluations may be heavily influenced by gender and classroom behaviour. Aim: To investigate the relationship between language problems (LPs) and behaviour-emotional problems as rated by primary-school teachers. Methods: All…
NASA Astrophysics Data System (ADS)
Xiong, Jianyin; Liu, Cong; Zhang, Yinping
2012-02-01
A general analytical model for characterizing emission and sorption of formaldehyde and volatile organic compounds (VOCs) in single-layer building materials is developed. Compared with traditional models, the present model can be applicable for four kinds of typical physical processes, i.e., emission in ventilated and airtight chambers, and sorption in these two types of chambers. Based on the general analytical model, a novel method is proposed to determine the characteristic parameters (the diffusion coefficient, Dm, and the material/air partition coefficient, K) of formaldehyde and VOC sorption in ventilated and airtight chambers. It establishes a linear relationship between the logarithm of dimensionless excess concentration and sorption time, and the Dm and K can be conveniently obtained from the slope and intercept of the regression line. The results of applying the present model are compared with the experimental data in the literature. The good agreement between them not only validates the model but also demonstrates that the measured characteristic parameters are accurate and reliable. The general analytical model should prove useful for unified characterization and prediction of emission/sorption in building materials as well as for parameter measurement.
NASA Technical Reports Server (NTRS)
Gorton, C. A.; Lakshminarayana, B.
1974-01-01
The effort conducted to gather additional understanding of the complex inviscid and viscid effects existing within the passages of a three-bladed axial flow inducer operating at a flow coefficient of 0.065 is summarized. The experimental investigations included determination of the blade static pressure and blade limiting streamline angle distributions, and measurement of the three components of mean velocity, turbulence intensities and turbulence stresses at locations inside the inducer blade passage utilizing a rotating three-sensor hotwire probe. Applicable equations were derived for the hotwire data reduction analysis and solved numerically to obtain the appropriate flow parameters. Analytical investigations were conducted to predict the three-dimensional inviscid flow in the inducer by numerically solving the exact equations of motion, and to approximately predict the three-dimensional viscid flow by incorporating the dominant viscous terms into the exact equations. The analytical results are compared with the experimental measurements and design values where appropriate.
NASA Technical Reports Server (NTRS)
Longuski, James M.; Mcronald, Angus D.
1988-01-01
In previous work the problem of injecting the Galileo and Ulysses spacecraft from low earth orbit into their respective interplanetary trajectories has been discussed for the single stage (Centaur) vehicle. The central issue, in the event of spherically distributed injection errors, is what happens to the vehicle? The difficulties addressed in this paper involve the multi-stage problem since both Galileo and Ulysses will be utilizing the two-stage IUS system. Ulysses will also include a third stage: the PAM-S. The solution is expressed in terms of probabilities for total percentage of escape, orbit decay and reentry trajectories. Analytic solutions are found for Hill's Equations of Relative Motion (more recently called Clohessy-Wiltshire Equations) for multi-stage injections. These solutions are interpreted geometrically on the injection sphere. The analytic-geometric models compare well with numerical solutions, provide insight into the behavior of trajectories mapped on the injection sphere and simplify the numerical two-dimensional search for trajectory families.
ERIC Educational Resources Information Center
Farmer, Thomas W.; Goforth, Jennifer B.; Clemmer, Jason T.; Thompson, Jana H.
2004-01-01
The authors examined school discipline problems in relation to academic and interpersonal characteristics of students in a middle school of a rural low-income community. The sample comprised 259 students (83 boys, 176 girls)--all of whom were African American--and reflected the community's public school attendance. School records were examined,…
ERIC Educational Resources Information Center
Lecavalier, Luc
2006-01-01
Parents or teachers rated 487 non-clinically referred young people with Pervasive Developmental Disorders on the Nisonger Child Behavior Rating Form. The objectives of the study were to examine the relative prevalence of specific behavior problems, assess the impact of subject characteristics, and derive an empirical classification of behavioral…
ERIC Educational Resources Information Center
Ozgen, Kemal; Alkan, Huseyin
2012-01-01
The present study examined the potential relationship between 1st and 5th year secondary school pre-service mathematics teachers' skills in understanding, method, modelling, verification, and extension dimensions of problem solving and their learning style characteristics. The data consisted of the skills pre-service teachers demonstrated in the…
NASA Technical Reports Server (NTRS)
Sutliff, Daniel L.; Walker, Bruce E.
2014-01-01
An Ultrasonic Configurable Fan Artificial Noise Source (UCFANS) was designed, built, and tested in support of the NASA Langley Research Center's 14x22 wind tunnel test of the Hybrid Wing Body (HWB) full 3-D 5.8% scale model. The UCFANS is a 5.8% rapid prototype scale model of a high-bypass turbofan engine that can generate the tonal signature of proposed engines using artificial sources (no flow). The purpose of the program was to provide an estimate of the acoustic shielding benefits possible from mounting an engine on the upper surface of a wing; a flat plate model was used as the shielding surface. Simple analytical simulations were used to preview the radiation patterns - Fresnel knife-edge diffraction was coupled with a dense phased array of point sources to compute shielded and unshielded sound pressure distributions for potential test geometries and excitation modes. Contour plots of sound pressure levels, and integrated power levels, from nacelle alone and shielded configurations for both the experimental measurements and the analytical predictions are presented in this paper.
Against All Odds: Problem-Solving Strategies and Behavioural Characteristics of Novice Students
ERIC Educational Resources Information Center
Chang, Pei-Fen; Lin, Miao-Chen
2015-01-01
This study investigates problem-solving difficulties of novices in a classroom setting, using a German instructional tool, the Fischertechnik kit of approximately 400 parts. In order to analyse the students' thinking processes as they solved the problems, verbal protocol analysis (VPA) was used to record the students'' thinking…
Characteristics of a Cognitive Tool That Helps Students Learn Diagnostic Problem Solving
ERIC Educational Resources Information Center
Danielson, Jared A.; Mills, Eric M.; Vermeer, Pamela J.; Preast, Vanessa A.; Young, Karen M.; Christopher, Mary M.; George, Jeanne W.; Wood, R. Darren; Bender, Holly S.
2007-01-01
Three related studies replicated and extended previous work (J.A. Danielson et al. (2003), "Educational Technology Research and Development," 51(3), 63-81) involving the Diagnostic Pathfinder (dP) (previously Problem List Generator [PLG]), a cognitive tool for learning diagnostic problem solving. In studies 1 and 2, groups of 126 and 113…
ERIC Educational Resources Information Center
Matson, Johnny L.; Horovitz, Max; Sipes, Megan
2011-01-01
The prevalence of toileting problems was assessed in 153 adults with intellectual disability (ID) using the "Profile of Toileting Issues" ("POTI") and comparisons were made based on various demographic variables. The most frequently endorsed problems were "has toileting accidents during the day," "has toileting accidents during the night," "has…
Technology Transfer Automated Retrieval System (TEKTRAN)
A novel hybrid muskmelon has been bred specifically for use by the fresh-cut industry in winter. Quality characteristics of fresh-cut chunks from the hybrid were compared to those of its inbred parental lines and to those of a commercial netted muskmelon (cantaloupe) and a non-netted muskmelon (hon...
NASA Technical Reports Server (NTRS)
Thompson, W. C.; Boghani, A. B.; Leland, T. J. W.
1977-01-01
An investigation was conducted to compare the steady-state and dynamic flow characteristics of an axial-flow fan which had been used previously as the air supply fan for some model air cushion landing system studies. Steady-state flow characteristics were determined in the standard manner by using differential orifice pressures for the flow regime from free flow to zero flow. In this same regime, a correlative technique was established so that fan inlet and outlet pressures could be used to measure dynamic flow as created by a rotating damper. Dynamic tests at damper frequencies up to 5 Hz showed very different flow characteristics when compared with steady-state flow, particularly with respect to peak pressures and the pressure-flow relationship at fan stall and unstall. A generalized, rational mathematical fan model was developed based on physical fan parameters and a steady-state flow characteristic. The model showed good correlation with experimental tests at damper frequencies up to 5 Hz.
NASA Technical Reports Server (NTRS)
Graham, A. B.
1977-01-01
Small- and large-scale models of supersonic cruise fighter vehicles were used to determine the effectiveness of airframe/propulsion integration concepts for improved low-speed performance and stability and control characteristics. Computer programs were used for engine/airframe sizing studies to yield optimum vehicle performance.
NASA Technical Reports Server (NTRS)
Murphy, A. C.
1981-01-01
Experimental data and correlative analytical results on the flutter and gust response characteristics of a torsion-free-wing (TFW) fighter airplane model are presented. TFW consists of a combined wing/boom/canard surface and was tested with the TFW free to pivot in pitch and with the TFW locked to the fuselage. Flutter and gust response characteristics were measured in the Langley Transonic Dynamics Tunnel with the complete airplane model mounted on a cable mount system that provided a near free flying condition. Although the lowest flutter dynamic pressure was measured for the wing free configuration, it was only about 20 deg less than that for the wing locked configuration. However, no appreciable alleviation of the gust response was measured by freeing the wing.
Jaffee, Sara R.
2010-01-01
Objective The first objective of this study was to test for sex differences in four childhood sexual abuse characteristics---penetration, substantiation, perpetrator familial status, and multi-maltreatment---in a national sample of youth. The second objective was to test for sex differences in how these abuse characteristics were associated with victims’ emotional and behavioral problems. Methods The sample was drawn from the National Survey of Child and Adolescent Well-Being, a sample of children investigated by United States child welfare services. Youth in the current study (n = 573, including 234 adolescents) were investigated for alleged sexual abuse. Logistic regression and multivariate analysis of covariance were used to test for sex differences in abuse characteristics, and to determine whether sex moderated associations between abuse characteristics and emotional and behavioral problems. Results Girls were more likely than boys to have their abuse substantiated and to experience penetrative abuse (although differences in penetration status did not emerge among adolescents). Substantiation status and child age were positively associated with caregiver-reported internalizing and externalizing symptoms. Sex did not moderate the relationship between abuse characteristics and youth emotional and behavioral problems. Conclusions Sexual abuse characteristics might not be highly predictive factors when making decisions about services needs. Furthermore, there may not be a strong empirical basis for operating on the assumption that one sex is more vulnerable to negative consequences of abuse than the other, or that abuse affects girls and boys differently. The processes explaining why some victims exhibit more impairment than others are likely complex. PMID:20400178
NASA Astrophysics Data System (ADS)
Blokhintsev, L. D.; Nikitina, L. I.; Orlov, Yu. V.; Savin, D. A.
2014-08-01
In the present work one- and two-channel approaches using the expansion of the effective-range function K( E) in powers of energy E are applied to obtain the asymptotic normalization coefficients (ANCs) and vertex constants (VCs) for the d + α system. The coefficients of the K( E) expansion are found by fitting the d α phase shifts. By analytic continuation of K( E) thus obtained to the corresponding poles the ANCs and VCs for D wave d α resonances with J π = 1+, 2+, 3+ are calculated for the first time. The 1+-resonance and the bound state of 6Li ( J π = 1+) are considered jointly in the two-channel ( S + D) effective-range approach and the ANCs and VCs for the ground 6Li state are found.
Tyteca, Eva; Desmet, Gert
2015-07-17
Some valuable insights have been obtained in the inherent fitting problems when trying to predict the retention time of complex, multi-modal retention modes such as encountered in HILIC and SFC. In this study, we used mathematical models with known input parameters to generate different sets of numerical test curves representative for systems exhibiting a complex, non-LSS dual retention behavior. Subsequently, we tried to fit these data sets using some popular (non-linear) literature models. Even in cases where a physical fitting model exists (e.g., the mixed model in case of pure additive adsorptive and partitioning retention), the fitting quality can only be expected to be relatively good (prediction errors expressed in terms of a normalized resolution error ɛRs) when carefully selecting the scouting runs and the appropriate starting values for the fitting algorithm. The latter can best be done using a comprehensive grid search scanning a wide range of different starting values. This becomes even more important when no good physical model is available and one has to use a non-physical fitting model, such as the empirical Neue-model. The use of higher-order models is found to be quasi indispensable to keep the prediction errors on the order of some ΔRs=0.05. Also, the choice of the scouting runs becomes even more important using these higher-order models. For highly retained compounds we recommend using scouting runs with long tG/t0-values or to include a run with a higher fraction of eluting solvent at the start of the gradient. When trying to predict gradient retention, errors with which the isocratic retention behavior is fitted are much less important for high retention factors k than errors made in the range of k near the one at the point of elution. The results obtained with a so-called segmented Neue-model (containing 7 parameters) were less good and thus practically not interesting (because of the high number of initial runs). PMID:26044381
Russell, G.A.
1991-06-01
Electromagnetic Interference (EMI) problems have resulted in the redesign of the SANDAC V computer case and shielding of its connecting cables. In this report are detailed discussions on the use of computer models and of the tests performed to solve the EMI problems. Included is documentation on the specific changes made to the SANDAC V computer case and the shielding done on the connecting cables. Also documented are the current EMI capabilities relative to MIL Std. 461.
Cierniak, Robert; Lorent, Anna
2016-09-01
The main aim of this paper is to investigate properties of our originally formulated statistical model-based iterative approach applied to the image reconstruction from projections problem which are related to its conditioning, and, in this manner, to prove a superiority of this approach over ones recently used by other authors. The reconstruction algorithm based on this conception uses a maximum likelihood estimation with an objective adjusted to the probability distribution of measured signals obtained from an X-ray computed tomography system with parallel beam geometry. The analysis and experimental results presented here show that our analytical approach outperforms the referential algebraic methodology which is explored widely in the literature and exploited in various commercial implementations. PMID:27289536
Chahine, G.L.; Genoux, P.F.; Johnson, V.E. Jr.; Frederick, G.S.
1984-09-01
Waterjet nozzles (STRATOJETS) have been developed which achieve passive structuring of cavitating submerged jets into discrete ring vortices, and which possess cavitation incipient numbers six times higher than obtained with conventional cavitating jet nozzles. In this study we developed analytical and numerical techniques and conducted experimental work to gain an understanding of the basic phenomena involved. The achievements are: (1) a thorough analysis of the acoustic dynamics of the feed pipe to the nozzle; (2) a theory for bubble ring growth and collapse; (3) a numerical model for jet simulation; (4) an experimental observation and analysis of candidate second-generation low-sigma STRATOJETS. From this study we can conclude that intensification of bubble ring collapse and design of highly resonant feed tubes can lead to improved drilling rates. The models here described are excellent tools to analyze the various parameters needed for STRATOJET optimizations. Further analysis is needed to introduce such important factors as viscosity, nozzle-jet interaction, and ring-target interaction, and to develop the jet simulation model to describe the important fine details of the flow field at the nozzle exit.
Learning-Method Choices and Personal Characteristics in Solving a Physical Education Problem
ERIC Educational Resources Information Center
Vincent-Morin, Madeleine; Lafont, Lucile
2005-01-01
The goal of this study was to identify the relationships between the learning choices made by pupils and their personal characteristics, including cognitive style (field dependence--independence), a motivational variable (feeling of self-efficacy), and a cognitive variable (task representation). The participants were 64 twelve-year-old sixth…
ERIC Educational Resources Information Center
Flessner, Christopher A.; Woods, Douglas W.
2006-01-01
In this study, the authors collected data on the demographic characteristics, phenomenology, and social and economic impact of skin picking. A total of 92 participants completed an anonymous, Internet-based survey through a link to the Trichotillomania Learning Center's home page. Results indicated that skin pickers experienced social,…
ERIC Educational Resources Information Center
Barry, Adam E.; Misra, Ranjita; Dennis, Maurice
2006-01-01
Driving a vehicle under the influence of alcohol is a major public health concern. By distinguishing the type of individuals violating driving while intoxicated (DWI) sanctions, intervention programs will be better suited to reduce drinking and driving. The purpose of this study was to examine the personal characteristics of DWI offenders and…
ERIC Educational Resources Information Center
Gaudiano, Brandon A.; Brown, Lily A.; Miller, Ivan W.
2012-01-01
Objective: The objective was to learn about the characteristics of psychotherapists who use energy meridian techniques (EMTs). Methods: We conducted an Internet-based survey of the practices and attitudes of licensed psychotherapists. Results: Of 149 survey respondents (21.4% social workers), 42.3% reported that they frequently use or are inclined…
ERIC Educational Resources Information Center
Khan, Anwar; Yusoff, Rosman Bin Md; Isa, Khairunesa Binti
2016-01-01
Scholarly work and research are globally known as stressful and challenging. Teachers may develop different psychological health problems once they are exposed to workplace stressors. Considering it as a serious issue of education sector, this study has examined the linkages between prevalent workplace stressors and psychological health problems…
ERIC Educational Resources Information Center
Mergendoller, John R.; Maxwell, Nan L.; Bellisimo, Yolanda
2006-01-01
This study compared the effectiveness of problem-based learning (PBL) and traditional instructional approaches in developing high-school students' macroeconomics knowledge and examined whether PBL was differentially effective with students demonstrating different levels of four aptitudes: verbal ability, interest in economics, preference for group…
ERIC Educational Resources Information Center
Nitschke, Kai; Ruh, Nina; Kappler, Sonja; Stahl, Christoph; Kaller, Christoph P.
2012-01-01
Understanding the functional neuroanatomy of planning and problem solving may substantially benefit from better insight into the chronology of the cognitive processes involved. Based on the assumption that regularities in cognitive processing are reflected in overtly observable eye-movement patterns, here we recorded eye movements while…
Costs of the New Information Technologies in Education: Characteristics and Problems of Measurement.
ERIC Educational Resources Information Center
Eicher, J. C.
Although an increasing number of theoretical analyses and evaluations have been conducted since microcomputer technology was developed and introduced into classrooms, few new studies have been undertaken on the costs of these new information technologies (NIT). This report focuses on the methodological problems that must be solved in order to…
Some Characteristics and Personality Problems of Children Who Are Victims of Child Abuse.
ERIC Educational Resources Information Center
Hildreth, Gladys J.; And Others
This paper explores the concept of child abuse. The analysis begins by explaining the problems evident in defining child abuse, and presents the historical development of child abuse prevention. A theoretical discussion on personality development is also included. The second section of the paper describes results of a research project designed to…
Holzhauser, Thomas; Ree, Ronald van; Poulsen, Lars K; Bannon, Gary A
2008-10-01
There is detailed guidance on how to perform bioinformatic analyses and enzymatic degradation studies for genetically modified crops under consideration for approval by regulatory agencies; however, there is no consensus in the scientific community on the details of how to perform IgE serum studies. IgE serum studies are an important safety component to acceptance of genetically modified crops when the introduced protein is novel, the introduced protein is similar to known allergens, or the crop is allergenic. In this manuscript, we describe the characteristics of the reagents, validation of assay performance, and data analysis necessary to optimize the information obtained from serum testing of novel proteins and genetically modified (GM) crops and to make results more accurate and comparable between different investigations. PMID:18727951
NASA Astrophysics Data System (ADS)
Velychko, T. P.; Soldatkin, O. O.; Melnyk, V. G.; Marchenko, S. V.; Kirdeciler, S. K.; Akata, B.; Soldatkin, A. P.; El'skaya, A. V.; Dzyadevych, S. V.
2016-02-01
Development of a conductometric biosensor for the urea detection has been reported. It was created using a non-typical method of the recombinant urease immobilization via adsorption on nanoporous particles of silicalite. It should be noted that this biosensor has a number of advantages, such as simple and fast performance, the absence of toxic compounds during biosensor preparation, and high reproducibility (RSD = 5.1 %). The linear range of urea determination by using the biosensor was 0.05-15 mM, and a lower limit of urea detection was 20 μM. The bioselective element was found to be stable for 19 days. The characteristics of recombinant urease-based biomembranes, such as dependence of responses on the protein and ion concentrations, were investigated. It is shown that the developed biosensor can be successfully used for the urea analysis during renal dialysis.
Velychko, T P; Soldatkin, О О; Melnyk, V G; Marchenko, S V; Kirdeciler, S K; Akata, B; Soldatkin, A P; El'skaya, A V; Dzyadevych, S V
2016-12-01
Development of a conductometric biosensor for the urea detection has been reported. It was created using a non-typical method of the recombinant urease immobilization via adsorption on nanoporous particles of silicalite. It should be noted that this biosensor has a number of advantages, such as simple and fast performance, the absence of toxic compounds during biosensor preparation, and high reproducibility (RSD = 5.1 %). The linear range of urea determination by using the biosensor was 0.05-15 mM, and a lower limit of urea detection was 20 μM. The bioselective element was found to be stable for 19 days. The characteristics of recombinant urease-based biomembranes, such as dependence of responses on the protein and ion concentrations, were investigated. It is shown that the developed biosensor can be successfully used for the urea analysis during renal dialysis. PMID:26911570
Hoffman, A. J.; Lee, J. C.
2013-07-01
A new time-dependent neutron transport method based on the method of characteristics (MOC) has been developed. Whereas most spatial kinetics methods treat time dependence through temporal discretization, this new method treats time dependence by defining the characteristics to span space and time. In this implementation regions are defined in space-time where the thickness of the region in time fulfills an analogous role to the time step in discretized methods. The time dependence of the local source is approximated using a truncated Taylor series expansion with high order derivatives approximated using backward differences, permitting the solution of the resulting space-time characteristic equation. To avoid a drastic increase in computational expense and memory requirements due to solving many discrete characteristics in the space-time planes, the temporal variation of the boundary source is similarly approximated. This allows the characteristics in the space-time plane to be represented analytically rather than discretely, resulting in an algorithm comparable in implementation and expense to one that arises from conventional time integration techniques. Furthermore, by defining the boundary flux time derivative in terms of the preceding local source time derivative and boundary flux time derivative, the need to store angularly-dependent data is avoided without approximating the angular dependence of the angular flux time derivative. The accuracy of this method is assessed through implementation in the neutron transport code DeCART. The method is employed with variable-order local source representation to model a TWIGL transient. The results demonstrate that this method is accurate and more efficient than the discretized method. (authors)
NASA Astrophysics Data System (ADS)
Boukhili, W.; Mahdouani, M.; Bourguiga, R.; Puigdollers, J.
2015-07-01
Bottom-contact p-type small-molecule copper phthalocyanine (CuPc) thin film transistors (TFTs) with different channel lengths have been fabricated by thermal evaporation. The influence of the channel length on the current-voltage characteristics of the fabricated transistors were investigated in the linear and saturation regimes. The devices exhibit excellent p-type operation characteristics. Results show that devices with smaller channel length (L = 2.5 μm and 5 μm) present the best electrical performance, in terms of drain current value, field effect mobility and subthreshold slope. Saturation field-effect mobilities of 1.7 × 10-3 cm2 V-1 s-1 and 1 × 10-3 cm2 V-1 s-1 were obtained for TFTs with channel lengths of L = 2.5 μm and L = 5 μm, respectively. Transmission line method was used to study the dependence of the contact resistance with the channel length. Contact resistance becomes dominant with respect to the channel resistance only in the case of short channel devices (L = 2.5 μm and 5 μm). It was also found that the field effect mobility is extremely dependent on the channel length dimension. Finally, an analytical model has been developed to reproduce the dependence of the transfer characteristics with the channel length and the obtained data are in good agreement with the experimental results for all fabricated devices.
NASA Technical Reports Server (NTRS)
Abel, I.
1979-01-01
An analytical technique for predicting the performance of an active flutter-suppression system is presented. This technique is based on the use of an interpolating function to approximate the unsteady aerodynamics. The resulting equations are formulated in terms of linear, ordinary differential equations with constant coefficients. This technique is then applied to an aeroelastic model wing equipped with an active flutter-suppression system. Comparisons between wind-tunnel data and analysis are presented for the wing both with and without active flutter suppression. Results indicate that the wing flutter characteristics without flutter suppression can be predicted very well but that a more adequate model of wind-tunnel turbulence is required when the active flutter-suppression system is used.
Analysis of self-similar problems of imploding shock waves by the method of characteristics
NASA Astrophysics Data System (ADS)
Nakamura, Y.
1983-05-01
The asymptotic self-similar form of cylindrically or spherically imploding shock waves is extracted by numerically solving non-self-similar problems. The shock wave is generated by a contracting piston with finite initial velocity. For the initial shock motion, a perturbation method is used to determine the starting condition for the numerical calculation. Propagation of the shock wave and flow field properties are obtained and the transition of the non-self-similar motion of the shock wave into the self-similar one is presented. Good agreement between self-similar exponents determined from the variation of the shock strength and those calculated by Guderley is obtained.
Bain, R.J. . Dept. of Geology)
1993-03-01
Fluidized bed combustion of coal is considered one of the more promising clean coal technologies for the future. While much research has gone into the design and operation of FBC units, there is little concern for what characterizes a high quality sorbent and the source of such a sorbent. Carbonate rocks, limestone and dolomite, have been tested extensively as sorbents and primarily two rock characteristics appear to significantly control reactivity: composition and texture. Calcium carbonate is more reactive than magnesium carbonate where all other rock characteristics are the same. In considering texture, highest reactivity is measured for carbonate rocks which consist of homogeneous, euhedral crystals ranging in size from .05 to .2 mm and which possess uniform intercrystalline porosity. The most reactive material possesses both high calcium content, uniform microcrystalline texture and intercrystalline porosity, however, such material is not very abundant in nature and is not locally available to midcontinent facilities. Sucrosic dolomite, which possesses uniform microcrystalline texture and intercrystalline porosity has high rank reactivity. While this rock is quite common, it occurs as beds, generally less than twenty feet thick, interlayered with less reactive dolomite types. Therefore, without selective quarrying methods, production of sorbent with uniformly high reactivity will be impossible.
Zucker, Kenneth J; Bradley, Susan J; Owen-Anderson, Allison; Kibblewhite, Sarah J; Wood, Hayley; Singh, Devita; Choi, Kathryn
2012-01-01
This study provided a descriptive and quantitative comparative analysis of data from an assessment protocol for adolescents referred clinically for gender identity disorder (n = 192; 105 boys, 87 girls) or transvestic fetishism (n = 137, all boys). The protocol included information on demographics, behavior problems, and psychosexual measures. Gender identity disorder and transvestic fetishism youth had high rates of general behavior problems and poor peer relations. On the psychosexual measures, gender identity disorder patients had considerably greater cross-gender behavior and gender dysphoria than did transvestic fetishism youth and other control youth. Male gender identity disorder patients classified as having a nonhomosexual sexual orientation (in relation to birth sex) reported more indicators of transvestic fetishism than did male gender identity disorder patients classified as having a homosexual sexual orientation (in relation to birth sex). The percentage of transvestic fetishism youth and male gender identity disorder patients with a nonhomosexual sexual orientation self-reported similar degrees of behaviors pertaining to transvestic fetishism. Last, male and female gender identity disorder patients with a homosexual sexual orientation had more recalled cross-gender behavior during childhood and more concurrent cross-gender behavior and gender dysphoria than did patients with a nonhomosexual sexual orientation. The authors discuss the clinical utility of their assessment protocol. PMID:22390530
Broyles, D L; Nielsen, R G; Bussett, E M; Lu, W D; Mizrahi, I A; Nunnelly, P A; Ngo, T A; Noell, J; Christenson, R H; Kress, B C
1998-10-01
The performance characteristics of the Tandem-MP Ostase assay, a new microplate immunoassay for bone-specific alkaline phosphatase (bone ALP; EC 3.1.3.1) in human sera, are described. Bone ALP is bound to streptavidin-coated microwells by a single biotinylated anti-bone ALP monoclonal antibody. Antigen is detected by the addition of p-nitrophenyl phosphate. The assay is performed at room temperature in <90 min. Imprecision was 2.3-6.1% with a detection limit of 0.6 microg/L. Method comparison of bone ALP measurements with the Tandem-MP Ostase assay and the mass-based Tandem-R Ostase assay (n = 285) indicated regression statistics of Tandem-MP Ostase = 1.03 Tandem-R Ostase + 0.22 microg/L, S(y/x) = 4.0 microg/L, r = 0.97. Serum bone ALP values in apparently healthy men and in pre- and postmenopausal women were also similar between the two Ostase assay formats. Liver ALP reactivity determined using the slope and heat inactivation methods was similar in both Ostase assays. Liver ALP reactivity ranged from 3 microg/L (heat inactivation) to 6 microg/L (slope method) per 100 U/L of liver ALP activity, whereas bone ALP reactivity was 37 microg/L per 100 U/L of bone ALP activity, indicating a liver ALP relative reactivity of 8.1-16.2%. Similar results were obtained with the Alkphase-B bone ALP immunoassay. The Tandem-MP Ostase bone ALP assay demonstrated increased concentrations of serum bone ALP in conditions where bone metabolism is increased and showed a rapid, temporal decrease in serum bone ALP in Paget disease patients on bisphosphonate therapy. In conclusion, the Tandem-MP Ostase assay for serum bone ALP is a rapid, simple, robust nonisotopic alternative to the Tandem-R Ostase immunoradiometric assay that provides an accurate and sensitive assessment of bone turnover. PMID:9761247
Coxell, Adrian; King, Michael; Mezey, Gillian; Gordon, Dawn
1999-01-01
Objective To identify the lifetime prevalence of non-consensual sexual experiences in men, the relationship between such experiences as a child and as an adult, associated psychological and behavioural problems, and help received. Design Cross sectional survey. Setting England. Subjects 2474 men (mean age 46 years) attending one of 18 general practices. Main outcome measures Experiences of non-consensual and consensual sex before and after the age of 16 years—that is, as a child and adult respectively—psychological problems experienced for more than 2 weeks at any one time, use of alcohol (CAGE questionnaire), self harm, and help received. Results 2474 of 3142 men (79%) agreed to participate; 71/2468 (standardised rate 2.89%, 95% confidence interval 2.21% to 3.56%) reported non-consensual sexual experiences as adults, 128/2423 (5.35%, 4.39% to 6.31%) reported non-consensual sexual experiences as children, and 185/2406 (7.66%, 6.54% to 8.77%) reported consensual sexual experiences as children that are illegal under English law. Independent predictors of non-consensual sex as adults were reporting male sexual partners (odds ratio 6.0, 2.6 to 13.5), non-consensual sex in childhood (4.2, 2.1 to 8.6), age (0.98, 0.96 to 0.99), and sex of interviewer (2.0, 1.2 to 3.5). Non-consensual sexual experiences were associated with a greater prevalence of psychological problems, alcohol misuse, and self harm. These sexual experiences were also significant predictors of help received from mental health professionals. Conclusion Almost 3% of men in England report non-consensual sexual experiences as adults. Medical professionals need to be aware of the range of psychological difficulties in men who have had such experiences. They also need to be aware of the relationship between sexual experiences in childhood and adulthood in men. Key messagesAlmost 3% of men report non-consensual sexual experiences as adultsOver 5% of men report sexual abuse as childrenNon-consensual sexual
Nower, Lia; Blaszczynski, Alex
2008-09-01
Gambling among older adults appears to be increasing, though little is known about the characteristics of older adult problem gamblers. The purpose of this study was to compare older adults to younger and middle-aged adults in a cohort of problem gamblers participating in a state-administered casino self-exclusion program. Self-reported problem gamblers (N = 1,601) who voluntary banned themselves from Missouri casinos from 2001 to 2003 were categorized by age as younger adults (ages 21 to 35; n = 490), middle-aged adults (ages 36 to 55; n = 950), and older adults (ages 56 to 79; n = 161), and were compared with respect to demographic variables, gambling participation, and reasons for self-exclusion. Older adult self-excluders typically began gambling in midlife, experienced gambling problems around age 60, reported preferences for nonstrategic forms of gambling, and identified fear of suicide as the primary reason for self-excluding. Implications for intervention, prevention and treatment are discussed. PMID:18808247
Devereux, J J; Rydstedt, L W; Cropley, M
2011-09-01
From an original sample of 2454 participants free of self-reported psychological distress, 1463 workers completed a 15-month follow-up. Baseline measures included exposure to job demands, decision latitude, social support and need for recovery. Psychological distress was assessed using the General Health Questionnaire at baseline and at follow-up. The findings showed that medium and high exposure to job demands and social support increased the risk of reporting psychological distress at 15-months (relative risk (RR) = 1.65, 1.45). The highest adjusted RR was observed for workers reporting a high need for recovery after work (RR 2.12, 1.90) and this finding was independent of the effects of job demands, decision latitude and social support. Neither decision latitude, nor low back problems increased the risk of reporting future psychological distress, although neck problems (RR = 1.66) and hand/wrist problems (RR = 1.45) did. It was concluded that need for recovery appears to be an important indicator of individual workers who are at risk of developing psychological distress long term. STATEMENT OF RELEVANCE: This paper reports the findings of a longitudinal study showing that need for recovery from work was the strongest predictor, relative to psychosocial work characteristics (job demands, decision latitude and social support), and musculoskeletal problems, of psychological distress 15 months later in individuals initially free from distress. PMID:21851291
Ozgun, Ozlem Mittra, Raj; Kuzuoglu, Mustafa
2009-04-01
In this paper, we introduce a parallelized version of a novel, non-iterative domain decomposition algorithm, called Characteristic Basis Finite Element Method (CBFEM-MPI), for efficient solution of large-scale electromagnetic scattering problems, by utilizing a set of specially defined characteristic basis functions (CBFs). This approach is based on the decomposition of the computational domain into a number of non-overlapping subdomains wherein the CBFs are generated by employing a novel procedure, which differs from all those that have been used in the past. Clearly, the CBFs are obtained by calculating the fields radiated by a finite number of dipole-type sources, which are placed hypothetically along the boundary of the conducting object. The major advantages of the proposed technique are twofold: (i) it provides a substantial reduction in the matrix size, and thus, makes use of direct solvers efficiently and (ii) it enables the utilization of parallel processing techniques that considerably decrease the overall computation time. We illustrate the application of the proposed approach via several 3D electromagnetic scattering problems.
The main characteristics, problems, and prospects for Western European coastal seas.
Dauvin, Jean-Claude
2008-01-01
Located to the far West of Western Europe, France has a western maritime coastal zone of more than 3800 km, which is widely influenced by the North-eastern Atlantic. The English Channel, an epi-continental shallow sea with very strong tides, runs along 650 km of the French coast and 1100 km of the English coast. It is also a bio-geographical crossroad encompassing a much wider range of ecological conditions than other European seas. France's Atlantic coast north of the Gironde estuary is a succession of rocky and sandy shorelines, including a sizeable intertidal zone, a wide continental shelf, and two major estuaries (Loire and Gironde). South of the Gironde, the 260 km of coastline is low, sandy and straight, with a narrowing continental shelf further on South due to the presence of the Cape Breton canyon in the bathyal and abyssal zones. Interface between the continental and oceanic systems, these bordering seas--North Sea, English Channel and Atlantic Ocean--have been the subject of many recent research programmes (the European Mast-FLUXMANCHE and INTERREG programmes; the national coastal environment programme and the LITEAU programme in France), designed to improve comprehension of the functions, production, and dynamics of these seas as well as their future evolution. Given the many conflicting practices in these littoral zones, integrated coastal zone management appears to be essential in order to cope with both natural phenomena, such as the infilling of estuarine zones, cliff erosion, and rising sea levels, and chronic anthropogenic pressures, such as new harbour installations (container dikes, marinas), sea aggregate extraction for human constructions, and offshore wind mill farms. This article provides as complete an overview as possible of the research projects on these bordering seas, both those that have recently been accomplished and those that are currently in progress, in order to highlight the main characteristics of these ecosystems and to
Cater, Asa K; Andershed, Anna-Karin; Andershed, Henrik
2014-08-01
The present study examines multiple types of victimization simultaneously, their prevalence and characteristics in childhood and adolescence, and it examines the associations between victimization and poly-victimization on the one hand and single and multiple mental health and behavioral problems on the other. The sample consisted of 2,500 Swedish young adults (20-24 years) who provided detailed report of multiple types of lifetime victimization and current health and behaviors via an interview and a questionnaire. Results showed that it was more common to be victimized in adolescence than in childhood and more common to be victimized repeatedly rather than a single time, among both males and females. Males and females were victimized in noticeably different ways and partially at different places and by different perpetrators. With regard to mental health and behavioral problems, anxiety, post-traumatic stress, self-harm, and criminality were clearly overrepresented among both males and females who had experienced any type of victimization. Poly-victimization was related to single and multiple mental health and behavioral problems among both males and females. We conclude that professionals need to conduct thorough evaluations of victimization when completing mental health assessments among troubled youths, and that youth might benefit from the development of interventions for poly-victimized youth. PMID:24685360
Extreme Scale Visual Analytics
Wong, Pak C.; Shen, Han-Wei; Pascucci, Valerio
2012-05-08
Extreme-scale visual analytics (VA) is about applying VA to extreme-scale data. The articles in this special issue examine advances related to extreme-scale VA problems, their analytical and computational challenges, and their real-world applications.
Multimedia Analysis plus Visual Analytics = Multimedia Analytics
Chinchor, Nancy; Thomas, James J.; Wong, Pak C.; Christel, Michael; Ribarsky, Martin W.
2010-10-01
Multimedia analysis has focused on images, video, and to some extent audio and has made progress in single channels excluding text. Visual analytics has focused on the user interaction with data during the analytic process plus the fundamental mathematics and has continued to treat text as did its precursor, information visualization. The general problem we address in this tutorial is the combining of multimedia analysis and visual analytics to deal with multimedia information gathered from different sources, with different goals or objectives, and containing all media types and combinations in common usage.
Analytical and simulator study of advanced transport
NASA Technical Reports Server (NTRS)
Levison, W. H.; Rickard, W. W.
1982-01-01
An analytic methodology, based on the optimal-control pilot model, was demonstrated for assessing longitidunal-axis handling qualities of transport aircraft in final approach. Calibration of the methodology is largely in terms of closed-loop performance requirements, rather than specific vehicle response characteristics, and is based on a combination of published criteria, pilot preferences, physical limitations, and engineering judgment. Six longitudinal-axis approach configurations were studied covering a range of handling qualities problems, including the presence of flexible aircraft modes. The analytical procedure was used to obtain predictions of Cooper-Harper ratings, a solar quadratic performance index, and rms excursions of important system variables.
NASA Astrophysics Data System (ADS)
Petrov, D. I.; Petrov, I. B.; Favorskaya, A. V.; Khokhlov, N. I.
2016-06-01
The goal of this paper is the numerical solution of direct problems concerning hydrocarbon seismic exploration on the Arctic shelf. The task is addressed by solving a complete system of linear elasticity equations and a system of acoustic field equations. Both systems are solved by applying the grid-characteristic method, which takes into account all wave processes in a detailed and physically correct manner and produces a solution near the boundaries and interfaces of the integration domain, including the interface between the acoustic and linear elastic media involved. The seismograms and wave patterns obtained by numerically solving these systems are compared. The effect of ice structures on the resulting wave patterns is examined.
Kariminia, Samira; Shamsipur, Ali; Shamsipur, Mojtaba
2016-09-10
A pH-responsive drug carrier based on chitosan coated iron oxide nanoparticles (CS-Fe3O4) for prolonged antibiotic release in a controlled manner is reported. As an antibiotic drug model, ciprofloxacin was loaded onto the nanocarrier via H-bonding interactions. The nanoparticles were characterized using scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, photon correlation spectroscopy and Fourier transform infrared spectroscopy. The particle size of CS-Fe3O4 nanoparticles were found to lie in the range of 30-80nm. The analytical characteristics of the designed system were thoroughly investigated. The in vitro drug loading at pH 4.8 and release kinetics at pH 7.4 studies revealed that the drug delivery system can take 99% of ciprofloxacin load and quantitatively release the drug over a sustained period of 5 days. The release kinetics study indicated that the system follows a zero order kinetics via a diffusion-controlled mechanism. These results indicated that CS-Fe3O4 nanoparticles have the potential for use as controlled antibiotic delivery systems through oral administration by avoiding the drug release in the highly acidic gastric fluid region of the stomach. Furthermore, the ability of low-frequency ultrasound in fast release of the encapsulated drug in less than 60min from the CS-Fe3O4 nanoparticles in a controlled manner was confirmed. PMID:27497305
This manual primarily provides the pesticide chemist with a systematic protocol for the prevention and control of analytical procedures which arise in the analysis of human or environmental media. The sections dealing with inter- and intra-laboratory quality control, the evaluati...
NASA Astrophysics Data System (ADS)
Fahnestock, Eugene Gregory
The Full Two-Body-Problem (F2BP) describes the dynamics of two unconstrained rigid bodies in close proximity, having arbitrary spatial distribution of mass, charge, or similar field quantity, and interacting through a mutual potential dependent on that distribution. While the F2BP has applications in areas as wide ranging as molecular dynamics to satellite formation flying, this dissertation focuses on its application to natural bodies in space with nontrivial mass distribution interacting through mutual gravitational potential, i.e. binary asteroids. This dissertation first describes further development and implementation of methods for accurate and efficient F2BP propagation based upon a flexible method for computing the mutual potential between bodies modeled as homogenous polyhedra. Next application of these numerical tools to the study of binary asteroid (66391) 1999 KW4 is summarized. This system typifies the largest class of NEO binaries, which includes nearly half of them, characterized by a roughly oblate spheroid primary rotating rapidly and roughly triaxial ellipsoid secondary in on-average synchronous rotation. Thus KW4's dynamics generalize to any member of that class. Analytical formulae are developed which separately describe the effects of primary oblateness and secondary triaxial ellipsoid shape on frequencies of system motions revealed through the F2BP simulation. These formulae are useful for estimating inertia elements and highest-level internal mass distributions of bodies in any similar system, simply from standoff observation of these motion frequencies. Finally precise dynamical simulation and analysis of the motion of test particles within the time-varying gravity field of the F2BP system is detailed. This Restricted Full-detail Three-Body-Problem encompasses exploration of three types of particle motion within a binary asteroid: (1) Orbital motion such as that for a spacecraft flying within the system about the primary, secondary, or
NASA Astrophysics Data System (ADS)
Felton, E. Anne
2002-10-01
. Recognition and description of rocky shoreline deposits are crucial for correctly interpreting the geological history of oceanic and volcanic arc islands, for distinguishing between ancient tsunami and storm deposits, and for interpreting coarse-grained deposits preserved on high energy coasts of continents. Problems include not only the absence of appropriate sedimentary facies models linking rocky shoreline deposits and environments but also, until recently, lack of a systematic descriptive scheme applicable to coarse gravel deposits generally. Two complementary methods serve to integrate the wide range of bed and clast attributes and parameters which characterize complex coarse gravel deposits. The composition and fabric (CAF) method has a materials focus, providing detailed description of attributes of the constituent clasts, petrology, the proportions of gravel, sand and mud, and the ways in which these materials are organized. The sedimentary facies model building (FMB) method emphasizes the organization of a deposit on a bed-by-bed basis to identify facies and infer depositional processes. The systematic use of a comprehensive gravel fabric and petrography log (GFPL), in conjunction with detailed vertical profiles, provides visual representations of a range of deposit characteristics. Criteria useful for distinguishing sedimentary facies in the Hulopoe Gravel are: grain-size modes, amount of matrix, bed geometry, sedimentary structures, bed fabric and clast roundness.
NASA Astrophysics Data System (ADS)
Lesnichii, V. V.; Petrov, N. V.; Cheremkhin, P. A.
2013-10-01
The possibility of using commercial digital cameras that support image saving in the RAW format in scientific applications for measuring spatial intensity distributions in different ranges of the visible spectrum is considered. Spectral characteristics of photo sensors were measured for three digital cameras: Canon EOS 1000D, Nikon D50, and Nikon D90. Ways of applying spectral characteristics in problems of improving the quality of multicolor digital holograms are considered.
NASA Astrophysics Data System (ADS)
Zaki, Wael; Moumni, Ziad
2015-04-01
We propose two frameworks for the derivation of constitutive models for solids undergoing phase transformations. The first is based on the assumption that solid phases within the material are finely mixed whereas the second considers the material as a heterogeneous solution of phase fragments and uses the homogenization theory to derive equilibrium conditions for displacement fields and phase distributions. It is shown that in the case of reversible phase transformation, the energy of the material can be obtained by taking the convex envelope of the energy functions of the constituent phases. As an application, a schematic model is derived for an idealized shape memory alloy and used to obtain a novel analytical solution for the problem of semi-infinite mode III crack in this material. The derivation of the analytical solution uses the hodograph method to map Cartesian coordinates into the hodograph plane. The resulting boundary-value problem for the mode III crack considered becomes analytically tractable for the idealized shape memory alloy considered and leads to closed-form expressions for the displacement and phase volume fraction fields near the crack tip as well as for the boundaries between different phase regions.
Dixon, Robert L.; Boone, John M.
2011-07-15
Purpose: Knowledge of the complete axial dose profile f(z), including its long scatter tails, provides the most complete (and flexible) description of the accumulated dose in CT scanning. The CTDI paradigm (including CTDI{sub vol}) requires shift-invariance along z (identical dose profiles spaced at equal intervals), and is therefore inapplicable to many of the new and complex shift-variant scan protocols, e.g., high dose perfusion studies using variable (or zero) pitch. In this work, a convolution-based beam model developed by Dixon et al.[Med. Phys. 32, 3712-3728, (2005)] updated with a scatter LSF kernel (or DSF) derived from a Monte Carlo simulation by Boone [Med. Phys. 36, 4547-4554 (2009)] is used to create an analytical equation for the axial dose profile f(z) in a cylindrical phantom. Using f(z), equations are derived which provide the analytical description of conventional (axial and helical) dose, demonstrating its physical underpinnings; and likewise for the peak axial dose f(0) appropriate to stationary phantom cone beam CT, (SCBCT). The methodology can also be applied to dose calculations in shift-variant scan protocols. This paper is an extension of our recent work Dixon and Boone [Med. Phys. 37, 2703-2718 (2010)], which dealt only with the properties of the peak dose f(0), its relationship to CTDI, and its appropriateness to SCBCT. Methods: The experimental beam profile data f(z) of Mori et al.[Med. Phys. 32, 1061-1069 (2005)] from a 256 channel prototype cone beam scanner for beam widths (apertures) ranging from a = 28 to 138 mm are used to corroborate the theoretical axial profiles in a 32 cm PMMA body phantom. Results: The theoretical functions f(z) closely-matched the central axis experimental profile data{sup 11} for all apertures (a = 28 -138 mm). Integration of f(z) likewise yields analytical equations for all the (CTDI-based) dosimetric quantities of conventional CT (including CTDI{sub L} itself) in addition to the peak dose f(0) relevant to
Mahmood, Mohammed Shuker
2007-12-26
Numerical scheme based on the modified method of characteristics with adjusted advection combined with a relaxation scheme for solving strongly nonlinear degenerate convection diffusion problem which arises in the contaminant transport in porous media with dual porosity. A series of computational experiments and comparisons with other solutions are carried out to illustrate the rate of convergence, the behavior and the capability of the scheme.
ERIC Educational Resources Information Center
Akyuz, Halil Ibrahim; Keser, Hafize
2015-01-01
The aim of this study is to investigate the effect of an educational agent, used in online task based learning media, and its form characteristics on problem solving ability perceptions of students. 2x2 factorial design is used in this study. The first study factor is the role of the educational agent and the second factor is form characteristics…
ERIC Educational Resources Information Center
Seiverling, Laura; Hendy, Helen M.; Williams, Keith
2011-01-01
The present study evaluated the 23-item Screening Tool for Feeding Problems (STEP; Matson & Kuhn, 2001) with a sample of children referred to a hospital-based feeding clinic to examine the scale's psychometric characteristics and then demonstrate how a children's revision of the STEP, the STEP-CHILD is associated with child and parent variables.…
NASA Technical Reports Server (NTRS)
Degani, Asaf; Mitchell, Christine M.; Chappell, Alan R.; Shafto, Mike (Technical Monitor)
1995-01-01
Task-analytic models structure essential information about operator interaction with complex systems, in this case pilot interaction with the autoflight system. Such models serve two purposes: (1) they allow researchers and practitioners to understand pilots' actions; and (2) they provide a compact, computational representation needed to design 'intelligent' aids, e.g., displays, assistants, and training systems. This paper demonstrates the use of the operator function model to trace the process of mode engagements while a pilot is controlling an aircraft via the, autoflight system. The operator function model is a normative and nondeterministic model of how a well-trained, well-motivated operator manages multiple concurrent activities for effective real-time control. For each function, the model links the pilot's actions with the required information. Using the operator function model, this paper describes several mode engagement scenarios. These scenarios were observed and documented during a field study that focused on mode engagements and mode transitions during normal line operations. Data including time, ATC clearances, altitude, system states, and active modes and sub-modes, engagement of modes, were recorded during sixty-six flights. Using these data, seven prototypical mode engagement scenarios were extracted. One scenario details the decision of the crew to disengage a fully automatic mode in favor of a semi-automatic mode, and the consequences of this action. Another describes a mode error involving updating aircraft speed following the engagement of a speed submode. Other scenarios detail mode confusion at various phases of the flight. This analysis uses the operator function model to identify three aspects of mode engagement: (1) the progress of pilot-aircraft-autoflight system interaction; (2) control/display information required to perform mode management activities; and (3) the potential cause(s) of mode confusion. The goal of this paper is twofold
NASA Astrophysics Data System (ADS)
Moussaddy, Hadi
The Representative Volume Element (RVE) plays a central role in the mechanics of composite materials with respect to predicting their effective properties. Numerical homogenization delivers accurate estimations of composite effective properties when associated with a RVE. In computational homogenization, the RVE refers to an ensemble of random material volumes that yield, by an averaging procedure, the effective properties of the bulk material, within a tolerance. A large diversity of RVE quantitative definitions, providing computational methods to estimate the RVE size, are found in literature. In this study, the ability of the different RVE definitions to yield accurate effective properties is investigated. The assessment is conducted on a specific random microstructure, namely an elastic two-phase three dimensional composite reinforced by randomly oriented fibers. Large scale finite element simulations of material volumes of different sizes are performed on high performance computational servers using parallel computing. The materials volumes are virtually generated and subjected to periodic boundary conditions. It is shown that most popular RVE definitions, based on convergence of the properties when increasing the material volume, yields inaccurate effective properties. A new RVE definition is introduced based on the statistical variations of the properties computed from material volumes. It is shown to produce more accurate estimations of the effective properties. In addition, the new definition produced RVE that are smaller in size than that of other RVE definitions ; also the number of necessary finite element simulations to determine the RVE is substantially reduced. The computed effective properties are compared to that of analytical models. The comparisons are performed for a wide range of fibers aspect ratios (up to 120), properties contrast (up to 300) and volume fractions only up to 20% due to computational limits. The Mori-Tanaka model and the two
NASA Astrophysics Data System (ADS)
Bellouquid, Abdelghani
2015-03-01
The new systems approach in biological sciences proposed in [1] is a constructive reply to the hints of the scientific community [2] and opens new research paths toward developments of new mathematical methods to model the living matter. This comment focuses on some analytic and modeling issues which are somewhat related to my personal scientific knowhow. I look forward to the answer to them as a critical analysis on the topics presented in the following might contribute to research activity in the field and, specifically, to the complex interplay between mathematics and biology. Therefore, after some introductory comment, I pose, for each issue, a specific question.
NASA Astrophysics Data System (ADS)
Tomarov, G. V.; Povarov, V. P.; Shipkov, A. A.; Gromov, A. F.; Kiselev, A. N.; Shepelev, S. V.; Galanin, A. V.
2015-02-01
Specific features relating to development of the information-analytical system on the problem of flow-accelerated corrosion of pipeline elements in the secondary coolant circuit of the VVER-440-based power units at the Novovoronezh nuclear power plant are considered. The results from a statistical analysis of data on the quantity, location, and operating conditions of the elements and preinserted segments of pipelines used in the condensate-feedwater and wet steam paths are presented. The principles of preparing and using the information-analytical system for determining the lifetime to reaching inadmissible wall thinning in elements of pipelines used in the secondary coolant circuit of the VVER-440-based power units at the Novovoronezh NPP are considered.
ERIC Educational Resources Information Center
Maikovich-Fong, Andrea Kohn; Jaffee, Sara R.
2010-01-01
Objective: The first objective of this study was to test for sex differences in four childhood sexual abuse characteristics--penetration, substantiation, perpetrator familial status, and multi-maltreatment--in a national sample of youth. The second objective was to test for sex differences in how these abuse characteristics were associated with…
NASA Technical Reports Server (NTRS)
Flannelly, W. G.; Fabunmi, J. A.; Nagy, E. J.
1981-01-01
Analytical methods for combining flight acceleration and strain data with shake test mobility data to predict the effects of structural changes on flight vibrations and strains are presented. This integration of structural dynamic analysis with flight performance is referred to as analytical testing. The objective of this methodology is to analytically estimate the results of flight testing contemplated structural changes with minimum flying and change trials. The category of changes to the aircraft includes mass, stiffness, absorbers, isolators, and active suppressors. Examples of applying the analytical testing methodology using flight test and shake test data measured on an AH-1G helicopter are included. The techniques and procedures for vibration testing and modal analysis are also described.
Demidenko, Eugene
2011-01-01
An analytic solution of the potential distribution on a 2D homogeneous disk for electrical impedance tomography under the complete electrode model is expressed via an infinite system of linear equations. For the shunt electrode model with two electrodes, our solution coincides with the previously derived solution expressed via elliptic integral (Pidcock et al 1995). The Dirichlet-to-Neumann map is derived for statistical estimation via nonlinear least squares. The solution is validated in phantom experiments and applied for breast contact impedance estimation in vivo. Statistical hypothesis testing is used to test whether the contact impedances are the same across electrodes or all equal zero. Our solution can be especially useful for a rapid real-time test for bad surface contact in clinical setting. PMID:21799240
ERIC Educational Resources Information Center
Jansen, Pauline W.; Raat, Hein; Mackenbach, Johan P.; Jaddoe, Vincent W. V.; Hofman, Albert; van Oort, Floor V.; Verhulst, Frank C.; Tiemeier, Henning
2010-01-01
In many societies the prevalence of behavioural problems in school-aged children varies by national origin. We examined the association between national origin and behavioural problems in 1 1/2-year-old children. Data on maternal national origin and the Child Behavior Checklist for toddlers (n = 4943) from a population-based cohort in the…
ERIC Educational Resources Information Center
Kelly, William E.
2005-01-01
This study explored the relationship between night-sky watching and self-reported cognitive variables: need for cognition and social problem-solving. University students (N = 140) completed the Noctcaelador Inventory, the Need for Cognition Scale, and the Social Problem Solving Inventory. The results indicated that an interest in the night-sky was…
ERIC Educational Resources Information Center
Young, Martin; Stevens, Matthew
2009-01-01
To explore the structure of gambling participation and its association with problem gambling, we draw upon Caillois's distinction between games based on competition (i.e. "agon") and those based on chance (i.e. "alea"). The idea that "alea" and "agon" are socially patterned and associated with differing levels of problem gambling, as measured by…
NASA Astrophysics Data System (ADS)
Heineken, Wolfram; Kunik, Matthias
2008-05-01
A finite volume method with grid adaption is applied to two hyperbolic problems: the ultra-relativistic Euler equations, and a scalar conservation law. Both problems are considered in two space dimensions and share the common feature of moving shock waves. In contrast to the classical Euler equations, the derivation of appropriate initial conditions for the ultra-relativistic Euler equations is a non-trivial problem that is solved using one-dimensional shock conditions and the Lorentz invariance of the system. The discretization of both problems is based on a finite volume method of second order in both space and time on a triangular grid. We introduce a variant of the min-mod limiter that avoids unphysical states for the Euler system. The grid is adapted during the integration process. The frequency of grid adaption is controlled automatically in order to guarantee a fine resolution of the moving shock fronts. We introduce the concept of "width refinement" which enlarges the width of strongly refined regions around the shock fronts; the optimal width is found by a numerical study. As a result we are able to improve efficiency by decreasing the number of adaption steps. The performance of the finite volume scheme is compared with several lower order methods.
ERIC Educational Resources Information Center
Crone, Regina M.; Mehta, Smita Shukla
2016-01-01
Setting variables such as location of parent training, programming with common stimuli, generalization of discrete responses to non-trained settings, and subsequent reduction in child problem behavior may influence the effectiveness of interventions. The purpose of this study was to evaluate the effectiveness of home-versus clinic-based training…
NASA Technical Reports Server (NTRS)
Tarnopolskiy, V. I.
1978-01-01
Widely used remote probing methods, and especially the multispectral method, for studying the earth from aerospace platforms necessitate the systematization and accumulation of data on the relationships between remote observations and measured parameters and characteristic properties and conditions of phenomena on the earth's surface. Data were presented on the optical characteristics of natural objects which arise during observations of these objects over a wide spectral interval which encompasses solar radiation reflected by the object as well as the object's inherent thermal radiation. The influence of the earth's atmosphere on remote measurements and several problems in simulation and calculation are discussed.
Newbury, Dale E
2005-12-01
Automatic qualitative analysis for peak identification is a standard feature of virtually all modern computer-aided analysis software for energy dispersive X-ray spectrometry with electron excitation. Testing of recently installed systems from four different manufacturers has revealed the occasional occurrence of misidentification of peaks of major constituents whose concentrations exceeded 0.1 mass fraction (10 wt%). Test materials where peak identification failures were observed included ZnS, KBr, FeS2, tantalum-niobium alloy, NIST Standard Reference Material 482 (copper-gold alloy), Bi2Te3, uranium-rhodium alloys, platinum-chromium alloy, GaAs, and GaP. These misidentifications of major constituents were exacerbated when the incident beam energy was 10 keV or lower, which restricted or excluded the excitation of the high photon energy K- and L-shell X-rays where multiple peaks, for example, Kalpha (K-L2,3)-Kbeta (K-M2,3); Lalpha (L3-M4,5)-Lbeta (L2-M4)-Lgamma (L2-N4), are well resolved and amenable to identification with high confidence. These misidentifications are so severe as to properly qualify as blunders that present a serious challenge to the credibility of this critical analytical technique. Systematic testing of a peak identification system with a suite of diverse materials can reveal the specific elements and X-ray peaks where failures are likely to occur. PMID:17481333
NASA Astrophysics Data System (ADS)
Newbury*, Dale E.
2005-12-01
Automatic qualitative analysis for peak identification is a standard feature of virtually all modern computer-aided analysis software for energy dispersive X-ray spectrometry with electron excitation. Testing of recently installed systems from four different manufacturers has revealed the occasional occurrence of misidentification of peaks of major constituents whose concentrations exceeded 0.1 mass fraction (10 wt%). Test materials where peak identification failures were observed included ZnS, KBr, FeS2, tantalum-niobium alloy, NIST Standard Reference Material 482 (copper gold alloy), Bi2Te3, uranium rhodium alloys, platinum chromium alloy, GaAs, and GaP. These misidentifications of major constituents were exacerbated when the incident beam energy was 10 keV or lower, which restricted or excluded the excitation of the high photon energy K- and L-shell X-rays where multiple peaks, for example, K[alpha] (K-L2,3) K[beta] (K-M2,3); L[alpha] (L3-M4,5) L[beta] (L2-M4) L[gamma] (L2-N4), are well resolved and amenable to identification with high confidence. These misidentifications are so severe as to properly qualify as blunders that present a serious challenge to the credibility of this critical analytical technique. Systematic testing of a peak identification system with a suite of diverse materials can reveal the specific elements and X-ray peaks where failures are likely to occur.
Pírez, Macarena; Gonzalez-Sapienza, Gualberto; Sienra, Daniel; Ferrari, Graciela; Last, Michael; Last, Jerold A; Brena, Beatriz M
2013-01-15
In recent years, the international demand for commodities has prompted enormous growth in agriculture in most South American countries. Due to intensive use of fertilizers, cyanobacterial blooms have become a recurrent phenomenon throughout the continent, but their potential health risk remains largely unknown due to the lack of analytical capacity. In this paper we report the main results and conclusions of more than five years of systematic monitoring of cyanobacterial blooms in 20 beaches of Montevideo, Uruguay, on the Rio de la Plata, the fifth largest basin in the world. A locally developed microcystin ELISA was used to establish a sustainable monitoring program that revealed seasonal peaks of extremely high toxicity, more than one-thousand-fold greater than the WHO limit for recreational water. Comparison with cyanobacterial cell counts and chlorophyll-a determination, two commonly used parameters for indirect estimation of toxicity, showed that such indicators can be highly misleading. On the other hand, the accumulated experience led to the definition of a simple criterion for visual classification of blooms, that can be used by trained lifeguards and technicians to take rapid on-site decisions on beach management. The simple and low cost approach is broadly applicable to risk assessment and risk management in developing countries. PMID:23220602
Guassora, Ann Dorrit; Nielsen, Søren Beck; Reventlow, Susanne
2015-01-01
Objective. The aim of this study is to analyse the interaction between patients and GPs in preventive consultations with an emphasis on how patients answer GPs’ questions about lifestyle, and the conditions these answers impose on the process of establishing agreement about lifestyle as a problem or not. Design. Six general practitioners (GPs) video-recorded 15 annual preventive consultations. From these, 32 excerpts of discussions about lifestyle were analysed using conversation analysis (CA). Results. GPs used an interview format to assess risk in patients’ lifestyles. In some cases patients adhered to this format and answered the GPs’ questions, but in many cases patients gave what we have termed “anticipatory answers”. These answers indicate that the patients anticipate a response from their GPs that would highlight problems with their lifestyle. Typically, in an anticipatory answer, patients bypass the interview format to give their own evaluation of their lifestyle and GPs accept this evaluation. In cases of “no-problem” answers from patients, GPs usually encouraged patients by adding support for current habits. Conclusion. Patients anticipated that GPs might assess their lifestyles as problematic and they incorporated this possibility into their responses. They thereby controlled the definition of their lifestyle as a problem or not. GPs generally did not use the information provided in these answers as a resource for further discussion, but rather relied on standard interview procedures. Staying within the patients’ frame of reference and using the patients’ anticipatory answers might provide GPs with a better point of departure for discussion regarding lifestyle. PMID:26467342
Techniques of Problem Solving.
ERIC Educational Resources Information Center
Krantz, Steven G.
The purpose of this book is to teach the basic principles of problem solving in both mathematical and non-mathematical problems. The major components of the book consist of learning to translate verbal discussion into analytical data, learning problem solving methods for attacking collections of analytical questions or data, and building a…
ERIC Educational Resources Information Center
Pappas, Marjorie L.
1995-01-01
Discusses analytical searching, a process that enables searchers of electronic resources to develop a planned strategy by combining words or phrases with Boolean operators. Defines simple and complex searching, and describes search strategies developed with Boolean logic and truncation. Provides guidelines for teaching students analytical…
ERIC Educational Resources Information Center
Barry, Tammy D.; Lochman, John E.; Fite, Paula J.; Wells, Karen C.; Colder, Craig R.
2012-01-01
The current study utilized a longitudinal design to examine the effects of neighborhood and parenting on 120 at-risk children's academic and aggressive outcomes, concurrently and at two later timepoints during the transition to middle school. Random effects regression models were estimated to examine whether neighborhood characteristics and harsh…
ERIC Educational Resources Information Center
Fischer, Benedikt; Dawe, Meghan; Mcguire, Fraser; Shuper, Paul A; Jones, Wayne; Rudzinski, Katherine; Rehm, Jurgen
2012-01-01
Aims: Assess key cannabis use, risk and outcome characteristics among high-frequency cannabis users within a university student sample in Toronto, Canada. Methods: N = 134 active universities students (ages of 18-28) using cannabis at least three times per week were recruited by mass advertisement, telephone-screened and anonymously assessed by an…
ERIC Educational Resources Information Center
de Koning, Bjorn B.; Loyens, Sofie M. M.; Rikers, Remy M. J. P.; Smeets, Guus; van der Molen, Henk T.
2012-01-01
This study investigated the simultaneous impact of demographic, personality, intelligence, and (prior) study performance factors on students' academic achievement in a three-year academic problem-based psychology program. Information regarding students' gender, age, nationality, pre-university education, high school grades, Big Five personality…
ERIC Educational Resources Information Center
Sen, Bisakha
2010-01-01
Objective: To examine the association between frequency of family dinners (FFD) and selected problem behaviors for adolescents after adjusting for family connectedness, parental awareness, other family activities, and other potentially confounding factors. Methods: Data are drawn from the National Longitudinal Survey of Youth, 1997. The primary…
Analytical multikinks in smooth potentials
NASA Astrophysics Data System (ADS)
de Brito, G. P.; Correa, R. A. C.; de Souza Dutra, A.
2014-03-01
In this work we present an approach that can be systematically used to construct nonlinear systems possessing analytical multikink profile configurations. In contrast with previous approaches to the problem, we are able to do it by using field potentials that are considerably smoother than the ones of the doubly quadratic family of potentials. This is done without losing the capacity of writing exact analytical solutions. The resulting field configurations can be applied to the study of problems from condensed matter to braneworld scenarios.
Advances in analytical chemistry
NASA Technical Reports Server (NTRS)
Arendale, W. F.; Congo, Richard T.; Nielsen, Bruce J.
1991-01-01
Implementation of computer programs based on multivariate statistical algorithms makes possible obtaining reliable information from long data vectors that contain large amounts of extraneous information, for example, noise and/or analytes that we do not wish to control. Three examples are described. Each of these applications requires the use of techniques characteristic of modern analytical chemistry. The first example, using a quantitative or analytical model, describes the determination of the acid dissociation constant for 2,2'-pyridyl thiophene using archived data. The second example describes an investigation to determine the active biocidal species of iodine in aqueous solutions. The third example is taken from a research program directed toward advanced fiber-optic chemical sensors. The second and third examples require heuristic or empirical models.
ERIC Educational Resources Information Center
Novak, Elena
2012-01-01
The study explored instructional benefits of a storyline gaming characteristic (GC) on learning effectiveness, efficiency, and engagement with the use of an online instructional simulation for graduate students in an introductory statistics course. In addition, the study focused on examining the effects of a storyline GC on specific learning…
NASA Astrophysics Data System (ADS)
Mazumdar, Kaushik; Pathak, Gyanesh Kumar; Ghosal, Aniruddha
2016-09-01
In present analysis initially authors have studied the variation of mobility with lattice temperature in Nitride based superlattice MOSFETs and have compared the results with temperature dependent measured mobility of two dimensional electrons in AlGaN/GaN superlattice structure. Based on these mobilities a superlattice MOSFET is designed in which static characteristics following different scattering mechanisms are discussed.
Shevyrin, Vadim; Melkozerov, Vladimir; Nevero, Alexander; Eltsov, Oleg; Morzherin, Yuri; Shafran, Yuri
2014-09-01
By means of gas chromatography with mass spectrometry detection (GC-MS), including high resolution mass spectrometry (GC-HRMS) together with ultra-high performance liquid chromatography in combination with high resolution tandem mass spectrometry (UHPLC-HRMS), nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infrared spectroscopy (FT-IR), structure of novel synthetic cannabinoids, namely, 1-(5-fluoropentyl)-1H-indazol-3-yl(naphthalen-1-yl)methanone, naphthalen-1-yl(1-pentyl-1H-benzo[d]imidazol-2-yl)methanone and 1-(5-fluoropentyl)-1H-benzo[d]imidazol-2-yl(naphthalen-1-yl)methanone was established. Analytical data obtained in the paper enable reliable identification of these compounds during qualitative analysis of seizures, including smoke mixtures. PMID:25036783
Analytic continuation as a bridge between continuum and bound states
NASA Astrophysics Data System (ADS)
Blokhintsev, Leonid; Savin, Dmitry
2015-05-01
The problem of obtaining characteristics of bound nuclear states from continuum states data is discussed. It is shown that the ambiguities due to the existence of phase-equivalent potentials can be resolved by using the analytic properties of scattering amplitudes. The methods of determination of asymptotic normalization coefficients and vertex constants are considered. The asymptotic normalization coefficients for 6Li in the α + d channel are found by analytic continuation of the two-channel effective range expansion. The account of inelastic channels within the effective range approach is discussed.
Lewis, D.W. . Dept. of Geology); McConchie, D.M. . Centre for Coastal Management)
1994-01-01
Both a self instruction manual and a cookbook'' guide to field and laboratory analytical procedures, this book provides an essential reference for non-specialists. With a minimum of mathematics and virtually no theory, it introduces practitioners to easy, inexpensive options for sample collection and preparation, data acquisition, analytic protocols, result interpretation and verification techniques. This step-by-step guide considers the advantages and limitations of different procedures, discusses safety and troubleshooting, and explains support skills like mapping, photography and report writing. It also offers managers, off-site engineers and others using sediments data a quick course in commissioning studies and making the most of the reports. This manual will answer the growing needs of practitioners in the field, either alone or accompanied by Practical Sedimentology, which surveys the science of sedimentology and provides a basic overview of the principles behind the applications.
Cohen-Kettenis, Peggy T; Owen, Allison; Kaijser, Vanessa G; Bradley, Susan J; Zucker, Kenneth J
2003-02-01
This study examined demographic characteristics, social competence, and behavior problems in clinic-referred children with gender identity problems in Toronto, Canada (N = 358), and Utrecht, The Netherlands (N = 130). The Toronto sample was, on average, about a year younger than the Utrecht sample at referral, had a higher percentage of boys, had a higher mean IQ, and was less likely to be living with both parents. On the Child Behavior Checklist (CBCL), both groups showed, on average, clinical range scores in both social competence and behavior problems. A CBCL-derived measure of poor peer relations showed that boys in both clinics had worse ratings than did the girls. A multiple regression analysis showed that poor peer relations were the strongest predictor of behavior problems in both samples. This study-the first cross-national, cross-clinic comparative analysis of children with gender identity disorder-found far more similarities than differences in both social competence and behavior problems. The most salient demographic difference was age at referral. Cross-national differences in factors that might influence referral patterns are discussed. PMID:12597698
NASA Astrophysics Data System (ADS)
Emanuel, Ryan E.; Buckley, John J.; Caldwell, Peter V.; McNulty, Steven G.; Sun, Ge
2015-12-01
Interbasin water transfers are globally important water management strategies, yet little is known about their role in the hydrologic cycle at regional and continental scales. Specifically, there is a dearth of centralized information on transfer locations and characteristics, and few analyses place transfers into a relevant hydrological context. We assessed hydrological characteristics of interbasin transfers (IBTs) in the conterminous US using a nationwide inventory of transfers together with historical climate data and hydrological modeling. Supplying and receiving drainage basins share similar hydroclimatological conditions, suggesting that climatological drivers of water shortages in receiving basins likely have similar effects on supplying basins. This result calls into question the effectiveness of transfers as a strategy to mitigate climate-driven water shortages, as the water shortage may be displaced but not resolved. We also identified hydrologically advantageous and disadvantageous IBTs by comparing the water balances of supplying and receiving basins. Transfer magnitudes did not vary between the two categories, confirming that factors driving individual IBTs, such as patterns of human water demand or engineering constraints, also influence the continental-scale distribution of transfers. Some IBTs impact streamflow for hundreds of kilometers downstream. Transfer magnitude, hydroclimate and organization of downstream river networks mediate downstream impacts, and these impacts have the potential to expand downstream nonlinearly during years of drought. This work sheds new light on IBTs and emphasizes the need for updated inventories and analyses that place IBTs in an appropriate hydrological context.
Cooley, Richard L.
1992-01-01
MODFE, a modular finite-element model for simulating steady- or unsteady-state, area1 or axisymmetric flow of ground water in a heterogeneous anisotropic aquifer is documented in a three-part series of reports. In this report, part 2, the finite-element equations are derived by minimizing a functional of the difference between the true and approximate hydraulic head, which produces equations that are equivalent to those obtained by either classical variational or Galerkin techniques. Spatial finite elements are triangular with linear basis functions, and temporal finite elements are one dimensional with linear basis functions. Physical processes that can be represented by the model include (1) confined flow, unconfined flow (using the Dupuit approximation), or a combination of both; (2) leakage through either rigid or elastic confining units; (3) specified recharge or discharge at points, along lines, or areally; (4) flow across specified-flow, specified-head, or head-dependent boundaries; (5) decrease of aquifer thickness to zero under extreme water-table decline and increase of aquifer thickness from zero as the water table rises; and (6) head-dependent fluxes from springs, drainage wells, leakage across riverbeds or confining units combined with aquifer dewatering, and evapotranspiration. The matrix equations produced by the finite-element method are solved by the direct symmetric-Doolittle method or the iterative modified incomplete-Cholesky conjugate-gradient method. The direct method can be efficient for small- to medium-sized problems (less than about 500 nodes), and the iterative method is generally more efficient for larger-sized problems. Comparison of finite-element solutions with analytical solutions for five example problems demonstrates that the finite-element model can yield accurate solutions to ground-water flow problems.
Silva, Nathanael de Oliveira E; Ronsoni, Marcelo Fernando; Colombo, Bruno da Silveira; Corrêa, Carina Gabriela; Hatanaka, Simone Aiko; Canalli, Maria Heloisa Büsi da Silva; Schiavon, Leonardo de Lucca; Narciso-Schiavon, Janaína Luz
2016-04-01
Objective Thyroid disease affects 6.6% of the general population. The liver is fundamental in metabolizing thyroid hormones, and hepatocytes are often affected in thyroid disease. We aimed to compare clinical and laboratory parameters among thyroid disease patients with alanine aminotransferase (ALT) levels above vs. below the upper tertile. Subjects and methods A retrospective cross-sectional analytical study was conducted in the endocrinology clinic at Polydoro Ernani de São Thiago University Hospital. Patients with thyroid disease between August 2012 and January 2014 were included in the study. Clinical and laboratory parameters were collected from medical records. Results One hundred patients were included, of which 14.0% were male, with a mean age of 49.1 ± 14.4 years. ALT levels ranged from 9 to 90 U/L, and the ALT upper tertile was defined as 0,64 times the upper normal limit (xUNL). Patients with ALT levels above the upper tertile exhibited a higher proportion of systemic arterial hypertension (SAH), a higher mean abdominal circumference and a higher frequency of elevated TSH levels than did patients with ALT levels below the upper tertile. In multivariate analysis, ALT ≥ 0.64 (xUNL) was independently associated with abdominal circumference (odds ratio [OR] = 0.087, 95% confidence interval [CI] 0012-0167, P = 0.022). ALT (xUNL) correlated positively with total cholesterol (r = 0.213, P = 0.042). Conclusions In patients with thyroid diseases, it was observed that those with ALT above the upper tertile are associated with abdominal circumference and ALT levels correlate with total cholesterol. PMID:26331222
ERIC Educational Resources Information Center
Munoz-Martinez, Amanda; Novoa-Gomez, Monica; Gutierrez, Rochy Vargas
2012-01-01
Functional Analytic Psychotherapy (FAP) has been making an important rise in Ibero-America in recent years. This paper presents a review of different contributions, problems and some proposals. Three principal topics are reviewed: (a) general characteristics and theoretical bases of FAP, (b) the uses of FAP and its relationship with other…
Challenges for Visual Analytics
Thomas, James J.; Kielman, Joseph
2009-09-23
Visual analytics has seen unprecedented growth in its first five years of mainstream existence. Great progress has been made in a short time, yet great challenges must be met in the next decade to provide new technologies that will be widely accepted by societies throughout the world. This paper sets the stage for some of those challenges in an effort to provide the stimulus for the research, both basic and applied, to address and exceed the envisioned potential for visual analytics technologies. We start with a brief summary of the initial challenges, followed by a discussion of the initial driving domains and applications, as well as additional applications and domains that have been a part of recent rapid expansion of visual analytics usage. We look at the common characteristics of several tools illustrating emerging visual analytics technologies, and conclude with the top ten challenges for the field of study. We encourage feedback and collaborative participation by members of the research community, the wide array of user communities, and private industry.
NASA Astrophysics Data System (ADS)
Hamida, Youcef
Metal Organic Frameworks (MOFs) exhibit many excellent physical properties including magnetic properties for potential applications in devices. More importantly for the subject of this thesis, MOFs are ideal for the realization of low dimensional magnetism because of the large selection of ligands connecting magnetic centers in making the framework. The materials studied in this thesis include ten magnetic MOFs of the form M(L1)(L2) [M = Cu, Ni, Co, Fe, Mn; L1 = NDC, bpdc, BDC, BODC, N3; L2 = DMF, H2O, TED, bpy]. Polycrystalline powder samples as well as single crystal samples were synthesized. Their crystal structures were determined, and their magnetic and thermodynamic properties were measured and analyzed. Eight of these materials were characterized as 1D magnets and two as 3D magnets. In the 1D case it is found that above Tm [the temperature at which the magnetic susceptibility chi(T) has a peak] the magnetic behavior of MOFs (S ≥ 1) can be well described with the Classical Fisher Model (CFM). Near and below TC the spins take a more definite orientation than allowed for in the CFM and hence the Ising Model (IM) was used for fitting. Both CFM and IM yield fairly consistent intrachain couplings ( J) when applied in their appropriate temperature region. To estimate the interchain exchange (J'), the susceptibility for a magnetic chain in the mean field of neighboring chains is used. In all cases, as expected, the ratio of J to J' was less than 10%. The special case of Cu(N3)2bpy ( S = ½) was analyzed with the spin ½ IM. Although the specific heat data (Ctotal) for most of the 1D MOFs showed no clear phase transition, a low temperature fit to the electron-phonon specific heats yielded apparent heavy fermion-like gamma values on the order of several hundred mJ/mol K2. The lattice specific heat (Clattice) was estimated using a Debye-Einstein hybrid model. Subtracting Clattice from Ctotal, magnetic specific heat ( CM) with a broad peak characteristic of low
GOETZINGER, Katherine R.; SINGLA, Ashima; GERKOWICZ, Sabrina; DICKE, Jeffrey M.; GRAY, Diana L.; ODIBO, Anthony O.
2011-01-01
Objective To determine if a simplified model for predicting pre-eclampsia can be developed by combining first trimester serum analytes, PAPP-A and free β-hCG, and maternal characteristics. Methods A retrospective cohort study of patients seen for first-trimester aneuploidy screening from 2003–2009. The 5th, 10th, 90th and 95th percentiles for the analyte-MoMs for our population were determined and evaluated for association with pre-eclampsia. Univariate and backward stepwise logistic regression analyses were performed and the area under the ROC curves (AUC) used to determine the best models for predicting pre-eclampsia. Results Among 4,020 women meeting the inclusion criteria, outcome data was available for 3,716 (93%). There were 293 cases of pre-eclampsia. The final model identified a history of pre-gestational diabetes (aOR 2.6, 95% CI 1.7–3.9), chronic hypertension (aOR 2.6, 95% CI 1.7–3.9), maternal BMI >25 (aOR 2.5, 95% CI 1.9–3.4), African American race (aOR 1.8, 95% CI 1.3–2.6), and PAPP-A MoM <10th percentile (aOR 1.6, 95% CI 1.1–2.4) to be significant predictors of pre-eclampsia. (AUC= 0.70, 95% CI 0.65–0.72) Conclusion Low first-trimester PAPP-A levels are associated with the development of pre-eclampsia; however, the model was only modestly efficient in its predictive ability. PMID:20936638
Davenport, Thomas H
2006-01-01
We all know the power of the killer app. It's not just a support tool; it's a strategic weapon. Companies questing for killer apps generally focus all their firepower on the one area that promises to create the greatest competitive advantage. But a new breed of organization has upped the stakes: Amazon, Harrah's, Capital One, and the Boston Red Sox have all dominated their fields by deploying industrial-strength analytics across a wide variety of activities. At a time when firms in many industries offer similar products and use comparable technologies, business processes are among the few remaining points of differentiation--and analytics competitors wring every last drop of value from those processes. Employees hired for their expertise with numbers or trained to recognize their importance are armed with the best evidence and the best quantitative tools. As a result, they make the best decisions. In companies that compete on analytics, senior executives make it clear--from the top down--that analytics is central to strategy. Such organizations launch multiple initiatives involving complex data and statistical analysis, and quantitative activity is managed atthe enterprise (not departmental) level. In this article, professor Thomas H. Davenport lays out the characteristics and practices of these statistical masters and describes some of the very substantial changes other companies must undergo in order to compete on quantitative turf. As one would expect, the transformation requires a significant investment in technology, the accumulation of massive stores of data, and the formulation of company-wide strategies for managing the data. But, at least as important, it also requires executives' vocal, unswerving commitment and willingness to change the way employees think, work, and are treated. PMID:16447373
Gustafsson, Annika
2010-01-01
The primary aim of this thesis was to study dental fear, personal characteristics and psychosocial concomitants in relation to dental behaviour management problems (DBMP) and dental attendance. The study sample consisted of children (8-12 yrs) and adolescents (13-19 yrs) referred to the Specialized Paediatric Dental Clinic because of DBMP. They were compared to a reference group of same aged dental patients in ordinary dental care. A methodological study explored the Dental Subscale of the Children's Fear Survey Schedule (CFSS-DS) in terms of agreement between self and parental ratings and age- and gender-differentiated cut-off scores as compared to the commonly used. Baseline data on children's and adolescents' dental fear, psychosocial situation and everyday life, and personal characteristics were analysed according to a variable-based approach using logistic regression analyses and tree-based modelling of group differences. From the frequency of missed or/and cancelled appointments or interruption of dental treatment the group of referred children was separated into two groups (non-attendees vs. attendees). The differences between the groups were analysed using logistic regression analyses and tree-based modelling. It was found that children and adolescents referred because of DBMP differ in several ways from children and adolescents in ordinary dental care. These differences concerns dental fear, emotional and behavioural problems and temperamental aspects, as well as psychosocial concomitants. The results indicated an overall more negative and complex picture for the children and adolescents referred because of DBMP. The occurrence of single-parent families, child-parent separations, and professional support actions were clearly more frequent among patients referred because of DBMP. Dental fear was the only variable with consistent discriminatory capacity for DBMP through all age and gender subgroups. Aspects of anxiety, temperament, and behavioural symptoms
Analytical solutions of moisture flow equations and their numerical evaluation
Gibbs, A.G.
1981-04-01
The role of analytical solutions of idealized moisture flow problems is discussed. Some different formulations of the moisture flow problem are reviewed. A number of different analytical solutions are summarized, including the case of idealized coupled moisture and heat flow. The evaluation of special functions which commonly arise in analytical solutions is discussed, including some pitfalls in the evaluation of expressions involving combinations of special functions. Finally, perturbation theory methods are summarized which can be used to obtain good approximate analytical solutions to problems which are too complicated to solve exactly, but which are close to an analytically solvable problem.
Fröberg, Frida; Rosendahl, Ingvar K; Abbott, Max; Romild, Ulla; Tengström, Anders; Hallqvist, Johan
2015-09-01
We aimed to estimate the incidence of a first episode of problem gambling among Swedish 16-24 year-olds by demographic and socio-economic characteristics, and to compare the incidence between 16-24 and 25-44 year-olds, and between young women and men. Other aims were to estimate the proportions of recovery and incidence in recurrent problem gambling, and prevalence of problem gambling among 16-44 year-olds in Sweden. We selected 4,358 participants aged 16-44 from the nationally representative Swedish Longitudinal Gambling Study in 2008/2009 and 2009/2010. The primary outcome measure was a first episode of problem gambling during 12 months before the follow-up as measured by the Problem Gambling Severity Index among participants without a history of problem gambling at baseline. The incidence proportion of a first episode of problem gambling among 16-24 year-olds was 2.26% (95% confidence interval 1.52-3.36); three times lower among females (1.14; 0.42-3.07%) than males (3.32; 2.19-5.01%). Young age and household financial problems were associated with first episode problem gambling among young women. Among 25-44 year-olds, the incidence proportion of a first episode of problem gambling was 0.81% (0.41-1.56). Recovery from problem gambling was high, in particular among females. Individual transitions from problem gambling to recovery and to recurrent problem gambling, between baseline and follow-up, were common regardless of age. This study adds further evidence to research suggesting that there is a high mobility in and out of problem gambling over time on an individual level. The high incidence of first episode problem gambling among youth in Sweden stresses the importance of prevention of problem gambling at an early age. PMID:24590609
Analytical Chemistry Division's sample transaction system
Stanton, J.S.; Tilson, P.A.
1980-10-01
The Analytical Chemistry Division uses the DECsystem-10 computer for a wide range of tasks: sample management, timekeeping, quality assurance, and data calculation. This document describes the features and operating characteristics of many of the computer programs used by the Division. The descriptions are divided into chapters which cover all of the information about one aspect of the Analytical Chemistry Division's computer processing.
NASA Astrophysics Data System (ADS)
Xiao, Fengchao; Murano, Kimitoshi; Kami, Yoshio
In this paper the time-domain analysis of two parallel traces is investigated. First, the telegrapher's equations for transmission line are applied to the parallel traces on printed circuit board (PCB), and are solved by using the mode decomposition technique. The time-domain solutions are then obtained by using the inverse Laplace transform. Although the Fourier-transform technique is also applicable for this problem, the solution is given numerically. Contrarily, the inverse Laplace transform successfully leads to an analytical expression for the transmission characteristics. The analytical expression is represented by series, which clearly explains the coupling mechanism. The analytical expression for the fundamental section of a meander delay line is investigated in detail. The analytical solution is validated by measurements, and the characteristics of the distortions in the output waveforms of meander delay lines due to the crosstalk are also investigated.
ERIC Educational Resources Information Center
Oblinger, Diana G.
2012-01-01
Talk about analytics seems to be everywhere. Everyone is talking about analytics. Yet even with all the talk, many in higher education have questions about--and objections to--using analytics in colleges and universities. In this article, the author explores the use of analytics in, and all around, higher education. (Contains 1 note.)
ERIC Educational Resources Information Center
MacNeill, Sheila; Campbell, Lorna M.; Hawksey, Martin
2014-01-01
This article presents an overview of the development and use of analytics in the context of education. Using Buckingham Shum's three levels of analytics, the authors present a critical analysis of current developments in the domain of learning analytics, and contrast the potential value of analytics research and development with real world…
NASA Astrophysics Data System (ADS)
Cline, D.
2002-12-01
provide improved snow information to the government, academia, and the public. The model provides an exciting new look at snow pack dynamics across the country, but it is still just a model, and requires appropriate snow observations for evaluation and assimilation to correct model states. The characteristics of snow observations available in the U.S. has proven to be a severe limitation in this regard. The NASA Cold Land Processes Field Experiment, conducted earlier this year, has provided new research data sets that have already helped quantify the problem of using point (ground) observations of snow in spatially distributed snow models. Results indicate that although the snow model operates at high spatial resolution for improved physical representation of processes, assimilation of point observations of snow states is limited to gross regional corrections, where a sufficient number of point observations exist to reveal a pattern of model errors. Analyses of these data underscore the need for advanced remote sensing measurements of process-oriented snow characteristics, at resolutions commensurate with modern hydrologic models, to reliably evaluate and correct the models on a spatially distributed basis.
Schauber, Stefan K; Hecht, Martin; Nouns, Zineb M; Kuhlmey, Adelheid; Dettmer, Susanne
2015-10-01
In medical education, the effect of the educational environment on student achievement has primarily been investigated in comparisons between traditional and problem-based learning (PBL) curricula. As many of these studies have reached no clear conclusions on the superiority of the PBL approach, the effect of curricular reform on student performance remains an issue. We employed a theoretical framework that integrates antecedents of student achievement from various psychosocial domains to examine how students interact with their curricular environment. In a longitudinal study with N = 1,646 participants, we assessed students in a traditional and a PBL-centered curriculum. The measures administered included students' perception of the learning environment, self-efficacy beliefs, positive study-related affect, social support, indicators of self-regulated learning, and academic achievement assessed through progress tests. We compared the relations between these characteristics in the two curricular environments. The results are two-fold. First, substantial relations of various psychosocial domains and their associations with achievement were identified. Second, our analyses indicated that there are no substantial differences between traditional and PBL-based curricula concerning the relational structure of psychosocial variables and achievement. Drawing definite conclusions on the role of curricular-level interventions in the development of student's academic achievement is constrained by the quasi-experimental design as wells as the selection of variables included. However, in the specific context described here, our results may still support the view of student activity as the key ingredient in the acquisition of achievement and performance. PMID:25616720
Collaborative Analytical Toolbox version 1.0
Energy Science and Technology Software Center (ESTSC)
2008-08-21
The purpose of the Collaborative Analytical Toolbox (CAT) is to provide a comprehensive, enabling, collaborative problem solving environment that enables users to more effectively apply and improve their analytical and problem solving capabilities. CAT is a software framework for integrating other tools and data sources. It includes a set of core services for collaboration and information exploration and analysis, and a framework that facilitates quickly integrating new ideas, techniques, and tools with existing data sources.
Big Data Analytics in Healthcare
Belle, Ashwin; Thiagarajan, Raghuram; Soroushmehr, S. M. Reza; Navidi, Fatemeh; Beard, Daniel A.; Najarian, Kayvan
2015-01-01
The rapidly expanding field of big data analytics has started to play a pivotal role in the evolution of healthcare practices and research. It has provided tools to accumulate, manage, analyze, and assimilate large volumes of disparate, structured, and unstructured data produced by current healthcare systems. Big data analytics has been recently applied towards aiding the process of care delivery and disease exploration. However, the adoption rate and research development in this space is still hindered by some fundamental problems inherent within the big data paradigm. In this paper, we discuss some of these major challenges with a focus on three upcoming and promising areas of medical research: image, signal, and genomics based analytics. Recent research which targets utilization of large volumes of medical data while combining multimodal data from disparate sources is discussed. Potential areas of research within this field which have the ability to provide meaningful impact on healthcare delivery are also examined. PMID:26229957
Big Data Analytics in Healthcare.
Belle, Ashwin; Thiagarajan, Raghuram; Soroushmehr, S M Reza; Navidi, Fatemeh; Beard, Daniel A; Najarian, Kayvan
2015-01-01
The rapidly expanding field of big data analytics has started to play a pivotal role in the evolution of healthcare practices and research. It has provided tools to accumulate, manage, analyze, and assimilate large volumes of disparate, structured, and unstructured data produced by current healthcare systems. Big data analytics has been recently applied towards aiding the process of care delivery and disease exploration. However, the adoption rate and research development in this space is still hindered by some fundamental problems inherent within the big data paradigm. In this paper, we discuss some of these major challenges with a focus on three upcoming and promising areas of medical research: image, signal, and genomics based analytics. Recent research which targets utilization of large volumes of medical data while combining multimodal data from disparate sources is discussed. Potential areas of research within this field which have the ability to provide meaningful impact on healthcare delivery are also examined. PMID:26229957
Data Intensive Architecture for Scalable Cyber Analytics
Olsen, Bryan K.; Johnson, John R.; Critchlow, Terence J.
2011-11-15
Cyber analysts are tasked with the identification and mitigation of network exploits and threats. These compromises are difficult to identify due to the characteristics of cyber communication, the volume of traffic, and the duration of possible attack. It is necessary to have analytical tools to help analysts identify anomalies that span seconds, days, and weeks. Unfortunately, providing analytical tools effective access to the volumes of underlying data requires novel architectures, which is often overlooked in operational deployments. Our work is focused on a summary record of communication, called a flow. Flow records are intended to summarize a communication session between a source and a destination, providing a level of aggregation from the base data. Despite this aggregation, many enterprise network perimeter sensors store millions of network flow records per day. The volume of data makes analytics difficult, requiring the development of new techniques to efficiently identify temporal patterns and potential threats. The massive volume makes analytics difficult, but there are other characteristics in the data which compound the problem. Within the billions of records of communication that transact, there are millions of distinct IP addresses involved. Characterizing patterns of entity behavior is very difficult with the vast number of entities that exist in the data. Research has struggled to validate a model for typical network behavior with hopes it will enable the identification of atypical behavior. Complicating matters more, typically analysts are only able to visualize and interact with fractions of data and have the potential to miss long term trends and behaviors. Our analysis approach focuses on aggregate views and visualization techniques to enable flexible and efficient data exploration as well as the capability to view trends over long periods of time. Realizing that interactively exploring summary data allowed analysts to effectively identify
Analytical and Computational Aspects of Collaborative Optimization
NASA Technical Reports Server (NTRS)
Alexandrov, Natalia M.; Lewis, Robert Michael
2000-01-01
Bilevel problem formulations have received considerable attention as an approach to multidisciplinary optimization in engineering. We examine the analytical and computational properties of one such approach, collaborative optimization. The resulting system-level optimization problems suffer from inherent computational difficulties due to the bilevel nature of the method. Most notably, it is impossible to characterize and hence identify solutions of the system-level problems because the standard first-order conditions for solutions of constrained optimization problems do not hold. The analytical features of the system-level problem make it difficult to apply conventional nonlinear programming algorithms. Simple examples illustrate the analysis and the algorithmic consequences for optimization methods. We conclude with additional observations on the practical implications of the analytical and computational properties of collaborative optimization.
Analytical Challenges in Biotechnology.
ERIC Educational Resources Information Center
Glajch, Joseph L.
1986-01-01
Highlights five major analytical areas (electrophoresis, immunoassay, chromatographic separations, protein and DNA sequencing, and molecular structures determination) and discusses how analytical chemistry could further improve these techniques and thereby have a major impact on biotechnology. (JN)
ERIC Educational Resources Information Center
Jitendra, Asha K.; Corroy, Kelly Cozine; Dupuis, Danielle N.
2013-01-01
The purposes of this study were (a) to evaluate differences in arithmetic word problem solving between high and low at-risk students for mathematics difficulties (MD) and (b) to assess the influence of attention, behavior, reading, and socio-economic status (SES) in predicting the word problem solving performance of third-grade students with MD.…
Analyticity without Differentiability
ERIC Educational Resources Information Center
Kirillova, Evgenia; Spindler, Karlheinz
2008-01-01
In this article we derive all salient properties of analytic functions, including the analytic version of the inverse function theorem, using only the most elementary convergence properties of series. Not even the notion of differentiability is required to do so. Instead, analytical arguments are replaced by combinatorial arguments exhibiting…
NASA Technical Reports Server (NTRS)
Ellerbrock, Herman H , Jr; Ziemer, Robert R
1950-01-01
In determining the experimental performance of an air-cooled turbine, the heat-transfer characteristics must be evaluated. The suggested formulas that are required to determine these characteristics are presented. The formulas have a form in which dependent parameters are expressed as unknown functions of independent parameters. Methods of experimenting to determine these functions are suggested. In some cases general heat-transfer discussions that lead to the suggested forms of the formulas are given.
Analytical optical scattering in clouds
NASA Technical Reports Server (NTRS)
Phanord, Dieudonne D.
1989-01-01
An analytical optical model for scattering of light due to lightning by clouds of different geometry is being developed. The self-consistent approach and the equivalent medium concept of Twersky was used to treat the case corresponding to outside illumination. Thus, the resulting multiple scattering problem is transformed with the knowledge of the bulk parameters, into scattering by a single obstacle in isolation. Based on the size parameter of a typical water droplet as compared to the incident wave length, the problem for the single scatterer equivalent to the distribution of cloud particles can be solved either by Mie or Rayleigh scattering theory. The super computing code of Wiscombe can be used immediately to produce results that can be compared to the Monte Carlo computer simulation for outside incidence. A fairly reasonable inverse approach using the solution of the outside illumination case was proposed to model analytically the situation for point sources located inside the thick optical cloud. Its mathematical details are still being investigated. When finished, it will provide scientists an enhanced capability to study more realistic clouds. For testing purposes, the direct approach to the inside illumination of clouds by lightning is under consideration. Presently, an analytical solution for the cubic cloud will soon be obtained. For cylindrical or spherical clouds, preliminary results are needed for scattering by bounded obstacles above or below a penetrable surface interface.
Moran, B
2007-08-08
We present analytic solutions to two test problems that can be used to check the hydrodynamic implementation in computer codes designed to calculate the propagation of shocks in spherically convergent geometry. Our analysis is restricted to fluid materials with constant bulk modulus. In the first problem we present the exact initial acceleration and pressure gradient at the outer surface of a sphere subjected to an exponentially decaying pressure of the form P(t) = P{sub 0}e{sup -at}. We show that finely-zoned hydro-code simulations are in good agreement with our analytic solution. In the second problem we discuss the implosions of incompressible spherical fluid shells and we present the radial pressure profile across the shell thickness. We also discuss a semi-analytic solution to the time-evolution of a nearly spherical shell with arbitrary but small initial 3-dimensional (3-D) perturbations on its inner and outer surfaces.
ERIC Educational Resources Information Center
Satake, Hiroyuki; Yamashita, Hiroshi; Yoshida, Keiko
2004-01-01
We investigated whether the correlates of family psychosocial characteristics among Japanese children with attention-deficit hyperactivity disorder (ADHD) differ according to the comorbid condition of oppositional defiant disorder (ODD) or conduct disorder (CD). Three groups of children (12 ADHD, 15 ADHD + ODD/ CD, and 14 control) were compared on…
Writing analytic element programs in Python.
Bakker, Mark; Kelson, Victor A
2009-01-01
The analytic element method is a mesh-free approach for modeling ground water flow at both the local and the regional scale. With the advent of the Python object-oriented programming language, it has become relatively easy to write analytic element programs. In this article, an introduction is given of the basic principles of the analytic element method and of the Python programming language. A simple, yet flexible, object-oriented design is presented for analytic element codes using multiple inheritance. New types of analytic elements may be added without the need for any changes in the existing part of the code. The presented code may be used to model flow to wells (with either a specified discharge or drawdown) and streams (with a specified head). The code may be extended by any hydrogeologist with a healthy appetite for writing computer code to solve more complicated ground water flow problems. PMID:19473273
Analytical methods for solving the Boltzmann equation
NASA Astrophysics Data System (ADS)
Struminskii, V. V.
The principal analytical methods for solving the Boltzmann equation are reviewed, and a very general solution is proposed. The method makes it possible to obtain a solution to the Cauchy problem for the nonlinear Boltzmann equation and thus determine the applicability regions for the various analytical methods. The method proposed here also makes it possible to demonstrate that Hilbert's theorem of macroscopic causality does not apply and Hilbert's paradox does not exist.
Education: Holistic Approach Urged for Teaching Analytical Chemistry.
ERIC Educational Resources Information Center
Chemical and Engineering News, 1983
1983-01-01
Recommends teaching analytical chemistry using an approach that emphasizes the problem as well as the sample. This problem-solving approach would complement and not replace the study of fundamental and applied aspects of chemical determinations. Also considers four components of analytical chemistry: analysis, research, development, and education.…
ERIC Educational Resources Information Center
Waaland, Torbjorn
2013-01-01
Purpose: The purpose of this paper is to study the influence of problem-solving tasks on mentoring received, peer mentoring and mentoring provided. Design/methodology/approach: This cross-sectional survey was based on a questionnaire that was sent to a total of 435 employees from 29 pre-schools in Norway. A total of 284 responses were returned, a…
NASA Technical Reports Server (NTRS)
Kozdoba, L. A.; Krivoshei, F. A.
1985-01-01
The solution of the inverse problem of nonsteady heat conduction is discussed, based on finding the coefficient of the heat conduction and the coefficient of specific volumetric heat capacity. These findings are included in the equation used for the electrical model of this phenomenon.
Science Update: Analytical Chemistry.
ERIC Educational Resources Information Center
Worthy, Ward
1980-01-01
Briefly discusses new instrumentation in the field of analytical chemistry. Advances in liquid chromatography, photoacoustic spectroscopy, the use of lasers, and mass spectrometry are also discussed. (CS)
Analytical Chemistry in Industry.
ERIC Educational Resources Information Center
Kaiser, Mary A.; Ullman, Alan H.
1988-01-01
Clarifies the roles of a practicing analytical chemist in industry: quality control, methods and technique development, troubleshooting, research, and chemical analysis. Lists criteria for success in industry. (ML)
Waste minimization in analytical methods
Green, D.W.; Smith, L.L.; Crain, J.S.; Boparai, A.S.; Kiely, J.T.; Yaeger, J.S. Schilling, J.B.
1995-05-01
The US Department of Energy (DOE) will require a large number of waste characterizations over a multi-year period to accomplish the Department`s goals in environmental restoration and waste management. Estimates vary, but two million analyses annually are expected. The waste generated by the analytical procedures used for characterizations is a significant source of new DOE waste. Success in reducing the volume of secondary waste and the costs of handling this waste would significantly decrease the overall cost of this DOE program. Selection of appropriate analytical methods depends on the intended use of the resultant data. It is not always necessary to use a high-powered analytical method, typically at higher cost, to obtain data needed to make decisions about waste management. Indeed, for samples taken from some heterogeneous systems, the meaning of high accuracy becomes clouded if the data generated are intended to measure a property of this system. Among the factors to be considered in selecting the analytical method are the lower limit of detection, accuracy, turnaround time, cost, reproducibility (precision), interferences, and simplicity. Occasionally, there must be tradeoffs among these factors to achieve the multiple goals of a characterization program. The purpose of the work described here is to add waste minimization to the list of characteristics to be considered. In this paper the authors present results of modifying analytical methods for waste characterization to reduce both the cost of analysis and volume of secondary wastes. Although tradeoffs may be required to minimize waste while still generating data of acceptable quality for the decision-making process, they have data demonstrating that wastes can be reduced in some cases without sacrificing accuracy or precision.
Analytical investigation of curved steel girder behaviour
NASA Astrophysics Data System (ADS)
Simpson, Michael Donald
Horizontally curved bridges meet an increasing demand for complex highway geometries in congested urban areas. A popular type of curved bridge consists of steel I-girders interconnected by cross-frames and a composite concrete deck slab. Prior to hardening of the concrete deck each I-girder is susceptible to a lateral torsional buckling-type failure. Unlike a straight I-girder, a curved I-girder resists major components of stress resulting from strong axis bending, weak axis bending and warping. The combination of these stresses reduce the available strength of a curved girder versus that of an equivalent straight girder. Experiments demonstrating the ultimate strength characteristics of curved girders are few in number. Of the available experimental research, few studies have used full scale-tests and boundary conditions indicative of those found in an actual bridge structure. Unlike straight girders, curved girders are characterized by nonlinear out-of-plane deformations which, depending upon the magnitude of curvature, may occur at very low load levels. Because of the inherent nonlinear behaviour, some have questioned the application of the term lateral torsional buckling to curved girders; rather curved girders behave in a manner consistent with a deflection-amplification problem. Even with the advent of sophisticated analytical techniques, there is a glaring void in the documented literature regarding calibration of these techniques with known experimental curved girder behaviour. Presented here is an analytical study of the nonlinear modelling of curved steel girders and bridges. This is accomplished by incorporating large deflection and nonlinear material behaviour into three dimensional finite element models generated using the program ANSYS. Emphasis is placed on the calibration of the finite method with known experimental ultimate strength data. It is demonstrated that accurate predictions of load deformation and ultimate strength are attainable via the
Analytical Ultrasonics in Materials Research and Testing
NASA Technical Reports Server (NTRS)
Vary, A.
1986-01-01
Research results in analytical ultrasonics for characterizing structural materials from metals and ceramics to composites are presented. General topics covered by the conference included: status and advances in analytical ultrasonics for characterizing material microstructures and mechanical properties; status and prospects for ultrasonic measurements of microdamage, degradation, and underlying morphological factors; status and problems in precision measurements of frequency-dependent velocity and attenuation for materials analysis; procedures and requirements for automated, digital signal acquisition, processing, analysis, and interpretation; incentives for analytical ultrasonics in materials research and materials processing, testing, and inspection; and examples of progress in ultrasonics for interrelating microstructure, mechanical properites, and dynamic response.
NASA Technical Reports Server (NTRS)
Ellerbrock, Herman H , Jr
1950-01-01
In the determination of the performance of an air-cooled turbine, the cooling-air-flow characteristics between the root and the tip of the blades must be evaluated. The methods, which must be verified and the unknown functions evaluated, that are expected to permit the determination of pressure, temperature, and velocity through the blade cooling-air passages from specific investigation are presented.
Technical, analytical and computer support
NASA Technical Reports Server (NTRS)
1972-01-01
The development of a rigorous mathematical model for the design and performance analysis of cylindrical silicon-germanium thermoelectric generators is reported that consists of two parts, a steady-state (static) and a transient (dynamic) part. The material study task involves the definition and implementation of a material study that aims to experimentally characterize the long term behavior of the thermoelectric properties of silicon-germanium alloys as a function of temperature. Analytical and experimental efforts are aimed at the determination of the sublimation characteristics of silicon germanium alloys and the study of sublimation effects on RTG performance. Studies are also performed on a variety of specific topics on thermoelectric energy conversion.
ERIC Educational Resources Information Center
Callis, James B.; And Others
1987-01-01
Discusses process analytical chemistry as a discipline designed to supply quantitative and qualitative information about a chemical process. Encourages academic institutions to examine this field for employment opportunities for students. Describes the five areas of process analytical chemistry, including off-line, at-line, on-line, in-line, and…
Learning Analytics Considered Harmful
ERIC Educational Resources Information Center
Dringus, Laurie P.
2012-01-01
This essay is written to present a prospective stance on how learning analytics, as a core evaluative approach, must help instructors uncover the important trends and evidence of quality learner data in the online course. A critique is presented of strategic and tactical issues of learning analytics. The approach to the critique is taken through…
Not Available
1990-01-01
This 43rd Annual Summer Symposium on Analytical Chemistry was held July 24--27, 1990 at Oak Ridge, TN and contained sessions on the following topics: Fundamentals of Analytical Mass Spectrometry (MS), MS in the National Laboratories, Lasers and Fourier Transform Methods, Future of MS, New Ionization and LC/MS Methods, and an extra session. (WET)
Analytical mass spectrometry. Abstracts
Not Available
1990-12-31
This 43rd Annual Summer Symposium on Analytical Chemistry was held July 24--27, 1990 at Oak Ridge, TN and contained sessions on the following topics: Fundamentals of Analytical Mass Spectrometry (MS), MS in the National Laboratories, Lasers and Fourier Transform Methods, Future of MS, New Ionization and LC/MS Methods, and an extra session. (WET)
ERIC Educational Resources Information Center
Ember, Lois R.
1977-01-01
The procedures utilized by the Association of Official Analytical Chemists (AOAC) to develop, evaluate, and validate analytical methods for the analysis of chemical pollutants are detailed. Methods validated by AOAC are used by the EPA and FDA in their enforcement programs and are granted preferential treatment by the courts. (BT)
ERIC Educational Resources Information Center
Jackson, Brian
2010-01-01
Using a survey of 138 writing programs, I argue that we must be more explicit about what we think students should get out of analysis to make it more likely that students will transfer their analytical skills to different settings. To ensure our students take analytical skills with them at the end of the semester, we must simplify the task we…
Signals: Applying Academic Analytics
ERIC Educational Resources Information Center
Arnold, Kimberly E.
2010-01-01
Academic analytics helps address the public's desire for institutional accountability with regard to student success, given the widespread concern over the cost of higher education and the difficult economic and budgetary conditions prevailing worldwide. Purdue University's Signals project applies the principles of analytics widely used in…
Modern analytical chemistry in the contemporary world
NASA Astrophysics Data System (ADS)
Šíma, Jan
2016-02-01
Students not familiar with chemistry tend to misinterpret analytical chemistry as some kind of the sorcery where analytical chemists working as modern wizards handle magical black boxes able to provide fascinating results. However, this approach is evidently improper and misleading. Therefore, the position of modern analytical chemistry among sciences and in the contemporary world is discussed. Its interdisciplinary character and the necessity of the collaboration between analytical chemists and other experts in order to effectively solve the actual problems of the human society and the environment are emphasized. The importance of the analytical method validation in order to obtain the accurate and precise results is highlighted. The invalid results are not only useless; they can often be even fatal (e.g., in clinical laboratories). The curriculum of analytical chemistry at schools and universities is discussed. It is referred to be much broader than traditional equilibrium chemistry coupled with a simple description of individual analytical methods. Actually, the schooling of analytical chemistry should closely connect theory and practice.
Assessing the Quality of Problems in Problem-Based Learning
ERIC Educational Resources Information Center
Sockalingam, Nachamma; Rotgans, Jerome; Schmidt, Henk
2012-01-01
This study evaluated the construct validity and reliability of a newly devised 32-item problem quality rating scale intended to measure the quality of problems in problem-based learning. The rating scale measured the following five characteristics of problems: the extent to which the problem (1) leads to learning objectives, (2) is familiar, (3)…
Quo vadis, analytical chemistry?
Valcárcel, Miguel
2016-01-01
This paper presents an open, personal, fresh approach to the future of Analytical Chemistry in the context of the deep changes Science and Technology are anticipated to experience. Its main aim is to challenge young analytical chemists because the future of our scientific discipline is in their hands. A description of not completely accurate overall conceptions of our discipline, both past and present, to be avoided is followed by a flexible, integral definition of Analytical Chemistry and its cornerstones (viz., aims and objectives, quality trade-offs, the third basic analytical reference, the information hierarchy, social responsibility, independent research, transfer of knowledge and technology, interfaces to other scientific-technical disciplines, and well-oriented education). Obsolete paradigms, and more accurate general and specific that can be expected to provide the framework for our discipline in the coming years are described. Finally, the three possible responses of analytical chemists to the proposed changes in our discipline are discussed. PMID:26631024
NASA Technical Reports Server (NTRS)
Schmalhofer, Joseph; Faghri, Amir
1993-01-01
The wall and centerline vapor temperatures and heat output are determined experimentally for a low-temperature copper-water heat pipe under uniform circumferential heating and block heating. The time required to reach a vapor temperature of 60 C from an initial ambient temperature of 21 C is determined for both modes of heating. The experimental capillary limit of the heat pipe is compared to the generalized capillary limits for block-heated pipes over a range of vapor temperatures. A three-dimensional numerical model is then developed for determining the temperature, pressure, and velocity distributions in the entire domain of a circumferentially heated and a block-heated pipe. The problem is formulated as a conjugate problem, without the assumption of a uniform vapor temperature. The predictions of the model are found to be in good agreement with the experimental data.
NASA Astrophysics Data System (ADS)
Kunasz, P. B.; Olson, Gordon L.
1988-01-01
The performance of the method of Kunasz and Auer (1988) in the treatment of the non-LTE transfer problem is investigated for a sample of physical models, and comparisons with the direct implicit solutions of Mihalis et al. (1978) are presented. Although the effect of two-dimensionality on performance is found to be minimal, the advantages in accuracy of quadratic over linear interpolation on spatial resolution are found to be significant. The practicality of using approximate operators with nearest-neighbor coupling is compared for the cases of one-dimensional and two-dimensional slabs.
Multiple Solutions Involving Geoboard Problems.
ERIC Educational Resources Information Center
Smith, Lyle R.
1993-01-01
Illustrates various methods to determine the perimeter and area of triangles and polygons formed on the geoboard. Methods utilize algebraic techniques, trigonometry, geometric theorems, and analytic geometry to solve problems and connect a variety of mathematical concepts. (MDH)
Analytic studies in nuclear astrophysics
NASA Astrophysics Data System (ADS)
Pizzochero, Pierre
Five studies are presented in nuclear astrophysics, which deal with different stages of stellar evolution and which use analytic techniques as opposed to numerical ones. Two problems are described in neutrino astrophysics: the solar-neutrino puzzle is analyzed in the framework of the MSW mechanism for the enhancement of neutrino oscillations in matter; and the cooling of neutron stars is studied by calculating the neutrino emissivity from strangeness condensation. Radiative transfer is then examined as applied to SN1987A: its early spectrum and bolometric corrections are calculated by developing an analytic model which can describe both the extended nature of the envelope and the non-LTE state of the radiation field in the scattering-dominated early atmosphere; and a model-independent relation is derived between mass and kinetic energy for the hydrogen envelope of SN1987A, using only direct observations of its luminosity and photospheric velocity. Finally, an analytic approach is presented to relate the softness of the EOS of dense nuclear matter in the core of a supernova, the hydrostatic structure of such core and the initial strength of the shock wave.
Organic materials able to detect analytes
NASA Technical Reports Server (NTRS)
Rose, Aimee (Inventor); Swager, Timothy M. (Inventor); Zhu, Zhengguo (Inventor); Bulovic, Vladimir (Inventor); Madigan, Conor Francis (Inventor)
2012-01-01
The present invention generally relates to polymers with lasing characteristics that allow the polymers to be useful in detecting analytes. In one aspect, the polymer, upon an interaction with an analyte, may exhibit a change in a lasing characteristic that can be determined in some fashion. For example, interaction of an analyte with the polymer may affect the ability of the polymer to reach an excited state that allows stimulated emission of photons to occur, which may be determined, thereby determining the analyte. In another aspect, the polymer, upon interaction with an analyte, may exhibit a change in stimulated emission that is at least 10 times greater with respect to a change in the spontaneous emission of the polymer upon interaction with the analyte. The polymer may be a conjugated polymer in some cases. In one set of embodiments, the polymer includes one or more hydrocarbon side chains, which may be parallel to the polymer backbone in some instances. In another set of embodiments, the polymer may include one or more pendant aromatic rings. In yet another set of embodiments, the polymer may be substantially encapsulated in a hydrocarbon. In still another set of embodiments, the polymer may be substantially resistant to photobleaching. In certain aspects, the polymer may be useful in the detection of explosive agents, such as 2,4,6-trinitrotoluene (TNT) and 2,4-dinitrotoluene (DNT).
Benzodiazepine metabolism: an analytical perspective.
Mandrioli, Roberto; Mercolini, Laura; Raggi, Maria Augusta
2008-10-01
Benzodiazepines are currently among the most frequently prescribed drugs all over the world. They act as anxiolytics, sedatives, hypnotics, amnesics, antiepileptics and muscle relaxants. Despite their common chemical scaffold, these drugs differ in their pharmacokinetic and metabolic properties. In particular, they are biotransformed by different cytochrome P450 isoforms and also by different UDP-glucuronosyltransferase subtypes. The most important studies on the metabolic characteristics of several 1,4-benzodiazepines, carried out from 1998 onwards, are reported and briefly discussed in this review. Moreover, the analytical methods related to these studies are also described and commented upon and their most important characteristics are highlighted. Most methods are based on liquid chromatography, which provides wide applicability and good analytical performance granting high precision, accuracy and feasibility. Mass spectrometry is gaining widespread acceptance, particularly if the matrix is very complex and variable, such as human or animal blood. However, spectrophotometric detection is still used for this purpose and can grant sufficient selectivity and sensitivity when coupled to suitable sample pre-treatment procedures. A monograph is included for each of the following benzodiazepines: alprazolam, bromazepam, brotizolam, clotiazepam, diazepam, etizolam, flunitrazepam, lorazepam, midazolam, oxazepam and triazolam. PMID:18855614
Enzymes in Analytical Chemistry.
ERIC Educational Resources Information Center
Fishman, Myer M.
1980-01-01
Presents tabular information concerning recent research in the field of enzymes in analytic chemistry, with methods, substrate or reaction catalyzed, assay, comments and references listed. The table refers to 128 references. Also listed are 13 general citations. (CS)
Analytical techniques: A compilation
NASA Technical Reports Server (NTRS)
1975-01-01
A compilation, containing articles on a number of analytical techniques for quality control engineers and laboratory workers, is presented. Data cover techniques for testing electronic, mechanical, and optical systems, nondestructive testing techniques, and gas analysis techniques.
Extreme Scale Visual Analytics
Steed, Chad A; Potok, Thomas E; Pullum, Laura L; Ramanathan, Arvind; Shipman, Galen M; Thornton, Peter E
2013-01-01
Given the scale and complexity of today s data, visual analytics is rapidly becoming a necessity rather than an option for comprehensive exploratory analysis. In this paper, we provide an overview of three applications of visual analytics for addressing the challenges of analyzing climate, text streams, and biosurveilance data. These systems feature varying levels of interaction and high performance computing technology integration to permit exploratory analysis of large and complex data of global significance.
Ellouz, Hanen; Feki, Ines; Jeribi, Aref
2013-11-15
In the present paper, we prove that the family of exponentials associated to the eigenvalues of the perturbed operator T(ε) ≔ T{sub 0} + εT{sub 1} + ε{sup 2}T{sub 2} + … + ε{sup k}T{sub k} + … forms a Riesz basis in L{sup 2}(0, T), T > 0, where ε∈C, T{sub 0} is a closed densely defined linear operator on a separable Hilbert space H with domain D(T{sub 0}) having isolated eigenvalues with multiplicity one, while T{sub 1}, T{sub 2}, … are linear operators on H having the same domain D⊃D(T{sub 0}) and satisfying a specific growing inequality. After that, we generalize this result using a H-Lipschitz function. As application, we consider a non-selfadjoint problem deduced from a perturbation method for sound radiation.
Biochemical Applications in the Analytical Chemistry Lab
ERIC Educational Resources Information Center
Strong, Cynthia; Ruttencutter, Jeffrey
2004-01-01
An HPLC and a UV-visible spectrophotometer are identified as instruments that helps to incorporate more biologically-relevant experiments into the course, in order to increase the students understanding of selected biochemistry topics and enhances their ability to apply an analytical approach to biochemical problems. The experiment teaches…
Analytical solutions to constrained hypersonic flight trajectories
NASA Technical Reports Server (NTRS)
Lu, Ping
1992-01-01
The flight trajectory of aerospace vehicles subject to a class of path constraints is considered. The constrained dynamics is shown to be a natural two-time-scale system. Asymptotic analytical solutions are obtained. Problems of trajectory optimization and guidance can be dramatically simplified with these solutions. Applications in trajectory design for an aerospace plane strongly support the theoretical development.
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... it could be a sign of a balance problem. Balance problems can make you feel unsteady or as if ... related injuries, such as hip fracture. Some balance problems are due to problems in the inner ear. ...
... often, it could be a sign of a balance problem. Balance problems can make you feel unsteady or as ... fall-related injuries, such as hip fracture. Some balance problems are due to problems in the inner ...
Laser satellite constellations for strategic defense - an analytic model
Parmentola, J.A.; Milton, A.F.
1987-10-01
Using mainly geometric reasoning, an analytic model is constructed that predicts the required characteristics of an orbiting constellation of laser battle stations, each of which is designed to destroy ballistic missiles during their boost phase. The geometry of the constellation configuration and some general aspects of the coverage problem are discussed. The determination of the absentee ratio falls into two main categories that depend upon whether the Soviet ICBM threat is concentrated at a single location or whether it is distributed as it is now. A point-threat model and a distributive threat model are considered, the determination of the respective kill rates for these models is discussed, and the scaling properties of the laser constellation with respect to a change in the quantitative nature of the two types of ICBM threats are considered.
Insights from a pseudospectral approach to the Elder problem
NASA Astrophysics Data System (ADS)
van Reeuwijk, Maarten; Mathias, Simon A.; Simmons, Craig T.; Ward, James D.
2009-04-01
The aim of this paper is to clarify and circumvent the issue of multiple steady state solutions in the Elder problem. A pseudospectral method is used to avoid numerical error associated with spatial discretization. The pseudospectral method is verified by comparison to an analytical solution at Rayleigh number, Ra = 0, and by reproducing the three stable steady state solutions that are known to exist at Ra = 400. A bifurcation diagram for 0 < Ra < 400, which is free of discretization error, confirms that multiple steady states are indeed an intrinsic characteristic of the Elder problem. The existence of multiple steady states makes the Ra = 400 Elder problem less suitable for benchmarking numerical models. To avoid the multiple steady states, we propose a benchmark at Ra = 60. The results for this Low Rayleigh Number Elder Problem are presented and compared to simulations with the commercial groundwater modeling package FEFLOW. Correspondence between the pseudospectral model and FEFLOW is excellent.
Strehlow, Matthew C; Newberry, Jennifer A; Bills, Corey B; Min, Hyeyoun (Elise); Evensen, Ann E; Leeman, Lawrence; Pirrotta, Elizabeth A; Rao, G V Ramana; Mahadevan, S V
2016-01-01
Objectives Characterise the demographics, management and outcomes of obstetric patients transported by emergency medical services (EMS). Design Prospective observational study. Setting Five Indian states using a centralised EMS agency that transported 3.1 million pregnant women in 2014. Participants This study enrolled a convenience sample of 1684 women in third trimester of pregnancy calling with a ‘pregnancy-related’ problem for free-of-charge ambulance transport. Calls were deemed ‘pregnancy related’ if categorised by EMS dispatchers as ‘pregnancy’, ‘childbirth’, ‘miscarriage’ or ‘labour pains’. Interfacility transfers, patients absent on ambulance arrival and patients refusing care were excluded. Main outcome measures Emergency medical technician (EMT) interventions, method of delivery and death. Results The median age enrolled was 23 years (IQR 21–25). Women were primarily from rural or tribal areas (1550/1684 (92.0%)) and lower economic strata (1177/1684 (69.9%)). Time from initial call to hospital arrival was longer for rural/tribal compared with urban patients (66 min (IQR 51–84) vs 56 min (IQR 42–73), respectively, p<0.0001). EMTs assisted delivery in 44 women, delivering the placenta in 33/44 (75%), performing transabdominal uterine massage in 29/33 (87.9%) and administering oxytocin in none (0%). There were 1411 recorded deliveries. Most women delivered at a hospital (1212/1411 (85.9%)), however 126/1411 (8.9%) delivered at home following hospital discharge. Follow-up rates at 48 hours, 7 days and 42 days were 95.0%, 94.4% and 94.1%, respectively. Four women died, all within 48 hours. The caesarean section rate was 8.2% (116/1411). On multivariate regression analysis, women transported to private hospitals versus government primary health centres were less likely to deliver by caesarean section (OR 0.14 (0.05–0.43)) Conclusions Pregnant women from vulnerable Indian populations use free-of-charge EMS for
Analytical Chemistry Laboratory progress report for FY 1991
Green, D.W.; Heinrich, R.R.; Graczyk, D.G.; Lindahl, P.C.; Boparai, A.S.
1991-12-01
The purpose of this report is to summarize the activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for Fiscal Year 1991 (October 1990 through September 1991). This is the eighth annual report for the ACL. The Analytical Chemistry Laboratory is a full-cost-recovery service center, with the primary mission of providing a broad range of analytical chemistry support services to the scientific and engineering programs at ANL. In addition, the ACL conducts a research program in analytical chemistry, works on instrumental and methods development, and provides analytical services for governmental, educational, and industrial organizations. The ACL handles a wide range of analytical problems, from routine standard analyses to unique problems that require significant development of methods and techniques.
Analytical Chemistry Laboratory: Progress report for FY 1988
Green, D.W.; Heinrich, R.R.; Graczyk, D.G.; Lindahl, P.C.; Erickson, M.D.
1988-12-01
The purpose of this report is to summarize the activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for fiscal year 1988 (October 1987 through September 1988). The Analytical Chemistry Laboratory is a full-cost recovery service center, with the primary mission of providing a broad range of analytical chemistry support services to the scientific and engineering programs at ANL. In addition, the ACL conducts a research program in analytical chemistry, works on instrumental and methods development, and provides analytical services for governmental, educational, and industrial organizations. The ACL handles a wide range of analytical problems, from routine standard analyses to unique problems that require significant development of methods and techniques.
Sherlock Holmes, Master Problem Solver.
ERIC Educational Resources Information Center
Ballew, Hunter
1994-01-01
Shows the connections between Sherlock Holmes's investigative methods and mathematical problem solving, including observations, characteristics of the problem solver, importance of data, questioning the obvious, learning from experience, learning from errors, and indirect proof. (MKR)
Identification of structural interface characteristics using component mode synthesis
NASA Technical Reports Server (NTRS)
Huckelbridge, A. A.; Lawrence, C.
1987-01-01
The inability to adequately model connections has limited the ability to predict overall system dynamic response. Connections between structural components are often mechanically complex and difficult to accurately model analytically. Improved analytical models for connections are needed to improve system dynamic predictions. This study explores combining Component Mode synthesis methods for coupling structural components with Parameter Identification procedures for improving the analytical modeling of the connections. Improvements in the connection properties are computed in terms of physical parameters so the physical characteristics of the connections can be better understood, in addition to providing improved input for the system model. Two sample problems, one utilizing simulated data, the other using experimental data from a rotor dynamic test rig are presented.
Identification of structural interface characteristics using component mode synthesis
NASA Technical Reports Server (NTRS)
Huckelbridge, A. A.; Lawrence, C.
1987-01-01
The inability to adequately model connections has limited the ability to predict overall system dynamic response. Connections between structural components are often mechanically complex and difficult to accurately model analytically. Improved analytical models for connections are needed to improve system dynamic predictions. This study explores combining Component Mode synthesis methods for coupling structural components with Parameter Identification procedures for improving the analytical modeling of the connections. Improvements in the connection properties are computed in terms of physical parameters so the physical characteristics of the connections can be better understood, in addition to providing improved input for the system model. Two sample problems, one utilizing simulated data, the other using experimental data from a rotor dynamic test rig, are presented.
Identification of structural interface characteristics using component mode synthesis
NASA Technical Reports Server (NTRS)
Huckelbridge, A. A.; Lawrence, C.
1989-01-01
The inability to adequately model connections has limited the ability to predict overall system dynamic response. Connections between structural components are often mechanically complex and difficult to accurately model analytically. Improved analytical models for connections are needed to improve system dynamic predictions. This study explores combining Component Mode synthesis methods for coupling structural components with Parameter Identification procedures for improving the analytical modeling of the connections. Improvements in the connection properties are computed in terms of physical parameters so the physical characteristics of the connections can be better understood, in addition to providing improved input for the system model. Two sample problems, one utilizing simulated data, the other using experimental data from a rotor dynamic test rig, are presented.
Frontiers in analytical chemistry
Amato, I.
1988-12-15
Doing more with less was the modus operandi of R. Buckminster Fuller, the late science genius, and inventor of such things as the geodesic dome. In late September, chemists described their own version of this maxim--learning more chemistry from less material and in less time--in a symposium titled Frontiers in Analytical Chemistry at the 196th National Meeting of the American Chemical Society in Los Angeles. Symposium organizer Allen J. Bard of the University of Texas at Austin assembled six speakers, himself among them, to survey pretty widely different areas of analytical chemistry.
Integrated Array/Metadata Analytics
NASA Astrophysics Data System (ADS)
Misev, Dimitar; Baumann, Peter
2015-04-01
Data comes in various forms and types, and integration usually presents a problem that is often simply ignored and solved with ad-hoc solutions. Multidimensional arrays are an ubiquitous data type, that we find at the core of virtually all science and engineering domains, as sensor, model, image, statistics data. Naturally, arrays are richly described by and intertwined with additional metadata (alphanumeric relational data, XML, JSON, etc). Database systems, however, a fundamental building block of what we call "Big Data", lack adequate support for modelling and expressing these array data/metadata relationships. Array analytics is hence quite primitive or non-existent at all in modern relational DBMS. Recognizing this, we extended SQL with a new SQL/MDA part seamlessly integrating multidimensional array analytics into the standard database query language. We demonstrate the benefits of SQL/MDA with real-world examples executed in ASQLDB, an open-source mediator system based on HSQLDB and rasdaman, that already implements SQL/MDA.
[Contributions and novelties from Functional Analytic Psychotherapy].
Ferro García, Rafael; Valero Aguayo, Luis; López Bermúdez, Miguel A
2007-08-01
Functional Analytic Psychotherapy is based on the principles of radical behaviourism. It emphasises the impact of events occurring during therapeutic sessions, the therapist-client interaction context, functional equivalence of environments, natural reinforcement, and shaping by the therapist. Functional Analytic Psychotherapy makes use of both the basic principles of behaviour analysis: individual functional assessment and application of in vivo treatment. This paper analyses novelties and new contributions of this therapy. New contributions are classified in various categories: integration with other psychotherapies, improvement of therapeutic skills, methods for evaluation and data recording in therapy, its application to several clinical problems, and studies of its efficacy. PMID:17617985
Analytical Services Management System
Church, Shane; Nigbor, Mike; Hillman, Daniel
2005-03-30
Analytical Services Management System (ASMS) provides sample management services. Sample management includes sample planning for analytical requests, sample tracking for shipping and receiving by the laboratory, receipt of the analytical data deliverable, processing the deliverable and payment of the laboratory conducting the analyses. ASMS is a web based application that provides the ability to manage these activities at multiple locations for different customers. ASMS provides for the assignment of single to multiple samples for standard chemical and radiochemical analyses. ASMS is a flexible system which allows the users to request analyses by line item code. Line item codes are selected based on the Basic Ordering Agreement (BOA) format for contracting with participating laboratories. ASMS also allows contracting with non-BOA laboratories using a similar line item code contracting format for their services. ASMS allows sample and analysis tracking from sample planning and collection in the field through sample shipment, laboratory sample receipt, laboratory analysis and submittal of the requested analyses, electronic data transfer, and payment of the laboratories for the completed analyses. The software when in operation contains business sensitive material that is used as a principal portion of the Kaiser Analytical Management Services business model. The software version provided is the most recent version, however the copy of the application does not contain business sensitive data from the associated Oracle tables such as contract information or price per line item code.
Analytical Chemistry Laboratory
NASA Technical Reports Server (NTRS)
Anderson, Mark
2013-01-01
The Analytical Chemistry and Material Development Group maintains a capability in chemical analysis, materials R&D failure analysis and contamination control. The uniquely qualified staff and facility support the needs of flight projects, science instrument development and various technical tasks, as well as Cal Tech.
Analytical Services Management System
Energy Science and Technology Software Center (ESTSC)
2005-03-30
Analytical Services Management System (ASMS) provides sample management services. Sample management includes sample planning for analytical requests, sample tracking for shipping and receiving by the laboratory, receipt of the analytical data deliverable, processing the deliverable and payment of the laboratory conducting the analyses. ASMS is a web based application that provides the ability to manage these activities at multiple locations for different customers. ASMS provides for the assignment of single to multiple samples for standardmore » chemical and radiochemical analyses. ASMS is a flexible system which allows the users to request analyses by line item code. Line item codes are selected based on the Basic Ordering Agreement (BOA) format for contracting with participating laboratories. ASMS also allows contracting with non-BOA laboratories using a similar line item code contracting format for their services. ASMS allows sample and analysis tracking from sample planning and collection in the field through sample shipment, laboratory sample receipt, laboratory analysis and submittal of the requested analyses, electronic data transfer, and payment of the laboratories for the completed analyses. The software when in operation contains business sensitive material that is used as a principal portion of the Kaiser Analytical Management Services business model. The software version provided is the most recent version, however the copy of the application does not contain business sensitive data from the associated Oracle tables such as contract information or price per line item code.« less
Analytics: Changing the Conversation
ERIC Educational Resources Information Center
Oblinger, Diana G.
2013-01-01
In this third and concluding discussion on analytics, the author notes that we live in an information culture. We are accustomed to having information instantly available and accessible, along with feedback and recommendations. We want to know what people think and like (or dislike). We want to know how we compare with "others like me."…
ERIC Educational Resources Information Center
Buckingham Shum, Simon; Ferguson, Rebecca
2012-01-01
We propose that the design and implementation of effective "Social Learning Analytics (SLA)" present significant challenges and opportunities for both research and enterprise, in three important respects. The first is that the learning landscape is extraordinarily turbulent at present, in no small part due to technological drivers. Online social…
ERIC Educational Resources Information Center
Freeman, Elisabeth
1996-01-01
Presents a brief history of Ada Byron King, Countess of Lovelace, focusing on her primary role in the development of the Analytical Engine--the world's first computer. Describes the Ada Project (TAP), a centralized World Wide Web site that serves as a clearinghouse for information related to women in computing, and provides a Web address for…
Analytical Instrument Obsolescence Examined.
ERIC Educational Resources Information Center
Haggin, Joseph
1982-01-01
The threat of instrument obsolescence and tight federal budgets have conspired to threaten the existence of research analytical laboratories. Despite these and other handicaps most existing laboratories expect to keep operating in support of basic research, though there may be serious penalties in the future unless funds are forthcoming. (Author)
Analytical prediction of reverse buckling pressure for thin shells
NASA Technical Reports Server (NTRS)
Martindale, D. L.; Urbanac, C.
1970-01-01
Analytical technique is developed for prediction of reverse buckling in thin curved shells. Test data indicate technique predicts actual reverse buckling pressure within 10 percent, and should be useful for analytical prediction of reversed condition failure for problems such as explosive decomposition through vacuum failure.
Analytic solutions of a general nonlinear functional equations near resonance
NASA Astrophysics Data System (ADS)
Xu, Bing; Zhang, Weinian
2006-05-01
Existence of analytic solutions of a general class of nonlinear functional equations is discussed. This general class includes some specific functional equations studied recently. Moreover, we can generalize this problem to finding analytic solutions of a general class of iterative equations.
Analytic Cognitive Style Predicts Religious and Paranormal Belief
ERIC Educational Resources Information Center
Pennycook, Gordon; Cheyne, James Allan; Seli, Paul; Koehler, Derek J.; Fugelsang, Jonathan A.
2012-01-01
An analytic cognitive style denotes a propensity to set aside highly salient intuitions when engaging in problem solving. We assess the hypothesis that an analytic cognitive style is associated with a history of questioning, altering, and rejecting (i.e., unbelieving) supernatural claims, both religious and paranormal. In two studies, we examined…
Semi-Analytical Approches to Variable Density Flows.
NASA Astrophysics Data System (ADS)
Telyakovskiy, A. S.; Wheatcraft, S. W.
2005-12-01
A few classical problems are known in the theory of variable density flows: Henry's, Elder's and Yusa's problems. A very limited number of analytical solutions are known for these problems. The goal of this work is to obtain new analytical/semi-analytical solutions that would provide insights into the nature of these problems. Also, it would allow more efficient testing of numerical codes that can be used for many applications. Today these codes are tested only against an extremely limited number of known solutions. So such solutions will be extremely useful to the groundwater hydrology community. Sea water ntrusion, the most important of variable density flow problems, is a very big problem in the world today, with a significant portion of the world's population living within 50 km of the world's oceans.
... labor starts before 37 completed weeks of pregnancy Problems with the umbilical cord Problems with the position of the baby, such as ... feet first Birth injuries For some of these problems, the baby may need to be delivered surgically ...
... version of this page please turn Javascript on. Balance Problems About Balance Problems Have you ever felt dizzy, lightheaded, or ... dizziness problem during the past year. Why Good Balance is Important Having good balance means being able ...
Rotordynamic Instability Problems in High-Performance Turbomachinery, 1986
NASA Technical Reports Server (NTRS)
1987-01-01
The first rotordynamics workshop proceedings (NASA CP-2133, 1980) emphasized a feeling of uncertainty in predicting the stability of characteristics of high-performance turbomachinery. In the second workshop proceedings (NASA CP-2250, 1982) these uncertainities were reduced through programs established to systematically resolve problems, with emphasis on experimental validiation of the forces that influence rotordynamics. In third proceedings (NASA CP-2338, 1984) many programs for predicting or measuring forces and force coefficients in high-performance turbomachinery produced results. Data became available for designing new machines with enhanced stability characteristics or for upgrading existing machines. The present workshop proceedings illustrates a continued trend toward a more unified view of rotordynamic instability problems and several encouraging new analytical developments.
MCNP: Photon benchmark problems
Whalen, D.J.; Hollowell, D.E.; Hendricks, J.S.
1991-09-01
The recent widespread, markedly increased use of radiation transport codes has produced greater user and institutional demand for assurance that such codes give correct results. Responding to these pressing requirements for code validation, the general purpose Monte Carlo transport code MCNP has been tested on six different photon problem families. MCNP was used to simulate these six sets numerically. Results for each were compared to the set's analytical or experimental data. MCNP successfully predicted the analytical or experimental results of all six families within the statistical uncertainty inherent in the Monte Carlo method. From this we conclude that MCNP can accurately model a broad spectrum of photon transport problems. 8 refs., 30 figs., 5 tabs.
Dielectric barrier discharges in analytical chemistry.
Meyer, C; Müller, S; Gurevich, E L; Franzke, J
2011-06-21
The present review reflects the importance of dielectric barrier discharges in analytical chemistry. Special about this discharge is-and in contrast to usual discharges with direct current-that the plasma is separated from one or two electrodes by a dielectric barrier. This gives rise to two main features of the dielectric barrier discharges; it can serve as dissociation and excitation device and as ionization mechanism, respectively. The article portrays the various application fields for dielectric barrier discharges in analytical chemistry, for example the use for elemental detection with optical spectrometry or as ionization source for mass spectrometry. Besides the introduction of different kinds of dielectric barrier discharges used for analytical chemistry from the literature, a clear and concise classification of dielectric barrier discharges into capacitively coupled discharges is provided followed by an overview about the characteristics of a dielectric barrier discharge concerning discharge properties and the ignition mechanism. PMID:21562672
NASA Technical Reports Server (NTRS)
Schmidt, R. F.
1987-01-01
This document discusses the determination of caustic surfaces in terms of rays, reflectors, and wavefronts. Analytical caustics are obtained as a family of lines, a set of points, and several types of equations for geometries encountered in optics and microwave applications. Standard methods of differential geometry are applied under different approaches: directly to reflector surfaces, and alternatively, to wavefronts, to obtain analytical caustics of two sheets or branches. Gauss/Seidel aberrations are introduced into the wavefront approach, forcing the retention of all three coefficients of both the first- and the second-fundamental forms of differential geometry. An existing method for obtaining caustic surfaces through exploitation of the singularities in flux density is examined, and several constant-intensity contour maps are developed using only the intrinsic Gaussian, mean, and normal curvatures of the reflector. Numerous references are provided for extending the material of the present document to the morphologies of caustics and their associated diffraction patterns.
Requirements for Predictive Analytics
Troy Hiltbrand
2012-03-01
It is important to have a clear understanding of how traditional Business Intelligence (BI) and analytics are different and how they fit together in optimizing organizational decision making. With tradition BI, activities are focused primarily on providing context to enhance a known set of information through aggregation, data cleansing and delivery mechanisms. As these organizations mature their BI ecosystems, they achieve a clearer picture of the key performance indicators signaling the relative health of their operations. Organizations that embark on activities surrounding predictive analytics and data mining go beyond simply presenting the data in a manner that will allow decisions makers to have a complete context around the information. These organizations generate models based on known information and then apply other organizational data against these models to reveal unknown information.
Brune, D.; Forkman, B.; Persson, B.
1984-01-01
This book covers the general theories and techniques of nuclear chemical analysis, directed at applications in analytical chemistry, nuclear medicine, radiophysics, agriculture, environmental sciences, geological exploration, industrial process control, etc. The main principles of nuclear physics and nuclear detection on which the analysis is based are briefly outlined. An attempt is made to emphasise the fundamentals of activation analysis, detection and activation methods, as well as their applications. The book provides guidance in analytical chemistry, agriculture, environmental and biomedical sciences, etc. The contents include: the nuclear periodic system; nuclear decay; nuclear reactions; nuclear radiation sources; interaction of radiation with matter; principles of radiation detectors; nuclear electronics; statistical methods and spectral analysis; methods of radiation detection; neutron activation analysis; charged particle activation analysis; photon activation analysis; sample preparation and chemical separation; nuclear chemical analysis in biological and medical research; the use of nuclear chemical analysis in the field of criminology; nuclear chemical analysis in environmental sciences, geology and mineral exploration; and radiation protection.
Analytic holographic superconductor
NASA Astrophysics Data System (ADS)
Herzog, Christopher P.
2010-06-01
We investigate a holographic superconductor that admits an analytic treatment near the phase transition. In the dual 3+1-dimensional field theory, the phase transition occurs when a scalar operator of scaling dimension two gets a vacuum expectation value. We calculate current-current correlation functions along with the speed of second sound near the critical temperature. We also make some remarks about critical exponents. An analytic treatment is possible because an underlying Heun equation describing the zero mode of the phase transition has a polynomial solution. Amusingly, the treatment here may generalize for an order parameter with any integer spin, and we propose a Lagrangian for a spin-two holographic superconductor.
Cowell, Andrew J.; Cowell, Amanda K.
2009-08-29
This paper discusses the design and use of anthropomorphic computer characters as nonplayer characters (NPC’s) within analytical games. These new environments allow avatars to play a central role in supporting training and education goals instead of planning the supporting cast role. This new ‘science’ of gaming, driven by high-powered but inexpensive computers, dedicated graphics processors and realistic game engines, enables game developers to create learning and training opportunities on par with expensive real-world training scenarios. However, there needs to be care and attention placed on how avatars are represented and thus perceived. A taxonomy of non-verbal behavior is presented and its application to analytical gaming discussed.
The Guderley problem revisited
NASA Astrophysics Data System (ADS)
Ramsey, Scott D.; Kamm, James R.; Bolstad, John H.
2012-02-01
The self-similar converging-diverging shock wave problem introduced by Guderley in 1942 has been the source of considerable mathematical and physical interest. We investigate a novel application of the Guderley solution as a unique and challenging code verification test problem for compressible flow algorithms; this effort requires a unified understanding of the problem's mathematical and computational subtleties. Hence, we review the simplifications and group invariance properties that reduce the compressible flow equations for a polytropic gas to two coupled nonlinear eigenvalue problems: the first for the similarity exponent in the converging regime, and the second for a trajectory multiplier in the diverging regime. The information we provide, together with previously published material, gives a complete description of the computational steps required to construct a semi-analytic Guderley solution. We employ the problem in a quantitative code verification analysis of a cell-centred, finite volume, Eulerian compressible flow algorithm. Lastly, in appended material, we introduce a new approximation for the similarity exponent, which may prove useful in the future construction of certain semi-analytic Guderley solutions.
Industrial Analytics Corporation
Industrial Analytics Corporation
2004-01-30
The lost foam casting process is sensitive to the properties of the EPS patterns used for the casting operation. In this project Industrial Analytics Corporation (IAC) has developed a new low voltage x-ray instrument for x-ray radiography of very low mass EPS patterns. IAC has also developed a transmitted visible light method for characterizing the properties of EPS patterns. The systems developed are also applicable to other low density materials including graphite foams.
Competing on talent analytics.
Davenport, Thomas H; Harris, Jeanne; Shapiro, Jeremy
2010-10-01
Do investments in your employees actually affect workforce performance? Who are your top performers? How can you empower and motivate other employees to excel? Leading-edge companies such as Google, Best Buy, Procter & Gamble, and Sysco use sophisticated data-collection technology and analysis to answer these questions, leveraging a range of analytics to improve the way they attract and retain talent, connect their employee data to business performance, differentiate themselves from competitors, and more. The authors present the six key ways in which companies track, analyze, and use data about their people-ranging from a simple baseline of metrics to monitor the organization's overall health to custom modeling for predicting future head count depending on various "what if" scenarios. They go on to show that companies competing on talent analytics manage data and technology at an enterprise level, support what analytical leaders do, choose realistic targets for analysis, and hire analysts with strong interpersonal skills as well as broad expertise. PMID:20929194
Analytical design of intelligent machines
NASA Technical Reports Server (NTRS)
Saridis, George N.; Valavanis, Kimon P.
1987-01-01
The problem of designing 'intelligent machines' to operate in uncertain environments with minimum supervision or interaction with a human operator is examined. The structure of an 'intelligent machine' is defined to be the structure of a Hierarchically Intelligent Control System, composed of three levels hierarchically ordered according to the principle of 'increasing precision with decreasing intelligence', namely: the organizational level, performing general information processing tasks in association with a long-term memory; the coordination level, dealing with specific information processing tasks with a short-term memory; and the control level, which performs the execution of various tasks through hardware using feedback control methods. The behavior of such a machine may be managed by controls with special considerations and its 'intelligence' is directly related to the derivation of a compatible measure that associates the intelligence of the higher levels with the concept of entropy, which is a sufficient analytic measure that unifies the treatment of all the levels of an 'intelligent machine' as the mathematical problem of finding the right sequence of internal decisions and controls for a system structured in the order of intelligence and inverse order of precision such that it minimizes its total entropy. A case study on the automatic maintenance of a nuclear plant illustrates the proposed approach.
The chemistry of chromium and some resulting analytical problems.
Shupack, S I
1991-01-01
Chromium, named for its many-colored compounds, exists in the oxidation states of -2 to +6 inclusively. The compounds exhibit a wide range of geometries including square planar, tetrahedral, octahedral, and various distorted geometries. Chromium is found in nature principally as the chromite ore FeCr2O4 in which chromium is in the +3 state. The existence of a particular oxidation state is dependent on many factors including pH, redox potentials, and kinetics. Thermodynamically, +3 and +2 are the most stable states, while the +3 and +6 oxidation states are the most common ones found in aqueous solution. Kinetically, chromium +3 is substitutionally inert: for water exchange k(sec-1) = 2.5 x 10(-6), due to the presence of the half-filled d(t2g)3.4A2g state. On the other hand, protonation/deprotonation is quite rapid. Polymerization is very slow but is promoted at higher pHs; acid cleavage of the protonated oligomers is also quite slow. Chromium +6 as the chromate ion is strongly oxidizing at low pHs and less so in basic solution. The chromate ion does form some polyacids and polyanions. These factors must be considered in analyzing samples for total chromium and for the amounts of each oxidation state. Images FIGURE 1. PMID:1935853
Analytical Chemistry Laboratory progress report for FY 1985
Green, D.W.; Heinrich, R.R.; Jensen, K.J.
1985-12-01
The Analytical Chemistry Laboratory is a full-cost-recovery service center, with the primary mission of providing a broad range of technical support services to the scientific and engineering programs at ANL. In addition, ACL conducts a research program in analytical chemistry, works on instrumental and methods development, and provides analytical services for governmental, educational, and industrial organizations. The ACL handles a wide range of analytical problems, from routine standard analyses to unique problems that require significant development of methods and techniques. The purpose of this report is to summarize the technical and administrative activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for Fiscal Year 1985 (October 1984 through September 1985). This is the second annual report for the ACL. 4 figs., 1 tab.
Kinetic corrections from analytic non-Maxwellian distribution functions in magnetized plasmas
Izacard, Olivier
2016-08-02
In magnetized plasma physics, almost all developed analytic theories assume a Maxwellian distribution function (MDF) and in some cases small deviations are described using the perturbation theory. The deviations with respect to the Maxwellian equilibrium, called kinetic effects, are required to be taken into account especially for fusion reactor plasmas. Generally, because the perturbation theory is not consistent with observed steady-state non-Maxwellians, these kinetic effects are numerically evaluated by very central processing unit (CPU)-expensive codes, avoiding the analytic complexity of velocity phase space integrals. We develop here a new method based on analytic non-Maxwellian distribution functions constructed from non-orthogonal basismore » sets in order to (i) use as few parameters as possible, (ii) increase the efficiency to model numerical and experimental non-Maxwellians, (iii) help to understand unsolved problems such as diagnostics discrepancies from the physical interpretation of the parameters, and (iv) obtain analytic corrections due to kinetic effects given by a small number of terms and removing the numerical error of the evaluation of velocity phase space integrals. This work does not attempt to derive new physical effects even if it could be possible to discover one from the better understandings of some unsolved problems, but here we focus on the analytic prediction of kinetic corrections from analytic non-Maxwellians. As applications, examples of analytic kinetic corrections are shown for the secondary electron emission, the Langmuir probe characteristic curve, and the entropy. This is done by using three analytic representations of the distribution function: the Kappa distribution function, the bi-modal or a new interpreted non-Maxwellian distribution function (INMDF). The existence of INMDFs is proved by new understandings of the experimental discrepancy of the measured electron temperature between two diagnostics in JET. As main
Kinetic corrections from analytic non-Maxwellian distribution functions in magnetized plasmas
NASA Astrophysics Data System (ADS)
Izacard, Olivier
2016-08-01
In magnetized plasma physics, almost all developed analytic theories assume a Maxwellian distribution function (MDF) and in some cases small deviations are described using the perturbation theory. The deviations with respect to the Maxwellian equilibrium, called kinetic effects, are required to be taken into account especially for fusion reactor plasmas. Generally, because the perturbation theory is not consistent with observed steady-state non-Maxwellians, these kinetic effects are numerically evaluated by very central processing unit (CPU)-expensive codes, avoiding the analytic complexity of velocity phase space integrals. We develop here a new method based on analytic non-Maxwellian distribution functions constructed from non-orthogonal basis sets in order to (i) use as few parameters as possible, (ii) increase the efficiency to model numerical and experimental non-Maxwellians, (iii) help to understand unsolved problems such as diagnostics discrepancies from the physical interpretation of the parameters, and (iv) obtain analytic corrections due to kinetic effects given by a small number of terms and removing the numerical error of the evaluation of velocity phase space integrals. This work does not attempt to derive new physical effects even if it could be possible to discover one from the better understandings of some unsolved problems, but here we focus on the analytic prediction of kinetic corrections from analytic non-Maxwellians. As applications, examples of analytic kinetic corrections are shown for the secondary electron emission, the Langmuir probe characteristic curve, and the entropy. This is done by using three analytic representations of the distribution function: the Kappa distribution function, the bi-modal or a new interpreted non-Maxwellian distribution function (INMDF). The existence of INMDFs is proved by new understandings of the experimental discrepancy of the measured electron temperature between two diagnostics in JET. As main results, it
Glossary of Analytical Chemistry Terms (GAT)
NASA Astrophysics Data System (ADS)
Wenclawiak, Bernd
Why is it so important to have a glossary of analytical terms? Because there are so many different acronyms, abbreviations, and incorrectly used ‘terms', that even specialists sometimes have problems in understanding each other. A glossary is like a dictionary with the terms being the words in the vocabulary. Unfortunately not all words are found in one source. This chapter is a compilation of the most used terms.
Analytical study of shimmy of airplane wheels
NASA Technical Reports Server (NTRS)
Bourcier De Carbon, Christian
1952-01-01
The problem of shimmy of a castering wheel, such as the nose wheel of a tricycle gear airplane, is treated analytically. The flexibility of the tire is considered to be the primary cause of shimmy. The rather simple theory developed agrees rather well with previous experimental results. The author suggests that shimmy may be eliminated through a suitable choice of landing gear dimensions in lieu of a damper.
Supersymmetry identifies molecular Stark states whose eigenproperties can be obtained analytically
NASA Astrophysics Data System (ADS)
Lemeshko, Mikhail; Mustafa, Mustafa; Kais, Sabre; Friedrich, Bretislav
2011-06-01
We made use of supersymmetric (SUSY) quantum mechanics to find the condition under which the Stark effect problem for a polar and polarizable closed-shell diatomic molecule subjected to collinear electrostatic and nonresonant radiative fields becomes exactly solvable. The condition \\Delta \\omega = \\frac{\\omega^2}{4 (m+1)^2 } connects values of the dimensionless parameters ω and Δω that characterize the strengths of the permanent and induced dipole interactions of the molecule with the respective fields. The exact solutions are obtained for the \\vert \\skew5\\tilde{J}=m,m;\\omega,\\Delta \\omega\\rangle family of 'stretched' states. The field-free and strong-field limits of the combined-fields problem were found to exhibit supersymmetry and shape invariance, which is indeed the reason why they are analytically solvable. By making use of the analytic form of the \\vert \\skew5\\tilde{J}=m,m;\\omega,\\Delta \\omega\\rangle wavefunctions, we obtained simple formulae for the expectation values of the space-fixed electric dipole moment, the alignment cosine and the angular momentum squared, and derived a 'sum rule' that combines the above expectation values into a formula for the eigenenergy. The analytic expressions for the characteristics of the strongly oriented and aligned states provide direct access to the values of the interaction parameters required for creating such states in the laboratory.
NASA Astrophysics Data System (ADS)
Schnase, J. L.; Duffy, D. Q.; McInerney, M. A.; Tamkin, G. S.; Thompson, J. H.; Gill, R.; Grieg, C. M.
2012-12-01
MERRA Analytic Services (MERRA/AS) is a cyberinfrastructure resource for developing and evaluating a new generation of climate data analysis capabilities. MERRA/AS supports OBS4MIP activities by reducing the time spent in the preparation of Modern Era Retrospective-Analysis for Research and Applications (MERRA) data used in data-model intercomparison. It also provides a testbed for experimental development of high-performance analytics. MERRA/AS is a cloud-based service built around the Virtual Climate Data Server (vCDS) technology that is currently used by the NASA Center for Climate Simulation (NCCS) to deliver Intergovernmental Panel on Climate Change (IPCC) data to the Earth System Grid Federation (ESGF). Crucial to its effectiveness, MERRA/AS's servers will use a workflow-generated realizable object capability to perform analyses over the MERRA data using the MapReduce approach to parallel storage-based computation. The results produced by these operations will be stored by the vCDS, which will also be able to host code sets for those who wish to explore the use of MapReduce for more advanced analytics. While the work described here will focus on the MERRA collection, these technologies can be used to publish other reanalysis, observational, and ancillary OBS4MIP data to ESGF and, importantly, offer an architectural approach to climate data services that can be generalized to applications and customers beyond the traditional climate research community. In this presentation, we describe our approach, experiences, lessons learned,and plans for the future.; (A) MERRA/AS software stack. (B) Example MERRA/AS interfaces.
Mixed formulation for frictionless contact problems
NASA Technical Reports Server (NTRS)
Noor, Ahmed K.; Kim, Kyun O.
1989-01-01
Simple mixed finite element models and a computational precedure are presented for the solution of frictionless contact problems. The analytical formulation is based on a form of Reissner's large rotation theory of the structure with the effects of transverse shear deformation included. The contact conditions are incorporated into the formulation by using a perturbed Lagrangian approach with the fundamental unknowns consisting of the internal forces (stress resultants), the generalized displacements, and the Lagrange multipliers associated with the contact conditions. The element characteristic array are obtained by using a modified form of the two-field Hellinger-Reissner mixed variational principle. The internal forces and the Lagrange multipliers are allowed to be discontinuous at interelement boundaries. The Newton-Raphson iterative scheme is used for the solution of the nonlinear algebraic equations, and the determination of the contact area and the contact pressures.
Automation of analytical isotachophoresis
NASA Technical Reports Server (NTRS)
Thormann, Wolfgang
1985-01-01
The basic features of automation of analytical isotachophoresis (ITP) are reviewed. Experimental setups consisting of narrow bore tubes which are self-stabilized against thermal convection are considered. Sample detection in free solution is discussed, listing the detector systems presently used or expected to be of potential use in the near future. The combination of a universal detector measuring the evolution of ITP zone structures with detector systems specific to desired components is proposed as a concept of an automated chemical analyzer based on ITP. Possible miniaturization of such an instrument by means of microlithographic techniques is discussed.
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... ankles and toes. Other types of arthritis include gout or pseudogout. Sometimes, there is a mechanical problem ... for more information on osteoarthritis, rheumatoid arthritis and gout. How Common are Joint Problems? Osteoarthritis, which affects ...
Analytical Approximation of Spectrum for Pulse X-ray Tubes
NASA Astrophysics Data System (ADS)
Vavilov, S.; Koshkin, G.; Udod, V.; Fofanof, O.
2016-01-01
Among the main characteristics of the pulsed X-ray apparatuses the spectral energy characteristics are the most important ones: the spectral distribution of the photon energy, effective and maximum energy of quanta. Knowing the spectral characteristics of the radiation of pulse sources is very important for the practical use of them in non-destructive testing. We have attempted on the analytical approximation of the pulsed X-ray apparatuses spectra obtained in the different experimental papers. The results of the analytical approximation of energy spectrum for pulse X-ray tube are presented. Obtained formulas are adequate to experimental data and can be used by designing pulsed X-ray apparatuses.
Supporting Problem Solving in PBL
ERIC Educational Resources Information Center
Jonassen, David
2011-01-01
Although the characteristics of PBL (problem focused, student centered, self-directed, etc.) are well known, the components of a problem-based learning environment (PBLE) and the cognitive scaffolds necessary to support learning to solve different kinds of problems with different learners is less clear. This paper identifies the different…
Quality Indicators for Learning Analytics
ERIC Educational Resources Information Center
Scheffel, Maren; Drachsler, Hendrik; Stoyanov, Slavi; Specht, Marcus
2014-01-01
This article proposes a framework of quality indicators for learning analytics that aims to standardise the evaluation of learning analytics tools and to provide a mean to capture evidence for the impact of learning analytics on educational practices in a standardised manner. The criteria of the framework and its quality indicators are based on…
Learning Analytics: Readiness and Rewards
ERIC Educational Resources Information Center
Friesen, Norm
2013-01-01
This position paper introduces the relatively new field of learning analytics, first by considering the relevant meanings of both "learning" and "analytics," and then by looking at two main levels at which learning analytics can be or has been implemented in educational organizations. Although integrated turnkey systems or…
The analytic renormalization group
NASA Astrophysics Data System (ADS)
Ferrari, Frank
2016-08-01
Finite temperature Euclidean two-point functions in quantum mechanics or quantum field theory are characterized by a discrete set of Fourier coefficients Gk, k ∈ Z, associated with the Matsubara frequencies νk = 2 πk / β. We show that analyticity implies that the coefficients Gk must satisfy an infinite number of model-independent linear equations that we write down explicitly. In particular, we construct "Analytic Renormalization Group" linear maps Aμ which, for any choice of cut-off μ, allow to express the low energy Fourier coefficients for |νk | < μ (with the possible exception of the zero mode G0), together with the real-time correlators and spectral functions, in terms of the high energy Fourier coefficients for |νk | ≥ μ. Operating a simple numerical algorithm, we show that the exact universal linear constraints on Gk can be used to systematically improve any random approximate data set obtained, for example, from Monte-Carlo simulations. Our results are illustrated on several explicit examples.
The Holstein polaron problem revisited
NASA Astrophysics Data System (ADS)
Tayebi, Amin; Zelevinsky, Vladimir
2016-06-01
The Holstein Hamiltonian was proposed half a century ago; since then, decades of research have come up empty handed in the pursuit of a closed-form solution. An exact solution to the two-site Holstein model is presented in this paper. The obtained results provide a clear image of the Hamiltonian structure and allow for the investigation of the symmetry, energy level crossings and polaronic characteristics of the system. The main mathematical tool is a three-term recurrence relation between the wave function amplitudes, which was obtained using the properties of a family of orthogonal functions, namely the Poisson–Charlier polynomials. It is shown that, with the appropriate choice of basis, the eigenfunctions of the problem naturally fall into two families (parities) associated with the discrete {{{Z}}}2 symmetry of the Hamiltonian. The asymptotic solution to the recurrence relation is found by using the Birkhoff expansion. The asymptotic sets the truncation criterion for the wave function, which ensures the accurate calculation of the energy levels for any strength of electron–phonon interaction. The level crossing of states with different parities is discussed and the exact points of broken symmetry are found analytically. The results are used as the building blocks for studying a four-site system. The inherited symmetries lead to the formation of a sparse matrix that is convenient for numerical calculations.
Energy Science and Technology Software Center (ESTSC)
2008-01-15
The Verde Analytic Modules permit the user to ingest openly available data feeds about phenomenology (storm tracks, wind, precipitation, earthquake, wildfires, and similar natural and manmade power grid disruptions and forecast power outages, restoration times, customers outaged, and key facilities that will lose power. Damage areas are predicted using historic damage criteria of the affected area. The modules use a cellular automata approach to estimating the distribution circuits assigned to geo-located substations. Population estimates servedmore » within the service areas are located within 1 km grid cells and converted to customer counts by conversion through demographic estimation of households and commercial firms within the population cells. Restoration times are estimated by agent-based simulation of restoration crews working according to utility published prioritization calibrated by historic performance.« less
2008-01-15
The Verde Analytic Modules permit the user to ingest openly available data feeds about phenomenology (storm tracks, wind, precipitation, earthquake, wildfires, and similar natural and manmade power grid disruptions and forecast power outages, restoration times, customers outaged, and key facilities that will lose power. Damage areas are predicted using historic damage criteria of the affected area. The modules use a cellular automata approach to estimating the distribution circuits assigned to geo-located substations. Population estimates served within the service areas are located within 1 km grid cells and converted to customer counts by conversion through demographic estimation of households and commercial firms within the population cells. Restoration times are estimated by agent-based simulation of restoration crews working according to utility published prioritization calibrated by historic performance.
Analytical sensor redundancy assessment
NASA Technical Reports Server (NTRS)
Mulcare, D. B.; Downing, L. E.; Smith, M. K.
1988-01-01
The rationale and mechanization of sensor fault tolerance based on analytical redundancy principles are described. The concept involves the substitution of software procedures, such as an observer algorithm, to supplant additional hardware components. The observer synthesizes values of sensor states in lieu of their direct measurement. Such information can then be used, for example, to determine which of two disagreeing sensors is more correct, thus enhancing sensor fault survivability. Here a stability augmentation system is used as an example application, with required modifications being made to a quadruplex digital flight control system. The impact on software structure and the resultant revalidation effort are illustrated as well. Also, the use of an observer algorithm for wind gust filtering of the angle-of-attack sensor signal is presented.
Normality in Analytical Psychology
Myers, Steve
2013-01-01
Although C.G. Jung’s interest in normality wavered throughout his career, it was one of the areas he identified in later life as worthy of further research. He began his career using a definition of normality which would have been the target of Foucault’s criticism, had Foucault chosen to review Jung’s work. However, Jung then evolved his thinking to a standpoint that was more aligned to Foucault’s own. Thereafter, the post Jungian concept of normality has remained relatively undeveloped by comparison with psychoanalysis and mainstream psychology. Jung’s disjecta membra on the subject suggest that, in contemporary analytical psychology, too much focus is placed on the process of individuation to the neglect of applications that consider collective processes. Also, there is potential for useful research and development into the nature of conflict between individuals and societies, and how normal people typically develop in relation to the spectrum between individuation and collectivity. PMID:25379262
Analytical aspects of the CEEM soil project.
Muntau, H; Rehnert, A; Desaules, A; Wagner, G; Theocharopoulos, S; Quevauviller, P
2001-01-01
In the past, exercises aiming at an assessment of data uncertainty in environmental analysis were usually restricted to the analysis step, while sampling and pre-analytical sample treatment was largely ignored. Collaborative studies on the quantification of sampling errors require, besides a suitable and well characterized test site, the availability of a reference laboratory for the analysis of all of the samples taken in the context of the study by all participants and also test methods which do not contribute large and variable uncertainties due to long and complex analytical methodologies. Here we summarize the major analytical aspects of a European project on the identification and quantification of sampling influences on the determination of lead, cadmium, copper and zinc in soil. The participant group included the leading soil analysis laboratories in Europe; the test site at Dornach (CH) was well suited for the purpose and showed high metal gradients and differentiated land use. The analytical methods (wavelength-dispersive X-ray fluorescence spectrometry and solid-state Zeeman AAS) used in the study showed stable performance characteristics within the confidence interval of the certified reference materials used for the measurement quality control over the entire project period. Additionally, double-blind tests on split samples showed agreement of data in very narrow limits thus demonstrating the reliability of the reference database. PMID:11213186
Analytical-numerical solution of a nonlinear integrodifferential equation in econometrics
NASA Astrophysics Data System (ADS)
Kakhktsyan, V. M.; Khachatryan, A. Kh.
2013-07-01
A mixed problem for a nonlinear integrodifferential equation arising in econometrics is considered. An analytical-numerical method is proposed for solving the problem. Some numerical results are presented.
Analytic Theory and Control of the Motion of Spinning Rigid Bodies
NASA Technical Reports Server (NTRS)
Tsiotras, Panagiotis
1993-01-01
Numerical simulations are often resorted to, in order to understand the attitude response and control characteristics of a rigid body. However, this approach in performing sensitivity and/or error analyses may be prohibitively expensive and time consuming, especially when a large number of problem parameters are involved. Thus, there is an important role for analytical models in obtaining an understanding of the complex dynamical behavior. In this dissertation, new analytic solutions are derived for the complete attitude motion of spinning rigid bodies, under minimal assumptions. Hence, we obtain the most general solutions reported in the literature so far. Specifically, large external torques and large asymmetries are included in the problem statement. Moreover, problems involving large angular excursions are treated in detail. A new tractable formulation of the kinematics is introduced which proves to be extremely helpful in the search for analytic solutions of the attitude history of such kinds of problems. The main utility of the new formulation becomes apparent however, when searching for feedback control laws for stabilization and/or reorientation of spinning spacecraft. This is an inherently nonlinear problem, where standard linear control techniques fail. We derive a class of control laws for spin axis stabilization of symmetric spacecraft using only two pairs of gas jet actuators. Practically, this could correspond to a spacecraft operating in failure mode, for example. Theoretically, it is also an important control problem which, because of its difficulty, has received little, if any, attention in the literature. The proposed control laws are especially simple and elegant. A feedback control law that achieves arbitrary reorientation of the spacecraft is also derived, using ideas from invariant manifold theory. The significance of this research is twofold. First, it provides a deeper understanding of the fundamental behavior of rigid bodies subject to body
Noise characteristics of upper surface blown configurations: Analytical Studies
NASA Technical Reports Server (NTRS)
Reddy, N. N.; Tibbetts, J. G.; Pennock, A. P.; Tam, C. K. W.
1978-01-01
Noise and flow results of upper surface blown configurations were analyzed. The dominant noise source mechanisms were identified from experimental data. From far-field noise data for various geometric and operational parameters, an empirical noise prediction program was developed and evaluated by comparing predicted results with experimental data from other tests. USB aircraft compatibility studies were conducted using the described noise prediction and a cruise performance data base. A final design aircraft was selected and theory was developed for the noise from the trailing edge wake assuming it as a highly sheared layer.
[THE VERIFICATION OF ANALYTICAL CHARACTERISTICS OF THREE MODELS OF GLUCOMETERS].
Timofeev, A V; Khaibulina, E T; Mamonov, R A; Gorst, K A
2016-01-01
The individual portable systems of control of glucose level in blood commonly known as glucometers permit to patients with diabetes mellitus to independently correct pharmaceutical therapy. The effectiveness of this correction depends on accuracy of control of glucose level. The evaluation was implemented concerning minimal admissible accuracy and clinical accuracy of control of glucose level of devices Contour TC, Satellite Express and One Touch Select according standards expounded in GOST 15197-2011 and international standard ISO 15197-2013. It is demonstrated that Contour TC and One Touch Select meet the requirements of these standards in part of accuracy while Satellite Express does not. PMID:27183728
Analytic integrable systems: Analytic normalization and embedding flows
NASA Astrophysics Data System (ADS)
Zhang, Xiang
In this paper we mainly study the existence of analytic normalization and the normal form of finite dimensional complete analytic integrable dynamical systems. More details, we will prove that any complete analytic integrable diffeomorphism F(x)=Bx+f(x) in (Cn,0) with B having eigenvalues not modulus 1 and f(x)=O(|) is locally analytically conjugate to its normal form. Meanwhile, we also prove that any complete analytic integrable differential system x˙=Ax+f(x) in (Cn,0) with A having nonzero eigenvalues and f(x)=O(|) is locally analytically conjugate to its normal form. Furthermore we will prove that any complete analytic integrable diffeomorphism defined on an analytic manifold can be embedded in a complete analytic integrable flow. We note that parts of our results are the improvement of Moser's one in J. Moser, The analytic invariants of an area-preserving mapping near a hyperbolic fixed point, Comm. Pure Appl. Math. 9 (1956) 673-692 and of Poincaré's one in H. Poincaré, Sur l'intégration des équations différentielles du premier order et du premier degré, II, Rend. Circ. Mat. Palermo 11 (1897) 193-239. These results also improve the ones in Xiang Zhang, Analytic normalization of analytic integrable systems and the embedding flows, J. Differential Equations 244 (2008) 1080-1092 in the sense that the linear part of the systems can be nonhyperbolic, and the one in N.T. Zung, Convergence versus integrability in Poincaré-Dulac normal form, Math. Res. Lett. 9 (2002) 217-228 in the way that our paper presents the concrete expression of the normal form in a restricted case.
ENVIRONMENTAL ISOTOPES FOR RESOLUTION OF HYDROLOGY PROBLEMS
The use of environmental isotopes as tracers in the hydrosphere is increasing as analytical instrumentation improves and more applications are discovered. There exists still misconceptions on the role of isotopes in resolving hydrology problems. Naturally occurring isotopes in th...
Analytic cognitive style predicts religious and paranormal belief.
Pennycook, Gordon; Cheyne, James Allan; Seli, Paul; Koehler, Derek J; Fugelsang, Jonathan A
2012-06-01
An analytic cognitive style denotes a propensity to set aside highly salient intuitions when engaging in problem solving. We assess the hypothesis that an analytic cognitive style is associated with a history of questioning, altering, and rejecting (i.e., unbelieving) supernatural claims, both religious and paranormal. In two studies, we examined associations of God beliefs, religious engagement (attendance at religious services, praying, etc.), conventional religious beliefs (heaven, miracles, etc.) and paranormal beliefs (extrasensory perception, levitation, etc.) with performance measures of cognitive ability and analytic cognitive style. An analytic cognitive style negatively predicted both religious and paranormal beliefs when controlling for cognitive ability as well as religious engagement, sex, age, political ideology, and education. Participants more willing to engage in analytic reasoning were less likely to endorse supernatural beliefs. Further, an association between analytic cognitive style and religious engagement was mediated by religious beliefs, suggesting that an analytic cognitive style negatively affects religious engagement via lower acceptance of conventional religious beliefs. Results for types of God belief indicate that the association between an analytic cognitive style and God beliefs is more nuanced than mere acceptance and rejection, but also includes adopting less conventional God beliefs, such as Pantheism or Deism. Our data are consistent with the idea that two people who share the same cognitive ability, education, political ideology, sex, age and level of religious engagement can acquire very different sets of beliefs about the world if they differ in their propensity to think analytically. PMID:22481051
Risk prioritisation using the analytic hierarchy process
NASA Astrophysics Data System (ADS)
Sum, Rabihah Md.
2015-12-01
This study demonstrated how to use the Analytic Hierarchy Process (AHP) to prioritise risks of an insurance company. AHP is a technique to structure complex problems by arranging elements of the problems in a hierarchy, assigning numerical values to subjective judgements on the relative importance of the elements and synthesizing the judgements to determine which elements have the highest priority. The study is motivated by wide application of AHP as a prioritisation technique in complex problems. It aims to show AHP is able to minimise some limitations of risk assessment technique using likelihood and impact. The study shows AHP is able to provide consistency check on subjective judgements, organise a large number of risks into a structured framework, assist risk managers to make explicit risk trade-offs, and provide an easy to understand and systematic risk assessment process.
Phase transition in the assignment problem for random matrices
NASA Astrophysics Data System (ADS)
Esteve, J. G.; Falceto, F.
2005-12-01
We report an analytic and numerical study of a phase transition in a P problem (the assignment problem) that separates two phases whose representatives are the simple matching problem (an easy P problem) and the traveling-salesman problem (a NP-complete problem). Like other phase transitions found in combinatoric problems (K-satisfiability, number partitioning) this can help to understand the nature of the difficulties in solving NP problems an to find more accurate algorithms for them.
Robot, computer problem solving system
NASA Technical Reports Server (NTRS)
Becker, J. D.; Merriam, E. W.
1973-01-01
The TENEX computer system, the ARPA network, and computer language design technology was applied to support the complex system programs. By combining the pragmatic and theoretical aspects of robot development, an approach is created which is grounded in realism, but which also has at its disposal the power that comes from looking at complex problems from an abstract analytical point of view.
ERIC Educational Resources Information Center
Demana, Franklin; Waits, Bert K.
1993-01-01
Discusses solutions to real-world linear particle-motion problems using graphing calculators to simulate the motion and traditional analytic methods of calculus. Applications include (1) changing circular or curvilinear motion into linear motion and (2) linear particle accelerators in physics. (MDH)
Analytical characterisation of homoeopathic mother tinctures.
Biber, A; Franck-Karl, G; Waimer, F; Riegert, U; Wiget, R
2009-03-01
Quality of homoeopathic mother tinctures is assured by the definition of the starting material, the manufacturing process and the analytical characteristics described in the monograph. Traditionally analytical characterisation of the mother tincture comprises appearance, odour, identity, density and dry residue. According to annex I of directive 2001/83/EC an assay is only performed in case of a health hazard due to toxic compounds. The concept of marker substances as usually used in phytotherapy cannot be transferred to mother tinctures without research effort. For example the marker substances echinacoside, apigenin-7-glucoside and rosmarinic acid found in dried underground parts of Echinacea pallida Nutt., dried flower heads of Matricaria recutita L. and dried herb of Pulmonaria officinalis L. cannot be found in homoeopathic mother tinctures prepared from fresh material thereof. PMID:19275866
An analytical model of memristors in plants
Markin, Vladislav S; Volkov, Alexander G; Chua, Leon
2014-01-01
The memristor, a resistor with memory, was postulated by Chua in 1971 and the first solid-state memristor was built in 2008. Recently, we found memristors in vivo in plants. Here we propose a simple analytical model of 2 types of memristors that can be found within plants. The electrostimulation of plants by bipolar periodic waves induces electrical responses in the Aloe vera and Mimosa pudica with fingerprints of memristors. Memristive properties of the Aloe vera and Mimosa pudica are linked to the properties of voltage gated K+ ion channels. The potassium channel blocker TEACl transform plant memristors to conventional resistors. The analytical model of a memristor with a capacitor connected in parallel exhibits different characteristic behavior at low and high frequency of applied voltage, which is the same as experimental data obtained by cyclic voltammetry in vivo. PMID:25482769
What makes us think? A three-stage dual-process model of analytic engagement.
Pennycook, Gordon; Fugelsang, Jonathan A; Koehler, Derek J
2015-08-01
The distinction between intuitive and analytic thinking is common in psychology. However, while often being quite clear on the characteristics of the two processes ('Type 1' processes are fast, autonomous, intuitive, etc. and 'Type 2' processes are slow, deliberative, analytic, etc.), dual-process theorists have been heavily criticized for being unclear on the factors that determine when an individual will think analytically or rely on their intuition. We address this issue by introducing a three-stage model that elucidates the bottom-up factors that cause individuals to engage Type 2 processing. According to the model, multiple Type 1 processes may be cued by a stimulus (Stage 1), leading to the potential for conflict detection (Stage 2). If successful, conflict detection leads to Type 2 processing (Stage 3), which may take the form of rationalization (i.e., the Type 1 output is verified post hoc) or decoupling (i.e., the Type 1 output is falsified). We tested key aspects of the model using a novel base-rate task where stereotypes and base-rate probabilities cued the same (non-conflict problems) or different (conflict problems) responses about group membership. Our results support two key predictions derived from the model: (1) conflict detection and decoupling are dissociable sources of Type 2 processing and (2) conflict detection sometimes fails. We argue that considering the potential stages of reasoning allows us to distinguish early (conflict detection) and late (decoupling) sources of analytic thought. Errors may occur at both stages and, as a consequence, bias arises from both conflict monitoring and decoupling failures. PMID:26091582
NASA Astrophysics Data System (ADS)
Giacobbi, Dana B.; Rinaldi, Stephanie; Semler, Christian; Païdoussis, Michael P.
2012-04-01
This paper investigates the dynamics of a slender, flexible, aspirating cantilevered pipe, ingesting fluid at its free end and conveying it towards its clamped end. The problem is interesting not only from a fundamental perspective, but also because applications exist, notably in ocean mining. First, the need for the present work is demonstrated through a review of previous research into the topic - spanning many years and yielding often contradictory results - most recently suggesting that the system loses stability by flutter at relatively low flow velocities. In the present paper, that conclusion is refined and expanded upon by exploring the problem in three ways: experimentally, numerically and analytically. First, air-flow experiments were conducted using different elastomer pipes and intake shapes, in which the flow velocity of the fluid was varied and the frequency and amplitude of oscillation of the pipe were measured. Second, a fully coupled Computational Fluid Dynamics (CFD) and Computational Structural Mechanics (CSM) model was developed in ANSYS™ in order to simulate experiments and corroborate experimental results. Finally, using a Newtonian analytical approach, a new linear equation of motion describing the system was derived, and then solved via the Galerkin method in order to determine its stability characteristics. Heavily influenced by the CFD analysis, the proposed analytical model is different from previous ones, most notably because of the inclusion of a two-part fluid depressurisation at the intake. In general, both the actual and numerical experiments suggest a first-mode loss of stability by flutter at flow velocities comparable to those for the discharging case, which agrees with the results from the new analytical model.
... our e-newsletter! Aging & Health A to Z Balance Problems Basic Facts & Information What are Balance Problems? Having good balance means being able to ... Only then can you “keep your balance.” Why Balance is Important Your feelings of dizziness may last ...
ERIC Educational Resources Information Center
Foster, Colin
2012-01-01
This is the story of a real problem, not a problem that is contrived, or invented for the convenience of the appropriate planning tool. This activity by a group of students, defined simply as "8FN", might be likened to an "end of term concert". If you just happened to be a delegate at the ATM Conference 2003 you might remember the analogy. Social…
Perspectives on the future of analytical mass spectrometry
Basic, C.; Freeman, J.A.; Yost, R.A. )
1990-11-01
Unlike the secrecy of the early scientists of Oak Ridge, the free exchange of ideas between scientists at the 43rd Annual Summer Symposium on Analytical Chemistry led to the open discussion of new areas of instrumental development, new interfacing techniques, and increasingly challenging analytical problems. Chief among these challenges is the search for improved methods of analysis of high molecular weight species as questions of biochemical concern enter the realm of analytical MS (mass spectrometry). Furthermore, increasing attention is being focused on the use of chemical reactions in both the gas and solution phases to enhance the analytical capabilities of MS. By highlighting the interests of young mass spectrometrists, the symposium organizers succeeded not only in presenting the future areas of research in analytical MS but in introducing the people who will be pursuing these directives.
Hanford transuranic analytical capability
McVey, C.B.
1995-02-24
With the current DOE focus on ER/WM programs, an increase in the quantity of waste samples that requires detailed analysis is forecasted. One of the prime areas of growth is the demand for DOE environmental protocol analyses of TRU waste samples. Currently there is no laboratory capacity to support analysis of TRU waste samples in excess of 200 nCi/gm. This study recommends that an interim solution be undertaken to provide these services. By adding two glove boxes in room 11A of 222S the interim waste analytical needs can be met for a period of four to five years or until a front end facility is erected at or near the 222-S facility. The yearly average of samples is projected to be approximately 600 samples. The figure has changed significantly due to budget changes and has been downgraded from 10,000 samples to the 600 level. Until these budget and sample projection changes become firmer, a long term option is not recommended at this time. A revision to this document is recommended by March 1996 to review the long term option and sample projections.
Analytics for Metabolic Engineering
Petzold, Christopher J.; Chan, Leanne Jade G.; Nhan, Melissa; Adams, Paul D.
2015-01-01
Realizing the promise of metabolic engineering has been slowed by challenges related to moving beyond proof-of-concept examples to robust and economically viable systems. Key to advancing metabolic engineering beyond trial-and-error research is access to parts with well-defined performance metrics that can be readily applied in vastly different contexts with predictable effects. As the field now stands, research depends greatly on analytical tools that assay target molecules, transcripts, proteins, and metabolites across different hosts and pathways. Screening technologies yield specific information for many thousands of strain variants, while deep omics analysis provides a systems-level view of the cell factory. Efforts focused on a combination of these analyses yield quantitative information of dynamic processes between parts and the host chassis that drive the next engineering steps. Overall, the data generated from these types of assays aid better decision-making at the design and strain construction stages to speed progress in metabolic engineering research. PMID:26442249
[Behavior analytic approach to Asperger syndrome].
Haramaki, Shigeru; Bondy, Andy
2007-03-01
We describe the behavior analytic approach to helping people with Asperger syndrome regarding social interaction and communication issues. In the behavior analytic approach, the cause of maladaptive behavior is not attributed to the disability itself. Maladaptive behaviors are viewed as a function of the interaction between an individual and the environment. Therefore, we assess these functional relationships and intervene by modifying aspects of the environment. Functional assessment is one of the most effective methods to evaluate the cause of problem behaviors and helps in the selection of an intervention strategy. We teach students functionally equivalent alternative behaviors that are socially appropriate and yet met the needs of the individual. Furthermore, we discuss the importance of teaching individuals with Asperger syndrome critical skills, including communication skills, self-management skills, and how to deal with anxiety. PMID:17354569
Comparison of finite-difference and analytic microwave calculation methods
Friedlander, F.I.; Jackson, H.W.; Barmatz, M.; Wagner, P.
1996-12-31
Normal modes and power absorption distributions in microwave cavities containing lossy dielectric samples were calculated for problems of interest in materials processing. The calculations were performed both using a commercially available finite-difference electromagnetic solver and by numerical evaluation of exact analytic expressions. Results obtained by the two methods applied to identical physical situations were compared. The studies validate the accuracy of the finite-difference electromagnetic solver. Relative advantages of the analytic and finite-difference methods are discussed.
Existence and uniqueness of analytic solution for unsteady crystals with zero surface tension
NASA Astrophysics Data System (ADS)
Xie, Xuming
2007-03-01
We study the initial value problem for two-dimensional dendritic crystal growth with zero surface tension. If the initial data is analytic and close to Ivantsov steady solution, it is proved that unique analytic solution exists locally in time. The analysis is based on a Nirenberg Theorem on abstract Cauchy-Kovalevsky problem in properly chosen Banach spaces.
Analytic solutions of an unclassified artifact /
Trent, Bruce C.
2012-03-01
This report provides the technical detail for analytic solutions for the inner and outer profiles of the unclassified CMM Test Artifact (LANL Part Number 157Y-700373, 5/03/2001) in terms of radius and polar angle. Furthermore, analytic solutions are derived for the legacy Sheffield measurement hardware, also in terms of radius and polar angle, using part coordinates, i.e., relative to the analytic profile solutions obtained. The purpose of this work is to determine the exact solution for the “cosine correction” term inherent to measurement with the Sheffield hardware. The cosine correction is required in order to interpret the actual measurements taken by the hardware in terms of an actual part definition, or “knot-point spline definition,” that typically accompanies a component drawing. Specifically, there are two portions of the problem: first an analytic solution must be obtained for any point on the part, e.g., given the radii and the straight lines that define the part, it is required to find an exact solution for the inner and outer profile for any arbitrary polar angle. Next, the problem of the inspection of this part must be solved, i.e., given an arbitrary sphere (representing the inspection hardware) that comes in contact with the part (inner and outer profiles) at any arbitrary polar angle, it is required to determine the exact location of that intersection. This is trivial for the case of concentric circles. In the present case, however, the spherical portion of the profiles is offset from the defined center of the part, making the analysis nontrivial. Here, a simultaneous solution of the part profiles and the sphere was obtained.
NASA Astrophysics Data System (ADS)
Harper, Kathleen A.; Etkina, Eugenia
2002-10-01
As part of weekly reports,1 structured journals in which students answer three standard questions each week, they respond to the prompt, If I were the instructor, what questions would I ask or problems assign to determine if my students understood the material? An initial analysis of the results shows that some student-generated problems indicate fundamental misunderstandings of basic physical concepts. A further investigation explores the relevance of the problems to the week's material, whether the problems are solvable, and the type of problems (conceptual or calculation-based) written. Also, possible links between various characteristics of the problems and conceptual achievement are being explored. The results of this study spark many more questions for further work. A summary of current findings will be presented, along with its relationship to previous work concerning problem posing.2 1Etkina, E. Weekly Reports;A Two-Way Feedback Tool, Science Education, 84, 594-605 (2000). 2Mestre, J.P., Probing Adults Conceptual Understanding and Transfer of Learning Via Problem Posing, Journal of Applied Developmental Psychology, 23, 9-50 (2002).
Analytical Chemistry Laboratory, progress report for FY 1993
Not Available
1993-12-01
The purpose of this report is to summarize the activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for Fiscal Year (FY) 1993 (October 1992 through September 1993). This annual report is the tenth for the ACL and describes continuing effort on projects, work on new projects, and contributions of the ACL staff to various programs at ANL. The Analytical Chemistry Laboratory is a full-cost-recovery service center, with the primary mission of providing a broad range of analytical chemistry support services to the scientific and engineering programs at ANL. The ACL also has research programs in analytical chemistry, conducts instrumental and methods development, and provides analytical services for governmental, educational, and industrial organizations. The ACL handles a wide range of analytical problems. Some routine or standard analyses are done, but it is common for the Argonne programs to generate unique problems that require development or modification of methods and adaption of techniques to obtain useful analytical data. The ACL is administratively within the Chemical Technology Division (CMT), its principal ANL client, but provides technical support for many of the technical divisions and programs at ANL. The ACL has four technical groups--Chemical Analysis, Instrumental Analysis, Organic Analysis, and Environmental Analysis--which together include about 45 technical staff members. Talents and interests of staff members cross the group lines, as do many projects within the ACL.
Analytical Chemistry Laboratory. Progress report for FY 1996
Green, D.W.; Boparai, A.S.; Bowers, D.L.
1996-12-01
The purpose of this report is to summarize the activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for Fiscal Year (FY) 1996. This annual report is the thirteenth for the ACL. It describes effort on continuing and new projects and contributions of the ACL staff to various programs at ANL. The ACL operates in the ANL system as a full-cost-recovery service center, but has a mission that includes a complementary research and development component: The Analytical Chemistry Laboratory will provide high-quality, cost-effective chemical analysis and related technical support to solve research problems of our clients -- Argonne National Laboratory, the Department of Energy, and others -- and will conduct world-class research and development in analytical chemistry and its applications. Because of the diversity of research and development work at ANL, the ACL handles a wide range of analytical chemistry problems. Some routine or standard analyses are done, but the ACL usually works with commercial laboratories if our clients require high-volume, production-type analyses. It is common for ANL programs to generate unique problems that require significant development of methods and adaption of techniques to obtain useful analytical data. Thus, much of the support work done by the ACL is very similar to our applied analytical chemistry research.
Visual Analytics for Power Grid Contingency Analysis
Wong, Pak C.; Huang, Zhenyu; Chen, Yousu; Mackey, Patrick S.; Jin, Shuangshuang
2014-01-20
Contingency analysis is the process of employing different measures to model scenarios, analyze them, and then derive the best response to remove the threats. This application paper focuses on a class of contingency analysis problems found in the power grid management system. A power grid is a geographically distributed interconnected transmission network that transmits and delivers electricity from generators to end users. The power grid contingency analysis problem is increasingly important because of both the growing size of the underlying raw data that need to be analyzed and the urgency to deliver working solutions in an aggressive timeframe. Failure to do so may bring significant financial, economic, and security impacts to all parties involved and the society at large. The paper presents a scalable visual analytics pipeline that transforms about 100 million contingency scenarios to a manageable size and form for grid operators to examine different scenarios and come up with preventive or mitigation strategies to address the problems in a predictive and timely manner. Great attention is given to the computational scalability, information scalability, visual scalability, and display scalability issues surrounding the data analytics pipeline. Most of the large-scale computation requirements of our work are conducted on a Cray XMT multi-threaded parallel computer. The paper demonstrates a number of examples using western North American power grid models and data.
Analytical laboratory quality audits
Kelley, William D.
2001-06-11
Analytical Laboratory Quality Audits are designed to improve laboratory performance. The success of the audit, as for many activities, is based on adequate preparation, precise performance, well documented and insightful reporting, and productive follow-up. Adequate preparation starts with definition of the purpose, scope, and authority for the audit and the primary standards against which the laboratory quality program will be tested. The scope and technical processes involved lead to determining the needed audit team resources. Contact is made with the auditee and a formal audit plan is developed, approved and sent to the auditee laboratory management. Review of the auditee's quality manual, key procedures and historical information during preparation leads to better checklist development and more efficient and effective use of the limited time for data gathering during the audit itself. The audit begins with the opening meeting that sets the stage for the interactions between the audit team and the laboratory staff. Arrangements are worked out for the necessary interviews and examination of processes and records. The information developed during the audit is recorded on the checklists. Laboratory management is kept informed of issues during the audit so there are no surprises at the closing meeting. The audit report documents whether the management control systems are effective. In addition to findings of nonconformance, positive reinforcement of exemplary practices provides balance and fairness. Audit closure begins with receipt and evaluation of proposed corrective actions from the nonconformances identified in the audit report. After corrective actions are accepted, their implementation is verified. Upon closure of the corrective actions, the audit is officially closed.
NASA Technical Reports Server (NTRS)
Wang, Xiao-Yen; Himansu, Ananda; Chang, Sin-Chung; Jorgenson, Philip C. E.
2000-01-01
The Internal Propagation problems, Fan Noise problem, and Turbomachinery Noise problems are solved using the space-time conservation element and solution element (CE/SE) method. The problems in internal propagation problems address the propagation of sound waves through a nozzle. Both the nonlinear and linear quasi 1D Euler equations are solved. Numerical solutions are presented and compared with the analytical solution. The fan noise problem concerns the effect of the sweep angle on the acoustic field generated by the interaction of a convected gust with a cascade of 3D flat plates. A parallel version of the 3D CE/SE Euler solver is developed and employed to obtain numerical solutions for a family of swept flat plates. Numerical solutions for sweep angles of 0, 5, 10, and 15 deg are presented. The turbomachinery problems describe the interaction of a 2D vortical gust with a cascade of flat-plate airfoils with/without a downstream moving grid. The 2D nonlinear Euler Equations are solved and the converged numerical solutions are presented and compared with the corresponding analytical solution. All the comparisons demonstrate that the CE/SE method is capable of solving aeroacoustic problems with/without shock waves in a simple and efficient manner. Furthermore, the simple non-reflecting boundary condition used in the CE/SE method which is not based on the characteristic theory works very well in 1D, 2D and 3D problems.
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Response and characteristics of structures subjected to S-H waves
NASA Technical Reports Server (NTRS)
Wu, S. T.
1984-01-01
A study of the dynamic characteristics of a coupled translational-rotational system is given. The formulation of the problem considers the soil-structure interaction effects by utilizing the impedance functions at the foundation of a structure. Due to the fact that the coefficient matrix in the characteristic equation is frequency dependent in nature, iterations have to be performed to find the nature frequencies of the system. Examples and discussions are presented. Comparisons of the analytical results from various approaches are also given.
NASA Technical Reports Server (NTRS)
Podhorodeski, R. P.; Fenton, R. G.; Goldenberg, A. A.
1989-01-01
Using a method based upon resolving joint velocities using reciprocal screw quantities, compact analytical expressions are generated for the inverse solution of the joint rates of a seven revolute (spherical-revolute-spherical) manipulator. The method uses a sequential decomposition of screw coordinates to identify reciprocal screw quantities used in the resolution of a particular joint rate solution, and also to identify a Jacobian null-space basis used for the direct solution of optimal joint rates. The results of the screw decomposition are used to study special configurations of the manipulator, generating expressions for the inverse velocity solution for all non-singular configurations of the manipulator, and identifying singular configurations and their characteristics. Two functions are therefore served: a new general method for the solution of the inverse velocity problem is presented; and complete analytical expressions are derived for the resolution of the joint rates of a seven degree of freedom manipulator useful for telerobotic and industrial robotic application.
Das, Siddhartha; Subramanian, Kapil; Chakraborty, Suman
2007-08-01
In this paper, a generalized surface-kinetics based model is developed to analytically investigate the influences of the substrate types and the buffer compositions on the macromolecular transport and hybridization in microfluidic channels, under electrokinetic influences. For specific illustration, three typical microchannel substrates, namely silanized glass, polycarbonate and PDMS, are considered, in order to obtain analytical expressions for their zeta potentials as a function of the buffer pH and the substrate compositions. The expressions for the zeta potential are subsequently employed to derive the respective velocity distributions, under the application of electric fields of identical strengths in all cases. It is also taken into consideration that the charged macromolecules introduced into these channels are subjected to electrophoretic influences on account of the applied electric fields. Closed form expressions are derived to predict the transport behaviour of the macromolecules and their subsequent hybridization characteristics. From the analysis presented, it is shown that the modification of the channel surface with silane-treatment becomes useful for enhancing the macromolecular transport and surface hybridization, only if the buffer pH permits a large surface charge density. The analytical solutions are also compared with full-scale numerical solutions of the coupled problem of fluid dynamic and macromolecular transport in presence of the pertinent surface reactions, in order to justify the effectiveness of closed-form expressions derived in this study. PMID:17481862
The Case for Assessment Analytics
ERIC Educational Resources Information Center
Ellis, Cath
2013-01-01
Learning analytics is a relatively new field of inquiry and its precise meaning is both contested and fluid (Johnson, Smith, Willis, Levine & Haywood, 2011; LAK, n.d.). Ferguson (2012) suggests that the best working definition is that offered by the first Learning Analytics and Knowledge (LAK) conference: "the measurement, collection,…
Understanding Education Involving Geovisual Analytics
ERIC Educational Resources Information Center
Stenliden, Linnea
2013-01-01
Handling the vast amounts of data and information available in contemporary society is a challenge. Geovisual Analytics provides technology designed to increase the effectiveness of information interpretation and analytical task solving. To date, little attention has been paid to the role such tools can play in education and to the extent to which…
Analytical analysis of particle-core dynamics
Batygin, Yuri K
2010-01-01
Particle-core interaction is a well-developed model of halo formation in high-intensity beams. In this paper, we present an analytical solution for averaged, single particle dynamics, around a uniformly charged beam. The problem is analyzed through a sequence of canonical transformations of the Hamiltonian, which describes nonlinear particle oscillations. A closed form expression for maximum particle deviation from the axis is obtained. The results of this study are in good agreement with numerical simulations and with previously obtained data.
NASA Astrophysics Data System (ADS)
Ahn, Hojin
1989-12-01
Granular materials flowing down an inclined chute were studied experimentally and analytically. Characteristics of convective heat transfer to granular flows were also investigated experimentally and numerically. Experiments on continuous, steady flows of granular materials in an inclined chute were conducted with the objectives of understanding the characteristics of chute flows and of acquiring information on the rheological behavior of granular material flow. Existing constitutive equations and governing equations were used to solve for fully developed chute flows of granular materials, and thus the boundary value problem was formulated with two parameters (the coefficient of restitution between particles, and the chute inclination) and three boundary values at the chute base wall (the values of solid fraction, granular temperature, and mean velocity at the wall). The boundary value problem was numerically solved by the shooting method. These analytical results were also compared with the present experimental values and with the computer simulations by other investigators in their literature. Experiments on heat transfer to granular flows over a flat heating plate were conducted with three sizes of glass beads, polystyrene beads, and mustard seeds. A modification on the existing model for the convective heat transfer was made using the effective Nusselt number and the effective Peclet number, which include the effects of solid fraction variations. The slightly modified model could describe the heat transfer characteristics of both fast and slow flows (supercritical and subcritical). A numerical analysis of the transfer to granular flows was also performed. The results were compared with the present experimental data, and reasonable agreement was found in the comparison.
[Critical reading of analytical observational studies].
García Villar, C; Marín León, I
2015-11-01
Analytical observational studies provide very important information about real-life clinical practice and the natural history of diseases and can suggest causality. Furthermore, they are very common in scientific journals. The aim of this article is to review the main concepts necessary for the critical reading of articles about radiological studies with observational designs. It reviews the characteristics that case-control and cohort studies must have to ensure high quality. It explains a method of critical reading that involves checking the attributes that should be evaluated in each type of article using a structured list of specific questions. It underlines the main characteristics that confer credibility and confidence on the article evaluated. Readers are provided with tools for the critical analysis of the observational studies published in scientific journals. PMID:26123855
Aptamers: molecular tools for analytical applications.
Mairal, Teresa; Ozalp, Veli Cengiz; Lozano Sánchez, Pablo; Mir, Mònica; Katakis, Ioanis; O'Sullivan, Ciara K
2008-02-01
Aptamers are artificial nucleic acid ligands, specifically generated against certain targets, such as amino acids, drugs, proteins or other molecules. In nature they exist as a nucleic acid based genetic regulatory element called a riboswitch. For generation of artificial ligands, they are isolated from combinatorial libraries of synthetic nucleic acid by exponential enrichment, via an in vitro iterative process of adsorption, recovery and reamplification known as systematic evolution of ligands by exponential enrichment (SELEX). Thanks to their unique characteristics and chemical structure, aptamers offer themselves as ideal candidates for use in analytical devices and techniques. Recent progress in the aptamer selection and incorporation of aptamers into molecular beacon structures will ensure the application of aptamers for functional and quantitative proteomics and high-throughput screening for drug discovery, as well as in various analytical applications. The properties of aptamers as well as recent developments in improved, time-efficient methods for their selection and stabilization are outlined. The use of these powerful molecular tools for analysis and the advantages they offer over existing affinity biocomponents are discussed. Finally the evolving use of aptamers in specific analytical applications such as chromatography, ELISA-type assays, biosensors and affinity PCR as well as current avenues of research and future perspectives conclude this review. PMID:17581746
The Students Decision Making in Solving Discount Problem
ERIC Educational Resources Information Center
Abdillah; Nusantara, Toto; Subanji; Susanto, Hery; Abadyo
2016-01-01
This research is reviewing students' process of decision making intuitively, analytically, and interactively. The research done by using discount problem which specially created to explore student's intuition, analytically, and interactively. In solving discount problems, researcher exploring student's decision in determining their attitude which…
Analytical study on mesocarbon microbeads derived from coal tar pitch
Zhang, Y.; Murata, S.; Nomura, M.
1999-07-01
Pitches have been recognized as excellent precursors for carbon materials and their properties are considered to be influential on the properties and function of carbon material. For this reason, their detailed characterization is being required. Successful pitch characterization must satisfy the following points: (1) very complicated pitches can be clearly distinguished; (2) the performance of the final carbon product can be predicted by characterizing the precursor pitch at its molecular level; and (3) a satisfactory explanation can be provided for chemical and physical behavior of pitches for a given utilization process based on their structural differences. Successful pitch characterization is quite difficult to be attained because pitches are very complex mixtures containing several hundred compounds with different functionalities. Thus, the methods for their characterization are limited to the measurements of average structural parameters, such as softening point (SP), H/C atomic ratio, quinoline- and toluene-insoluble (QI and TI) fractions, aromaticity, carbon yield, etc.. Although these parameters can give a fairly good evaluation about pitch quality, they can not always explain why pitches with similar characteristics on traditional characterization techniques display a significantly different behavior. This fact provides a challenging subject in the field of pitch characterization. At the same time, there is a possibility that in a given case satisfactory important factors remain undetected due to the limitation of analytical techniques, thus leading to serious problems in the pitch utilization. Therefore, it seems to be essential to know, for a given utilization of pitches, which of the pitch properties normally measured is important and how this affects the behavior of pitch. Another serious difficulty in pitch characterization is the fact that pitches are normally not completely soluble in solvents. There is no single analytical technique which can
Statistically qualified neuro-analytic failure detection method and system
Vilim, Richard B.; Garcia, Humberto E.; Chen, Frederick W.
2002-03-02
An apparatus and method for monitoring a process involve development and application of a statistically qualified neuro-analytic (SQNA) model to accurately and reliably identify process change. The development of the SQNA model is accomplished in two stages: deterministic model adaption and stochastic model modification of the deterministic model adaptation. Deterministic model adaption involves formulating an analytic model of the process representing known process characteristics, augmenting the analytic model with a neural network that captures unknown process characteristics, and training the resulting neuro-analytic model by adjusting the neural network weights according to a unique scaled equation error minimization technique. Stochastic model modification involves qualifying any remaining uncertainty in the trained neuro-analytic model by formulating a likelihood function, given an error propagation equation, for computing the probability that the neuro-analytic model generates measured process output. Preferably, the developed SQNA model is validated using known sequential probability ratio tests and applied to the process as an on-line monitoring system. Illustrative of the method and apparatus, the method is applied to a peristaltic pump system.
The Science of Analytic Reporting
Chinchor, Nancy; Pike, William A.
2009-09-23
The challenge of visually communicating analysis results is central to the ability of visual analytics tools to support decision making and knowledge construction. The benefit of emerging visual methods will be improved through more effective exchange of the insights generated through the use of visual analytics. This paper outlines the major requirements for next-generation reporting systems in terms of eight major research needs: the development of best practices, design automation, visual rhetoric, context and audience, connecting analysis to presentation, evidence and argument, collaborative environments, and interactive and dynamic documents. It also describes an emerging technology called Active Products that introduces new techniques for analytic process capture and dissemination.
ANALYTICAL STAR FORMATION RATE FROM GRAVOTURBULENT FRAGMENTATION
Hennebelle, Patrick; Chabrier, Gilles
2011-12-20
We present an analytical determination of the star formation rate (SFR) in molecular clouds, based on a time-dependent extension of our analytical theory of the stellar initial mass function. The theory yields SFRs in good agreement with observations, suggesting that turbulence is the dominant, initial process responsible for star formation. In contrast to previous SFR theories, the present one does not invoke an ad hoc density threshold for star formation; instead, the SFR continuously increases with gas density, naturally yielding two different characteristic regimes, thus two different slopes in the SFR versus gas density relationship, in agreement with observational determinations. Besides the complete SFR derivation, we also provide a simplified expression, which reproduces the complete calculations reasonably well and can easily be used for quick determinations of SFRs in cloud environments. A key property at the heart of both our complete and simplified theory is that the SFR involves a density-dependent dynamical time, characteristic of each collapsing (prestellar) overdense region in the cloud, instead of one single mean or critical freefall timescale. Unfortunately, the SFR also depends on some ill-determined parameters, such as the core-to-star mass conversion efficiency and the crossing timescale. Although we provide estimates for these parameters, their uncertainty hampers a precise quantitative determination of the SFR, within less than a factor of a few.
Musielak, Z E; Quarles, B
2014-06-01
The three-body problem, which describes three masses interacting through Newtonian gravity without any restrictions imposed on the initial positions and velocities of these masses, has attracted the attention of many scientists for more than 300 years. In this paper, we present a review of the three-body problem in the context of both historical and modern developments. We describe the general and restricted (circular and elliptic) three-body problems, different analytical and numerical methods of finding solutions, methods for performing stability analysis and searching for periodic orbits and resonances. We apply the results to some interesting problems of celestial mechanics. We also provide a brief presentation of the general and restricted relativistic three-body problems, and discuss their astronomical applications. PMID:24913140
Surface crack problems in plates
NASA Technical Reports Server (NTRS)
Joseph, P. F.; Erdogan, F.
1989-01-01
The mode I crack problem in plates under membrane loading and bending is reconsidered. The purpose is to examine certain analytical features of the problem further and to provide some new results. The formulation and the results given by the classical and the Reissner plate theories for through and part-through cracks are compared. For surface cracks the three-dimensional finite element solution is used as the basis of comparison. The solution is obtained and results are given for the crack/contact problem in a plate with a through crack under pure bending and for the crack interaction problem. Also, a procedure is developed to treat the problem of subcritical crack growth and to trace the evolution of the propagating crack.
ERIC Educational Resources Information Center
Murphy, Pat, Ed.
1993-01-01
"Exploring" is a magazine of science, art, and human perception, produced by Exploratorium in collaboration with other participating museums. This issue focuses on puzzles and problem solving. Brain teasers, puzzles, and the strategies for solving them are included. Features include: (1) "Homework Assignment #3" (Paul Doherty); (2) "The Case of…
ERIC Educational Resources Information Center
Connors, G. Patrick
Heat problems and heat cramps related to jogging can be caused by fluid imbalances, medications, dietary insufficiency, vomiting or diarrhea, among other factors. If the condition keeps reoccurring, the advice of a physician should be sought. Some preventive measures that can be taken include: (1) running during the cooler hours of the day; (2)…
Analytic representation of the Dirac equation
NASA Astrophysics Data System (ADS)
Gill, Tepper L.; Zachary, W. W.; Alfred, Marcus
2005-08-01
In this paper, we construct an analytical separation (diagonalization) of the full (minimal coupling) Dirac equation into particle and antiparticle components. The diagonalization is analytic in that it is achieved without transforming the wavefunctions, as is done by the Foldy-Wouthuysen method, and reveals the nonlocal time behaviour of the particle-antiparticle relationship. We then show explicitly that the Pauli equation is not completely valid for the study of the Dirac hydrogen atom problem in s-states (hyperfine splitting). We conclude that there are some open mathematical problems with any attempt to explicitly show that the Dirac equation is insufficient to explain the full hydrogen spectrum. If the perturbation method can be justified, our analysis suggests that the use of cut-offs in QED is already justified by the eigenvalue analysis that supports it. Using a new method, we are able to effect separation of variables for full coupling, solve the radial equation and provide graphs of the probability density function for the 2p- and 2s-states, and compare them with those of the Dirac-Coulomb case.
Trends in Analytical Scale Separations.
ERIC Educational Resources Information Center
Jorgenson, James W.
1984-01-01
Discusses recent developments in the instrumentation and practice of analytical scale operations. Emphasizes detection devices and procedures in gas chromatography, liquid chromatography, electrophoresis, supercritical fluid chromatography, and field-flow fractionation. (JN)
Liposomes: Technologies and Analytical Applications
NASA Astrophysics Data System (ADS)
Jesorka, Aldo; Orwar, Owe
2008-07-01
Liposomes are structurally and functionally some of the most versatile supramolecular assemblies in existence. Since the beginning of active research on lipid vesicles in 1965, the field has progressed enormously and applications are well established in several areas, such as drug and gene delivery. In the analytical sciences, liposomes serve a dual purpose: Either they are analytes, typically in quality-assessment procedures of liposome preparations, or they are functional components in a variety of new analytical systems. Liposome immunoassays, for example, benefit greatly from the amplification provided by encapsulated markers, and nanotube-interconnected liposome networks have emerged as ultrasmall-scale analytical devices. This review provides information about new developments in some of the most actively researched liposome-related topics.
Laboratory Workhorse: The Analytical Balance.
ERIC Educational Resources Information Center
Clark, Douglas W.
1979-01-01
This report explains the importance of various analytical balances in the water or wastewater laboratory. Stressed is the proper procedure for utilizing the equipment as well as the mechanics involved in its operation. (CS)
Analytic Methods in Investigative Geometry.
ERIC Educational Resources Information Center
Dobbs, David E.
2001-01-01
Suggests an alternative proof by analytic methods, which is more accessible than rigorous proof based on Euclid's Elements, in which students need only apply standard methods of trigonometry to the data without introducing new points or lines. (KHR)
Analytical Chemistry: A Literary Approach.
ERIC Educational Resources Information Center
Lucy, Charles A.
2000-01-01
Provides an anthology of references to descriptions of analytical chemistry techniques from history, popular fiction, and film which can be used to capture student interest and frame discussions of chemical techniques. (WRM)
Cautions Concerning Electronic Analytical Balances.
ERIC Educational Resources Information Center
Johnson, Bruce B.; Wells, John D.
1986-01-01
Cautions chemists to be wary of ferromagnetic samples (especially magnetized samples), stray electromagnetic radiation, dusty environments, and changing weather conditions. These and other conditions may alter readings obtained from electronic analytical balances. (JN)
Chiampi, M.; Repetto, M.; Chiarabaglio, D.
1995-11-01
The hysteresis phenomenon can significantly affect the behavior of magnetic cores in electrical machines and devices. This paper presents a finite element solution of periodic steady state magnetic field problems in soft materials with scalar hysteresis. The Jiles-Atherton model is employed for the generation of symmetric B-H loops and it is coupled with the Fixed Point Technique for handling magnetic nonlinearities. The proposed procedure is applied to a hysteretic model problem whose analytical solution is available. The results show that the Fixed Point Technique can efficiently deal with non-single valued material characteristics under periodic operating conditions.
Analytical Model of Nano-Electromechanical (NEM) Nonvolatile Memory Cells
NASA Astrophysics Data System (ADS)
Han, Boram; Choi, Woo Young
The fringe field effects of nano-electromechanical (NEM) nonvolatile memory cells have been investigated analytically for the accurate evaluation of NEM memory cells. As the beam width is scaled down, fringe field effect becomes more severe. It has been observed that pull-in, release and hysteresis voltage decrease more than our prediction. Also, the fringe field on cell characteristics has been discussed.
Individual Development and Latent Groups: Analytical Tools for Interpreting Heterogeneity
ERIC Educational Resources Information Center
Thomas, H.; Dahlin, M.P.
2005-01-01
Individual differences in development or growth are typically handled under conventional analytical approaches by blocking on the variables thought to contribute to variation, such as sex or age. But such approaches fail when the differences are attributable to latent characteristics (i.e., variables not directly observable beforehand) within the…
An analytic solution for the J2 perturbed equatorial orbit
NASA Technical Reports Server (NTRS)
Jezewski, D. J.
1983-01-01
An analytic solution for the J2 perturbed equatorial orbit is obtained in terms of elliptic functions and integrals. The necessary equations for computing the position and elocity vectors, and the time are given in terms of known functions. The perturbed periapsis and apoapsis distances are determined from the roots of a characteristic cubic.
Functionalized magnetic nanoparticle analyte sensor
Yantasee, Wassana; Warner, Maryin G; Warner, Cynthia L; Addleman, Raymond S; Fryxell, Glen E; Timchalk, Charles; Toloczko, Mychailo B
2014-03-25
A method and system for simply and efficiently determining quantities of a preselected material in a particular solution by the placement of at least one superparamagnetic nanoparticle having a specified functionalized organic material connected thereto into a particular sample solution, wherein preselected analytes attach to the functionalized organic groups, these superparamagnetic nanoparticles are then collected at a collection site and analyzed for the presence of a particular analyte.
Visual Analytics Technology Transition Progress
Scholtz, Jean; Cook, Kristin A.; Whiting, Mark A.; Lemon, Douglas K.; Greenblatt, Howard
2009-09-23
The authors provide a description of the transition process for visual analytic tools and contrast this with the transition process for more traditional software tools. This paper takes this into account and describes a user-oriented approach to technology transition including a discussion of key factors that should be considered and adapted to each situation. The progress made in transitioning visual analytic tools in the past five years is described and the challenges that remain are enumerated.
Applications of the Analytical Electron Microscope to Materials Science
NASA Technical Reports Server (NTRS)
Goldstein, J. I.
1992-01-01
In the last 20 years, the analytical electron microscope (AEM) as allowed investigators to obtain chemical and structural information from less than 50 nanometer diameter regions in thin samples of materials and to explore problems where reactions occur at boundaries and interfaces or within small particles or phases in bulk samples. Examples of the application of the AEM to materials science problems are presented in this paper and demonstrate the usefulness and the future potential of this instrument.
ARPEFS as an analytic technique
Schach von Wittenau, A.E.
1991-04-01
Two modifications to the ARPEFS technique are introduced. These are studied using p(2 {times} 2)S/Cu(001) as a model system. The first modification is the obtaining of ARPEFS {chi}(k) curves at temperatures as low as our equipment will permit. While adding to the difficulty of the experiment, this modification is shown to almost double the signal-to-noise ratio of normal emission p(2 {times} 2)S/Cu(001) {chi}(k) curves. This is shown by visual comparison of the raw data and by the improved precision of the extracted structural parameters. The second change is the replacement of manual fitting of the Fourier filtered {chi}(k) curves by the use of the simplex algorithm for parameter determination. Again using p(2 {times} 2)S/Cu(001) data, this is shown to result in better agreement between experimental {chi}(k) curves and curves calculated based on model structures. The improved ARPEFS is then applied to p(2 {times} 2)S/Ni(111) and ({radical}3 {times} {radical}3) R30{degree}S/Ni(111). For p(2 {times} 2)S/Cu(001) we find a S-Cu bond length of 2.26 {Angstrom}, with the S adatom 1.31 {Angstrom} above the fourfold hollow site. The second Cu layer appears to be corrugated. Analysis of the p(2 {times} 2)S/Ni(111) data indicates that the S adatom adatom adsorbs onto the FCC threefold hollow site 1.53 {Angstrom} above the Ni surface. The S-Ni bond length is determined to be 2.13 {Angstrom}, indicating an outwards shift of the first layer Ni atoms. We are unable to assign a unique structure to ({radical}3 {times} {radical}3)R30{degree}S/Ni(111). An analysis of the strengths and weaknesses of ARPEFS as an experimental and analytic technique is presented, along with a summary of problems still to be addressed.