Fuzzy Models in Geotechnical Engineering and Construction Management

This article is devoted to a variety of applications of fuzzy models in civil engineering, presenting the current work of a group of researchers at the University of Innsbruck. With fuzzy methods and possibility theory as an encompassing framework, the following areas are addressed: uncertainties in geotechnical engineering, fuzzy finite‐element computation of a foundation raft, fuzzy dynamic systems, and processing uncertainty in project scheduling and cost planning.     

On the structure of polybutadiene: 4. 13C n.m.r. spectrum of polybutadienes with cis-1,4-, trans-1,4- and 1,2-units

¹³C n.m.r. spectra of polybutadienes with different contents of cis-1,4- and 1,2-units are assigned in the resonance region of the cis and trans carbon double bond. The observed signals are assigned to configurational triads.     

Kinetics of water adsorption in microporous aluminophosphate layers for regenerative heat exchangers

The performance of thick aluminophosphate molecular sieve layers for heat exchanger applications is evaluated. The aluminophosphate AlPO-18 (AEI structure type code) molecular sieve sorbent is coated on aluminium supports prior the sorption measurements. Two AlPO-18 samples with different morphological appearance, i.e. nano-sized crystals with monomodal size distribution and micron-sized crystals of varying sizes, are used to prepare layers with thickness in the range of 80–750 μm. As a binder component, polyvinyl alcohol (PVOH) was utilized in order to prepare mechanically stable layers, which are mechanically stable over numerous measuring cycles. The sorption measurements are conducted under canonical conditions at 40 °C. The AlPO-18 layers showed decreased mass flows with increasing the thickness. Additionally, the layers comprising nanosized crystals showed higher equilibrium loadings and faster kinetics compared to films based on micron-sized crystals. Following the kinetic studies of pressure, temperature and heat flow, it can be concluded that the heat transport is the rate limiting mechanism for thick aluminophosphate layers. Importantly, the diffusion limitation plays a role only for relatively thin microporous aluminophosphate layers (<200 μm). Below this thickness complete heat transfer is achieved within 2 min which allows fast heat exchanger cycles. Thus, the application of microporous aluminophosphate layers for heat transformation and storage applications is considered possible.     

Modeling search processes in space

The paper extends the well-known economic search model to take into account the fact that all search takes place in two-dimensional space. This adds arouting problem to thestopping problem usually discussed in the search literature. The paper shows that these two problems are interdependent and can only be solved simultaneously. This relates thespatial search problem as it is discussed in this paper toNP-Complete problems like the traveling salesman problem, some of the most complex problems in mathematics. The paper discusses this relationship and closes with some suggestions about how to circumvent this complexity.An earlier version of this paper was presented at the 30th European Congress, Istanbul, August 1990.     

CSs and USs: What's the difference?

Differences in processing representations of conditioned and unconditioned stimuli (CSs and UCSs) may result from either their temporal order in training (i.e., CSs precede UCSs) or the greater biological significance of UCSs. The CS- and UCS-preexposure effects were used to probe this question. These effects are similar except that context extinction between preexposure and training more readily attenuates the UCS- than the CS-preexposure effect. In Experiments 1, 2, and 5, context extinction following preexposure to the stimulus that later served as Event 1 in Event 1?→?Event 2 pairings alleviated the response deficit due to Event 1 preexposure if Event 1 was biologically significant. In Experiments 3 and 4, context extinction alleviated the response deficit due to Event 2 preexposure if Event 2 was biologically significant. Thus, biological significance and not temporal order determines how a representation will be processed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Overshadowing and latent inhibition counteract each other: support for the comparator hypothesis

In 4 conditioned lick suppression experiments with rats, the combined effects of latent inhibition treatment followed by overshadowing treatment were assessed as a test of the comparator hypothesis's (R.R. Miller & L.D. Matzel, 1988) explanations of overshadowing and latent inhibition. Experiments 1 and 2 confirmed the prediction of the comparator hypothesis that combined latent inhibition and overshadowing treatments attenuate the response deficit produced by either treatment alone. Furthermore, consistent with the comparator hypothesis, posttraining changes in the associative status of the putative comparator stimulus altered responding to the target conditioned stimulus (Experiment 3), and switching contexts between latent inhibition and overshadowing treatments (Experiment 4) eliminated the interaction between the latent inhibition and overshadowing treatments.     

Deactivation kinetics and modelling of coke removal under supercritical conditions for the example of ethylbenzene disproportionation

Deactivation kinetics and coke removal kinetics were derived from experimental studies on the disproportionation of ethylbenzene with a protonated Y-faujasite (Z-14) in a loop reactor under supercritical conditions. Derivation of the steady state kinetics of ethylbenzene disproportionation permitted determination of the catalyst activity. At small educt mole fractions of ethylbenzene, owing to the modest removal of coke the deactivation kinetics can be described by a power relationship. The rate of coke removal can be correlated with the activity and the deactivation rate of the catalyst.     

Synthesis of α, ω-dichloro polyindene and poly(isobutylene-b-indene-b-isobutylene) employing Kennedy's inifer technique

Summary Kennedy's inifer technique has been modified and used for the preparation of ,-dichloro polyindene (PInCl₂). This telechelic has subsequently been used as initiator for the cationic isobutylene polymerization in conjunction with AlEt₂-Cl coinitiator. The resulting materials have been characterized by fractionation and GPC investigations.