ON THE SPATIAL AND TEMPORAL BEHAVIOR IN LINEAR THERMOELASTICITY OF MATERIALS WITH VOIDS

The present article studies the spatial and temporal behavior of the solutions to the initial boundary value problems associated with the linear theory of thermoelastic materials with voids. The spatial behavior is described by spatial estimates of Saint-Venant type (for bounded bodies) and Phragmén-Lindelöf type (for unbounded bodies) with time-dependent and time-independent rates. Some appropriate time-weighted integral measures are used. The temporal behavior is studied using the Cesaro means of various parts of the total energy. The relations describing the asymptotic behavior of the Cesaro means are established.     

Knowledge acquisition by incremental learning from problem-solution pairs

This paper describes LEW (learning by watching), an implementation of a novel learning technique, and discusses its application to the learning of plans. LEW is a domain-independent learning system with user-limited autonomy that is designed to provide robust performance in realistic knowledge acquisition tasks in a variety of domains. It partly automates the knowledge acquisition process for different knowledge types, such as concepts, rules, and plans. The inputs to the system, which we call cues , consist of an environmental component and of pairs containing a problem and its solution. Unlike traditional forms of "learning from examples", in which the system uses the teacher's answer to improve the result of a prior generalization of an example, LEW treats the problem-solution or question-answer instances, i. e., the cues themselves, as the basic units for generalization.     

Recycling polystyrene into fuels by means of FCC: performance of various acidic catalysts

In accordance with the option of recycling plastics into fuels by dissolving them in standard feedstocks for the process of catalytic cracking of hydrocarbons, FCC, various acidic catalysts (zeolites ZSM-5, mordenite, Y, and a sulfur-promoted zirconia) were tested in the conversion of polystyrene dissolved into inert benzene at 550°C in a fluidized-bed batch reactor. Experiments were performed with very short contact times of up to 12 s. Main products were in the gasoline range, including benzene, toluene, ethylbenzene, styrene, and minor amounts of C_9–12 aromatics and light C₅₋ compounds. Coke was always produced in very significant amounts. All the products can be justified with basis on the properties of each catalyst and the various possible catalytic reaction pathways: cracking after protolytic attack on the polymer fragments, styrene oligomerization and subsequent cracking, or hydrogen transfer to styrene. Styrene would be mainly produced in this system from thermal cracking of the polymer as the initial step. If present, shape selectivity effects due to catalyst structure can influence significantly the prevalence of the various reactions, because they would interfere with those undergoing bulky transition states, like styrene oligomerization or hydrogen transfer. Even though sulfur-promoted zirconia is highly acidic, the low proportion of Brønsted-type acid sites does not allow the occurrence of secondary styrene reactions. It was shown that most favorable product distributions (higher yields of desirable products) are obtained on equilibrium commercial FCC catalysts.     

Transforming an Organization Through Prototyping: A Case Study

An organizational prototype is a forum to address simultaneously process, behavioral, and cultural change pursuant to business process redesign (BPR). in this case study, IS personnel facilitated organizational prototypes, thereby extending their knowledge of business systems to a new sphere, facilitating business process redesign. Success of the prototypes led to success in obtaining corporate funding for new client/server systems to support the changes in business operations.     

Moisture sorption isotherms and thermodynamic properties of apple Fuji and garlic

The moisture equilibrium isotherms of garlic and apple were determined at 50, 60 and 70 °C using the gravimetric static method. The experimental data were analysed using GAB, BET, Henderson–Thompson and Oswin equations. The isosteric heat and the differential entropy of desorption were determined by applying Clausius–Clapeyron and Gibbs–Helmholtz equations, respectively. The GAB equation showed the best fitting to the experimental data (R² > 99% and E% < 10%). The monolayer moisture content values for apple were higher than those for garlic at the studied temperatures; the values varied from 0.050 to 0.056 and from 0.107 to 0.168 for garlic and apple, respectively. The isosteric heat and the differential entropy of desorption were estimated in function of the moisture content. The values of these thermodynamic properties were higher for apple (in range 48–100 kJ mol^?1 and 14–150 J mol^?1 K^?1) than for garlic (in range 43–68 kJ mol^?1 and 0–66 J mol^?1 K^?1). The water surface area values decreased with increasing temperature. The Kelvin and the Halsey equations were used to calculate the pore size distribution.     

Determination of trenbolone and testosterone residues in meat by high pressure liquid chromatography (author's transl)

A new method for the qualitative and quantitative determination of trenbolone and testosterone residues in meat, liver, and kidney is described. The analytical procedure consists of the following steps: homogenisation of the meat sample with tetrahydrofurane; liquid-liquid partition first between acetonitrile and hexane, then between sodium hydroxide and petroleum ether/benzene; purification of a silica gel column. The purified sample is analysed by high pressure liquid chromatography using silica gel packings. Detection and quantitative determination are performed with a fluorescence and/or a spectrophotometric detector. Fluorescence measurements are carried out applying a self-made silica gel packed flow-cell. The detection limit in meat extracts is 50 ppb for testosterone and 5 ppb for trenbolone.     

A Graphical Method for Fire Design of Reinforced Concrete Beams

Fire Technology - Reinforced concrete beams lose resistance at high temperatures and so as to guarantee their good performance, it is mandatory to consider this accidental action in design. As an...     

New,Non‐quinone Fluorogeldanamycin Derivatives Strongly Inhibit Hsp90

Streptomyces hygroscopicus is a natural producer of geldanamycin. Mutasynthetic supplementation of an AHBA‐blocked mutant with all possible monofluoro 3‐aminobenzoic acids provided new fluorogeldanamycins. These showed strong antiproliferative activity and inhibitory effects on human heat shock protein Hsp90. Binding to Hsp90 in the low nanomolar range was determined from molecular modelling, AFM analysis and by calorimetric studies.