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• 1
Electronic Resource
Springer
ISSN: 1588-2780
Source: Springer Online Journal Archives 1860-2000
Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
Notes: Abstract The dynamic adsorption of Kr and Xe in activated charcoal were measured. The temperature dependence of breakthrough curves for individual isotopes of85mKr,87Kr,88Kr and135Xe have been determined from the γ-spectra at temperatures from 78 K to 291 K. The effective hold up and dynamic adsorption coefficient have been deduced. We find that adsorption is very sensitive to temperature and also depends on the size rather than on the mass of the adsorbed atom. Form total growth radioactivity, the time dependent brakthrough curves at the temperatures of 113, 195 and 220 K have been constructed. The curves were analyzed and compared with the model calculations. Fick's law describing the mass transfer of gas into porous solid was employed to obtain the adsorption coefficient from fitting the experimental data. The results show fairly good agreement between model predictions and the experiments.
Type of Medium: Electronic Resource
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• 2
Electronic Resource
Springer
ISSN: 1573-2878
Keywords: D-convex set functions ; D-extreme points ; vector-valued Lagrangian functions ; primal maps ; dual maps
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics
Notes: Abstract Using the concept of vector-valued Lagrangian functions, we characterize a special class of solutions,D-solutions, of a multiobjective programming problem with set functions in which the domination structure is described by a closed convex coneD. Properties of two perturbation functions, primal map and dual map, are also studied. Results lead to a general duality theorem.
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• 3
Electronic Resource
Springer
ISSN: 1573-4862
Keywords: Crack detection ; modal testing ; nondestructive evaluation ; fracture mechanics ; structure ; finite element method
Source: Springer Online Journal Archives 1860-2000
Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
Notes: Abstract An energy method for identifying the size of a crack at given location in structures using one measured eigencouple of the cracked structures is presented. The method utilizes the maximum strain energies of the structures both with and without a crack and the additional strain energy induced by the crack to construct the energy balance equation from which the size of the crack is evaluated through an iteration procedure. A pair of measured vibration frequency and mode shape of the cracked structure is used in a free vibration analysis to derive for its maximum strain energy. The maximum inertia force of the cracked structure is then applied to the uncracked structure with known stiffness and the resulting strain energy of the uncracked structure is obtained in a finite element analysis. Fracture mechanics is used to derive for the additional strain energy induced by the crack. Experimental investigations of several cracked free-free beams are performed to validate the proposed method. Examples of the identification of crack sizes for a number of damaged beam structures are given to further illustrate the feasibility and effectiveness of the present method. Overall the results are encouraging showing that the present method has the prospect of becoming an alternative approach for crack size detection.
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• 4
Electronic Resource
Springer
ISSN: 1573-2878
Keywords: Multiobjective programming problems ; D-convex set functions ; D-extreme points ; properD-solutions
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics
Notes: Abstract A special class of solutions for multiobjective programming problems with set functions is considered. A subset of nondominated solutions, called properD-solution set, with respect to a given domination structure is characterized under two situations, with and without inequality constraints.
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• 5
Electronic Resource
Springer
ISSN: 1573-2878
Keywords: Multiobjective programming ; set functions ; Lagrange multiplier theorems ; zero-like functions ; proper D-solutions
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics
Notes: Abstract In this paper, Lagrange multiplier theorems are developed for the cases of single-objective and multiobjective programming problems with set functions. Properly efficient solutions are also characterized by subdifferentials and zero-like functions.
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• 6
Electronic Resource
Springer
Probability theory and related fields 84 (1990), S. 505-520
ISSN: 1432-2064
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics
Notes: Summary For a critical binary branching Bessel process starting fromx≫1 and stopped atx=1, we prove some conditional limit laws of the number of particles arriving atx=1 before a scaled large time. Five regions of the dimensional index of a Bessel process: −∞〈d〈2,d=2, 2〈d〈4,d=4 and 4〈d〈∞ are showed to have somewhat different behaviors. Our probabilistic results are proved by analyzing differential equations satisfied by generating functions. A salient theme is a comparison principle technique deliberately used to estimate solutions of $$u_t - \left( {D^2 + \frac{{d - 1}}{x}D} \right)u + u^p = 0$$ inR +×R + wherep is greater than 1. The casep=2 corresponds to the process considered.
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• 7
Electronic Resource
Springer
Probability theory and related fields 105 (1996), S. 227-254
ISSN: 1432-2064
Keywords: 60F 10 ; 35J55
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics
Notes: Summary The diffusion-transmutation processes are considered as the diffusivities are of order ε,ε→0 and the transmutation intensities are of order ε−1. We prove a large deviation principle for the position joint with the type occupation times as ε→0 and study the exit problem for this process. We consider the Levinson case where a trajectory of the average drift field exits from a domain in finite time in a regular way and the large deviation case where the average drift field on the boundary points inward at the domain. The exit place and the type distribution at the exit time are determined as ε→0; this gives the limit of the Dirichlet problems for the corresponding PDE systems with a parameter ε→0.
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• 8
Electronic Resource
Springer
Probability theory and related fields 105 (1996), S. 227-254
ISSN: 1432-2064
Keywords: Mathematics Subject classification (1991): 60F10 ; 35J55
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics
Notes: Summary. The diffusion-transmutation processes are considered as the diffusivities are of order ɛ, ɛ→ 0 and the transmutation intensities are of order ɛ −1 . We prove a large deviation principle for the position joint with the type occupation times as ɛ→ 0 and study the exit problem for this process. We consider the Levinson case where a trajectory of the average drift field exits from a domain in finite time in a regular way and the large deviation case where the average drift field on the boundary points inward at the domain. The exit place and the type distribution at the exit time are determined as ɛ→ 0; this gives the limit of the Dirichlet problems for the corresponding PDE systems with a parameter ɛ→ 0.
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• 9
Electronic Resource
Springer
Probability theory and related fields 106 (1996), S. 39-70
ISSN: 1432-2064
Keywords: Mathematics Subject classification (1991): 60J60 ; 35K55
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics
Notes: Summary.  We study systems of reaction – diffusion equations of KPP-type with the coefficients and nonlinear terms slowly varying in the space variables. The long time behavior of the solution to such systems can be characterized by the motion of wave fronts. We describe the wave front motion, using the Feynman–Kac formula and the large deviation principle for the corresponding diffusion – transmutation process. We give a geometrical description of the motion in the examples and show some effects which appear in case of systems but not in the single RDE’s.
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• 10
Electronic Resource
Hoboken, NJ : Wiley-Blackwell
AIChE Journal 40 (1994), S. 1976-1982
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: A 200-s PSA cycle involving both pressure equalization and product backfill steps has been experimentally studied on a four-bed system, where LINDE 5 A zeolites were used as the adsorbent to separate oxygen from air. This cycle is operated under a pressure ratio of 4.3. During the experiment, the pressure history and flow rates, as well as the concentration of the product stream have been continuously monitored. This is the first time detailed experimental data on a four-bed system are presented. Under favorable conditions, this system produces better than 90% oxygen at a recovery of 17%. For the low-pressure ratio, such a recovery could not have been achieved without the pressure equalization step and the reduced purge operation. Recovery and throughput, however, are not as high as one would expect from a linear local equilibrium model. The self-broadening effect of the purge wave has been identified as the major cause of underperformance.