Investition bei Unsicherheit als Erklärung für hohe implizite Diskontraten bei Energiesparinvestitionen

Zusammenfassung Die Tatsache, daß Konsumenten (und auch Unternehmen) hohe implizite Diskontraten bei der Entscheidung über Energiesparinvestitionen verwenden, wird häufig beobachtet. Dies wird fast einhellig als Marktversagen angesehen und hat viele Analytiker dazu veranlaßt, entweder für öffentliche oder bezuschußte Energiesparinvestitionen zu plädieren. In dieser Arbeit wird die Theorie der Realoptionen auf ein bekanntes Beispiel angewandt: der Wahl zwischen konventioneller Glühbirne und Sparlampe bei unterstellter Risikoneutralität des Entscheidungsträgers. Es zeigt sich, daß die dem Wert der Option des Abwartens und Aufschiebens der Investition Rechnung tragenden impliziten Diskontraten nahe den beobachteten Werten liegen. Deshalb bedarf die Schlußfolgerung eines Marktversagens aus hohen impliziten Diskontraten einer sorgfältigeren und feineren Analyse. Dies trifft a fortiori auf due Empfehlung von Energiesparprogrammen zu.Die Autoren sind zwei anonymen Gutachtern zu Dank für ihre konstruktiven Vorschläge verpflichtet     

Finite element recovery techniques for local quantities of linear problems using fundamental solutions

We show that local quantities of interest such as displacements or stresses of a FE–solution can be calculated with improved accuracy if fundamental solutions are employed. The approach is based on Bettis theorem and an integral representation of the local quantities via Greens function. The unknown Greens function is split into a regular part and a fundamental solution so that only the regular part must be approximated on the finite element ansatz space. Some numerical studies for linear elasticity will illustrate our approach.     

The Middle Product Algorithm I

We present new algorithms for the inverse, division, and square root of power series. The key trick is a new algorithm – MiddleProduct or, for short, MP – computing the n middle coefficients of a (2n–1)×n full product in the same number of multiplications as a full n×n product. This improves previous work of Brent, Mulders, Karp and Markstein, Burnikel and Ziegler. These results apply both to series and polynomials.Received: 20 July 2000     

The dependence of stress intensity factors and weight functions on elastic constants

We investigate the dependence of stress intensity factors (SIFs) on elastic constants in two-dimensional elastic isotropic bodies. Bueckners weight function theory is used for the derivation of the dependence of SIFs on elastic constants. The dependence of SIFs on Poissons ratio shows up when the resultant tractions on each of the contours L _k separately is not zero in multiply connected bodies. As an example we calculate K ₁ for Griffith crack under concentrated loading applied on the upper crack face.     

A new variational self-regular traction-BEM formulation for inter-element continuity of displacement derivatives

In this work, a non-symmetric variational approach is derived to enforce C ^1, continuity at inter-element nodes for the self-regular traction-BIE. This variational approach uses only Lagrangian C ⁰ elements. Two separate algorithms are derived. The first one enforces C ^1, continuity at smooth inter-element nodes, and the second enforces continuity of displacement derivatives in global coordinates at corner nodes, where C ^1, continuity cannot be enforced. The variational formulation for the traction-BIE is implemented in this work for two elastostatics problems with various discretizations and polynomial interpolants. Local and global measures of the discretization error are obtained by means of an error estimator recently derived by the authors. Comparisons are also made with the displacement-BIE, which does not require C ^1, continuity for the displacement. The lack of smoothness of the displacement derivatives at the inter-element nodes is shown to be an important source of both local and global error for the traction-BIE formulation, especially for quadratic elements. The accuracy of the boundary solution obtained from the traction-BIE improves significantly when C ^1, continuity is enforced where possible, i.e., at the smooth inter-element nodes only. The first author acknowledges the support received from CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico. The third author gratefully acknowledges support by the National Science Foundation (CTS-9983961). The fourth author acknowledges the support received from FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais.     

Heat transfer in a viscoelastic boundary layer flow through a porous medium

This paper examines the viscoelastic fluid flow and heat transfer characteristics in a saturated porous medium over an impermeable stretching surface with frictional heating and internal heat generation or absorption. The heat transfer analysis has been carried out for two different heating processes, namely (i) with prescribed surface temperature (PST-case) and (ii) prescribed surface heat flux (PHF-case). The governing equations for the boundary layer flow problem result similar solutions. For the specified five boundary conditions, it is not possible to solve directly the resulting sixth-order nonlinear ordinary differential equation. For the present incompressible boundary layer flow problem with constant physical parameters, the momentum equation is decoupled from the energy equation. Two closed–form solutions for the momentum equation are obtained and identified the realistic solution of the physical problem. Exact solution for the velocity field and the skin-friction are obtained. Also, the solution for the temperature and the heat transfer characteristics are obtained in terms of Kummers function. Asymptotic results for the temperature function for large Prandtl numbers are presented. The work due to deformation in the energy equation, which is essential and escaped from the attention of researchers while formulating the visco-elastic boundary layer flow problems, is considered. Drastic variation in the values of heat transfer coefficient is observed when the work due to deformation is ignored.The authors would like to thank the reviewers for their valuable comments/ suggestions to improve the clarity of the paper.     

Density of α-pinene, Β-pinene,limonene, and essence of turpentine

Densities of ga-pinene, -pinene, limonene, and essence of turpentine have been measured at 293.15, 298.15, 303.15, 308.15, and 313.15 K, at atmospheric pressure, with a mechanical oscillator densimeter. Benzene and cyclohexane were used as calibration fluids. The precision is of the order of 0.01 kg · m^–3, while the accuracy is estimated to be 0.1%. A linear representation of the variation of the density with temperature reproduces the experimental data within 0.2%.     

Maximizing pseudoconvex transportation problem: a special type

The paper discusses a non-concave fractional programming problem aiming at maximization of a pseudoconvex function under standard transportation conditions. The pseudoconvex function considered here is the product of two linear functions contrasted with a positive valued linear function. It has been established that optimal solution of the problem is attainable at an extreme point of the convex feasible region. The problem is shown to be related to indefinite quadratic programming which deals with maximization of a convex function over the given feasible region. It has been further established that the local maximum point of this quadratic programming problem is the global maximum point under certain conditions, and its optimal solution provides an upper bound on the optimal value of the main problem. The extreme point solutions of the indefinite quadratic program are ranked to tighten the bounds on the optimal value of the main problem and a convergent algorithm is developed to obtain the optimal solution.     

A scenario-driven conceptual design information model and its formation

This study describes a scenario-driven conceptual design information model and its formation from the viewpoint of the designers cognition, which is a fundamental part of practical design support tools. Four design meetings were observed in a company, at intervals of several weeks, in order to derive the model. The model consists of information elements generated through the cognitive design problem-solving process, which is a basic design process defined in this study. The study describes the relationship among these information elements, which illustrate the design information model and its formation. The model described in this study is based on scenarios, which promote the evolution of product design. Examples of designers discourse in the design meetings are presented to validate the model.     

Effects of measurement errors on sample monitoring reliability

Results are presented on the effects of measurement errors on items in routine production as regards the reliability of results on sampling inspection obtained by Monte Carlo simulation. The customers and the makers risks are examined in relation to the distributions of the measurement errors and the values of them.Translated from Izmeritelnaya Tekhnika, No. 12, pp. 8–11, December, 2004.This revised version was published online in April 2005 with a corrected cover date.     

Microstructure Development and Property Improvement in Mill Products Produced from Ingot Metallurgy and Powder Metallurgy Ni-Based Superalloys of the Same Chemical Composition

Despite projected inroads from competing materials Ni-based superalloys remain the material of choice in the hot sections of advanced gas turbine engines. In this paper microstructural development and improvement of mechanical properties in mill products produced by ingot metallurgy (IM) and powder metallurgy (PM) techniques are discussed. Particular attention is given to approaches to improvement in ingot ductility. Thermomechanical treatment schemes used during forging of a complex-alloyed Ni-based superalloy are recommended. It is demonstrated that the PM technique used for production of this complex-alloyed superalloy is a promising approach. On the basis of the studies carried out the salient features of the structure of material produced both by both IM and PM techniques have been defined. The mechanical properties of two versions of an advanced Ni-base superalloy produced by IM and PM techniques are discussed. The best combination of mechanical properties are exhibited by a PM material with a necklace structure; and this latter structure is superior to a fine grained structure for IM product also.     

Development of methods and instruments of the Russian service for determination of the Earth’s orbital parameters

The state and future outlook of research to determine the Earths orbital parameters, i.e., Universal Time and the coordinates of the pole, carried out by the State Time and Frequency Service and in calculations of the Earths orbital parameters are described.Translated from Izmeritelnaya Tekhnika, No. 1, pp. 24–27, January, 2005.     

Phonon Raman scattering of R2CuO4 (R = Pr, Nd, Sm, and Gd)

For Gd₂CuO₄, a new symmetry-forbidden phonon for the tetragonal T structure is observed. This implies that oxygen in the CuO₂ plane is locally distorted along the CuO₂ plane. Such distortion has never been observed for other T-type superconductors, which show superconductivity by Ce doping. The disappearance of superconductivity for Gd can be correlated with the appearance of the distortion due to oxygen in the CuO₂ plane.     

Experience in polyharmonic analysis of the parameters of the earth’s rotation

A method for approximating time series by an nth degree trigonometric polynomial for a series of parameters of the Earths rotation, calculated from GPS and GLONASS measurements, is tested. Satisfactory agreement is obtained between the model and experimental data. The results can be used for complex modeling and forecasting of the parameters of the Earths rotation.Translated from Izmeritelnaya Tekhnika, No. 12, pp. 40–42, December, 2004.This revised version was published online in April 2005 with a corrected cover date.     

[111] Heterostructures for Spin Devices

The symmetry properties of [111] quantum wells (QWs) and superlattices, and in particular the fact that the symmetry is not reduced when bulk inversion asymmetry (BIA) is supplemented with structural inversion asymmetry [SIA (Rashba)], have important consequences for spin dynamics and transport. We compute the effective spin Hamiltonians for [111] and [110] structures, and show that for the [111] case the splitting can be made to vanish to lowest order when BIA and SIA effects are of equal strength. As a consequence, the Dyakonov–Perel spin relaxation mechanism is suppressed for all spin components. This effect forms the base for an improved version of the Datta–Das and a recently proposed family of spin transistors. For [110]-grown QWs, the effect of SIA is to augment the spin relaxation rate of the component perpendicular to the well. We derive analytical expressions for the spin lifetime tensor and its proper axes, and see that they are dependent on the relative magnitude of the BIA- and SIA-induced splittings.     

Observation ofd-wave interference pattern:Short junction is crucial

The properties of a one-dimensional 0--Josephson junction, consiting of ans-d junction or selected boundaries between three suitably orientedd-wave superconductors, are studied. It is shown that ad-wave type interference pattern can only be observed in the field-modulated critical current if the junction is short compared to the Josephson penetration depth. However, the behavior of a 0- junction is found to be indistinguishable from that of a 0-junction betweens-wave superconductors in the long junction limit, due to the formation of a -vortex.     

A finite element post-processed Galerkin method for dimensional reduction in the non-linear dynamics of solids. Applications to shells

In this paper we introduce the finite element version of the so-called post-processed Galerkin method into the field of solid mechanics and apply the new technique to the dynamics of shells. The proposed post-processed method provides low-cost means to lift low-dimensional solutions to high-dimensional solutions. It is the very fact that the kinematical fields are improved to higher orders which makes the method of great interest. Our shell theory is geometrically exact in the sense that all non-linearities are included in the formulation. For time integration an energy/momentum scheme is used to enhance integration stability. Two hierarchical enhanced finite elements are formulated, on the basis of which a specific post-processed method is then developed. With the help of some examples of non-linear shell vibrations, a critical examination and validation of the post-processed method is carried out.     

Thermophysical Properties of the Zr–0.01Nb Alloy at Various Heating Rates and Repeated Cycles of Heating–Cooling

The results of an experimental study of the heat capacity, enthalpy, electrical resistivity, and spectral emissivity (for the wavelength of 0.65 m) of the Zr–0.01Nb alloy in the temperature range from 900 to 2000 K are presented. The study was carried out using subsecond pulse heating of the samples by passing electrical current through them. Experiments were conducted at different heating rates (10³ to 10⁴K·s^–1), and a series of experiments consisted of several cycles of pulse heating and subsequent cooling. The effect of these parameters on the temperature dependence of thermophysical properties in the region of the –transition was studied. With an increase in the heating rate, the temperature of the – transition, and the maximum in the heat capacity shifted to higher temperatures. There are significant differences in properties over the temperature range of the – transition for the various heating cycles.     

Solid-liquid phase equilibria of (α-methylnaphthalene + β-methylnaphthalene) and (chlorobenzene + bromobenzene) systems under high Pressures

Solid-liquid phase equilibria of the (-methylnaphthalene + -methylnaphthalene) and the (chlorobenzene + bromobenzene) systems have been investigated at temperatures from 278 to 343 K and pressures up to 500 MPa using a high-pressure optical vessel. The uncertainties of the measurements of temperature, pressure, and composition were within ±0.1 K, ±0.5 MPa, and ±0.001 mole fraction, respectively. In both systems, the freezing and melting pressures at a constant composition increase almost linearly with increasing temperatures. In the former system, where the two components can form a solid solution with one another to a limit extent, the eutectic point shifts to a higher temperature and to a -methylnaphthalene-rich composition with increasing pressures. In the latter system, where the two components are completely soluble in each other in the solid phase, the freezing points of all mixtures lie between those of the pure components at each pressure. It is found that the coexistence curves obtained can be expressed by a quadratic equation in pressure.