Exploring Partial Order of European Countries
ERIC Educational Resources Information Center
Annoni, Paola; Bruggemann, Rainer
2009-01-01
Partial Order Theory has been recently more and more employed in applied science to overcome the intrinsic disadvantage hidden in aggregation, if a multiple attribute system is available. Despite its numerous positive features, there are many practical cases where the interpretation of the partial order can be rather troublesome. In these cases…
Partial order of quantum effects
NASA Astrophysics Data System (ADS)
Lahti, Pekka J.; MaÌ§czynski, Maciej J.
1995-04-01
The set of effects is not a lattice with respect to its natural order. Projection operators do have the greatest lower bounds (and the least upper bounds) in that set, but there are also other (incomparable) effects which share this property. However, the coexistence, the commutativity, and the regularity of a pair of effects are not sufficient for the existence of their infima and suprema. The structure of the range of an observable (as a normalized POV measure) can vary from that of a commutative Boolean to a noncommutative non-Boolean subset of effects.
Pseudo Boolean Programming for Partially Ordered Genomes
NASA Astrophysics Data System (ADS)
Angibaud, Sébastien; Fertin, Guillaume; Thévenin, Annelyse; Vialette, Stéphane
Comparing genomes of different species is a crucial problem in comparative genomics. Different measures have been proposed to compare two genomes: number of common intervals, number of adjacencies, number of reversals, etc. These measures are classically used between two totally ordered genomes. However, genetic mapping techniques often give rise to different maps with some unordered genes. Starting from a partial order between genes of a genome, one method to find a total order consists in optimizing a given measure between a linear extension of this partial order and a given total order of a close and well-known genome. However, for most common measures, the problem turns out to be
Partially ordered state of ice XV.
Komatsu, K; Noritake, F; Machida, S; Sano-Furukawa, A; Hattori, T; Yamane, R; Kagi, H
2016-01-01
Most ice polymorphs have order-disorder "pairs" in terms of hydrogen positions, which contributes to the rich variety of ice polymorphs; in fact, three recently discovered polymorphs- ices XIII, XIV, and XV-are ordered counter forms to already identified disordered phases. Despite the considerable effort to understand order-disorder transition in ice crystals, there is an inconsistency among the various experiments and calculations for ice XV, the ordered counter form of ice VI, i.e., neutron diffraction observations suggest antiferroelectrically ordered structures, which disagree with dielectric measurement and theoretical studies, implying ferroelectrically ordered structures. Here we investigate in-situ neutron diffraction measurements and density functional theory calculations to revisit the structure and stability of ice XV. We find that none of the completely ordered configurations are particular favored; instead, partially ordered states are established as a mixture of ordered domains in disordered ice VI. This scenario in which several kinds of ordered configuration coexist dispels the contradictions in previous studies. It means that the order-disorder pairs in ice polymorphs are not one-to-one correspondent pairs but rather have one-to-n correspondence, where there are n possible configurations at finite temperature. PMID:27375120
Partially ordered state of ice XV
Komatsu, K.; Noritake, F.; Machida, S.; Sano-Furukawa, A.; Hattori, T.; Yamane, R.; Kagi, H.
2016-01-01
Most ice polymorphs have order–disorder “pairs” in terms of hydrogen positions, which contributes to the rich variety of ice polymorphs; in fact, three recently discovered polymorphs— ices XIII, XIV, and XV—are ordered counter forms to already identified disordered phases. Despite the considerable effort to understand order–disorder transition in ice crystals, there is an inconsistency among the various experiments and calculations for ice XV, the ordered counter form of ice VI, i.e., neutron diffraction observations suggest antiferroelectrically ordered structures, which disagree with dielectric measurement and theoretical studies, implying ferroelectrically ordered structures. Here we investigate in-situ neutron diffraction measurements and density functional theory calculations to revisit the structure and stability of ice XV. We find that none of the completely ordered configurations are particular favored; instead, partially ordered states are established as a mixture of ordered domains in disordered ice VI. This scenario in which several kinds of ordered configuration coexist dispels the contradictions in previous studies. It means that the order–disorder pairs in ice polymorphs are not one-to-one correspondent pairs but rather have one-to-n correspondence, where there are n possible configurations at finite temperature. PMID:27375120
Optimum design of a multilayer beam partially treated with magnetorheological fluid
NASA Astrophysics Data System (ADS)
Rajamohan, Vasudevan; Sedaghati, Ramin; Rakheja, Subhash
2010-06-01
The modal damping characteristics of beams partially treated with magnetorheological (MR) fluid elements are studied using the modal strain energy approach and the finite element method. Different configurations of a sandwich beam partially treated with MR fluid are considered, including a beam with a cluster of MR fluid segments and a beam with arbitrarily located MR fluid segments. The significance of the location of the MR fluid segments on the modal damping factor is investigated under different end conditions. An optimization problem is formulated by combining finite element analysis with optimization algorithms based on sequential quadratic programming (SQP) and the genetic algorithm (GA) to identify optimal locations for MR fluid treatment to achieve maximum modal damping corresponding to the first five modes of flexural vibration, individually and simultaneously. The solutions of the optimization problem revealed that the GA converges to the global solutions rapidly compared to the SQP method, which in some modal configurations usually entraps in the local optimum. The results suggest that the optimal location of the MR fluid treatment is strongly related to the end conditions and also the mode of vibration. Furthermore, partial treatments with MR fluid can significantly alter the deflection modes of the beam. It has also been demonstrated that optimal locations of the MR fluid segments based on linear combination of the modal damping factors of the first five modes are identical to those obtained based on the first mode, irrespective of the end conditions. However, the optimal locations of the MR fluid segments, identified based on the logarithmic summation of the modal damping factors of the first five modes, would yield a more uniform shear energy distribution compared to that attained by considering individual modes or a linear summation of the individual modes.
The optimum order of a Markov chain model for daily rainfall in Nigeria
NASA Astrophysics Data System (ADS)
Jimoh, O. D.; Webster, P.
1996-11-01
Markov type models are often used to describe the occurrence of daily rainfall. Although models of Order 1 have been successfully employed, there remains uncertainty concerning the optimum order for such models. This paper is concerned with estimation of the optimum order of Markov chains and, in particular, the use of objective criteria of the Akaike and Bayesian Information Criteria (AIC and BIC, respectively). Using daily rainfall series for five stations in Nigeria, it has been found that the AIC and BIC estimates vary with month as well as the value of the rainfall threshold used to define a wet day. There is no apparent system to this variation, although AIC estimates are consistently greater than or equal to BIC estimates, with values of the latter limited to zero or unity. The optimum order is also investigated through generation of synthetic sequences of wet and dry days using the transition matrices of zero-, first- and second-order Markov chains. It was found that the first-order model is superior to the zero-order model in representing the characteristics of the historical sequence as judged using frequency duration curves. There was no discernible difference between the model performance for first- and second-order models. There was no seasonal varation in the model performance, which contrasts with the optimum models identified using AIC and BIC estimates. It is concluded that caution is needed with the use of objective criteria for determining the optimum order of the Markov model and that the use of frequency duration curves can provide a robust alternative method of model identification. Comments are also made on the importance of record length and non-stationarity for model identification
Fitting optimum order of Markov chain models for daily rainfall occurrences in Peninsular Malaysia
NASA Astrophysics Data System (ADS)
Deni, Sayang Mohd; Jemain, Abdul Aziz; Ibrahim, Kamarulzaman
2009-06-01
The analysis of the daily rainfall occurrence behavior is becoming more important, particularly in water-related sectors. Many studies have identified a more comprehensive pattern of the daily rainfall behavior based on the Markov chain models. One of the aims in fitting the Markov chain models of various orders to the daily rainfall occurrence is to determine the optimum order. In this study, the optimum order of the Markov chain models for a 5-day sequence will be examined in each of the 18 rainfall stations in Peninsular Malaysia, which have been selected based on the availability of the data, using the Akaike’s (AIC) and Bayesian information criteria (BIC). The identification of the most appropriate order in describing the distribution of the wet (dry) spells for each of the rainfall stations is obtained using the Kolmogorov-Smirnov goodness-of-fit test. It is found that the optimum order varies according to the levels of threshold used (e.g., either 0.1 or 10.0 mm), the locations of the region and the types of monsoon seasons. At most stations, the Markov chain models of a higher order are found to be optimum for rainfall occurrence during the northeast monsoon season for both levels of threshold. However, it is generally found that regardless of the monsoon seasons, the first-order model is optimum for the northwestern and eastern regions of the peninsula when the level of thresholds of 10.0 mm is considered. The analysis indicates that the first order of the Markov chain model is found to be most appropriate for describing the distribution of wet spells, whereas the higher-order models are found to be adequate for the dry spells in most of the rainfall stations for both threshold levels and monsoon seasons.
The Use of Partial Order Structures for Investigating Suicidal Behavior.
ERIC Educational Resources Information Center
Dancer, L. Suzanne
This study had two purposes: to test the usefulness of partial order scalogram analysis with multivariate response data; and to illustrate the multidimensional nature of suicide risk. A detailed introduction describes partial order scalograms, which locate respondents' profiles in a two-dimensional space (rather than on a unidimensional Guttman…
First-order partial differential equations in classical dynamics
NASA Astrophysics Data System (ADS)
Smith, B. R.
2009-12-01
Carathèodory's classic work on the calculus of variations explores in depth the connection between ordinary differential equations and first-order partial differential equations. The n second-order ordinary differential equations of a classical dynamical system reduce to a single first-order differential equation in 2n independent variables. The general solution of first-order partial differential equations touches on many concepts central to graduate-level courses in analytical dynamics including the Hamiltonian, Lagrange and Poisson brackets, and the Hamilton-Jacobi equation. For all but the simplest dynamical systems the solution requires one or more of these techniques. Three elementary dynamical problems (uniform acceleration, harmonic motion, and cyclotron motion) can be solved directly from the appropriate first-order partial differential equation without the use of advanced methods. The process offers an unusual perspective on classical dynamics, which is readily accessible to intermediate students who are not yet fully conversant with advanced approaches.
Explanation-based generalization of partially ordered plans
NASA Technical Reports Server (NTRS)
Kambhampati, Subbarao; Kedar, Smadar
1991-01-01
Most previous work in analytic generalization of plans dealt with totally ordered plans. These methods cannot be directly applied to generalizing partially ordered plans, since they do not capture all interactions among plan operators for all total orders of such plans. We introduce a new method for generalizing partially ordered plans. This method is based on providing explanation-based generalization (EBG) with explanations which systematically capture the interactions among plan operators for all the total orders of a partially-ordered plan. The explanations are based on the Modal Truth Criterion which states the necessary and sufficient conditions for ensuring the truth of a proposition at any point in a plan, for a class of partially ordered plans. The generalizations obtained by this method guarantee successful and interaction-free execution of any total order of the generalized plan. In addition, the systematic derivation of the generalization algorithms from the Modal Truth Criterion obviates the need for carrying out a separate formal proof of correctness of the EBG algorithms.
Spatial complexity of solutions of higher order partial differential equations
NASA Astrophysics Data System (ADS)
Kukavica, Igor
2004-03-01
We address spatial oscillation properties of solutions of higher order parabolic partial differential equations. In the case of the Kuramoto-Sivashinsky equation ut + uxxxx + uxx + u ux = 0, we prove that for solutions u on the global attractor, the quantity card {x epsi [0, L]:u(x, t) = lgr}, where L > 0 is the spatial period, can be bounded by a polynomial function of L for all \\lambda\\in{\\Bbb R} . A similar property is proven for a general higher order partial differential equation u_t+(-1)^{s}\\partial_x^{2s}u+ \\sum_{k=0}^{2s-1}v_k(x,t)\\partial_x^k u =0 .
NASA Astrophysics Data System (ADS)
Ishida, Takeshi; Mori, Shunsuke; Douwaki, Kiyoshi
It is said that the cogeneration system (CGS) is an effective countermeasure for energy saving and CO2 reduction in the commercial building. However, the economic, energy and environmental efficiency of CGS varies so much depending on the annual load factor and the demand patterns of heat and electric power. In this research, we develop a model to evaluate the optimum decision on the capacity and the operating pattern of CGS by nonlinear mixing integer programming in order to formulate the partial load properties of CGS in practical operation, since the existing optimization models without partial load properties could have generated too optimistic evaluation of CGS. The compatibility between the economy and the energy saving of the CGS implementation planning has been the problem. Our system proposes a new measure to develop an optimal energy saving system under the constraint of economic efficiency as the investment recovery years of CGS for the commercial building. Our system has been applied to the case of hotel building. The results show us that the optimum CGS capacity planning generated by our model provides more effective solution compared to the existing simulation tools used generally without optimization capability.
Partial integer decorrelation: optimum trade-off between variance reduction and bias amplification
NASA Astrophysics Data System (ADS)
Henkel, Patrick; Günther, Christoph
2010-01-01
Different techniques have been developed for determining carrier phase ambiguities, ranging from float approximations to the efficient solution of the integer least square problem by the LAMBDA method. The focus so far was on double-differenced measurements. Practical implementations of the LAMBDA method lead to a residual probability of wrong fixing of the order one percent. For safety critical applications, this probability had to be reduced by eight orders of magnitude, which could be achieved by linear multi-frequency code-carrier combinations. Scenarios with single or no differences include biases due to orbit errors, satellite clock offsets, as well as residual code and phase biases. For this case, a linear combination of Galileo E1 and E5 code and carrier phase measurements with a wavelength of 3.285 m and a noise level of a few centimeters is derived. This ionosphere-free combination preserves the orbit and clock errors, and suppresses the E1 code multipath by 12.6 dB. Since integer decorrelation transformations, as used in the LAMBDA method, inflate biases, the number of such transformations must be limited, and applied in a judicious order. With a Galileo type constellation, this leads to a vertical standard deviation of ca. 20 cm, while keeping the probability of wrong fixing extremely low for code biases of 10 cm, and phase biases of 0.1 cycle, combined in a worst case.
Latent Partially Ordered Classification Models and Normal Mixtures
ERIC Educational Resources Information Center
Tatsuoka, Curtis; Varadi, Ferenc; Jaeger, Judith
2013-01-01
Latent partially ordered sets (posets) can be employed in modeling cognitive functioning, such as in the analysis of neuropsychological (NP) and educational test data. Posets are cognitively diagnostic in the sense that classification states in these models are associated with detailed profiles of cognitive functioning. These profiles allow for…
Generalized Second-Order Partial Derivatives of 1/r
ERIC Educational Resources Information Center
Hnizdo, V.
2011-01-01
The generalized second-order partial derivatives of 1/r, where r is the radial distance in three dimensions (3D), are obtained using a result of the potential theory of classical analysis. Some non-spherical-regularization alternatives to the standard spherical-regularization expression for the derivatives are derived. The utility of a…
NASA Technical Reports Server (NTRS)
Graves, R. A., Jr.
1975-01-01
The previously obtained second-order-accurate partial implicitization numerical technique used in the solution of fluid dynamic problems was modified with little complication to achieve fourth-order accuracy. The Von Neumann stability analysis demonstrated the unconditional linear stability of the technique. The order of the truncation error was deduced from the Taylor series expansions of the linearized difference equations and was verified by numerical solutions to Burger's equation. For comparison, results were also obtained for Burger's equation using a second-order-accurate partial-implicitization scheme, as well as the fourth-order scheme of Kreiss.
Multimedia document retrieval system using partially ordered/partially reliable transport service
NASA Astrophysics Data System (ADS)
Conrad, Phillip T.; Golden, Edward; Amer, Paul D.; Marasli, Rahmi
1996-03-01
We investigate the benefits of using a partially-ordered/partially-reliable (PO/PR) transport service for multimedia document retrieval over the Internet by implementing a prototype system. We introduce PMSL, a document specification language combining aspects of Little and Ghafoor's OCPN with features for graceful degradation. We then show that for retrieval of PMSL documents, our PO/PR transport protocol (POCv2) provides several benefits over traditional protocols such as TCP or UDP. First, POCv2 provides mechanisms to achieve the reliability and order requirements of individual multimedia objects as specified by a document author. Second, when network conditions are poor (e.g., high loss rates), POCv2 provides for graceful degradation. Finally, POCv2 simplifies application development by providing appropriate mechanisms for synchronization.
N site ordering effect on partially ordered Fe{sub 16}N{sub 2}
Ji Nian; Wang Jianping
2011-02-28
Partially ordered Fe{sub 16}N{sub 2} thin films have been fabricated on Fe (001)-buffered GaAs (001) single-crystal substrates by a facing target sputtering process. The saturation magnetization has been systematically investigated as a function of N site ordering in partially ordered Fe{sub 16}N{sub 2} thin films, which is found to be increased monotonically with the increase in the N site ordering parameter, reaching up to 2.68 T at high ordering case. A model discussion is provided based on the partial localization of 3d electron states in this material system, which successfully rationalizes the formation of the giant saturation magnetization in chemically ordered Fe{sub 16}N{sub 2}. We further demonstrate that the average magnetic moment of partially ordered Fe{sub 16}N{sub 2} sensitively depends on the special arrangement of Fe{sub 6}N clusters, which is the key to realize high magnetic moment in this material system.
Zapata, Francisco; Kreinovich, Vladik; Joslyn, Cliff A.; Hogan, Emilie A.
2013-08-01
To make a decision, we need to compare the values of quantities. In many practical situations, we know the values with interval uncertainty. In such situations, we need to compare intervals. Allen’s algebra describes all possible relations between intervals on the real line, and ordering relations between such intervals are well studied. In this paper, we extend this description to intervals in an arbitrary partially ordered set (poset). In particular, we explicitly describe ordering relations between intervals that generalize relation between points. As auxiliary results, we provide a logical interpretation of the relation between intervals, and extend the results about interval graphs to intervals over posets.
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2012-08-02
... Bureau of Land Management Public Land Order No. 7793; Partial Revocation of Public Land Order No. 1535; South Dakota AGENCY: Bureau of Land Management, Interior. ACTION: Public land order. SUMMARY: This order partially revokes the withdrawal created by Public Land Order No. 1535 insofar as it affects 14.43 acres...
Graphene: A partially ordered non-periodic solid
NASA Astrophysics Data System (ADS)
Wei, Dongshan; Wang, Feng
2014-10-01
Molecular dynamics simulations were performed to study the structural features of graphene over a wide range of temperatures from 50 to 4000 K using the PPBE-G potential [D. Wei, Y. Song, and F. Wang, J. Chem. Phys. 134, 184704 (2011)]. This potential was developed by force matching the Perdew-Burke-Ernzerhof (PBE) exchange correlation functional and has been validated previously to provide accurate potential energy surface for graphene at temperatures as high as 3000 K. Simulations with the PPBE-G potential are the best available approximation to a direct Car-Parrinello Molecular Dynamics study of graphene. One advantage of the PBE-G potential is to allow large simulation boxes to be modeled efficiently so that properties showing strong finite size effects can be studied. Our simulation box contains more than 600 000 C atoms and is one of the largest graphene boxes ever modeled. With the PPBE-G potential, the thermal-expansion coefficient is negative up to 4000 K. With a large box and an accurate potential, the critical exponent for the scaling properties associated with the normal-normal and height-height correlation functions was confirmed to be 0.85. This exponent remains constant up to 4000 K suggesting graphene to be in the deeply cooled regime even close to the experimental melting temperature. The reduced peak heights in the radial distribution function of graphene show an inverse power law dependence to distance, which indicates that a macroscopic graphene sheet will lose long-range crystalline order as predicted by the Mermin-Wagner instability. Although graphene loses long-range translational order, it retains long range orientational order as indicated by its orientational correlation function; graphene is thus partially ordered but not periodic.
Graphene: a partially ordered non-periodic solid.
Wei, Dongshan; Wang, Feng
2014-10-14
Molecular dynamics simulations were performed to study the structural features of graphene over a wide range of temperatures from 50 to 4000 K using the PPBE-G potential [D. Wei, Y. Song, and F. Wang, J. Chem. Phys. 134, 184704 (2011)]. This potential was developed by force matching the Perdew-Burke-Ernzerhof (PBE) exchange correlation functional and has been validated previously to provide accurate potential energy surface for graphene at temperatures as high as 3000 K. Simulations with the PPBE‑G potential are the best available approximation to a direct Car-Parrinello Molecular Dynamics study of graphene. One advantage of the PBE-G potential is to allow large simulation boxes to be modeled efficiently so that properties showing strong finite size effects can be studied. Our simulation box contains more than 600,000 C atoms and is one of the largest graphene boxes ever modeled. With the PPBE-G potential, the thermal-expansion coefficient is negative up to 4000 K. With a large box and an accurate potential, the critical exponent for the scaling properties associated with the normal-normal and height-height correlation functions was confirmed to be 0.85. This exponent remains constant up to 4000 K suggesting graphene to be in the deeply cooled regime even close to the experimental melting temperature. The reduced peak heights in the radial distribution function of graphene show an inverse power law dependence to distance, which indicates that a macroscopic graphene sheet will lose long-range crystalline order as predicted by the Mermin-Wagner instability. Although graphene loses long-range translational order, it retains long range orientational order as indicated by its orientational correlation function; graphene is thus partially ordered but not periodic. PMID:25318732
Graphene: A partially ordered non-periodic solid
Wei, Dongshan; Wang, Feng
2014-10-14
Molecular dynamics simulations were performed to study the structural features of graphene over a wide range of temperatures from 50 to 4000 K using the PPBE-G potential [D. Wei, Y. Song, and F. Wang, J. Chem. Phys. 134, 184704 (2011)]. This potential was developed by force matching the Perdew-Burke-Ernzerhof (PBE) exchange correlation functional and has been validated previously to provide accurate potential energy surface for graphene at temperatures as high as 3000 K. Simulations with the PPBE‑G potential are the best available approximation to a direct Car-Parrinello Molecular Dynamics study of graphene. One advantage of the PBE-G potential is to allow large simulation boxes to be modeled efficiently so that properties showing strong finite size effects can be studied. Our simulation box contains more than 600 000 C atoms and is one of the largest graphene boxes ever modeled. With the PPBE-G potential, the thermal-expansion coefficient is negative up to 4000 K. With a large box and an accurate potential, the critical exponent for the scaling properties associated with the normal-normal and height-height correlation functions was confirmed to be 0.85. This exponent remains constant up to 4000 K suggesting graphene to be in the deeply cooled regime even close to the experimental melting temperature. The reduced peak heights in the radial distribution function of graphene show an inverse power law dependence to distance, which indicates that a macroscopic graphene sheet will lose long-range crystalline order as predicted by the Mermin-Wagner instability. Although graphene loses long-range translational order, it retains long range orientational order as indicated by its orientational correlation function; graphene is thus partially ordered but not periodic.
Approximated optimum condition of second order response surface model with correlated observations
NASA Astrophysics Data System (ADS)
Somayasa, Wayan
2016-06-01
In the present paper we establish an inference procedure for the eigenvalues of the model matrix of the second-order response surface model (RSM). In contrast to the classical treatment where the sample are assumed to be independently distributed, in this work we do not need such distributional simplification. The confidence region for the unknown vector of the eigenvalues is derived by means of delta method. The finite sample behavior of the convergence result is discussed by Monte Carlo Simulation. We get the approximated distribution of the pivotal quantity of the population eigenvalues as a chi-square distribution model. Next we attempt to apply the method to a real data provided by a mining industry. The data represents the percentage of cobalt (Co) observed over the exploration region.
NASA Technical Reports Server (NTRS)
Kasami, Tadao; Takata, Toyoo; Fujiwara, Toru; Lin, Shu
1993-01-01
It was shown earlier that for a punctured Reed-Muller (RM) code or a primitive BCH code, which contains a punctured RM code of the same minimum distance as a large subcode, the state complexity of the minimal trellis diagram is much greater than that for an equivalent code obtained by a proper permutation on the bit positions. To find a permutation on the bit positions for a given code that minimizes the state complexity of its minimal trellis diagram is an interesting and challenging problem. This permutation problem is related to the generalized Hamming weight hierarchy of a code, and is shown that for RM codes, the standard binary order of bit positions is optimum at every bit position with respect to the state complexity of a minimal trellis diagram by using a theorem due to Wei. The state complexity of trellis diagram for the extended and permuted (64, 24) BCH code is discussed.
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Optimal allocation under partial ordering of lifetimes of components
NASA Astrophysics Data System (ADS)
El-Neweihi, Emad; Sethuraman, Jayaram
1992-08-01
Assembly of systems to maximize reliability when certain components of the systems can be bolstered in different ways is an important theme in reliability theory. This is done under assumptions of various stochastic orderings among the lifetimes of the components and the spares used to bolster them. The powerful techniques of Schur and AI functions are used in this paper to pinpoint optimal allocation results in different settings involving active and standby redundancy allocation, minimal repair and shock, threshold models.
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Phase I Design for Completely or Partially Ordered Treatment Schedules
Wages, Nolan A.; O’Quigley, John; Conaway, Mark R.
2013-01-01
The majority of methods for the design of Phase I trials in oncology are based upon a single course of therapy, yet in actual practice it may be the case that there is more than one treatment schedule for any given dose. Therefore, the probability of observing a dose-limiting toxicity (DLT) may depend upon both the total amount of the dose given, as well as the frequency with which it is administered. The objective of the study then becomes to find an acceptable combination of both dose and schedule. Past literature on designing these trials has entailed the assumption that toxicity increases monotonically with both dose and schedule. In this article, we relax this assumption for schedules and present a dose-schedule finding design that can be generalized to situations in which we know the ordering between all schedules and those in which we do not. We present simulation results that compare our method to other suggested dose-schedule finding methodology. PMID:24114957
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Easy axis alignment of chemically partially ordered FePt nanoparticles
Kang, Shishou; Jia Zhiyong; Shi, Shifan; Nikles, David E.; Harrell, J.W.
2005-02-07
Partially ordered Fe{sub 53}Pt{sub 47} nanoparticles with size around 8 nm were prepared by the simultaneous decomposition of iron pentacarbonyl and platinum acetylacetonate. The high boiling point chemical, hexadecylamine, was used as a solvent, and 1-adamantanecarboxylic acid was used as a stabilizer. X-ray diffraction measurements reveal that as-made FePt particles were partially transformed into the ordered L1{sub 0} phase with some weak superlattice peaks. The room-temperature hysteresis loop and remanence curve suggest a broad distribution of anisotropies in the partially ordered particles. By coating the partially ordered FePt nanoparticles with a polyvinylchloride polymer binder, the particles could be re-dispersed in cyclohexanone. Furthermore, the easy axis of the particles coated with the polyvinylchloride polymer binder could be aligned under an external field. Easy axis alignment was confirmed from both alternating gradient magnetometer and x-ray diffraction measurements.
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A Partial Order Reduction Technique for Parallel Timed Automaton Model Checking
NASA Astrophysics Data System (ADS)
Jianhua, Zhao; Linzhang, Wang; Xuandong, Li
We propose a partial order reduction technique for timed automaton model checking in this paper. We first show that the symbolic successors w.r.t. partial order paths can be computed using DBMs. An algorithm is presented to compute such successors incrementally. This algorithm can avoid splitting the symbolic states because of the enumeration order of independent transitions. A reachability analysis algorithm based on this successor computation algorithm is presented. Our technique can be combined with some static analysis techniques in the literate. Further more, we present a rule to avoid exploring all enabled transitions, thus the space requirements of model checking are further reduced.
78 FR 52561 - Public Land Order No. 7820; Partial Modification, Public Water Reserve No. 107; Utah
Federal Register 2010, 2011, 2012, 2013, 2014
2013-08-23
... Bureau of Land Management Public Land Order No. 7820; Partial Modification, Public Water Reserve No. 107... waterholes and designated as Public Water Reserve No. 107. This order opens the lands only to exchange under... Management Act of 1976 (43 U.S.C. 1716) and applicable law, Public Law 111-53 (123 Stat. 1982) directs...
Federal Register 2010, 2011, 2012, 2013, 2014
2010-09-28
... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE INTERIOR Bureau of Land Management Public Land Order No. 7752; Partial Revocation of a Light Station Reservation...: The reservation of public land for the Lime Kiln Light Station created by an Executive Order...
An Isotonic Partial Credit Model for Ordering Subjects on the Basis of Their Sum Scores
ERIC Educational Resources Information Center
Ligtvoet, Rudy
2012-01-01
In practice, the sum of the item scores is often used as a basis for comparing subjects. For items that have more than two ordered score categories, only the partial credit model (PCM) and special cases of this model imply that the subjects are stochastically ordered on the common latent variable. However, the PCM is very restrictive with respect…
Federal Register 2010, 2011, 2012, 2013, 2014
2012-06-05
... Bureau of Land Management Public Land Order No. 7789; Partial Withdrawal Revocation and Transfer of Administrative Jurisdiction for Fort Vancouver National Historic Site, WA AGENCY: Bureau of Land Management... it was withdrawn. This order also transfers administrative jurisdiction of the land to the...
75 FR 44281 - Public Land Order No. 7747; Partial Revocation, Juniper Butte Range; Idaho
Federal Register 2010, 2011, 2012, 2013, 2014
2010-07-28
... Bureau of Land Management Public Land Order No. 7747; Partial Revocation, Juniper Butte Range; Idaho... United States Air Force in Owyhee County, Idaho for the Juniper Butte Range. This order also opens the... Force as part of the Juniper Butte Range under Public Law 105-261. The parcel of land described in...
Multi-input partial eigenvalue assignment for high order control systems with time delay
NASA Astrophysics Data System (ADS)
Zhang, Lei
2016-05-01
In this paper, we consider the partial eigenvalue assignment problem for high order control systems with time delay. Ram et al. (2011) [1] have shown that a hybrid method can be used to solve partial quadratic eigenvalue assignment problem of single-input vibratory system. Based on this theory, a rather simple algorithm for solving multi-input partial eigenvalue assignment for high order control systems with time delay is proposed. Our method can assign the expected eigenvalues and keep the no spillover property. The solution can be implemented with only partial information of the eigenvalues and the corresponding eigenvectors of the matrix polynomial. Numerical examples are given to illustrate the efficiency of our approach.
A note on the nonlocal boundary value problem for a third order partial differential equation
NASA Astrophysics Data System (ADS)
Belakroum, Kheireddine; Ashyralyev, Allaberen; Guezane-Lakoud, Assia
2016-08-01
The nonlocal boundary-value problem for a third order partial differential equation d/3u (t ) d t3 +A d/u (t ) d t =f (t ), 0
Multi-strategy learning of search control for partial-order planning
Estlin, T.A.; Mooney, R.J.
1996-12-31
Most research in planning and learning has involved linear, state-based planners. This paper presents SCOPE, a system for learning search-control rules that improve the performance of a partial-order planner. SCOPE integrates explanation-based and inductive learning techniques to acquire control rules for a partial-order planner. Learned rules are in the form of selection heuristics that help the planner choose between competing plan refinements. Specifically, SCOPE learns domain-specific control rules for a version of the UCPOP planning algorithm. The resulting system is shown to produce significant speedup in two different planning domains.
NASA Astrophysics Data System (ADS)
Ortiz, J. V.
1988-11-01
Vertical ionization energies of Li-3, Na-3, LiNa-2, and Li2Na- are calculated with ab initio electron propagator theory. D∞h and C∞v isomers for the heteronuclear triatomics are considered. Two doublet final states with Σ symmetry are considered for each case. Koopmans's theorem, second order, third order, and partial fourth order results form a steadily converging series. Outer valence approximation results are not similar and are probably inferior to the partial fourth order results. Convergence of results with respect to the order of electron interaction in the propagator self-energy and with respect to basis set saturation is achieved to within 0.1 eV.
77 FR 58867 - Public Land Order No. 7977; Partial Revocation, Power Site Reserve No. 78; Colorado
Federal Register 2010, 2011, 2012, 2013, 2014
2012-09-24
... Forest System land withdrawn for protection of water power values designated as Power Site Reserve No. 78... Bureau of Land Management Public Land Order No. 7977; Partial Revocation, Power Site Reserve No. 78... July 2, 1910, which established Power Site Reserve No. 78, is no longer needed for the purpose...
NASA Astrophysics Data System (ADS)
Al-Islam, Najja Shakir
In this Dissertation, the existence of pseudo almost periodic solutions to some systems of nonlinear hyperbolic second-order partial differential equations is established. For that, (Al-Islam [4]) is first studied and then obtained under some suitable assumptions. That is, the existence of pseudo almost periodic solutions to a hyperbolic second-order partial differential equation with delay. The second-order partial differential equation (1) represents a mathematical model for the dynamics of gas absorption, given by uxt+a x,tux=Cx,t,u x,t , u0,t=4 t, 1 where a : [0, L] x RR , C : [0, L] x R x RR , and ϕ : RR are (jointly) continuous functions ( t being the greatest integer function) and L > 0. The results in this Dissertation generalize those of Poorkarimi and Wiener [22]. Secondly, a generalization of the above-mentioned system consisting of the non-linear hyperbolic second-order partial differential equation uxt+a x,tux+bx,t ut+cx,tu=f x,t,u, x∈ 0,L,t∈ R, 2 equipped with the boundary conditions ux,0 =40x, u0,t=u 0t, uxx,0=y 0x, x∈0,L, t∈R, 3 where a, b, c : [0, L ] x RR and f : [0, L] x R x RR are (jointly) continuous functions is studied. Under some suitable assumptions, the existence and uniqueness of pseudo almost periodic solutions to particular cases, as well as the general case of the second-order hyperbolic partial differential equation (2) are studied. The results of all studies contained within this text extend those obtained by Aziz and Meyers [6] in the periodic setting.
Scalable Replay with Partial-Order Dependencies for Message-Logging Fault Tolerance
Lifflander, Jonathan; Meneses, Esteban; Menon, Harshita; Miller, Phil; Krishnamoorthy, Sriram; Kale, Laxmikant
2014-09-22
Deterministic replay of a parallel application is commonly used for discovering bugs or to recover from a hard fault with message-logging fault tolerance. For message passing programs, a major source of overhead during forward execution is recording the order in which messages are sent and received. During replay, this ordering must be used to deterministically reproduce the execution. Previous work in replay algorithms often makes minimal assumptions about the programming model and application in order to maintain generality. However, in many cases, only a partial order must be recorded due to determinism intrinsic in the code, ordering constraints imposed by the execution model, and events that are commutative (their relative execution order during replay does not need to be reproduced exactly). In this paper, we present a novel algebraic framework for reasoning about the minimum dependencies required to represent the partial order for different concurrent orderings and interleavings. By exploiting this theory, we improve on an existing scalable message-logging fault tolerance scheme. The improved scheme scales to 131,072 cores on an IBM BlueGene/P with up to 2x lower overhead than one that records a total order.
Das, Saptarshi; Pan, Indranil; Das, Shantanu
2015-09-01
An optimal trade-off design for fractional order (FO)-PID controller is proposed with a Linear Quadratic Regulator (LQR) based technique using two conflicting time domain objectives. A class of delayed FO systems with single non-integer order element, exhibiting both sluggish and oscillatory open loop responses, have been controlled here. The FO time delay processes are handled within a multi-objective optimization (MOO) formalism of LQR based FOPID design. A comparison is made between two contemporary approaches of stabilizing time-delay systems withinLQR. The MOO control design methodology yields the Pareto optimal trade-off solutions between the tracking performance and total variation (TV) of the control signal. Tuning rules are formed for the optimal LQR-FOPID controller parameters, using median of the non-dominated Pareto solutions to handle delayed FO processes. PMID:26096954
Bounding the Resource Availability of Partially Ordered Events with Constant Resource Impact
NASA Technical Reports Server (NTRS)
Frank, Jeremy
2004-01-01
We compare existing techniques to bound the resource availability of partially ordered events. We first show that, contrary to intuition, two existing techniques, one due to Laborie and one due to Muscettola, are not strictly comparable in terms of the size of the search trees generated under chronological search with a fixed heuristic. We describe a generalization of these techniques called the Flow Balance Constraint to tightly bound the amount of available resource for a set of partially ordered events with piecewise constant resource impact We prove that the new technique generates smaller proof trees under chronological search with a fixed heuristic, at little increase in computational expense. We then show how to construct tighter resource bounds but at increased computational cost.
Schäfer, H; Mädler, B; Sternin, E
1998-01-01
The partial orientation of multilamellar vesicles (MLVs) in high magnetic fields is known to affect the shape of 2H NMR spectra. There are numerical methods for extracting either the orientational order parameters of lipid molecules for a random distribution of domain orientations in the sample, or the distribution of orientations for a known set of spectral anisotropies. A first attempt at determining the orientational order parameters in the presence of an unknown nonrandom distribution of orientations is presented. The numerical method is based on the Tikhonov regularization algorithm. It is tested using simulated partially oriented spectra. An experimental spectrum of a phospholipid-ether mixture in water is analyzed as an example. The experimental spectrum is consistent with an ellipsoidal shape of MLVs with a ratio of semiaxes of approximately 3.4. PMID:9533713
Higher-order numerical solutions using cubic splines. [for partial differential equations
NASA Technical Reports Server (NTRS)
Rubin, S. G.; Khosla, P. K.
1975-01-01
A cubic spline collocation procedure has recently been developed for the numerical solution of partial differential equations. In the present paper, this spline procedure is reformulated so that the accuracy of the second-derivative approximation is improved and parallels that previously obtained for lower derivative terms. The final result is a numerical procedure having overall third-order accuracy for a non-uniform mesh and overall fourth-order accuracy for a uniform mesh. Solutions using both spline procedures, as well as three-point finite difference methods, will be presented for several model problems.-
On well-partial-order theory and its application to combinatorial problems of VLSI design
NASA Technical Reports Server (NTRS)
Fellows, M.; Langston, M.
1990-01-01
We nonconstructively prove the existence of decision algorithms with low-degree polynomial running times for a number of well-studied graph layout, placement, and routing problems. Some were not previously known to be in p at all; others were only known to be in p by way of brute force or dynamic programming formulations with unboundedly high-degree polynomial running times. Our methods include the application of the recent Robertson-Seymour theorems on the well-partial-ordering of graphs under both the minor and immersion orders. We also briefly address the complexity of search versions of these problems.
Fourth-order partial differential equation noise removal on welding images
Halim, Suhaila Abd; Ibrahim, Arsmah; Sulong, Tuan Nurul Norazura Tuan; Manurung, Yupiter HP
2015-10-22
Partial differential equation (PDE) has become one of the important topics in mathematics and is widely used in various fields. It can be used for image denoising in the image analysis field. In this paper, a fourth-order PDE is discussed and implemented as a denoising method on digital images. The fourth-order PDE is solved computationally using finite difference approach and then implemented on a set of digital radiographic images with welding defects. The performance of the discretized model is evaluated using Peak Signal to Noise Ratio (PSNR). Simulation is carried out on the discretized model on different level of Gaussian noise in order to get the maximum PSNR value. The convergence criteria chosen to determine the number of iterations required is measured based on the highest PSNR value. Results obtained show that the fourth-order PDE model produced promising results as an image denoising tool compared with median filter.
Characterization of partially ordered GaInP/GaAs heterointerfaces by the quantum Hall effect
NASA Astrophysics Data System (ADS)
Uchida, Kazuo; Satoh, Kiwamu; Asano, Keita; Koizumi, Atsushi; Nozaki, Shinji
2013-05-01
The new approach to the characterization of semiconductor interfacial properties by the quantum Hall effect (QHE) and the scanning near field optical microscopy (SNOM) is demonstrated to the heterointerfaces of partially ordered GaInP/GaAs grown by low-pressure Metal Organic Vapor Phase Epitaxy. The Shubnikov de-Haas (SdH) oscillations and the Hall plateaus are observed in the heterointerfaces of both the less-ordered and more-ordered GaInP/GaAs samples with a large clover-shape, but these samples exhibit both 2D and 3D electron behaviors. In contrast to large clover-shaped samples, the distinct SdH oscillations and the Hall plateaus in the less-ordered sample, while the single SdH oscillation and the corresponding large plateau in the more-ordered small Hall-bar sample are observed. These results suggest that there may be many domains, each having a different carrier density and sizes in the less-ordered sample, while one or few large domains with uniform carrier concentration and sizes in the more-ordered sample. In SNOM measurements, PL intensity varies in the mapping of the more-ordered sample and it is concluded that the variation of the PL intensity may result from an inhomogeneous distribution of non-radiative recombination centers in the more-ordered sample.
Analysis of Multiple Partially Ordered Responses to Belief Items with Don't Know Option.
Ip, Edward H; Chen, Shyh-Huei; Quandt, Sara A
2016-06-01
Understanding beliefs, values, and preferences of patients is a tenet of contemporary health sciences. This application was motivated by the analysis of multiple partially ordered set (poset) responses from an inventory on layman beliefs about diabetes. The partially ordered set arises because of two features in the data-first, the response options contain a Don't Know (DK) option, and second, there were two consecutive occasions of measurement. As predicted by the common sense model of illness, beliefs about diabetes were not necessarily stable across the two measurement occasions. Instead of analyzing the two occasions separately, we studied the joint responses across the occasions as a poset response. Few analytic methods exist for data structures other than ordered or nominal categories. Poset responses are routinely collapsed and then analyzed as either rank ordered or nominal data, leading to the loss of nuanced information that might be present within poset categories. In this paper we developed a general class of item response models for analyzing the poset data collected from the Common Sense Model of Diabetes Inventory. The inferential object of interest is the latent trait that indicates congruence of belief with the biomedical model. To apply an item response model to the poset diabetes inventory, we proved that a simple coding algorithm circumvents the requirement of writing new codes such that standard IRT software could be directly used for the purpose of item estimation and individual scoring. Simulation experiments were used to examine parameter recovery for the proposed poset model. PMID:25479822
Federal Register 2010, 2011, 2012, 2013, 2014
2012-09-24
... determined that a portion of the land classified under Power Site Classification No. 126 for water power... Bureau of Land Management Public Land Order No. 7798; Partial Modification of Power Site Classification...: This order partially modifies a withdrawal which established Power Site Classification No. 126,...
Guo, Beibei; Li, Yisheng
2015-02-28
Molecularly targeted agent (MTA) combination therapy is in the early stages of development. When using a fixed dose of one agent in combinations of MTAs, toxicity and efficacy do not necessarily increase with an increasing dose of the other agent. Thus, in dose-finding trials for combinations of MTAs, interest may lie in identifying the optimal biological dose combinations (OBDCs), defined as the lowest dose combinations (in a certain sense) that are safe and have the highest efficacy level meeting a prespecified target. The limited existing designs for these trials use parametric dose-efficacy and dose-toxicity models. Motivated by a phase I/II clinical trial of a combination of two MTAs in patients with pancreatic, endometrial, or colorectal cancer, we propose Bayesian dose-finding designs to identify the OBDCs without parametric model assumptions. The proposed approach is based only on partial stochastic ordering assumptions for the effects of the combined MTAs and uses isotonic regression to estimate partially stochastically ordered marginal posterior distributions of the efficacy and toxicity probabilities. We demonstrate that our proposed method appropriately accounts for the partial ordering constraints, including potential plateaus on the dose-response surfaces, and is computationally efficient. We develop a dose-combination-finding algorithm to identify the OBDCs. We use simulations to compare the proposed designs with an alternative design based on Bayesian isotonic regression transformation and a design based on parametric change-point dose-toxicity and dose-efficacy models and demonstrate desirable operating characteristics of the proposed designs. PMID:25413162
NASA Technical Reports Server (NTRS)
Yan, Jue; Shu, Chi-Wang; Bushnell, Dennis M. (Technical Monitor)
2002-01-01
In this paper we review the existing and develop new continuous Galerkin methods for solving time dependent partial differential equations with higher order derivatives in one and multiple space dimensions. We review local discontinuous Galerkin methods for convection diffusion equations involving second derivatives and for KdV type equations involving third derivatives. We then develop new local discontinuous Galerkin methods for the time dependent bi-harmonic type equations involving fourth derivatives, and partial differential equations involving fifth derivatives. For these new methods we present correct interface numerical fluxes and prove L(exp 2) stability for general nonlinear problems. Preliminary numerical examples are shown to illustrate these methods. Finally, we present new results on a post-processing technique, originally designed for methods with good negative-order error estimates, on the local discontinuous Galerkin methods applied to equations with higher derivatives. Numerical experiments show that this technique works as well for the new higher derivative cases, in effectively doubling the rate of convergence with negligible additional computational cost, for linear as well as some nonlinear problems, with a local uniform mesh.
Modeling individual HRTF tensor using high-order partial least squares
NASA Astrophysics Data System (ADS)
Huang, Qinghua; Li, Lin
2014-12-01
A tensor is used to describe head-related transfer functions (HRTFs) depending on frequencies, sound directions, and anthropometric parameters. It keeps the multi-dimensional structure of measured HRTFs. To construct a multi-linear HRTF personalization model, an individual core tensor is extracted from the original HRTFs using high-order singular value decomposition (HOSVD). The individual core tensor in lower-dimensional space acts as the output of the multi-linear model. Some key anthropometric parameters as the inputs of the model are selected by Laplacian scores and correlation analyses between all the measured parameters and the individual core tensor. Then, the multi-linear regression model is constructed by high-order partial least squares (HOPLS), aiming to seek a joint subspace approximation for both the selected parameters and the individual core tensor. The numbers of latent variables and loadings are used to control the complexity of the model and prevent overfitting feasibly. Compared with the partial least squares regression (PLSR) method, objective simulations demonstrate the better performance for predicting individual HRTFs especially for the sound directions ipsilateral to the concerned ear. The subjective listening tests show that the predicted individual HRTFs are approximate to the measured HRTFs for the sound localization.
Karaman, Safa; Toker, Ömer Said; Yüksel, Ferhat; Çam, Mustafa; Kayacier, Ahmed; Dogan, Mahmut
2014-01-01
In the present study, persimmon puree was incorporated into the ice cream mix at different concentrations (8, 16, 24, 32, and 40%) and some physicochemical (dry matter, ash, protein, pH, sugar, fat, mineral, color, and viscosity), textural (hardness, stickiness, and work of penetration), bioactive (antiradical activity and total phenolic content), and sensory properties of samples were investigated. The technique for order preference by similarity to ideal solution approach was used for the determination of optimum persimmon puree concentration based on the sensory and bioactive characteristics of final products. Increase in persimmon puree resulted in a decrease in the dry matter, ash, fat, protein contents, and viscosity of ice cream mix. Glucose, fructose, sucrose, and lactose were determined to be major sugars in the ice cream samples including persimmon and increase in persimmon puree concentration increased the fructose and glucose content. Better melting properties and textural characteristics were observed for the samples with the addition of persimmon. Magnesium, K, and Ca were determined to be major minerals in the samples and only K concentration increased with the increase in persimmon content. Bioactive properties of ice cream samples improved and, in general, acetone-water extracts showed higher bioactivity compared with ones obtained using methanol-water extracts. The technique for order preference by similarity to ideal solution approach showed that the most preferred sample was the ice cream containing 24% persimmon puree. PMID:24268400
Partially ordered mixed hidden Markov model for the disablement process of older adults
Ip, Edward H.; Zhang, Qiang; Rejeski, W. Jack; Harris, Tamara B.; Kritchevsky, Stephen
2013-01-01
At both the individual and societal levels, the health and economic burden of disability in older adults is enormous in developed countries, including the U.S. Recent studies have revealed that the disablement process in older adults often comprises episodic periods of impaired functioning and periods that are relatively free of disability, amid a secular and natural trend of decline in functioning. Rather than an irreversible, progressive event that is analogous to a chronic disease, disability is better conceptualized and mathematically modeled as states that do not necessarily follow a strict linear order of good-to-bad. Statistical tools, including Markov models, which allow bidirectional transition between states, and random effects models, which allow individual-specific rate of secular decline, are pertinent. In this paper, we propose a mixed effects, multivariate, hidden Markov model to handle partially ordered disability states. The model generalizes the continuation ratio model for ordinal data in the generalized linear model literature and provides a formal framework for testing the effects of risk factors and/or an intervention on the transitions between different disability states. Under a generalization of the proportional odds ratio assumption, the proposed model circumvents the problem of a potentially large number of parameters when the number of states and the number of covariates are substantial. We describe a maximum likelihood method for estimating the partially ordered, mixed effects model and show how the model can be applied to a longitudinal data set that consists of N = 2,903 older adults followed for 10 years in the Health Aging and Body Composition Study. We further statistically test the effects of various risk factors upon the probabilities of transition into various severe disability states. The result can be used to inform geriatric and public health science researchers who study the disablement process. PMID:24058222
Fully and partially coherent pathways in multiply enhanced odd-order wave-mixing spectroscopy.
Mathew, Nathan A; Yurs, Lena A; Block, Stephen B; Pakoulev, Andrei V; Kornau, Kathryn M; Sibert, Edwin L; Wright, John C
2010-01-21
Nuclear magnetic resonance spectroscopy relies on using multiple excitation pulses to create multiple quantum coherences that provide great specificity for chemical measurements. Coherent multidimensional spectroscopy (CMDS) is the optical analogue of NMR. Current CMDS methods use three excitation pulses and phase matching to create zero, single, and double quantum coherences. In order to create higher order multiple quantum coherences, the number of interactions must be increased by raising the excitation intensities high enough to create Rabi frequencies that are comparable to the dephasing rates of vibrational coherences. The higher Rabi frequencies create multiple, odd-order coherence pathways. The coherence pathways that involve intermediate populations are partially coherent and are sensitive to population relaxation effects. Pathways that are fully coherent involve only coherences and measure the direct coupling between excited quantum states. The fully coherent pathways are related to the multiple quantum coherences created in multiple pulse NMR methods such as heteronuclear multiple quantum coherence (HMQC) spectroscopy with the important difference that HMQC NMR methods have a defined number of interactions and avoid dynamic Stark effects whereas the multiply enhanced odd-order wave-mixing pathways do not. The difference arises because CMDS methods use phase matching to define the interactions and at high intensities, multiple pathways obey the same phase matching conditions. The multiple pathways correspond to the pathways created by dynamic Stark effects. This paper uses rhodium dicarbonyl chelate (RDC) as a model to demonstrate the characteristics of multiply enhanced odd-order wave-mixing (MEOW) methods. Dynamic Stark effects excite vibrational ladders on the symmetric and asymmetric CO stretch modes and create a series of multiple quantum coherences and populations using partially and fully coherent pathways. Vibrational quantum states up to v = 6
Lermyte, Frederik; Sobott, Frank
2015-08-01
Top-down sequencing approaches are becoming ever more popular for protein characterization, due to the ability to distinguish and characterize different protein isoforms. Under non-denaturing conditions, electron transfer dissociation (ETD) can furthermore provide important information on the exposed surface of proteins or complexes, thereby contributing to the characterization of their higher-order structure. Here, we investigate this approach using top-down ETD of tetrameric hemoglobin, concanavalin A, and alcohol dehydrogenase combined with ion mobility (IM) on a commercially available quadrupole/ion mobility/time-of-flight instrument (Waters Synapt G2). By applying supplemental activation in the transfer cell (post-IM), we release ETD fragments and attain good sequence coverage in the exposed terminal regions of the protein. We investigate the correlation between observed sites of fragmentation with regions of solvent accessibility, as derived from the crystal structure. Ion acceleration prior to ETD is also used to cause collision-induced unfolding (CIU) of the complexes without monomer ejection, as evidenced by the IM profiles. These partially unfolded tetramers show efficient fragmentation in some regions which are not sequenced under more gentle MS conditions. We show that by increasing CIU in small increments and monitoring the changes in the fragmentation pattern, it is possible to follow the initial steps of gas-phase protein unfolding. Fragments from partially unfolded protein complexes are released immediately after electron transfer, prior to IM (they do not share the drift time of their precursor), and observed without the need for supplemental activation. This is further evidence that the higher-order structure in these protein regions has been disrupted. PMID:26081219
Federal Register 2010, 2011, 2012, 2013, 2014
2011-09-27
... conditions of Public Land Order No. 5184 (37 FR 5588 (1972)), as amended, and any other withdrawals... Land Order No. 5184 (37 FR 5588 (1972)), as amended, and any other withdrawal or segregation of record...: This order revokes a Secretarial Order insofar as it affects approximately 606 acres of public...
Masses from an inhomogeneous partial difference equation with higher-order isospin contributions
Masson, P.J.; Jaenecke, J.
1988-07-01
In the present work, a mass equation obtained as the solution of an inhomogeneous partial difference equation is used to predict masses of unknown neutron-rich and proton-rich nuclei. The inhomogeneous source terms contain shell-dependent symmetry energy expressions (quadratic in isospin), and include, as well, an independently derived shell-model Coulomb energy equation which describes all known Coulomb displacement energies with a standarad deviation of sigma/sub c/ = 41 keV. Perturbations of higher order in isospin, previously recognized as a cause of systematic effects in long-range mass extrapolations, are also incorporated. The most general solutions of the inhomogeneous difference equation have been deduced from a chi/sup 2/-minimization procedure based on the recent atomic mass adjustment of Wapstra, Audi, and Hoekstra. Subjecting the solutions further to the condition of charge symmetry preserves the accuracy of Coulomb energies and allows mass predictions for nuclei with both Ngreater than or equal toZ and Z>N. The solutions correspond to a mass equation with 470 parameters. Using this equation, 4385 mass values have been calculated for nuclei with Agreater than or equal to16 (except N = Z = odd for A<40), with a standard deviation of sigma/sub m/ = 194 keV from the experimental masses. copyright 1988 Academic Press, Inc.
The Interplay between QSAR/QSPR Studies and Partial Order Ranking and Formal Concept Analyses
Carlsen, Lars
2009-01-01
The often observed scarcity of physical-chemical and well as toxicological data hampers the assessment of potentially hazardous chemicals released to the environment. In such cases Quantitative Structure-Activity Relationships/Quantitative Structure-Property Relationships (QSAR/QSPR) constitute an obvious alternative for rapidly, effectively and inexpensively generatng missing experimental values. However, typically further treatment of the data appears necessary, e.g., to elucidate the possible relations between the single compounds as well as implications and associations between the various parameters used for the combined characterization of the compounds under investigation. In the present paper the application of QSAR/QSPR in combination with Partial Order Ranking (POR) methodologies will be reviewed and new aspects using Formal Concept Analysis (FCA) will be introduced. Where POR constitutes an attractive method for, e.g., prioritizing a series of chemical substances based on a simultaneous inclusion of a range of parameters, FCA gives important information on the implications associations between the parameters. The combined approach thus constitutes an attractive method to a preliminary assessment of the impact on environmental and human health by primary pollutants or possibly by a primary pollutant well as a possible suite of transformation subsequent products that may be both persistent in and bioaccumulating and toxic. The present review focus on the environmental – and human health impact by residuals of the rocket fuel 1,1-dimethylhydrazine (heptyl) and its transformation products as an illustrative example. PMID:19468330
Yu, P.Y.; Martinez, G.; Zeman, J.; Uchida, K.
2000-12-31
Photoluminescence upconversion (PLU) is a phenomenon in which a sample emits photons with energy higher than that of the excitation photon. This effect has been observed in many materials including rare earth ions doped in insulating hosts and semiconductor heterostructures without using high power lasers as the excitation source. Recently, this effect has been observed also in partially CuPt-ordered GaInP{sub 2} epilayers grown on GaAs substrates. As a spectroscopic technique photoluminescence upconversion is particularly well suited for studying band alignment at heterojunction interface. The value of band-offset has been determined with meV precision using magneto-photoluminescence. Using the fact that the pressure coefficient of electrons in GaAs is higher than those in GaInP{sub 2} they have been able to manipulate the band-offset at the GaInP/GaAs interface. By converting the band-offset from Type I to Type II they were able to demonstrate that the efficiency of the upconversion process is greatly enhanced by a Type II band-offset.
Willey, D
2000-01-01
The optimum population of the world is the one that is most likely to make the option of a good quality of life available to everyone everywhere, both now and in the future. Establishing a consensus about the size of such a population would be an important step towards achieving it. Estimates of an optimum involve three main steps. First, estimate the maximum (carrying capacity) assuming a specified lifestyle. The main criteria are the maintenance of biodiversity, the availability of freshwater, and the availability of land--for agriculture, forestry and artificial systems but above all for the conversion of energy. (In applying the criteria, there are always two questions to ask: 'What is the maximum amount of consumption that the biosphere can stand?' and 'What is an adequate share of such consumption per person?') Second, convert the maximum (two to three billion) into an optimum by applying a far wider range of criteria, including personal liberty, mobility, recreation and political representation. Third, consider just two criteria (economies of scale and technological innovation) in order to ensure that the optimum (one to two billion) has not fallen below the minimum (half to one billion). The estimates are so low because of the need for a huge increase in median per capita consumption if everyone is to have the option of an adequate material standard of living. Opinion-formers are likely not to take much notice of such estimates, but it is probable that minds will be concentrated by an energy shock some time during the next decade. Achieving an optimum world population will not solve the world's major problems, but it would make them solvable. PMID:10824524
Federal Register 2010, 2011, 2012, 2013, 2014
2012-11-26
.... Land selected by, but not conveyed to, the State will be subject to Public Land Order No. 5186, (37 FR...: This order revokes a Secretarial Order insofar as it affects approximately 1,905 acres of public lands... Administration for Air Navigation Site No. 189, is hereby revoked only insofar as it affects the...
Optimum connection management scheduling
NASA Astrophysics Data System (ADS)
Kadar, Ivan
2000-08-01
Connection Management plays a key role in both distributed 'local' network-centric and 'globally' connected info- centric systems. The role of Connection Management is to provide seamless demand-based sharing of the information products. For optimum distributed information fusion performance, these systems must minimize communications delays and maximize message throughput, and at the same time take into account relative-sensors-targets geometrical constraints and data pedigree. In order to achieve overall distributed 'network' effectiveness, these systems must be adaptive, and be able to distribute data s needed in real- time. A system concept will be described which provides optimum capacity-based information scheduling. A specific example, based on a satellite channel, is used to illustrate simulated performance results and their effects on fusion systems performance.
Fan, G.J.; Quan, M.X.; Hu, Z.Q.
1995-08-01
The authors report phase formation during mechanical alloying of Al rich Ti-Al powder blends. Their experimental results further support the idea that the synthesis of Al rich supersaturated solid solutions in the Al-Ti system occurs in the following two steps. First, the ordered L1{sub 2}-Al{sub 3}Ti intermetallic compound is formed at Al/Ti interfaces. Second, the ordered L1{sup 2}-Al{sub 3}Ti compound was partially disordered by mechanical deformation. Meanwhile, Ti or Al atoms dissolve into the partially disordered phase and a supersaturated solid solution is finally obtained. However, the disordering is not complete and the resulting alloys may exhibit partial L1{sub 2} ordering.
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..., which inadvertently omitted words twice in the order. FOR FURTHER INFORMATION CONTACT: Duane Marti, 916-978-4675. Correction In the Federal Register of September 23, 2009, in FR Doc. E9-22846, (1) on...
NASA Astrophysics Data System (ADS)
Jukić, Damir; Denić-Jukić, Vesna
2015-11-01
Time series of rainfall and karst-spring discharge are influenced by various space-time-variant processes involved in the transfer of water in hydrological cycle. The effects of these processes can be exhibited in auto-correlation and cross-correlation functions. Consequently, ambiguities with respect to the effects encoded in the correlation functions exist. To solve this problem, a new statistical method for investigating relationships between rainfall and karst-spring discharge is proposed. The method is based on the determination and analysis of higher-order partial correlation functions and their spectral representations. The study area is the catchment of the Jadro Spring in Croatia. The analyzed daily time series are the air temperature, relative humidity, spring discharge, and rainfall at seven rain-gauges over a period of 19 years, from 1995 to 2013. The application results show that the effects of spatial and temporal variations of hydrological time series and the space-time-variant behaviours of the karst system can be separated from the correlation functions. Specifically, the effect of evapotranspiration can be separated to obtain the forms of correlation functions that represent the hydrogeological characteristics of the karst system. Using the proposed method, it is also possible to separate the effects of the process of groundwater recharge that occurs in neighbouring parts of a catchment to identify the specific contribution of each part of the catchment to the karst-spring discharge. The main quantitative results obtained for the Jadro Spring show that the quick-flow duration is 14 days, the intermediate-flow duration is 80 days, and the pure base flow starts after 80 days. The base flow consists of an inter-catchment groundwater flow. The system memory of the spring is 80 days. The presented results indicate the far-reaching applicability of the proposed method in the analyses of relationships between rainfall and karst-spring discharge; e
76 FR 54484 - Public Land Order No. 7777; Partial Extension of Public Land Order No. 6874; Oregon
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... (56 FR 42540 (1991)), which withdrew National Forest System lands from location and entry under the... Order No. 6874 (56 FR 42540 (1991)), will expire on August 27, 2011, only insofar as it affects the... genetic resources and the expenditure of Federal funds at the Forest Service's Panelli Seed Orchard,...
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... purposes. This order also transfers administrative jurisdiction of the lands to the National Park Service... U.S.C. 1277(e), the National Park Service requested that the 185.88 acres be transferred to its..., Realty Officer, Bureau of Land Management, 5353 North Yellowstone Road, Cheyenne, Wyoming 82003,...
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... land withdrawn for protection of water power values by Power Site Reserve No. 148. This order opens the land to exchange subject to Section 24 of the Federal Power Act. DATES: Effective Date: April 22, 2010... management. This action will permit the consummation of a pending land exchange and reserve the power...
Fultz, B.; Sturhahn, W.; Toellner, T. S.; Alp, E. E.
1999-11-29
Inelastic nuclear resonant scattering spectra were measured on alloys of Fe{sub 3}Al that were chemically disordered, partially-ordered, and DO{sub 3}-ordered. The phonon partial DOS for {sup 57}Fe atoms were extracted from these data, and the change upon disordering in the partial vibrational entropy of Fe atoms was obtained. By comparison to previous calorimetry measurements, it is shown that the contribution of the Fe atoms to the vibrational entropy is a factor of 10 smaller than that of the Al atoms. With the assistance of Born - von Karman model calculations on the ordered alloy, it is shown that differences in the vibrational entropy originate primarily with changes in the optical modes upon disordering. The phonon DOS of {sup 57}Fe was found to change systematically with chemical short range order in the alloy. It is argued that changes in the vibrational entropy originate primarily with changes in the chemical short-range order in the alloy, as opposed to long-range order.
NASA Astrophysics Data System (ADS)
Molamohamadi, Zohreh; Arshizadeh, Rahman; Ismail, Napsiah
2015-05-01
In the classical inventory model, it was assumed that the retailer must settle the accounts of the purchased items as soon as they are received. In practice, however, the supplier usually offers a full or partial delay period to the retailer to pay for the amount of the purchasing costs. In the partial trade credit contract, which is mostly applied to avoid non-payment risks, the retailer must pay for a portion of the purchased goods at the time of ordering and may delay settling the rest until the end of the predefined agreed upon period, so-called credit period. This paper assumes a two-level partial trade credit where both supplier and retailer offer a partial trade credit to their downstream members. The objective here is to determine the retailer's ordering policy of a deteriorating item by formulating his economic order quantity (EOQ) inventory system with backorder as a cost minimization problem. The sensitivity of the variables on different parameters has been also analyzed by applying numerical examples.
Sakai, Masatoshi; Moritoshi, Norifumi; Kuniyoshi, Shigekazu; Yamauchi, Hiroshi; Kudo, Kazuhiro; Masu, Hyuma
2016-04-01
The effect of an applied gate electric field on the charge-order phase in β-(BEDT-TTF)2PF6 single-crystal field-effect transistor structure was observed at around room temperature by technical improvement with respect to sample preparation and electrical measurements. A relatively slight but systematic increase of the electrical conductance induced by the applied gate electric field and its temperature dependence was observed at around the metal-insulator transition temperature (TMI). The temperature dependence of the modulated electrical conductance demonstrated that TMI was shifted toward the lower side by application of a gate electric field, which corresponds to partial dissolution of the charge-order phase. The thickness of the partially dissolved charge order region was estimated to be several score times larger than the charge accumulation region. PMID:27451615
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... Administrative Jurisdiction, Kirtland Air Force Base; New Mexico AGENCY: Bureau of Land Management, Interior..., 123 Stat. 1449 (2009), it is ordered as follows: ] 1. Public Land Order No. 995 (19 FR 5443 (1954... with Kirtland Air Force Base, is hereby revoked only insofar as it affects the following described...
NASA Technical Reports Server (NTRS)
Wolfshtein, M.; Hirsh, R. S.; Pitts, B. H.
1975-01-01
A new method for the solution of non-linear partial differential equations by an ADI procedure is described. Although the method is second order accurate in time, it does not require either iterations or predictor corrector methods to overcome the nonlinearity of the equations. Thus the computational effort required for the solution of the non-linear problem becomes similar to that required for the linear case. The method is applied to a two-dimensional 'extended Burgers equation'. Linear stability is studied, and some numerical solutions obtained. The improved accuracy obtained by the 2nd order truncation error is clearly manifested.
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Kuang, Dengfeng; Charrière, Renée; Matsapey, Natalia; Flury, Manuel; Faucheu, Jenny; Chavel, Pierre
2015-02-23
Anodizing of aluminum generates a porous alumina layer comprising cylindrical nanopores (300 nm diameter) extending essentially perpendicular to the substrate. The pore distribution over the surface exhibits a short-distance order close to hexagonal arrangement. On the contrary, long-distance order cannot be defined: the arrangement is not periodic. Visual observation of such nanoporous layers shows a reddish specular reflectance consistent with reflectance spectrum measurements. This work is a parametric study aiming at demonstrating that color effects are caused by the presence of disorder illustrated by the deviations from periodicity in terms of nanopore location and nanopore radius. Using the method of Rigorous Coupled Wave Analysis (RCWA), the reflectance spectrum has been simulated. Although our calculations were done using a simple one-dimensional (1D) model, a fair fit with experimental results is found. PMID:25836487
Dynamical calculations for RHEED from a partially-ordered Cu 3Au(111) surface
NASA Astrophysics Data System (ADS)
Ma, Y.; Lordi, S.; Flynn, C. P.; Eades, J. A.
1994-01-01
A multislice formalism of Cowley and Moodie [Acta Cryst. 10 (1957) 609] with a recently developed edge patching method has been applied to the RHEED analyses on the order-disorder transition of the Cu 3Au(111) surfaces. The results give the RI- S relation as RI = 0.4 S2.224 ( RI — ratio of reflection intensities, S — long-range orde By combining the RI- T relation experimentally observable by RHEED with the simulated RI- S relation, the needed S- T relation for the transition can be resolved in a straightforward way. The results confirm what was suggested by the experiments [Mater. Res. Soc. Symp. Proc. 237 (1993) 517]: the intensities of the RHEED superstructure reflections from ordering of the Cu and Au is more than 90% sensitive to the outer monolayer alone, thus making RHEED valuable for studies of surface order. The results of the analyses on the attenuation of elastically scattered electrons inside crystal in RHEED are useful to RHEED-related surface analytical techniques: AES, REEL, EDS and RHEED-TRAXS. The investigation on the errors resulting from potential sampling has shown that choosing proper sampling rates in all three dimensions is important to the multislice simulation of RHEED.
Toroidal order in a partially disordered state on a layered triangular lattice: implication to UNi4B
NASA Astrophysics Data System (ADS)
Hayami, Satoru; Kusunose, Hiroaki; Motome, Yukitoshi
2015-03-01
A partial disorder on a layered triangular lattice is theoretically investigated from a viewpoint of toroidal ordering and magnetoelectric effects. We consider an extended periodic Anderson model including a site-dependent antisymmetric spin-orbit coupling between conduction and localized electrons. We show that, by the mean-field approximation, the model exhibits a coplanar vortex-lattice-type magnetic order as observed in a hexagonal uranium compound UNi4B, in the parameter region with intermediate hybridization and electron correlation. This peculiar state accommodates a toroidal order, which leads to the linear magnetoelectric effect. We discuss the implications of our results to UNi4B, focusing on the possible source of the site-dependent antisymmetric spin-orbit coupling.
NASA Astrophysics Data System (ADS)
Burlutskaya, M. Sh.
2014-01-01
The Fourier method is used to find a classical solution of the mixed problem for a first-order differential equation with involution and periodic boundary conditions. The application of the Fourier method is substantiated using refined asymptotic formulas obtained for the eigenvalues and eigenfunctions of the corresponding spectral problem. The Fourier series representing the formal solution is transformed using certain techniques, and the possibility of its term-by-term differentiation is proved. Minimal requirements are imposed on the initial data of the problem.
Asynchronous consensus of multiple second-order agents with partial state information
NASA Astrophysics Data System (ADS)
Gao, Yanping; Zuo, Min; Jiang, Tongqiang; Du, Junping; Ma, Jingwei
2013-05-01
This article studies the asynchronous consensus problem of multiple second-order agents in a sampled-data setting, where asynchrony means that the sampling period of each agent is independent of the others. It is assumed that each agent can only obtain the information of its positions relative to its neighbours at sampling instants. First, a discrete-time protocol is provided based on velocity estimation, and a sufficient and necessary condition for consensus under this protocol is established in virtue of properties of periodic systems. Second, a continuous-time protocol is presented by the theory of dynamic output feedback control, and a sufficient condition for consensus under this protocol is obtained by applying an input delay approach. Simulations are performed to illustrate the effectiveness of the theoretical results.
NASA Astrophysics Data System (ADS)
Xu, Yonggen; Li, Yude; Dan, Youquan; Du, Quan; Wang, Shijian
2016-07-01
The Wigner distribution function (WDF) has been used to study the propagation properties of partially coherent Laguerre Gaussian (PCLG) beams through atmospheric turbulence. Based on the extended Huygens-Fresnel principle, an analytical formula of the propagation matrixes in terms of the second-order moments of the WDF for PCLG Beams in the receiving plane is derived. And then the analytical formulae for the curvature radii of PCLG Beams propagating in turbulence are given by the second-order moments of the WDF. The numerical results indicate that the curvature radius of PCLG Beams changes more rapidly in turbulence than that in the free space. The influence of the transverse coherence width and the beam waist width on the curvature radius of PCLG Beams is obvious, while the laser wavelength and the inner scale of turbulence have a slight effect. The study results may be useful for remote sensing and free space optical communications.
Granado, E; Lynn, J W; Jardim, R F; Torikachvili, M S
2013-01-01
Neutron diffraction on the double perovskite Sr(2)YRuO(6) with a quasi-fcc lattice of Ru moments reveals planar magnetic correlations that condense into a partial long-range ordered state with coupled alternate antiferromagnetic (AFM) YRuO(4) square layers coexisting with the short-range correlations below T(N1) = 32 K. A second transition to a fully ordered AFM state below T(N2) = 24 K is observed. The reduced dimensionality of the spin correlations is arguably due to a cancellation of the magnetic coupling between consecutive AFM square layers in fcc antiferromagnets, which is the simplest three-dimensional frustrated magnet model system. PMID:23383833
Optimum propeller wind turbines
NASA Astrophysics Data System (ADS)
Sanderson, R. J.; Archer, R. D.
1983-12-01
The Prandtl-Betz-Theodorsen theory of heavily loaded airscrews has been adapted to the design of propeller windmills which are to be optimized for maximum power coefficient. It is shown that the simpler, light-loading, constant-area wake assumption can generate significantly different 'optimum' performance and geometry, and that it is therefore not appropriate to the design of propeller wind turbines when operating in their normal range of high-tip-speed-to-wind-speed ratio. Design curves for optimum power coefficient are presented and an example of the design of a typical two-blade optimum rotor is given.
NASA Astrophysics Data System (ADS)
Thangam, A.
2014-02-01
In today's fast marketing over the Internet or online, many retailers want to trade at the same time and change their marketing strategy to attract more customers. Some of the customers may decide to cancel their orders partially with a retailer due to various reasons such as increase in customer's waiting time, loss of customer's goodwill on retailer's business, and attractive promotional schemes offered by other retailers. Even though there is a lag in trading and order cancellation, this paper attempts to develop the retailer's inventory model with the effect of order cancellations during advance sales period. The retailer announces a price discount program during advance sales period to promote his sales and also offers trade credit financing during the sales periods. The retailer availing trade credit period from his supplier offers a permissible delay period to his customers. The customer who gets an item is allowed to pay on or before the permissible delay period which is accounted from the buying time rather than from the start period of inventory sales. This accounts for significant changes in the calculations of interest payable and interest earned by the retailer. The retailer's total cost is minimized so as to find out the optimal replenishment cycle time and price discount policies through a solution procedure. The results derived in mathematical theorems are implemented in numerical examples, and sensitivity analyses on several inventory parameters are obtained.
NASA Astrophysics Data System (ADS)
Thangam, A.
2015-03-01
In today's fast marketing over the Internet or online, many retailers want to trade at the same time and change their marketing strategy to attract more customers. Some of the customers may decide to cancel their orders partially with a retailer due to various reasons such as increase in customer's waiting time, loss of customer's goodwill on retailer's business, attractive promotional schemes offered by other retailers etc. Even though there is a lag in trading and order cancelation, this paper attempts to develop the retailer's inventory model with the effect of order cancelations during advance sales period. The retailer announces a price discount program during advance sales period to promote his sales and also he offers trade credit financing during the sales periods. The retailer availing trade credit period from his supplier offers a permissible delay period to his customers. The customer who gets an item has allowed paying on or before the permissible delay period which is accounted from the buying time rather than the start period of inventory sales. This accounts for significant changes in the calculations of interest payable and interest earned by the retailer. The retailer's total cost is minimized so as to find out the optimal replenishment cycle time and price discount policies through a solution procedure. The results derived in mathematical theorems are implemented in numerical examples and sensitivity analyses on several inventory parameters are obtained.
Thermal stability of partially ordered Fe16N2 film on non-magnetic Ag under layer
NASA Astrophysics Data System (ADS)
Zhang, Xiaowei; Yang, Meiyin; Jiang, Yanfeng; Allard, Lawrence F.; Wang, Jian-Ping
2014-05-01
Partially ordered Fe16N2 thin film with (001) texture is successfully grown on a Ag under layer using a facing target sputtering system. Fe16N2 phase is formed after post-annealing, which is detected by X-ray diffraction (XRD). High saturation magnetization (Ms) of Fe16N2 thin films is observed by vibrating sample magnetometry. It is found that Fe16N2 phase can be stable up to 225 °C, which is demonstrated by the Fe16N2 finger print peak (002) in XRD. After heating to 250 °C, the Fe16N2 phase decomposes, which leads to low Ms and soft magnetic behavior. To further study Fe16N2 decomposition, X-ray photoelectron spectroscopy is performed to detect the binding energy of nitrogen atoms. Differences of binding energy corresponding to before and after heat treatment show the variation of nitrogen atom in electronic state with surrounding Fe atoms, indicating nitrogen atomic migration during heat treatment.
NASA Technical Reports Server (NTRS)
Galindo-Israel, V.; Imbriale, W.; Shogen, K.; Mittra, R.
1990-01-01
In obtaining solutions to the first-order nonlinear partial differential equations (PDEs) for synthesizing offset dual-shaped reflectors, it is found that previously observed computational problems can be avoided if the integration of the PDEs is started from an inner projected perimeter and integrated outward rather than starting from an outer projected perimeter and integrating inward. This procedure, however, introduces a new parameter, the main reflector inner perimeter radius p(o), when given a subreflector inner angle 0(o). Furthermore, a desired outer projected perimeter (e.g., a circle) is no longer guaranteed. Stability of the integration is maintained if some of the initial parameters are determined first from an approximate solution to the PDEs. A one-, two-, or three-parameter optimization algorithm can then be used to obtain a best set of parameters yielding a close fit to the desired projected outer rim. Good low cross-polarization mapping functions are also obtained. These methods are illustrated by synthesis of a high-gain offset-shaped Cassegrainian antenna and a low-noise offset-shaped Gregorian antenna.
NASA Technical Reports Server (NTRS)
Salama, A. M.; Ross, R. G., Jr.
1973-01-01
Comparison of two methods, namely Nedler and Mead's (1965) simplex method and Davidon's (1959) variable metric method, for achieving optimum design in terms of minimum weight for rotational shells under certain constraints. The superiority of one of the methods over the other is shown to depend, among other things, upon the form of the function to be minimized, and whether or not it is continuous everywhere in values and derivatives.
Optimum hovering wing planform.
Nabawy, Mostafa R A; Crowther, William J
2016-10-01
Theoretical analysis is used to identify the optimum wing planform of a flapping/revolving wing in hover. This solution is of interest as a benchmark to which hovering wing geometries driven by broader multidisciplinary evolutionary or engineering constraints can be compared. Furthermore, useful insights into the aerodynamic performance of untwisted hovering wings are delivered. It is shown that profile power is minimised by using an untwisted elliptical planform whereas induced power is minimised by a more highly tapered planform similar to that of a hummingbird. PMID:27329340
Hemdan, A
2016-07-01
Three simple, selective, and accurate spectrophotometric methods have been developed and then validated for the analysis of Benazepril (BENZ) and Amlodipine (AML) in bulk powder and pharmaceutical dosage form. The first method is the absorption factor (AF) for zero order and amplitude factor (P-F) for first order spectrum, where both BENZ and AML can be measured from their resolved zero order spectra at 238nm or from their first order spectra at 253nm. The second method is the constant multiplication coupled with constant subtraction (CM-CS) for zero order and successive derivative subtraction-constant multiplication (SDS-CM) for first order spectrum, where both BENZ and AML can be measured from their resolved zero order spectra at 240nm and 238nm, respectively, or from their first order spectra at 214nm and 253nm for Benazepril and Amlodipine respectively. The third method is the novel constant multiplication coupled with derivative zero crossing (CM-DZC) which is a stability indicating assay method for determination of Benazepril and Amlodipine in presence of the main degradation product of Benazepril which is Benazeprilate (BENZT). The three methods were validated as per the ICH guidelines and the standard curves were found to be linear in the range of 5-60μg/mL for Benazepril and 5-30 for Amlodipine, with well accepted mean correlation coefficient for each analyte. The intra-day and inter-day precision and accuracy results were well within the acceptable limits. PMID:27078209
NASA Astrophysics Data System (ADS)
Hemdan, A.
2016-07-01
Three simple, selective, and accurate spectrophotometric methods have been developed and then validated for the analysis of Benazepril (BENZ) and Amlodipine (AML) in bulk powder and pharmaceutical dosage form. The first method is the absorption factor (AF) for zero order and amplitude factor (P-F) for first order spectrum, where both BENZ and AML can be measured from their resolved zero order spectra at 238 nm or from their first order spectra at 253 nm. The second method is the constant multiplication coupled with constant subtraction (CM-CS) for zero order and successive derivative subtraction-constant multiplication (SDS-CM) for first order spectrum, where both BENZ and AML can be measured from their resolved zero order spectra at 240 nm and 238 nm, respectively, or from their first order spectra at 214 nm and 253 nm for Benazepril and Amlodipine respectively. The third method is the novel constant multiplication coupled with derivative zero crossing (CM-DZC) which is a stability indicating assay method for determination of Benazepril and Amlodipine in presence of the main degradation product of Benazepril which is Benazeprilate (BENZT). The three methods were validated as per the ICH guidelines and the standard curves were found to be linear in the range of 5-60 μg/mL for Benazepril and 5-30 for Amlodipine, with well accepted mean correlation coefficient for each analyte. The intra-day and inter-day precision and accuracy results were well within the acceptable limits.
NASA Technical Reports Server (NTRS)
Gayley, K. G.
1992-01-01
Approximate analytic expressions are derived for resonance-line wing diagnostics, accounting for frequency redistribution effects, for homogeneous slabs, and slabs with a constant Planck function gradient. Resonance-line emission profiles from a simplified conceptual standpoint are described in order to elucidate the basic physical parameters of the line-forming layers prior to the performance of detailed numerical calculations. An approximate analytic expression is derived for the dependence on stellar surface gravity of the location of the Ca II and Mg II resonance-line profile peaks. An approximate radiative transfer equation using generalized second-order escape probabilities, applicable even in the presence of nearly coherent scattering in the damping wings of resonance lines, is derived. Approximate analytic solutions that can be applied in special regimes and achieve good agreement with accurate numerical results are found.
Carlton, Rebecca J; Zayas-Gonzalez, Yashira M; Manna, Uttam; Lynn, David M; Abbott, Nicholas L
2014-12-16
We report a study of the wetting and ordering of thermotropic liquid crystal (LC) droplets that are trapped (or "caged") within micrometer-sized cationic polymeric microcapsules dispersed in aqueous solutions of surfactants. When they were initially dispersed in water, we observed caged, nearly spherical droplets of E7, a nematic LC mixture, to occupy ∼40% of the interior volume of the polymeric capsules [diameter of 6.7 ± 0.3 μm, formed via covalent layer-by-layer assembly of branched polyethylenimine and poly(2-vinyl-4,4-dimethylazlactone)] and to contact the interior surface of the capsule wall at an angle of ∼157 ± 11°. The internal ordering of LC within the droplets corresponded to the so-called bipolar configuration (distorted by contact with the capsule walls). While the effects of dodecyltrimethylammonium bromide (DTAB) and sodium dodecyl sulfate (SDS) on the internal ordering of "free" LC droplets are similar, we observed the two surfactants to trigger strikingly different wetting and configurational transitions when LC droplets were caged within polymeric capsules. Specifically, upon addition of SDS to the aqueous phase, we observed the contact angles (θ) of caged LC on the interior surface of the capsule to decrease, resulting in a progression of complex droplet shapes, including lenses (θ ≈ 130 ± 10°), hemispheres (θ ≈ 89 ± 5°), and concave hemispheres (θ < 85°). The wetting transitions induced by SDS also resulted in changes in the internal ordering of the LC to yield states topologically equivalent to axial and radial configurations. Although topologically equivalent to free droplets, the contributions that surface anchoring, LC elasticity, and topological defects make to the free energy of caged LC droplets differ from those of free droplets. Overall, these results and others reported herein lead us to conclude that caged LC droplets offer a platform for new designs of LC-droplet-based responsive soft matter that cannot be
Crystal structure and partial Ising-like magnetic ordering of orthorhombic D y2Ti O5
NASA Astrophysics Data System (ADS)
Shamblin, Jacob; Calder, Stuart; Dun, Zhiling; Lee, Minseong; Choi, Eun Sang; Neuefeind, Joerg; Zhou, Haidong; Lang, Maik
2016-07-01
The structure and magnetic properties of orthorhombic D y2Ti O5 have been investigated using x-ray diffraction, neutron diffraction, and alternating current (ac)/direct current (dc) magnetic susceptibility measurements. We report a continuous structural distortion below 100 K characterized by negative thermal expansion in the [0 1 0] direction. Neutron diffraction and magnetic susceptibility measurements revealed that two-dimensional (2D) magnetic ordering begins at 3.1 K, which is followed by a three-dimensional magnetic transition at 1.7 K. The magnetic structure has been solved through a representational analysis approach and can be indexed with the propagation vector k =[0 1 /2 0 ] . The spin structure corresponds to a coplanar model of interwoven 2D "sheets" extending in the [0 1 0] direction. The local crystal field is different for each D y3 + ion (Dy1 and Dy2), one of which possesses strong uniaxial symmetry indicative of Ising-like magnetic ordering. Consequently, two succeeding transitions under magnetic field are observed in the ac susceptibility, which are associated with flipping each D y3 + spin independently.
NASA Astrophysics Data System (ADS)
Zhang, Bin; Liu, Chen; Kong, Weiping; Qi, Chenze
2016-06-01
Magnetically active, ordered and stable mesoporous carbons with partially graphitized networks and controllable surface wettability (PR-Fe-P123-800 and PR-Ni-P123-800) have been synthesized through direct carbonization of Fe or Ni functionalized, and ordered mesoporous polymers at 800°C, which could be synthesized from self assembly of resol (phenol/formaldehyde) with block copolymer template (P123) in presence of Fe3+ or Ni2+, and hydrothermal treatment at 200°C. PR-Fe-P123-800 and PR-Ni-P123-800 possess ordered and uniform mesopores, large BET surface areas, good stabilities, controllable surface wettability and partially graphitized framework. The above structural characteristics result in their enhanced selective adsorption property and good reusability for organic pollutants such as RhB, p-nitrophenol and n-heptane in water, which could be easily regenerated through separation under constant magnetic fields and washing with ethanol solvent. The unique magnetically active and adsorptive property found in PR-Fe-P123-800 and PR-Ni-P123-800 will be very important for them to be used as efficient absorbents for removal of various organic pollutants in water.
NASA Astrophysics Data System (ADS)
Karagulyan, G. A.
1994-02-01
Random measures of the form \\displaystyle \\sum_{i=1}^\\infty m_i\\delta_{\\theta_i},\\qquad \\sum_{i=1}^\\infty \\vert m_i\\vert<\\infty,are considered, where \\delta_{\\theta_i} is a unit mass concentrated at the point \\theta_i\\in(0;\\,2\\pi). For any sequence of natural numbers \\{l_k\\}_{k=1}^\\infty it is established that for almost all sequences \\theta=\\{\\theta_i\\}_{i=1}^\\infty the partial sums S_{l_k}(x;\\,d\\mu_{\\theta}) of the Fourier-Stieltjes series of the measure have order o(\\log\\log k) for almost all x\\in(0;\\,2\\pi). As proved by Kahane in 1961, the order o(\\log\\log k) cannot be improved. This result is connected with the well-known problem of Zygmund of finding the exact order of growth of the partial sums of Fourier series almost everywhere.Bibliography: 15 titles.
NASA Astrophysics Data System (ADS)
Zhang, Bin; Liu, Chen; Kong, Weiping; Qi, Chenze
2016-02-01
Magnetically active, ordered and stable mesoporous carbons with partially graphitized networks and controllable surface wettability (PR-Fe-P123-800 and PR-Ni-P123-800) have been synthesized through direct carbonization of Fe or Ni functionalized, and ordered mesoporous polymers at 800°C, which could be synthesized from self assembly of resol (phenol/formaldehyde) with block copolymer template (P123) in presence of Fe3+ or Ni2+, and hydrothermal treatment at 200°C. PR-Fe-P123-800 and PR-Ni-P123-800 possess ordered and uniform mesopores, large BET surface areas, good stabilities, controllable surface wettability and partially graphitized framework. The above structural characteristics result in their enhanced selective adsorption property and good reusability for organic pollutants such as RhB, p-nitrophenol and n-heptane in water, which could be easily regenerated through separation under constant magnetic fields and washing with ethanol solvent. The unique magnetically active and adsorptive property found in PR-Fe-P123-800 and PR-Ni-P123-800 will be very important for them to be used as efficient absorbents for removal of various organic pollutants in water.
''Optimum productivity'': a geneticist's view
Libby, W.J.
1980-01-01
Both ''optimum'' and ''productivity'' are explored in a social context with a long time dimension. Renewability, flexibility, and diversity are important concepts in long-term planning to achieve optimum productivity. Various possible genetic contributions, including complementary clones, quantitative genetic engineering, resistant trees and plantations, elimination of inbreeding, single-gene genetic engineering, and agri-forestry, are suggested for long-term sustained or increased productivity.
Physical Meaning of the Optimum Measurement Process in Quantum Detection Theory
NASA Technical Reports Server (NTRS)
Osaki, Masao; Kozuka, Haruhisa; Hirota, Osamu
1996-01-01
The optimum measurement processes are represented as the optimum detection operators in the quantum detection theory. The error probability by the optimum detection operators goes beyond the standard quantum limit automatically. However the optimum detection operators are given by pure mathematical descriptions. In order to realize a communication system overcoming the standard quantum limit, we try to give the physical meaning of the optimum detection operators.
Laiho, Jack; Soni, Amarjit
2005-01-01
We show that it is possible to construct {epsilon}{sup '}/{epsilon} to next-to-leading order (NLO) using partially quenched chiral perturbation theory (PQChPT) from amplitudes that are computable on the lattice. We demonstrate that none of the needed amplitudes require 3-momentum on the lattice for either the full theory or the partially quenched theory; nondegenerate quark masses suffice. Furthermore, we find that the electro-weak penguin ({delta}I=3/2 and 1/2) contributions to {epsilon}{sup '}/{epsilon} in PQChPT can be determined to NLO using only degenerate (m{sub K}=m{sub {pi}}) K{yields}{pi} computations without momentum insertion. Issues pertaining to power divergent contributions, originating from mixing with lower dimensional operators, are addressed. Direct calculations of K{yields}{pi}{pi} at unphysical kinematics are plagued with enhanced finite volume effects in the (partially) quenched theory, but in simulations when the sea quark mass is equal to the up and down quark mass the enhanced finite volume effects vanish to NLO in PQChPT. In embedding the QCD penguin left-right operator onto PQChPT an ambiguity arises, as first emphasized by Golterman and Pallante. With one version [the 'PQS' (patially quenched singlet)] of the QCD penguin, the inputs needed from the lattice for constructing K{yields}{pi}{pi} at NLO in PQChPT coincide with those needed for the full theory. Explicit expressions for the finite logarithms emerging from our NLO analysis to the above amplitudes also are given.
Partial Orders Cannot Be Measured
ERIC Educational Resources Information Center
Kyngdon, Andrew
2011-01-01
Black, Wilson, and Yao (this issue) commendably attempt to put descriptive theory at the center of pedagogy, assessment, and curriculum. The thrust of their article is that only through theories of learning will student progression be properly understood. Casting a critical eye over the faddish distinction between "formative" and "summative"…
Cabral, Katia M S; Raymundo, Diana P; Silva, Viviane S; Sampaio, Laura A G; Johanson, Laizes; Hill, Luis Fernando; Almeida, Fabio C L; Cordeiro, Yraima; Almeida, Marcius S
2015-01-01
BEX3 (Brain Expressed X-linked protein 3) is a member of a mammal-specific placental protein family. Several studies have found the BEX proteins to be associated with neurodegeneration, the cell cycle and cancer. BEX3 has been predicted to be intrinsically disordered and also to represent an intracellular hub for cell signaling. The pro-apoptotic activity of BEX3 in association with a number of additional proteins has been widely supported; however, to the best of our knowledge, very limited data are available on the conformation of any of the members of the BEX family. In this study, we structurally characterized BEX3 using biophysical experimental data. Small angle X-ray scattering and atomic force microscopy revealed that BEX3 forms a specific higher-order oligomer that is consistent with a globular molecule. Solution nuclear magnetic resonance, partial proteinase K digestion, circular dichroism spectroscopy, and fluorescence techniques that were performed on the recombinant protein indicated that the structure of BEX3 is composed of approximately 31% α-helix and 20% β-strand, contains partially folded regions near the N- and C-termini, and a core which is proteolysis-resistant around residues 55-120. The self-oligomerization of BEX3 has been previously reported in cell culture and is consistent with our in vitro data. PMID:26383250
Sampaio, Laura A. G.; Johanson, Laizes; Hill, Luis Fernando; Almeida, Fabio C. L.; Cordeiro, Yraima; Almeida, Marcius S.
2015-01-01
BEX3 (Brain Expressed X–linked protein 3) is a member of a mammal-specific placental protein family. Several studies have found the BEX proteins to be associated with neurodegeneration, the cell cycle and cancer. BEX3 has been predicted to be intrinsically disordered and also to represent an intracellular hub for cell signaling. The pro-apoptotic activity of BEX3 in association with a number of additional proteins has been widely supported; however, to the best of our knowledge, very limited data are available on the conformation of any of the members of the BEX family. In this study, we structurally characterized BEX3 using biophysical experimental data. Small angle X-ray scattering and atomic force microscopy revealed that BEX3 forms a specific higher-order oligomer that is consistent with a globular molecule. Solution nuclear magnetic resonance, partial proteinase K digestion, circular dichroism spectroscopy, and fluorescence techniques that were performed on the recombinant protein indicated that the structure of BEX3 is composed of approximately 31% α-helix and 20% β-strand, contains partially folded regions near the N- and C-termini, and a core which is proteolysis-resistant around residues 55–120. The self-oligomerization of BEX3 has been previously reported in cell culture and is consistent with our in vitro data. PMID:26383250
NASA Astrophysics Data System (ADS)
Kobayashi, S.; Mitsuda, S.; Ishikawa, M.; Miyatani, K.; Kohn, K.
1999-08-01
The formation of three-dimensional magnetic ordering has been studied on a quasi-one-dimensional magnet CoNb2O6 by mean-field calculations as well as neutron scattering measurements down to T=1.5 K under magnetic fields up to H∥c~600 Oe. Measurements of a deviation of the magnetic Bragg scattering function from the delta function in the ordered state reveal a surprisingly rich variety of the magnetic formation arising from an isosceles triangular arrangement of the magnetic chain with competing interchain interactions in the a-b plane. The competing interactions result in quasidegenerate ground states with different propagation wave numbers along the b* direction in the sinusoidally amplitude-modulated incommensurate magnetic (IC) phase. Our mean-field calculations qualitatively reproduce the complicated H∥c-T magnetic phase diagram and give evidence for a high degeneracy of ground states by calculating the H∥c-T dependence of the free energy curve in the propagation wave number space. In addition, a partial cancellation of the exchange field at the apex site from the base sites on the isosceles triangular lattice leads to a quasi-long-range ordering along the a axis in both IC and antiferromagnetic states where the correlation length along the a axis depends on the propagation wave number along the b* direction.
Yang, Meiyin; Allard, Lawrence F.; Ji, Nian; Zhang, Xiaowei; Wang, Jian-Ping; Yu, Guang-Hua
2013-12-09
Partially ordered Fe-N thin films were grown by a facing target sputtering process on the surface of a (001) Ag underlayer on MgO substrates. It was confirmed by x-ray diffraction that the Ag layer enlarged the in-plane lattice of the Fe-N thin films. Domains of the ordered α″-Fe{sub 16}N{sub 2} phase within an epitaxial (001) α′-Fe{sub x}N phase were identified by electron diffraction and high-resolution aberration-corrected scanning transmission electron microscopy (STEM) methods. STEM dark-field and bright-field images showed the fully ordered structure of the α″-Fe{sub 16}N{sub 2} at the atomic column level. High saturation magnetization(Ms) of 1890 emu/cc was obtained for α″-Fe{sub 16}N{sub 2} on the Ag underlayer, while only 1500 emu/cc was measured for Fe-N on the Fe underlayer. The results are likely due to a tensile strain induced in the α″-Fe{sub 16}N{sub 2} phase by the Ag structure at the interface.
OPTIMUM FREQUENCY OF CALIBRATION MONITORING
The paper develops an algorithm by which to compute the optimal frequency of calibration monitoring to minimize the total cost of analyzing a set of samples and the required calibration standards. Optimum calibration monitoring is needed because of the high cost and calibration d...
Lozano, Valeria A; Ibañez, Gabriela A; Olivieri, Alejandro C
2010-06-01
Analyte quantitation can be achieved from second-order data in the presence of uncalibrated components using multivariate calibration methods such as partial least-squares with residual bilinearization. However, the latter fails under conditions of identical profiles for interfering agents and calibrated components in one of the data dimensions. To overcome this problem, a new residual bilinearization procedure for linear dependency is here introduced. Simulated data show that the new model can conveniently handle the studied analytical problem, with a success comparable to multivariate curve resolution-alternating least-squares and also comparable to a version of parallel factor analysis adapted to cope with linear dependencies. The new approach has also been applied to two experimental examples involving the determination of the antibiotic ciprofloxacin in (1) urine samples from lanthanide-sensitized excitation-time decay matrixes and (2) serum samples from a novel second-order signal based on the time evolution of chemiluminescence emission. The results indicate good analytical performance of the new procedure toward the analyte in comparison with the classical approaches. PMID:20443548
Sutton, Jonathan E.; Beste, Ariana; Steven H. Overbury
2015-10-12
In this study, we use density functional theory to explain the preferred structure of partially reduced CeO_{2}(111). Low-energy ordered structures are formed when the vacancies are isolated (maximized intervacancy separation) and the size of the Ce^{3+} ions is minimized. Both conditions help minimize disruptions to the lattice around the vacancy. The stability of the ordered structures suggests that isolated vacancies are adequate for modeling more complex (e.g., catalytic) systems. Oxygen diffusion barriers are predicted to be low enough that O diffusion between vacancies is thermodynamically controlled at room temperature. The O-diffusion-reaction energies and barriers are decreased when one Ce f electron hops from a nearest-neighbor Ce cation to a next-nearest-neighbor Ce cation, with a barrier that has been estimated to be slightly less than the barrier to O diffusion in the absence of polaron hopping. In conculsion, this indicates that polaron hopping plays a key role in facilitating the overall O diffusion process, and depending on the relative magnitudes of the polaron hopping and O diffusion barriers, polaron hopping may be the kinetically limiting process.
Sutton, Jonathan E.; Beste, Ariana; Steven H. Overbury
2015-10-12
In this study, we use density functional theory to explain the preferred structure of partially reduced CeO2(111). Low-energy ordered structures are formed when the vacancies are isolated (maximized intervacancy separation) and the size of the Ce3+ ions is minimized. Both conditions help minimize disruptions to the lattice around the vacancy. The stability of the ordered structures suggests that isolated vacancies are adequate for modeling more complex (e.g., catalytic) systems. Oxygen diffusion barriers are predicted to be low enough that O diffusion between vacancies is thermodynamically controlled at room temperature. The O-diffusion-reaction energies and barriers are decreased when one Ce fmore » electron hops from a nearest-neighbor Ce cation to a next-nearest-neighbor Ce cation, with a barrier that has been estimated to be slightly less than the barrier to O diffusion in the absence of polaron hopping. In conculsion, this indicates that polaron hopping plays a key role in facilitating the overall O diffusion process, and depending on the relative magnitudes of the polaron hopping and O diffusion barriers, polaron hopping may be the kinetically limiting process.« less
Optimum conditions for adsorptive storage.
Bhatia, Suresh K; Myers, Alan L
2006-02-14
The storage of gases in porous adsorbents, such as activated carbon and carbon nanotubes, is examined here thermodynamically from a systems viewpoint, considering the entire adsorption-desorption cycle. The results provide concrete objective criteria to guide the search for the "Holy Grail" adsorbent, for which the adsorptive delivery is maximized. It is shown that, for ambient temperature storage of hydrogen and delivery between 30 and 1.5 bar pressure, for the optimum adsorbent the adsorption enthalpy change is 15.1 kJ/mol. For carbons, for which the average enthalpy change is typically 5.8 kJ/mol, an optimum operating temperature of about 115 K is predicted. For methane, an optimum enthalpy change of 18.8 kJ/mol is found, with the optimum temperature for carbons being 254 K. It is also demonstrated that for maximum delivery of the gas the optimum adsorbent must be homogeneous, and that introduction of heterogeneity, such as by ball milling, irradiation, and other means, can only provide small increases in physisorption-related delivery for hydrogen. For methane, heterogeneity is always detrimental, at any value of average adsorption enthalpy change. These results are confirmed with the help of experimental data from the literature, as well as extensive Monte Carlo simulations conducted here using slit pore models of activated carbons as well as atomistic models of carbon nanotubes. The simulations also demonstrate that carbon nanotubes offer little or no advantage over activated carbons in terms of enhanced delivery, when used as storage media for either hydrogen or methane. PMID:16460092
Optimum windmill-site matching
Salameh, Z.M.; Safari, I. )
1992-12-01
In this paper a methodology for the selection of the optimum windmill for a specific site is developed. The selection windmill for a specific site is developed. The selection is based on finding the capacity factors (CF) of the available windmills. This is done by using long term wind speed data recorded at different hours of the day for many years. This data is then used to generate mean wind speeds for a typical day in a month. Probability density functions for the mean wind speeds for the different hours of the day are generated with the manufacturer's specifications on windmills used to calculate the capacity factors for the windmills. The windmill with the highest average capacity factor for the specific site is the optimum one and to be recommended.
Draeger, Guenter; Machek, Pavel
2003-01-24
We report the first experimental spin projections of empty partial density of states in antiferromagnetic NiO and CuO, paramagnetic MnO and in ferrimagnetic Dy3Fe5O12 by means of resonant X-ray scattering (RXS). Resolving resonantly scattered K{alpha}1,2 , K{beta}1,3 , L{alpha}1 and L1 core line spectra into their spin-up and spin-down components the spin character of the dipole- and quadrupole-excited conduction band states can quantitatively be analyzed. Since the method employs spin conservation in the RXS process and local spin references, it needs neither circularly polarized radiation nor sample magnetization for measuring the spectra. Hence, antiferro- and paramagnetic materials can be investigated as well. In the paper, the basic idea of the novel method, its experimental realization and the data treatment are reported including the spectra decomposition into the spin-up and spin-down components by using Principal Component Analysis (PCA). New and unambiguous results will be presented providing the opportunity to verify experimentally the results of spin-dependent (LSDA+U) calculations. So we argue the new spectroscopy complements X-ray magnetic dichroism, which is silent for antiferro- and paramagnetic materials. In fact, the novel method gives insight into the spin polarization of conduction band states in correlated materials, independently on their magnetic ordering.
Thermal stability of partially ordered Fe{sub 16}N{sub 2} film on non-magnetic Ag under layer
Zhang, Xiaowei; Wang, Jian-Ping; Yang, Meiyin; Jiang, Yanfeng; Allard, Lawrence F.
2014-05-07
Partially ordered Fe{sub 16}N{sub 2} thin film with (001) texture is successfully grown on a Ag under layer using a facing target sputtering system. Fe{sub 16}N{sub 2} phase is formed after post-annealing, which is detected by X-ray diffraction (XRD). High saturation magnetization (M{sub s}) of Fe{sub 16}N{sub 2} thin films is observed by vibrating sample magnetometry. It is found that Fe{sub 16}N{sub 2} phase can be stable up to 225 °C, which is demonstrated by the Fe{sub 16}N{sub 2} finger print peak (002) in XRD. After heating to 250 °C, the Fe{sub 16}N{sub 2} phase decomposes, which leads to low M{sub s} and soft magnetic behavior. To further study Fe{sub 16}N{sub 2} decomposition, X-ray photoelectron spectroscopy is performed to detect the binding energy of nitrogen atoms. Differences of binding energy corresponding to before and after heat treatment show the variation of nitrogen atom in electronic state with surrounding Fe atoms, indicating nitrogen atomic migration during heat treatment.
Swarms: Optimum aggregations of spacecraft
NASA Technical Reports Server (NTRS)
Mayer, H. L.
1980-01-01
Swarms are aggregations of spacecraft or elements of a space system which are cooperative in function, but physically isolated or only loosely connected. For some missions the swarm configuration may be optimum compared to a group of completely independent spacecraft or a complex rigidly integrated spacecraft or space platform. General features of swarms are induced by considering an ensemble of 26 swarms, examples ranging from Earth centered swarms for commercial application to swarms for exploring minor planets. A concept for a low altitude swarm as a substitute for a space platform is proposed and a preliminary design studied. The salient design feature is the web of tethers holding the 30 km swarm in a rigid two dimensional array in the orbital plane. A mathematical discussion and tutorial in tether technology and in some aspects of the distribution of services (mass, energy, and information to swarm elements) are included.
Optimum constrained image restoration filters
NASA Technical Reports Server (NTRS)
Riemer, T. E.; Mcgillem, C. D.
1974-01-01
The filter was developed in Hilbert space by minimizing the radius of gyration of the overall or composite system point-spread function subject to constraints on the radius of gyration of the restoration filter point-spread function, the total noise power in the restored image, and the shape of the composite system frequency spectrum. An iterative technique is introduced which alters the shape of the optimum composite system point-spread function, producing a suboptimal restoration filter which suppresses undesirable secondary oscillations. Finally this technique is applied to multispectral scanner data obtained from the Earth Resources Technology Satellite to provide resolution enhancement. An experimental approach to the problems involving estimation of the effective scanner aperture and matching the ERTS data to available restoration functions is presented.
Optimum nonparametric estimation of population density based on ordered distances
Patil, S.A.; Kovner, J.L.; Burnham, Kenneth P.
1982-01-01
The asymptotic mean and error mean square are determined for the nonparametric estimator of plant density by distance sampling proposed by Patil, Burnham and Kovner (1979, Biometrics 35, 597-604. On the basis of these formulae, a bias-reduced version of this estimator is given, and its specific form is determined which gives minimum mean square error under varying assumptions about the true probability density function of the sampled data. Extension is given to line-transect sampling.
Optimum frequency assignment for satellite SCPC systems
NASA Astrophysics Data System (ADS)
Okinaka, H.; Yasuda, Y.; Hirata, Y.
A technique for deriving a quasi-optimum solution for IM-minimum channel allocation for single-level SCPC systems is presented. Two types of IM products are considered as the dominant components in an RF band. The third order IM product is proportional to the product of the power of concerned carriers, allowing a weighting function to be defined for calculating the IM noise. An IM minimum channel allocation technique can then be used to reduce the IM noise occurring in the carrier slots through frequency assignment. The worst carrier is automatically deleted with an initial channel allocation and the process is iterated until the maximum noise reduction is obtained. The first two or three carriers are assigned to unused frequency slots with low noise. The method is also viable when dealing with a larger number of carriers.
The optimum hypersonic wind tunnel
NASA Technical Reports Server (NTRS)
Trimmer, L. L.; Cary, A., Jr.; Voisinet, R. L. P.
1986-01-01
The capabilities of existing hypersonic wind tunnels in the U.S. are assessed to form a basis for recommendations for a new, costly facility which would provide data for modeling the hypervelocity aerodynamics envisioned for the new generation of aerospace vehicles now undergoing early studies. Attention is given to the regimes, both entry and aerodynamic, which the new vehicles will encounter, and the shortcomings of data generated for the Orbiter before flight are discussed. The features of foreign-gas, impulse, aeroballistic range, arc-heated and combustion-heated facilities are examined, noting that in any hypersonic wind tunnel the flow must be preheated to prevent liquefaction upon expansion in the test channel. The limitations of the existing facilities and the identification of the regimes which must be studied lead to a description of the characteristics of an optimum hypersonic wind tunnel, including the operations and productivity, the instrumentation, the nozzle design and the flow quality. Three different design approaches are described, each costing at least $100 million to achieve workability.
NICMOS Optimum Coronagraphic Focus Determinaton
NASA Astrophysics Data System (ADS)
Schneider, Glenn
1997-07-01
This test will ascertain the optimum position of the PAM for maximizing the local contrast ratios in coronagraphic images. Because of the forward motion of the NICMOS optical bench and dewar, the nominal operational position for the PAM is set {for each camera} to achieve diffraction limited focus at the image plane formed at the detector. As a result of the forward motion of the camera 2 detector, hard images are no longer formed coincidentally at the field divider mirror surface {where the coronagraphic hole is located} and at the detector. This will lead to an increase in the diffracted energy in the wings of a PSF from a target placed inside of the coronagraphic hole as the image plane will fall behind the surface of the FDA mirror. The contrast in a coronagraphic image might be enhanced by placing the focus to form an image at either image planes {FDA or detector} or at a place in-between. This is highly dependent on scattering and must be ascertained by direct measurement.
Optimum orientation versus orientation averaging description of cluster radioactivity
NASA Astrophysics Data System (ADS)
Seif, W. M.; Ismail, M.; Refaie, A. I.; Amer, Laila H.
2016-07-01
While the optimum-orientation concept is frequently used in studies on cluster decays involving deformed nuclei, the orientation-averaging concept is used in most alpha decay studies. We investigate the different decay stages in both the optimum-orientation and the orientation-averaging pictures of the cluster decay process. For decays of 232,233,234U and 236,238Pu isotopes, the quantum knocking frequency and penetration probability based on the Wentzel–Kramers–Brillouin approximation are used to find the decay width. The obtained decay width and the experimental half-life are employed to estimate the clusters preformation probability. We found that the orientation-averaged decay width is one or two orders of magnitude less than its value along the non-compact optimum orientation. Correspondingly, the extracted preformation probability based on the averaged decay width increases with the same orders of magnitude compared to its value obtained considering the optimum orientation. The cluster preformation probabilities estimated by the two considered schemes are in more or less comparable agreement with the Blendowske–Walliser (BW) formula based on the preformation probability of α ({S}α {{a}{{v}}{{e}}}) obtained from the orientation-averaging scheme. All the results, including the optimum-orientation ones, deviate substantially from the BW law based on {S}α {{o}{{p}}{{t}}} that was estimated from the optimum-orientation scheme. To account for the nuclear deformations, it is more relevant to calculate the decay width by averaging over the different possible orientations of the participating deformed nuclei, rather than considering the corresponding non-compact optimum orientation.
Optimum reentry trajectories of a lifting vehicle
NASA Technical Reports Server (NTRS)
Chern, J. S.; Vinh, N. X.
1980-01-01
Research results are presented of an investigation of the optimum maneuvers of advanced shuttle type spacecraft during reentry. The equations are formulated by means of modified Chapman variables resulting in a general set of equations for flight analysis which are exact for reentry and for flight in a vacuum. Four planar flight typical optimum manuevers are investigated. For three-dimensional flight the optimum trajectory for maximum cross range is discussed in detail. Techniques for calculating reentry footprints are presented.
The research on the optimum working conditions of photoconductive antenna
NASA Astrophysics Data System (ADS)
Shi, Wei; Dai, Yang; Zhang, Like; Yang, Lei; Yan, Zhijin; Chen, Suguo; Hou, Lei
2015-11-01
The photoconductive antenna (PCA) is one of the most common devices to generate terahertz (THz) wave, whose radiation efficiency is largely determined by the working conditions. In order to improve the power of THz wave, the influence of pump laser and bias voltage on the intensity of the THz wave radiated by PCA was studied through experiment and the optimum working conditions of PCA was obtained through the theoretical analysis, these are the maximum safe voltage and saturated laser energy. Only under the optimum conditions can the signal-to-noise ratio(SNR)of THz wave radiated by PCA be the highest and the PCA would not breakdown.
Optimization of the AGS superconducting helical partial snake strength.
Lin,F.; Huang, H.; Luccio, A.U.; Roser, T.
2008-06-23
Two helical partial snakes, one super-conducting (a.k.a cold snake) and one normal conducting (a.k.a warm snake), have preserved the polarization of proton beam up to 65% in the Brookhaven Alternating Gradient Synchrotron (AGS) at the extraction energy from 85% at injection. In order to overcome spin resonances, stronger partial snakes would be required. However, the stronger the partial snake, the more the stable spin direction tilted producing a stronger horizontal intrinsic resonance. The balance between increasing the spin tune gap generated by the snakes and reducing the tilted stable spin direction has to be considered to maintain the polarization. Because the magnetic field of the warm snake has to be a constant, only the cold snake with a maximum 3T magnetic field can be varied to find out the optimum snake strength. This paper presents simulation results by spin tracking with different cold snake magnetic fields. Some experimental data are also analyzed.
Chizinski, Christopher J.; Vondracek, Bruce C.; Blinn, Charles R.; Newman, Raymond M.; Atuke, Dickson M.; Fredricks, Keith; Hemstad, Nathaniel A.; Merten, Eric; Schlesser, Nicholas
2010-01-01
Relatively few evaluations of aquatic macroinvertebrate and fish communities have been published in peer-reviewed literature detailing the effect of varying residual basal area (RBA) after timber harvesting in riparian buffers. Our analysis investigated the effects of partial harvesting within riparian buffers on aquatic macroinvertebrate and fish communities in small streams from two experiments in northern Minnesota northern hardwood-aspen forests. Each experiment evaluated partial harvesting within riparian buffers. In both experiments, benthic macroinvertebrates and fish were collected 1 year prior to harvest and in each of 3 years after harvest. We observed interannual variation for the macroinvertebrate abundance, diversity and taxon richness in the single-basin study and abundance and diversity in the multiple-basin study, but few effects related to harvest treatments in either study. However, interannual variation was not evident in the fish communities and we detected no significant changes in the stream fish communities associated with partially harvested riparian buffers in either study. This would suggest that timber harvesting in riparian management zones along reaches ≤200 m in length on both sides of the stream that retains RBA ≥ 12.4 ± 1.3 m2 ha−1 or on a single side of the stream that retains RBA ≥ 8.7 ± 1.6 m2 ha−1 may be adequate to protect macroinvertebrate and fish communities in our Minnesota study systems given these specific timber harvesting techniques.
Twisted partially pure spinors
NASA Astrophysics Data System (ADS)
Herrera, Rafael; Tellez, Ivan
2016-08-01
Motivated by the relationship between orthogonal complex structures and pure spinors, we define twisted partially pure spinors in order to characterize spinorially subspaces of Euclidean space endowed with a complex structure.
Optimum flight paths of turbojet aircraft
NASA Technical Reports Server (NTRS)
Miele, Angelo
1955-01-01
The climb of turbojet aircraft is analyzed and discussed including the accelerations. Three particular flight performances are examined: minimum time of climb, climb with minimum fuel consumption, and steepest climb. The theoretical results obtained from a previous study are put in a form that is suitable for application on the following simplifying assumptions: the Mach number is considered an independent variable instead of the velocity; the variations of the airplane mass due to fuel consumption are disregarded; the airplane polar is assumed to be parabolic; the path curvatures and the squares of the path angles are disregarded in the projection of the equation of motion on the normal to the path; lastly, an ideal turbojet with performance independent of the velocity is involved. The optimum Mach number for each flight condition is obtained from the solution of a sixth order equation in which the coefficients are functions of two fundamental parameters: the ratio of minimum drag in level flight to the thrust and the Mach number which represents the flight at constant altitude and maximum lift-drag ratio.
Optimum coding techniques for MST radars
NASA Technical Reports Server (NTRS)
Sulzer, M. P.; Woodman, R. F.
1986-01-01
The optimum coding technique for MST (mesosphere stratosphere troposphere) radars is that which gives the lowest possible sidelobes in practice and can be implemented without too much computing power. Coding techniques are described in Farley (1985). A technique mentioned briefly there but not fully developed and not in general use is discussed here. This is decoding by means of a filter which is not matched to the transmitted waveform, in order to reduce sidelobes below the level obtained with a matched filter. This is the first part of the technique discussed here; the second part consists of measuring the transmitted waveform and using it as the basis for the decoding filter, thus reducing errors due to imperfections in the transmitter. There are two limitations to this technique. The first is a small loss in signal to noise ratio (SNR), which usually is not significant. The second problem is related to incomplete information received at the lowest ranges. An appendix shows a technique for handling this problem. Finally, it is shown that the use of complementary codes on transmission and nonmatched decoding gives the lowest possible sidelobe level and the minimum loss in SNR due to mismatch.
Optimum culture in the cockpit
NASA Technical Reports Server (NTRS)
Yamamori, Hisaaki
1987-01-01
Even with the same program and objectives, if the culture is different, there will be different approaches to the goal of flight safety. However, the cockpit environment is culture-free so it is not as important to think of a person's cultural background as it is to think of the approach to the goal of ultimate safety. Crew members can look at their individual safety goals and compare them to their own performance to see if their behavior matches their own safety goals. The cockpit environment must be culture-free in order to obtain the ultimate safety goal. One must first realize how their culture affects their behavior before they can begin to change their attitude and actions in the cockpit.
NASA Technical Reports Server (NTRS)
Capps, Stephen; Lorandos, Jason; Akhidime, Eval; Bunch, Michael; Lund, Denise; Moore, Nathan; Murakawa, Kiosuke
1989-01-01
The purpose of this study is to investigate comprehensive design requirements associated with designing habitats for humans in a partial gravity environment, then to apply them to a lunar base design. Other potential sites for application include planetary surfaces such as Mars, variable-gravity research facilities, and a rotating spacecraft. Design requirements for partial gravity environments include locomotion changes in less than normal earth gravity; facility design issues, such as interior configuration, module diameter, and geometry; and volumetric requirements based on the previous as well as psychological issues involved in prolonged isolation. For application to a lunar base, it is necessary to study the exterior architecture and configuration to insure optimum circulation patterns while providing dual egress; radiation protection issues are addressed to provide a safe and healthy environment for the crew; and finally, the overall site is studied to locate all associated facilities in context with the habitat. Mission planning is not the purpose of this study; therefore, a Lockheed scenario is used as an outline for the lunar base application, which is then modified to meet the project needs. The goal of this report is to formulate facts on human reactions to partial gravity environments, derive design requirements based on these facts, and apply the requirements to a partial gravity situation which, for this study, was a lunar base.
Calimag-Williams, Korina; Knobel, Gaston; Goicoechea, H C; Campiglia, A D
2014-02-01
An attractive approach to handle matrix interference in samples of unknown composition is to generate second- or higher-order data formats and process them with appropriate chemometric algorithms. Several strategies exist to generate high-order data in fluorescence spectroscopy, including wavelength time matrices, excitation-emission matrices and time-resolved excitation-emission matrices. This article tackles a different aspect of generating high-order fluorescence data as it focuses on total synchronous fluorescence spectroscopy. This approach refers to recording synchronous fluorescence spectra at various wavelength offsets. Analogous to the concept of an excitation-emission data format, total synchronous data arrays fit into the category of second-order data. The main difference between them is the non-bilinear behavior of synchronous fluorescence data. Synchronous spectral profiles change with the wavelength offset used for sample excitation. The work presented here reports the first application of total synchronous fluorescence spectroscopy to the analysis of monohydroxy-polycyclic aromatic hydrocarbons in urine samples of unknown composition. Matrix interference is appropriately handled by processing the data either with unfolded-partial least squares and multi-way partial least squares, both followed by residual bi-linearization. PMID:24456595
Aero-optimum hovering kinematics.
Nabawy, Mostafa R A; Crowther, William J
2015-08-01
Hovering flight for flapping wing vehicles requires rapid and relatively complex reciprocating movement of a wing relative to a stationary surrounding fluid. This note develops a compact analytical aero-kinematic model that can be used for optimization of flapping wing kinematics against aerodynamic criteria of effectiveness (maximum lift) and efficiency (minimum power for a given amount of lift). It can also be used to make predictions of required flapping frequency for a given geometry and basic aerodynamic parameters. The kinematic treatment is based on a consolidation of an existing formulation that allows explicit derivation of flapping velocity for complex motions whereas the aerodynamic model is based on existing quasi-steady analysis. The combined aero-kinematic model provides novel explicit analytical expressions for both lift and power of a hovering wing in a compact form that enables exploration of a rich kinematic design space. Good agreement is found between model predictions of flapping frequency and observed results for a number of insects and optimal hovering kinematics identified using the model are consistent with results from studies using higher order computational models. For efficient flight, the flapping angle should vary using a triangular profile in time leading to a constant velocity flapping motion, whereas for maximum effectiveness the shape of variation should be sinusoidal. For both cases the wing pitching motion should be rectangular such that pitch change at stroke reversal is as rapid as possible. PMID:26248884
Optimum PWM waveform synthesis - a filtering approach
Divan, D.M.
1985-09-01
A fundamentally different approach is proposed for the synthesis of optimum pulsewidth modulated (PWM) waveforms for highpower inverter applications. Conventional optimum PWM waveform synthesis techniques which seek to control harmonic levels in the inverter output directly are seen to be equivalent to a filtering operation. Digital filter structures capable of processing PWM waveforms are examined and waveform synthesis strategies are proposed and verified experimentally. Finally, the design of a high-performance PWM waveform generator is detailed.
Thompson, Corey; Greedan, John; Garlea, Vasile O; Flacau, Roxana; Tan, Malinda; Derakhshan, Shahab
2014-01-01
The novel iron-based compound, BaYFeO4, crystallizes in the Pnma space group with two distinct Fe3+ sites, that are alternately corner-shared [FeO5]7 square pyramids and [FeO6]9 octahedra, forming into [Fe4O18]24 rings, which propagate as columns along the b-axis. A recent report shows two discernible antiferromagnetic (AFM) transitions at 36 and 48 K in the susceptibility, yet heat capacity measurements reveal no magnetic phase transitions at these temperatures. An upturn in the magnetic susceptibility measurements up to 400 K suggests the presence of shortrange magnetic behavior at higher temperatures. In this Article, variable-temperature neutron powder diffraction and hightemperature magnetic susceptibility measurements were performed to clarify the magnetic behavior. Neutron powder diffraction confirmed that the two magnetic transitions observed at 36 and 48 K are due to long-range magnetic order. Below 48 K, the magnetic structure was determined as a spin-density wave (SDW) with a propagation vector, k = (0, 0, 1/3), and the moments along the b-axis, whereas the structure becomes an incommensurate cycloid [k = (0, 0, 0.35)] below 36 K with the moments within the bc-plane. However, for both cases the ordered moments on Fe3+ are only of the order 3.0 B, smaller than the expected values near 4.5 B, indicating that significant components of the Fe moments remain paramagnetic to the lowest temperature studied, 6 K. Moreover, new high-temperature magnetic susceptibility measurements revealed a peak maximum at 550 K indicative of short-range spin correlations. It is postulated that most of the magnetic entropy is thus removed at high temperatures which could explain the absence of heat capacity anomalies at the long-range ordering temperatures. Published spin dimer calculations, which appear to suggest a k = (0, 0, 0) magnetic structure, and allow for neither low dimensionality nor geometric frustration, are inadequate to explain the observed complex magnetic
2015-01-01
We report a study of the wetting and ordering of thermotropic liquid crystal (LC) droplets that are trapped (or “caged”) within micrometer-sized cationic polymeric microcapsules dispersed in aqueous solutions of surfactants. When they were initially dispersed in water, we observed caged, nearly spherical droplets of E7, a nematic LC mixture, to occupy ∼40% of the interior volume of the polymeric capsules [diameter of 6.7 ± 0.3 μm, formed via covalent layer-by-layer assembly of branched polyethylenimine and poly(2-vinyl-4,4-dimethylazlactone)] and to contact the interior surface of the capsule wall at an angle of ∼157 ± 11°. The internal ordering of LC within the droplets corresponded to the so-called bipolar configuration (distorted by contact with the capsule walls). While the effects of dodecyltrimethylammonium bromide (DTAB) and sodium dodecyl sulfate (SDS) on the internal ordering of “free” LC droplets are similar, we observed the two surfactants to trigger strikingly different wetting and configurational transitions when LC droplets were caged within polymeric capsules. Specifically, upon addition of SDS to the aqueous phase, we observed the contact angles (θ) of caged LC on the interior surface of the capsule to decrease, resulting in a progression of complex droplet shapes, including lenses (θ ≈ 130 ± 10°), hemispheres (θ ≈ 89 ± 5°), and concave hemispheres (θ < 85°). The wetting transitions induced by SDS also resulted in changes in the internal ordering of the LC to yield states topologically equivalent to axial and radial configurations. Although topologically equivalent to free droplets, the contributions that surface anchoring, LC elasticity, and topological defects make to the free energy of caged LC droplets differ from those of free droplets. Overall, these results and others reported herein lead us to conclude that caged LC droplets offer a platform for new designs of LC-droplet-based responsive soft matter that cannot
Optimum design of structures subject to general periodic loads
NASA Technical Reports Server (NTRS)
Reiss, Robert; Qian, B.
1989-01-01
A simplified version of Icerman's problem regarding the design of structures subject to a single harmonic load is discussed. The nature of the restrictive conditions that must be placed on the design space in order to ensure an analytic optimum are discussed in detail. Icerman's problem is then extended to include multiple forcing functions with different driving frequencies. And the conditions that now must be placed upon the design space to ensure an analytic optimum are again discussed. An important finding is that all solutions to the optimality condition (analytic stationary design) are local optima, but the global optimum may well be non-analytic. The more general problem of distributing the fixed mass of a linear elastic structure subject to general periodic loads in order to minimize some measure of the steady state deflection is also considered. This response is explicitly expressed in terms of Green's functional and the abstract operators defining the structure. The optimality criterion is derived by differentiating the response with respect to the design parameters. The theory is applicable to finite element as well as distributed parameter models.
Study of optimum methods of optical communication
NASA Technical Reports Server (NTRS)
Harger, R. O.
1972-01-01
Optimum methods of optical communication accounting for the effects of the turbulent atmosphere and quantum mechanics, both by the semi-classical method and the full-fledged quantum theoretical model are described. A concerted effort to apply the techniques of communication theory to the novel problems of optical communication by a careful study of realistic models and their statistical descriptions, the finding of appropriate optimum structures and the calculation of their performance and, insofar as possible, comparing them to conventional and other suboptimal systems are discussed. In this unified way the bounds on performance and the structure of optimum communication systems for transmission of information, imaging, tracking, and estimation can be determined for optical channels.
Optimum Suction Distribution for Transition Control
NASA Technical Reports Server (NTRS)
Balakumar, P.; Hall, P.
1996-01-01
The optimum suction distribution which gives the longest laminar region for a given total suction is computed. The goal here is to provide the designer with a method to find the best suction distribution subject to some overall constraint applied to the suction. We formulate the problem using the Lagrangian multiplier method with constraints. The resulting non-linear system of equations is solved using the Newton-Raphson technique. The computations are performed for a Blasius boundary layer on a flat-plate and crossflow cases. For the Blasius boundary layer, the optimum suction distribution peaks upstream of the maximum growth rate region and remains flat in the middle before it decreases to zero at the end of the transition point. For the stationary and travelling crossflow instability, the optimum suction peaks upstream of the maximum growth rate region and decreases gradually to zero.
Optimum reentry trajectories of a lifting vehicle
NASA Technical Reports Server (NTRS)
Chern, J. S.; Vinh, N. X.
1978-01-01
The optimum maneuver of a space shuttle vehicle reentering a spherical, stationary, and locally exponential atmosphere was investigated. The use of Chapman's modified variables and a rescaled lift-drag polar leads to the formulation of a set of dimensionless equations of motion for flight analysis. The resulting equations are exact in the sense that they are also valid for flight in the vacuum. For planar flight several typical optimum maneuvers are investigated at different altitude ranges, low, moderate and very high. For three-dimensional flight, the procedure to solve the optimum trajectory for maximum cross range is discussed. Finally, using the equilibrium glide condition the maximum cross ranges for entry from circular speed, for several values of E*, and the footprint for E* = 1.5 are computed in this reduced problem.
Optimum viewing distance for target acquisition
NASA Astrophysics Data System (ADS)
Holst, Gerald C.
2015-05-01
Human visual system (HVS) "resolution" (a.k.a. visual acuity) varies with illumination level, target characteristics, and target contrast. For signage, computer displays, cell phones, and TVs a viewing distance and display size are selected. Then the number of display pixels is chosen such that each pixel subtends 1 min-1. Resolution of low contrast targets is quite different. It is best described by Barten's contrast sensitivity function. Target acquisition models predict maximum range when the display pixel subtends 3.3 min-1. The optimum viewing distance is nearly independent of magnification. Noise increases the optimum viewing distance.
Method for Determining Optimum Injector Inlet Geometry
NASA Technical Reports Server (NTRS)
Trinh, Huu P. (Inventor); Myers, W. Neill (Inventor)
2015-01-01
A method for determining the optimum inlet geometry of a liquid rocket engine swirl injector includes obtaining a throttleable level phase value, volume flow rate, chamber pressure, liquid propellant density, inlet injector pressure, desired target spray angle and desired target optimum delta pressure value between an inlet and a chamber for a plurality of engine stages. The method calculates the tangential inlet area for each throttleable stage. The method also uses correlation between the tangential inlet areas and delta pressure values to calculate the spring displacement and variable inlet geometry of a liquid rocket engine swirl injector.
DESIGN GUIDELINES FOR AN OPTIMUM SCRUBBER SYSTEM
The report gives results of a review of the performance and operating experience of existing utility scrubber systems and the state-of-the-art in design of scrubber components. It also gives guidelines for the design of the optimum wet scrubber system, based on this review. The U...
Optimum Building Shapes for Energy Conservation
ERIC Educational Resources Information Center
Berkoz, Esher Balkan
1977-01-01
An approach to optimum building shape design is summarized that is based on local climate and is especially important for heat control in lower cost construction with temperature-responsive thermal characteristics. The study was supported by Istanbul Technical University. For journal availability see HE 508 931. (Author/LBH)
Common Core: Teaching Optimum Topic Exploration (TOTE)
ERIC Educational Resources Information Center
Karge, Belinda Dunnick; Moore, Roxane Kushner
2015-01-01
The Common Core has become a household term and yet many educators do not understand what it means. This article explains the historical perspectives of the Common Core and gives guidance to teachers in application of Teaching Optimum Topic Exploration (TOTE) necessary for full implementation of the Common Core State Standards. An effective…
2011-01-01
Introduction About 3% of people will be diagnosed with epilepsy during their lifetime, but about 70% of people with epilepsy eventually go into remission. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of starting antiepileptic drug treatment following a single seizure? What are the effects of drug monotherapy in people with partial epilepsy? What are the effects of additional drug treatments in people with drug-resistant partial epilepsy? What is the risk of relapse in people in remission when withdrawing antiepileptic drugs? What are the effects of behavioural and psychological treatments for people with epilepsy? What are the effects of surgery in people with drug-resistant temporal lobe epilepsy? We searched: Medline, Embase, The Cochrane Library, and other important databases up to July 2009 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 83 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: antiepileptic drugs after a single seizure; monotherapy for partial epilepsy using carbamazepine, gabapentin, lamotrigine, levetiracetam, phenobarbital, phenytoin, sodium valproate, or topiramate; addition of second-line drugs for drug-resistant partial epilepsy (allopurinol, eslicarbazepine, gabapentin, lacosamide, lamotrigine, levetiracetam, losigamone, oxcarbazepine, retigabine, tiagabine, topiramate, vigabatrin, or zonisamide); antiepileptic drug withdrawal for people with partial or
An optimum solar wind coupling function for the AL index
NASA Astrophysics Data System (ADS)
McPherron, Robert L.; Hsu, Tung-Shin; Chu, Xiangning
2015-04-01
We define a coupling function as a product of solar wind factors that partially linearizes the relation between it and a magnetic index. We consider functions that are a product of factors of solar wind speed V, density N, transverse magnetic field B⊥, and interplanetary magnetic field (IMF) clock angle θc each raised to a different power. The index is the auroral lower (AL index) which monitors the strength of the westward electrojet. Solar wind data 1995-2014 provide hour averages of the factors needed to calculate optimum exponents. Nonlinear inversion determines both the exponents and linear prediction filters of short data segments. The averages of all exponents are taken as optimum exponents and for V, N, B⊥, and sin(θc/2) are [1.92, 0.10, 0.79, 3.67] with errors in the second decimal. Hourly values from 1966 to 2014 are used next to calculate the optimum function (opn) and the functions VBs (eys), epsilon (eps), and universal coupling function (ucf). A yearlong window is advanced by 27 days calculating linear prediction filters for the four functions. The functions eps, eys, ucf, and opn, respectively, predict 43.7, 61.2, 65.6, and 68.3% of AL variance. The opn function is 2.74% better than ucf with a confidence interval 2.60-2.86%. Coupling strength defined as the sum of filter weights (nT/mV/m) is virtually identical for all functions and varies systematically with the solar cycle being strongest (188 nT/mV/m) at solar minimum and weakest (104) at solar maximum. Saturation of the polar cap potential approaching solar maximum may explain the variation.
Optimum threshold selection method of centroid computation for Gaussian spot
NASA Astrophysics Data System (ADS)
Li, Xuxu; Li, Xinyang; Wang, Caixia
2015-10-01
Centroid computation of Gaussian spot is often conducted to get the exact position of a target or to measure wave-front slopes in the fields of target tracking and wave-front sensing. Center of Gravity (CoG) is the most traditional method of centroid computation, known as its low algorithmic complexity. However both electronic noise from the detector and photonic noise from the environment reduces its accuracy. In order to improve the accuracy, thresholding is unavoidable before centroid computation, and optimum threshold need to be selected. In this paper, the model of Gaussian spot is established to analyze the performance of optimum threshold under different Signal-to-Noise Ratio (SNR) conditions. Besides, two optimum threshold selection methods are introduced: TmCoG (using m % of the maximum intensity of spot as threshold), and TkCoG ( usingμn +κσ n as the threshold), μn and σn are the mean value and deviation of back noise. Firstly, their impact on the detection error under various SNR conditions is simulated respectively to find the way to decide the value of k or m. Then, a comparison between them is made. According to the simulation result, TmCoG is superior over TkCoG for the accuracy of selected threshold, and detection error is also lower.
Rocket rendezvous at preassigned destinations with optimum entry trajectories
NASA Astrophysics Data System (ADS)
Nangia, A. K.
Optimum entry rendezvous trajectories of commuter rockets between initial noncoaxial coplanar elliptic orbits and destination orbits in an inverse square gravitational field have been determined. Results are presented for an optimum entry rendezvous between earth and Mars. For a given interception angle, the results show that the launch angle for optimum entry rendezvous is smaller than that for the optimum exit rendezvous.
OPTIMUM PLASMA STATES FOR NEXT STEP TOKAMAKS
LIN-LIU,YR; STAMBAUGH,RD
2002-11-01
OAK A271 OPTIMUM PLASMA STATES FOR NEXT STEP TOKAMAKS. The dependence of the ideal ballooning {beta} limit on aspect ratio, A, and elongation {kappa} is systematically explored for nearly 100% bootstrap current driven tokamak equilibria in a wide range of the shape parameters (A = 1.2-7.0, {kappa} = 1.5-6.0 with triangularity {delta} = 0.5). The critical {beta}{sub N} is shown to be optimal at {kappa} = 3.0-4.0 for all A studied and increases as A decreases with a dependence close to A{sup -0.5}. The results obtained can be used as a theoretical basis for the choice of optimum aspect ratio and elongation of next step burning plasma tokamaks or tokamak reactors.
An approach to optimum subsonic inlet design
NASA Technical Reports Server (NTRS)
Luidens, R. W.; Stockman, N. O.; Diedrich, J. H.
1978-01-01
Inlet operating requirements are compared with estimated inlet separation characteristics to identify the most critical inlet operating condition. This critical condition is taken to be the design point and is defined by the values of inlet mass flow, free-stream velocity and inlet angle of attack. Optimum flow distributions on the inlet surface were determined to be a high, flat top Mach number distribution on the inlet lip to turn the flow quickly into the inlet and a flat bottom skin-friction distribution on the diffuser wall to diffuse the flow rapidly and efficiently to the velocity required at the fan face. These optimum distributions are then modified to achieve other desirable flow characteristics. Example applications are given.
An approach to optimum subsonic inlet design
NASA Technical Reports Server (NTRS)
Luidens, R. W.; Stockman, N. O.; Diedrich, J. H.
1979-01-01
The approach consists of comparing inlet operating requirements with estimated inlet separation characteristics to identify the most critical inlet operating condition. This critical condition is taken to be the design point and is defined by the values of inlet mass flow, free stream velocity, and inlet angle of attack. Optimum flow distributions on the inlet surface are determined to be a high, flat top Mach number distribution on the inlet lip to turn the flow quickly into the inlet and a low, flat bottom skin friction distribution on the diffuser wall to diffuse the flow rapidly and efficiently to the velocity required at the fan face. These optimum distributions are then modified to achieve other desirable flow characteristics. Example applications are given. Extension of the method is suggested.
Partially redundant apertures for infrared stellar imaging
NASA Astrophysics Data System (ADS)
Aitken, G. J. M.; Corteggiani, J. P.; Gay, J.
1981-06-01
Spectral-bandwidth constraints to ensure controlled amounts of redundancy are established for a class of two-dimensional partially redundant arrays (PRA's). In the IR, where speckle statistics are poor, the telescope-atmosphere modulation transfer function is determined solely by the PRA geometry. Signal-to-noise-ratio estimates, an optimum aperture criterion, and a six-element PRA example are presented.
Boolean computation of optimum hitting sets
Hulme, B.L.; Baca, L.S.; Shiver, A.W.; Worrell, R.B.
1984-04-01
This report presents the results of computational experience in solving weighted hitting set problems by Boolean algebraic methods. The feasible solutions are obtained by Boolean formula manipulations, and the optimum solutions are obtained by comparing the weight sums of the feasible solutions. Both the algebra and the optimization can be accomplished using the SETS language. One application is to physical protection problems. 8 references, 2 tables.
Active magnetic bearings for optimum turbomachinery design
NASA Technical Reports Server (NTRS)
Hustak, J.; Kirk, R. G.; Schoeneck, K. A.
1985-01-01
The design and shop test results are given for a high speed eight stage centrifugal compressor supported by active magnetic bearings. A brief summary of the rotor dynamics analysis is presented with specific attention given to design considerations for optimum rotor stability. The concerns for retrofit of magnetic bearings in existing machinery are discussed with supporting analysis of a four stage centrifugal compressor. Recommendations are given on design and analysis requirements for successful machinery operation of either retrofit or new design turbomachinery.
Constrained optimum trajectories with specified range
NASA Technical Reports Server (NTRS)
Erzberger, H.; Lee, H.
1980-01-01
The characteristics of optimum fixed-range trajectories whose structure is constrained to climb, steady cruise, and descent segments are derived by application of optimal control theory. The performance function consists of the sum of fuel and time costs, referred to as direct operating costs (DOC). The state variable is range-to-go and the independent variable is energy. In this formulation a cruise segment always occurs at the optimum cruise energy for sufficiently large range. At short ranges (500 n. mi. and less) a cruise segment may also occur below the optimum cruise energy. The existence of such a cruise segment depends primarily on the fuel flow vs thrust characteristics and on thrust constraints. If thrust is a free control variable along with airspeed, it is shown that such cruise segments will not generally occur. If thrust is constrained to some maximum value in climb and to some minimum in descent, such cruise segments generally will occur. The performance difference between free thrust and constrained thrust trajectories has been determined in computer calculations for an example transport aircraft.
Order Theoretical Semantic Recommendation
Joslyn, Cliff A.; Hogan, Emilie A.; Paulson, Patrick R.; Peterson, Elena S.; Stephan, Eric G.; Thomas, Dennis G.
2013-07-23
Mathematical concepts of order and ordering relations play multiple roles in semantic technologies. Discrete totally ordered data characterize both input streams and top-k rank-ordered recommendations and query output, while temporal attributes establish numerical total orders, either over time points or in the more complex case of startend temporal intervals. But also of note are the fully partially ordered data, including both lattices and non-lattices, which actually dominate the semantic strcuture of ontological systems. Scalar semantic similarities over partially-ordered semantic data are traditionally used to return rank-ordered recommendations, but these require complementation with true metrics available over partially ordered sets. In this paper we report on our work in the foundations of partial order measurement in ontologies, with application to top-k semantic recommendation in workflows.
Optimum rocket propulsion for energy-limited transfer
NASA Technical Reports Server (NTRS)
Zuppero, Anthony; Landis, Geoffrey A.
1991-01-01
In order to effect large-scale return of extraterrestrial resources to Earth orbit, it is desirable to optimize the propulsion system to maximize the mass of payload returned per unit energy expended. This optimization problem is different from the conventional rocket propulsion optimization. A rocket propulsion system consists of an energy source plus reaction mass. In a conventional chemical rocket, the energy source and the reaction mass are the same. For the transportation system required, however, the best system performance is achieved if the reaction mass used is from a locally available source. In general, the energy source and the reaction mass will be separate. One such rocket system is the nuclear thermal rocket, in which the energy source is a reactor and the reaction mass a fluid which is heated by the reactor and exhausted. Another energy-limited rocket system is the hydrogen/oxygen rocket where H2/O2 fuel is produced by electrolysis of water using a solar array or a nuclear reactor. The problem is to choose the optimum specific impulse (or equivalently exhaust velocity) to minimize the amount of energy required to produce a given mission delta-v in the payload. The somewhat surprising result is that the optimum specific impulse is not the maximum possible value, but is proportional to the mission delta-v. In general terms, at the beginning of the mission it is optimum to use a very low specific impulse and expend a lot of reaction mass, since this is the most energy efficient way to transfer momentum. However, as the mission progresses, it becomes important to minimize the amount of reaction mass expelled, since energy is wasted moving the reaction mass. Thus, the optimum specific impulse will increase with the mission delta-v. Optimum I(sub sp) is derived for maximum payload return per energy expended for both the case of fixed and variable I(sub sp) engines. Sample missions analyzed include return of water payloads from the moons of Mars and of
Sensitivity of optimum solutions to problem parameters
NASA Technical Reports Server (NTRS)
Sobieszczanski-Sobieski, J.; Barthelemy, J. F.; Ryan, K. M.
1981-01-01
Derivation of the sensitivity equations that yield the sensitivity derivatives directly, which avoids the costly and inaccurate perturb-and-reoptimize approach, is discussed and solvability of the equations is examined. The equations apply to optimum solutions obtained by direct search methods as well as those generated by procedures of the sequential unconstrained minimization technique class. Applications are discussed for the use of the sensitivity derivatives in extrapolation of the optimal objective function and design variable values for incremented parameters, optimization with multiple objectives, and decomposition of large optimization problems.
Optimum interface properties for metal matrix composites
NASA Technical Reports Server (NTRS)
Ghosn, Louis J.; Lerch, Bradley A.
1989-01-01
Due to the thermal expansion coefficient mismatch (CTE) between the fiber and the matrix, high residual sresses exist in metal matrix composite systems upon cool down from processing temperature to room temperature. An interface material can be placed between the fiber and the matrix to reduce the high tensile residual stresses in the matrix. A computer program was written to minimize the residual stress in the matrix subject to the interface material properties. The decision variables are the interface modulus, thickness and thermal expansion coefficient. The properties of the interface material are optimized such that the average distortion energy in the matrix and the interface is minimized. As a result, the only active variable is the thermal expansion coefficient. The optimum modulus of the interface is always the minimum allowable value and the interface thickness is always the maximum allowable value, independent of the fiber/matrix system. The optimum interface thermal expansion coefficient is always between the values of the fiber and the matrix. Using this analysis, a survey of materials was conducted for use as fiber coatings in some specific composite systems.
Scale effect and optimum relations for sea surface planning
NASA Technical Reports Server (NTRS)
Sedov, L.
1947-01-01
From the general dimensional and mechanical similarity theory it follows that a condition of steady motion of a given shape\\bottom with constant speed on the surface of water is determined by four nondimensional parameters. By considering the various systems of independent parameters which are applied in theory and practice and special tests, there is determined their mutual relations and their suitability as planning characteristics. In studying the scale effect on the basis of the Prnndtl formula for the friction coefficient for a turbulent condition the order of magnitude is given of the error in applying the model data to full scale in the case of a single-step bottom For a bottom of complicated shape it is shown how from the test data of the hydrodynamic characteristics for one speed with various loads, or one load with various speeds, there may be obtained by simple computation with good approximation the hydrodynamic characteristics for a different speed or for a different load. (These considerations may be of use in solving certain problems on the stability of planning.) This permits extrapolating the curve of resistance against speed for large speeds inaccessible in the tank tests or for other loads which were not tested. The data obtained by computation are in good agreement with the test results. Problems regarding the optimum trim angle or the optimum width in the case of planning of a flat plate are considered from the point of view of the minimum resistance for a given load on the water and planning speeds. Formulas and graphs are given for the optimum value of the planning coefficient and the corresponding values of the trim angle and width of the flat plate.
Design optimum frac jobs using virtual intelligence techniques
NASA Astrophysics Data System (ADS)
Mohaghegh, Shahab; Popa, Andrei; Ameri, Sam
2000-10-01
Designing optimal frac jobs is a complex and time-consuming process. It usually involves the use of a two- or three-dimensional computer model. For the computer models to perform as intended, a wealth of input data is required. The input data includes wellbore configuration and reservoir characteristics such as porosity, permeability, stress and thickness profiles of the pay layers as well as the overburden layers. Among other essential information required for the design process is fracturing fluid type and volume, proppant type and volume, injection rate, proppant concentration and frac job schedule. Some of the parameters such as fluid and proppant types have discrete possible choices. Other parameters such as fluid and proppant volume, on the other hand, assume values from within a range of minimum and maximum values. A potential frac design for a particular pay zone is a combination of all of these parameters. Finding the optimum combination is not a trivial process. It usually requires an experienced engineer and a considerable amount of time to tune the parameters in order to achieve desirable outcome. This paper introduces a new methodology that integrates two virtual intelligence techniques, namely, artificial neural networks and genetic algorithms to automate and simplify the optimum frac job design process. This methodology requires little input from the engineer beyond the reservoir characterizations and wellbore configuration. The software tool that has been developed based on this methodology uses the reservoir characteristics and an optimization criteria indicated by the engineer, for example a certain propped frac length, and provides the detail of the optimum frac design that will result in the specified criteria. An ensemble of neural networks is trained to mimic the two- or three-dimensional frac simulator. Once successfully trained, these networks are capable of providing instantaneous results in response to any set of input parameters. These
Carbon sequestration, optimum forest rotation and their environmental impact
Kula, Erhun; Gunalay, Yavuz
2012-11-15
Due to their large biomass forests assume an important role in the global carbon cycle by moderating the greenhouse effect of atmospheric pollution. The Kyoto Protocol recognises this contribution by allocating carbon credits to countries which are able to create new forest areas. Sequestrated carbon provides an environmental benefit thus must be taken into account in cost-benefit analysis of afforestation projects. Furthermore, like timber output carbon credits are now tradable assets in the carbon exchange. By using British data, this paper looks at the issue of identifying optimum felling age by considering carbon sequestration benefits simultaneously with timber yields. The results of this analysis show that the inclusion of carbon benefits prolongs the optimum cutting age by requiring trees to stand longer in order to soak up more CO{sub 2}. Consequently this finding must be considered in any carbon accounting calculations. - Highlights: Black-Right-Pointing-Pointer Carbon sequestration in forestry is an environmental benefit. Black-Right-Pointing-Pointer It moderates the problem of global warming. Black-Right-Pointing-Pointer It prolongs the gestation period in harvesting. Black-Right-Pointing-Pointer This paper uses British data in less favoured districts for growing Sitka spruce species.
Determination of optimum oven cooking procedures for lean beef products.
Rodas-González, Argenis; Larsen, Ivy L; Uttaro, Bethany; Juárez, Manuel; Parslow, Joyce; Aalhus, Jennifer L
2015-11-01
In order to determine optimum oven cooking procedures for lean beef, the effects of searing at 232 or 260°C for 0, 10, 20 or 30 min, and roasting at 160 or 135°C on semimembranosus (SM) and longissimus lumborum (LL) muscles were evaluated. In addition, the optimum determined cooking method (oven-seared for 10 min at 232°C and roasted at 135°C) was applied to SM roasts varying in weight from 0.5 to 2.5 kg. Mainly, SM muscles seared for 0 or 10 min at 232°C followed by roast at 135°C had lower cooking loss, higher external browning color, more uniform internal color, and were more tender and flavorful (P < 0.05). Roast weights ≥1 kg had lesser cooking loss, more uniform internal color and tender compared to 0.5 kg (P < 0.05). Consequently, roasting at low temperature without searing is the recommended oven cooking procedure; with best response from muscle roast weight ≥1 kg. PMID:26788289
Optimum design of geodesically stiffened composite plates
NASA Technical Reports Server (NTRS)
Guerdal, Zafer; Phillips, John L.
1988-01-01
With the goal of tailorability in mind, the in-plane stiffness characteristics of a particular grid stiffened plate configuration under axial and shear loads have been studied. The contribution of the skin to the stiffener network and the resultant skin/rib interaction is analyzed. For the given plate geometry and loads, it is shown that an optimum configuration does exist. To achieve optimally designed practical plate configurations, buckling constraints need to be included in the design. Due to the complex geometry and loading of the plates, a simplified local buckling analysis of isolated stiffeners and triangular skin elements between the stiffeners is considered. Development of a stiffener buckling analysis represent stiffeners as shear deformable plate elements is presented.
Optimum runway orientation relative to crosswinds
NASA Technical Reports Server (NTRS)
Falls, L. W.; Brown, S. C.
1972-01-01
Specific magnitudes of crosswinds may exist that could be constraints to the success of an aircraft mission such as the landing of the proposed space shuttle. A method is required to determine the orientation or azimuth of the proposed runway which will minimize the probability of certain critical crosswinds. Two procedures for obtaining the optimum runway orientation relative to minimizing a specified crosswind speed are described and illustrated with examples. The empirical procedure requires only hand calculations on an ordinary wind rose. The theoretical method utilizes wind statistics computed after the bivariate normal elliptical distribution is applied to a data sample of component winds. This method requires only the assumption that the wind components are bivariate normally distributed. This assumption seems to be reasonable. Studies are currently in progress for testing wind components for bivariate normality for various stations. The close agreement between the theoretical and empirical results for the example chosen substantiates the bivariate normal assumption.
Optimum design of ninety degree bends
NASA Technical Reports Server (NTRS)
Modi, Vijay; Cabuk, Hayri; Huan, Jian-Chun; Quadracci, Richard
1992-01-01
An algorithm for the optimum design of an internal flow component to obtain the maximum pressure rise is presented. Maximum pressure rise in a duct with simultaneous turning and diffusion is shown to be related to the control of flow separation on the passage walls. Such a flow is usually associated with downstream conditions that are desirable in turbomachinery and propulsion applications to ensure low loss and stable performance. The algorithm requires the solution of an 'adjoint' problem in addition to the 'direct' equations governing the flow in a body, which in the present analysis are assumed to be the laminar Navier-Stokes equations. The theoretical framework and computational algorithms presented in this study are for the steady Navier-Stokes equations. A procedure is developed for the numerical solution of the adjoint equations. This procedure is coupled with a direct solver in a design iteration loop, that provides a new shape with a higher pressure rise. This procedure is first validated for the design of optimum plane diffusers in two-dimensional flow. The direct Navier-Stokes and the 'adjoint' equations are solved using a finite volume formulation for spatial discretization in an artificial compressibility framework. A simplified version of the above approach is then utilized to design ninety degree diffusing bends. Calculations were carried out for a mean radius ratio at inlet of 2.5 and Reynolds numbers varying from 100 to 500. While at this stage laminar flows is assumed, it is shown that a similar approach can be conceived for turbulent flows.
Optimum Integrated Heterodyne Photoreceiver for Coherent Lidar Applications
NASA Technical Reports Server (NTRS)
Amzajerdian, Farzin; Pierrottet, Diego; Singh, Upendra; Kavaya, Michael
2005-01-01
Many coherent lidar applications, particularly airborne and space-based applications, impose stringent power and size constraints while requiring high levels of sensitivity. For this reason, optimization of the lidar heterodyne photoreceiver is one of the critical steps in ensuring full utilization of limited resources to achieve the required sensitivity. The analysis of 2-micron heterodyne receivers shows that substantial improvement of the order of 3 dB can be obtained by proper optimization of the receiver key control parameters and elimination of its parasitic capacitances by integrating the detector, its bias circuit, and the preamplifier on a single substrate. This paper describes analytical steps for defining optimum heterodyne receiver design parameters and development of experimental devices operating at 2-micron wavelength.
Optimum Actuator Selection with a Genetic Algorithm for Aircraft Control
NASA Technical Reports Server (NTRS)
Rogers, James L.
2004-01-01
The placement of actuators on a wing determines the control effectiveness of the airplane. One approach to placement maximizes the moments about the pitch, roll, and yaw axes, while minimizing the coupling. For example, the desired actuators produce a pure roll moment without at the same time causing much pitch or yaw. For a typical wing, there is a large set of candidate locations for placing actuators, resulting in a substantially larger number of combinations to examine in order to find an optimum placement satisfying the mission requirements and mission constraints. A genetic algorithm has been developed for finding the best placement for four actuators to produce an uncoupled pitch moment. The genetic algorithm has been extended to find the minimum number of actuators required to provide uncoupled pitch, roll, and yaw control. A simplified, untapered, unswept wing is the model for each application.
Improve filtration for optimum equipment reliability
Cervera, S.M.
1996-01-01
The introduction 20 years ago of the American Petroleum Institute Standard API-614 as a purchase specification for lubrication, shaft sealing and control oil systems, had a considerable impact and did much to improve system reliability at that time. Today, however, these recommendations regarding filter rating and flushing cleanliness are outdated. Much research in the tribology field correlates clearance size particulate contamination with accelerated component wear, fatigue and performance degradation. Some of these studies demonstrate that by decreasing the population of clearance size particulate in lubrication oils, component life increases exponentially. Knowing the dynamic clearances of a piece of machinery makes it possible, using the ISO 4406 Cleanliness Code, to determine what cleanliness level will minimize contamination-related component wear/fatigue and thus help optimize machinery performance and reliability. Data obtained by the author through random sampling of rotating equipment lube and seal oil systems indicate that the API-614 standard, as it pertains to filtration and flushing, is insufficient to ensure that particulate contamination is maintained to within the levels necessary to achieve optimum equipment reliability and safety, without increasing operating cost. Adopting and practicing the guidelines presented should result in the following benefits: (1) the frequency of bearing, oil pump, mechanical seal, fluid coupling, gearbox and hydraulic control valve failures would be minimized; (2) the mean time between planned maintenance (MTBPM) would be increased. The result will be a substantial increase in safety and cost savings to the operator.
Designing from minimum to optimum functionality
NASA Astrophysics Data System (ADS)
Bannova, Olga; Bell, Larry
2011-04-01
This paper discusses a multifaceted strategy to link NASA Minimal Functionality Habitable Element (MFHE) requirements to a compatible growth plan; leading forward to evolutionary, deployable habitats including outpost development stages. The discussion begins by reviewing fundamental geometric features inherent in small scale, vertical and horizontal, pressurized module configuration options to characterize applicability to meet stringent MFHE constraints. A proposed scenario to incorporate a vertical core MFHE concept into an expanded architecture to provide continuity of structural form and a logical path from "minimum" to "optimum" design of a habitable module. The paper describes how habitation and logistics accommodations could be pre-integrated into a common Hab/Log Module that serves both habitation and logistics functions. This is offered as a means to reduce unnecessary redundant development costs and to avoid EVA-intensive on-site adaptation and retrofitting requirements for augmented crew capacity. An evolutionary version of the hard shell Hab/Log design would have an expandable middle section to afford larger living and working accommodations. In conclusion, the paper illustrates that a number of cargo missions referenced for NASA's 4.0.0 Lunar Campaign Scenario could be eliminated altogether to expedite progress and reduce budgets. The plan concludes with a vertical growth geometry that provides versatile and efficient site development opportunities using a combination of hard Hab/Log modules and a hybrid expandable "CLAM" (Crew Lunar Accommodations Module) element.
Optimum nutrition: thiamin, biotin and pantothenate.
Bender, D A
1999-05-01
The metabolism of glucose is deranged in thiamin deficiency, but once any deficiency has been corrected there is no further effect of increased thiamin intake on the ability to metabolize glucose through either pyruvate dehydrogenase (EC 1.2.4.1) and the citric acid cycle, or the pentose phosphate pathway, in which transketolase (EC 2.2.1.1) is the thiamin-dependent step. It has been suggested that the Wernicke-Korsakoff syndrome is associated with a genetic variant of transketolase which requires a higher than normal concentration of thiamin diphosphate for activity. This finding would suggest that there may be a group of the population who have a higher than average requirement for thiamin, but the evidence is not convincing. There are no estimates of biotin requirements, but either coenzyme saturation of erythrocyte pyruvate carboxylase, or the excretion of 3-hydroxy-isovalerate (perhaps after a test dose of leucine) could be used to assess requirements in depletion-repletion studies. Biotin deficiency leads to impaired glucose tolerance, but it is unlikely that glucose tolerance could be used to assess optimum biotin status, since other more common factors affect glucose tolerance to a greater extent. Plasma triacylglycerol and nonesterified fatty acids are moderately elevated in pantothenic acid deficiency. However, this is unlikely to be useful in assessing pantothenate status, since again, other more common factors affect plasma lipids. To date there are no biochemical indices of adequate pantothenate nutrition, and no estimates of requirements. PMID:10466187
Optimum deposition conditions of ultrasmooth silver nanolayers
2014-01-01
Reduction of surface plasmon-polariton losses due to their scattering on metal surface roughness still remains a challenge in the fabrication of plasmonic devices for nanooptics. To achieve smooth silver films, we study the dependence of surface roughness on the evaporation temperature in a physical vapor deposition process. At the deposition temperature range 90 to 500 K, the mismatch of thermal expansion coefficients of Ag, Ge wetting layer, and sapphire substrate does not deteriorate the metal surface. To avoid ice crystal formation on substrates, the working temperature of the whole physical vapor deposition process should exceed that of the sublimation at the evaporation pressure range. At optimum room temperature, the root-mean-square (RMS) surface roughness was successfully reduced to 0.2 nm for a 10-nm Ag layer on sapphire substrate with a 1-nm germanium wetting interlayer. Silver layers of 10- and 30-nm thickness were examined using an atomic force microscope (AFM), X-ray reflectometry (XRR), and two-dimensional X-ray diffraction (XRD2). PACS 63.22.Np Layered systems; 68. Surfaces and interfaces; thin films and nanosystems (structure and nonelectronic properties); 81.07.-b Nanoscale materials and structures: fabrication and characterization PMID:24685115
Optimum harvest maturity for Leymus chinensis seed
Lin, Jixiang; Wang, Yingnan; Qi, Mingming; Li, Xiaoyu; Yang, Chunxue; Wang, Yongcui
2016-01-01
ABSTRACT Timely harvest is critical to achieve maximum seed viability and vigour in agricultural production. However, little information exists concerning how to reap the best quality seeds of Leymus chinensis, which is the dominant and most promising grass species in the Songnen Grassland of Northern China. The objective of this study was to investigate and evaluate possible quality indices of the seeds at different days after peak anthesis. Seed quality at different development stages was assessed by the colours of the seed and lemmas, seed weight, moisture content, electrical conductivity of seed leachate and germination indices. Two consecutive years of experimental results showed that the maximum seed quality was recorded at 39 days after peak anthesis. At this date, the colours of the seed and lemmas reached heavy brown and yellow, respectively. The seed weight was highest and the moisture content and the electrical conductivity of seed leachate were lowest. In addition, the seed also reached its maximum germination percentage and energy at this stage, determined using a standard germination test (SGT) and accelerated ageing test (AAT). Thus, Leymus chinensis can be harvested at 39 days after peak anthesis based on the changes in parameters. Colour identification can be used as an additional indicator to provide a more rapid and reliable measure of optimum seed maturity; approximately 10 days after the colour of the lemmas reached yellow and the colour of the seed reached heavy brown, the seed of this species was suitable for harvest. PMID:27170257
Optimum harvest maturity for Leymus chinensis seed.
Lin, Jixiang; Wang, Yingnan; Qi, Mingming; Li, Xiaoyu; Yang, Chunxue; Wang, Yongcui; Mu, Chunsheng
2016-01-01
Timely harvest is critical to achieve maximum seed viability and vigour in agricultural production. However, little information exists concerning how to reap the best quality seeds of Leymus chinensis, which is the dominant and most promising grass species in the Songnen Grassland of Northern China. The objective of this study was to investigate and evaluate possible quality indices of the seeds at different days after peak anthesis. Seed quality at different development stages was assessed by the colours of the seed and lemmas, seed weight, moisture content, electrical conductivity of seed leachate and germination indices. Two consecutive years of experimental results showed that the maximum seed quality was recorded at 39 days after peak anthesis. At this date, the colours of the seed and lemmas reached heavy brown and yellow, respectively. The seed weight was highest and the moisture content and the electrical conductivity of seed leachate were lowest. In addition, the seed also reached its maximum germination percentage and energy at this stage, determined using a standard germination test (SGT) and accelerated ageing test (AAT). Thus, Leymus chinensis can be harvested at 39 days after peak anthesis based on the changes in parameters. Colour identification can be used as an additional indicator to provide a more rapid and reliable measure of optimum seed maturity; approximately 10 days after the colour of the lemmas reached yellow and the colour of the seed reached heavy brown, the seed of this species was suitable for harvest. PMID:27170257
Associative memory - An optimum binary neuron representation
NASA Technical Reports Server (NTRS)
Awwal, A. A.; Karim, M. A.; Liu, H. K.
1989-01-01
Convergence mechanism of vectors in the Hopfield's neural network is studied in terms of both weights (i.e., inner products) and Hamming distance. It is shown that Hamming distance should not always be used in determining the convergence of vectors. Instead, weights (which in turn depend on the neuron representation) are found to play a more dominant role in the convergence mechanism. Consequently, a new binary neuron representation for associative memory is proposed. With the new neuron representation, the associative memory responds unambiguously to the partial input in retrieving the stored information.
Concomitant Ordering and Symmetry Lowering
ERIC Educational Resources Information Center
Boo, William O. J.; Mattern, Daniell L.
2008-01-01
Examples of concomitant ordering include magnetic ordering, Jahn-Teller cooperative ordering, electronic ordering, ionic ordering, and ordering of partially-filled sites. Concomitant ordering sets in when a crystal is cooled and always lowers the degree of symmetry of the crystal. Concomitant ordering concepts can also be productively applied to…
Implementation of optimum solar electricity generating system
NASA Astrophysics Data System (ADS)
Singh, Balbir Singh Mahinder; Sivapalan, Subarna; Najib, Nurul Syafiqah Mohd; Menon, Pradeep; Karim, Samsul Ariffin A.
2014-10-01
Under the 10th Malaysian Plan, the government is expecting the renewable energy to contribute approximately 5.5% to the total electricity generation by the year 2015, which amounts to 98MW. One of the initiatives to ensure that the target is achievable was to establish the Sustainable Energy Development Authority of Malaysia. SEDA is given the authority to administer and manage the implementation of the feed-in tariff (FiT) mechanism which is mandated under the Renewable Energy Act 2011. The move to establish SEDA is commendable and the FiT seems to be attractive but there is a need to create awareness on the implementation of the solar electricity generating system (SEGS). In Malaysia, harnessing technologies related to solar energy resources have great potential for implementation. However, the main issue that plagues the implementation of SEGS is the intermittent nature of this source of energy. The availability of sunlight is during the day time, and there is a need for electrical energy storage system, so that there is electricity available during the night time as well. The meteorological condition such as clouds, haze and pollution affects the SEGS as well. The PV based SEGS is seems to be promising electricity generating system that can contribute towards achieving the 5.5% target and will be able to minimize the negative effects of utilizing fossil fuels for electricity generation on the environment. Malaysia is committed to Kyoto Protocol, which emphasizes on fighting global warming by achieving stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. In this paper, the technical aspects of the implementation of optimum SEGS is discussed, especially pertaining to the positioning of the PV panels.
Implementation of optimum solar electricity generating system
Singh, Balbir Singh Mahinder Karim, Samsul Ariffin A.; Sivapalan, Subarna; Najib, Nurul Syafiqah Mohd; Menon, Pradeep
2014-10-24
Under the 10{sup th} Malaysian Plan, the government is expecting the renewable energy to contribute approximately 5.5% to the total electricity generation by the year 2015, which amounts to 98MW. One of the initiatives to ensure that the target is achievable was to establish the Sustainable Energy Development Authority of Malaysia. SEDA is given the authority to administer and manage the implementation of the feed-in tariff (FiT) mechanism which is mandated under the Renewable Energy Act 2011. The move to establish SEDA is commendable and the FiT seems to be attractive but there is a need to create awareness on the implementation of the solar electricity generating system (SEGS). In Malaysia, harnessing technologies related to solar energy resources have great potential for implementation. However, the main issue that plagues the implementation of SEGS is the intermittent nature of this source of energy. The availability of sunlight is during the day time, and there is a need for electrical energy storage system, so that there is electricity available during the night time as well. The meteorological condition such as clouds, haze and pollution affects the SEGS as well. The PV based SEGS is seems to be promising electricity generating system that can contribute towards achieving the 5.5% target and will be able to minimize the negative effects of utilizing fossil fuels for electricity generation on the environment. Malaysia is committed to Kyoto Protocol, which emphasizes on fighting global warming by achieving stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. In this paper, the technical aspects of the implementation of optimum SEGS is discussed, especially pertaining to the positioning of the PV panels.
Optimum wavelengths for two color ranging
NASA Technical Reports Server (NTRS)
Degnan, John J.
1993-01-01
The range uncertainties associated with the refractive atmosphere can be mitigated by the technique of two color, or dual wavelength, ranging. The precision of the differential time of flight (DTOF) measurement depends on the atmospheric dispersion between the two wavelengths, the received pulsewidths and photoelectron counts, and on the amount of temporal averaging. In general, the transmitted wavelengths are not independently chosen but instead are generated via nonlinear optics techniques (harmonic crystals, Raman scattering, etc.) which also determine their relative pulsewidths. The mean received photoelectrons at each wavelength are calculated via the familiar radar link equation which contains several wavelength dependent parameters. By collecting the various wavelength dependent terms, one can define a wavelength figure of merit for a two color laser ranging system. In this paper, we apply the wavelength figure of merit to the case of an extremely clear atmosphere and draw several conclusions regarding the relative merits of fundamental-second harmonic, fundamental-third harmonic, second-third harmonic, and Raman two color systems. We find that, in spite of the larger dispersion between wavelengths, fundamental-third harmonic systems have the lowest figure of merit due to a combination of poor detector performance at the fundamental and poor atmospheric transmission at the third harmonic. The fundamental-second harmonic systems (approximately 700 nm and 350 nm) have the highest figure of merit, but second-third harmonic systems, using fundamental transmitters near 1000 nm, are a close second. Raman-shifted transmitters appear to offer no advantage over harmonic systems because of the relatively small wavelength separation that can be achieved in light gases such as hydrogen and the lack of good ultrashort pulse transmitters with an optimum fundamental wavelength near 400 nm.
The screening effects of carbon nanotube arrays and its field emission optimum density
Cai, Dan Liu, Lie
2013-12-15
In order to investigate the field emission optimum density of carbon nanotube (CNT) array, the screening effects of CNT array have been studied. It has been shown that the electric field in the vicinity of an individual nanotube of array can be notable distorted due to the screening action of the surrounding neighbors. The optimum normalized spacing s/l(as referred to the length) for the maximum emission current is inversely proportional to aspect ratio l/r and electric field strength for CNT arrays with a fixed dimension.
Optimum target source term estimation for high energy electron accelerators
NASA Astrophysics Data System (ADS)
Nayak, M. K.; Sahu, T. K.; Nair, Haridas G.; Nandedkar, R. V.; Bandyopadhyay, Tapas; Tripathi, R. M.; Hannurkar, P. R.
2016-05-01
Optimum target for bremsstrahlung emission is defined as the thickness of the target material, which produces maximum bremsstrahlung yield, on interaction of electron with the target. The bremsstrahlung dose rate per unit electron beam power at a distance of 1 m from the target material gives the optimum target source term. In the present work, simulations were performed for three different electron energies, 450, 1000 and 2500 MeV using EGSnrc Monte-Carlo code to determine the optimum thickness. An empirical relation for optimum target as a function of electron energy and atomic number of the target materials is found out from results. Using the simulated optimum target thickness, experiments are conducted to determine the optimum target source term. For the experimental determination, two available electron energies, 450 MeV and 550 MeV from booster synchrotron of Indus facility is used. The optimum target source term for these two energies are also simulated. The experimental and simulated source term are found to be in very good agreement within ±3%. Based on the agreement of the simulated source term with the experimental source term at 450 MeV and 550 MeV, the same simulation methodology is used to simulate optimum target source term up to 2500 MeV. The paper describes the simulations and experiments carried out on optimum target bremsstrahlung source term and the results obtained.
Optimum shape of a blunt forebody in hypersonic flow
NASA Technical Reports Server (NTRS)
Maestrello, L.; Ting, L.
1989-01-01
The optimum shape of a blunt forebody attached to a symmetric wedge or cone is determined. The length of the forebody, its semi-thickness or base radius, the nose radius and the radius of the fillet joining the forebody to the wedge or cone are specified. The optimum shape is composed of simple curves. Thus experimental models can be built readily to investigate the utilization of aerodynamic heating for boundary layer control. The optimum shape based on the modified Newtonian theory can also serve as the preliminary shape for the numerical solution of the optimum shape using the governing equations for a compressible inviscid or viscous flow.
ERIC Educational Resources Information Center
Katayama, Andrew D.; Crooks, Steven M.; Weiler, William
The effectiveness of notes provided students in two formats was studied. Students received either a completed set of notes or a partially completed set, with approximately half the information left blank. The study was also designed to investigate the effect of test taking conditions, whether immediate (shortly after the study session) or delayed…
Determining optimum climate drivers for weather risk projections
NASA Astrophysics Data System (ADS)
Chavez, Erik; Kilian, Markus; Lucarini, Valerio
2016-04-01
In spite of the exponential increase of available data, the uncertainties of projections of weather variability, especially at local scale, have not decreased. This poses important challenges for the design of weather risk management strategies in various vulnerable sectors such as energy or agricultural production. This paper focuses on a two step methodology to enable projection of local weather risk in future climate scenarios. First, we focus on the optimum selection of drivers of regional weather patterns in order to project local weather variability risk estimates in future climate scenarios. This is carried out through the use of stochastic downscaling enabling conditional modelling of pixel-level distributions of weather variables as a function of inter-annual and inter-decadal climate variability drivers. Secondly, a statistical and physically-based climate model selection methodology is developed in order to produce a sub-ensemble of inter-annual and decadal variability drivers dataset that allows accurate and robust projection of weather variability. The case study of South Eastern Africa will be used. Datasets retrieved from CMIP5 repository in three RCP scenarios (historical, 8.5 and 2.5) are used as well as observed historical weather data.
NASA Astrophysics Data System (ADS)
Castillo, Henry A., Jr.
1992-06-01
The objective of this research is to create a flexible code which is to be used in the investigation of optimum (minimum weight) shell designs. A shell analysis/design program, DAPS3, and a general purpose numerical optimization program, ADS, are incorporated into a single code, THESIS. This code provides the user great flexibility in changing the design variables and constraints which model the optimization problem. The optimum designs produced by this code are compared to DAPS3 optimum designs in order to identify any improvements made by the numerical optimization technique.
50 CFR 600.310 - National Standard 1-Optimum Yield.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false National Standard 1-Optimum Yield. 600.310 Section 600.310 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MAGNUSON-STEVENS ACT PROVISIONS National Standards § 600.310 National Standard 1—Optimum Yield....
50 CFR 600.310 - National Standard 1-Optimum Yield.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false National Standard 1-Optimum Yield. 600.310 Section 600.310 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MAGNUSON-STEVENS ACT PROVISIONS National Standards § 600.310 National Standard 1—Optimum Yield....
50 CFR 600.310 - National Standard 1-Optimum Yield.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 50 Wildlife and Fisheries 12 2012-10-01 2012-10-01 false National Standard 1-Optimum Yield. 600.310 Section 600.310 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MAGNUSON-STEVENS ACT PROVISIONS National Standards § 600.310 National Standard 1—Optimum Yield....
50 CFR 600.310 - National Standard 1-Optimum Yield.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false National Standard 1-Optimum Yield. 600.310 Section 600.310 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MAGNUSON-STEVENS ACT PROVISIONS National Standards § 600.310 National Standard 1—Optimum Yield....
50 CFR 600.310 - National Standard 1-Optimum Yield.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 50 Wildlife and Fisheries 10 2011-10-01 2011-10-01 false National Standard 1-Optimum Yield. 600.310 Section 600.310 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MAGNUSON-STEVENS ACT PROVISIONS National Standards § 600.310 National Standard 1—Optimum Yield....
Optimum spaceborne computer system design by simulation
NASA Technical Reports Server (NTRS)
Williams, T.; Kerner, H.; Weatherbee, J. E.; Taylor, D. S.; Hodges, B.
1973-01-01
A deterministic simulator is described which models the Automatically Reconfigurable Modular Multiprocessor System (ARMMS), a candidate computer system for future manned and unmanned space missions. Its use as a tool to study and determine the minimum computer system configuration necessary to satisfy the on-board computational requirements of a typical mission is presented. The paper describes how the computer system configuration is determined in order to satisfy the data processing demand of the various shuttle booster subsytems. The configuration which is developed as a result of studies with the simulator is optimal with respect to the efficient use of computer system resources.
Fuel optimum low-thrust elliptic transfer using numerical averaging
NASA Astrophysics Data System (ADS)
Tarzi, Zahi; Speyer, Jason; Wirz, Richard
2013-05-01
Low-thrust electric propulsion is increasingly being used for spacecraft missions primarily due to its high propellant efficiency. As a result, a simple and fast method for low-thrust trajectory optimization is of great value for preliminary mission planning. However, few low-thrust trajectory tools are appropriate for preliminary mission design studies. The method presented in this paper provides quick and accurate solutions for a wide range of transfers by using numerical orbital averaging to improve solution convergence and include orbital perturbations. Thus, preliminary trajectories can be obtained for transfers which involve many revolutions about the primary body. This method considers minimum fuel transfers using first-order averaging to obtain the fuel optimum rates of change of the equinoctial orbital elements in terms of each other and the Lagrange multipliers. Constraints on thrust and power, as well as minimum periapsis, are implemented and the equations are averaged numerically using a Gausian quadrature. The use of numerical averaging allows for more complex orbital perturbations to be added in the future without great difficulty. The effects of zonal gravity harmonics, solar radiation pressure, and thrust limitations due to shadowing are included in this study. The solution to a transfer which minimizes the square of the thrust magnitude is used as a preliminary guess for the minimum fuel problem, thus allowing for faster convergence to a wider range of problems. Results from this model are shown to provide a reduction in propellant mass required over previous minimum fuel solutions.
Atlas based kinematic optimum design of the Stewart parallel manipulator
NASA Astrophysics Data System (ADS)
Shao, Zhufeng; Tang, Xiaoqiang; Wang, Liping; Sun, Dengfeng
2015-01-01
Optimum design is a key approach to make full use of potential advantages of a parallel manipulator. The optimum design of multi-parameter parallel manipulators(more than three design parameters), such as Stewart manipulator, relies on analysis based and algorithm based optimum design methods, which fall to be accurate or intuitive. To solve this problem and achieve both accurate and intuition, atlas based optimum design of a general Stewart parallel manipulator is established, with rational selection of design parameters. Based on the defined spherical usable workspace(SUW), primary kinematic performance indices of the Stewart manipulator, involving workspace and condition number are introduced and analyzed. Then, corresponding performance atlases are drawn with the established non-dimensional design space, and impact of joint distribution angles on the manipulator performance is analyzed and illustrated. At last, an example on atlas based optimum design of the Stewart manipulator is accomplished to illustrate the optimum design process, considering the end-effector posture. Deduced atlases can be flexibly applied to both quantitative and qualitative analysis to get the desired optimal design for the Stewart manipulator with respect to related performance requirements. Besides, the established optimum design method can be further applied to other multi-parameter parallel manipulators.
Complete characterization of partially coherent and partially polarized optical fields.
Basso, Gabriel; Oliveira, Luimar; Vidal, Itamar
2014-03-01
We suggest a method to access the second-order, or two-point, Stokes parameters of a partially coherent and partially polarized Gaussian model optical field from an intensity interferometry experiment. Through a remarkably simple experimental arrangement, it is possible to measure the two-point and one-point Stokes parameters simultaneously, allowing the reconstruction of the coherence matrix and the polarization matrix, thus completely characterizing the optical field both statistically and locally on the observation plane. Developments, automation, and applications are pointed out. PMID:24690711
Electrodialysis simulation to achieve optimum current density
NASA Technical Reports Server (NTRS)
Herrmann, Cal C.
1993-01-01
Electrodialysis is used to remove salts from waste or other water streams, to yield a concentrated brine and a substatially deionized product water. During the electrodialysis process, the boundary layer adjacent to the ion selective membrane can become depleted of ions, resulting in severe pH changes sometimes accompanied by precipitation, and power losses, by a process known as water splitting. In order to optimize the applied electric current density, to achieve maximum deionization without exceeding the limiting current at any point along the path, a simulation program has been created to plot ion concentrations and fluxes, and cell current densities and voltages along the electrodialysis path. A means for tapering the current density along the path is recommended.
Optimum conditions for prebiotic evolution in extraterrestrial environments
NASA Astrophysics Data System (ADS)
Abbas, Ousama H.
The overall goal of the dissertation was to devise synthetic pathways leading to the production of peptides and amino acids from smaller organic precursors. To this end, eight different zeolites were tested in order to determine their catalytic potential in the conversion of amino acids to peptides. The zeolites tested were either synthetic or naturally occurring. Acidic solutions of amino acids were prepared with or without zeolites and their reactivity was monitored over a four-week time interval. The kinetics and feasibility of peptide synthesis from selected amino acid combinations was investigated via the paper chromatography technique. Nine different amino acids were tested. The nature and extent of product were measured at constant time intervals. It was found that two ZSM-5 synthetic zeolites as well as the Fisher Scientific zeolite mix without alumina salts may have a catalytic potential in the conversion of amino acids to peptides. The conversion was verified by matching the paper chromatogram of the experimental product with that of a known peptide. The experimental results demonstrate that the optimum solvent system for paper chromatographic analysis of the zeolite-catalyzed self-assembly of the amino acids L-aspartic acid, L- asparagine, L-histidine, and L-serine is a 50:50 mixture of 1-butanol and acetone by volume. For the amino acids L-alanine, L-glycine, and L-valine, the optimum solvent was found to be a 30:70 mixture of ammonia and propanol by volume. A mathematical model describing the distance traveled (spot position) versus reaction time was constructed for the zeolite-catalyzed conversion of L- leucine and L-tyrosine and was found to approximately follow the function f(t) = 25 ln t. Two case studies for prebiotic synthesis leading to the production of amino acids or peptides in extraterrestrial environments were discussed: one involving Saturn's moon Titan, and the other involving Jupiter's moon Europa. In the Titan study, it was determined
Investigation of earthquake factor for optimum tuned mass dampers
NASA Astrophysics Data System (ADS)
Nigdeli, Sinan Melih; Bekdaş, Gebrail
2012-09-01
In this study the optimum parameters of tuned mass dampers (TMD) are investigated under earthquake excitations. An optimization strategy was carried out by using the Harmony Search (HS) algorithm. HS is a metaheuristic method which is inspired from the nature of musical performances. In addition to the HS algorithm, the results of the optimization objective are compared with the results of the other documented method and the corresponding results are eliminated. In that case, the best optimum results are obtained. During the optimization, the optimum TMD parameters were searched for single degree of freedom (SDOF) structure models with different periods. The optimization was done for different earthquakes separately and the results were compared.
Silver catalysts in the partial oxidation of methanol to formaldehyde
Devochkin, A.N.; Pestryakov, A.N.; Kurina, L.N.; Sakharov, A.A.
1992-07-20
A comparative study of the catalytic activity of supported (Ag/pumice, LNKh-M) and bulk (Ag{sub cryst}, SD, KS) catalysts for methanol oxidation was carried out. The effect of technological parameters on the partial oxidation of methanol was studied. The optimum conditions for conducting the process on the catalysts studied were determined. 5 refs., 1 tab.
NASA Astrophysics Data System (ADS)
Li, Chunxiang; Zhu, Bilei
2006-11-01
The double tuned mass dampers (DTMD), consisting of one larger mass block (i.e. one larger tuned mass damper (TMD)) and one smaller mass block (i.e. one smaller TMD), have been proposed to seek for the mass dampers with high effectiveness and robustness for the reduction of the undesirable vibrations of structures under the ground acceleration. The structure is represented by the mode-generalized system corresponding to the specific vibration mode that needs to be controlled. In light of the developed dynamic magnification factors (DMF) of the DTMD structure system, the criterion used for assessing the optimum parameters and effectiveness of the DTMD is selected as the minimization of the minimum values of the maximum DMF of the structure with the DTMD. With resorting to the maximum DMF of both the larger and smaller TMDs in the DTMD, the stroke of the DTMD is simultaneously investigated too. It is highlighted that a novel optimum objective function has been proposed in order to acquire high robust control system. Consequently, the two types of optimum goal functions (including the optimum goal function commonly used) have been applied for the optimum searching of the DTMD. The numerical results indicate that the DTMD designed in terms of the second type of optimum objective functions (i.e. the novel optimum objective function) practically provides the same effectiveness and robustness to the changes in the drift frequency ratio (DFR) as the multiple tuned mass dampers (MTMD) with the distributed natural frequencies with the total number of the TMD units equal to five and with equal total mass ratio. Likewise, the DTMD designed with resort to the second type of optimum objective functions can practically attain the same effectiveness as the TMD with equal total mass ratio. More importantly, in the robustness to the changes in the DFR, the DTMD is significantly better than the TMD, whereas in the robustness to the natural frequency tuning (NFT), measured by the
Optimum testing of multiple hypotheses in quantum detection theory
NASA Technical Reports Server (NTRS)
Yuen, H. P.; Kennedy, R. S.; Lax, M.
1975-01-01
The problem of specifying the optimum quantum detector in multiple hypotheses testing is considered for application to optical communications. The quantum digital detection problem is formulated as a linear programming problem on an infinite-dimensional space. A necessary and sufficient condition is derived by the application of a general duality theorem specifying the optimum detector in terms of a set of linear operator equations and inequalities. Existence of the optimum quantum detector is also established. The optimality of commuting detection operators is discussed in some examples. The structure and performance of the optimal receiver are derived for the quantum detection of narrow-band coherent orthogonal and simplex signals. It is shown that modal photon counting is asymptotically optimum in the limit of a large signaling alphabet and that the capacity goes to infinity in the absence of a bandwidth limitation.
50 CFR 648.20 - Maximum optimum yield (OYs).
Code of Federal Regulations, 2010 CFR
2010-10-01
... Measures for the Atlantic Mackerel, Squid, and Butterfish Fisheries § 648.20 Maximum optimum yield (OYs...) Mackerel—that quantity of mackerel that is less than or equal to the allowable biological catch (ABC) in...
Performance characteristics of aerodynamically optimum turbines for wind energy generators
NASA Technical Reports Server (NTRS)
Rohrbach, C.; Worobel, R.
1975-01-01
This paper presents a brief discussion of the aerodynamic methodology for wind energy generator turbines, an approach to the design of aerodynamically optimum wind turbines covering a broad range of design parameters, some insight on the effect on performance of nonoptimum blade shapes which may represent lower fabrication costs, the annual wind turbine energy for a family of optimum wind turbines, and areas of needed research. On the basis of the investigation, it is concluded that optimum wind turbines show high performance over a wide range of design velocity ratios; that structural requirements impose constraints on blade geometry; that variable pitch wind turbines provide excellent power regulation and that annual energy output is insensitive to design rpm and solidity of optimum wind turbines.
... Jacksonian seizure; Seizure - partial (focal); Temporal lobe seizure; Epilepsy - partial seizures ... Abou-Khalil BW, Gallagher MJ, Macdonald RL. Epilepsies. In: Daroff ... Practice . 7th ed. Philadelphia, PA: Elsevier; 2016:chap 101. ...
... Jacksonian seizure; Seizure - partial (focal); Temporal lobe seizure; Epilepsy - partial seizures ... Abou-Khalil BW, Gallagher MJ, Macdonald RL. Epilepsies. In: Daroff RB, ... 6th ed. Philadelphia, PA: Elsevier Saunders; 2012:chap 67. ...
NASA Technical Reports Server (NTRS)
Vranish, John M. (Inventor)
2010-01-01
A partial gear bearing including an upper half, comprising peak partial teeth, and a lower, or bottom, half, comprising valley partial teeth. The upper half also has an integrated roller section between each of the peak partial teeth with a radius equal to the gear pitch radius of the radially outwardly extending peak partial teeth. Conversely, the lower half has an integrated roller section between each of the valley half teeth with a radius also equal to the gear pitch radius of the peak partial teeth. The valley partial teeth extend radially inwardly from its roller section. The peak and valley partial teeth are exactly out of phase with each other, as are the roller sections of the upper and lower halves. Essentially, the end roller bearing of the typical gear bearing has been integrated into the normal gear tooth pattern.
Optimum filters for narrow-band frequency modulation.
NASA Technical Reports Server (NTRS)
Shelton, R. D.
1972-01-01
The results of a computer search for the optimum type of bandpass filter for low-index angle-modulated signals are reported. The bandpass filters are discussed in terms of their low-pass prototypes. Only filter functions with constant numerators are considered. The pole locations for the optimum filters of several cases are shown in a table. The results are fairly independent of modulation index and bandwidth.
PID controller auto-tuning based on process step response and damping optimum criterion.
Pavković, Danijel; Polak, Siniša; Zorc, Davor
2014-01-01
This paper presents a novel method of PID controller tuning suitable for higher-order aperiodic processes and aimed at step response-based auto-tuning applications. The PID controller tuning is based on the identification of so-called n-th order lag (PTn) process model and application of damping optimum criterion, thus facilitating straightforward algebraic rules for the adjustment of both the closed-loop response speed and damping. The PTn model identification is based on the process step response, wherein the PTn model parameters are evaluated in a novel manner from the process step response equivalent dead-time and lag time constant. The effectiveness of the proposed PTn model parameter estimation procedure and the related damping optimum-based PID controller auto-tuning have been verified by means of extensive computer simulations. PMID:24035643
Investigating Labrador Sea warmth during the mid-Pliocene optimum with Eirik Drift sediments
NASA Astrophysics Data System (ADS)
Gorbey, D. B.; Winsor, K.; Carlson, A. E.; Mathias, A.; McKay, J. L.; Hatfield, R. G.
2013-12-01
As anthropogenic CO2 emissions continue to rise, the mid-Pliocene Optimum (3.3-3.0 Ma) is the most relevant analog to the present because it was the last time that atmospheric CO2 may have reached ~400 ppm. Proxy records suggest global warming in response to this atmospheric CO2 forcing, which is generally simulated by climate models. Unfortunately, no temperature estimates exist at present from the Labrador Sea for the mid-Pliocene. Here we create the first δ18O record of the Labrador Sea during the Pliocene, including the mid-Pliocene Optimum, using the planktonic foraminiferal species Globigerina bulloides in order to reconstruct paleotemperature. Changes in G. bulloides δ18O relative to Holocene δ18O will provide the first insight into the response of the Labrador Sea to mid-Pliocene Optimum CO2 concentrations. Our preliminary analysis of G. bulloides δ18O finds only 0-1° C of warming during the mid-Pliocene Optimum relative to the Holocene.
Laparoscopic total and partial nephrectomy.
Lee, Benjamin R
2002-01-01
Laparoscopic radical nephrectomy has established its role as a standard of care for the management of renal neoplasms. Long term follow-up has demonstrated laparoscopic radical nephrectomy has shorter patient hospitalization and effective cancer control, with no significant difference in survival compared with open radical nephrectomy. For renal masses less than 4cm, partial nephrectomy is indicated for patients with a solitary kidney or who demonstrate impairment of contralateral renal function. The major technical issue for success of laparoscopic partial nephrectomy is bleeding control and several techniques have been developed to achieve better hemostatic control. Development of new laparoscopic techniques for partial nephrectomy can be divided into 2 categories: hilar control and warm ischemia vs. no hilar control. Development of a laparoscopic Satinsky clamp has achieved en bloc control of the renal hilum in order to allow cold knife excision of the mass, with laparoscopic repair of the collecting system, if needed. Combination of laparoscopic partial nephrectomy with ablative techniques has achieved successful excision of renal masses with adequate hemostasis without hilar clamping. Other techniques without hilar control have been investigated and included the use of a microwave tissue coagulator. In conclusion, laparoscopic radical nephrectomy for renal cell carcinoma has clearly demonstrated low morbidity and equivalent cancer control. The rates for local recurrences and metastatic spread are low and actuarial survival high. Furthermore, laparoscopic partial nephrectomy has demonstrated to be technically feasible, with low morbidity. With short term outcomes demonstrating laparoscopic partial nephrectomy as an efficacious procedure, the role of laparoscopic partial nephrectomy should continue to increase. PMID:15748397
A theoretical analysis of optimum consumer population and its control.
Jiang, Z; Mao, Z; Wang, H
1994-01-01
Material production is related to population consumption in every society. Consumption also constantly transforms materials, energy, and information. In this sense, consumption provides both impetus for material production and a self-adapting mechanism for population development and control. Population structure variables affecting economic production can be divided according to non-adults, working-age work force and the elderly, social status, and urban-rural structure. The consumptive structures among people of different social status reflect different needs for social and economic development. The theoretical calculation of the consumer population in the national economy demonstrates that the national income in a certain year of a given national economy equals consumption fund plus accumulation fund where consumption fund includes social consumption fund and residential consumption fund. Social consumption fund is spent mostly on public utilities, administrative management, national defense, education, public health and urban construction, as well as on environment management and disaster relief. The residential consumption fund can be divided into basic expenditure such as clothing, food, shelter and transportation, and self-improvement expenditure such as recreation, education, and travel. As a result of economic development, not only the percentage of the expenditure on food will decrease and the percentage of the expenditure on clothing, shelter, transportation, and other daily necessities will increase, but expenses on recreation and education also will grow. Residential consumption is divided into subsistence consumption (Type I consumption) and self-improvement (recreation and education) consumption (Type II consumption) in order to determine consumer population and the degree of urbanization and its impact upon social and economic development. A moderate consumer population model of urban and rural areas was established by using the urban and rural
Widespread formation of cherts during the early Eocene climate optimum
NASA Astrophysics Data System (ADS)
Muttoni, G.; Kent, D. V.
2007-12-01
Radiolarian cherts in the Tethyan realm of Jurassic age were recently interpreted as resulting from high biosiliceous productivity along upwelling zones in subequatorial paleolatitudes the locations of which were confirmed by revised paleomagnetic estimates. However, the widespread occurrence of cherts in the Eocene suggests that cherts may not always be reliable proxies of latitude and upwelling zones. In a new survey of the global spatiotemporal distribution of Cenozoic cherts in Deep Sea Drilling Project (DSDP) and Ocean Drilling Program (ODP) sediment cores, we found that cherts occur most frequently in the Paleocene and early Eocene, with a peak in occurrences at ~50 Ma that is coincident with the time of highest bottom water temperatures of the early Eocene climatic optimum (EECO) when the global ocean was presumably characterized by reduced upwelling efficiency and biosiliceous productivity. Cherts occur less commonly during the subsequent Eocene global cooling trend. Primary paleoclimatic factors rather than secondary diagenetic processes seem therefore to control chert formation. This timing of peak Eocene chert occurrence, which is supported by detailed stratigraphic correlations, contradicts currently accepted models that involve an initial loading of large amounts of dissolved silica from enhanced weathering and/or volcanism in a supposedly sluggish ocean of the EECO, followed during the subsequent middle Eocene global cooling by more vigorous oceanic circulation and consequent upwelling that made this silica reservoir available for enhanced biosilicification, with the formation of chert as a result of biosilica transformation during diagenesis. Instead, we suggest that basin-basin fractionation by deep-sea circulation could have raised the concentration of EECO dissolved silica especially in the North Atlantic, where an alternative mode of silica burial involving widespread direct precipitation and/or absorption of silica by clay minerals could have
Partially entangled states bridge in quantum teleportation
NASA Astrophysics Data System (ADS)
Cai, Xiao-Fei; Yu, Xu-Tao; Shi, Li-Hui; Zhang, Zai-Chen
2014-10-01
The traditional method for information transfer in a quantum communication system using partially entangled state resource is quantum distillation or direct teleportation. In order to reduce the waiting time cost in hop-by-hop transmission and execute independently in each node, we propose a quantum bridging method with partially entangled states to teleport quantum states from source node to destination node. We also prove that the designed specific quantum bridging circuit is feasible for partially entangled states teleportation across multiple intermediate nodes. Compared to two traditional ways, our partially entanglement quantum bridging method uses simpler logic gates, has better security, and can be used in less quantum resource situation.
Partial Derivatives of the Lambert Problem
NASA Technical Reports Server (NTRS)
Arora, Nitin; Russell, Ryan P.; Strange, Nathan
2014-01-01
A procedure for deriving analytic partial derivatives of the Lambert problem is presented. Using the universal, cosine based Lambert formulation; first order partial derivatives of the velocities with respect to the positions and times are developed. Taking advantage of inherent symmetries and intermediate variables, the derivatives are expressed in a computationally efficient form. The added cost of computing these partials is found to be approximately 10% to approximately 60% of the Lambert compute cost. The availability of analytic partial derivatives increases optimization speed, efficiency and allows for trajectory optimization formulations that implicitly enforce continuity constraints via embedded Lambert problems.
Digital Parallel Processor Array for Optimum Path Planning
NASA Technical Reports Server (NTRS)
Kremeny, Sabrina E. (Inventor); Fossum, Eric R. (Inventor); Nixon, Robert H. (Inventor)
1996-01-01
The invention computes the optimum path across a terrain or topology represented by an array of parallel processor cells interconnected between neighboring cells by links extending along different directions to the neighboring cells. Such an array is preferably implemented as a high-speed integrated circuit. The computation of the optimum path is accomplished by, in each cell, receiving stimulus signals from neighboring cells along corresponding directions, determining and storing the identity of a direction along which the first stimulus signal is received, broadcasting a subsequent stimulus signal to the neighboring cells after a predetermined delay time, whereby stimulus signals propagate throughout the array from a starting one of the cells. After propagation of the stimulus signal throughout the array, a master processor traces back from a selected destination cell to the starting cell along an optimum path of the cells in accordance with the identity of the directions stored in each of the cells.
Optimum irradiance distribution of concentrated sunlight for photovoltaic energy conversion
NASA Astrophysics Data System (ADS)
Benítez, Pablo; Mohedano, Rubén
1999-04-01
The irradiance distribution on a concentration photovoltaic cell that produces maximum conversion efficiency has been found with the tools of Variational Calculus. The analysis is two dimensional and can be applied to a comb-like double busbar solar cell illuminated by a line-focus concentrator. The optimum distribution is, in general, nonuniform, and depends on the internal parameters of the solar cell: the higher the contribution of the grid to the global cell series resistance, the lower the uniformity of the optimum irradiance distribution. In practical cases, the efficiency for uniform illumination is close to that of the optimum, but in the latter the irradiance close to the busbar may be noticeable higher than the average.
Determining the Optimum Number of Increments in Composite Sampling
Hathaway, John E.; Schaalje, G Bruce; Gilbert, Richard O.; Pulsipher, Brent A.; Matzke, Brett D.
2008-09-30
Composite sampling can be more cost effective than simple random sampling. This paper considers how to determine the optimum number of increments to use in composite sampling. Composite sampling can be more cost effective than simple random sampling. This paper considers how to determine the optimum number of increments to use in composite sampling. Composite sampling terminology and theory are outlined and a method is developed which accounts for different sources of variation in compositing and data analysis. This method is used to define and understand the process of determining the optimum number of increments that should be used in forming a composite. The blending variance is shown to have a smaller range of possible values than previously reported when estimating the number of increments in a composite sample. Accounting for differing levels of the blending variance significantly affects the estimated number of increments.
Optimum climb and descent trajectories for airline missions
NASA Technical Reports Server (NTRS)
Erzberger, H.
1981-01-01
The characteristics of optimum fixed-range trajectories whose structure is constrained to climb, steady cruise, and descent segments are derived by application of optimal control theory. The performance function consists of the sum of fuel and time costs, referred to as direct operating cost (DOC). The state variable is range to go and the independent variable is energy. In this formulation a cruise segment always occurs at the optimum cruise energy for sufficiently large range. At short ranges (400 n. mi. and less), a cruise segment may also occur below the optimum cruise energy. The existence of such a cruise segment depends primarily on the fuel flow vs thrust characteristics and on thrust constraints. If thrust is a free control variable along with airspeed, it is shown that such cruise segments will not generally occur. If thrust is constrained to some maximum value in climb and to some minimum in descent, such cruise segments generally will occur.
NASA Technical Reports Server (NTRS)
Hajela, P.; Chen, J. L.
1986-01-01
The present paper describes an approach for the optimum sizing of single and joined wing structures that is based on representing the built-up finite element model of the structure by an equivalent beam model. The low order beam model is computationally more efficient in an environment that requires repetitive analysis of several trial designs. The design procedure is implemented in a computer program that requires geometry and loading data typically available from an aerodynamic synthesis program, to create the finite element model of the lifting surface and an equivalent beam model. A fully stressed design procedure is used to obtain rapid estimates of the optimum structural weight for the beam model for a given geometry, and a qualitative description of the material distribution over the wing structure. The synthesis procedure is demonstrated for representative single wing and joined wing structures.
Photometric Error Analysis. IX: Optimum Use of Photomultipliers.
Young, A T
1969-12-01
A critical study of photomultipliers leads to the following conclusions: (1) the dark current observed in tubes with alkali-antimonide cathodes at room temperature is primarily due to gas ions, not thermionic emission; (2) deviation from idealized (simple Poisson) pulse-height distributions is primarily due to secondary electron loss, particularly in venetian blind multipliers; (3) pulse-counting provides better signal-to-noise ratio than any other simple detection scheme, and is not far from optimum detection in most cases. However, dc methods can approach pulse-counting quite closely if digital readout is used. A convenient method for determining optimum discriminator levels is presented, with examples. PMID:20076054
Theory of optimum radio reception methods in random noise
NASA Astrophysics Data System (ADS)
Gutkin, L. S.
1982-09-01
The theory of optimum methods of reception of signals on the background of random noise, widely used in development of any radioelectronic systems and devices based on reception and transmission of information (radar and radio controlled, radio communications, radio telemetry, radio astronomy, television, and other systems), as well as electroacoustical and wire communications sytems, is presented. Optimum linear and nonlinear filtration, binary and comples signal detection and discrimination, estimation of signal parameters, receiver synthesis for incomplete a priori data, special features of synthesis with respect to certain quality indicators, and other problems are examined.
A first course in optimum design of yacht sails
NASA Astrophysics Data System (ADS)
Sugimoto, Takeshi
1993-03-01
The optimum sail geometry is analytically obtained for the case of maximizing the thrust under equality and inequality constraints on the lift and the heeling moment. A single mainsail is assumed to be set close-hauled in uniform wind and upright on the flat sea surface. The governing parameters are the mast height and the gap between the sail foot and the sea surface. The lifting line theory is applied to analyze the aerodynamic forces acting on a sail. The design method consists of the variational principle and a feasibility study. Almost triangular sails are found to be optimum. Their advantages are discussed.
Optimum high temperature strength of two-dimensional nanocomposites
Monclús, M. A.; Molina-Aldareguía, J. M.; Polcar, T.; Llorca, J.
2013-11-01
High-temperature nanoindentation was used to reveal nano-layer size effects on the hardness of two-dimensional metallic nanocomposites. We report the existence of a critical layer thickness at which strength achieves optimal thermal stability. Transmission electron microscopy and theoretical bicrystal calculations show that this optimum arises due to a transition from thermally activated glide within the layers to dislocation transmission across the layers. We demonstrate experimentally that the atomic-scale properties of the interfaces profoundly affect this critical transition. The strong implications are that interfaces can be tuned to achieve an optimum in high temperature strength in layered nanocomposite structures.
Aerodynamic optimum design of transonic turbine cascades using Genetic Algorithms
NASA Astrophysics Data System (ADS)
Li, Jun; Feng, Zhenping; Chang, Jianzhong; Shen, Zuda
1997-06-01
This paper presents an aerodynamic optimum design method for transonic turbine cascades based on the Genetic Algorithms coupled to the inviscid flow Euler solver and the boundary-layer calculation. The Genetic Algorithms control the evolution of a population of cascades towards an optimum design. The fitness value of each string is evaluated using the flow solver. The design procedure has been developed and the behavior of the genetic algorithms has been tested. The objective functions of the design examples are the minimum mean-square deviation between the aimed pressure and computed pressure and the minimum amount of user expertise.
Optimum control forces for multibody systems with intermittent motion
NASA Technical Reports Server (NTRS)
Ider, Sitki Kemal; Amirouche, F. M. L.
1989-01-01
The objective is to address the continuity of motion when a dynamical system is suddenly subjected to constraint conditions. Motion discontinuity due to the initial constraint violation is avoided by prior control forces that adjust the motion and yield velocity and acceleration consistent at the point of application of the constraint. The optimum control forces are determined for a specified control interval. The method proposed provides an optimum adjustment of the system's motion and assures that the stresses developed at the system components are kept within acceptable limits. The procedures developed will be illustrated making use of inequality constraints applied to obstacle avoidance problems in robotics.
Optimum subsonic, high-angle-of-attack nacelles
NASA Technical Reports Server (NTRS)
Luidens, R. W.; Stockman, N. O.; Diedrich, J. H.
1979-01-01
The optimum design of nacelles that operate over a wide range of aerodynamic conditions and their inlets is described. For low speed operation the optimum internal surface velocity distributions and skin friction distributions are described for three categories of inlets: those with BLC, and those with blow in door slots and retractable slats. At cruise speed the effect of factors that reduce the nacelle external surface area and the local skin friction is illustrated. These factors are cruise Mach number, inlet throat size, fan-face Mach number, and nacelle contour. The interrelation of these cruise speed factors with the design requirements for good low speed performance is discussed.
Multiple symbol partially coherent detection of MPSK
NASA Technical Reports Server (NTRS)
Simon, M. K.; Divsalar, D.
1992-01-01
It is shown that by using the known (or estimated) value of carrier tracking loop signal to noise ratio (SNR) in the decision metric, it is possible to improve the error probability performance of a partially coherent multiple phase-shift-keying (MPSK) system relative to that corresponding to the commonly used ideal coherent decision rule. Using a maximum-likeihood approach, an optimum decision metric is derived and shown to take the form of a weighted sum of the ideal coherent decision metric (i.e., correlation) and the noncoherent decision metric which is optimum for differential detection of MPSK. The performance of a receiver based on this optimum decision rule is derived and shown to provide continued improvement with increasing length of observation interval (data symbol sequence length). Unfortunately, increasing the observation length does not eliminate the error floor associated with the finite loop SNR. Nevertheless, in the limit of infinite observation length, the average error probability performance approaches the algebraic sum of the error floor and the performance of ideal coherent detection, i.e., at any error probability above the error floor, there is no degradation due to the partial coherence. It is shown that this limiting behavior is virtually achievable with practical size observation lengths. Furthermore, the performance is quite insensitive to mismatch between the estimate of loop SNR (e.g., obtained from measurement) fed to the decision metric and its true value. These results may be of use in low-cost Earth-orbiting or deep-space missions employing coded modulations.
Optimum Design of Aerospace Structural Components Using Neural Networks
NASA Technical Reports Server (NTRS)
Berke, L.; Patnaik, S. N.; Murthy, P. L. N.
1993-01-01
The application of artificial neural networks to capture structural design expertise is demonstrated. The principal advantage of a trained neural network is that it requires a trivial computational effort to produce an acceptable new design. For the class of problems addressed, the development of a conventional expert system would be extremely difficult. In the present effort, a structural optimization code with multiple nonlinear programming algorithms and an artificial neural network code NETS were used. A set of optimum designs for a ring and two aircraft wings for static and dynamic constraints were generated using the optimization codes. The optimum design data were processed to obtain input and output pairs, which were used to develop a trained artificial neural network using the code NETS. Optimum designs for new design conditions were predicted using the trained network. Neural net prediction of optimum designs was found to be satisfactory for the majority of the output design parameters. However, results from the present study indicate that caution must be exercised to ensure that all design variables are within selected error bounds.
Determination of optimum load for a solar cell
Kothari, L.S.; Mathur, P.C.; Kapoor, A.; Saxena, P.; Sharma, R.P.
1982-08-01
An expression for load for maximum power transfer from a real solar cell, having resistive and current leakage losses, has been obtained using Lagrange's method of undetermined multipliers for solving the transcendental current-voltage relationship. The theoretical results are compared with the experimental measurements of the optimum load for p-n junction solar cells for various illumination levels.
The Optimum Conditions of Foreign Languages in Primary Education
ERIC Educational Resources Information Center
Giannikas, Christina Nicole
2014-01-01
The aim of the paper is to review the primary language learning situation in Europe and shed light on the benefits it carries. Early language learning is the biggest policy development in education and has developed in rapid speed over the past 30 years; this article considers the effects and advantages of the optimum condition of an early start,…
An Application of Calculus: Optimum Parabolic Path Problem
ERIC Educational Resources Information Center
Atasever, Merve; Pakdemirli, Mehmet; Yurtsever, Hasan Ali
2009-01-01
A practical and technological application of calculus problem is posed to motivate freshman students or junior high school students. A variable coefficient of friction is used in modelling air friction. The case in which the coefficient of friction is a decreasing function of altitude is considered. The optimum parabolic path for a flying object…
Optimum position for wells producing at constant wellbore pressure
Camacho-Velazquez, R.; Rodriguez de la Garza, F.; Galindo-Nava, A.; Prats, M.
1994-12-31
This paper deals with the determination of the optimum position of several wells, producing at constant different wellbore pressures from a two-dimensional closed-boundary reservoirs, to maximize the cumulative production or the total flow rate. To achieve this objective they authors use an improved version of the analytical solution recently proposed by Rodriguez and Cinco-Ley and an optimization algorithm based on a quasi-Newton procedure with line search. At each iteration the algorithm approximates the negative of the objective function by a cuadratic relation derived from a Taylor series. The improvement of rodriguez and Cinco`s solution is attained in four ways. First, an approximation is obtained, which works better at earlier times (before the boundary dominated period starts) than the previous solution. Second, the infinite sums that are present in the solution are expressed in a condensed form, which is relevant for reducing the computer time when the optimization algorithm is used. Third, the solution is modified to take into account the possibility of having wells starting to produce at different times. This point allows them to deal with the problem of getting the optimum position for an infill drilling program. Last, the solution is extended to include the possibility of changing the value of wellbore pressure or being able to stimulate any of the wells at any time. When the wells are producing at different wellbore pressures it is found that the optimum position is a function of time, otherwise the optimum position is fixed.
Optimum conditions for the turkey lymphocyte transformation test.
Barta, O; Barta, V; Domermuth, C H; Pierson, F W
1992-01-01
Optimum conditions for turkey lymphocyte transformation tests were determined. Thrice-washed turkey buffy-coat cells obtained after slow centrifugation (40 x g, 10 minutes) responded well to mitogenic stimulation. Turkey lymphocytes isolated on Ficoll-containing separation media largely lost their ability to respond to mitogens. Maximum responses were obtained with 2 x 10(7) lymphoid cells/ml. Responses to the mitogens were greatest when bovine fetal serum was used at a 2.5% concentration or pooled turkey serum and autologous plasma were used at a 1.25% concentration. Higher concentrations of turkey serum or plasma decreased the responses when sub-optimum doses of concanavalin-A (Con A) or phytohemagglutinin-P (PHA-P) were used. Serum-free cultures gave higher stimulation indices than cultures with serum only when sub-optimum doses of Con A or PHA-P were used. Optimum mitogen concentrations varied with individual birds, timing of the culture, temperature of incubation, and serum concentration in the cultures. Responses were usually greatest with final concentrations of 5 micrograms Con A/ml, 10 micrograms PHA-P/ml, and 20 micrograms pokeweed mitogen (PWM)/ml and when the cultures were incubated in 96-well microplates at 40 C in humidified air with 5% CO2 for 40-42 hours with pulsing with 3H-thymidine during the final 16 hours of incubation. PMID:1627110
Optimum Onager: The Classical Mechanics of a Classical Siege Engine
ERIC Educational Resources Information Center
Denny, Mark
2009-01-01
The onager is a throwing weapon of classical antiquity, familiar to both the ancient Greeks and Romans. Here we analyze the dynamics of onager operation and derive the optimum angle for launching a projectile to its maximum range. There is plenty of scope for further considerations about increasing onager range, and so by thinking about how this…
On the Optimum Predictive Potential of Change Measure.
ERIC Educational Resources Information Center
Gupta, J. K.; And Others
1988-01-01
How the validity of gain scores varies with the standard deviations of pretest and posttest scores and the correlation between the two are analyzed. Earlier findings that under realistic testing conditions difference scores can have excellent predictive value are supported. Conditions under which gain scores have optimum validity are specified.…
COPTRAN - A method of optimum communication systems design
NASA Technical Reports Server (NTRS)
Brinkman, K. L.; Pratt, W. K.; Stokes, L. S.; Weber, J. W.
1970-01-01
Single set of mathematical expressions describes system cost and probability of error of data transmission in terms of four basic parameters in the link equation. A Lagrange multiplier sets up equations whose solutions yield the optimum values for system design considerations and weight and cost values.
Physics of Partially Ionized Plasmas
NASA Astrophysics Data System (ADS)
Krishan, Vinod
2016-05-01
Figures; Preface; 1. Partially ionized plasmas here and everywhere; 2. Multifluid description of partially ionized plasmas; 3. Equilibrium of partially ionized plasmas; 4. Waves in partially ionized plasmas; 5. Advanced topics in partially ionized plasmas; 6. Research problems in partially ionized plasmas; Supplementary matter; Index.
Optimum design for pipe-support allocation against seismic loading
Hara, Fumio; Iwasaki, Akira
1996-12-01
This paper deals with the optimum design methodology of a piping system subjected to a seismic design loading to reduce its dynamic response by selecting the location of pipe supports and whereby reducing the number of pipe supports to be used. The author employs the Genetic Algorithm for obtaining a reasonably optimum solution of the pipe support location, support capacity and number of supports. The design condition specified by the support location, support capacity and the number of supports to be used is encored by an integer number string for each of the support allocation candidates and they prepare many strings for expressing various kinds of pipe-support allocation state. Corresponding to each string, the authors evaluate the seismic response of the piping system to the design seismic excitation and apply the Genetic Algorithm to select the next generation candidates of support allocation to improve the seismic design performance specified by a weighted linear combination of seismic response magnitude, support capacity and the number of supports needed. Continuing this selection process, they find a reasonably optimum solution to the seismic design problem. They examine the feasibility of this optimum design method by investigating the optimum solution for 5, 7 and 10 degree-of-freedom models of piping system, and find that this method can offer one a theoretically feasible solution to the problem. They will be, thus, liberated from the severe uncertainty of damping value when the pipe support guaranties the design capacity of damping. Finally, they discuss the usefulness of the Genetic Algorithm for the seismic design problem of piping systems and some sensitive points when it will be applied to actual design problems.